INDIANA (AP): State officials say they’ll continue testing waterways for blue-green algae ahead of the Labor Day weekend.

Blue-green algae growth, known as cyanobacteria, is made up of microscopic organisms that naturally occur in streams and lakes. Much of it is harmless, but some can produce toxic chemicals that cause sickness in people and pets. If there’s contact, health officials recommend rinsing off with fresh clean water quickly.

The Indiana Department of Natural Resources is posting testing updates online. Officials started testing waterways around Memorial Day and will finish before Labor Day.

High counts have been detected in several lakes, including Worster Lake at Potato Creek State Park.

The South Bend Tribune reports that on a recent day, visitors, including Warsaw resident Jason Chilafoe who was with his children and dogs, avoided the water.