By Steve Vogel
Washington Post Staff Writer
Tuesday, October 30, 2007
Operating under tight safety restrictions, the U.S. Army Corps of Engineers yesterday began excavating what it calls the "last known burial pit" of World War I chemical munitions in Northwest Washington's Spring Valley neighborhood.
The Army expects to excavate at least fifteen 75mm artillery rounds -- a dozen or more with mustard gas and three with arsine, both toxic chemical agents -- buried in the affluent residential neighborhood that was once a site for developing and testing chemical weapons.
To protect the neighborhood from an accidental release of gases, the Army has erected a large metal containment structure over the pit in the 4800 block of Glenbrook Road, next to an unoccupied home behind American University.
Tan fabric covering the structure is designed to contain and filter chemical vapors, and sirens will warn residents living within a safety zone running 742 feet in every direction from the pit -- the distance based on calculations of the danger from a detonation of a round of arsine, which officials describe as the more "worrisome" of the chemicals because of its volatility.
All residents inside the zone, which includes parts of AU and 49 homes, have been given instructions to stay indoors and not try to leave the area. In a letter to the campus last month, AU President Neil Kerwin called a chemical release "highly unlikely" but said the school would remain "vigilant."
Shortly after 10 a.m. yesterday, an operator inside the containment structure radioed to the project's command post that chemical detection equipment was ready. "We're getting ready to begin digging operations," he radioed.
"Roger -- take everything slow and easy," replied Scott Wunschel, safety officer for the project, who was seated at a computer in a trailer on the campus. A mini-excavator, visible on screens inside the command post, began digging up the soil and loading it into blue barrels.
With that, the latest round of a seemingly unending cleanup operation was underway. The Spring Valley operation dates back to 1993, when the discovery of an artillery round by a construction crew triggered an evacuation and cleanup. More discoveries and excavations followed, as research showed that the Army testing operation during World War I was more extensive than realized.
The presence of the shells sparked concerns about health hazards from chemicals in the ground. Earlier this year, a review by researchers from the Johns Hopkins University School of Public Health found no relationship between cancer cases and chemicals in the ground in Spring Valley but recommended continued environmental tracking.
The canisters buried at the Glenbrook Road site were seen during a previous excavation but could not be recovered because the landowner would not allow further digging. The university now owns the land.
The excavation was supposed to begin in August but was delayed when AU requested additional safety measures, including an extra layer of aluminum sheeting around the containment unit and an air quality monitor between the excavation pit and the AU campus.
"We've got a very robust metal cover to protect against fragmentation," said Army Corps of Engineers Capt. Drew White, the site operations officer.
The project includes a dozen workers in the containment area and 2o to 30 outside the area, including chemical weapons specialists from the Army's Edgewood Chemical Biological Center.
Officials from agencies working with the Corps said the precautions for the excavation are adequate. "All of the public safety measures being implemented are conservative and cover a wide range of protection for human health and the environment," said Steven Hirsh, an official with the U.S. Environmental Protection Agency.
White said the Army is hoping this excavation, expected to last 14 weeks, will be the last major operation in Spring Valley. "We've got more investigating to do but don't believe we have anything more extensive than this to do," he said.
After testing inside the containment are, blue barrels of soil dug up yesterday were taken to a federal holding site near Sibley Hospital in preparation for further study and eventual disposal elsewhere.
The munitions are believed to be about 10 feet deep, and none was recovered yesterday. "Just lots and lots of dirt," White said.