40 CFR § 180.101 - Specific tolerances; general provisions.
(a) The tolerances established for pesticide chemicals in this subpart C apply to residues resulting from their application prior to harvest or slaughter, unless otherwise stated. Tolerances are expressed in terms of parts by weight of the pesticide chemical per one million parts by weight of the raw agricultural commodity.
(b) The poisonous and deleterious substances for which tolerances are established by the regulations in this subpart C are named by their common names wherever practicable, otherwise by their chemical names.
(c) The analytical methods to be used for determining whether pesticide residues, including negligible residues, in or on raw agricultural commodities are in compliance with the tolerances established in this part 180 are identified among the methods contained or referenced in the Food and Drug Administration's “Pesticide Analytical Manual” which is available from the Food and Drug Administration, Department of Health, Education, and Welfare, 200 C Street SW., Washington, DC 20204.