The Oregon Health Authority (OHA) has issued a public health advisory for Lake Billy Chinook after detecting cyanotoxin levels above the recreational safety threshold. The advisory follows the discovery of a harmful algal bloom in the reservoir’s waters, specifically in a tributary of the Deschutes River.
Cyanotoxins are hazardous substances produced by blue-green algae, also known as cyanobacteria. While these organisms occur naturally, excessive growth can lead to “algal blooms” that pose serious ecological and public health risks. The U.S. Environmental Protection Agency has noted the dangers of such blooms, which can impair water quality and threaten both wildlife and human health.
State authorities are urging the public to avoid swimming or engaging in high-speed water activities, such as water skiing or using motorized boats, in areas where the bloom is visible. The main risk comes from ingesting water containing the toxin. Although cyanotoxins are not absorbed through the skin, individuals with heightened skin sensitivity may experience rashes or irritation after contact.
Despite the advisory, health officials encourage visitors to enjoy alternative shoreline activities. Safe recreational options include fishing, hiking, camping, picnicking, bird watching, and low-speed boating such as canoeing or kayaking. Boating at slow speeds is considered safe as long as water spray is minimal, reducing the risk of inhaling aerosolized toxins.
Key Safety Guidelines and Risks
Water treatment is ineffective: Boiling, filtering, or using camp-style filtration systems will not remove cyanotoxins from contaminated water. Visitors should refrain from using untreated lake water for drinking or cooking.
Pet safety concerns: Dogs are especially vulnerable to cyanotoxins. They can become critically ill or even die within hours of exposure by drinking from the lake, licking contaminated fur, or consuming algal mats along the shoreline. Symptoms may include weakness, disorientation, seizures, lethargy, vomiting, and loss of appetite.
Human health symptoms: People who ingest or come into contact with the toxin may experience effects similar to food poisoning, including nausea, vomiting, and diarrhea. In more severe cases, symptoms can escalate to numbness, tingling, dizziness, and difficulty breathing.
Fish consumption advisory: Consuming fish caught in bloom-affected areas may pose unknown health risks. OHA recommends avoiding fish from these zones. If consumed, fish should be carefully cleaned — with skin, fat, and internal organs removed before cooking or freezing — as toxins are most likely to accumulate in those tissues. Fillets should be rinsed thoroughly in clean water.
Local campground managers can provide updated information on the safety of drinking water at nearby campsites and day-use areas. For further health guidance or to report illness linked to cyanotoxin exposure, contact the Oregon Health Authority at 971-673-0482 or visit their Harmful Algae Blooms information site.
Residents and tourists are urged to remain cautious and follow the state’s recommendations until water quality returns to safe levels.
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