WESTLAKE CORP - Annual Report: 2011 (Form 10-K)

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K

For the Fiscal Year Ended December 31, 2011

or

For the Transition Period from              to             

Commission File No. 001-32260

Westlake Chemical Corporation

(Exact name of registrant as specified in its charter)

2801 Post Oak Boulevard, Suite 600

Houston, Texas 77056

(Address of principal executive offices, including zip code)

(713) 960-9111

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.    Yes  ¨    No  x

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Exchange Act.    Yes  ¨    No  x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  x

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act:

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act).    Yes  ¨    No  x

The aggregate market value of the registrant’s voting stock held by non-affiliates of the registrant on June 30, 2011, the end of the registrant’s most recently completed second fiscal quarter, based on a closing price on June 30, 2011 of $51.90 on the New York Stock Exchange was approximately $1.0 billion.

There were 66,535,075 shares of the registrant’s common stock outstanding as of February 17, 2012.

DOCUMENTS INCORPORATED BY REFERENCE:

Certain information required by Part II and Part III of this Form 10-K is incorporated by reference from the registrant’s definitive Proxy Statement to be filed pursuant to Regulation 14A with respect to the registrant’s 2012 Annual Meeting of Stockholders to be held on May 24, 2012.

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INDUSTRY AND MARKET DATA

Industry and market data used throughout this Form 10-K were obtained through internal company research, surveys and studies conducted by unrelated third parties and industry and general publications, including information from IHS Chemical and Chemical Data, Inc. We have not independently verified market and industry data from external sources. While we believe internal company estimates are reliable and market definitions are appropriate, neither such estimates nor these definitions have been verified by any independent sources.

PRODUCTION CAPACITY

Unless we state otherwise, annual production capacity estimates used throughout this Form 10-K represent rated capacity of the facilities at December 31, 2011. We calculated rated capacity by estimating the number of days in a typical year that a production unit of a plant is expected to operate, after allowing for downtime for regular maintenance, and multiplying that number by an amount equal to the unit’s optimal daily output based on the design feedstock mix. Because the rated capacity of a production unit is an estimated amount, actual production volumes may be more or less than the rated capacity.

NON-GAAP FINANCIAL MEASURES

The body of accounting principles generally accepted in the United States is commonly referred to as “GAAP.” For this purpose, a non-GAAP financial measure is generally defined by the Securities and Exchange Commission (“SEC”) as one that purports to measure historical or future financial performance, financial position or cash flows, but excludes or includes amounts that would not be so adjusted in the most comparable GAAP measures. In this report, we disclose so-called non-GAAP financial measures, primarily EBITDA. EBITDA is calculated as net income before interest expense, income taxes, depreciation and amortization. The non-GAAP financial measures described in this Form 10-K are not substitutes for the GAAP measures of earnings and cash flow.

EBITDA is included in this Form 10-K because our management considers it an important supplemental measure of our performance and believes that it is frequently used by securities analysts, investors and other interested parties in the evaluation of companies in our industry, some of which present EBITDA when reporting their results. We regularly evaluate our performance as compared to other companies in our industry that have different financing and capital structures and/or tax rates by using EBITDA. In addition, we utilize EBITDA in evaluating acquisition targets. Management also believes that EBITDA is a useful tool for measuring our ability to meet our future debt service, capital expenditures and working capital requirements, and EBITDA is commonly used by us and our investors to measure our ability to service indebtedness. EBITDA is not a substitute for the GAAP measures of earnings or of cash flow and is not necessarily a measure of our ability to fund our cash needs. In addition, it should be noted that companies calculate EBITDA differently and, therefore, EBITDA as presented for us may not be comparable to EBITDA reported by other companies. EBITDA has material limitations as a performance measure because it excludes interest expense, depreciation and amortization, and income taxes.

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PART I

General

We are a vertically integrated manufacturer and marketer of basic chemicals, vinyls, polymers and fabricated building products. Our products include some of the most widely used chemicals in the world, which are fundamental to many diverse consumer and industrial markets, including flexible and rigid packaging, automotive products, coatings, residential and commercial construction as well as other durable and non-durable goods. We operate in two principal business segments, Olefins and Vinyls, and we are an integrated producer of vinyls with substantial downstream integration into polyvinyl chloride, or PVC, building products.

We began operations in 1986 after our first polyethylene plant, an Olefins segment business, near Lake Charles, Louisiana was acquired from Occidental Petroleum Corporation. We began our vinyls operations in 1990 with the acquisition of a vinyl chloride monomer, or VCM, plant in Calvert City, Kentucky from the Goodrich Corporation. In 1992, we commenced our Vinyls segment building products operations after acquiring three PVC pipe plants. Since 1986, we have grown rapidly into an integrated producer of petrochemicals, polymers and building products. We achieved this by acquiring existing plants or constructing new plants (including our joint venture in China) and completing numerous capacity or production line expansions.

We benefit from highly integrated production facilities that allow us to process raw materials into higher value-added chemicals and building products. As of February 17, 2012, we had 11.8 billion pounds per year of aggregate production capacity at 13 manufacturing sites in North America. We also have a 59% interest in a joint venture in China that operates a vinyls facility.

Olefins Business

Products

Olefins are the basic building blocks used to create a wide variety of petrochemical products. We manufacture ethylene, polyethylene, styrene, and associated co-products at our manufacturing facility in Lake Charles and polyethylene at our Longview, Texas facility. We have two ethylene plants, two polyethylene plants and one styrene monomer plant at our Lake Charles complex. We have three polyethylene plants and a specialty polyethylene wax plant at our Longview facility. The following table illustrates our production capacities at February 17, 2012 by principal product and the primary end uses of these materials:

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Ethylene. Ethylene is the world’s most widely used petrochemical in terms of volume. It is the key building block used to produce a large number of higher value-added chemicals including polyethylene, EDC, VCM and styrene. We have the capacity to produce 2.5 billion pounds of ethylene per year at our Lake Charles complex and the capability to consume all of our production internally to produce polyethylene and styrene monomer in our Olefins business and to produce VCM and EDC in our Vinyls business. We also produce ethylene in our Vinyls segment at our Calvert City facility, all of which is used internally in the production of VCM. In addition, we produce ethylene co-products including chemical grade propylene, crude butadiene, pyrolysis gasoline and hydrogen. We sell our entire output of these co-products to external customers. In April 2011, we announced an expansion program to increase the ethane-based ethylene capacity of both of the ethylene units at our Lake Charles complex. We currently expect to complete the expansion of one of the two ethylene units by late 2012. The first cracker expansion is expected to increase ethylene capacity by approximately 230 – 240 million pounds annually, while also increasing feedstock flexibility. The additional capacity from this expansion is expected to provide ethylene for existing internal uses and may also be sold in the merchant market. In addition, we are currently evaluating expansion plans to increase the ethane-based ethylene capacity of the second ethylene unit at our Lake Charles complex.

Polyethylene. Polyethylene, the world’s most widely consumed polymer, is used in the manufacture of a wide variety of film, coatings and molded product applications primarily used in packaging. Polyethylene is generally classified as either LDPE, LLDPE or HDPE. The density correlates to the relative stiffness of the products. The difference between LDPE and LLDPE is molecular, and products produced from LLDPE are stronger than products produced from LDPE. LDPE is used in end products such as bread bags, dry cleaning bags, food wraps and milk carton and snack package coatings. LLDPE is used for higher film strength applications such as stretch film and heavy duty sacks. HDPE is used to manufacture products such as grocery, merchandise and trash bags, plastic containers, plastic closures and pipe.

We are the largest producer of LDPE in North America based on capacity and, in 2011, our annual capacity of 1.5 billion pounds was available in numerous formulations to meet the needs of our diverse customer base. We also have the capacity to produce 980 million pounds of LLDPE per year in various different formulations. Our Lake Charles facility has the capability to produce High-Density Polyethylene, or HDPE. We produce LDPE and LLDPE at Lake Charles and Longview. We sell polyethylene to external customers as a final product in pellet form.

Styrene. Styrene is used to produce derivatives such as polystyrene, acrylonitrile butadiene styrene, unsaturated polyester and synthetic rubber. These derivatives are used in a number of applications including consumer disposables, food packaging, housewares, paints and coatings, building materials, tires and toys. We produce styrene at our Lake Charles plant, where we have the capacity to produce 570 million pounds of styrene per year, all of which is sold to external customers.

Feedstocks

We are highly integrated along our olefins product chain. We produce most of the ethylene required to produce our polyethylene, VCM and styrene. Ethylene can be produced from either petroleum liquid feedstocks, such as naphtha, condensates and gas oils, or from natural gas liquid feedstocks, such as ethane, propane and butane. One of our ethylene plants uses ethane as its feedstock and the other can use ethane, ethane/propane mix, propane, butane and naphtha. We receive feedstock at our Lake Charles facility through several pipelines from a variety of suppliers in Texas and Louisiana. We also own a 200-mile ethylene pipeline that runs from Mont Belvieu, Texas to our Longview facility. In addition, we own a 50% interest in a 104-mile natural gas liquids pipeline from Mont Belvieu to our Lake Charles complex.

In addition to our internally supplied ethylene, we also acquire ethylene from third parties in order to supply a portion of our ethylene requirements. We acquire butene and hexene to manufacture polyethylene and benzene to manufacture styrene. We receive butene and hexene at the Lake Charles complex and hexene at the Longview

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complex via rail car from several suppliers. We receive benzene via barges, ships and pipeline pursuant to short-term arrangements. We purchase butene and hexene pursuant to multi-year contracts, some of which are renewable for an additional term subject to either party to the contract notifying the other party that it does not wish to renew the contract.

