The gear that is protecting Hanford tank farm workers from chemical vapors also is significantly slowing work, according to documents filed in federal court.
A Department of Energy analysis found that the reduction in efficiency ranges from 30 percent to 70 percent, with an average reduction of 50 percent. Tasks that once took a month now take two months.
Because of the change, DOE has proposed it be given an extra year to retrieve waste from the next set of nine tanks in the A and AX tank farms. Retrieval would be completed in fall 2023 under DOE’s proposed schedule to amend the 2010 consent decree, which set court-enforced deadlines for work related to Hanford tank waste.
In late 2014 Washington River Protection Solutions began requiring employees conducting much of the work in the Hanford tank farms to wear supplied air respirators after dozens of workers reported suspected exposure to chemical vapors from waste held in the underground tanks.
The additional safety gear that workers must wear weighs about 40 pounds, including a tank filled with compressed air for breathing that is similar to tanks used for scuba diving, according to court documents filed by DOE. Not only the weight, but also the heat of the extra gear makes workers tire sooner.
Work is interrupted every 20 to 40 minutes so workers can get a new tank of compressed air, and the change can be complicated in radiological areas. The mask used with the respirators disrupts communication among workers and reduces their vision.
More help is needed to support tank farm workers — including to maintain, refill and deliver compressed air tanks, to staff stations that issue masks and to change out tanks in the field.
DOE anticipates that the supplied air respirators will continue to be used for two years through fall 2016 in the A and AX tank farms, where preparations are under way to empty waste in leak-prone single-shell tanks into newer double-shell tanks. The waste, left from the past production of weapons plutonium, is being stored until it can be treated at the vitrification plant to prepare it for disposal.
Washington River Protection Solutions is implementing 47 recommendations made in an independent review that looked at the vapor issue and how workers could be better protected. The goal is to find better ways to protect workers from the vapors than wearing cumbersome supplied air respirators.
More time than the extra year proposed for the A and AX tank farms could be needed if a better way to protect workers is not found by fall 2016, DOE said. Washington River Protection Solutions is looking for engineered controls and technologies to protect workers, such as new ventilation systems and new methods to detect and sample chemical vapors.
Reports of possible vapor exposure have been reduced since workers have been required to wear supplied air respirators for any work in most of the single-shell tank farms and any work that disturbs waste in the double-shell tank farms. The double-shell tank farms have exhausters and most of the single-shell tank farms are passively vented into the atmosphere.
In just over a year through April 2, the number of workers medically evaluated for possible vapor exposures reached 56.
Since April 2 there have been just two incidents, with none of the workers involved working in places or under conditions where they were required to wear supplied air respirators. On April 7 and June 10 a few people reported possible exposure and were taken to the on-site medical provider. All were released to return to work.
The independent review of the tank vapor issue, led by Savannah River National Laboratory in South Carolina, found that short, unpredictable and intense releases of vapors were the possible cause of health effects reported by workers, particularly upper respiratory irritation.
Symptoms have included nosebleeds, headaches, increased heart rate, coughing, sore throats or dizziness. Vapors have been reported for more than 20 years at the Hanford tank farms and some past workers believe their long-term neurological or lung diseases were caused by the exposure.