Florida is considering a project proposal to test an unconventional road-building material. This material is phosphogypsum, which is a radioactive byproduct of phosphate mining. Phosphogypsum is a waste product created during the production of phosphorus, an essential nutrient in fertilizers.
     To extract phosphorus from ore, phosphate rock is dissolved in acid. This process separates uranium, which winds up in the acid. Radium remains in the leftover material. This remaining waste is referred to as phosphogypsum.
     Radium naturally decays and releases radioactive radon gas which is known to increase the risk of lung cancer when people are exposed to it for extended periods.
     Because of these risks, federal regulations require phosphogypsum to be stored in specially designed structures called engineered stacks. These stacks are huge, often hundreds of feet tall and cover large areas. They resemble small mountains. The purpose of these stacks is to keep the radioactive material contained and to limit human exposure in order to maintain public safety.
     A few days ago, the Environmental Protection Agency (EPA) approved a pilot project by Mosaic, the largest phosphate producer in the United States. The Mosaic project involves building four test road sections at Mosaic’s New Wales facility in Polk County, Florida. They will be using phosphogypsum as a road base.
    The EPA rated the project’s risks as “low” based on multiple modeling efforts. The approval is limited to this specific project. Any broader applications in road building would require additional evaluations and regulatory approvals.
     Radon is an odorless and colorless gas and it poses significant health risks when present at elevated levels. According to the Center for Biological Diversity, it is the second leading cause of lung cancer in the U.S. It is responsible for about twenty-one thousand deaths annually. Prolonged exposure, especially near phosphogypsum-based roads, could pose a threat to public health. Federal regulators have historically banned phosphogypsum in construction due to the presence of this radioactive risk.
     In 1992, the EPA mentioned potential dangers for construction workers and future residents living near roads containing phosphogypsum. Exceptions to the ban have been made for controlled agricultural and research uses.
     Critics have argued that the EPA’s approval of the Mosaic project prioritizes industry interests over public safety.
     Florida has faced problems with phosphogypsum in the past. In 2021, a breach at a former phosphate mining site released 215 million gallons of toxic water into Tampa Bay. This resulted in environmental and public health crises.
     Ragan Whitlock is an attorney for the Center for Biological Diversity. He said, “That [release] dramatically increases the potential for harm to our road crews and water quality.” He accused the EPA of yielding to political pressure from the phosphate industry.
     Environmentalists also point out the long-term implications of using radioactive material in infrastructure. Concerns include radon exposure for road workers and communities living near phosphogypsum roads. There is also concern about potential contamination of water sources.
     Jackie Barron is a Mosaic representative. He emphasized the cost advantages of using phosphogypsum compared to traditional materials such as limestone rock. In 2023, he said, “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?”
     Florida passed legislation last year that expanded the list of materials allowed in public road construction. However, Florida’s Department of Transportation must still review phosphogypsum’s suitability before its widespread adoption.
     The phosphogypsum issue has experienced political shifts. The first Trump administration approved phosphogypsum’s use in roads. However, the Biden administration later reversed this decision. It remains unclear how the incoming Trump administration will address the material’s future.
     Mosaic’s pilot project may pave the way for innovative recycling. However, it also highlights the need for careful risk assessment. The debate over phosphogypsum use in road construction highlights the broader challenge of balancing economic benefits with environmental and public health concerns.
     Florida’s experiment may serve as a critical case study for the rest of the country. Whether the Mosaic project turns out to be a breakthrough or a misstep, the outcome will have a lasting impact for road construction and radioactive waste management in the U.S.

Mosaic