Exposure to any cyanobacteria HABs can cause health effects in people and animals when water with blooms is touched, swallowed, or when airborne droplets are inhaled. This is true regardless of toxin levels; some blue-green algae produce toxins, while others do not. Exposure to blooms and toxins can cause symptoms such as diarrhea, nausea or vomiting; skin, eye or throat irritation and allergic reactions or breathing difficulties.
 
Because blue-green algal bloom conditions change rapidly over time, the best prevention is to take steps to avoid waters with visible blooms: 

• People, pets, and livestock should avoid areas with blooms or surface scums, or water that is noticeably discolored. 
   
• Avoid blooms when swimming, boating, fishing, and don’t eat fish caught from areas of water with blooms.
   
• If you or your pets are exposed to blue-green algal blooms, stop using the water and rinse off with clean water.
   
• Consider medical attention for people and animals if symptoms such as diarrhea, nausea, or vomiting; skin, eye, or throat irritation; and allergic reactions or breathing difficulties occur after contact with surface waters with blooms.
   
• Never drink untreated surface water. Even if you treat it in your home with water filtration, chlorine, ultraviolet (UV) light, or other treatment; it’s still not protected from blue-green algae and toxins.