RICHLAND, Wash. -- A contractor has identified two possible sources of fumes that have sickened 18 workers during the past two weeks at the nation's most contaminated nuclear weapons site in Washington state.
An investigation at the Hanford Nuclear Reservation found a cut in insulation at a pump, and liquid in unused equipment at tank farms holding radioactive and chemical waste, Washington River Protection Solutions said Thursday.
The cut has been sealed and the old equipment has been cordoned off, the Tri-City Herald reported.
All but one of the workers who reported symptoms have been cleared to return to work. The symptoms include sore throats, headaches, coughing, burning eyes, nose bleeds, a metallic taste, dizziness and accelerated heart rate.
Hanford tanks hold 56 million gallons of waste from nuclear weapons production.
The tanks vent to the atmosphere, with filters preventing radioactive particles from being released. But chemical vapors have been an issue at least since the end of the Cold War, with Hanford officials taking steps through the years to protect workers.
While the investigation to identify other potential sources of vapors is continuing, Hanford Challenge, a Seattle-based watchdog group, says not enough is being done.
On Thursday, it called for Washington River Protection Solutions and the Department of Energy to support workers who have experienced symptoms, to step up monitoring of chemical vapors and to take more protective measures.
Washington River Protection Solutions said it is encouraging workers to wear respirators if they believe it is necessary.
The contractor has kept worker exposure to chemical vapors far below national occupational standards -- generally 10 percent, said spokesman Jerry Holloway.
An Industrial hygiene technical panel with management and employee members who meet regularly to address potential hazards will address the recent chemical vapor issues, Holloway said.