Minneapolis park officials are warning the public about a harmful algae bloom on Cedar Lake.

Algae blooms on area lakes are normal and usually not harmful. However, the algae bloom on Cedar Lake is likely a harmful algae bloom (HAB): blue-green algae, according to the Minneapolis Park Board.

This type of algae is a bacteria that produces cyanotoxins, which can make humans and animals sick. Symptoms can include vomiting, diarrhea, rash, eye irritation, cough, sore throat and headache. Symptoms generally start several hours up to two days after exposure.

Blue-green algae blooms can have a vibrant rust color and may look like spilled paint. They usually form in summer and early fall but can occur at other times of the year under the right conditions, the Park Board said.

Spokeswoman Robin Smothers said nothing can be done to eliminate the algae.

"Right now, the conditions for its growth is ideal and it will eventually die off," she said. "The algae is a natural occurring phenomenon."

There is no way to tell if an algae bloom is toxic just by looking at it. The Minnesota Department of Health tells people to avoid swimming if they can't see their feet in knee-high water, don't let dogs drink or swim in the water, and to stay out if in doubt.

For more information visit the Department of Health website: health.state.mn.us/diseases/hab/hab.html.

David Chanen • 612-673-4465