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!

Current Recreational CyanoHAB Advisories

The most current information on recreational advisories issued and lifted throughout the season.

Recreational CyanoHAB Advisory Archive

A record of recreational use health advisories issued in Oregon since 2007.

Browse the summaries and view the data for each year

Education and Outreach

Brochures, posters, fact sheets and journal articles that cover basic information, human and animal health, fish consumption and environmental concerns.

View the symptoms of human and animal cyanoHABs-related illness
Browse the list of FAQs
See our photo gallery for visual examples of cyanoHABs

View the Quick Guide to cyanoHABs (English brochure) (Spanish brochure)
View all resources

Advisory and Sampling Guidance
For lake managers and others who deal with cyanobacteria blooms.

View Advisory and Sampling Guidance

Partners

A list of agencies involved in responding to cyanobacteria blooms.

Activities include: lake management, public health protection, and shellfish safety closures