It’s been one year since the state Legislature passed HB 1191 regarding the use of phosphogypsum in road construction, or what critics of the proposal dubbed “radioactive roads.”
The law required projects using phosphogypsum to get approval from the federal Environmental Protection Agency before beginning, and for the Florida Department of Transportation to conduct a study on the material’s use as a road base. It did not specifically approve its use in any projects.
University of Florida researcher Timothy Townsend said that the law was misinterpreted.
“If the public were to think that when that legislation was passed, that all of a sudden there's going to be lots of phosphogypsum being used, that legislation didn't direct any of that. It just simply said DOT do a study,” he said. “And when you want to use this material, make sure that you get EPA approval to do it.”
The EPA already carefully regulates the use of phosphogypsum, a byproduct of the phosphate mining industry. A majority of the United States’ phosphate mining for fertilizer occurs in Florida, mostly in the Tampa Bay area, and the Mosaic Company does much of it.
Phosphogypsum, or PG, emits a small amount of radon, a radioactive material. Most of the PG in the US is stored in large piles called “gypstacks.” There has been a push in recent years to find ways to reuse this material, such as in road construction. However, the EPA currently does not allow it to be used this way.
“I think a natural thing to explore is, can that material be recycled?” said Townsend, the Jones, Edmunds & Associates, Inc. professor in UF’s Department of Environmental Engineering Sciences. “But with all these materials, they need to be recycled only if it can be done in a safe way and protective of human health and the environment.”
A grant from the Mosaic Company funded Townsend’s research at UF on phosphogypsum. The 2023 study looked at the plausibility of using PG as a road base, the part of the road that goes under the pavement to provide structure and support. Townsend and his colleagues found that it had promise as a road base when combined with other materials, up to a 50% mixture. However, they also recommended that a field study should be done.
“Laboratory tests are one thing. Actually going out and building it is another thing, which is why we recommended the pilot study,” Townsend said.
In 2020, the EPA moved to allow the use of phosphogypsum in roads, but after backlash from environmental groups across the country, the agency rolled back its decision in 2021. Many other countries around the world use PG in roads.
EPA spokesperson Angela Hackel wrote in an email that the Mosaic Company requested in December 2021 to conduct a pilot project using PG as a road base as the next step after working with UF researchers.
The pilot project, according to Townsend, would be a small strip of road on one of Mosaic’s properties that would test the material in actual real-world conditions, as well as monitor potential groundwater seepage. As far as he’s aware, Townsend said this is the only project currently proposed to the EPA.
After a back and forth that lasted over two years, with the agency sending Mosaic questions for revision multiple times, the EPA deemed Mosaic’s request “complete” earlier this year. According to Hackel, the agency expects to have a proposed decision by the end of the year.
If the EPA looks over the proposal favorably, the request will then be opened for public comment. Once public comment is complete, Hackel said, the EPA will then issue a final decision on whether to approve or deny Mosaic’s request. Only then can the company begin its project.
HB 1191 also required the Florida Department of Transportation to conduct a study on the suitability of PG as a road construction material. The study analyzed a number of previous research studies on the topic.
It came to the conclusion that PG faces challenges, such as its variability in quality and sensitivity to moisture, but shows promise when used as part of a mixture or in combination with other materials. The study also recommended further laboratory and field testing be done to address gaps in the existing research – for example, in testing its long-term performance.
As the FDOT study finished in April, spokesperson for the department Michael Williams said in an email that the state cannot take further steps to actually begin using phosphogypsum in road construction until the EPA changes federal regulations.
Mosaic spokeswoman Jackie Barron declined WUFT’s request for an interview, saying in an email there’s “nothing more to share” until the EPA makes a decision.
Copyright 2024 WUFT 89.1
