A method for studying the reaction of phosphine with metals has been developed, using a technique based on depletion of the gas from an enclosed atmosphere. The rate of the reaction phosphine with copper exceeded that of all other metals by one order of magnitude or more. Corrosion was found to be increased with higher relative humidities, fumigant concentrations, oxygen levels and with repeated treatments with the phosphine. The liquids that accumulated on the surfaces of copper, silver and gold during the course of the reaction were collected and found to be manly acids of phosphorus. In a search for inhibitors of the reaction, potassium dichromate was found to give a high degree of protection; sodium carbonate and a commercial lacquer made for automobile ignition systems reduced the rates of the reaction to a lesser degree.