Marketing, Sales and Distribution

We use the majority of our Lake Charles ethylene production in our polyethylene, styrene and VCM operations. We sell the remainder to external customers. In addition, we sell our ethylene co-products to external customers. Our primary ethylene co-products are chemical grade propylene, crude butadiene, pyrolysis gasoline and hydrogen. The majority of sales in our Olefins business are made under long-term agreements.

We typically ship our ethylene and propylene via a pipeline system that connects our plants to numerous customers. Our hydrogen is sold via pipeline to a single customer. We also have storage agreements and exchange agreements that allow us access to customers who are not directly connected to the pipeline system. We transport our polyethylene, styrene, crude butadiene and pyrolysis gasoline by rail or truck. Additionally, styrene can be transported by barge or ship.

We have an internal sales force that sells directly to our customers. Our polyethylene customers are some of the nation’s largest producers of film and flexible packaging. In 2011, no single customer accounted for 10% or more of net sales for the Olefins segment.

Competition

The markets in which our Olefins business operates are highly competitive. We compete on the basis of price, customer service, product deliverability, quality, consistency and performance. Our competitors in the ethylene, polyethylene and styrene markets are typically some of the world’s largest chemical companies, including Chevron Phillips Chemical Company LP, The Dow Chemical Company, ExxonMobil Chemical Company, INEOS (successor to BP Chemicals Ltd.), LyondellBasell Industries and NOVA Chemicals Corporation, a subsidiary of The International Petroleum Investment Company of the Emirate of Abu Dhabi.

Vinyls Business

Products

Principal products in our integrated Vinyls segment include PVC, VCM, EDC, chlorine, caustic soda and ethylene. We also manufacture and sell building products fabricated from PVC, including pipe, fence and deck, and window and door components. We manage our integrated Vinyls production chain, from the basic chemicals to finished building products, to maximize product margins and capacity utilization. Our primary manufacturing facilities are located in our Calvert City and Geismar, Louisiana complexes. Our Calvert City facility includes an ethylene plant, a chlor-alkali plant, a VCM plant, a PVC plant and a large diameter PVC pipe plant. Our Geismar facility includes an EDC plant, a VCM plant and a PVC plant. As of February 17, 2012, we operated and owned 10 building product facilities and owned a 59% interest in a joint venture in China that produces PVC resin, building products and PVC film and sheet.

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The following table illustrates our production capacities at February 17, 2012 by principal product and the end uses of these products:

PVC. PVC, the world’s third most widely used plastic, is an attractive alternative to traditional materials such as glass, metal, wood, concrete and other plastic materials because of its versatility, durability and cost-competitiveness. PVC is produced from VCM, which is, in turn, made from chlorine and ethylene. PVC compounds are made by combining PVC resin with various additives in order to make either rigid and impact-resistant or soft and flexible compounds. The various compounds are then fabricated into end-products through extrusion, calendering, injection-molding or blow-molding. Flexible PVC compounds are used for wire and cable insulation, automotive interior and exterior trims and packaging. Rigid extrusion PVC compounds are commonly used in window frames, vertical blinds and construction products, including pipe and siding. Injection-molding PVC compounds are used in specialty products such as computer housings and keyboards, appliance parts and bottles. We have the capacity to produce 1.1 billion pounds of PVC per year at our Calvert City facility and 600 million pounds per year at our Geismar facility. We have the capacity to use a majority of our PVC internally in the production of our building products. The remainder of our PVC is sold to downstream fabricators and the export market.

VCM. VCM is used to produce PVC, solvents and PVC-related products. We use ethylene and chlorine to produce VCM. We have the capacity to produce 1.3 billion pounds of VCM per year at our Calvert City facility and 550 million pounds per year at our Geismar facility. The majority of our VCM is used internally in our PVC operations.

Chlorine and Caustic Soda. We combine salt and electricity to produce chlorine and caustic soda, commonly referred to as chlor-alkali, at our Calvert City facility. We use our chlorine production in our VCM plants. We currently have the capacity to supply approximately 50% of our chlorine requirements internally. We purchase the remaining amount at market prices. Our caustic soda is sold to external customers who use it for, among other things, the production of pulp and paper, organic and inorganic chemicals and alumina. In August 2010, we announced that we intend to proceed with the previously announced construction of a new chlor-alkali plant to be located at our vinyls manufacturing complex in Geismar. The new chlor-alkali unit is designed to produce up to 350,000 ECUs annually upon completion, bringing our total ECU capacity to

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625,000 per year. The new plant will improve the vertical integration of our vinyls business from chlorine downstream into VCM and PVC and increase caustic soda sales. The project is currently targeted for start-up in the second half of 2013.

Ethylene. We use all of the ethylene produced at Calvert City internally to produce VCM, and Calvert City has the capacity to produce approximately 50% of the ethylene required for our total VCM production. We obtain the remainder of the ethylene we need for our Vinyls business from our Olefins business. In December 2011, we announced plans to perform a major modification of the ethylene production facility at our Calvert City complex. The modification is expected to reduce costs and improve operating efficiency and energy consumption. We currently expect the modification to be completed by mid-2013. In addition, we are currently evaluating conversion from propane to ethane feedstock for our ethylene production facility at Calvert City in order to capitalize on available low cost ethane and other “light” feedstock being developed in North America.

Building Products. Products made from PVC are used in construction materials ranging from water and sewer systems to home and commercial applications for fence, deck, window and door systems. We manufacture and market water, sewer, irrigation and conduit pipe products under the “North American Pipe” brand. We also manufacture and market PVC fence, decking, windows and door profiles under the “Westech Building Products” brand. All of our building products are sold to external customers. All of the PVC we require for our building products is produced internally. In June 2011, we closed our Springfield, Kentucky PVC pipe facility, with an annual capacity of 90 million pounds. The combined capacity of our 10 building products plants is 1.1 billion pounds per year.

China Joint Venture. We own a 59% interest in Suzhou Huasu Plastics Co. Ltd., a joint venture based near Shanghai, China. Our joint venture partners are a local Chinese chemical company and a subsidiary of INEOS. In 1995, this joint venture constructed and began operating a PVC film plant that has a current annual capacity of 145 million pounds of PVC film. In 1999, the joint venture constructed and began operating a PVC resin plant that has an annual capacity of 300 million pounds of PVC resin. In 2008, the joint venture began producing building products with an annual capacity of 33 million pounds of product.

Feedstocks

We are highly integrated along our vinyls production chain. We produce most of the ethylene, all of the VCM and PVC and approximately 50% of our chlorine requirements used in our Vinyls business. The remainder of our chlorine requirements is purchased at market prices. Ethylene produced at our Calvert City facility utilizes propane feedstock. We purchase the salt required for our chlor-alkali plant pursuant to a long-term contract. We purchase electricity for our Calvert City facility production from the Tennessee Valley Authority under a long-term contract.

We are an integrated producer of vinyls with substantial downstream integration into building products. Our Calvert City and Geismar facilities supply all the PVC required for our building products plants. The remaining feedstocks for building products include pigments, fillers and stabilizers, which we purchase under short-term contracts based on prevailing market prices.

Marketing, Sales and Distribution

We are the second largest manufacturer of PVC pipe by volume in the United States. We sell a majority of our PVC pipe through a combination of manufacturer’s representatives and our internal sales force to distributors who serve the wholesale PVC pipe market. We use a regional sales approach that allows us to provide focused customer service and to meet the specified needs of individual customers. We use an internal sales force to market and sell our fence, window and door profiles. We have the capacity to use a majority of our PVC internally in the production of our building products. The remainder of our PVC is sold to downstream fabricators and the export market.

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We sell substantially all of our caustic soda production to external customers, concentrating on customers in Calvert City’s geographical area to minimize transportation costs. In 2011, no single customer accounted for 10% or more of net sales for the Vinyls segment.

Competition

Competition in the vinyls market is based on price, product availability, product performance and customer service. We compete in the vinyls market with other producers including Formosa Plastics Corporation, Georgia Gulf Corporation, Oxy Chem, LP and Shintech, Inc.

Competition in the building products market is based on price, on-time delivery, product quality, customer service and product consistency. We compete in the building products market with other producers and fabricators including Diamond Plastics Corporation and JM Eagle. We are the second largest manufacturer of PVC pipe by volume in the United States. We are also one of the largest manufacturers of PVC fence components by volume in the United States.

Environmental and Other Regulation

As is common in our industry, obtaining, producing and distributing many of our products involves the use, storage, transportation and disposal of large quantities of toxic and hazardous materials, and our manufacturing operations require the generation and disposal of large quantities of hazardous wastes. We are subject to extensive, evolving and increasingly stringent federal, state and local environmental laws and regulations, which address, among other things, the following:

We are subject to environmental laws and regulations that can impose civil and criminal sanctions and that may require us to mitigate the effects of contamination caused by the release or disposal of hazardous substances into the environment. An owner or operator of property may be held strictly liable for remediating contamination without regard to whether that person caused the contamination, and without regard to whether the practices that resulted in the contamination were legal at the time they occurred. Because several of our production sites have a history of industrial use, it is impossible to predict precisely what effect these legal requirements will have on us.

Contract Disputes with Goodrich and PolyOne. In connection with the 1990 and 1997 acquisitions of the Goodrich Corporation (“Goodrich”) chemical manufacturing complex in Calvert City, Goodrich agreed to indemnify us for any liabilities related to preexisting contamination at the complex. For our part, we agreed to indemnify Goodrich for post-closing contamination caused by our operations. The soil and groundwater at the complex, which does not include our nearby PVC facility, had been extensively contaminated under Goodrich’s operations. In 1993, Goodrich spun off the predecessor of PolyOne Corporation (“PolyOne”), and that predecessor assumed Goodrich’s indemnification obligations relating to preexisting contamination.

