SAULT STE. MARIE (AP) — A freighter in Lake Superior hit something underwater Saturday and began taking on water, according to the U.S. Coast Guard.

The Coast Guard Great Lakes district received reports about 6:53 a.m. that a 689-foot-long ship called the Michipicoten had collided with something about 35 miles southwest of Isle Royale. The ship was carrying taconite, a low-grade iron ore, and had 22 people aboard.

Water pumps onboard began displacing water, authorities said, and there were no signs anything spilled from the ship. By 9:15 a.m., water pumps had reduced the listing of the freighter from 15 degrees to 5 degrees, the Coast Guard said.

Helicopter and boat crews responded, the Coast Guard said.

About 12:30 p.m. the Coast Guard said half of the people on board had been evacuated from the vessel for safety. The ship was on its way to a port for inspection and repairs.

Authorities say the cause of the collision will be investigated.

The collision occurred in the northwest part of the lake, which straddles the U.S.-Canadian border.