Work to empty waste from Hanford Tank C-102 resumed during the weekend after a halt caused by chemical vapors in late April.
Two workers reported smelling vapors April 28, bringing the number of workers receiving medical evaluations for possible vapor exposure to 28. All have been cleared to return to work, according to Washington River Protection Solutions.
Workers in the C Tank Farm now are required to wear at least half-face respirators that use a filter cartridge when tank pumping is under way or when doing tasks that could expose them to vapors. They may choose to wear full-face respirators that also cover their eyes.
The fence around the tank farm has been posted to indicate the chance of vapors being present at a very low level. In addition, the vent stack flow rate has been increased to help push any tank emissions above the work area to disperse.
The vapors were smelled in April shortly after work started to empty Tank C-102.