In 2003, litigation arose among us, Goodrich and PolyOne with respect to the allocation of the cost of remediating contamination at the site. The parties settled this litigation in December 2007, and the case was dismissed. In the settlement the parties agreed that, among other things: (1) PolyOne would pay 100% of the costs (with specified exceptions), net of recoveries or credits from third parties, incurred with respect to environmental issues at the Calvert City site from August 1, 2007 forward; (2) either we or PolyOne might, from

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time to time in the future (but not more than once every five years), institute an arbitration proceeding to adjust that percentage; and (3) we and PolyOne would negotiate a new environmental remediation utilities and services agreement to cover our provision to or on behalf of PolyOne of certain environmental remediation services at the site. The current environmental remediation activities at the Calvert City complex do not have a specified termination date but are expected to last for the foreseeable future. The costs incurred by PolyOne to provide the environmental remediation services were $3.3 million and $3.0 million in 2011 and 2010, respectively. On March 17, 2010, we received notice of PolyOne’s intention to commence an arbitration proceeding under the settlement agreement. In this proceeding, PolyOne seeks to readjust the percentage allocation of costs and to recover approximately $1.4 million from us in reimbursement of previously paid remediation costs. The arbitration is currently stayed.

Administrative Proceedings. There are several administrative proceedings in Kentucky involving us, Goodrich and PolyOne related to the same manufacturing complex in Calvert City. In 2003, the Kentucky Environmental and Public Protection Cabinet (the “Cabinet”) re-issued Goodrich’s Resource Conservation and Recovery Act (“RCRA”) permit which requires Goodrich to remediate contamination at the Calvert City manufacturing complex. Both Goodrich and PolyOne challenged various terms of the permit in an attempt to shift Goodrich’s clean-up obligations under the permit to us. We intervened in the proceedings. The Cabinet has suspended all corrective action under the RCRA permit in deference to a remedial investigation and feasibility study (“RIFS”) being conducted pursuant to an Administrative Settlement Agreement (“AOC”), which became effective on December 9, 2009. See “Change in Regulatory Regime” below. The proceedings have been postponed. Periodic status conferences will be held to evaluate whether additional proceedings will be required. On September 19, 2011, we filed a motion to dismiss the remaining proceedings, which was denied on December 29, 2011.

Change in Regulatory Regime. In May 2009, the Cabinet sent a letter to the U.S. Environmental Protection Agency (“EPA”) requesting the EPA’s assistance in addressing contamination at the Calvert City site under the U.S. Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”). In its response to the Cabinet also in May 2009, the EPA stated that it concurred with the Cabinet’s request and would incorporate work previously conducted under the Cabinet’s RCRA authority into the EPA’s cleanup efforts under CERCLA. Since 1983, the EPA has been addressing contamination at an abandoned landfill adjacent to our plant which had been operated by Goodrich and which was being remediated pursuant to CERCLA. During the past two years, the EPA has directed Goodrich and PolyOne to conduct additional investigation activities at the landfill and at our plant. In June 2009, the EPA notified us that we may have potential liability under section 107(a) of CERCLA at our plant site. Liability under section 107(a) of CERCLA is strict and joint and several. The EPA also identified Goodrich and PolyOne, among others, as potentially responsible parties at the plant site. We negotiated, in conjunction with the other potentially responsible parties, the AOC and an order to conduct the RIFS. The parties submitted and received EPA approval for a RIFS work plan to implement the AOC. The parties are currently conducting the RIFS.

Monetary Relief. Except as noted above, with respect to the settlement of the contract litigation among us, Goodrich and PolyOne, none of the court, the Cabinet nor the EPA has established any allocation of the costs of remediation among the various parties that are involved in the judicial and administrative proceedings discussed above. At this time, we are not able to estimate the loss or reasonable possible loss, if any, on our financial statements that could result from the resolution of these proceedings. Any cash expenditures that we might incur in the future with respect to the remediation of contamination at the complex would likely be spread out over an extended period. As a result, we believe it is unlikely that any remediation costs allocable to us will be material in terms of expenditures made in any individual reporting period.

EPA Audit of Ethylene Units in Lake Charles. During 2007, the EPA conducted an audit of our ethylene units in Lake Charles, with a focus on leak detection and repair, or LDAR. In January 2008, the U.S. Department of Justice, or DOJ, notified us that the EPA had referred the matter to the DOJ to bring a civil case against us alleging violations of various environmental laws and regulations. The DOJ informed us that it would seek monetary penalties and require us to implement an “enhanced LDAR” program for the ethylene units. The EPA has proposed a settlement and provided a draft consent decree, which would require our Lake Charles facilities to

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undertake an enhanced LDAR program and would require payment of a civil penalty. We are engaged in negotiations with the EPA. We have recorded an accrual for a probable loss related to monetary penalties. Although the ultimate amount of liability is not ascertainable, we believe that the resolution of this matter will not have a material adverse effect on our financial condition, results of operations or cash flows.

General. It is our policy to comply with all environmental, health and safety requirements and to provide safe and environmentally sound workplaces for our employees. In some cases, compliance can be achieved only by incurring capital expenditures, and we are faced with instances of noncompliance from time to time. In 2011, we made capital expenditures of $6.1 million related to environmental compliance. We estimate that we will make capital expenditures of $6.0 million in 2012 and $7.0 million in 2013, respectively, related to environmental compliance. A significant percentage of the 2012 and 2013 estimated amounts are related to equipment replacement and upgrades. We anticipate that stringent environmental regulations will continue to be imposed on us and the industry in general. Although we cannot predict with certainty future expenditures, management believes that our current spending trends will continue.

It is difficult to estimate the future costs of environmental protection and remediation because of many uncertainties, including uncertainties about the status of laws, regulations and information related to individual locations and sites and our ability to rely on third parties to carry out such remediation. Subject to the foregoing, but taking into consideration our experience regarding environmental matters of a similar nature and facts currently known, and except for the outcome of pending litigation and regulatory proceedings, which we cannot predict, but which could have a material adverse effect on us, we believe that capital expenditures and remedial actions to comply with existing laws governing environmental protection will not have a material adverse effect on our business and financial results.

Employees

As of December 31, 2011, we had 1,811 employees in the following areas:

Approximately 12% of our employees are represented by labor unions and all of these employees are working under collective bargaining agreements. The collective bargaining agreements expire in 2014. There have been no strikes or lockouts, and we have not experienced any work stoppages throughout our history. We believe that our relationship with the local union officials and bargaining committees is open and positive.

Technology

Historically, our technology strategy has been to selectively acquire licenses for and to improve upon third-party proprietary technology. Our selection process incorporates many factors, including the cost of the technology, our customers’ requirements, raw material and energy consumption rates, product quality, capital costs, maintenance requirements and reliability. We own a patent portfolio of intellectual property developed by a focused research and process technology development group. We also evaluate and access third-party technology for our Olefins businesses. After acquiring a technology, we devote considerable effort to effectively employ the technology and further its development, with a view towards continuous improvement of our competitive position.

We license technology from a number of third-party providers as follows:

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With the exception of Aspen Technology, Badger EBMax and Chlorine Engineers, all of the other licenses are perpetual and have been paid in full.

We have also selectively granted licenses to our patented Energx^® technology for LLDPE production and for proprietary LDPE reactor mixing technology.

Segment and Geographic Information

Information regarding sales, income (loss) from operations and assets attributable to each of our industry segments, Olefins and Vinyls, and geographical information is presented in Note 19 to our consolidated financial statements included in Item 8 of this Form 10-K.

Available Information

Our Web site address is www.westlake.com. We make our Web site content available for information purposes only. It should not be relied upon for investment purposes, nor is it incorporated by reference in this Form 10-K. We make available on this Web site under “Investor Relations/SEC Filings,” free of charge, our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, amendments to those reports and proxy statements as soon as reasonably practicable after we electronically file those materials with, or furnish those materials to, the SEC. The SEC also maintains a Web site at www.sec.gov that contains reports, proxy statements and other information regarding SEC registrants, including us.

We intend to satisfy the requirement under Item 5.05 of Form 8-K to disclose any amendments to our Code of Ethics and any waiver from a provision of our Code of Ethics by posting such information on our Web site at www.westlake.com at “Investor Relations/Corporate Governance.”

Cyclicality in the petrochemical industry has in the past, and may in the future, result in reduced operating margins or operating losses.

Our historical operating results reflect the cyclical and volatile nature of the petrochemical industry. The industry is mature and capital intensive. Margins in this industry are sensitive to supply and demand balances both domestically and internationally, which historically have been cyclical. The cycles are generally characterized by periods of tight supply, leading to high operating rates and margins, followed by periods of oversupply primarily resulting from significant capacity additions, leading to reduced operating rates and lower margins.

Moreover, profitability in the petrochemical industry is affected by the worldwide level of demand along with vigorous price competition which may intensify due to, among other things, new domestic and foreign industry capacity. In general, weak economic conditions either in the United States or in the world tend to reduce demand and put pressure on margins. It is not possible to predict accurately the supply and demand balances, market conditions and other factors that will affect industry operating margins in the future.

Some olefins industry consultants predict that significant increases in worldwide ethylene and ethylene derivative capacity, which have occurred over the past four years, primarily in the Middle East and Asia, may continue for the next several years. As a result, our Olefins segment operating margins may be negatively impacted.

