Fertilizer giant Mosaic wants to start testing phosphogypsum in roads, records show

Tampa-based fertilizer giant Mosaic is seeking approval from federal environment regulators to begin testing the use of phosphogypsum — a mildly radioactive byproduct from the company's phosphate mining process — in a roadway at its New Wales facility, according to records reviewed by the Tampa Bay Times.

Correspondence between Mosaic and the U.S. Environmental Protection Agency offer a glimpse into the Fortune 500 company's controversial plan to roll out a "small-scale" pilot project at its Mulberry plant using phosphogypsum as an ingredient in three 200-foot sections of road, records show.

If approved, the pilot project would mark the first time the EPA has green lit phosphogypsum use since its 2020 approval, and subsequent reversal, of a request to use the byproduct in American roads.

The EPA is reviewing Mosaic's plan and expects a decision on next steps in the coming months, according to spokesperson Melissa Sullivan.

Mosaic first submitted its proposal to the agency in March 2022, records show, nearly a year before the Florida legislature introduced a bill that would allow the Florida Department of Transportation to study the use of phosphogypsum in road construction. That bill, which was lobbied by Mosaic, has been approved by both the Florida House and Senate but has yet to be sent to Gov. Ron DeSantis for his signature.

One of Mosaic's main objectives is to collect data from a road "where phosphogypsum is exposed to real-world conditions," according to a letter sent to the EPA from Pat Kane, a Mosaic executive.

The proposed test road on Mosaic's property would be made up of sand with a 10-inch base containing up to 50% phosphogypsum. Monitoring wells will study the health of the ground beneath the test road for 18 months.

Phosphogypsum contains radium-226, which emits radiation during its decay to form radon, a potentially cancer-causing, radioactive gas, according to the EPA.

In an email to the EPA sent March 6, Karen Bennett, a lawyer representing Mosaic, said the company was disappointed with the pace of the federal agency's review, and said the proposed project "is a part of a much broader environmental solution in which we have made significant investment." Bennett has followed up with the EPA at least four times since January, emails show.

Mosaic spokesperson Jackie Barron elaborated in an emailed statement to the Times: "Globally, phosphogypsum is used extensively in a variety of safe and innovative ways. At Mosaic, we believe there is great value in the principles of a circular economy whereby materials formerly viewed as wastes can be used or recycled beneficially," Barron wrote.

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Until a complete request for the use of phosphogypsum is approved by the EPA, phosphogypsum can't be used in road construction. In 2020, at the request of industry group the Fertilizer Institute, the EPA changed a decades-old policy to allow limited recycling of phosphogypsum in roads. But when the agency switched to the Biden administration, it rolled back the controversial decision claiming the Institute's application was missing important information.

The Florida Industrial and Phosphate Research Institute estimates roughly 1 billion tons of phosphogypsum are stored in about two dozen "stacks" across Florida, though that figure is undated. The group says 30 million new tons of phosphogypsum are generated each year. Mosaic provided a fact sheet saying 1.7 billion tons are stacked across the nation.

In 2016, a sinkhole measuring 152 feet wide formed beneath the stack at the New Wales facility and resulted in 215 million gallons of contaminated water draining into the aquifer below.

Environmental organizations across Florida have decried the use of phosphogypsum in Florida roads, claiming it's a mechanism for Mosaic to cash in on a byproduct that may be harmful to human health.

"Paving roads with radioactive phosphogypsum is a threat to the health and safety of Floridians and our water quality," said Ragan Whitlock, a staff attorney at the Center for Biological Diversity. "The EPA should deny Mosaic's request to re-use its toxic waste in roads near the problematic New Wales facility. This is yet another industry attempt to generate revenue from its toxic waste at the expense of public health."

The EPA's review of Mosaic's pilot project is independent, Sullivan said, from the Florida legislation still awaiting a decision from DeSantis.

The project would still require state permits, though. The Florida Department of Environmental Protection has already met with Mosaic twice, where the company outlined their concepts for the pilot project, state spokesperson Alexandra Kuchta confirmed.

Mosaic has funded the University of Florida's Timothy Townsend, a professor at the school's Department of Environmental Engineering Sciences, to develop the plans and design for the proposed pilot project.

In an interview with the Times, Townsend said his work with Mosaic is necessary to determine whether using phosphogypsum is a safe and feasible approach to road construction.

"The alternative is putting these things in big giant stacks," Townsend said. "And they keep getting bigger."

Townsend said he understands why "someone might have some concerns" about the potential health risks, but "every single product we use on a road base has some potential human health risks," he said.

There needs to be a balance between saving natural resources used for roads, and also looking toward using waste products like phosphogypsum, Townsend said.

"The only way we can determine that is to do research and to do testing," Townsend said. "It makes sense to look for waste products and explore whether there are feasible and environmentally safe options."

Tampa Bay residents are familiar with the environmental risks tied to gypstacks: In 2021, roughly 215 million gallons of tainted water from the Piney Point fertilizer site were sent into Tampa Bay as a precaution due to fears that a leak in a reservoir could trigger a massive flood, endangering homes and businesses. The release of contaminants may have fueled a sweeping red tide, and likely contributed to the bay's declining seagrass.

Records indicate the waste byproduct is a touchy subject among EPA staff.

In an email to other other staff members March 3, Jonathan Walsh, a physical scientist at the agency's Radiation Protection Division, wrote "everything related to PG makes me really nervous right now." He used a common acronym referring to phosphogypsum.

Glenn Compton, chair of the local environmental advocacy group ManaSota-88, said he's concerned that reusing the byproduct in construction could harm Floridian's health.

"A small pilot project is certainly not the answer to getting rid of the waste that they produce," Compton told the Times. "This is a way to increase their bottom-line profit — but that would come at the cost of the public's health and the environment."