MINNEAPOLIS (AP) _ Years of unchecked agricultural pollution has led Minnesotans to drink tap water contaminated with unsafe levels of nitrate, a chemical linked to different types of cancer and other serious health problems.

According to reports, an environmental group says Minnesota is on ``the brink of a public health crisis.'' As a result, Minnesota is implementing the Groundwater Protection Rule.

It prohibits applying commercial nitrogen fertilizer in drinking water supply management areas that already have elevated nitrate levels.

The rule also establishes an enforcement program encouraging farmers to adopt greener practices.