Oregon Health Authority has downgraded the recreational use advisory for Agency Lake in Klamath County from a health advisory to a precaution.
The agency issued the initial advisory on July 1 after detecting cyanotoxins in the water. Water monitoring confirmed that toxin levels are now below recreational guideline values for people, according to OHA.
However, the agency said levels are still above educational guideline values for dogs, and pet owners should keep their animals away from areas showing algae blooms.
Cyanobacteria blooms can appear and disappear quickly on any water body, OHA said, advising recreational visitors to watch for signs including foamy, scummy, thick, pea-green or blue-green water, or brownish-red mats and bright green clumps.
The agency cautioned that cyanotoxins can exist even in clear water after a bloom dies, as toxins can reach into surrounding areas or persist in sediment. OHA said only a fraction of Oregon's water bodies are monitored for blooms and toxins.