FLINT, Mich. (AP) — Authorities are responding to a significant oil spill in the Flint River in Flint.

Michigan’s environmental agency says the spill could be five miles long. Mayor Sheldon Neeley said state and local agencies were at the scene.

Booms are in place to contain the oil and the source of the spill is under investigation.

Officials say drinking water is not affected. Flint used the river for drinking water in 2014-15 before lead contamination caused the city to return to a regional water supplier.