Safety procedures are being reviewed after a worker's alarm sounded during preliminary work at the C-400 building.
By Bill Bartleman firstname.lastname@example.org
The work that began earlier this year was stopped Tuesday after a monitoring device worn by a worker sounded an alarm indicating a high level of vaporized TCE, according to Greg Cook, spokesman for Bechtel Jacobs, the firm overseeing cleanup for the U.S. Department of Energy.
It is one of several incidents at the plant in recent weeks involving chemical releases and incidents in areas of the plant where the U.S. Department of Energy stores contaminated equipment and material.
None of the incidents was considered serious or a threat to the public, according to Cook and Elizabeth Stuckle, spokeswoman for USEC Inc., which operates the plant.
An unidentified worker for CDM Federal Services is being tested to determine if he inhaled any of the TCE vapor, Cook said. TCE is a potential cancer-causing chemical.
For many years TCE was used to clean equipment in the C-400 building in the center of the plant complex. A damaged drain that went undetected for years caused thousands of gallons of TCE to leak into the ground. It is the leading source for groundwater contamination, one of the major pollution problems at the plant.
The vaporized TCE was emitted while workers were drilling holes to bury electrodes as part of the pilot project. "We expected there to be some vaporized TCE as we did the drilling operations, but this is at a concentration higher than we've seen in the past," Cook said.
Cook said the worker's chemical-detection monitor sounded an alarm indicating a level of TCE higher than the five-minute peak exposure level allowed under safety rules. "However, the level dropped quickly, and the worker wasn't exposed for five minutes," Cook said.
Officials are reviewing the project and work procedures to determine if additional precautions are needed to protect workers, Cook said.
"We are always very conservative with our safety procedures, and we want to make sure we are doing enough to ensure that workers aren't being harmed," Cook said. He said one concern is that mandating more protective equipment could create a risk of heat-related problems.
Cook said he didn't know when work on the $3.2 million project would resume, but he didn't think it would be much longer.
The electrodes will be buried to heat and vaporize the pools of TCE in the ground. The gases will then be vacuumed and disposed of properly, he said.
Cook said the testing is expected to begin after Jan. 1 and last for 130 days. He didn't expect that this week's shutdown would delay the start of the testing.
At the end of the testing period, officials will determine whether the procedure is working and efficient. "Then, we can either continue the process, make adjustments or stop if it isn't working and take another approach," Cook said.
He said excavating the contaminated soil is not an alternative because much of the contamination is under the building. "The C-400 building is in active use and a key part of USEC's operations," Cook said. "Excavation would be impractical."
Meanwhile, two USEC workers required hospital treatment last week when they suffered heat exhaustion while responding to the release of a small amount of UF6 in one of the process buildings, according to Stuckle.
She said the workers were on their way to the C-333 building wearing protective suits and other equipment to protect them from chemical exposure when they were overcome by the intense heat and passed out.
They were taken to a local hospital to be examined and were back at work in about an hour, she said.
Although the release was very minor, Stuckle said, workers wearing protective clothing always are called to check contamination levels to make sure workers do not face health risks.
The release did not interrupt production.
In another incident last week involving DOE's portion of the complex, a storage trailer was struck by a utility vehicle about the size of a golf cart and knocked into the boundary of a contaminated material storage area, Cook said.
He said the trailer struck a wire metal basket inside the boundary lines. After the incident was reviewed and officials determined there was no risk of nuclear criticality, and no risk to workers or the public, workers were allowed to move the trailer.