A fresh round of toxic algae has triggered a recreational-use health advisory for the Upper Klamath National Wildlife Refuge, with Oregon Health Authority warning Thursday that cyanotoxin levels have climbed above the state's recreational guideline values. The alert covers wetlands in Klamath County and urges people to avoid swallowing water and to stay out of spots where the surface turns scummy, pea-green or blue-green. Officials are putting extra emphasis on children and pets, who are more vulnerable to the toxins.
What OHA Is Warning
According to the Oregon Health Authority, lab results detected microcystin at concentrations above recreational-use guideline values, which prompted the advisory. The agency is telling people to skip swimming and high-speed activities such as water skiing or power boating anywhere blooms or surface scum are visible, since spray from fast-moving boats can increase the odds of inhaling toxins. OHA is also recommending that people hold off on eating fish caught from affected areas until there is more information about how much toxin might be building up in fish tissue.
Children, Pets and Symptoms
The Oregon Department of Fish and Wildlife is spelling out the risk for dog owners, warning that dogs are particularly vulnerable and can become very ill or die after drinking or even just contacting contaminated water, a concern that also extends to hunters who handle birds or gear in affected areas, according to ODFW. People who are exposed to cyanotoxins may develop stomach cramps, nausea, vomiting and respiratory or neurological symptoms, and federal guidance advises rinsing off with clean water after any contact. If symptoms show up in people or animals, medical or veterinary care should be sought, per the U.S. Environmental Protection Agency.
Where This Fits Locally
Blooms and health advisories are nothing new in the Upper Klamath basin. Monitoring and local reporting have documented repeated advisories for Upper Klamath Lake and the refuge in 2025, and sampling has found toxin spikes in parts of the basin during past summers. Local trackers and reports note that conditions can flip from safe to hazardous quickly, depending on wind, temperature and nutrient levels, and area managers say advisories are updated as soon as new lab results come in. Community leaders and hunters have been urged not to use contaminated water when cleaning gear or handling harvested birds, and monitoring details are available from local trackers such as KBMP.
How To Stay Safe
Visitors are being advised to steer clear of water that looks foamy, thick or the color of wet paint, to keep pets leashed and away from the shoreline and to avoid eating fish from areas that are under advisory. Before heading out, people are encouraged to check the state's advisory map and OHA's Cyanobacteria (Harmful Algae) Blooms page for the latest updates and test results. If you or a pet are exposed and then develop symptoms, rinse off with clean water and contact your health care provider or veterinarian right away.
