(ABC 6 News) — Federal regulators are considering taking action after a coal ash spill in northern Minnesota.

The EPA issued what’s called a “notice of federal intent” into last month’s spill in Cohasset. More than five million gallons of contaminated wastewater spilled at the Boswell Energy Center.

Records obtained by our sister station KSTP from April show the state warned Minnesota power about a series of smaller spills and gave them 30 days to take measures to prevent another one.

Months later, the big spill happened.

“The items listed in that letter, we are working on those, but … they would not have done anything to prevent this spill,” said MN Power Director of Environment Kurt Anderson.

There is growing concern among those who swim, fish, and harvest rice near that plant.