The Panhandle Health District is warning people about the water in Fernan Lake in North Idaho.
A health advisory is in effect for people and pets. The popular fishing spot just east of Coeur d'Alene is suffering from a blue green algae bloom that creates toxins in the water.
Doctor Bill Miller lives on Fernan Lake. He was the first person to notice unusually high levels of blue green algae he attributes to a combination of factors.
"There's other changes with the heavy rains we've had and things like that, the road construction that was done that left a lot of bare ground that hasn't gotten covered up yet. There's a lot of things and I don't think we can point fingers at all," Miller said.
Sun-loving blue green algae floats along the surface. Take the plunge just a few inches below the waves and the lake looks normal. But in high concentrations the algae creates cyanobacteria, enough toxin to make you sick.
"The main worry is drinking water.You don't want to get the water inside you. You don't want to ingest it. You don't want to inhale it when you're playing, Cynthia Taggart of Panhandle Health said.
The algae-generated toxins can also make fish risky to eat unless you remove all the skin and fat from your catch.
Two dogs that spent too much time on a beach where the wind had collected the algae reportedly died of liver failure.
A change in our weather could help put the algae growth back at their normal levels. The Department of Environmental Quality will also be working with nearby property owners to help reduce the amount of nutrients entering the lake.