Army begins fourth D.C. dig for munitions

By Brett Zongker - The Associated Press
Posted : Thursday Nov 1, 2007 21:22:16 EDT

WASHINGTON -- The Army Corps of Engineers is beginning a major dig for World War I chemical munitions near American University, including artillery that might contain toxic agents such as mustard gas, engineers said Thursday.

It's the fourth excavation on or near the campus in the affluent Spring Valley neighborhood in Northwest Washington in nearly 15 years, ever since the discovery of disposal pits from the Army’s former chemical warfare station at the university.

The station was used for developing and testing weapons.

The latest site, a home between the South Korean Ambassador's residence and the former university president’s home, is the "last known burial pit," said Dan Noble, project manager for the Army Corps' Spring Valley cleanup.

A metal containment structure was built over the pit with blast-resistant walls, along with a decontamination tent in the front yard of the house, which is now owned by the university. Workers are wearing hazardous materials suits and breathing systems while they dig -- first with a mechanical shovel and then slowly by hand when they reach the munitions. Air within the structure will be monitored continuously, Noble said.

"There's a possibility the soil may have become contaminated," he said. "If we do get a chemical release in the pit, we’ll know immediately."

A tan fabric "vapor containment cover" over the structure is designed to prevent the release of any toxic fumes, and air filters in the back yard are designed to capture any chemical vapors.

Work officially began Monday, but no munitions had been located by Thursday, project engineers said. The $8 million excavation is scheduled to last 14 weeks.

In case of an accident, sirens and a reverse 911 call system will notify the university and residents at 49 homes to shelter in place, Noble said.

"With all the experts we have on site, we think the chance that there would be an event that would affect the surrounding community is very, very remote," he said.

American University President Neil Kerwin notified the campus of the dig in a Sept. 27 memo. He wrote that tests show the possible presence of chemical munitions, including mustard gas and arsine, a flammable gas that's considered more volatile. Kerwin called a chemical release "highly unlikely," but the university asked the Army to use real-time air monitoring and an extra layer of aluminum sheeting around the containment unit as an extra precaution.

Kerwin has chosen not to move into the university president's home next door to the munitions pit. The site is behind two academic buildings and the university’s field hockey turf.

"We've been able to work around a lot of the athletic issues," said Maralee Csellar, a spokeswoman for the 10,000-student school. "On a day-to-day basis, your general student isn't going to be affected ... Still, we wanted to make sure they are aware."

No student housing falls within the Army Corps' safety zone around the dig, she said.

The area behind the campus was mostly farmland during World War I, but developers later unknowingly built multimillion-dollar homes over munitions pits. A contractor at one home found unexploded mortar and artillery shells in 1993, leading to an evacuation and subsequent excavations.

A small fire broke out in the containment unit during a 1999 excavation at the South Korean ambassador's residence. Officials at the time said the fire was ignited when a chemical agent called white phosphorus made contact with the air. Several homes were evacuated.

The latest dig, to at least 8 feet below the surface, will remove soil and any munitions in protective containers to be transported by police escort to a nearby federal holding facility, Noble said. But officials aren’t exactly sure what they will find or how much more digging they may have to do beyond their initial plan.

"We simply don’t know at this time if there are munitions going toward the house or going under the house," said Ed Hughes, program manager for the Spring Valley cleanup. "We have trained explosive ordinance technicians working in this pit ... They're extremely careful."