PVC industry operating rates have dropped from peak levels in the second half of 2006 to much lower levels in 2011. In addition, weakness in the U.S. construction markets, which began in the third quarter of 2006, and the

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subsequent budgetary constraints in municipal spending, have contributed to lower domestic demand for our vinyls products and negatively impacted our Vinyls segment. Looking forward, our Vinyls segment operating rates and margins may continue to be negatively impacted by the slow recovery of U.S. construction markets and North American PVC capacity additions.

We sell commodity products in highly competitive markets and face significant competition and price pressure.

We sell our products in highly competitive markets. Due to the commodity nature of many of our products, competition in these markets is based primarily on price and to a lesser extent on performance, product quality, product deliverability and customer service. As a result, we generally are not able to protect our market position for these products by product differentiation and may not be able to pass on cost increases to our customers. Accordingly, increases in raw material and other costs may not necessarily correlate with changes in prices for these products, either in the direction of the price change or in magnitude. Specifically, timing differences in pricing between raw material prices, which may change daily, and contract product prices, which in many cases are negotiated only monthly or less often, sometimes with an additional lag in effective dates for increases, have had and may continue to have a negative effect on profitability. Significant volatility in raw material costs tends to place pressure on product margins as sales price increases could lag behind raw material cost increases. Conversely, when raw material costs decrease, customers could seek relief in the form of lower sales prices.

Volatility in costs of raw materials and energy may result in increased operating expenses and adversely affect our results of operations and cash flow.

Significant variations in the costs and availability of raw materials and energy may negatively affect our results of operations. These costs have risen significantly in the past due primarily to oil and natural gas cost increases. We purchase significant amounts of ethane and propane feedstock, natural gas, ethylene, chlorine and salt to produce several basic chemicals. We also purchase significant amounts of electricity to supply the energy required in our production processes. The cost of these raw materials and energy, in the aggregate, represents a substantial portion of our operating expenses. The prices of raw materials and energy generally follow price trends of, and vary with market conditions for, crude oil and natural gas, which are highly volatile and cyclical. Our results of operations have been and could in the future be significantly affected by increases in these costs. Price increases increase our working capital needs and, accordingly, can adversely affect our liquidity and cash flow. In addition, because we utilize the first-in, first-out (“FIFO”) method of inventory accounting, during periods of falling raw material prices and declining sales prices, our results of operations for a particular reporting period could be negatively impacted as the lower sales prices would be reflected in operating income more quickly than the corresponding drop in feedstock costs. We use derivative instruments in an attempt to reduce price volatility risk on some feedstock commodities. In the future, we may decide not to hedge any of our raw material costs or any hedges we enter into may not have successful results. Also, our hedging activities involve credit risk associated with our hedging counterparties, and a deterioration in the financial markets could adversely affect our hedging counterparties and their abilities to fulfill their obligations to us.

In addition, higher natural gas prices could adversely affect the ability of many domestic chemical producers to compete internationally since U.S. producers are disproportionately reliant on natural gas and natural gas liquids as an energy source and as a raw material. In addition to the impact that this has on our exports, reduced competitiveness of U.S. producers also has in the past increased the availability of chemicals in North America, as U.S. production that would otherwise have been sold overseas was instead offered for sale domestically, resulting in excess supply and lower prices in North America. We could also face the threat of imported products from countries that have a cost advantage.

External factors beyond our control can cause fluctuations in demand for our products and in our prices and margins, which may negatively affect our results of operations and cash flow.

External factors beyond our control can cause volatility in raw material prices, demand for our products, product prices and volumes and deterioration in operating margins. These factors can also magnify the impact of economic cycles on our business and results of operations. Examples of external factors include:

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We believe that events in the Middle East have had a particular influence on demand, prices and margins in the past and may continue to do so in the future. In addition, a number of our products are highly dependent on durable goods markets, such as housing and construction, which are themselves particularly cyclical. The significant weakening of the U.S. residential housing market during recent years has had an adverse effect on demand and margins for our products. If the global economy worsens in general, or the U.S. residential housing market worsens in particular, demand for our products and our income and cash flow could be adversely affected to an even greater degree.

We may reduce production at or idle a facility for an extended period of time or exit a business because of high raw material prices, an oversupply of a particular product and/or a lack of demand for that particular product, which makes production uneconomical. Since 2007 we have closed a PVC window and door components plant and three PVC pipe plants. Temporary outages sometimes last for several quarters or, in certain cases, longer and cause us to incur costs, including the expenses of maintaining and restarting these facilities. Factors such as increases in raw material costs or lower demand in the future may cause us to further reduce operating rates, idle facilities or exit uncompetitive businesses.

Hostilities in the Middle East and/or the occurrence or threat of occurrence of terrorist attacks such as those against the United States on September 11, 2001 could adversely affect the economies of the United States and other developed countries. A lower level of economic activity could result in a decline in demand for our products, which could adversely affect our net sales and margins and limit our future growth prospects. In addition, these risks have increased in the past, and may continue to increase in the future. Volatility in prices for crude oil and natural gas could also result in increased feedstock costs. In addition, these risks could cause increased instability in the financial and insurance markets and could adversely affect our ability to access capital and to obtain insurance coverage that we consider adequate or is otherwise required by our contracts with third parties.

The global economic downturn has had and may continue to have a negative impact on our business and financial condition.

The global economic downturn has had, and may continue to have, an impact on our business and our financial condition. Our ability to access the capital markets may be severely restricted at a time when we would like, or need, to access such markets, which could have an impact on our flexibility to react to changing economic and business conditions. In addition, the availability of additional financing at cost effective interest rates cannot be assured. The economic downturn could have an impact on the lenders under our revolving credit facility or on our customers and suppliers, causing them to fail to meet their obligations to us. Additionally, the economic downturn resulted in reduced demand for our products, which had a negative impact on our revenues and profits. Further, reduced levels of accounts receivables and inventory may affect our credit facility borrowing base. Our credit facility allows us to borrow up to (1) 85% of the net amount of eligible accounts receivable, plus (2) the lesser of (a) 70% of the value of the lower of cost or market of eligible inventory, or (b) 85% of the appraised net orderly liquidation value of all eligible inventory, plus (3) 100% of cash held in an account with the agent under the credit facility and subject to a control agreement with the agent, minus (4) such reserves as the agent may establish.

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Our inability to compete successfully may reduce our operating profits.

The petrochemical industry is highly competitive. Historically, there have been a number of mergers, acquisitions, spin-offs and joint ventures in the industry. This restructuring activity has resulted in fewer but more competitive producers, many of which are larger than we are and have greater financial resources than we do. Among our competitors are some of the world’s largest chemical companies and chemical industry joint ventures. Competition within the petrochemical industry and in the manufacturing of building products is affected by a variety of factors, including:

Changes in the competitive environment could have a material adverse effect on our business and our operations. These changes could include:

Our production facilities process some volatile and hazardous materials that subject us to operating risks that could adversely affect our operating results.

We have four major manufacturing facilities: our olefins complex in Lake Charles, our polyethylene complex in Longview, our vinyls complex in Calvert City and our vinyls facility in Geismar. Our operations are subject to the usual hazards associated with commodity chemical and plastics manufacturing and the related use, storage, transportation and disposal of feedstocks, products and wastes, including:

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According to some experts, global climate change could result in heightened hurricane activity in the Gulf of Mexico. If this materializes, severe weather and natural disaster hazards could pose an even greater risk for our facilities, particularly those in Louisiana.

All these hazards can cause personal injury and loss of life, catastrophic damage to or destruction of property and equipment and environmental damage, and may result in a suspension of operations and the imposition of civil or criminal penalties. We could become subject to environmental claims brought by governmental entities or third parties. A loss or shutdown over an extended period of operations at any one of our four major operating facilities would have a material adverse effect on us. We maintain property, business interruption and casualty insurance that we believe is in accordance with customary industry practices, but we cannot be fully insured against all potential hazards incident to our business, including losses resulting from war risks or terrorist acts. As a result of market conditions, premiums and deductibles for certain insurance policies can increase substantially and, in some instances, certain insurance may become unavailable or available only for reduced amounts of coverage. If we were to incur a significant liability for which we were not fully insured, it could have a material adverse effect on our financial position.

Our operations and assets are subject to extensive environmental, health and safety laws and regulations.

We use large quantities of hazardous substances and generate large quantities of hazardous wastes in our manufacturing operations. Due to the large quantities of hazardous substances and wastes, our industry is highly regulated and monitored by various environmental regulatory authorities. As such, we are subject to extensive federal, state and local laws and regulations pertaining to pollution and protection of the environment, health and safety, which govern, among other things, emissions to the air, discharges onto land or waters, the maintenance of safe conditions in the workplace, the remediation of contaminated sites, and the generation, handling, storage, transportation, treatment and disposal of waste materials. Some of these laws and regulations are subject to varying and conflicting interpretations. Many of these laws and regulations provide for substantial fines and potential criminal sanctions for violations and require the installation of costly pollution control equipment or operational changes to limit pollution emissions and/or reduce the likelihood or impact of hazardous substance releases, whether permitted or not. For example, all four of our petrochemical facilities, in Lake Charles, Longview, Calvert City and Geismar, may require improvements to comply with certain changes in process safety management requirements.

