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Even small amounts of mercury can have big impacts. Minnesota is a national leader in keeping mercury out of the environment, and was one of the first states to develop a statewide mercury reduction plan.

The MPCA prepared a report that evaluated the sources of mercury and quantified the reductions needed to meet water-quality standards. It includes strategies to keep mercury in water discharges below 24 pounds per year, and mercury air emissions below 789 pounds per year. Learn more:

The MPCA adopted Minn. R. 7007.0502 to accomplish the reductions outlined in the TMDL:

  1. Mercury reduction plans. Affected facilities must prepare mercury reduction plans.
  2. Performance standards. Certain facilities are required to meet performance standards for mercury control.
  3. Emission inventory for mercury. The largest sources of mercury submit an annual mercury emission inventory to the MPCA.

Facilities that are a “mercury source” by definition in the rule and emit more than 3 pounds of mercury (or 5 pounds for industrial boilers) must complete a mercury reduction plan.

Mercury and ferrous mining

Ferrous mining or processing facilities are required to reduce mercury emissions by 72% from 2008/2010 emission levels by January 1, 2025.

Two facilities submitted plans that meet the emission-reduction requirements:

Two facilities submitted plans with proposed reductions of less than 72%:

Four facilities asserted that no further reductions are technically achievable and submitted alternative plans proposing to conduct further literature and engineering review beginning in mid-2020:

Other sources of mercury

Minnesota facilities with air-quality permits that emit mercury over certain thresholds were also required to submit mercury reduction plans. American Crystal Sugar in East Grand Forks proposed ways to limit mercury emissions from its two boilers to less than 10 pounds per year, to comply with Minnesota rules.

Gerdau Ameristeel, an iron and steel melter, proposed strategies for reducing its mercury emissions to less than 35 milligrams per ton of iron/steel produced, as required by Minnesota rules.

Emissions inventories

Oversight committee updates

In 2008, stakeholders recommended that an oversight group be established to review and evaluate progress toward achieving the goals of the Statewide Mercury TMDL, provide advice to the MPCA on implementation, and determine if additional measures are needed to meet these goals. This group has met annually since 2009.

For more information about the oversight committee and/or documents from previous meetings, contact MPCA Statewide Mercury Reduction coordinator, Hassan Bouchareb, 651-757-2653.


There was no group meeting in 2022.