Page 1 of 5

1737 King Street, Suite 390 ●Alexandria, VA 22314 ●(571) 970-3359●Fax (571) 970-3271 

www.vinylinfo.org ●www.vinylindesign.com

November 2, 2009

Ms. Jodi Howard

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

RE: PVC MACT Resin Testing Program Pursuant to Section 114 Letters, 

 Vinyl Institute (VI) Working Group 

Dear Ms. Howard,

The Vinyl Institute’s Working Group on PVC MACT Testing Requirements recently met 

via teleconference to discuss HAP testing methods specific to PVC resin, and timing 

requirements of the U.S. Environmental Protection Agency’s (EPA’s) 42 U.S.C. § 7414 

information collection request (hereinafter, “114 Request”). PVC resin testing using 

EPA SW-846 methods presents some unique analytical challenges. Therefore, we are 

presenting this analytical response plan to inform EPA of the issues and how we will 

address them.

Specifically, PVC resin testing using EPA SW-846 methods presents challenges 

because:

(1) certain hazardous air pollutants (HAPs) are not amenable to analysis in PVC resin,

(2) the slurry stripper discharge samples need to be separated for analysis into two 

separate phases (water and resin), and

(3) PVC resin particles tend to clump together during certain standard sample extraction

procedures.
Page 2 of 5

1737 King Street, Suite 390 ●Alexandria, VA 22314 ●(571) 970-3359●Fax (571) 970-3271 

www.vinylinfo.org ●www.vinylindesign.com

We believe these unique challenges can be addressed via allowable modifications to 

sample preparation steps, but full validation of these modified methods can not be 

performed ahead of time, due to time constraints prescribed by the February 28, 2010

reporting deadline in the 114 Request.

The known analytical challenges and planned modifications are more fully described 

below. Although there is not enough time to fully validate all of these modifications, we 

believe the solutions presented represent the best efforts of the member companies to 

properly balance analytical quality assurance requirements with the 114 Request time 

constraints. If the EPA has comments, suggestions or specific guidance regarding 

these challenges and the path forward, we would be happy to receive and discuss 

them. Since at least two member companies plan to begin PVC resin testing in early 

November, we would appreciate receiving EPA’s comments, on an expedited basis.

1) SW-846 test methods are not appropriate for analyzing PVC resin for certain 

specific HAPs

Certain HAPs targeted for testing by the 114 Request, specifically hydrochloric acid 

(HCl) and Chlorine gas (Cl2), do not appear on the analyte lists for the SW-846 test 

methods. These two HAPs can not readily be separated or extracted from solid PVC 

resin as molecular HCl or CL2 for analysis, due to their reactivity.

HCl extracted into water would immediately ionize to H+ and Cl-. A pH test of a water 

extract could be done, but would only measure hydrogen ion concentration (from all 

extracted acidic components), not molecular HCl. Molecular HCl is a minor impurity in 

vinyl chloride monomer (VCM), and would partition almost exclusively to the aqueous 

phase (as ionized H+ and Cl-) in the PVC reactor. Therefore, this minor component 

would exit the PVC dewatering and drying process as either ionized H+ and Cl- with the 

separated water, or be present on the resin particles as small quantities of chloride salts 

(e.g. NaCl or common table salt), not as molecular HCl.

Similarly, molecular Cl2 cannot be analytically determined in solid PVC resin either. The 

chlorine molecule would react (disassociate) in a water extract, and establish an 

equilibrium between hypochlorous acid, hypochlorite ion and the chlorine molecule. A 
Page 3 of 5

1737 King Street, Suite 390 ●Alexandria, VA 22314 ●(571) 970-3359●Fax (571) 970-3271 

www.vinylinfo.org ●www.vinylindesign.com

total residual chlorine test could be performed, but would measure many more species 

than molecular chlorine. In any case, we do not expect molecular chlorine (Cl2) to be 

present in PVC resins, and so it could not be emitted as a HAP.

