WINTER HAVEN, Fla. (WFLA) — Health officials are urging Polk County residents and visitors to be careful in and around a lake located west of Haines City.

The Department of Health issued a health alert due to harmful blue-green algae that was found in Lake Henry on Oct. 13.

People are advised to avoid swimming or boating in the lake where an algal bloom is visible. They should also keep pets away and avoid eating shellfish from the lake – but eating fillets from healthy fish is OK. Do not cook or clean dishes with contaminated water. Boiling the water will not get rid of the harmful toxins.

The health department said blue-green algae blooms in warm, still water on sunny days, most commonly in summer and fall. Many types of this algae produce harmful toxins affecting humans, pets and wildlife.

To report symptoms from exposure to a harmful algal bloom, call the Florida Poison Information Center at 1-800-222-1222 to speak to a poison specialist.