This stuff comes back to Illinois year after year when the weather starts to get warm and stay warm, and it's definitely something to keep your pets away from at all times.
If you recall, back in 2019, The Illinois Environmental Protection Agency (IEPA) and the Illinois Department of Public Health (IDPH) were asking Illinois residents to be more vigilant about where they boat, ski, and swim over the summer due to blue-green algae "blooms" that are occurring in Illinois' lakes and rivers.