Mosaic secures permit to study underground injection of fertilizer wastewater in Florida

The Mosaic Company has obtained state approval to drill an exploratory well in Polk County, Florida, as part of a plan to evaluate the feasibility of injecting wastewater from fertilizer production deep underground.

The Florida Department of Environmental Protection (DEP) issued a draft permit in August allowing Mosaic to drill a Class V exploratory well at its Bartow facility. The permit does not authorize disposal but permits geological testing at depths of about 8,000 feet to determine whether the site is suitable for long-term wastewater storage.

Mosaic said any wastewater would have to be treated to ensure compatibility with the saline rock formations at that depth. “There’s not going to be raw process water injected into the ground — that’s not going to happen,” company hydrologist David Brown said, stressing that Florida law prohibits the underground injection of hazardous fluids. He noted that more than 200 similar wells already operate in the state and that permits require monitoring and periodic re-verification of well integrity.

If Mosaic later applies for and secures a Class I permit, it would mark the first time an active fertilizer plant in Florida is allowed to dispose of its production wastewater underground. A previous injection permit was granted in 2021 for the closed Piney Point facility in Manatee County after a major wastewater release into Tampa Bay, but that site had ceased operations two decades earlier.

Environmental organizations sharply criticized the move. The Center for Biological Diversity and local advocacy group Manasota-88 warned that deep well injection poses irreversible risks if wastewater containing contaminants such as arsenic and cadmium leaks into groundwater. They also pointed to Mosaic’s past environmental issues, including sinkholes at its Mulberry site.

“This really just looks like another page in the book about our failing regulatory accountability for really dangerous waste here in the state,” said Elise Bennett, Florida director for the Center for Biological Diversity. Manasota-88 chairman Glenn Compton added, “Once we learn there is a problem, it’s too late to do anything about it.”

The DEP has faced longstanding criticism from environmental groups for what they see as lax oversight of Florida’s phosphate and fertilizer industry. Two pending lawsuits from the Center for Biological Diversity challenge federal approval of phosphogypsum road projects and call for classifying the fertilizer byproduct as hazardous waste.

Mosaic maintains that deep well injection is a safe and highly regulated process. Environmental groups counter that Florida’s geology makes it especially vulnerable to contamination and argue that alternative disposal methods should be prioritized.