CFR › Title 21 › Part 582 › §582.166621 CFR §582.1666Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy link(a)Product. Propylene glycol.(b)Conditions of use. This substance is generally recognized as safe (except in cat food) when used in accordance with good manufacturing or feeding practice.