The Department of Energy questions whether reports of suspicious smells and symptoms reported by workers at the Hanford tank farms are evidence that they are not protected from chemical vapors.
Eyewitness reports of some workers are not sufficient to require a judge to impose additional safety measures, DOE argued in a federal court filing.
The state of Washington, Hanford Challenge and union Local 598 have asked a federal court judge to immediately require increased worker protections while their lawsuit seeking better worker protection is decided.
Scientific and technical evidence show that more worker protection is not needed, DOE said.
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Potential vapor events are recorded if workers report symptoms or suspicious smells, but the fraction of workers experiencing possible events is very small, DOE said.
From January through July, workers reported suspicious smells or symptoms that could indicate exposure to chemical vapors 54 times, with slightly more than half of the reports for incidents outside tank farm fence lines. The events involved 134 workers, with 96 of them reporting symptoms.
During the same period, workers entered the tank farms 195,000 times, not including workers outside the fence lines.
In some of the reported cases, the likely source of odors was unrelated to chemical vapors associated with waste held in underground tanks, DOE said. In one case, the odor was traced to a rotting orange peel in a garbage can.
Typical symptoms were ones that are commonly reported by anyone in the general population, DOE said, arguing that plaintiffs cannot rely on an argument that reported symptoms are consistent with potentially harmful effects from tank vapor chemicals.
The protective measures in place at the tank farms are protective and are being constantly updated and improved.
DOE court document
Headaches were the most common symptom reported, and also are one of the most common complaints in medicine, DOE said. Another common complaint was upper respiratory symptoms, which are experienced by virtually everyone in the general population.
Specific medical cases submitted by plaintiffs are largely unsupported by medical documentation, DOE claims.
For instance, one worker believed he had developed an occupational lung disease from exposure to chemical vapors. But a chest film showed pleurisy, which is caused by a viral infection rather than toxic inhalation, DOE said.
Some people who have asthma may experience heightened symptoms and obstruction of airflow when they smell common odors, said DOE, relying on a report in the American Journal of Medicine. But asthma, unless severe, does not preclude employment at the tank farms.
Detecting an odor from chemical vapors does not mean that a worker has been exposed to harmful levels of the chemical, DOE said.
Except in rare instances, sampling results from gear worn by workers near their faces show that chemicals were present at less than 10 percent of the limits set to ensure that workers were not exposed to harmful levels, according to DOE.
Workers may smell some chemicals or experience symptoms from them when the chemicals are present below levels that are harmful, DOE said.
Ammonia, a common element of tank vapors, can be smelled at low levels and may cause irritation at low levels. Formaldehyde also can cause eye and nose irritation in some people when it is present in amounts that are well within occupational safety limits, DOE said.
$50 million spent to implement recommendations to date in latest expert report
$45 million spent for supplied air respirators in last two fiscal years
Workers are wearing supplied air respirators within Hanford tank farms, to meet both a union demand and a federal court order. DOE offered to make their use mandatory until a ruling on the preliminary injunction, and the court agreed.
But DOE said in court documents that none of the expert assessments and reviews of tank farm safety in recent years have recommended mandatory use of supplied air respirators.
In addition, none of the expert teams reviewing conditions at the tank farms expressed a concern for their safety while visiting the tank farms or requested supplied air respirators, including when odors were smelled during a National Institute of Occupational Safety and Health tour two months ago, DOE said.
Despite challenging the state to prove that exposure to chemical tank vapors creates an imminent danger to Hanford workers, DOE is working to increase worker protection.
It has spent about $50 million to implement the recommendations of the latest expert review led by the Savannah River National Laboratory and has spent $45 million for supplied air respirators in the last two fiscal years.
“The protective measures in place at the tank farms are protective and are being constantly updated and improved,” DOE said.
The state is asking that in addition to making supplied air respirators mandatory within tank farms, they be mandatory in an area at least 200 feet outside the fence of tank farms if work that disturbs waste is being done within a farm. Disturbing waste increases the risk of a chemical vapor release.
Plaintiffs have not offered a scientific justification for the additional requirements they seek, DOE said.
Making the infrastructure changes to extend the tank farm boundaries into areas where roads and buildings would need to be relocated could delay work in the tank farms by up to three years, it said.