PORTAGE, Ind. (AP) — The National Park Service has reopened three beaches at Indiana Dunes National Lakeshore after tests showed no significant traces of a potentially carcinogenic chemical from a U.S. Steel Corp. wastewater spill.

The park service says water and beach sand samples taken last week came back below laboratory reporting limits for hexavalent chromium, so it reopened the beaches Monday afternoon.

The Environmental Protection Agency says U.S. Steel resumed full operations Monday at its Midwest Plant in Portage, about 30 miles east of Chicago.

The company began a gradual restart there Friday, three days after an expansion joint failed, allowing wastewater containing the chemical to flow into the wrong treatment plant at the Portage complex.

That wastewater eventually flowed into Burns Waterway at a point about 100 yards from Lake Michigan.