Cartridge filters performed within an acceptable range in testing of their potential use to protect workers against chemical vapors from radioactive waste at the Hanford Site in Washington state, according to a preliminary evaluation of the trial. However, Stoneturn Consultants, which wrote the preliminary report, said more testing is needed.
Workers now are required to wear supplied air respirators to enter Hanford tank farms under a memorandum of agreement between the Hanford Atomic Metal Trades Council, an umbrella group of 15 Hanford unions, and the Department of Energy facility’s tank farm contractor, Washington River Protection Solutions (WRPS).
HAMTC said it would agree to let its workers use air-purifying cartridges if they are shown to provide protection equal to supplied air respirators based on the opinion of independent experts it selected. WRPS is testing the cartridges with the help of the Pacific Northwest National Laboratory, and HAMTC picked Stoneturn Consultants of Seattle to review the WRPS and national lab study. An independent expert review of chemical vapor issues led by DOE’s Savannah River National Laboratory and released in early 2015 also recommended evaluating whether cartridges can protect against chemical vapors associated with waste in Hanford underground tanks.
WRPS manages the Hanford tank farms that contain 56 million gallons of chemical and radioactive waste, a byproduct of decades of plutonium production at site.
Stoneturns’s preliminary report looked at just two tests done at a single point in time on cartridges for nonpowered air-purifying respirators that operate under negative pressure as a worker inhales to bring purified air through the cartridge. Results could be affected by temperature and humidity, and they cannot be generalized to apply to different weather conditions than at the time of testing, the preliminary report said. The results also might not apply to combinations of chemicals found at different tank farms than those in the AP Tank Farm, where testing was done, the consultant said.
The report recommended expediting the analyses of six more tests that have been conducted. The data should provide a better indication of the cartridges’ performance under a broader range of weather and working conditions, it said. Data also should be collected during waste-disturbing activities, the preliminary report said. The results could differ from analyses of testing done while waste-disturbing work was temporarily halted at Hanford. Additional assessments of injury data and pulmonary function data also are needed.
Stoneturn Consultants discussed the option of powered air-purifying respirators as a complement to nonpowered air-purifying respirators or as an alternative to supplied air respirators. Powered air-purifying respirators offer more protection and might be more comfortable than nonpowered air-purifying respirators. But they have additional challenges, including battery duration and maintenance, the preliminary report said. Stoneturn Consultants also questioned whether preventing inward leakage for the nonpowered air purifying respirators may be as challenging as the cartridge filtering performance that is being assessed now.