On February 14, 2012, the Environmental Protection Agency (“EPA”) finalized maximum achievable control technology (“MACT”) standards for major sources and generally available control technology (“GACT”) standards for area sources of PVC production. The rule sets emission limits and work practice standards for total organic air toxics and for three specific air toxics: vinyl chloride, chlorinated di-benzo dioxins and furans (“CD/DF”), and hydrogen chloride and includes requirements to demonstrate initial and continuous compliance with the emission standards. We are currently evaluating the effect these new standards could have on our business. This rule or other new or proposed rules may result in an increase in regulations, which could increase our costs or reduce our production, which could have a material adverse effect on our business, financial condition, operating results or cash flow. In addition, we cannot accurately predict future developments, such as increasingly strict environmental and safety laws or regulations, and inspection and enforcement policies, as well as resulting higher compliance costs, which might affect the handling, manufacture, use, emission, disposal or remediation of products, other materials or hazardous and non-hazardous waste, and we cannot predict with certainty the extent of our future liabilities and costs under environmental, health and safety laws and regulations. These liabilities and costs may be material.

Legislation to regulate emissions of greenhouse gases (“GHGs”) has been introduced in the U.S. Congress, and there has been a wide-ranging policy debate, both in the U.S. and internationally, regarding the impact of these gases and possible means for their regulation. Some of the proposals would require industries to meet stringent new standards that would require substantial reductions in carbon emissions. Those reductions could be costly and difficult to implement. In addition, efforts have been made and continue to be made in the international community toward the adoption of international treaties or protocols that would address global

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climate change issues, such as the United Nations Climate Change Conference in Durban in 2011. In the U.S., the EPA has adopted rules requiring the reporting of GHG emissions from specified large GHG emission sources, on an annual basis, beginning in 2011 for emissions occurring after January 1, 2010, as well as from certain oil and natural gas production facilities, on an annual basis, beginning in 2012 for emissions occurring in 2011. Further, following a finding by the EPA that certain GHGs represent an endangerment to human health, the EPA finalized a rule to address permitting of GHG emissions from stationary sources under the Clean Air Act’s New Source Review Prevention of Significant Deterioration (“PSD”) and Title V programs. This final rule “tailors” the PSD and Title V programs to apply to certain stationary sources of GHG emissions in a multi-step process, with the largest sources first subject to permitting. Facilities required to obtain PSD permits for their GHG emissions also will be required to reduce those emissions according to “best available control technology” standards for GHGs that will be established by the states or, in some instances, by the EPA on a case-by-case basis.

Legislation or regulation by the EPA, and any international agreements to which the United States may become a party, that control or limit GHG emissions or otherwise seek to address climate change could adversely affect our energy supply and costs, the costs of raw materials derived from fossil fuels, our general costs of production and the demand for our products. The cost of complying with any new law, regulation or treaty will depend on the details of the particular program.

We also may face liability for alleged personal injury or property damage due to exposure to chemicals or other hazardous substances at our facilities or to chemicals that we otherwise manufacture, handle or own. Although these types of claims have not historically had a material impact on our operations, a significant increase in the success of these types of claims could have a material adverse effect on our business, financial condition, operating results or cash flow.

Environmental laws may have a significant effect on the nature and scope of, and responsibility for, cleanup of contamination at our current and former operating facilities, the costs of transportation and storage of raw materials and finished products, the costs of reducing emissions and the costs of the storage and disposal of wastewater. In addition, the federal CERCLA and similar state laws impose joint and several liability for the costs of remedial investigations and actions on the entities that generated waste, arranged for disposal of the wastes, transported to or selected the disposal sites and the past and present owners and operators of such sites. All such potentially responsible parties (or any one of them, including us) may be required to bear all of such costs regardless of fault, legality of the original disposal or ownership of the disposal site. In addition, CERCLA and similar state laws could impose liability for damages to natural resources caused by contamination.

Although we seek to take preventive action, our operations are inherently subject to accidental spills, discharges or other releases of hazardous substances that may make us liable to governmental entities or private parties. This may involve contamination associated with our current and former facilities, facilities to which we sent wastes or by-products for treatment or disposal and other contamination. Accidental discharges may occur in the future, future action may be taken in connection with past discharges, governmental agencies may assess damages or penalties against us in connection with any past or future contamination, or third parties may assert claims against us for damages allegedly arising out of any past or future contamination. In addition, we may be liable for existing contamination related to certain of our facilities for which, in some cases, we believe third parties are liable in the event such third parties fail to perform their obligations. For further discussion of such existing contamination, see Item 1, “Business—Environmental and Other Regulation.”

We may not be able to complete an acquisition of Georgia Gulf Corporation and, even if such a transaction is completed, we may not realize the benefits of such a transaction; we could have difficulties in integrating the operations of Georgia Gulf; and an acquisition of Georgia Gulf could have other adverse consequences for us, including the use of a significant amount of our cash and the incurrence of additional debt.

We submitted a proposal to Georgia Gulf Corporation (“Georgia Gulf”) to acquire all of its outstanding shares for $30.00 per share in cash, or a total of approximately $1.1 billion, with the expectation that completing

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such an acquisition would result in various benefits, including, among other things, synergies, cost savings and operating efficiencies. Georgia Gulf rejected our proposal on January 16, 2012 and adopted a stockholder rights plan. On February 1, 2012, we submitted a new proposal to Georgia Gulf, increasing our offer to $35.00 per share in cash, or a total of approximately $1.2 billion, with the possibility of offering our common stock as part of the offer consideration. On that date, Georgia Gulf also publicly rejected our increased offer. We may not be able to complete such an acquisition on the terms in our proposal, or at all, and the failure to complete the acquisition could have adverse consequences for us, including a decline in the market value of our common stock. Even if we do complete such an acquisition, we may not achieve the benefits we anticipated at the levels expected or at all. See “We may pursue acquisitions, dispositions and joint ventures and other transactions that may impact our results of operations and financial condition.”

In addition, we could have difficulties or experience delays in connection with the integration of the operations of Georgia Gulf, if acquired. See “We may have difficulties integrating the operations of acquired businesses.” Any unexpected difficulties or delays incurred in connection with the integration of such an acquisition could have an adverse effect on our business, results of operations or financial condition.

Further, an acquisition of Georgia Gulf could require the use of a significant amount of our cash and the incurrence of additional debt, which could have adverse consequences for us. See “Our level of debt could adversely affect our ability to operate our business” and “To service our indebtedness, we will require a significant amount of cash. Our ability to generate cash depends on many factors beyond our control.” Risks related to our indebtedness could impact us to an even greater degree if such an acquisition is completed.

Expansion and construction projects are subject to risks, including delays and cost overruns, which could have an adverse impact on our financial condition and results of operations.

We have announced expansion and/or construction plans for our Lake Charles, Geismar and Calvert City complexes. Expansion and construction projects may be subject to delays or cost overruns, including delays or cost overruns resulting from any one or more of the following:

Significant cost overruns or delays could materially affect our financial condition and results of operations. Additionally, capital expenditures for these projects could materially exceed our planned capital expenditures.

Our level of debt could adversely affect our ability to operate our business.

As of December 31, 2011, we had total outstanding debt of $764.6 million, and our debt represented approximately 30% of our total capitalization. Our annual interest expense for 2011 was $51.0 million. Our level

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of debt and the limitations imposed on us by our existing or future debt agreements could have significant consequences on our business and future prospects, including the following:

To service our indebtedness, we will require a significant amount of cash. Our ability to generate cash depends on many factors beyond our control.

Our ability to make payments on and to refinance our indebtedness and to fund planned capital expenditures and pay cash dividends will depend on our ability to generate cash in the future. This is subject to general economic, financial, competitive, legislative, regulatory and other factors that are beyond our control.

Our business may not generate sufficient cash flow from operations, currently anticipated cost savings and operating improvements may not be realized on schedule and future borrowings may not be available to us under our credit facility in an amount sufficient to enable us to pay our indebtedness or to fund our other liquidity needs. We may need to refinance all or a portion of our indebtedness on or before maturity. In addition, we may not be able to refinance any of our indebtedness, including our credit facility and our senior notes, on commercially reasonable terms or at all.

Our credit facility and the indenture governing our senior notes impose significant operating and financial restrictions, which may prevent us from capitalizing on business opportunities and taking some actions.

Our credit facility and the indenture governing our senior notes impose significant operating and financial restrictions on us. These restrictions limit our ability to:

These limitations are subject to a number of important qualifications and exceptions. However, the effectiveness of these restrictions in the indenture governing our senior notes is currently suspended under the indenture because our senior notes are currently rated investment grade by at least two nationally recognized credit rating agencies.

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Our credit facility also requires us to maintain a minimum fixed charge coverage ratio or maintain a specified amount of availability under the credit facility to avoid certain restrictions. These covenants may adversely affect our ability to finance future business opportunities. A breach of any of these covenants could result in a default in respect of the related debt. If a default occurred, the relevant lenders could elect to declare the debt, together with accrued interest and other fees, to be immediately due and payable and proceed against any collateral securing that debt. In addition, any acceleration of debt under our credit facility will constitute a default under some of our other debt, including the indenture governing our senior notes.

Regulations concerning the transportation of hazardous chemicals and the security of chemical manufacturing facilities could result in higher operating costs.

Targets such as chemical manufacturing facilities may be at greater risk of terrorist attacks than other targets in the United States. As a result, the chemical industry responded to the issues surrounding the terrorist attacks of September 11, 2001 by starting initiatives relating to the security of chemicals industry facilities and the transportation of hazardous chemicals in the United States. Simultaneously, local, state and federal governments began a regulatory process that led to new regulations impacting the security of chemical plant locations and the transportation of hazardous chemicals. Our business or our customers’ businesses could be adversely affected because of the cost of complying with these regulations.

