Reporting from Washington — Greg Nielson pushed a joystick, and a video camera zoomed in on three men in moon suits and gas masks as they prepared to blow up a weapon of mass destruction less than five miles from the White House.
Later, the crew slid the rusting World War I artillery shell into a small steel vault and sealed the door. They detonated a shaped explosive charge to cut the projectile open, and pumped in reagent to neutralize its contents: liquid mustard, an infamous chemical warfare agent.
The process is "as safe as sliced bread," said Nielson, the operation leader, at a control panel in a nearby trailer. "Maybe safer."
The destruction of five poison-filled shells and 20 other suspect items ended last week. But the strange saga of America's most unusual hazardous waste site is far from over.
Since 1993, the Army Corps of Engineers has removed 84 chemical-filled shells and more than 1,000 conventional munitions, plus at least 44,000 tons of contaminated dirt and debris, from the verdant campus of American University and the manicured lawns of Spring Valley, one of Washington's most prestigious neighborhoods.
The toxic trash dates from 1917 and 1918, when the military leased the then-rural campus and nearby farms to test gruesome gases. After the war, soldiers and scientists buried lethal leftovers in unmarked pits, calling the area Death Valley.
A developer renamed it Spring Valley, and mansions sprouted. Presidents Lyndon B. Johnson, Richard Nixon and George H.W. Bush lived here before they entered the White House. U.S. Atty. Gen. Eric H. Holder Jr. and Sen. Dianne Feinstein (D-Calif.), among other top officials and foreign diplomats, reside here now.
The Pentagon says 5,000 old arsenals and other former defense sites may hold hazardous waste. But the bomb hunt here "is the No. 1 priority," said Col. David Anderson, the Army Corps district commander. "This is the nation's capital."
The Army has spent $180 million and expects to spend $15 million more to finish the job, Anderson said.
So far, government agencies and independent studies have not found adverse health effects on American University students or the 4,000 or so residents of Spring Valley.
"Overall, community health is very good," said Beth Resnick, coauthor of a 2007 study by the Johns Hopkins Bloomberg School of Public Health. "Cancer rates overall are low. Mortality rates are low."
She said a new study may focus on several people who lived near the burial pits and reportedly suffered rare cancers, blood disorders and other ailments. It's not known if military waste played a role.
For now at least, the oak-shaded streets buzz with lawn mowers, not public outcry. Property values are stable, and activists acknowledge that few residents share their suspicion that the Army Corps has downplayed dangers and concealed data, a charge the Army denies.
"They're deliberately misleading people," said Nan Wells, who represents part of Spring Valley in local government. "They just want to leave."
Tom Smith, another Army Corps critic, said many residents have become complacent. "We've grown a little too accustomed to having the Army in our backyards, literally in our backyards, for the last 17 years," he said.
The yard that causes the most concern is between the official residence of South Korea's ambassador, Han Duk-soo, and the white-columned house of American University's president, Cornelius Kerwin. Previous digs unearthed more than 300 munitions and chemical weapons debris on the South Korean property and toxic chemicals beside the AU house.
A high fence with barbed wire guards the current excavation, known as Pit 3. A two-story, tent-like structure covers the hole to prevent leaks. It also hides the men in hazmat suits and breathing apparatus on a winding street of stately homes and purple azaleas.
Engineers believed the digging was almost finished until they uncovered more than 500 pounds of jugs, beakers and other laboratory glassware this spring. On March 29, a broken bottle spewed smoke inside the containment tent.
Tests show the fumes came from arsenic trichloride, which is poisonous by inhalation, skin contact or ingestion. Known as "arsenic butter," the compound was used to boost the lethality of mustard, a blister agent that reportedly caused more than 1 million casualties in World War I, and to produce lewisite, dubbed the "dew of death," and other chemical warfare agents.
The find was deemed so perilous that work has been halted until Army engineers can determine how to safely proceed.
"The concern is they may find a lot more, and there's a real question whether the air pollution controls are adequate," said Paul Chrostowski, an environmental scientist who monitors the cleanup for the university.
Kerwin, the university president, was forced to abandon his home for two years when his yard was dug up. He and his wife moved back last fall after tests showed the hazard was gone.