Rulemaking: Wild Rice Sulfate Standard

What is the wild rice sulfate standard?

In 1973, Minnesota’s wild rice sulfate standard was adopted by the Minnesota Pollution Control Agency (MPCA) and approved by the U.S. Environmental Protection Agency (EPA) under the Clean Water Act. Minnesota’s wild rice sulfate standard limits sulfate to 10 parts per million (mg/L) in wild rice waters.
Images used in community organizing to preserve wild rice sulfate standard, WaterLegacy.
MPCA’s enforcement of the wild rice sulfate standard to control sulfate discharge was weak and sporadic for decades. In 2010, when EPA told MPCA that the standard must be enforced under the Clean Water Act, mining interests and their supporters attacked the standard. WaterLegacy engaged in an eight-year advocacy and organizing campaign to preserve the wild rice sulfate standard.

What efforts were made to weaken or eliminate the standard through rulemaking?

In 2011, the Minnesota Legislature passed a session law directing the MPCA to engage in rulemaking to amend the wild rice sulfate standard. This session law appropriated $1.5 million for new scientific research and a task force run by the MPCA, anticipating that the rule would be amended to repeal or weaken the wild rice sulfate standard. This rulemaking process took seven years – from 2011 through 2018.

Alice White Cadotte, LCO, 1941, “Knocking Rice.”

What was the result of the rulemaking process?

Minnesota’s wild rice rulemaking process funded scientific research that confirmed the wild rice sulfate rule is reasonable and necessary to protect wild rice.

In 2017, MPCA proposed an amended rule to repeal the wild rice sulfate standard and replace it with an equation that allowed more sulfate pollution if there was a high level of iron in the affected waters. MPCA also proposed to identify approximately 1,300 waters as wild rice waters, but exclude some of the wild rice waters identified by tribes and the Minnesota Department of Natural Resources scientists, including waters downstream of existing and proposed mines.

WaterLegacy, tribes, and independent scientists opposed MPCA’s proposed rule on several important grounds:

  • MPCA’s proposed equation would fail to protect wild rice, especially in mining regions.
  • Additional sulfate allowed by MPCA’s proposed rule would increase mercury methylation and contamination of fish.
  • Excluding some Minnesota wild rice waters from protection would violate the federal Clean Water Act.
In January 2018, after contested case hearings, community testimony, written comments, and expert opinions, MPCA’s proposed rule was rejected by Administrative Law Judge LauraSue Schlatter, with the approval of the Chief Administrative Law Judge in January 2018. MPCA then attempted to challenge the Administrative Law Judge’s decision, but its challenge failed. MPCA withdrew its proposed rule to repeal the wild rice sulfate standard on May 7, 2018.

The wild rice rule adopted and approved in 1973 to limit sulfate to 10 parts per million (mg/L) remains in effect.

What did the Administrative Law Judge decide?

The Administrative Law Judge agreed with WaterLegacy and tribes that the MPCA’s proposed rule would fail to protect wild rice and improperly restrict wild rice waters, violating the Clean Water Act. The Administrative Law Judge:

DISAPPROVED repeal of Minnesota’s existing wild rice sulfate standard of 10 mg/L, stating:

The Administrative Law Judge DISAPPROVES the proposed repeal of the 10 mg/L sulfate standard at Minn. R. 7050.0220, subps. 3a, 4a, 5a, 6a and Minn. R. 7050.0224, subp. 2, due to the Agency’s failure to establish the reasonableness of the repeal, and because the repeal conflicts with the requirements 33 U.S.C. § 1313(c), 40 C.F.R. § 131.10(b) (2015) and Minn. R. 7050.0155 (2017) [Clean Water Act and its regulations].

DISAPPROVED restricting the list of wild rice waters. The MPCA could list 1300 wild rice waters only if other waters where wild rice has been an existing use since November 1975 were also protected.

DISAPPROVED changing the narrative standard that protects wild rice from harm due to changes in human-made conditions, such as flooding.

DESCRIBED concerns about preventing increased mercury methylation as well as further harm to wild rice and recognized the burdens that would be placed on Native American communities if the wild rice sulfate rule were changed.

