HELENA — Workers at a plant in Anaconda that produces roofing materials and abrasives are exposed to high arsenic levels for prolonged periods, with the highly toxic substance found in the air, on clothing and even on the lunchroom microwave, federal officials said Wednesday.
Air samples taken at the U.S. Minerals plant in October and November found between 1.25 and 4.75 times the permissible exposure limit for inorganic arsenic, according to the U.S. Department of Labor’s Occupational Safety and Health Administration.
Workers wore dust masks that provided inadequate protection, and accumulations of arsenic and lead were found where workers eat, increasing the chances of their ingesting the toxins, OSHA officials said.
None of the plant’s six workers have reported any illnesses, said Art Hazen, OSHA’s area director in Billings. “Arsenic is one of those things, when you deal with a health issue, it usually starts showing up after a few years,” Hazen said.
Previous air samples taken last July also found high levels of arsenic, he said.
The World Health Organization says long-term exposure to arsenic can cause cancer, neurotoxicity, diabetes and cardiovascular disease.
OSHA is proposing more than $106,000 in fines for 16 serious violations related to the arsenic levels. The agency classifies a serious violation as one that could result in serious physical harm or death.
The agency also proposed the company immediately protect the workers with respirators until it reduces the level of arsenic in the air.
The Dyer, Indiana-based company has 15 days to contest the citations. Company President Michael Johnston released a statement saying U.S. Minerals disagrees with the alleged violations and proposed fines.
Separate tests conducted before and after OSHA’s inspection found arsenic levels below the limits, Johnston said.
“We have reviewed the citations and intend to challenge the allegations, citations and fines based on all of the data available,” Johnston said in the statement. “We will continue to work to improve the work environment to insure that our employees are protected from any and all safety and health hazards.”
U.S. Minerals has been in OSHA’s Severe Violator Enforcement Program since 2010.
The federal agency has found safety violations in U.S. Minerals plants in Wisconsin, Illinois and Louisiana. OSHA officials said last year the company had been inspected 18 times since 1983, resulting in the multiple safety and health violations.
The Anaconda plant opened in 2013 on a slag pile of materials from copper smelting that contains arsenic and lead. Iron silicate granules from the slag are processed into roofing granules and abrasives.