We may pursue acquisitions, dispositions and joint ventures and other transactions that may impact our results of operations and financial condition.

We seek opportunities to maximize efficiency and create stockholder value through various transactions. These transactions may include various domestic and international business combinations, purchases or sales of assets or contractual arrangements or joint ventures that are intended to result in the realization of synergies, the creation of efficiencies or the generation of cash to reduce debt. To the extent permitted under our credit facility, the indenture governing our senior notes and other debt agreements, some of these transactions may be financed by additional borrowings by us. Although these transactions are expected to yield longer-term benefits if the expected efficiencies and synergies of the transactions are realized, they could adversely affect our results of operations in the short term because of the costs associated with such transactions. Other transactions may advance future cash flows from some of our businesses, thereby yielding increased short-term liquidity, but consequently resulting in lower cash flows from these operations over the longer term. These transactions may not yield the business benefits, synergies or financial benefits anticipated by management.

We may have difficulties integrating the operations of acquired businesses.

If we are unable to integrate or to successfully manage businesses that we have acquired or that we may acquire in the future, our business, financial condition and results of operations could be adversely affected. We may not be able to realize the operating efficiencies, synergies, cost savings or other benefits expected from the acquisitions for a number of reasons, including the following:

The trading price of our common stock may negatively impact us.

Volatility in the capital and credit markets may cause downward pressure on stock prices and credit availability. The market value of our common stock is a factor in determining whether our goodwill is impaired. If the market value of our common stock declines significantly, it may result in an impairment of goodwill. A decline in the market value of our common stock could also negatively impact us in other ways, including making it more difficult for us to raise any equity capital.

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Failure to adequately protect critical data and technology systems could materially affect our operations.

Information technology system failures, network disruptions and breaches of data security could disrupt our operations by causing delays or cancellation of customer orders, impede the manufacture or shipment of products or cause standard business processes to become ineffective, resulting in the unintentional disclosure of information or damage to our reputation. While we have taken steps to address these concerns by implementing network security and internal control measures, there can be no assurance that a system failure, network disruption or data security breach will not have a material adverse effect on our business, financial condition, operating results or cash flow.

Our property insurance has only partial coverage for acts of terrorism and, in the event of terrorist attack, we could lose net sales and our facilities.

As a result of the terrorist attacks of September 11, 2001 and other events, our insurance carriers created certain exclusions for losses from terrorism from our property insurance policies. While separate terrorism insurance coverage is available, premiums for full coverage are very expensive, especially for chemical facilities, and the policies are subject to high deductibles. Available terrorism coverage typically excludes coverage for losses from acts of war and from acts of foreign governments as well as nuclear, biological and chemical attacks. We have determined that it is not economically prudent to obtain full terrorism insurance, especially given the significant risks that are not covered by such insurance. Where feasible we have secured some limited terrorism insurance coverage on our property where insurers have included it in their overall programs. In the event of a terrorist attack impacting one or more of our facilities, we could lose the net sales from the facilities and the facilities themselves, and could become liable for any contamination or for personal or property damage due to exposure to hazardous materials caused by any catastrophic release that may result from a terrorist attack.

We will be controlled by our principal stockholder and its affiliates as long as they own a majority of our common stock, and our other stockholders will be unable to affect the outcome of stockholder voting during that time. Our interests may conflict with those of the principal stockholder and its affiliates, and we may not be able to resolve these conflicts on terms possible in arms-length transactions.

As long as TTWF LP (the “principal stockholder”) and its affiliates (the “principal stockholder affiliates”) own a majority of our outstanding common stock, they will be able to exert significant control over us, and our other stockholders, by themselves, will not be able to affect the outcome of any stockholder vote. As a result, the principal stockholder, subject to any fiduciary duty owed to our minority stockholders under Delaware law, will be able to control all matters affecting us (some of which may present conflicts of interest), including:

The principal stockholder will be permitted to transfer a controlling interest in us without being required to offer our other stockholders the ability to participate or realize a premium for their shares of common stock. A sale of a controlling interest to a third party may adversely affect the market price of our common stock and our business and results of operations because the change in control may result in a change of management decisions and business policy. Because we have elected not to be subject to Section 203 of the General Corporation Law of the State of Delaware, the principal stockholder may find it easier to sell its controlling interest to a third party than if we had not so elected.

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In addition to any conflicts of interest that arise in the foregoing areas, our interests may conflict with those of the principal stockholder affiliates in a number of other areas, including:

We may not be able to resolve any potential conflicts with the principal stockholder affiliates, and even if we do, the resolution may be less favorable than if we were dealing with an unaffiliated party, particularly if the conflicts are resolved while we are controlled by the principal stockholder affiliates. Our amended and restated certificate of incorporation provides that the principal stockholder affiliates have no duty to refrain from engaging in activities or lines of business similar to ours and that the principal stockholder affiliates will not be liable to us or our stockholders for failing to present specified corporate opportunities to us.

Cautionary Statements about Forward Looking Statements

The Private Securities Litigation Reform Act of 1995 provides safe harbor provisions for forward-looking information. Certain of the statements contained in this Form 10-K are forward-looking statements. All statements, other than statements of historical facts, included in this Form 10-K that address activities, events or developments that we expect, project, believe or anticipate will or may occur in the future are forward-looking statements. Forward-looking statements can be identified by the use of words such as “believes,” “intends,” “may,” “should,” “could,” “anticipates,” “expected” or comparable terminology, or by discussions of strategies or trends. Although we believe that the expectations reflected in such forward-looking statements are reasonable, we cannot give any assurances that these expectations will prove to be correct. Forward-looking statements relate to matters such as:

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We have based these statements on assumptions and analyses in light of our experience and perception of historical trends, current conditions, expected future developments and other factors we believe were appropriate in the circumstances when the statements were made. Forward-looking statements by their nature involve substantial risks and uncertainties that could significantly impact expected results, and actual future results could differ materially from those described in such statements. While it is not possible to identify all factors, we continue to face many risks and uncertainties. Among the factors that could cause actual future results to differ materially are the risks and uncertainties discussed under “Risk Factors” and those described from time to time in our other filings with the SEC including, but not limited to, the following:

Many of such factors are beyond our ability to control or predict. Any of the factors, or a combination of these factors, could materially affect our future results of operations and the ultimate accuracy of the forward-looking statements. These forward-looking statements are not guarantees of our future performance, and our actual results and future developments may differ materially from those projected in the forward-looking statements. Management cautions against putting undue reliance on forward-looking statements or projecting any future results based on such statements or present or prior earnings levels. Every forward-looking statement speaks only as of the date of the particular statement, and we undertake no obligation to publicly update or revise any forward-looking statements.

None.

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Our manufacturing facilities and principal products are set forth below. Except as noted, we own each of these facilities.

Olefins

Our Lake Charles complex consists of three tracts on over 1,300 acres in Lake Charles, each within two miles of one another. The complex includes two ethylene plants, two polyethylene plants and a styrene monomer plant. The combined capacity of our two ethylene plants is approximately 2.5 billion pounds per year. The capacity of our two polyethylene plants is approximately 1.4 billion pounds per year and the capacity of our styrene plant is approximately 570 million pounds per year. Our newest polyethylene plant has two production units that use gas phase technology to manufacture both LLDPE and HDPE. In April 2011, we announced an expansion program to increase the ethane-based ethylene capacity of both of the ethylene units at our Lake Charles complex. We currently expect to complete the expansion of one of the two ethylene units by late 2012. The first cracker expansion is expected to increase ethylene capacity by approximately 230 – 240 million pounds annually, while also increasing feedstock flexibility. The additional capacity from this expansion is expected to provide ethylene for existing internal uses and may also be sold in the merchant market. In addition, we are currently evaluating expansion plans to increase the ethane-based ethylene capacity of the second ethylene unit at our Lake Charles complex.

Our Lake Charles complex includes a marine terminal that provides for worldwide shipping capabilities. The complex also is located near rail transportation facilities, which allows for efficient delivery of raw materials and prompt shipment of our products to customers. In addition, the complex is connected by pipeline systems to our ethylene feedstock sources in both Texas and Louisiana. Within the complex, our ethylene plants are connected by pipeline systems to our polyethylene and styrene plants.

Our Longview facility consists of three polyethylene plants, a specialty polyethylene wax plant, and a 200-mile ethylene pipeline that runs from Mont Belvieu to our Longview facility. The plants are located inside a large Eastman Chemical Company (“Eastman”) facility where Eastman produces a number of other chemical products. We can access ethylene to support our polyethylene operations either by purchasing ethylene from Eastman at the site or by transporting ethylene from our Lake Charles plant into the Gulf Coast grid and by transporting ethylene through our ethylene pipeline into our Longview facility. The technologies we use to produce polyethylene at Longview are similar to the technologies that we employ at Lake Charles. The Longview facility has a total capacity of 1.1 billion pounds per year.

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Vinyls

Our Calvert City complex is situated on 550 acres on the Tennessee River in Kentucky and includes an ethylene plant, a chlor-alkali plant, a VCM plant, a PVC plant and a large diameter PVC pipe plant. The capacity of our Calvert City ethylene plant is 450 million pounds per year and the capacity of our chlor-alkali plant is 550 million pounds of chlorine and 605 million pounds of caustic soda per year. Our chlorine plant utilizes efficient, state-of-the-art membrane technology. Our VCM plant has a capacity of 1.3 billion pounds per year and our Calvert City PVC plant has a capacity of 1.1 billion pounds per year. Our large diameter PVC pipe facility has a capacity of approximately 77 million pounds per year.

