This regulation establishes an exemption from the requirement of a tolerance for residues of methane sulfonic acid (CAS Reg. No.75- 75-2) when used as an inert ingredient (acidifying agent) in pesticide formulations applied to animals at a maximum concentration not to exceed 3% by weight and when used as an inert ingredient in antimicrobial pesticide formulations applied to food-contact surfaces in public eating places, dairy-processing equipment, and food- processing equipment and utensils at a concentration not to exceed 5,000 parts per million (ppm). Lewis & Harrison, on behalf of BASF Corporation, submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting establishment of an exemption from the requirement of a tolerance. This regulation eliminates the need to establish a maximum permissible level for residues of methane sulfonic acid.