Base officials have recommended that several World War II-era trenches be excavated to determine if they were used for storage of chemical warfare material.
The site currently "poses no health risk," said Robert Wood, chief of the Environmental Restoration Division at Edwards. "But complete excavation is the only way we will ever know the trenches' contents."
The four trenches, 9 feet deep, 15 feet wide and 150 feet long, are near a dormitory complex where 158 airmen live. Base spokesman Maj. Tom Gilroy said Friday that archival records show they may have contained the chemical agents mustard, lewisite, phosgene and chloropicrin.
Edwards, best known for its flight test center, was first used by the government in 1933 as a remote bombing range, and the sparsely populated desert area was used for a variety of military activities during WWII, including chemical weapons training, Gilroy said.
The recommendation to dig up the trenches was endorsed by the Edwards Restoration Advisory Board, composed of military and civilian representatives.
Edwards covers a greater area than the 464 square miles covered by the city of Los Angeles. The base has 197 potentially toxic sites yet to be reviewed for cleanup, Gilroy said, and is on the national priority list for the U.S. Environmental Protection Agency's Superfund cleanup program.
The next step will be the preparation of an engineering evaluation and cost analysis, followed by federal and state environmental review. The excavation, which would not begin for at least a year, would be performed by workers in protective clothing, officials said. They would operate within a temporary structure built over the trenches to prevent any possible contaminants from leaking into the air.
"We wouldn't have considered digging the trenches up if it couldn't be done safely," Wood said.