WATERVILLE – Army Spc. Wade A. Slack was killed Thursday in Jaghatu, Afghanistan, by “indirect fire” from a rocket or mortar fired by insurgents, the Department of Defense said in a news release this weekend.

Slack, 21, of Waterville, was assigned to the 707th Ordnance Company (Explosive Ordnance Disposal), 3rd Ordnance Battalion, Joint Base Lewis-McChord, Wash.

He worked in combat, performing duties depicted in this year’s Academy Award-winning film for best picture, “The Hurt Locker,” but did not lose his life in an accidental detonation while working to disarm a bomb, Joseph Piek, a retired soldier who works as a civilian for the Lewis-McChord public affairs office, said by telephone Saturday. In the film, explosive-ordnance disposal technicians wearing 80-pound suits tackle the nerve-racking work of disarming unexploded bombs.

Piek said the military uses the word “insurgent” as a generic term for enemy forces in Iraq and Afghanistan.

Slack was the son of Alan and Rose Slack of Waterville and Mary Slack of Waterville, and a 2007 Waterville High School graduate.

Alan Slack, veterinarian at the New England Animal Hospital in Waterville, said Friday that his son “had been oriented for military service since 14” and that he enlisted while a senior in high school for specialized training that required “intelligence and a top-secret security background check.”

“It’s not something every person can qualify for,” Slack said. “He had been in Afghanistan the last 10 months.”

Slack said his son was killed soon after his unit had completed the disposal of an improvised explosive device and was waiting to be airlifted back to its base.

According to unit records, Slack enlisted Sept. 1, 2006, in Portland. He reported to Fort Leonard Wood, Mo., for basic training on July 11, 2007; then completed training in his military occupational specialty at Redstone Arsenal, Ala., and Eglin Air Force Base, Fla.

On Sept. 16, 2008, he reported to then-Fort Lewis, Wash., where he was assigned to the 707th Ordnance Company (Explosive Ordnance Disposal), 3rd Ordnance Battalion (EOD), according to a news release from Joint Base Lewis-McChord.

He was deployed to Afghanistan in support of Operation Enduring Freedom. It was his first deployment.

Slack’s awards and decorations include the National Defense Service Medal, the Global War on Terrorism Service Medal, the Army Service Ribbon and the Explosive Ordnance Disposal Badge.

Gov. John Baldacci on Friday ordered flags lowered to half-staff on the day of Slack’s funeral, the date of which had not been set.