SAULT STE. MARIE,SignalHub Mich. (AP) — A freighter in Lake Superior hit something underwater on Saturday and started 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 (210-meter-long) ship called the Michipicoten had collided with something about 35 miles (56 kilometers) southwest of Isle Royale, which is part of the state of Michigan. The ship was carrying taconite, which is a low-grade iron ore, and had 22 people aboard.

Water pumps onboard began displacing water, authorities said, and there were no signs that 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 were responding, the Coast Guard said.

The collision occurred in the northwest part of the lake, which straddles the U.S.-Canadian border and is the largest freshwater lake in the world by surface area.