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Via Electronic Mail and Certified Mail

June 5, 2015

Paul Lewis

Chief, Chemical Information and Testing Branch

Office of Pollution Prevention and Toxics

USEPA Headquarters

William Jefferson Clinton Building

1200 Pennsylvania Ave., N.W.

Washington, DC 20460

Re: Follow Up to May 20, 2015 Teleconference

Testing Consent Order for Octamethylcyclotetrasiloxane (D4) CASRN 556-67-2

40 C.F.R. 799.5000; EPA-HQ-OPPT-2012-0209

Dear Paul:

This letter follows the May 20, 2015, conference call (May 20th Call) between the Silicones Environmental, Health, 

and Safety Center (SEHSC) and the U.S. Environmental Protection Agency (EPA or Agency) regarding the 

selection of five wastewater treatment plants (WWTP) to meet the requirements of Appendix 2 to the D4 

Enforceable Consent Agreement (ECA). SEHSC, as principal test sponsor for the ECA signatory companies, 

believes that the Study Plan and supporting materials provided to the Agency demonstrate that the WWTP 

locations proposed for sampling meet the ECA criteria set out in Appendix 2 to the ECA. Accordingly, we trust that 

EPA will accept those sites and approve the Study Plan and QAPP as soon as possible so that testing program can 

move forward at the four direct discharge sites, the five “Primarily Non-Industrial” WWTPs, and the five “Indirect 

Discharge” WWTPs proposed for sampling. 

During the May 20th Call and via letter dated May 13, 20151, EPA expressed concern regarding whether certain of 

the WWTPs proposed for sampling met the ECA criteria for “Indirect Discharge Sites.” Specifically, the Agency 

questioned whether each Indirect Discharge WWTP proposed for sampling is receiving wastewater from a “known” 

D4 processor/formulator. 

According to the Appendix 2 to the ECA, for the Indirect Discharge WWTPs:

All wastewater treatment sites selected for monitoring must be currently processing wastewater from one or 

more industrial sites known to be a D4 processor or formulator as documented through industrial user 

surveys or by other readily available information. The WWTP influent shall reasonably be expected to 

contain D4 based on industrial user surveys or other readily available information.

As SEHSC and the Agency have discussed on numerous occasions, the process for identifying, qualifying, and 

securing the agreement of the WWTPs to participate in this program has been challenging and time-consuming. 

SEHSC and the ECA signatory companies do not own, operate, or control the WWTPs. The WWTP 

owners/operators are not subject to the ECA and are under no obligation to participate in the program. Likewise, 

the indirect dischargers that send their wastewater to the WWTPs are also not subject to the ECA. Furthermore, in 

 

1 May 13, 2015 Letter from Maria Doa, Ph.D., Director, Chemical Control Division, U.S. Environmental Protection Agency to Karluss 

Thomas, Senior Director, Silicones Environmental, Health, and Safety Center.
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addition to the criteria noted above, Appendix 2 to the ECA also specifies that the WWTPs must use activated 

sludge for treatment and employ no other form of additional treatment other than secondary clarification/disinfection 

absent EPA agreement; the WWTPs may only release to riverine systems and should have effluent discharge rates 

that are relatively large when compared to the receiving water body (low dilution); and the sites should be in 

different regions of the country. Together, these factors greatly limit the pool of potential sampling locations. 

In light of the above considerations, SEHSC’s contractor engaged in an intensive iterative process to review, 

qualify, and secure the participation of WWTPs for the program. This process was described in § 2.5.1.2 of the 

Draft Study Plan (and in prior meetings/teleconferences with the Agency). As follow up to this process and in 

response to EPA’s request, a survey instrument was sent to indirect dischargers associated with each proposed 

WWTP to obtain additional data to further validate that the WWTPs met the ECA criteria. Responses to those 

surveys, which have been provided to the Agency, bolster our contention that each proposed WWTP is receiving 

wastewater from one or more industrial sites “known” to be a D4 processor or formulator. During the May 20th Call, 

we reviewed the responses for each site and discussed how those responses specifically confirm each WWTP’s 

eligibility.2 

It bears noting that the ECA anticipates that it may prove challenging to “know” whether an indirect discharger not 

subject to the ECA is indeed a D4 processor or formulator. Hence, the inclusion of the provision that this may be 

documented “through industrial user surveys or by other readily available information” and that “WWTP influent 

shall reasonably be expected to contain D4 based on industrial user surveys or other readily available information.” 

