Chicago's water remains safe to drink after a chemical spill in a tributary of Lake Michigan, Mayor Rahm Emanuel said Thursday. The supply of water from the Borman Park facility is adequate to meet the needs of the company's customers in Northwest Indiana, he said. That facility has been taken temporarily off line.
Outfall results still show detectable hexavalent chromium in the waterway.
Overnight levels from Tuesday to Wednesday at the outfall were as high as 2,231 parts per billion, according to the EPA.
That's "a level higher than would be expected to be found in raw lake water", the department said in a news release, but it's just a fraction of the Environmental Protection Agency's drinking water standard of 100 parts per billion for all forms of chromium.
"The National Park Service is working with the EPA and other agencies to develop a long-term monitoring protocol", the release said. The company settled with the US Department of Justice, the Michigan Department of Environmental Quality, and the states of IN and IL.
EPA was expecting this morning to release another update later today.
"The plant will be closed until additional data and water testing results confirm there is no threat to the company's source water at this location", it said.
The National Park Service has closed a third beach along the Indiana Dunes National Lakeshore following a nearby toxic wastewater spill. Park officials Wednesday closed the beach at Cowles Bog, though the trails there remain open. That wastewater eventually flowed into Burns Waterway at a point about 100 yards from Lake Michigan. Steel plant in northern Indiana. That wastewater is supposed to flow into a special treatment plant, but the pipe failure prevented that from happening.
USS has not yet determined how much of the rinse water was actually discharged.
Indiana American Water idled its Ogden Dunes water treatment plant after being notified of Tuesday's wastewater spill at U.S. Steel's nearby plant in Portage, Indiana.
"The fact that these unsafe chemicals have not reached Chicago's water supply is simply due to good luck, and not good actions by U.S. Steel".
Those steps included "the isolation and fix of the damaged pipe, recovery of material, and the addition of a water treatment compound, sodium trithiocarbonate, to the wastewater treatment plant to convert and aid in the removal of hexavalent chromium". Hexavalent chromium is a toxic chemical, made famous in the movie Erin Brockovich, that is used to keep steel from rusting and has been linked to stomach cancer.
Among other things, compounds of the chemical are used to "electroplate chromium onto metal parts to provide a decorative or protective coating", OSHA noted.