Spokane, Washington: Washington plans to sue the US Department of Energy and its contractor to protect workers from hazardous vapours at the Hanford Nuclear Reservation, the nation’s most polluted nuclear site, state Attorney General Bob Ferguson said Wednesday.

A report last month found the Energy Department does not have an adequate system to detect whether harmful vapours are sickening workers.

More than 40 workers in the past year have reported smelling vapours and then becoming ill after working around some of Hanford’s 177 underground storage tanks holding nuclear waste. The workers were checked by doctors and cleared to return to work.

The nuclear reservation near Richland contains waste left over from the Cold War-era production of plutonium for nuclear weapons.

Ferguson said on Wednesday that Hanford workers since 1987 have been reporting exposure to harmful vapours, with no solution found.

“Hanford workers face a very real and immediate health risk,” Ferguson said. “The federal government has a responsibility to keep these Washington workers safe, and I intend to hold them accountable.”

Under federal law, a lawsuit can be filed 90 days after the intent to sue is issued, Ferguson said. “There is a 90-day clock starting now,” he said at a news conference in Seattle.

The Department of Energy in a prepared statement said it had received the notice and declined to comment on the merits of the threat to sue. “The Department of Energy is committed to protecting workers, members of the public, and the environment,” the agency said.

Meanwhile, Washington River Protection Solutions said it initiated the latest report of the vapour problems that was released last month. The contractor said it “remains committed to protecting its workforce.”

“WRPS believes that implementing the ... report’s recommendations will further reduce worker exposure to chemical vapours,” the contractor said in a statement.

Ferguson said the intent of his action is to produce a legally enforceable agreement or court order to protect workers from the vapours. If there are productive talks with the other parties, his office may not file a lawsuit, he said.

During the past couple of decades, tanks workers have reported “nosebleeds, headaches, watery eyes, burning skin, contact dermatitis, increased heart rate, difficulty breathing, coughing, sore throats, expectorating, dizziness and nausea,” Ferguson said. “Several of these workers have long-term disabilities.”

The report issued last month concluded that the methods used to study the vapour releases were inadequate, and the methods did not account for short but intense releases of vapours from the tanks. The report was prepared by a team of experts led by the Department of Energy’s Savannah River National Laboratory.

The team was formed in June at the request of Washington River Protection Solutions to study the vapour releases. Its report contained 10 overarching recommendations and more than 40 supporting recommendations. They include proactively sampling the air inside tanks to determine its chemical make-up” accelerating new practices to prevent worker exposures” and modifying medical evaluations to reflect how workers are exposed to vapours.

Hanford for decades made plutonium for nuclear weapons, including the bomb dropped on Nagasaki, Japan. About 56 million gallons of the most highly radioactive and toxic wastes are stored in the underground tanks. Clean-up of the site costs more than $2 billion (Dh7.3 billion) per year, and the work is expected to take decades.

The Department of Energy has said monitors worn by tank workers have found no samples with chemicals close to the federal limit for occupational exposure.