Enforcement action required major improvements to reduce release of hydrogen sulfide
According to a Minnesota Pollution Control Agency (MPCA) enforcement investigation, Conagra Brands released hydrogen sulfide (H2S) at higher than allowable levels on more than 2,500 occasions between 2020 and 2022 at its fruit and vegetable processing facility in Waseca, Minn.
MPCA staff review of monitoring data confirmed that the air quality violations occurred during the April-October monitoring seasons each year relating to its operations and treatment of wastewater, and subsequent ambient hydrogen sulfide emissions. Hydrogen sulfide, sometimes called sewer gas, emits a rotten egg smell and can be harmful to human health.
In addition to paying a $1.25 million civil penalty, Conagra Brands was required to spend a minimum of $7 million toward a supplemental environmental project. The company completed the project earlier this year, installing new equipment designed to reduce the amount of hydrogen sulfide it releases. Installation of a new bulk volume fermenter and flow equalization system required:
- Constructing additional pumping stations.
- Installing new piping and air filtration equipment.
- Converting an existing leachate storage tank to an anaerobic selector tank.
The company also agreed that if this project is successful in reducing hydrogen sulfide as anticipated, at the request of MPCA it will share non-proprietary technology, engineering, operation, and maintenance details so that similar technology could be implemented and used by other regulated parties in Minnesota.
MPCA rules and regulations are designed to protect human health and the environment by limiting pollution emissions and discharges from facilities. When companies do not fully comply with regulatory requirements, the resulting pollution can be harmful to people and the environment.
When calculating penalties, the MPCA takes into account how seriously the violations affected or could have affected the environment, and whether they were first-time or repeat violations. The agency also attempts to recover the economic benefit the company gained by failing to comply with environmental laws in a timely manner.
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