This regulation establishes an exemption from the requirement of a tolerance for residues of dimethyl sulfoxide (CAS Reg. No. 67-68- 5) when used as an inert ingredient (solvent, co-solvent), in pesticide formulations for pre-harvest applications, including post-emergence use. Exponent, Inc., on behalf of Gaylord Chemical Company submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an amendment to an existing tolerance exemption. This regulation eliminates the need to establish a maximum permissible level for residues of dimethyl sulfoxide for pre-harvest applications.