The leak took place at the Burns Waterway near Portage, Indiana, on Tuesday, April 11, and was reported to authorities by U.S. Steel Midwest Plant in Portage.
Some beaches along Lake Michigan remained closed Wednesday after a chemical spill at a U.S. Steel facility in Portage, Ind.
U.S. Steel says a pipe failure apparently caused a spill that released an unknown amount of wastewater containing a potentially carcinogenic chemical into a lake tributary.
Although water intake sampling "initially" indicated levels of hexavalent chromium "slightly above the detection limit", EPA said, a later confirmation run on that same sample "showed that it was at or below the detection limit", that is, "well below EPA's health-based standard for drinking water".
In response, the National Park Service has closed four beaches in the area of the spill "as a precaution to protect the health of park visitors", warning that people and pets "should have no contact with the water of Lake Michigan".
Officials have yet to determine how much hexavalent chromium was released into the water.
"U. S. Steel now expects the controlled, phased and highly monitored restart to begin later today".
The plant has sat idle since Tuesday, when the company said an expansion joint failed in a pipe, allowing wastewater to flow into the wrong treatment plant at the Portage complex. The city conducted emergency water testing at its 68th Street water intake crib, according to the Tribune, and found no unusual changes.
Officials with the park and the U.S. Environmental Protection Agency have said the spill did not cause a fish kill, though park officials were going to continue to monitor any possible long-term effects on the park's natural resources.
Operations will be shut down immediately if elevated levels of chromium are detected, U.S. Steel said. The utility said Wednesday that preliminary water sampling by an independent laboratory under the oversight of the Environmental Protection Agency had found no hexavalent chromium in the water treated and stored by that plant.
"The Ogden Dunes facility will remain offline until such time as additional data and water testing results confirm there is no threat to the company's source water at this location", IAWC added. EPA does not have a separate hexavalent chromium standard.
The EPA says test results to see how far the chemical traveled in the lake should be released later today. Normal levels for hexavalent chromium in Lake Michigan range between 0.14 to 0.15 parts per billion, according to Chicago's Water Management Department.
There is concern that a chemical leak just yards from Lake Michigan could have a lasting impact in northwest Indiana.
The EPA and its partner agencies, including the National Park Service, reviewed U.S. Steel's operations restart plan, and the EPA will observe the startup process and closely monitor the outfall discharge.