Good news for Jefferson County residents heading to Lake Billy Chinook this Fourth of July weekend: the Oregon Health Authority has downgraded the recreational health advisory for the lake, following recent water monitoring that showed cyanotoxin levels have fallen below recreational guideline values for humans.
The OHA had issued a full recreational use advisory for Lake Billy Chinook on June 12 after elevated levels of cyanotoxins — produced by blue-green algae — were detected in the water. As of June 30, those levels are low enough that general recreation for people is considered safe.
Dogs and Pets Still at Risk
However, the bloom has not disappeared. Toxin levels remain above the state's educational guideline values for dogs and other animals, and officials are urging pet owners to keep their animals away from any areas where algae blooms are visible.
Signs of a problematic bloom include water that appears:
- Foamy or scummy
- Thick like paint
- Pea-green or blue-green in color
- Containing thick brownish-red mats or bright green clumps
Cyanotoxins can remain present in water that looks clear, even after a visible bloom has dissipated, making visual inspection alone an unreliable safety guide.
What to Watch For
Blooms can develop and disappear quickly, and only a fraction of Oregon water bodies are routinely monitored by the state. Even with the advisory downgraded, conditions can change rapidly.
Visitors are advised to check for updated conditions before visiting the lake, especially over the busy holiday weekend.
For health information, to report a bloom, or to report an illness potentially related to algae exposure, contact the Oregon Health Authority at 971-673-0482 or visit OHA's Cyanobacteria webpage at oregon.gov/OHA.