A health alert has been issued for Red Willow Reservoir near McCook.

The Nebraska Department of Health and Human Services and other agencies cited an excess of toxins from blue-green algae in the water.

An alert issued earlier this month for Holmes Lake in Lincoln remains in effect. The state plans to monitor 45 other lakes through September.

People can still camp, fish and boat on lakes under the alert, but should not have full-body contact.

The algae, which scientists say are plantlike bacteria, are common in freshwater. Some types can produce dangerous toxins.

Drinking toxin-tainted water can cause vomiting, diarrhea, respiratory failure and, rarely, death.