A Florida company is giving new meaning to the popular “reduce, reuse, and recycle.” Specifically, it wants to reuse the byproduct produced during phosphate mining to build roads. There’s only one problem: It’s radioactive.
Using radioactive material to build roads in Florida. Earlier this week, the Environmental Protection Agency approved the request of Mosaic, the largest phosphate producer in the U.S., to carry out a small-scale pilot project using various mixtures of phosphogypsum as a road base. The company plans to create four sections of test road with the phosphogypsum road base at its New Wales facility in Polk County.
Federal regulations require phosphogypsum to be stored in engineered piles, known as stacks, to limit the public’s exposure to its radioactive components. Standing hundreds of feet high and covering hundreds of acres, phosphogypsum stacks can resemble small mountains.
In its decision, the EPA pointed out that based on multiple modeling efforts, the risks from Mosaic’s project were “low.” However, the agency said that its approval was restricted to this project and “not any broader use.”
“Any other use would require a separate application, risk assessment, and approval,” the EPA said.
It all starts with a rock. Phosphogypsum doesn’t appear out of nowhere, but rather during the search for another valuable mineral in phosphate rock: phosphorus. Some fertilizers include phosphorus in their products to help plants grow strong roots. To separate the phosphorous from the phosphate rock, companies dissolve the rock in an acidic solution.
This is where the radioactivity comes into play. As explained by the EPA, phosphate rock contains small amounts of naturally-occurring uranium and radium. During processing, most of the uranium ends up in the acid, while the radium ends up in the waste byproduct. And thus, we’re left with phosphogypsum.
Health risk. When phosphogypsum decays, it produces radon, an odorless, colorless, radioactive gas. While radon is present naturally in soils and the atmosphere, it’s generally found in limited amounts that don’t pose a threat to human health. Concerns arise if people are exposed to higher levels of radon over a long period of time.
Prolonged exposure to radon can increase the risk of lung cancer. According to CBS, radon exposure is linked to roughly 21,000 deaths from the disease every year. It is the second cause of lung cancer behind smoking.
Because of its potentially fatal consequences, federal regulators have generally prohibited the use of phosphogypsum in projects. In 1992, the EPA said that using phosphogypsum to build roads could create risks for the construction workers involved and others who decide to build homes near the roads in the future.
However, the EPA does it allow it to be used for agricultural and indoor research under certain circumstances and subject to the agency’s approval.
Backlash. Opponents of the measure said the EPA’s approval was “mind-boggling.” Florida is no stranger to the problems of phosphogypsum. In 2021, a former phosphate mining facility experienced a breach that led to 215 million gallons of toxic water in Tampa Bay.
“That dramatically increases the potential for harm to our road crews and water quality,” Ragan Whitlock, an attorney for the Center for Biological Diversity, said in a statement. “The EPA has bowed to political pressure from the phosphate industry and paved the way for this dangerous waste to be used in roads all over the country.”
The phosphate industry, meanwhile, claims that using phosphogypsum to build roads could be cheaper than the cost of current materials, include limestone rock
“If there is an alternative use for this material, and we don't have to grow or manage these stacks unnecessarily, then why would we not go down that path?” Jackie Barron, a representative from Mosaic, the company that secured the approval, told NPR in 2023.
The future of phosphogypsum roads. Florida passed a law last year that added to the list of approved materials for public road construction, though the state’s Department of Transportation still needs to complete a study on its “suitability” before it can officially be used.
The future of widescale use of phosphogypsum is up the air. The previous Trump administration approved the use of the radioactive material, though the Biden administration later rescinded it. It’s unclear whether the material is on the incoming president’s radar.
Image | Gregory Hayes
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