LINCOLN, Neb. (AP) _ State health and environment officials have issued a health alert for toxic blue-green algae at Sutherland Reservoir in Lincoln County.

The alert was issued following tests of the reservoir water. Signs have been posted that urge people not to swim in the reservoir. People can still use the reservoir’s public areas for other activities.

Skin exposed to the toxin from certain strains of blue-green algae can develop rashes and blisters. Someone who drinks water containing the toxin is at risk for headaches, nausea and muscular pain.

Weekly water sampling has been conducted at 50 public lakes in Nebraska since the beginning of May.