A spokesman for Harsco Corp. said in an email that the levels of beryllium and arsenic in the company's slag-based abrasives are no more than what's found in everyday soil.
"The fact is that all abrasives produced from natural sources are likely to contain trace amounts of metals and other elements," Harsco's Ken Julian said. The levels are so low they're not required to be listed on the product labels or on safety data sheets, he said.
Moreover, Julian said, the slag is "vitrified" or heat-hardened in processing so that any impurities are "encapsulated" or locked in the grains of blasting grit.
But Adam Finkel, a University of Pennsylvania law professor and former OSHA official who dealt for years with beryllium exposure issues, said testing has shown that when blasted via high-pressure nozzles against a surface, slag particles break down into dust, increasing the potential for exposure to contaminants.
Though workers are advised to wear air-fed respirators and protective clothing when doing blasting, Finkel said he'd seen cases of people with beryllium disease whose only exposure came from inhaling dust brought home from work by their spouses in their hair or on their clothes.
He credited Paul J. Mellon, president of Novetas Solutions in Philadelphia, which makes a competing blasting grit from recycled glass, with prodding OSHA to launch its investigation into whether slag-based hazards are properly disclosed.
"The sad part is that we really are talking about human health, not just workers but retail consumers," Mellon said.
Slag-based blasting grit is sold at building supply stores in the Baltimore area. A 50-pound bag of "Black Beauty," Harsco's brand name for its coal slag abrasive, bought for $9 at a local lumber store, does not mention arsenic, beryllium or any other contaminants on its label. The bag does advise anyone doing blasting, though, to wear protective gear, including an air-fed respirator, to avoid inhaling dust.
Fran Cohen, industrial hygienist at the Coast Guard's ship repair yard in Curtis Bay, said her facility also has shifted to blasting mainly with water, but does work with what she called "fused" coal slag that she said had been refined to remove contaminants. Blasting using slag is generally done inside a large booth to contain the dust, she said, and workers wear protective gear.
Cohen pointed out that many workplaces had shifted years ago to coal and copper slag for blasting, after it became clear that blasting with sand was exposing workers to harmful silica, which can also cause serious lung disease if inhaled.
Brian Burns, general manager for Opta's plants in Virginia and Maryland, said the company is retesting its slag-based products "to make sure we have good quality." If the results show contaminants at levels required to be disclosed, he said, they'll be listed.
The Baltimore plant at 4500 E. Fayette St. had processed coal slag until about a year ago, when the company shifted its stockpile to its Norfolk, Va., facility. Burns said the move was made after the Maryland Department of the Environment ordered the company to take steps to control rainfall runoff and windblown-dust from the coal slag it had stockpiled there. State regulations governing the handling and storage of coal-combustion waste byproducts require precautions to keep contaminants from seeping into ground water or nearby streams.
The Baltimore plant now processes copper slag shipped in from Japan, Burns said, which is sold under the brand name Ebonygrit. The black-looking slag is piled at the back of the company's lot, which is about two blocks from residences. Burns said the company complies with all state regulations.
"We do all the things we need to do to make sure it doesn't get out from our property to a stream or a neighbor," Burns said.
The OSHA spokesman said the agency is aware of "potential violations" involving manufacturers' failure to list the metals on the "material safety data sheets" accompanying the products, which are required under federal law to notify workers of potential hazards.
Lawder, declined to say what steps have been taken to investigate whether slag contaminants are properly disclosed, though in the statement he provided weeks ago he said it would be referred to the agency's field offices.
"It looks like they are doing the right thing," said Public Citizen's Feldman. But he pointed out that OSHA has had information for some time showing unsafe beryllium levels when blasting with slag.
"They've known about it, they just haven't enforced it," he said.