WASHINGTON — Recent spills of contaminated water from phosphogypsum stacks have added to pressure from a Polk County congressman for the Environmental Protection Agency to allow an alternative use of radioactive gypsum.

Critics of federal gypsum policy expect the EPA to approve an experimental permit to dump 50 tons of the industrial byproduct into a Brevard County landfill. They say that would be a breakthrough in a 15-year feud over why use of the substance is banned with limited exceptions.

The EPA has deemed most gypsum too radioactive for practical use. About 24 gypsum stacks dot Central Florida in piles more than 100 feet high. The stacks grow by about 30 million tons a year.

Contaminated and acidic water from the gypsum stacks creates ponds at the top of the piles. The ponds grow with rain and have spilled into waterways and adjacent land.

“It certainly appears to me that the public health threat and the environmental threat is far greater from these releases than it is from spreading phosphogypsum out in a landfill or a roadbed,” said Rep. Adam Putnam, a Bartow Republican who is pressuring the EPA to reconsider its stacking policy.

Adam Klinger, director of the radiation protection division at the EPA, confirmed the landfill request is further along than any previous application for an onsite experiment. Klinger said the EPA is doing a final review of the application, which was filed in 2000.

Gypsum is a byproduct of processing phosphate into fertilizer. With about 1 billion tons already stacked, alternative uses would not rid Florida of gypsum piles in the foreseeable future. But state environmental officials say reducing stacks would cut contaminated water and the threat of spills. They are bound, however, by EPA rules and are wary of radiation risks.

Putnam and others said spills from two stacks during hurricanes Frances and Jeanne have added leverage for other uses.

The breach at a Cargill Crop Nutrition stack in Riverview during Frances spilled about 70 million gallons of contaminated water into Archie Creek. A much smaller spill from another Cargill stack during Jeanne never reached a waterway. The water is not considered a great threat to human health but is capable of wiping out aquatic life.

The state of Florida expects to spend as much as $160 million cleaning up and maintaining stacks at the abandoned Piney Point site and in Mulberry, the site of a catastrophic spill into Alafia River in 1997.

The landfill permit would allow the Florida Institute of Phosphate Research, a lab in Bartow funded by the state with taxes on phosphate mines, to dump about 50 tons into a small part of the landfill. Researchers say gypsum is a good fuel for microorganisms that decompose trash and could cut the state’s landfill needs in half.

Mike Lloyd, a research director at the institute who has questioned the EPA’s conclusions about gypsum for years, said state officials have approved the experiment as a potential answer to landfill shortages.

Environmental groups are not swayed.

“We have real concerns with spreading out toxins,” said Glenn Compton, chairman of ManaSota-88, a group that forced the original EPA decision in 1989.

AN OLD DEBATE

Radioactive elements in gypsum produce cancer-causing radon gas. The fight has been about whether gypsum poses enough risk to warrant indefinite storage in stacks.

Environmentalists say they trust the EPA’s analysis. But they also say the stacks are a threat that demand stricter state enforcement and consideration when the state approves new mining operations. They blame the phosphate industry for spills.

EPA gypsum policy began with a misstep in 1989. Radon, a natural radiation that can emanate from common soil, became a household word and a political issue in the 1988 campaign year because of estimates that it was killing thousands of people and polluting home basements and schools.

The EPA in 1989 ordered phosphogypsum to be stored in stacks or in spent phosphate mines, which it had determined was the best way to prevent spreading exposure. Phosphate companies had been stacking gypsum for decades but were selling relatively small amounts for road construction and as a soil conditioner.

Mining companies and the institute complained the EPA imposed the ban without thorough scientific analysis and in violation of several rules. They forced the agency to consider other options.

“It was just politically better to say, `We won’t use it for anything,’ ” said Gray Gordon, vice president of Cargill Crop Nutrition.

The EPA studied various scenarios for using gypsum in agriculture, roadbeds and lab experiments. A 1992 report justified most of the original ban, with a few exceptions. Interviews with state and federal officials and researchers and a review of the study and related documents show the EPA:

Made errors when deciding how much gypsum could be safely used in a lab, a limit that was later bumped from 700 pounds to 7,000. The agency denied objections to many other assumptions.

Could not produce mathematical work that underpins the policy when a private consultant for the institute was unable to duplicate the 1992 results using EPA software and assumptions. Douglas Chambers of SENES Consultants in Ontario, Canada, got close to matching many but not all the results after extensive consultation with EPA and an EPA consultant in the mid 1990s, according to a SENES memos at the time.

