LAKE GENEVA, Wis. (CBS 58) – Heat could be to blame for potentially harmful blue-green algae spotted in Geneva Lake.

The Walworth County Health Department says rising lake temperatures can lead to blooms. The blooms can pose health hazards to animals and humans.

There have been no reports of anyone getting sick but the Geneva Lake Environmental Association has posted signs to "swim at your own risk." 

Those with symptoms are told to call their doctor. For a full list of symptoms and how to report exposure, please click here. 

The discovery could impact Saturday's Escape Triathalon. The Health Department and race organizers will make the call if its safe to swim in the morning and will notify participants.