In this case, survey results, SIC code analysis, and industry knowledge (including, for example, a detailed 

description of silicone polymers and their role/usage in various industries) have all been provided to substantiate 

the proposed WWTPs. 

During the May 20th Call, EPA also raised concerns regarding the scope and meaning of “process” as applied to 

site selection for the Testing Program. Specifically, EPA questioned whether certain of the indirect dischargers 

associated with the WWTPs proposed for sampling may be considered to be a “processor” as defined by the Toxic 

Substances Control Act (TSCA)3if a site were “only” processing polymers or other materials containing D4. 

We note that the ECA does not define “processor” or “process.” However, as noted in our May 20, 2015 slide deck 

(and referenced in EPA’ May 13, 2015 letter), TSCA defines the terms quite broadly:

(10) The term “process” means the preparation of a chemical substance or mixture, after its manufacture, 

for distribution in commerce— 

(A) in the same form or physical state as, or in a different form or physical state from, that in which 

it was received by the person so preparing such substance or mixture, or 

(B) as part of an article containing the chemical substance or mixture. 

(11) The term “processor” means any person who processes a chemical substance or mixture.4

Moreover, as we noted during the May 20th Call, the Agency has defined the term “process” or “processor” in a 

consistent manner in numerous places throughout its TSCA-implementing regulations:

Process means to process for commercial purposes.

Process for commercial purposes means the preparation of a chemical substance or mixture after its 

manufacture for distribution in commerce with the purpose of obtaining an immediate or eventual 

commercial advantage for the processor. Processing of any amount of a chemical substance or mixture is 

included in this definition. If a chemical substance or mixture containing impurities is processed for 

commercial purposes, then the impurities also are processed for commercial purposes.

Processor means any person who processes a chemical substance or mixture.5 

 

2

For the teleconference, we provided a slide deck that summarizes the analysis for each site. 

3

15 U.S.C. §§ 2601 – 2692.

4

15 U.S.C. § 2602.

5

40 C.F.R. § 704.3. Similar definitions appear, for example, in 40 C.F.R. §§ 712.3(m), 716.3, 717.3(g), and 721.3. 
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As we highlighted during the May 20th Call, this definition would squarely encompass the indirect discharge sites 

associated with the WWTPs proposed for sampling under Appendix 2 to the ECA. 

We observe that in instances in which the Agency has decided to limit the scope of the definition of “process” so 

that a particular regulatory requirement was not applicable to a party that solely processes a given chemical 

substance as an impurity, it has done so explicitly in the corresponding rulemaking.6 The ECA does not contain 

any such qualification or limitation and we believe strongly that the proposed WWTPs satisfy the ECA criteria. We 

believe that their inclusion is consistent with the purposes of the Testing Program, particularly given that those sites 

reflect how D4 is being processed at most industrial facilities throughout the U.S.7 

As we noted during the May 20th Call and in our prior discussions, delays in approving the Study Plan and QAPP 

will greatly impact the timing for completion of the Testing Program due to the limited availability of sampling 

windows at the various locations. SEHSC and the Signatory Companies to the ECA stand ready to move forward 

with the actual sampling phase of the Testing Program and look forward to the Agency’s approval of the Study Plan 

and QAPP so that mobilization activities can commence. 

Please do not hesitate to contact me directly should you have any questions.

Sincerely,

Karluss Thomas

SEHSC Executive Director

cc: Heather Njo (EPA) 

 

6

For example, in TSCA section 4 test rules, the regulatory provision describing who is required to test may provide a carve-out indicating 

that all manufacturers and processors of the chemicals substance “other than as an impurity” are subject. See, e.g., 40 C.F.R. 799.5055. 

There would be no need for such a carve-out if the term process or processor did not encompass such activities. 

7 We note that the direct discharge sites that will be sampled per Appendix 1 to the ECA include D4 processors and formulators. And, results 

for those sites will also address processing with D4.