This regulation establishes an exemption from the requirement of a tolerance for residues of silica, amorphous, fumed (crystalline free) (CAS Reg. No. 112945-52-5) also known as silicon dioxide fumed amorphous when used as an inert ingredient when applied to animals. Cabot Corporation submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act (FQPA) of 1996, requesting an exemption from the requirement of a tolerance. This regulation eliminates the need to establish a maximum permissible level for residues of silica, amorphous, fumed (crystalline free). By law, EPA is required to reassess 66% or about 6,400 of the tolerances in existence on August 2, 1996, by August 2002. Upon publication of this final rule, one tolerance reassesment for the existing tolerance exemption in 40 CFR 180.1001(c) for silicon dioxide fumed amorphous will be counted toward the August 2002 review deadline of FFDCA section 408(q), as amended by FQPA in 1996.