Our vinyls facility in Geismar is situated on 184 acres on the Mississippi River. The site includes a PVC plant with a capacity of 600 million pounds per year and a VCM plant with a capacity of 550 million pounds per year with related EDC capacity. In August 2010, we announced that we intend to proceed with the previously announced construction of a new chlor-alkali plant to be located at our vinyls manufacturing complex in Geismar. The new chlor-alkali unit is designed to produce up to 350,000 ECUs annually upon completion, bringing our total ECU capacity to 625,000 per year. The new plant will improve the vertical integration of our vinyls business from chlorine downstream into VCM and PVC, and increase caustic soda sales. The project is currently targeted for start-up in the second half of 2013.

As of February 17, 2012, we operated 10 building products plants, consisting of eight PVC pipe plants, and two profiles plants producing PVC fence, decking, windows and door profiles. The majority of our plants are strategically located near our Calvert City complex and serve customers throughout the middle United States. The combined capacity of our building product plants is 1.1 billion pounds per year.

In June 2011, we closed our Springfield PVC pipe facility, with an annual capacity of 90 million pounds.

We believe our current facilities and announced expansions are adequate to meet the requirements of our present and foreseeable future operations.

Headquarters

Our principal executive offices are located in Houston, Texas. Our office space is leased, at market rates, from an affiliate under a lease that expires on December 31, 2014. See Note 15 to the audited consolidated financial statements appearing elsewhere in this Form 10-K and “Certain Relationships and Related Transactions” in our proxy statement to be filed with the SEC within 120 days of December 31, 2011 pursuant to Regulation 14A with respect to our 2012 annual meeting of stockholders (the “Proxy Statement”).

In addition to the matters described under Item 1, “Business—Environmental and Other Regulation,” we are involved in various routine legal proceedings incidental to the conduct of our business. We do not believe that any of these routine legal proceedings will have a material adverse effect on our financial condition, results of operations or cash flows.

Not Applicable.

Executive Officers of the Registrant

James Chao (age 64). Mr. Chao has been our Chairman of the Board since July 2004 and became a director in June 2003. He previously served as our Vice Chairman of the Board since May 1996. Mr. Chao also has responsibility for the oversight of our Vinyls business. Mr. Chao has over 40 years of global experience in the chemical industry. In November 2010, Mr. Chao resigned as the Executive Chairman of Titan Chemicals Corp. Bhd., a position he held since June 2003. Prior to June 2003, he served as Titan’s Managing Director. He has served as a Special Assistant to the Chairman of China General Plastics Group and worked in various financial,

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managerial and technical positions at Mattel Incorporated, Developmental Bank of Singapore, Singapore Gulf Plastics Pte. Ltd. and Gulf Oil Corporation. Mr. Chao, along with his brother Albert Chao, assisted their father T.T. Chao in founding Westlake Chemical Corporation. Mr. Chao received his Bachelor of Science degree from the Massachusetts Institute of Technology and an M.B.A. from Columbia University.

Albert Chao (age 62). Mr. Chao has been our President since May 1996 and a director since June 2003. Mr. Chao has over 35 years of global experience in the chemical industry. In 1985, Mr. Chao assisted his father T.T. Chao and his brother James Chao in founding Westlake Chemical Corporation, where he served as Executive Vice President until he succeeded James as President. He has held positions in the Controller’s Group of Mobil Oil Corporation, in the Technical Department of Hercules Incorporated, in the Plastics Group of Gulf Oil Corporation and has served as Assistant to the Chairman of China General Plastics Group and Deputy Managing Director of a plastics fabrication business in Singapore. He was also previously a director of Titan Chemicals Corp. Bhd., a position he resigned from in November 2010. Mr. Chao received a bachelor’s degree from Brandeis University and an M.B.A. from Columbia University. Mr. Chao is a trustee emeritus of Rice University.

M. Steven Bender (age 55). Mr. Bender has been our Senior Vice President and Chief Financial Officer since February 2008. In addition, Mr. Bender has served as our Treasurer since July 2011, a position he also held from February 2008 until December 2010. From February 2007 to February 2008, Mr. Bender served as our Vice President, Chief Financial Officer and Treasurer and from June 2005 to February 2007, he served as our Vice President and Treasurer. From June 2002 until June 2005, Mr. Bender served as Vice President and Treasurer of KBR, Inc., and from 1996 to 2002 he held the position of Assistant Treasurer for Halliburton Company. Prior to that, he held various financial positions within that company. Additionally, he was employed by Texas Eastern Corporation for over a decade in a variety of increasingly responsible audit, finance and treasury positions. Mr. Bender received a Bachelor of Business Administration from Texas A&M University and an M.B.A. from Southern Methodist University. Mr. Bender is also a Certified Public Accountant.

Robert F. Buesinger (age 55). Mr. Buesinger has been our Senior Vice President, Vinyls since joining us in April 2010. Prior to joining us, Mr. Buesinger served as the General Manager and President of Chevron Phillips Chemical Company L.P.’s Performance Pipe Division from February 2010 to March 2010. From June 2008 to January 2010, Mr. Buesinger held the position of General Manager in the Alpha Olefins and Poly Alpha Olefins business of Chevron Phillips Chemical Company L.P. From April 2005 to May 2008, he served as the President and Managing Director of Chevron Phillips Singapore Chemicals Pte. Ltd. and Asia Region General Manager for Chevron Phillips Chemical Company L.P. Prior to that, he held various technical and sales management positions within that company. Mr. Buesinger holds a B.S. in Chemical Engineering from Tulane University.

Donald M. Condon, Jr. (age 62). Mr. Condon has been our Senior Vice President, Olefins and Corporate Business Development since July 2008. From July 2006 to July 2008, Mr. Condon was our Senior Vice President, Corporate Planning and Business Development. Prior to joining us, Mr. Condon served as the Managing Director of Titan Chemicals Corp. Bhd. from July 2003 to June 2006 and President & General Manager of Conoco Energy Ventures from 1998 until July 2003. He previously was employed by Conoco and Dupont in a variety of management and executive positions. In 2010, Mr. Condon was named a non-executive director of The Manitowoc Company, Inc. He was also previously a director of Titan Chemicals Corp. Bhd., a position he resigned from in November 2010. Mr. Condon holds a B.B.A. from the University of Wisconsin.

David R. Hansen (age 61). Mr. Hansen has been our Senior Vice President, Administration, since September 1999 and served as Vice President, Human Resources from 1993 to 1999. From August 2003 until July 2004 he was also our Secretary. Prior to joining us in 1990, Mr. Hansen served as Director of Human Resources & Administration for Agrico Chemical Company and held various human resources and administrative management positions within the Williams Companies. He has 30 years of administrative management experience in the oil, gas, energy, chemicals, pipeline, plastics and computer industries. He received his Bachelor of Science degree in Social Science from the University of Utah and has completed extensive graduate work toward an M.S. in Human Resources Management.

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Jeffrey L. Taylor (age 58). Mr. Taylor has been our Senior Vice President, Polyethylene since April 2008. From January 2003 to April 2008, Mr. Taylor served as our Vice President, Polyethylene. Mr. Taylor joined us in March 2002 as Manager, Polyethylene Marketing. Mr. Taylor joined us after a 25-year career with Chevron Phillips Chemical Company where he served as the Vice President, Polyethylene, Americas from 2000 to 2001 and Marketing Manager—Polyethylene from 1999 to 2000. During his career, he has held a variety of sales, marketing, operations and general management assignments. He is a graduate of the University of Delaware with a B.S. in Business Administration and a B.A. in Mathematics.

Andrew Kenner (age 47). Mr. Kenner has been our Vice President, Manufacturing since July 2008. Prior to joining us, Mr. Kenner served as Vice President and General Manager of Valero Energy Corporation’s Delaware City Refinery from September 2005 to July 2008. From August 2004 to September 2005, Mr. Kenner held the position of Vice President and General Manager of Valero’s Houston Refinery and from August 2003 to August 2004, he served as Operations Director for Valero’s Texas City Refinery. Mr. Kenner holds a B.S. in Aerospace Engineering from Texas A&M University and a M.S. in Chemical Engineering from the University of Texas at Austin.

George J. Mangieri (age 61). Mr. Mangieri has been our Vice President and Chief Accounting Officer since February 2007. From April 2000 to February 2007, he was Vice President and Controller. Prior to joining us, Mr. Mangieri served as Vice President and Controller of Zurn Industries, Inc. from 1998 to 2000. He previously was employed as Vice President and Controller for Imo Industries, Inc. in New Jersey, and spent over 10 years in public accounting with Ernst & Young LLP, where he served as Senior Manager. He received his Bachelor of Science degree from Monmouth College and is a Certified Public Accountant.

Stephen Wallace (age 65). Mr. Wallace has been our Vice President and General Counsel since December 2003 and our Secretary since July 2004. He began his legal career over 25 years ago at the law firm of Baker Botts L.L.P., which he left as a partner in 1993. He subsequently held senior corporate legal positions with Transworld Oil U.S.A., Inc. (1993-1996; 2002-2003), Oman Oil Company Ltd. (1996-1997), and Enron Global Exploration & Production Inc. and its affiliates (1997-2002). Mr. Wallace holds a B.A. from Rice University and a Ph.D. from Cornell University in linguistics, and received his J.D. from the University of Houston.

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PART II

Price Range of Common Stock

As of February 17, 2012, there were 54 holders of record of our common stock. Our common stock is listed on the New York Stock Exchange under the symbol “WLK.” Set forth below are the high and low closing prices for our common stock, as reported on the New York Stock Exchange composite tape for the periods indicated and the cash dividends declared in these periods.

