The former airfield consisted of 1590 acres leased from Sonoma County government, purchased in fee from private owners or obtained by aviation easement. During World War II, it was used to conduct fighter training. Some training involved using of chemical agent identification sets (CAIS). This took place in an area later occupied by the Sonoma County Water Agency Maintenance Yard.

Between October and November 1982, while installing a sewage line, workers were overcome by a white cloud of smoke that appeared in the trench. Several weeks later, construction halted when an ampule of 5percent lewisite solution from a CAIS was found. In August and September 1983, the Technical Escort Unit began excavation of the site and discovered 24 CAIS components. None were hazardous. During the operation, excavations covered an area of 90 feet by 35 feet by 6 feet and over 20,000 cubic feet of earth was removed and sifted. Though further components were found, areas near the excavation are still suspected of containing CAIS components. In 1985, an additional five ampules of gas were discovered and the location was cleaned up under the supervision of the Corps of Engineers with technical assistance from the U.S. Army Toxic and Hazardous Materials Agency.

Chemical Materiel Destruction Agency, and Sonoma County met to discuss the site and potential danger. This site has been visited many times between 1983 and October 1992.

The USACE has completed an Archives Search Report of the Santa Rosa Army Air Field.