Allied-Signal Inc., which is spending up to $100 million to clean its old chrome chemical works on Baltimore's waterfront, is lobbying regulators to relax rules on how much contaminated dirt must be removed from the site.
No decision has been announced. But a Maryland environmental official says the soil cleanup requirement is likely to be eased, despite objections from environmentalists and from New Jersey officials, who have been dueling with Allied over cleaning up contaminated sites in that state.
The dispute is a classic one in hazardous waste cleanups: How much chromium in soil is safe? Scientists cannot say for sure. But for the public and for Allied, the stakes are high.
One form of chromium is an essential mineral in the human diet, but the hexavalent form can cause cancer if inhaled. It also is a powerful skin irritant that can cause persistent rashes and sores.
Both forms of the metal riddle the 19-acre site near Fells Point, which was used by various companies to process chrome ore from 1845 until 1985, when Allied-Signal closed its plant.
Allied hopes to recoup the costs of cleaning up the old chrome plant by building up to $200 million worth of housing and offices on the site once the cleanup is finished, which is scheduled for 1995.
Under a 1989 agreement with the U.S. Environmental Protection Agency and the Maryland Department of the Environment, Allied has been dismantling the old factory, decontaminating what it can and shipping off the rest for disposal in a hazardous waste landfill.
The company plans to seal most of the chromium in the soil by laying down a 7-foot "cap" of clay, gravel and heavy plastic sheeting. A barrier also will be installed around the shoreline to protect the Patapsco River from leakage, which was estimated to be 62 pounds of chromium a day.
But Allied has objected to a requirement by EPA and the state that soil on some parts of the site must be excavated and treated if it has more than 10 parts per million of hexavalent chromium.
That cleanup standard was based on studies done for New Jersey. No one knows what, if any, amount of hexavalent chromium can cause cancer if inhaled.
But some laboratory studies show that as little as 10 parts per million of the metal can trigger rashes in allergic individuals.
William Blank, Allied's senior project manager in Baltimore, contends that standard is "unrealistically stringent." Studies done for Allied suggest that only a small fraction of the chromium in soil would attack a person's skin, meaning higher levels of contamination would cause no harm.
"We didn't want an artificially low standard set, which would be picked up and applied to other locations," said Mr. Blank.
The issue could affect Allied's cleanup costs not only in Baltimore but in New Jersey, which has the nation's worst chromium contamination problem. New Jersey officials say that chromium-laden waste from factories owned by four companies, including Allied, was dumped in more than 150 places in that state, including neighborhoods and playgrounds.
Allied, which is headquartered in Morristown, N.J., has balked at participating in a cleanup in that state, though two other companies have agreed to spend $130 million to deal with some of the sites.
Allied originally contended that at its Baltimore site, it should be allowed to leave soil containing up to 400 parts per million of chromium, or 40 times the limit set by the government.
The company's position was challenged by environmentalists and by New Jersey officials, whose research was originally relied upon by the EPA and by Maryland to set the soil cleanup level.
Dru Schmidt-Perkins, Maryland director of Clean Water Action, an environmental group, called Allied's effort to relax the cleanup requirement for such a toxic metal "very, very dangerous."
Easing Allied's soil cleanup requirement "would be an unfortunate precedent," said Dr. Alan Stern, a research scientist with the New Jersey Department of Environmental Protection and Energy.
Environmentalists and New Jersey officials both acknowledge there is scientific debate about how chromium mixed with soil affects skin.
But until more is known, they contend, regulators should set the limit as low as possible to be safe.
"Everybody wants to know what level [in soil] is dangerous," said Jacqueline Savitz, a toxicologist with the Chesapeake Bay Foundation. "Based on studies, we don't know. There's a lot of uncertainty. The bottom line is . . . we should err on the side of conservatism."
The EPA has not made a final decision on Allied's request, according to Ruth Podems, a spokeswoman for the agency's regional office in Philadelphia.
But Alvin Bowles, Maryland's chief of hazardous waste regulation, said that EPA and the state are likely to agree to ease the requirement slightly. That would allow soil to be left untreated if it contains up to 50 parts per million of hexavalent chromium.
That change should not affect the safety of developing the old Allied site, Mr. Bowles said.
Mr. Bowles said he doubts that chromium levels in the soil along Wills Street, where cleanup would be required, exceed 10 parts per million, anyway.