Collapsed tunnel may have gone unnoticed

Associated Press

SPOKANE, Wash.

The large sinkhole that caved in a tunnel filled with radioactive waste at a sprawling Washington state nuclear-waste repository may have gone unnoticed for days before its discovery because workers do not patrol tunnel sites daily, a spokesman for the U.S. Department of Energy said Thursday.

The sinkhole was found Tuesday, prompting an emergency at the Hanford Nuclear Reservation with evacuations of some workers and orders for others to stay inside buildings scattered across the 500-square-mile safekeeping location for radioactive waste dating from World War II.

Authorities plan to investigate why and when the roof of the tunnel suffered a partial cave-in, creating the sinkhole that poured dirt into the tunnel containing railroad cars with nuclear waste, the agency said.

The cave-in could have happened as many as four days before its discovery Tuesday, said energy department spokesman Mark Heeter.

No one was hurt, and no radiation escaped into the environment before the sinkhole was filled in with 54 truckloads of soil late Wednesday night, the Energy Department said.

The 8 feet of dirt that fell into the tunnel after its roof partially collapsed may have prevented radiation from escaping into the environment, Heeter said.

But Washington state officials were taken aback upon learning after the collapse that tunnel inspections were made on what they called an infrequent basis.

The 360-foot long rail tunnel was built in 1956.