The likelihood of auto-ignition occurring while hydrolyzing particulate aluminum phosphide with H.sub.2 O to produce phosphine is reduced by conducting the hydrolysis of the aluminum phosphide in the presence of both a source of ammonia or ammonium ions and zinc or zinc compound, the latter reducing the temperature rise associated with the hydrolysis.
This is a continuation-in-part of Application Ser. No. 436,769, now U.S. Pat. No. 4,503,032, filed Oct. 26, 1982 as a continuation of Application Ser. No. 215,586, filed Dec. 11, 1980, now abandoned.
