(CNN) -- Cleanup and containment efforts are underway to contain an oil spill at BP's Whiting Refinery in Indiana.
A processing malfunction sent oil into a cooling system, then into a cove and finally into Lake Michigan.
BP said the problem was discovered at 4:30 p.m. Monday, March 24th.
State and federal officials are on the scene.
It's not known how much oil was spilled.
BP says the discharge has stopped and a north wind is helping move the oil to shore, helping with cleanup.