Lake Simtustus, northwest of Madras, is shown in this fie photo. 

A health advisory for Lake Billy Chinook and Lake Simtustus, issued earlier this month, has been lifted.

The advisory was in place for over two weeks due to suspected high levels of cyanotoxins in the reservoirs. Water monitoring has confirmed that cyanotoxin levels are below recreational guidelines for people and dogs, the Oregon Health Authority said in a news release.

Satellite monitoring also confirms a decrease in algal-bloom intensity, which is attributed to cooler weather.

The health authority advises the public to be alert to signs of cyanobacteria blooms in both reservoirs as blooms can return under certain conditions.

People with small children and pets should avoid areas where water is foamy, scummy, thick like paint, pea-green or blue-green, or if thick brownish-red mats are visible, or if bright green clumps are suspended in the water. If any of these signs are visible, avoid activities that could result in swallowing water or inhaling droplets, such as swimming or high-speed water activities.

Cyanotoxins can also exist in clear water. When a bloom dies, toxins released may reach into clear water around the bloom. Some species of cyanotoxins can also grow on aquatic plants and release toxins into clear water.

To report an illness, contact OHA at 971-673-0482. More information on cyanobacteria blooms can be found on the Oregon Health Authority website.