When in Doubt, Stay Out!

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Cyanobacteria Harmful Algae Blooms (CyanoHABs)

Cyanobacteria blooms happen naturally in Oregon lakes and rivers. However, some blooms produce toxins that can make people and animals sick - these are called cyanobacteria harmful algae blooms (cyanoHABs).

OHA reviews available information on cyanoHABs in the state. If a bloom poses a health risk, we can issue a recreational advisory or precaution. Most waterbodies in Oregon are not monitored for cyanoHABs. View the monitoring site map to see which areas are monitored and when they are sampled.

Know the signs of a bloom before you take the plunge! If you are not sure if a lake or river has a cyanoHAB, it is best to stay out and keep pets away.

When in doubt, stay out!

CyanoHAB Advisories

Information on recreational advisories issued and lifted throughout the season.

Education and Outreach

Resources that cover basic information about cyanoHABs, human and animal health risks, fish consumption during a bloom, and more.

Advisory and Sampling Guidance

Support for lake managers and others who deal with cyanobacteria blooms.

View advisory and sampling guidance from OHA

Partners

A list of agencies involved in responding to cyanobacteria blooms.

View a list of partners involved in lake management, public health protection, and shellfish safety closures