Biological Effects of Short, High-Level Exposure to Gases: Ammonia

This report presents an analysis and synthesis of the available literature concerned with possible health and performance effects of exposures to ammonia. The US Armys concern is with short, high-level exposures that may exceed present threshold limit values of the American Conference of Governmental Industrial Hygienists 25 ppm or 17 mgcum as a TWA and a ceiling of 35 ppm or 24 mgcum for 15 minutes. The organs primarily affected by exposure to ammonia gas are the respiratory tract and the eyes. During brief exposures to concentrations of 500 ppm 348 mgcum or less, the biologic responses are immediate, reversible, and mainly irritant. Below 50 ppm 35 mgcum, there are no significant effects except that the odor of ammonia is detectable. Between 50-100 ppm 35-70 mgcum, most people experience some degree of irritation of the eyes, nose and throat. There is some evidence indicating that personnel may become acclimated to the irritant effects after only 1 or 2 weeks of intermittent exposure at these levels. Around 130 ppm 90 mgcum, approximately half of exposed personnel experience lacrimation. Lacrimation has been reported in subjects inhaling 500 ppm 348 mgcum of ammonia via face mask, which should have prevented direct contact of ammonia with the eyes.