"Smoking" Arsenic Discovery Stops Excavations at Burial Pit 3

Workers found a larger jar with mustard, glassware that was smoking and fuming, scrap munitions and a shell containing a tear gas agent. In late March, the Army Corps uncovered the smoking chemical arsenic trichloride for the first time in the cleanup project. It can be used to develop the blistering agent lewisite, Noble said. Digging was halted shortly after while officials review their safety procedures. American University spokeswoman Camille Lepre said there were no plans to move or cancel any campus events scheduled at the [neighboring] president's house. 
Brett Zongker
Associated Press
April 16, 2010

On Glenbrook Road two houses sit side-by-side. To the left is the stately, stone home with eight white columns and fine landscaping where American University President Cornelius Kerwin hosts picnics with students; right next door is a brick house surrounded by a 10-foot chain link fence, topped by a single strand of barbed wire. Two structures encased in plastic tarps sit atop the most potentially lethal toxic waste site in any U.S. city ... Behind Sibley Hospital, the Army is disposing bombs in the EDS, a mobile unit that's designed to take the toxicity from the chemicals. The EDS is right next to Dalecarlia Reservoir, 50 yards away from a water treatment facility, and not far from an assisted living facility.
Harry Jaffe
Washington Examiner
April 18, 2010

Fuming bottle of Arsenic trichloride found at 

Pit 3 on Glenbrook Road (USACE Ppt, pg. 23)