Hundreds of workers have been forced to "take cover" after a tunnel in a nuclear finishing plant collapsed in Washington state.

Following the incident Tuesday morning, which a spokesperson told the Independent is still being investigated, a manager sent a message to workers telling them to “secure ventilation in your building” and to “refrain from eating or drinking.” The US Department of Energy activated its Emergency Operations Center Tuesday following the collapse. Some workers were reportedly told to evacuate while others were told to shelter-in-place as officials investigated the severity of the situation.

"The Department of Energy informed us this morning that a tunnel was breached that was used to bury radioactive waste from the production of plutonium at the Hanford Nuclear Reservation," Governor Jay Inslee said in a statement. He said that the White House had reached out to his office as well.

"This is a serious situation, and ensuring the safety of the workers and the community is the top priority," Mr Inslee said. "Our understanding is that the site went into immediate lock down, in which workers were told to seek shelter, and all access to the area has been closed."

A spokesperson for the Hanford site said during a live broadcast that the tunnel collapse was discovered by workers on patrol in the area.

"Crews noticed that a portion of that tunnel had fallen," Destry Henderson, the spokesperson, said, emphasizing that researchers had not found spilled or leaked radioactive materials. "The roof had caved in about a 20 foot section of that tunnel."

The tunnel reportedly contained highly contaminated materials including nuclear waste trains that are used to transport radioactive fuel rods. A spokesperson said that there was no evidence to suggest that radioactive materials had been released and that all of the workers in the area were accounted for. An official tally of those with orders to shelter-in-place was not immediately available, a spokesperson said but there were no reported injuries.

“The U.S. Department of Energy (DOE) Richland Operations Office activated the Hanford Emergency Operations Center at 8:26 a.m,” the Department of Energy said in an earlier statement. “There are concerns about subsidence in the soil covering railroad tunnels near a former chemical processing facility. The tunnels contain contaminated materials.”

The nuclear site, located in the city of Hanford, is a former plutonium production site that was used to help develop the American nuclear arsenal 70 years ago. More recently, however, a private contractor hired by the Department of Energy is working on a $110 billion project to clean up 56 million gallons of chemical and nuclear waste stored in as many as 177 underground tanks there.

Before the Tuesday collapse, those tanks were reportedly leaking toxic and radioactive vapours and chemicals that have been linked to cancer, brain damage, and lung damage. There were at least 61 workers exposed to those deadly vapours last year. Experts have called the location "the most toxic place in America" and "an underground Chernobyl waiting to happen."

Loading....

Cleaning up the Hanford nuclear site has been a priority for the Energy Department for years. The site hasn't produced plutonium since 1980 and a cleanup program was started there in 1989. The area has since been the subject of controversy and has been the target of a lawsuit filed by Washington Attorney General Bob Ferguson last year who contended that the Energy Department and contractor Washington River Protection Solutions had allowed the release of vapours from underground nuclear waste tanks that pose a serious health risk to workers.