Richland — Two workers at Hanfords C Tank Farm reported smelling chemical vapors at about 1 p.m. Monday, leading to the evacuation of the seven workers in the tank farm.
The incident happened after work began Sunday night to retrieve waste from single-shell Tank C-102, said Rob Roxburgh, spokesman for Washington River Protection Solutions.
C Tank Farm is the only area at Hanford where waste is being retrieved from Hanfords 149 single-shell tanks. Waste retrieval disturbs the waste, increasing the chances that workers will smell vapors vented into the air.
The two workers were taken to the Hanford occupational medical provider for evaluation and cleared to return to work later in the day, according to Washington River Protection Solutions.
They bring the number of workers evaluated this spring for possible exposure to chemical vapors from Hanford tank waste to 28. Access to C Tank Farm has been restricted until more is known after an investigation planned for this morning and the implementation of any additional protections for workers.
Work was moving quickly on Tank C-102 as retrieval began, which is typical as work begins to empty tanks, Roxburgh said.
The tank contains 319,000 gallons of radioactive and hazardous chemical waste and is not one of the single-shell tanks suspected of having leaked.
Washington River Protection Solutions is using two enhanced-reach sluicing systems in the tank. They were inserted down risers into the underground tank to pump up waste to be sent to a double-shell tank, where it will be stored until it can be treated for disposal.
The systems spray water or liquid waste on the sludge in the tank and move it to a pump for removal. Unlike earlier sluicing systems, the enhanced-reach systems telescope to get nozzles closer to the waste, helping remove more waste.