Cyanobacteria (also known as blue-green algae) are common native organisms in lakes, ponds and rivers around the world. In Vermont, they can be found in any water body, river or stream. Some species of cyanobacteria produce toxins and these toxins have been documented in some Vermont lakes. Cyanobacteria are not always toxic and it is not possible to tell by looking if toxins are present. For this reason, the Vermont Department of Health and the Vermont DEC recommend that everyone avoid contact with cyanobacteria.