Cyanobacteria Harmful Algae Blooms

A harmful algal bloom (HAB) is an overgrowth of algae in a water body that could affect water quality and aquatic life. Some HABs produced by bacteria can create toxins that may also harm people and animals.

Algal blooms make the water appear green, brown, gold, or red. They often produce scum, mats, foam, or paint-like streaks in the water or clumps on the shore. However, only professional water testing can confirm if HABs and toxins are present.

A good rule of thumb to follow: when in doubt, stay out!

Oregon Harmful Algae Bloom Advisories

Only a fraction of all water bodies in Oregon are visually monitored or sampled due to limited physical and monetary resources. A water body with no recreational health advisory is not an indication that a bloom is not present. You are your own best advocate when ensuring your safety, and that of your family and pets.

If you believe you or your pet have been exposed to a CyanoHAB, OHA staff are available to answer health related questions and to receive and document illness reports

Washington state toxic algae

This database contains the most current toxicity data available. All instances of values above the recreational guidelines are kept as up to date as possible, but values below the guidelines may be somewhat delayed in entry.

Additional Resources