More workers sought medical evaluations Friday because of potential exposure to chemical vapors at Hanford a day earlier, bringing the total to 20 people.
Thirteen reported having various symptoms, most of which were not made public, and seven sought medical evaluations as a precaution, according to Washington River Protection Solutions.
All but one had been cleared to return to work Friday afternoon. The remaining worker was still being evaluated, according to Washington River Protection Solutions, the Department of Energy’s tank farm contractor.
Work to empty waste from Tank AY-102, Hanford’s double-shell tank with an interior leak was stopped Thursday afternoon after suspicious odors were reported.
Friday, Washington River Protection Solutions said work to empty waste from the tank is not expected to resume for about three months, the time that will be needed to switch out to technology that is expected to be more effective in retrieving waste.
During the day shift Thursday a dozen workers went to the on-site medical provider for evaluation. Some reported smelling a suspicious odor or developed symptoms, such as headaches.
That evening two more people reported having symptoms after they had gone home from work. Because the on-site medical provider was closed, they went to Kadlec Regional Medical Center in Richland as is Hanford policy.
The only pumping planned at Tank AY-102 for several months is to empty leaking waste between its shells back into the primary shell, as needed.
Friday six more workers reported symptoms they believed were related to their work Thursday in the tank farms and were given on-site medical evaluations.
Symptoms typically reported include coughing, headaches, nose bleeds, watery eyes and sore throats. But workers are concerned that they could develop serious illnesses long term from the chemical exposure.
Waste was being transferred Thursday from Tank AY-102, which is being emptied because of a leak into the area between its shells, to a sturdier double-shell tank in the AP Tank Farm.
The suspicious odors were reported in areas near where the waste transfer line ran, including at a nearby single-shell tank farm where construction work was being done.
Washington River Protection Solutions reported that industrial hygiene monitoring found only chemical concentrations that were well below regulatory limits.
The chemical vapors are associated with the waste in Hanford’s underground storage tanks, which hold a mix of radioactive and hazardous chemical waste from the past production of plutonium for the nation’s nuclear weapons program.
Although Hanford officials do not plan to pump more waste from Tank AY-102, Hanford’s oldest double-shell tank, until summer, waste that is leaking into the space between the tank’s shells will be pumped out as needed. Pumping can be done to return waste to the tank’s primary shell when it reaches a little more than five inches deep.
The contractor had initially made plans to switch out waste retrieval technologies part way through pumping. With 95 percent of the tank’s estimated 744,000 gallons of waste removed in less than two months, there was a possibility the switch would not be needed.
The Department of Energy and its tank farm contractor are being sued by the state of Washington, seeking better protection of Hanford workers.
However, waste retrieval has slowed as just four inches of sludge remains in the center of the tank, with 20 to 30 inches at its sides. The two sluicers installed in the top of the tank spray liquid waste on the sludge to break it up and move it toward a central pump.
The sluicers will be removed and replaced with four enhanced reach sluicers that can be maneuvered to spray liquid closer to waste in remote parts of the tank.
Getting the new system ready to work is expected to take three months, but DOE has until March 4, 2017, to empty the tank under the terms of a settlement agreement with the state of Washington.
Washington River Protection Solutions also has been working for 15 months to implement a detailed plan to better protect workers from chemical vapors. The plan was developed from recommendations made by an independent panel led by the Savannah River National Laboratory.
The plan is intended, in part, to reduce the high reliance on personal protective equipment and administrative controls, such as ropes strung to keep workers away from potentially hazardous areas. Instead, the plan calls for worker protection to move toward engineered controls and technologies. They include new ventilation systems and new methods to detect and sample chemical vapors.
Now workers are required to wear supplied air respirators if there is believed to be a risk that they could be exposed to chemical vapors, such as when they are near tanks where waste is being disturbed.
Two of the workers evaluated Thursday had left a vapor control zone and had taken off their supplied air respirators when they smelled a suspicious odor and experienced headaches.
DOE and its contractor have both been named in a lawsuit brought by the state of Washington and combined with a lawsuit brought by Hanford Challenge and union Local 598 seeking better protection for workers.