Summary of the Public Health Goal for Cyanide

A Public Health Goal (PHG) of 150 ppb is developed for cyanide in drinking water. The U.S. Environmental Protection Agency’s (U.S.EPA’s) Maximum Contamination Level (MCL) for cyanide in drinking water is 200 ppb. Cyanide, which is also commonly referred to as hydrogen cyanide and hydrocyanic acid, does not appear to be carcinogenic to animals or humans or mutagenic in bacteria. The proposed PHG of 0.15 mg/L (150 ppb) is based on a chronic no-observed-adverse-effect-level (NOAEL) of 10.8 mg/kg-day in rats in which no clinical or histopathological effects were observed.