Occidental Chemical Corporation Corporate Office 5005 LBJ Freeway, Dallas, TX 75244-6119 P.O. Box 809050, Dallas, TX 75380-9050
972/404-3800 September 24, 2010

Via Electronic Mail

Jodi Howard Environmental Engineer
U.S. EPA - Office of Air Q uality 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—Clarificat ion of PVC Resin Concentration Data Supplementing Submissions in Response to EPA’s Section 114 Request

Dear Ms. Howard:

This letter is intended to clarify that t he resin concentration data generated by Oxy Vinyls, LP (“OxyVinyls”) pursuant to the abov e-referenced rulemaking was incorporated into the concentration data spreadsheet submi tted to the Agency by the Vinyl Institute (“VI”) on September 16, 2010. The data in the spreadsheet constitutes analytical results of polyvinyl chloride (“PVC”) resin samples collected in response to the Agency’s August 21, 2009, and September 21, 2009, in formation collection requests under the authority of Section 114 of the Clean Air Act (hereinafter “114 Request”). This PVC resin sampling and analysis program was approved by the Agency on November 02, 2009, for our Pasadena, TX and Pedricktown, NJ facilities and November 19 and 23, 2009, for our Deer Park, TX facility. This data identified and quant ified hazardous air pollutants that may be emitted from PVC resin processing at each of the three OxyVinyls PVC facilities. As described in our three EPA-approved sampling plans (Deer Park, TX Resin Sampling and Analysis Plan , Pasadena, TX Resin Sampling Plan

, and Pedricktown, NJ Resin Sampling and Misc. Fugitive Source Plan) , the resin analytical results (or concentrations) were used to calculate estimated quantitative mass emissions for HAPs. The results were reported on the EPA 30-Day Resin Sampling Spreadsheets for Stripper and Dryer Outlets, wh ich were initially submitted on March 1, 2010, followed by a revised set of Resin Sampling Spreadsheets on April 21, 2010, which, at that time, also included a CB I submission of separate daily spreadsheetsOccidental Chemical Corporation Corporate Office 5005 LBJ Freeway, Dallas, TX 75244-6119 P.O. Box 809050, Dallas, TX 75380-9050
972/404-3800 showing analytical results for HAPs conc entrations, and HAP loadings calculated from

those concentrations.

Upon reviewing the 114 Request data pub lished on the Agency’s website, it quickly became apparent that inconsistent me thods had been used to convert the resin

concentration results into estimated mass em issions. For example, we understand that some facilities used production volume from t he entire plant to calc ulate the quantitative mass emissions, while OxyVinyls used only the volume from the production lines being sampled. Each of our three PVC plants esti mates production volume differently. Rather than evaluating the accuracy of each plant’s me thod of determination of daily production and the impact of this on mass emission estimate s, use of laboratory concentration data seems like the more consistent approach. As VI indicated in its September 16, 2010 submission, there were other inconsistenc ies in the emission calculations stemming from the varying nature of sampling and testing plans approved by the Agency and assumptions made by each company in performing mass balance calculations.

Data provided by OxyVinyls in March and April of 2010 previously provided resin concentration data for each day of our 30 day sampling program, as well as an example

to illustrate our mass calculation me thodology. The only change from the HAP concentration data in the previously submitt ed daily spreadsheets that are now reflected

in the VI concentration database is described below:

Upon review of several laboratory reports, it was determined that m any of the reported non-detectable concentrations in our previous submissions were actually lab Reporting Levels (RLs), not non-detection (ND) levels, which were incorrectly flagged with ‘U’* qualifiers. This occurred because the labor atory had not completed an MDL study for the selected ion monitoring (SIM) mode of oper ation of the mass spectrometer, used to enhance detection limits in Method 8260, until la te in the project. Thus, the newly determined MDLs did not appear on the lab r eports, and the RLs that were on the lab reports were inadvertently reported as ‘U’ flagged detection limits in the daily concentration spreadsheets previously to the Agency. This error was first detected only a few weeks ago, so OxyVinyls made the appropriate changes in the newly compiled Vinyl Institute concentration spreadsheet, but has not yet made those changes in the daily spreadsheets previously submitted in Ap ril 2010. The changes that were made to the Vinyl Institute spreadsheet were only to replace incorrect U flags with RL flags so

that the data user knows that the number in the adjacent colu mn is a reporting limit, not a detection limit. OxyVinyls is in the proc ess of obtaining correct MDL values for each sample and each HAP analyte fr om the laboratory via revis ed lab report pages, so that the Vinyl Institute spreadsheet can be updat ed with correct numerical values for

* U - Not present at or above the associated valueOccidental Chemical Corporation Corporate Office 5005 LBJ Freeway, Dallas, TX 75244-6119 P.O. Box 809050, Dallas, TX 75380-9050
972/404-3800 detection limits, at which time the RL fl ags will be changed to correct U flags. The impact of these changes on our reported mass va lues is not expected to be significant. However, since we do not know how EPA ha s used the OxyVinyls data set, we can not be certain of the potential significance.

Accordingly, OxyVinyls believes that the resin data submitted by VI, which is the
actual measured concentration data before t he application of any mass calculations, presents the best available set of data generated from our study, and is the best set of data from which to develop a maximum achi evable control technology standard for the PVC and Copolymer production category.

In closing, OxyVinyls wishes again to emphasize that the spreadsheet submission does not amend any data previously submitted to the Agency in response to its 114 Request. Rather it is the measured data that formed the basis of the emissions estimates provided in the EPA 30-Day Resi n Sampling spreadsheets. The OxyVinyls resin sampling data was developed in acco rdance with the approach set out in its EPAapproved sampling plan and it was not until VI members examined this data collectively

that the inconsistencies in reporting became apparent.

Please do not hesitate to contact me at 972-404-3209 if you have any questions

or concerns.

Respectfully,

Barry Christensen Occidental Chemical Corp. Manager Air Quality