CHEBOYGAN -- The U.S. Coast Guard is cleaning up an oil spill in Cheboygan County.

Pollution investigators and marine inspectors from Coast Guard Sector Sault Ste. Marie are at the scene,  The main areas of concern are a beach at the Cheboygan State Park and a sheen in Duncan Bay.

A concerned resident contacted watchstanders at Station St. Ignace at about 3:20 p.m. Tuesday.

State park rangers have closed off affected areas of the beach during the cleanup effort.

The area of contaminated beach is estimated to be 25 by 300 yards. According to pollution investigators, the substance appears to be weathered/used heavy oil.

An aircrew from Coast Guard Air Station Traverse City, flew over the affected area Tuesday evening and Wednesday morning.

The sheen in Duncan Bay was reported to be about 5 by 300 yards.

Pollution investigators and marine inspectors have been on scene throughout the night, and are in the process of determining the pollution source.

There are two ships in the area, one anchored and one aground. Investigators plan to take samples from both vessels to determine if either is the source of the discharge.