Risk Evaluation for Octamethylcyclotetra- siloxane (D4)
EPA granted the manufacturer request for risk evaluation for octamethylcyclotetra- siloxane (D4) in October 2020, and this chemical is currently undergoing risk evaluation.
Learn more about manufacturer-requested risk evaluations.
Find other information about other chemicals undergoing risk evaluations under TSCA.
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Background on D4
D4 is a common chemical name for octamethylcyclotetra- siloxane. The primary use for D4 is to make other silicone chemicals and as an ingredient in some personal care products. Information from the 2016 Chemical Data Reporting (CDR) for D4 indicates the reported production volume is between 750 million and 1 billion pounds per year (domestic manufacture including import). D4 was identified in the 2014 Update to the TSCA Work Plan. Additionally, in 2014 EPA issued an enforceable consent agreement for D4 requiring environmental testing data to help the agency better understand the amount of D4 released into the environment and the quantity of D4 in water, sediment and aquatic organisms.
Uses of D4
In the draft scope of the D4 risk evaluation, EPA preliminarily identified conditions of use associated with the manufacture and importing; processing; distribution in commerce; industrial, commercial and consumer uses; and disposal of D4, including:
- In the production of other silicone chemicals;
- In paints and coatings;
- In cleaning, laundry, and dishwashing products; and
- In other commercial and consumer products, including adhesives and sealants, automotive care products, and other plastic and rubber products.
The above listed conditions of use are ways that a person or the environment could be potentially exposed to this chemical. However, when conducting a risk evaluation, EPA also considers the hazards (i.e., health effects or environmental impacts) that could occur from coming in contact with a chemical.
Recent Activities and Opportunities for Public Comment
In March 2022, EPA published the final scope document outlining the hazards, exposures, conditions of use, and the potentially exposed or susceptible subpopulations that EPA expects to consider in its risk evaluation. EPA published and took public comment on the draft scope document in September 2021.
- Read the final scope of the risk evaluation for D4 and EPA’s response to comments on the draft scope.
- Read the supporting and decision documents for this manufacturer requested risk evaluation.
As EPA continues to move through the risk evaluation process there will be additional opportunities for public comment, including a public comment period on the draft risk evaluation. In addition to public comment periods, EPA will continue to engage with stakeholders as it develops the risk evaluation. Stakeholders should reach out to EPA via the staff contact to engage with the agency.