More workers at Hanford have reported suspicious odors and symptoms consistent with possible exposure to chemical vapors in recent days.
Areas near, but outside, tank farms were cleared both the evening of June 15 and Thursday morning to check for chemical vapors.
The incidents came days after contractor Washington River Protection Solutions announced that it and union leaders had agreed to a very limited loosening of some vapor-protection requirements, with possibly more to come later in the summer.
On Thursday three workers reported suspicious odors outside the AW Farm. Because they were not within the fence line of a tank farm they were not required to wear supplied air respirators for protection against chemical vapors associated with waste in underground tanks.
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On the Friday evening before that two workers were in the pump storage room of the 242-A Evaporator when odors were detected as preparations were being made for an upcoming effort to evaporate liquids from tank waste. The evaporator building is outside any tank farm.
In the two incidents, four workers were medically evaluated and a fifth worker declined to be checked. Two of the workers reported symptoms.
Although medical privacy restricts the release of information about symptoms, they can include coughing, shortness of breath, headaches and a metallic taste in the mouth.
All four were released to return to work and areas were reopened after industrial hygiene technicians checked for chemicals.
The incident was not expected to delay the start of an evaporation campaign this weekend that is expected to continue for a couple of weeks. The work will free-up space in double-shell tanks to hold more waste from leak-prone single-shell tanks.
Suspicious odors also were reported earlier this year on two successive days in February, with all workers involved declining medical checks. They were outside tank farm boundaries where supplied air respirators are not required.
On June 12, the Hanford tank farm contractor announced that some limited work in the AP Tank Farm may be done using full-face air-purifying respirators rather than the more cumbersome supplied air respirators, that usually require workers to carry an oxygen tank on their backs.
The air-purifying respirators will be allowed only for limited activities, such as equipment calibration and preventive maintenance when no waste is being disturbed, which can increase the risk of vapors being released. Workers still may use supplied air respirators, if they choose.
The AP Tank Farm has a recently upgraded ventilation system, while some other tank farms with older tanks vent directly into the atmosphere.
The air-purifying respirators had been allowed for part of last year in the AP Tank Farm, but then a third-party expert selected by the Hanford Atomic Metal Trades Council asked for more data on certain chemicals.
It has since concurred that limited use of air-purifying respirators is safe.
Later in the summer, air-purifying respirators could be allowed for limited work at some other tank farms with active ventilation systems, according to Washington River Protection Solutions.
The state of Washington, Hanford Challenge and union Local 598 filed a lawsuit in federal court in September 2015, seeking better protection for Hanford workers at risk of inhaling chemical vapors.
The state has argued that workers have been sickened for decades by vapors, and Hanford Challenge has said that some workers have developed serious respiratory and neurological illnesses from chemical exposure.
The trial in the case has been repeatedly delayed since around the start of 2017 as plaintiffs and the defendants — the Department of Energy and Washington River Protection Solutions — try to reach a settlement agreement.
Earlier this month U.S. Judge Thomas Rice reset the trial for the 11th time at the request of plaintiffs and defendants to allow another 60 days of negotiations.
The trial now has been moved from April 8, 2019, to June 24, 2019. Deadlines to prepare for trial also were extended, with the first one set for Aug. 7, when plaintiffs must identify the experts they plan to use at trial.