HAUSER - Toxic blue-green algae has been identified in water samples along Hauser Lake's shorelines, prompting environmental agencies to issue a public health advisory.

The Panhandle Heath District and the Idaho Department of Environmental Quality advises against swallowing, inhaling or coming in contact with areas where algae is visible.

"If you see it, avoid it," said Bob Steed, IDEQ surface water ecologist. "We're taking action because, with this being a nice week, people will be more likely to be on the lake and getting near it."

Blue-green algae are naturally occurring, microscopic bacteria that can produce toxins harmful to humans and animals. Blooms have killed animals after exposure in some Washington lakes.

The physical appearance of blue-green algae blooms can be unsightly, often floating to the surface causing thick green mats several inches thick along shorelines. They often look like green paint floating on the water.

Samples were taken from the public beach on the south side of Hauser. Algae may be spotted in one area of the lake one day, then move to a different location or not visible at all the next day, depending on weather conditions, Steed said.

The public will be advised when the concern no longer exists.

The boat launch and beach are not being closed, but the public is being warned with signs and other notices, Steed said. Fishing and boating are still permitted.

"If the lake was half involved, that would be a real sign of an unhealthy lake, but we're not seeing that," Steed said.

Drinking water from the lake is especially dangerous, and children and pets are particularly susceptible. The toxins cannot be removed by boiling or filtering the water.

Algae blooms happen mostly in the summer or fall, but can occur anytime.

The recent warm weather is favorable for blooms in this region, and cool weather naturally takes care of it.

Hauser is the first North Idaho lake to have algae that has prompted a warning this year. Fernan is showing early signs that it may crop up, but it hasn't been in areas where people or animals frequent and hasn't required testing, Steed said. He also expects it may occur on Lake Cocollala if the weather persists.

The algae has already been reported in several lakes in eastern Washington, including Lake Spokane and Newman Lake.

Blooms occur in waters with high levels of nutrients like phosphorus and nitrogen.

Steed said a phosphorous reduction program on Hauser should limit the cases of algae in the future.