Wild Rice Sulfate Rule Timeline


From 2011 through 2017, the Wild Rice Sulfate Standards Study Advisory Committee met at least once a month, and WaterLegacy attended every meeting and conference.

Feb. 2014

After the scientists had made their reports, the MPCA drafted Findings and Preliminary Recommendations that proposed preserving Minnesota’s wild rice sulfate standard as needed and reasonable. Excerpts of MPCA’s Findings and Recommendations are quoted below:

Sulfide is toxic to wild rice. The MPCA Study demonstrated that elevated sulfide concentrations were toxic to wild rice seedlings. Hydroponic experiment data showed deleterious effects of sulfide on seedling plant growth when sulfide exceeded the range of 150 to 300 µg/L.

Sulfide in the sediment is affected by the amount of sulfate in the water column, and the amount of iron in the sediment.

The 10 mg/L sulfate standard is needed and reasonable to protect wild rice production from sulfate‐ driven sulfide toxicity. The MPCA will also consider including a sediment sulfide concentration as a component of this water quality standard, in the range of 150 to 300 µg/L sulfide.

The 10 mg/L wild rice sulfate standard should continue to apply to both lakes and streams.

MPCA internal emails reveal that MPCA presented these findings and recommendations to a group of Iron Range legislators prior to their planned release. The day before the findings were set for release to the public, the Governor’s staff wrote, “This is a big deal and it is blowing up this morning.” MPCA’s Commissioner agreed, “the meeting with range legislators went poorly.” According to MPCA staff, the “plug got pulled” on support of the existing standard. After February 2014, MPCA no longer supported Minnesota’s existing rule limiting sulfate in wild rice waters to 10 mg/L.

June 2014

MPCA first proposed an equation that would allow more sulfate pollution in waters that had high levels of iron in their sediment. MPCA also proposed to set arbitrary acreage and “density” limits on the wild rice waters that would be protected from sulfate pollution. WaterLegacy opposed MPCA’s proposal and MPCA’s efforts to bias peer review. The documents below include MPCA initial rule proposal and WaterLegacy’s responses:
Dots show wild rice waters. Blue and green areas have less than 10 mg/L sulfate – within the range of the existing standard. Yellow-orange, orange, and red areas, respectively, have above 30 mg/L, 100 mg/L and 250 mg/L of sulfate. (MPCA map)


WaterLegacy, tribes, wild rice task force participants, and experts challenged MPCA’s proposed changes to weaken wild rice sulfate standard.


WaterLegacy continued to submit legal and scientific analysis opposing MPCA proposed rule amendment as ineffective to protect wild rice and improper under the Clean Water Act.


MPCA’s proposed rule did not resolve the concerns raised by WaterLegacy, tribes, and independent scientists. WaterLegacy submitted a total of 2,406 citizen petitions, letters, and postcards opposing the MPCA’s proposal to eliminate the 10 mg/L wild rice sulfate standard and arbitrarily restrict wild rice waters.

WaterLegacy also testified and submitted 1400 pages of comments, exhibits, and expert opinions opposing MPCA’s proposed rule as unreasonable, arbitrary, inconsistent with science, unprotective of wild rice, and in violation of the Clean Water Act. 


The Administrative Law Judge rejected MPCA’s proposed rule to repeal the wild rice waters.
The Timberjay reported:
“This is a really strong victory for clean water and the rule of law,” said attorney Paula Maccabee of Duluth-based Water Legacy, who had submitted over 1,400 pages of expert testimony and comments in the case, some of which proved critical to the judge’s decision. Water Legacy’s Maccabee said that’s the best part about the latest decision. “The existing standard is a whole lot more protective of wild rice in the case of mining pollution than what the MPCA would have given to them [the industry],” she said.
Photo by Eli Sagor.
“If the Legislature decides to get rid of the [existing] standard, we now have a detailed hearing record and an 82-page decision saying that the standard is needed to protect wild rice,” she said. “We’d have a pretty decent record to challenge such an action by the Legislature. What this careful and rigorous opinion says above all is that the law matters.”
The Star Tribune reported:
“It has been a long and difficult road,” said Paula Maccabee, head of Water Legacy, an environmental group that has fought the proposed rule since the beginning. “For the first time in a long time, it feels as if the rule of law matters.”