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Precautionary seasonal recreational use health advisory in effect for Lake Billy Chinook

Since cyanobacterial blooms can come and go throughout the season on Lake Billy Chinook, the following precautionary seasonal advisory has been issued

June 11, 2019

PORTLAND, Ore.—The Oregon Health Authority has issued a precautionary seasonal recreational use health advisory for Lake Billy Chinook due to cyanobacterial harmful algal blooms that routinely develop in the lake.

Lake Billy Chinook is located about 12 miles west of Madras, in Jefferson County. The advisory will remain in effect through Nov. 1, 2019.

Tests done at Lake Billy Chinook since 2015 show that blooms in the lake consistently produce cyanotoxins over OHA’s recreational use health guideline values for people and pets. In the past, OHA would issue and lift advisories on the lake as data were made available. Testing is costly, making it difficult for local water body managers to regularly test the lake during times when blooms occur. This makes it challenging to determine when cyanotoxins are being produced, and if an advisory is needed.

As a result, OHA and local partners determined that a 2019 seasonal advisory for the lake is appropriate. At this time, the OHA Public Health Division is reminding the public of the steps to take to reduce exposure to cyanobacterial blooms and the cyanotoxins that may be present throughout the season. OHA staff will evaluate the effectiveness of this advisory at the end of the 2019 season.

Enjoy non-water-related activities at Lake Billy Chinook

Non-water-related activities such as camping, hiking, biking, picnicking and bird-watching can be enjoyed with very little possibility of exposure to cyanotoxins. Certain water-related activities can be safe. These include canoeing, fishing and boating, if boating speeds are kept low to avoid kicking up spray that could be inhaled.

Activities to avoid in areas affected by cyanobacteria blooms

Avoid swimming, water-skiing, wake-boarding, tubing, and other high-speed water activities in areas of the lake affected by a cyanobacterial bloom. Watch children and pets to be sure they are not swallowing water or coming in contact with cyanobacterial blooms washed up on the shore or dried on rocks. Do not use lake water for drinking as camping-style filters and boiling do not remove the toxins.

What to look for

Cyanobacterial blooms are not unique to Lake Billy Chinook. Oregon health officials advise recreational visitors to always be alert to signs of cyanobacterial blooms in all Oregon waters because only a fraction of the many lakes and waterways in Oregon are tested by state, federal and local agencies.

Certain water body conditions can help people identify when a bloom may be present. People and their pets should avoid areas where the water is foamy, scummy, thick like paint, pea-green, blue-green or brownish red in color, a thick mat is present, or when bright green cells can be seen suspended in the water column, making the water a brighter shade of green. In areas where blooms are found, people should avoid swallowing water while swimming or inhaling water droplets made during high-speed water activities, such as water-skiing or power-boating. A good rule of thumb when encountering something in the water that doesn’t look familiar: “When in doubt, stay out.”


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. Although toxins are not absorbed through the skin, people who have skin sensitivities may experience a puffy, red rash at the affected area. Children are most vulnerable to exposure and illness due to their size and level of activity. If you or someone in your family develops any of these symptoms after your visit to an Oregon lake or waterway, contact OHA at 971-673-0440 for health information or to report the illness.

Pets are at risk, too

Over the past several years OHA has received many reports of dog illnesses and even deaths due to exposure to bloom-affected water. It’s important to know that dogs are susceptible to cyanotoxins at extremely low levels. Exposure to these toxins can also occur when dogs lick cyanobacteria off rocks and off their fur, eat the scum, or drink affected water. Symptoms of exposure are drooling, twitching, inability to stand or walk, convulsions and paralysis. Symptoms develop within the first hour or two after exposure and can be deadly. If a pet develops any symptoms, it should be seen by a veterinarian as soon as possible. OHA also takes pet illness reports; call 971-673-0440 for more information.

Other concerns

Drinking water directly from areas of Lake Billy Chinook affected by a cyanobacterial bloom is especially dangerous when toxins are present. 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.

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.

OHA maintains an updated list of all health advisories on its website that is also available by phone. OHA will update information for Lake Billy Chinook when new data are available. To learn what water bodies are being sampled for the season and whether an advisory has been issued or lifted, visit the Cyanobacteria Blooms website: and select “current cyanobacteria advisories,” or call the Oregon Public Health Division toll-free information line at 877-290-6767.

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 Media contact

Jonathan Modie

OHA External Relations


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