Our credit facility and the indenture governing our senior notes restrict our ability to pay dividends or other distributions on our equity securities. However, the effectiveness of these restrictions in the indenture governing the senior notes is currently suspended because the senior notes are currently rated investment grade by at least two nationally recognized credit rating agencies. See “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources—Debt” for additional information.

Issuer Purchases of Equity Securities

The following table provides information on our purchase of equity securities during the quarter ended December 31, 2011:

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Equity Compensation Plan Information

Securities authorized for issuance under equity compensation plans are as follows:

Other information regarding our equity compensation plans is set forth in the section entitled “Executive Compensation” in our Proxy Statement, which information is incorporated herein by reference.

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Reconciliation of EBITDA to Net Income (Loss) and

to Cash Flow from Operating Activities

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Overview

We are a vertically integrated manufacturer and marketer of petrochemicals, polymers and fabricated building products. Our two principal business segments are Olefins and Vinyls. We use the majority of our internally-produced basic chemicals to produce higher value-added chemicals and building products.

Consumption of the basic chemicals that we manufacture in the commodity portions of our olefins and vinyls processes has increased significantly over the past 25 years. Our olefins and vinyls products are some of the most widely used chemicals in the world and are upgraded into a wide variety of higher value-added chemical products used in many end-markets. Petrochemicals are typically manufactured in large volume by a number of different producers using widely available technologies. The petrochemical industry exhibits cyclical commodity characteristics, and margins are influenced by changes in the balance between supply and demand and the resulting operating rates, the level of general economic activity and the price of raw materials. The cycle is generally characterized by periods of tight supply, leading to high operating rates and margins, followed by a decline in operating rates and margins primarily as a result of significant capacity additions. Due to the significant size of new plants, capacity additions are built in large increments and typically require several years of demand growth to be absorbed.

Beginning in 2009 and continuing through 2011, a cost advantage for natural gas-based ethylene producers over naphtha-based ethylene producers allowed a strong export market and higher margins for North American chemical producers, including Westlake. Increased global demand for polyethylene in 2010 and 2011 resulted in increased sales volumes and improved operating margins and cash flow for our Olefins segment. However, some olefins industry consultants predict that significant increases in worldwide ethylene and ethylene derivative capacity, which have occurred over the past four years, primarily in the Middle East and Asia, may continue for the next several years. As a result, our Olefins segment operating margins may be negatively impacted.

Weakness in the U.S. construction markets, which began in the third quarter of 2006, and the subsequent budgetary constraints in municipal spending, have contributed to lower domestic demand for our vinyls products. In addition, increases in feedstock costs, combined with the industry’s inability to sufficiently raise domestic prices for PVC resin and building products in order to offset cost increases, significantly impacted our Vinyls segment’s operating results in 2010 and 2011. Since late 2010, the PVC industry has experienced an increase in PVC resin export demand, driven largely by more competitive ethylene and energy cost positions in North America. In addition, PVC resin capacity in Japan was negatively impacted for a period following the tsunami in early 2011, which tightened global PVC resin availability. As a consequence, prices and margins for domestic PVC resin and building products improved in 2011. Looking forward, our Vinyls segment operating rates and margins may continue to be negatively impacted by the slow recovery of U.S. construction markets and North American PVC capacity additions.

While the economic environment continues to be challenging for our customers, we believe our customer base remains generally healthy. As we continue to manage our business in this environment, including the slowdown in construction activity, we have taken steps designed to address the changes in demand and margins in our Vinyls segment and its resulting impact on our operations by matching production with sales demand and continuing to operate our plants in an efficient manner. We continue to monitor our cost management programs and discretionary capital spending. The impact of the global economic environment has been challenging to our business and, depending on the performance of the economy in 2012 and beyond, could have a negative effect on our financial condition, results of operations or cash flows.

We purchase significant amounts of ethane and propane feedstock, natural gas, ethylene, chlorine and salt from external suppliers for use in production of basic chemicals in the olefins and vinyls chains. We also purchase significant amounts of electricity to supply the energy required in our production processes. While we have agreements providing for the supply of ethane and propane feedstocks, natural gas, ethylene, chlorine, salt and electricity, the contractual prices for these raw materials and energy vary with market conditions and may be highly volatile. Factors that have caused volatility in our raw material prices in the past and which may do so in the future include:

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Significant volatility in raw material costs tends to put pressure on product margins as sales price increases could lag behind raw material cost increases. Conversely, when raw material costs decrease, customers may seek immediate relief in the form of lower sales prices. We currently use derivative instruments to reduce price volatility risk on feedstock commodities and lower overall costs. Normally, there is a pricing relationship between a commodity that we process and the feedstock from which it is derived. When this pricing relationship deviates from historical norms, we have from time to time entered into derivative instruments and physical positions in an attempt to take advantage of this relationship.

Our historical results have been significantly affected by our plant production capacity, our efficient use of the capacity and our ability to increase our capacity. Since our inception, we have followed a disciplined growth strategy that focuses on plant acquisitions, new plant construction and internal expansion. We evaluate each expansion project on the basis of its ability to produce sustained returns in excess of our cost of capital and its ability to improve efficiency or reduce operating costs.

As noted above in Item 1A, “Risk Factors,” we are subject to extensive environmental regulations, which may impose significant additional costs on our operations in the future. Further, current concern about GHG emissions and their possible effects on climate change has led to the enactment of regulations, and to proposed legislation and additional regulations that could affect us in the form of increased cost of feedstocks and fuel, other increased costs of production and decreased demand for our products. While we do not expect any of these enactments or proposals to have a material adverse effect on us in the near term, we cannot predict the longer-term effect of any of these regulations or proposals on our future financial condition, results of operations or cash flows.

Recent Developments

On January 13, 2012, we announced that we submitted a proposal to Georgia Gulf to acquire all of the outstanding shares of Georgia Gulf for $30.00 per share in cash, or a total of approximately $1.1 billion. Our proposal was not subject to financing conditions. Georgia Gulf rejected our proposal on January 16, 2012 and adopted a stockholder rights plan. On February 1, 2012, we announced that we were increasing our offer to $35.00 per share in cash, or a total of approximately $1.2 billion, with the possibility of offering our common stock as part of the offer consideration. On that date, Georgia Gulf also publicly rejected our increased offer. As of February 17, 2012, we held shares representing approximately 4.8% of the outstanding shares of common stock of Georgia Gulf.

In December 2011, we announced plans to perform a major modification of the ethylene production facility at our Calvert City complex. The modification is expected to reduce costs and improve operating efficiency and energy consumption. We currently expect the modification to be completed by mid-2013. In addition, we are currently evaluating conversion from propane to ethane feedstock for our ethylene production facility at Calvert City in order to capitalize on available low cost ethane and other “light” feedstock being developed in North America.

In August 2011, our Board of Directors authorized a stock repurchase program totaling $100.0 million. Purchases under this program may be made either through the open market or in privately negotiated transactions. Decisions regarding the amount and the timing of purchases under the program will be influenced by our cash on hand, our cash flow from operations, general market conditions and other factors. The program may be discontinued by our Board of Directors at any time.

In June 2011, as a result of excess capacity in the PVC pipe market and in an effort to reduce costs and optimize production operations, we closed our Springfield PVC pipe facility. We recorded asset impairment, severance and other costs related to the pipe facility closure of $3.4 million.

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In May 2011, we completed a planned major maintenance activity, or turnaround, at our Calvert City facility. The ethylene, VCM and PVC units were shut down for a total of 16 days each to perform the planned major maintenance activities. The chlor-alkali unit was down for a shorter period.

In April 2011, one of the ethylene units at our Lake Charles facility experienced an unscheduled shut down caused by a weather related power supply failure from a third party power provider. We restarted the ethylene unit three days later but operated the unit at reduced capacity, until we returned it to normal operations in late May. In addition to the lost production resulting from the outage, we incurred repair costs and unabsorbed fixed manufacturing costs which negatively impacted income from operations.

In April 2011, we announced an expansion program to increase the ethane-based ethylene capacity of both of the ethylene units at our Lake Charles complex. We currently expect to complete the expansion of one of the two ethylene units by late 2012. The first cracker expansion is expected to increase ethylene capacity by approximately 230 – 240 million pounds annually, while also increasing feedstock flexibility. The additional capacity from this expansion is expected to provide ethylene for existing internal uses and may also be sold in the merchant market. We expect this project will be funded with cash on hand, cash flow from operations, the net proceeds from the revenue bonds of the Louisiana Local Government Environmental Facility and Development Authority (the “Authority”), a political subdivision of the State of Louisiana, and if necessary, our revolving credit facility and other external financing. In addition, we are currently evaluating expansion plans to increase the ethane-based ethylene capacity of the second ethylene unit at our Lake Charles complex.

In August 2010, we announced that we intend to proceed with the previously announced construction of a new chlor-alkali plant to be located at our vinyls manufacturing complex in Geismar. In December 2011, we announced that we were increasing the planned capacity of the chlor-alkali plant. The new chlor-alkali unit is designed to produce up to 350,000 ECUs annually upon completion, bringing our total ECU capacity to 625,000 per year. The new plant will improve the vertical integration of our vinyls business from chlorine downstream into VCM and PVC and increase caustic soda sales. The project is currently targeted for start-up in the second half of 2013. We expect this project will be funded with cash on hand, cash flow from operations, the net proceeds from the revenue bonds of the Authority, and if necessary, our revolving credit facility and other external financing.

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Results of Operations

Segment Data