Karluss Thomas Senior Direc tor UNITED STATES ENVIRONMENTAL PROTECTION AGEN C Y WASH IN GTO N , D.C. 20460



### MAY 1

### 3 2015

S ili cones Env ironmental, Health , and Safety Center Americ an Chemistry Council 700 2nd St re et NE Washington, DC 20002 OFFICE OF CHEM I CAL SAFETY AND POLLUTION PREVENTION

Re: Enforceable Consent Agreement for Octamethylcyclotetrasiloxane (D4) (CASRN: 556- 67

- 2) Dear Mr. T homas : This le tter follows the April 30, 20 15 , conference call between the U.S. Environmental Protection Agency, th e S ili cones Environmental, Health and Safety Center (SEHSC), and Russell Mait of the Evonik Corpo ration regarding the indirect discharge sur vey re sults used to identify potential wastewater treatment plant (WWTP) sites to fulfi ll the enfo rceab le consent agreement (ECA) referenced in the subjec t line above. Following the call, EPA reviewed th e comp leted su rve ys and accompanying summary tab le provided by SEHSC. The ECA specifies for the indirect discharge sites th at: All wastewater tre atment sites selected for monitoring must be currently processing was tewater from one or more industrial sites known to be a 04 processor or fo rmulator as documented through in dustri al user surveys or by other readi ly available information
. Section 3 of The Tox i c Subs tan ces Contro l Act specifies that the term " process" means: the preparation of a chemical subs tance or mixture, after its manufacture, for distribution in commerce-( A) in the same form or physical state as, o r i n a d iffere n t form or physical state from, that in which it was received by the person so preparing s u ch substance or mixture, or (B) as part of an article containing the chem i cal substance or mixture. Based on the survey results that SEHSC provided , however, EPA is not able to substantiate that the processing of D4 or the formulat i on of D4-containing products is occurring at many of the i ndustrial sites
. Our rev iew of the survey results appear to indicate that many of the industrial sites are not formulating or p ro cessing D4. Based on the s urvey results submitted, EPA believes that the Gresham
. and Wichita WWTP si tes proposed fo r monitoring may not meet the conditions

lnterne1 Address (URL)· http /lwww epa gov Recycled/Recyclable • Prmted with Vegetable 011 Based Inks on 100% Postconsumer Process Chlorine Free Recycled Paperspecified by the ECA. EP A welcomes the op po rtunity to discuss this fm1h er during the May 20, 2015, conference cal I. SEHSC asserted d uring th e April 30th call that it would provide additional info rm ation that would demonstrate th at the indirect sites selected meet the requirements spec ified in the ECA , including, but not limited to, a:
• Value chain analysis tha t quantifies the D4 co ncentration i n substances typically processed or formulated at the surveyed industrial sites; • Process flow diagram dep icting how D4 gets into the effluent ; and • Rationale fo r the indirect discharge survey and analysis of results demonstrating that th e propo sed wastewater treatment plant loc ati ons meet the D 4 ECA crite ria fo r sele ction of indi rect discharge si te s. Finally , EPA remains concerned that SEHSC has yet to provide the rationale for how the proposed samplin g point of l 00 meters w ill satisfy the d ata requirements of the ECA. The ECA specifies that "each site specific sampling plan wi ll identify whe re the effluent and receiving stream are adeq uately m ixed and the basis for the determin ation." In order to comp ly with th e term s of th e ECA, the agency recommend s that SEHSC : 1. Present available regulatory determination s, mode lin g (as was done for the direct d i scharge locations), and information from visual inspection on mixi ng zones for each site. 2. Based on this information and any other site spec ific factors, pro vide a rationale for the samp lin g p oi nt w h ere the effl ue nt and receivin g s tream are adequately mix e d at each si te. EPA hopes the scheduled conference ca ll with SEHSC on May 20, 2015 , will lead to the eventual resolution of a ll outstan din g issues discussed to date , including SEHSC ' s plan for compl y in g with the ECA with respect to the full number of test s ites. 

### If you h ave any questions , please contact Heather Njo of my staff at 202-564

- 2574 or at njo. heather @ epa.gov.

I Sincerely ,

# ~Mi 

# 0_DJQ,-
Maria J. Doa , Ph .D. Dir ector Chem ica l Contro l Division