The Environmental Protection Agency learned last fall that the dust in the 130 acres of slag along Montana Highway 1 to Anaconda could be more dangerous to health than previously believed.
According to an unpublished report, the arsenic in the slag’s dust is about 10 percent more absorbable by the body than EPA thought based on studies done decades ago.
EPA produced the report last fall, but it has not been released to the public. Charlie Coleman, EPA project manager for Anaconda, said the report was created as part of the consent decree negotiations and will be released to the public later in the year. The report was given anonymously to The Montana Standard.
The report states that EPA’s contractor, CDM Smith, took a couple of samples in early fall of last year to test the slag. Both samples were close to the surface of the pile, Coleman said. One sample spot was an undisturbed location closer to Highway 1. The other sample area was near where U.S. Minerals workers were excavating the pile to produce roofing material and abrasive sand-blasting material since around 2013.
The two samples indicated that the arsenic in the slag pile's dust is 28.7 percent absorbable in the body.
EPA originally thought it was 18.3 percent absorbable.
The rest of the arsenic exits the body, according to Coleman.
Despite indications that more of the arsenic is aborbed, Coleman said he didn’t think too much should be read into the new findings. “In the relative context, it’s still low,” he said.
As many observers have pointed out, two samples do not provide conclusive data. A more rigorous study would need to be done to confirm the initial findings and for the results to be considered valid.
Coleman said the EPA is not likely to take further samples to verify if the two-sample information has drawn correct conclusions. Instead, the EPA is planning to partially cap the slag pile. Coleman announced that at a meeting to discuss Anaconda's consent decree negotiations late last month.
Coleman said the new information this report provides will be factored into how the cap is designed.
EPA is also proposing to do tests this summer to see how much of the dust at the slag pile could be blowing off the 26 million tons of old copper smelter waste during warmer months.
"Could it pose a risk to the community?" Coleman asked rhetorically. "We don't think so."
EPA produced the report, in part, because of the issues around U.S. Minerals' worker safety. Occupational Health and Safety Administration (OSHA) fined U.S. Minerals in 2016 $106,800 for 16 violations, including for finding arsenic in the workers' microwave. That case is still pending.
The state health department shut down the small U.S. Minerals slag plant in February because evidence last year indicated employees were being poisoned by arsenic while working at the plant.
The order identified problems such as a lack of showering or working hand-washing facilities or a place for employees to change clothes after a shift. The order also alleged a “lack of appropriate respirator usage” at the site.
According to the World Health Organization, processed arsenic is “highly toxic.” It is carcinogenic, and long-term exposure can lead to developmental effects, diabetes, pulmonary disease and cardiovascular disease as well as cancer of skin, bladder, liver and lungs.
But EPA's concern is the impact to the public, Coleman said. Worker safety falls under OSHA, not EPA, regulations. He said the company is responsible for making sure workers are safe when interacting with toxic materials.
He said the main conclusion this report provided EPA is that the slag is “not much different than other waste at the site, like tailings,” Coleman said.
Coleman didn’t say whether the dust is coming off the slag particles. He said the dust is “a component” of the slag.
Lead in the slag does not appear to be more hazardous than originally thought, according to the report. Only the arsenic in the dust was found to be more potent.
But the report raises questions about exposure to U.S. Minerals workers.
The company reportedly fixed the problems that the Montana Department of Public Health and Human Services laid out in February to justify the cease-and-desist order. Because of fixes, the state health department emailed U.S. Minerals a notice that the company could resume work on a conditional basis last week.
But the company filed a lawsuit in Lewis and Clark County against the DPHHS the same day.
The lawsuit alleges that if the Anaconda plant cannot open the company will suffer irreparable injury. It is not immediately clear if the EPA report has been shared with U.S. Minerals. Mike Johnston, U.S. Minerals president, did not respond to emails seeking comment on the new findings.
The National Institute for Occupational Safety and Health (NIOSH), a federal agency under the umbrella of the Centers for Disease Control, issued a public report in 2016 after conducting its own evaluation of Anaconda's copper slag plant.
NIOSH found that "workers' airborne exposure to arsenic was high at the copper slag processing facility." According to the report, "Five of the six employees sampled (at that time) were exposed to arsenic that approached or exceeded the OSHA permissible exposure limit."
Atlantic Richfield Company, which is responsible for the slag and allows U.S. Minerals to work at the site, did not respond to a request for comment.
Bill Everett, Anaconda-Deer Lodge County chief executive, could not be reached for comment.
DPHHS declined to comment on the report.
“The DPHHS decision to issue a cease-and-desist order was based upon health and safety concerns identified in the order,” DPHHS spokesperson Jon Ebelt said in writing.
Rick Tabish, who announced plans in 2016 that his company would process the slag and turn it into products for the steel and fracking industries, is planning to build a plant just southeast of the slag pile on Mill Creek Highway. Tabish got the necessary permits from the Department of Environmental Quality earlier this year.
Matt Vincent, Tabish's spokesperson, said he couldn't comment on something he hasn't had the opportunity to see. But he added that Tabish will follow all OSHA and other regulatory requirements when his operation is up and running.