EPA is amending 40 CFR part 180 by promulgating a new tolerance expression for the isomer form of gamma-cyhalothrin. Gamma- cyhalothrin is the isolated active isomer of lambda-cyhalothrin under 40 CFR 180.438. Pytech Chemicals GmbH, 9330 Zionsville Rd., Indianapolis, IN 46268, requested this change in tolerance expression in support of the registration of a pesticide formulation enriched with the gamma isomer of lambda-cyhalothrin.