PORTLAND, Ore.—Oregon Health Authority (OHA) has lifted the recreational use health advisory issued for all of Upper Klamath Lake in Klamath County. OHA issued the first advisory for Shoalwater Bay on July 30, expanded the advisory to include Howard’s Bay on Aug 30 and expanded the advisory to cover all of Upper Klamath Lake on Sept 10.

Water monitoring has confirmed that the level of cyanotoxins in recreational areas sampled on Upper Klamath Lake are below recreational guideline values for people. However, OHA recommends that people keep a close eye on their pets when frequenting the lake and keep them out of areas that look suspicious.

OHA advises recreational visitors to continually be alert to signs of cyanobacteria blooms. This is because blooms can develop and disappear on any water body at any time when bloom conditions are favorable. Be aware that only a fraction of waterbodies in Oregon are monitored for blooms and toxins, so it’s important for you to become familiar with signs of a bloom, exposures and symptoms by visiting OHA’s Cyanobacteria Harmful Algae Bloom website at http://www.healthoregon.org/hab


When recreating, people and especially small children and pets should avoid areas where the water is foamy, scummy, thick like paint, pea-green or blue-green, or if thick brownish-red mats are visible or bright green clumps are suspended in the water. If you see these signs avoid activities that cause you to swallow water or inhale droplets, such as swimming or high-speed water activities, and keep your pets out of the area.

Cyanotoxins can still exist in clear water. When a bloom dies toxins released may reach into clear water around the bloom. Blooms can be pushed into other areas, leaving behind the toxins released. There also are species of cyanobacteria that anchor themselves at the bottom of a water body, live in the sediment, or can grow on aquatic plants and release toxins into clear water.

For health information or to report an illness, contact OHA at 971-673-0482.