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Recreational use advisory for Upper Klamath Lake updated November 4

November 4, 2020

The Oregon Health Authority updated a recreational use health advisory for Upper Klamath Lake today due to spread of the cyanobacteria bloom currently in place and cyanotoxins above recreational guideline values for human exposure. The lake is in Klamath County.

The advisory, originally issued Sept. 26 and updated Sept. 29, applied to Howard Bay and the surrounding area of Upper Klamath Lake. Due to the size of the lake and the unpredictability of cyanobacteria and the toxins produced, OHA updates advisories on the lake when new sampling data is received. Sampling showed toxin levels above recreational guideline values in several areas of the lake. In response to this new data, OHA is updating the advisory to include all of Upper Klamath Lake.

People should avoid swimming and high-speed water activities, such as water skiing or power boating, in areas of the lake where blooms are identified. Although toxins are not absorbed through the skin, people who have skin sensitivities may experience a puffy red rash.

People are encouraged to visit Upper Klamath Lake and enjoy activities such as fishing, camping, hiking, biking, picnicking, and bird watching. Boating is safe as long as speeds do not create excessive water spray, which could lead to inhalation risk.

Drinking water

Drinking water directly from areas of the lake affected by a bloom is especially dangerous. Toxins cannot be removed by boiling, filtering or treating water with camping-style filters. Contact campground management or the local health department with questions about water available at nearby campgrounds or day use areas.

People who are not on a well or a public water system and draw in-home water directly from an affected area are advised to use an alternative water source because not all private treatment systems are proven effective in removing cyanotoxins.

Children and pets

Children and pets are at increased risk for exposure because of their size and level of activity. People who bring their pets to a lake with areas affected by a bloom for recreation activities, regardless of whether a recreational use health advisory is in place, should take special precautions to keep them from drinking from or swimming in these areas. Dogs can also be exposed to cyanotoxins when present by licking their fur, licking cyanobacteria off rocks or eating cells from a bloom. The level of cyanotoxin in the Moore Park area, although not harmful to people, is still high enough to affect your pet.


Fish caught from areas where cyanobacterial blooms are present should have fat, skin and organs removed before cooking or freezing, as toxins are more likely to collect in these tissues. Fillets should also be rinsed with clean water.


Exposure to cyanotoxins can be serious and result in a range of symptoms, from those similar to food poisoning such as stomach cramping, diarrhea, nausea and vomiting, to more serious symptoms like numbness, tingling, dizziness and shortness of breath that may require medical attention.

For health information or to report an illness, contact the Oregon Health Authority (OHA) at 971-673-0482.

Learn more here

 Media contact

Delia Hernández

OHA External Relations


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