Westlake Center

2801 Post Oak Blvd.

Suite 600

Houston, Texas 77056

Tel: 713/960-9111

April 20, 2011

VIA ELECTRONIC AND FIRST CLASS MAIL

Jodi Howard

Environmental Engineer

U.S. EPA - Office of Air Quality Planning and Standards

Sector Policies and Program Divisions

Coatings and Chemicals Group

Mail Code: E143-01

Research Triangle Park, NC 27711

Howard.Jodi@epamail.epa.gov

Re: PVC MACT Rulemaking—Clarification of PVC Resin Concentration Data 

Supplementing Submissions in Response to EPA’s Section 114 Request

Dear Ms. Howard:

This letter is intended to clarify the purpose of resin concentration data provided on behalf of 

Westlake Chemical Corporation (“Westlake”) in the concentration data spreadsheet submitted to the EPA

on September 16, 2010, by The Vinyl Institute (“VI”). The data in the spreadsheet constitutes analytical 

results of polyvinyl chloride (PVC) resin sampling collected in response to the EPA’s August 21, 2009 

information collection request under the authority of Section 114 of the Clean Air Act (CAA) (hereinafter 

“114 Request”). The PVC resin sampling and analysis plans for the Westlake PVC facilities in Calvert 

City, KY and Geismar, LA were approved by the EPA on October 30, 2009 and sought to identify and 

quantify hazardous air pollutants (HAPs) from each of Westlake’s two PVC resin manufacturing plants. 

As described in each of our EPA-approved Sampling and Analysis Plans, the resin analytical results (or 

concentrations) were used to calculate estimated quantitative mass emissions for HAPs and reported on 

the EPA 30-Day Resin Sampling Spreadsheets for Stripper and Dryer Outlets.

Upon reviewing the 114 Request data published on the EPA’s website, it quickly became 

apparent to The VI and Westlake that inconsistent methods had been used to convert the resin analytical 

results into estimated mass emissions among the VI member companies. For example, we understand 

that some facilities used production volume from the entire plant to calculate the quantitative mass 

emissions while others used only the volume from the production lines being sampled. As the VI 

indicated in its September 16, 2010 submission, there were other inconsistencies in the emissions 

calculations stemming from the varying sampling and testing plans approved by the EPA. Accordingly, 

Westlake submits that the concentration data submitted by VI in the spreadsheet is the actual measured 

data before the application of any mass calculations, and presents the most uniform, comparable, best and 

accurate data set from which to develop a maximum achievable control technology standard for the PVC 

and Copolymer production category.
Jodi Howard

Environmental Engineer

U.S. EPA - Office of Air Quality Planning and Standards

April 20, 2011

Page Two

In closing, Westlake wishes again to emphasize that the spreadsheet submission does not amend 

any data previously submitted to the EPA in response to its 114 Request. Rather, it is the actual measured 

concentration data that formed the basis of the emissions estimate provided in the EPA 30-Day Resin 

Sampling spreadsheets. The resin sampling data from Westlake was developed in accordance with the 

approach set out in its EPA-approved sampling plan, and it was not until the VI members examined this 

data collectively that the inconsistencies in reporting methodologies became apparent.

Please do not hesitate to contact me if you have any questions or concerns via email at 

kbloomer@westlake.com, or via telephone at 713-585-2946.

Sincerely,

Kevin Bloomer

Sr. Environmental Engineer

Westlake Chemical Corporation