40 CFR §180.1159

1. (a)An exemption from the requirement of a tolerance is established for residues of pelargonic acid in or on all food commodities when used as a plant regulator on plants, seeds, or cuttings and on all food commodities after harvest in accordance with good agricultural practices.
2. (b)Pelargonic acid when used as an herbicide is exempt from the requirement of a tolerance on all plant food commodities provided that:
   1. (1)Applications are not made directly to the food commodity except when used as a harvest aid or desiccant to: any root and tuber vegetable, bulb vegetable or cotton.
   2. (2)When pelargonic acid is used as a harvest aid or desiccant, applications must be made no later than 24 hours prior to harvest.
3. (c)An exemption from the requirement of a tolerance is established for residues of pelargonic (nonanoic) acid in or on all raw agricultural commodities and in processed commodities, when such residues result from the use of pelargonic (nonanoic) acid as an antimicrobial treatment for application on food contact surfaces such as equipment, pipelines, tanks, vats, fillers, evaporators, pasteurizers and aseptic equipment in restaurants, food service operations, dairies, breweries, wineries, beverage and food processing plants.