SALT LAKE CITY (AP) — A wildfire burning on a Utah military installation has officials concerned about the potential it could spread to an area littered with thousands of unexploded shells, which could still detonate.

Utah National Guard spokesman Lt. Col. Hank McIntire said Wednesday the wildfire was moving away from an artillery practice area, but it has previously gotten as close as a few hundred yards. Officials worry about what could happen if it marches back.

"We can't actively fight the fire in that area because of the threat to personal safety," McIntire said.

McIntire said the practice area covers hundreds of acres and has collected shells for nearly a century, since 1914. The unexploded shells could still ignite in a wildfire, sending shrapnel flying.

The Pinyon Fire on Utah National Guard's Camp Williams about 40 miles southwest of Salt Lake City has scorched 4.7 square miles since it was started by lightning on Sunday. It was 40 percent contained Wednesday morning.

People in nearly 100 homes were forced to flee at one point, but evacuation orders were lifted Tuesday. Some residents had left their homes voluntarily.

Unexploded shells are rounds that didn't detonate on impact, possibly because of a manufacturing defect.

The same problem kept firefighters at Camp Williams from actively extinguishing a wildfire two years ago that threated Herriman, a town near the military installation.

Kim Osborn, a fire information officer, said about 270 fire personnel are battling the blaze. McIntire said Black Hawk helicopters are also helping fight the wildfire.

Osborn said the wildfire has destroyed seven training buildings that were part of a mock Afghan village.

The fire is burning on timber, oak, sage and grass.

Osborn said the wildfire fighting efforts were looking good and there were no major concerns.


Associated Press writer Paul Foy contributed to this report.