Answers to questions surrounding a mysterious glittery film found floating in Lake Michigan on Monday may not come for another two weeks or more.
Representatives from the Indiana Department of Environmental Management initially expected lab results on the substance to be returned within a few days or a week.
But Dan Goldblatt, spokesman for the Indiana Department of Environmental Management, said Friday the results could take two weeks or more. The July 4 holiday could extend the wait even longer, Goldblatt said.
Swimmers discovered the substance floating atop Lake Michigan waters near Porter Beach Monday afternoon when they emerged covered in the dark, sticky, glittery film.
IDEM and the U.S. Coast Guard said the plume was 2 miles long and half a mile wide, but quickly disappeared. It was unclear whether the material dissipated or sank to the bottom of the lake.
IDEM earlier this week reported preliminary test results showed the substance to contain tricalcium orthophosphate, an anti-caking agent used as a food additive and in industrial applications. A Porter plant manufactures the material and ships it out on barges from the Port of Indiana. The plant has not been cited as a source, IDEM officials said.
U.S. Coast Guard investigators examined two weeks of logs at the Port earlier in the week and ruled out vessels there, as well as nearby ArcelorMittal, as the source of the material.
The investigation prompted swimming advisories and beach closures at the Indiana Dunes National Lakeshore and Indiana Dunes State Park. Beaches reopened Wednesday after IDEM and the U.S. Geologic Survey determined there was no health risk associated with swimming in the waters.