Methyl Silicone Oil: EPA Grants Crucial Exemption for Pesticide Applications

Regulatory Ruling
     WASHINGTON D.C. – In a landmark decision for the agrochemical industry, the United States Environmental Protection Agency (EPA) has issued a final rule establishing an exemption from the requirement of a tolerance for residues of Methyl End-Capped Polydimethylsiloxane (commonly known as Methyl Silicone Oil).
      Published in the Federal Register on March 25, 2026, the ruling confirms that the silicone fluid (CAS Reg. No 63148-62-9) is safe for use as an inert ingredient in pesticide chemical formulations under 40 CFR 180.960.

Implications for the Industry
      This ruling, responding to a petition submitted by Momentive Performance Materials, eliminates the need to establish a maximum permissible level for residues of the substance on food or feed commodities. For formulators, this decision significantly reduces the regulatory burden associated with bringing new pesticides to market.
      “This exemption acknowledges the low toxicity profile of standard methyl silicone fluids,” a regulatory analyst explained. It allows manufacturers to use dimethylpolysiloxane as a defoamer or spreading agent without fearing legal repercussions related to food contamination limits. The ruling is effective immediately, providing a clear regulatory pathway for the use of Methyl Silicone Oil in agricultural adjuvants and crop protection products.