BOISE, Idaho (AP) - To test whether U.S. nuclear installations could withstand terrorist truck-bomb attacks, the federal government is planning to detonate two such bombs in the eastern Idaho desert - both made from the same material used in the 1995 Oklahoma City bombing.
"The exact amount of explosives and the magnitude is classified, but we can say it will be no more than the equivalent of 15,000 pounds of TNT," U.S. Department of Energy spokesman Tim Jackson said Wednesday at the Idaho National Laboratory in Idaho Falls. "It's about like a truck bomb."
The Federal Emergency Management Agency estimated the rental truck loaded with ammonium nitrate fertilizer that Timothy McVeigh used to blow up the Alfred P. Murrah Federal Building in Oklahoma City had the equivalent explosive force of 4,000 pounds of TNT.
In a draft environmental assessment the agency released Wednesday, Energy Department officials said the frequency, size and severity of car-bombing attacks against American targets compelled the agency to test whether nuclear site security barriers are vulnerable to explosives delivered by vehicles.
Data collected from the Idaho tests will also be used by other federal agencies, as well as state and local governments, to understand the effects of vehicle bombs on security perimeters of potential terrorist targets.
Besides the Oklahoma City attack, explosive-laden vehicles were used to bomb the World Trade Center in 1993 and the U.S. Air Force Khobar Tower military apartments in Saudi Arabia in 1996.
Officials want to detonate two bombs at the 890-square-mile Idaho nuclear research compound, the first this fall and the second early in 2006.
The first test will focus on the effects of the blast on existing security fixtures used at nuclear installations. Concrete and composite security fences, closed-circuit television cameras and electronic sensors would be placed at various distances from the bomb to see how well they withstand the blast.
The second detonation would test newer protective devices and additional security barriers or vehicles.
Both bombs would be made of an undisclosed amount of ammonium nitrate with as much as 250 pounds of booster material to ensure the explosive detonates properly. The bomb would be placed on a platform resembling a vehicle and the agency estimates each blast would produce a fireball 480 feet high, leave a crater 60 feet wide and be heard as far as 40 miles away.
Since the air blast from the bombs could break glass windows at 4 miles, the proposed site is 11 miles from the closest inhabited building and 12 miles from the nearest town, Mud Lake, a farming community of 270 residents.
"It's possible people in Mud Lake might see a puff of dust that rises from the site," Jackson said.
The draft environmental assessment found that plants of cultural importance to the Shoshone-Bannock Indian Tribe would be destroyed within the 450-foot project zone, animals that use the undeveloped area would have to temporarily change their habitat and archaeological sites might be damaged by road usage.
Tribal members have also told DOE they are concerned the blast will damage lava tube caves in surrounding hills that are used for ceremonial purposes, but a geological assessment conducted by the agency last month determined the impacts would be minimal, since the caves had experienced earthquakes greater than the jolt that would be produced by the explosion.
Energy Department officials said they picked the Idaho site for the blast test after ruling out other potential federal compounds. Sandia National Laboratory in New Mexico is too close to the city of Albuquerque and the soil on much of the Nevada Test Site is contaminated with radioactive fallout left from Cold War-era nuclear bomb testing that could be introduced into the air by the large surface explosion.
Public comments on the draft environmental assessment for the Idaho bomb tests are being accepted by DOE until Sept. 16, 2005.