Lloyd said the slightly lower recalculations suggest EPA policy might be different if it were to redo its math. In any case, Chambers said, the science “should have been a heck of a lot more transparent than that.” An EPA official acknowledged a problem re-creating the results but said the agency has no plans to reopen the report.

Could have allowed broader use of gypsum in agriculture while meeting safety limits but chose not to. Most gypsum was determined to raise cancer risks above the EPA threshold — one to three cancer cases per 10,000 people — under worst-case scenarios if the agency assumed people would build homes on farmland that was treated biennially with gypsum for 100 years and live there for 70 years.

The EPA estimated effects on farm workers, neighbors, people eating food grown in the treated soil and drinking water from nearby wells but did not find those risks too high.

The EPA reported it could allow farm use if it created sliding limits on how much gypsum could be spread per acre depending on how much radium the gypsum contained. The agency decided that would be too complicated and only made an exception for gypsum produced in northern Florida, which has the least radioactivity and was not considered a threat.

Barred gypsum’s use in road construction on the assumption that people might build homes on top of former road sites and live in them for 70 years, putting them at too high a risk for cancer. Other potential hazards were ruled out.

The EPA never produced guidelines for how to apply for exemptions, which gypsum researchers say has allowed the agency to smother requests with unending demands. An EPA official said the agency is now working on exemption guidelines, which are expected to ease future applications.

Environmental groups say the risks outlined in the report are valid and real. The institute, the phosphate industry and other critics disagree.

“Somebody, somewhere, for some reason, has determined that they’re not going to budge on the use of phosphogypsum, and they’ve gotten away with it until now,” said Putnam, who is widely regarded as the instigator of recent EPA movement.

DOWN GYPSUM ROAD?

Critics level many charges at the EPA’s underlying assumptions in the 1992 report. For example, they say the notion that people would build homes on former road sites, let alone live in them for 70 years, is far-fetched. The EPA recently defended its methods as valid in a letter to Putnam.

Advocates of gypsum in road construction say it would save $100,000 per mile of two-lane road. They have tried to moot the EPA’s objections by vowing to impose deed restrictions that would prevent construction on road sites.

Polk County officials and institute researchers tried to get an EPA permit to build a gypsum road in the mid-1990s by promising a deed restriction. But the EPA never approved and the developer built the road conventionally.

State officials did not patently object to a gypsum road experiment but wanted assurances of adequate environmental monitoring.

The institute built a gypsum-based road south of Fort Meade in 1985 and the institute says its data demonstrate safety. The state, however, considers the radiation and pollution data inconclusive. State officials say they want better data, but that would require construction of another road.

Environmental groups don’t want radioactive roads and highways crisscrossing the state, with or without deed restrictions.

“The whole state would be a Superfund site,” said Karen Mulcahy, coastal campaign organizer and gypsum watcher for the Florida chapter of the Sierra Club.

Several environmental groups were unaware of the landfill proposal.

Environmentalists blame phosphate companies for creating the stacks and failing to maintain them. They say Cargill is to blame for recent spills and that fertilizer companies are not taking responsibility for their waste.

“It just costs more money and the industry says, `Let us take the stacks and spread them around,’ ” said Tom Reese, a Florida environmental lawyer who represented ManaSota 88 during early dealings with the EPA and maintains that gypsum is a radioactive nightmare. “You don’t take a hazardous material and spread it around.”

Putnam said the EPA has begun to soften but threatened congressional action. He summoned an EPA official to a hearing in his district that he convened this past spring to challenge the agency’s science.

The EPA has not compared risks to human health if gypsum were used to the environmental risk of spills when it is stacked. Klinger, the EPA official, said the agency would consider such a study if Florida were to seek one.

“We are open to that that kind of dialogue,” he said.

Phil Coram, chief of the Bureau of Mine Reclamation in the Florida Department of Environmental Protection, said a comparison could not be direct but nevertheless is worthwhile because the stacks “pose a major environmental risk.”

“The risk assessments need to address all risks, both environmental and human health,” he said.

Lloyd said approval of the landfill application would be a first step toward showing that gypsum can be used safely. He said the institute would again turn to road proposals if the landfill project moves forward as he expects.

“I think they’re going to do it for the simple reason that I think they’ve had too much publicity,” he said, “too much pressure.”