A collapse of earth above a nuclear waste storage tunnel that prompted an emergency declaration in Washington state is now larger than previously estimated, state and federal officials said Tuesday.

The now measures about 400 square feet (37.1 square meters) instead of the 16 square feet (1.4 square meters) first reported at the Hanford Nuclear Reservation, according to the U.S. Department of Energy.

The tunnel is next to the Plutonium Uranium Extraction Facility, also known as PUREX. The Hanford site is regularly updating the situation.

Randy Bradbury, a spokesman for the Washington state Department of Ecology, said officials detected no release of radiation and no workers were injured.

No workers inside the tunnel when it collapsed Tuesday morning, but nearby workers were evacuated and others who were farther away were told to remain indoors, Bradbury said.

Officials detected no release of radiation and say there were no workers inside the tunnel. Nearby workers were evacuated.

The agency says the rail tunnels are hundreds of feet long, with about 8 feet of soil covering them.

The incident caused the soil above the tunnel to sink between 2 feet and 4 feet.

Hanford in Benton County, Wash., along the Columbia River for decades made plutonium for nuclear weapons and is now the largest depository of radioactive defense waste that must be cleaned.

The sprawling Hanford site, founded in early 1943, is about half the size of Rhode Island.