After a toxic chemical spill near Lake Michigan in October, workers at a U.S. Steel plant did not test a tributary leading to the lake, despite seeing blue liquid "with visible solids," overflowing from a treatment tank, according to a government report.

The Oct. 25 spill happened at a U.S. Steel plant in Portage, Ind., near the Indiana Dunes National Lakeshore. A wastewater system malfunction led to the release of nearly 57 pounds of hexavalent chromium - almost double the amount of the cancer-causing compound that it is permitted to discharge in a 24-hour period.

According to a report this week by the Chicago Tribune, Indiana state regulators determined that following the spill, U.S. Steel did not test the Burns Waterway, which flows into Lake Michigan, for the chemical.

State inspectors responded with a recent report detailing the plant violations, saying: "Visual evidence of operational deficiencies, such as discolored effluent or solids leaving the facility ... should lead the facility to monitor for hexavalent chromium to determine the extent of the impact, even if the on-site personnel believe there will be none or little."