Blue Green Algae or pond scum, which gets its name from its blue-green color, can produce many harmful toxins. Blue Green Algae form in shallow, warm, stagnate water and are made up of cells that bloom in water and then rise to the surface. These blooms can seem to appear overnight although in reality they have been forming underwater and then just rise to the top.

Drinking water containing blue green algae can be harmful to your health. Drinking water affected with these algae can cause headaches, fever, diarrhea, vomiting and abdominal pain. Exposure to this water through swimming may cause itchy skin, irritated eyes and other hay fever like symptoms. Although this exposure is unlikely to cause death your best bet is to avoid water with blue green algae.

Avoiding exposure is easy as long as you avoid water with signs of blue green algae growth or just avoiding shallow water that is warm and stagnate. Children and pets are more susceptible to blue green algae toxins and their exposure could lead to serious health problems, which may include death. People normally in general will avoid this type of water just based on smell and sight but you should make sure to watch your pets and children carefully.