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EPA Approves Use of Phosphogypsum in Road Construction

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WASHINGTON (October 14, 2020) — Today, U.S. Environmental Protection Agency (EPA) Administrator Andrew Wheeler approved a request from The Fertilizer Institute (TFI) to allow phosphogypsum to be used in government road construction projects.

“Allowing the reuse of phosphogypsum shows EPA’s commitment to working with industry in a way that both reduces environmental waste and protects public health,” said EPA Administrator Andrew Wheeler. “The approval of this request means that phosphogypsum, which already requires significant engineering and regulatory controls to be disposed of in stacks, can now be put to productive use rebuilding our nation’s infrastructure. This demonstrates President Trump’s commitment to “win-win” environmental solutions.”

“TFI strongly supports and appreciates EPA’s science-based review and decision to allow the limited use of phosphogypsum, a by-product of phosphate fertilizer manufacturing. This decision strengthens the industry’s sustainability efforts and long term environmental stewardship,” said TFI President & CEO Corey Rosenbusch.

Phosphogypsum, a byproduct material of phosphate fertilizer production, is by regulation disposed of in massive, above-ground piles, commonly called “stacks.” Each “stack” can span thousands of yards, be higher than a football field, and contain approximately 70 million tons of phosphogypsum. By finding a new way to use phosphogypsum, EPA is helping create a sustainable path to improve the environment while allowing for responsible reuse and recycling of a valuable byproduct.

The U.S. produces approximately 20% of the world’s phosphogypsum. In countries where reuse is practiced – such as road building, construction material, fertilizer, and landfill cover – up to 20% of annual phosphogypsum production is diverted from stacking to other uses. While the approval of TFI’s request does not mean that phosphogypsum will become widespread in roads, it allows state and local governments to investigate the opportunity to use phosphogypsum in appropriate road construction projects.

Risk analyses conducted by TFI, and reviewed by the EPA, demonstrate that the proposed use of phosphogypsum in road construction is as protective of public health, in both the short- and long-term, as is disposal of phosphogypsum in a stack. TFI’s risk assessment and this approval reflect the most significant efforts made on the topic of alternate use for phosphogypsum since they early 1990’s.

This approval sets limits and requirements to protect public health and requires public notice of phosphogypsum use in roads. To protect public and worker health, there are restrictions on the proportion of phosphogypsum in the mixture that can be used in a road project. The terms and conditions also impose restrictions on how and where phosphogypsum can be incorporated into the road design. For example, a road constructed with phosphogypsum may not be abandoned and used for other non-road purposes. Government agencies proposing to construct roads using phosphogypsum must still comply with other applicable laws and regulations, including use of appropriate technical standards and specifications.
For more information on how EPA protects the public and the environment from the hazards of radioactive materials found in phosphogypsum, please visit Subpart R: National Emissions Standards for Radon Emissions From Phosphogypsum Stacks.


Phosphogypsum is a byproduct material of phosphate fertilizer production. It is regulated for the presence of radium-226, a naturally occurring radioactive substance that produces radon gas, a hazardous air pollutant.

The Clean Air Act requires the disposal of phosphogypsum in stacks, except for limited agricultural and research uses. The Clean Air Act also provides a procedure to request authorization to use phosphogypsum for other uses, and that the Assistant Administrator may approve such a request if the alternative uses fall below risk thresholds.