 Based on the above discussion, neither hydrochloric acid, nor chlorine, are expected 

to be present in the resin as it leaves the slurry stripper. There is, therefore, no need to 

attempt development of special techniques to analyze for them at trace levels in the 

resin slurry or the final resin product. They will not be included in the testing program, 

since they are not expected to be present in the PVC resin.

Other potential HAPs, such as butadiene and vinyl bromide, are also not listed as 

analytes in SW-846 methods, but may be amenable to quantitative analysis via the 

development of a calibration curve, once standards are purchased (if available). If an

unknown peak is identified as a significant HAP by mass spectra (Methods 8260 and 

8270), most companies and their laboratories will make best efforts to obtain standards 

and prepare calibration curves for use in subsequent analyses. 

2) Dual phase slurry stripper discharge

The slurry stripper discharge (SSD) is normally composed of 20% or more PVC resin in 

an aqueous matrix, which requires that the solid phase (resin) be separated from the 

liquid phase, to ensure sample integrity is maintained for application of subsequent SW846 methods. This separation results in the need to perform two analyses (on the liquid 

and the solid) for each HAP method, the results of which will then be mathematically 

combined and expressed on a dry weight PVC resin basis.

There are several ways to accomplish the separation and analysis of the two phases of 

the SSD samples. Due to time constraints resulting from the reporting schedule in the 

114 Request, a single industry-wide, VI sponsored validation program can not be 

completed before resin sampling begins. Each company will be responsible for 

independently choosing sample handling, extraction and analytical methods for use in 

their resin sampling program. Obviously, some variability may be introduced in the final 

results, given the various methodological approaches available to each company. 

Given the large data sets to be provided by VI members, however, as well as other
Page 4 of 5

1737 King Street, Suite 390 ●Alexandria, VA 22314 ●(571) 970-3359●Fax (571) 970-3271 

www.vinylinfo.org ●www.vinylindesign.com

inherent variations in the calculation of HAP emission rates, we would not expect the 

sampling and analytical variations to adversely impact the resin testing program as a 

whole. 

3) Modifications to extraction of HAPs from PVC resin

PVC resin tends to swell in the presence of organic solvents used for extraction under

SW-846 methods. This is a particular concern when using solvent extraction 

procedures prior to semi-volatile analyses via EPA Method 8270. Another concern is 

that PVC resin, near its glass transition temperature, will clump together in sample 

preparation procedures, especially those which heat the sample at or near the PVC 

softening point. Thus, for solvent extraction procedures, it may be necessary to 

disperse the PVC resin particles in a granular matrix, for example, clean sand or glass 

beads, before extraction.

To the extent that HAP chemicals are dispersed inside the PVC matrix, extraction times 

may need to be extended to ensure acceptable recovery from the PVC matrix. Due to 

time constraints for the PVC MACT resin testing program, selecting and validating PVC 

resin extraction procedures ahead of time is not feasible. Instead, the VI Work Group 

members propose that laboratories retained by VI member facilities will perform 

additional preliminary and ongoing quality assurance (QA) checks to ensure the chosen 

sample preparation technique(s) maintain the high surface area of the PVC resin 

particles (no clumping or melting together) and provide adequate solvent extraction 

duration. The Vinyl Institute members have used such method modifications before, 

during method development and validation studies on PVC resins. Whichever 

modifications to extraction techniques and associated QA are adopted for use by 

individual companies, they will be described in the final PVC resin reports to be 

submitted to EPA by February 28, 2010.

The industry looks forward to receiving any Agency comments, suggestions, or specific 

guidance on our planned path forward. Since two companies are planning to begin 

PVC resin testing in early November, we would appreciate an expedited response. 

Please do not hesitate to contact me with any questions or comments.
Page 5 of 5

1737 King Street, Suite 390 ●Alexandria, VA 22314 ●(571) 970-3359●Fax (571) 970-3271 

www.vinylinfo.org ●www.vinylindesign.com

Sincerely, 

Richard P. Krock

Technical Director

e-mail: rkrock@vinylinfo.org

phone: 571-970-3392

cell: 571-216-4474