Four more employees of the Waste Isolation Pilot Plant are being tested for possible exposure to radiation.
WIPP is a federally operated nuclear waste disposal site located 26 miles southeast of Carlsbad.
The Department of Energy announced Thursday that the four employees were identified for further testing after WIPP officials adopted more conservative evalation criteria to pinpoint possible exposure to radiation.
Like the 17 employees already determined to have been exposed during the Feb. 14 radiation release, the estimated radiation exposure for the four workers is expected to be below levels that would cause health concerns, according to a DOE news release.
Operations halted at WIPP on Feb. 5 when a salt hauler truck caught on fire underground, forcing immediate evacuations. A separate radiation leak was detected on Feb. 14 and the DOE hopes to send investigation teams underground early next week to determine a cause for the release of americium and plutonium.
Meanwhile, New Mexico's senators want answers about why legally required inspections for WIPP weren't performed by the Mine Safety and Health Administration.
NM senators Tom Udall and Martin Heinrich sent a letter to Labor Secretary Thomas Perez Thursday asking for a written report on why MSHA hadn't performed the legally required inspections at WIPP.
The information about missed safety inspections was revealed in the Department of Energy's accident report on the Feb. 5 fire at WIPP. By law, MSHA is required to inspect WIPP four times a year. The accident report said the inspections had been performed twice in the last three years.
"The health and safety of the workers at WIPP and the surrounding community are our top priorities and it is extremely concerning to learn that a fire in the mining portion of WIPP was a preventable circumstance," Udall and Heinrich wrote in the letter.