The contractor hired to clean up underground tanks holding radioactive waste at the Hanford nuclear site halted routine work Thursday after three workers were taken to medical centers following a possible vapor exposure.
Colorado-based CH2M Hill said only essential workers would be allowed into the so-called tank farms — and then only with respiratory protection.
“We are evaluating the situation and will determine the appropriate precautions moving forward,” the company said in a statement.
The three workers were released without restrictions following medical exams, the company said.
The three were working near a pit earlier Thursday when they noticed an odor, described as a “sweet smell,” according to Erik Olds, spokesman for the Energy Department’s Office of River Protection.
They initially declined medical evaluation, but co-workers called 911 when one of them developed a nosebleed, Olds said.
The three workers had been assigned to monitor for radioactivity or chemical vapors during cleanup of the vast site that once made plutonium for nuclear weapons. Several investigations are under way to determine if Hanford workers are being exposed to toxic vapors from the 177 underground tanks, which hold about 53 million gallons of radioactive waste.
Last week, six workers sought medical attention after being exposed to tank vapors in three separate incidents. They later returned to work.
The Energy Department and CH2M Hill have previously said the vapors are not a danger to workers.
For 40 years, the 586-square-mile site in south-central Washington made plutonium for the nation’s nuclear weapons, beginning with the top-secret World War II-era Manhattan Project to build an atomic bomb.
Cleanup costs are expected to total $50 billion to $60 billion, with the work to be finished by 2035.
Six workers at a research site that once made plutonium for the nation’s nuclear arsenal sought medical attention last week after being exposed to chemical vapors wafting from underground tanks of radioactive waste, a watchdog group said Wednesday.
Workers at the Hanford nuclear reservation were exposed in three separate incidents on March 16 and 17 while cleaning up tanks containing waste left over from years of nuclear weapons production, according to the nonprofit Government Accountability Project, based in Seattle.
A U.S. Energy Department official confirmed the six were evaluated and later returned to work.
Tom Carpenter, director of the accountability project’s nuclear oversight campaign, criticized Hanford officials for not equipping the workers with respirators.
“Not only are the vapors toxic and perhaps lethal, the workers have inadequate protection,” Carpenter said. “Hanford put these workers in harm’s way — it borders on criminal negligence.”
The exposures were reported to company managers in a daily meeting and later to employees in a memo.
Rob Barr, director of environmental safety and quality for the U.S. Energy Department’s Office of River Protection, called the exposures a “learning experience” for Colorado-based contractor CH2M Hill, hired to handle tank-waste cleanup at the facility in south-central Washington.
A company vice president said the contractor shares concerns about vapors but insisted scientific evidence showed no threat to workers. “All the technical information I have says we are not endangering anyone,” said Susan Eberlein, CH2M Hill’s vice president of environmental safety, health and quality.
More than 800 workers at Hanford’s sprawling “tank farm” are cleaning up 177 underground tanks holding about 53 million gallons of radioactive waste. Some of the tanks date back to World War II and could contain as many as 1,200 different chemicals.
Contractors have identified the contents of some tanks by sampling, but critics contend no one knows exactly what is in them or what vapors they might give off. Some of the tanks have leaked into ground water.