MINNEAPOLIS (WCCO) — A Robbinsdale lake is contaminated after a contractor accidentally released cement grout into a storm sewer Wednesday.

Crystal city officials say the accident happened during work on a water main project on County Road 9.

The contractor for the Joint Water Commission tried to contain the grout, but residents report that it flowed into Lower Twin Lake.

The JWC — which includes the cities of Crystal, Golden Valley and New Hope — says they are working with the Minnesota Pollution Control Agency to assess the scope of the spill and collaborate on a plan to remove the grout from the lake.