Dow Corning INTERNAL 

Via Electronic Mail and Certified Mail 

March 1, 2012 

Maria J. Doa, Ph.D. 

Director 

Chemical Control Division 

Office of Pollution Prevention and Toxics 

U.S. Environmental Protection Agency 

1200 Pennsylvania Ave., NW 

Washington, DC 20460 

Re: Proposed Terms of Environmental Monitoring Proposal for Certain Cyclic Siloxanes 

Dear Dr. Doa: 

On behalf of the member companies1

 of the Silicones Environmental, Health and Safety Council of 

North America (SEHSC)2

, this letter follows on our January 31, 2012 submission to the U.S. 

Environmental Protection Agency (EPA) and our recent communications regarding the development of 

an environmental monitoring proposal for certain cyclic siloxanes. In Attachment 1 to this letter, we are 

providing proposed terms of an Enforceable Consent Agreement (ECA) for an Environmental 

Monitoring Program for Octamethylcyclotetrasiloxane (D4) and Decamethylcyclopentasiloxane (D5). 

The purpose of the proposed Environmental Monitoring Program is to provide additional information on 

the presence and concentration of D4 and D5 in the environment and on sources of and pathways to the 

environmental concentrations of D4 and D5. The proposed Environmental Monitoring Program is based 

on generic Conceptual Site Models (CSMs) developed for D4 and D5 manufacturing, processing and 

formulating (MPF) facilities and municipal wastewater treatment plants (WWTPs), existing monitoring 

data and available science on the environmental properties of D4 and D5, feedback we have received to 

date from EPA, and consultation with an environmental consulting firm. The proposed Environmental 

Monitoring Program would augment the existing international environmental monitoring program for D4

and D5 being conducted by the global silicones industry under a voluntary product stewardship initiative 

(VPSI).3

 

Under the proposed Environmental Monitoring Program, monitoring will be conducted at four locations 

that correspond to D4/D5 MPF sites owned/operated by SEHSC member companies that are direct 

 

1

 Bluestar Silicones USA Corporation; Dow Corning Corporation; Evonik Goldschmidt Corporation; Milliken & 

Company*; Momentive Performance Materials Inc.; Shin-Etsu Silicones of America, Inc.; and Wacker Chemical 

Corporation. *Milliken & Company recently acquired SEHSC member company, SiVance, LLC. 2

 SEHSC is a not-for-profit trade association comprised of North American silicone chemical producers and 

importers. For more than 30 years, SEHSC has promoted the safe use of silicones through product stewardship 

and environmental, health and safety research. A primary focus of SEHSC is to coordinate scientific research on 

health, safety and environmental issues involving silicones. 3

 Additional information on environmental monitoring being conducted under the VPSI is provided in Attachment 

2. 
 

dischargers of process wastewater. At each of the designated locations, there will be two sampling 

events involving the collection and analysis for D4 and D5 in effluent at the MPF’s site’s outfall and in 

sediment, surface water, and biota (benthic and fish species) in the receiving waters. 

Environmental monitoring will also be conducted at five locations that correspond to Municipal WWTPs 

meeting certain specified criteria. At each of those locations, there will be two sampling events 

involving the collection and analysis for D4 and D5 of the following: WWTP influent, effluent, and 

biosolids; and surface water, sediment, and biota in the receiving waters. At one of the sites, air 

monitoring will be conducted. 

We are looking forward to the March 7, 2012 meeting we have scheduled with EPA to review and 

discuss the specific elements of and rationale for the proposed Environmental Monitoring Program. In 

the meantime, if you have any questions regarding this submission, please do not hesitate to contact 

me. 

Sincerely, 

Karluss Thomas 

Executive Director 

Enclosures 

Attachment 1 – Proposed Terms of Enforceable Consent Agreement for D4/D5 Environmental 

Monitoring Program 

Attachment 2 – Global Silicones Industry International Voluntary Product Stewardship Initiative