Mosaic Fertilizer failed to address serious chemical safety risks raised in its own internal warnings over six years at one of its St. James plants, federal regulators say.

The company and its subsidiary also failed to properly test high-pressure ammonia piping and other equipment known to be at risk of corrosion, regulators found. And in another instance, a worker was assigned to a control board without initial training on a new process being used at the ammonia plant, regulators reported.

Those violations were among nine alleged Clean Air Act infractions recently settled with the U.S. Environmental Protection Agency by Mosaic and its sister company, Tampa Port Services. EPA discovered the problems after an inspection in 2022 of the Faustina complex along the west bank of the Mississippi River.

Mosaic and Tampa Port agreed to pay $217,085 in civil fines and spend another $100,000 on environmental projects in St. James Parish, including new air monitoring. The deal with the EPA, signed in January, did not require the companies to admit the violations.

The breakdowns in equipment testing, employee training and safety procedures occurred between 2014 and 2021, the EPA said.

State environmental regulators already had been scrutinizing the facility for more than a decade.

In 2013, company officials told the state Department of Environmental Quality that they would roll out a new program to catch aging and corroded equipment, records show. But when EPA inspectors showed up in 2022, they found that while Mosaic was conducting the reviews it promised DEQ, it often wasn’t acting on them.

EPA found the company hadn't rectified 27 of its own safety findings for its Faustina plant. Those unfinished fixes were called for in internal Mosaic reports from 2016 to 2021.

Inspectors also found about half of the improvements sought in a 2016 internal safety analysis took too long?— more than 2? years — to complete.

"Preventing chemical accidents is one of the most important goals of the Clean Air Act, which can only be fulfilled with the full participation and commitment of owners and operators of industrial facilities," Earthea Nance, EPA's regional administrator, said in an agency statement about the settlement.

The Faustina plant handles a variety of flammable or hazardous chemicals, including syngas, ammonia, molten sulfur and phosphoric and sulfuric acids, according to permit records.

Jackie Barron, a Mosaic spokeswoman, said the company works "rigorously to meet or surpass all safety and environmental regulations under which our facilities operate."

"We work closely and are in constant conversation with our regulators at all levels of government. Our priority is always the safety of our employees and the communities we call home," she said.

The federal fines come about two months after a Mosaic agreement with DEQ to pay $24,650 in fines and settle state air quality violations going back a decade and a half.

Mosaic was in discussions with DEQ over that settlement for more than a decade, Barron said. The company is also seeking an overall settlement of five other DEQ enforcement actions, according to agency records.

The new EPA settlement requires the companies to install two emergency generators for the parish homeland security department and ammonia gas monitors around the fertilizer complex.

The company must monitor the new emissions network for at least two years under the EPA deal. The move will add 11 monitors to an existing Mosaic network and include alarms that warn the plant.

At Faustina, Mosaic processes dry agricultural fertilizers that also are used as fire retardants. Its subsidiary, Tampa Port, runs an adjacent facility that makes anhydrous ammonia, another fertilizer component.

The complex operates in conjunction with Mosaic's Uncle Sam plant, which is across the river from it.

David J. Mitchell can be reached at or followed on Twitter, @newsiedave.