An algal bloom has left Lone Lake unfit for swimming, said officials with the Island County Health Department.

There are now high levels of toxic algae in Lone Lake, Dr. Roger Case of the Island County Public Health Department said Monday.

The department is posting warning signs that the lake is unsafe for people and pets until further notice, Case said. He warned against swimming, water skiing or drinking lake water, and urged people to keep pets and livestock away.

Toxic blue-green algae, or toxic cyanobacteria, can produce microcystins which target the liver. Symptoms include nausea, vomiting and acute liver failure, Case said.

More information is available on the Washington State Department of Ecology’s Web site, www.doh.wa.gov/ehp/algae.