Tools for Local Government Agencies: 
Harmful Algal Bloom-Related Illness

When local authorities such as county or city officials are aware of a blue-green algae bloom or a waterbody with chronic blue-green algae occurrence, they may choose to post an advisory sign or recommend the lake or beach be closed to in order to protect public health.

These signs are templates designed to assist local authorities with lake or beach advisories and closures due to blue-green algae. 
The posting and removal of all signs is at the discretion of the local agency.

• Water Advisory (PowerPoint)
  This sign advises visitors that the water may contain blue-green algae and provides ways to reduce the risk of illness.
• Water Warning (PowerPoint)
  This sign warns visitors that the water contains a blue-green algal bloom and contact with the water is not advised. Recommendations about boating and fishing are also provided.

MPCA: Blue-Green Algae and Harmful Algal Blooms
More information about what blue-green algae blooms look like from the Minnesota Pollution Control Agency.