The city of Maple Valley has posted caution signs on Lake Wilderness due to a cyanobacteria (blue-green algae) bloom.

The cyanobacteria is producing microcystin toxins that may threaten the health of people and pets if contacted or ingested.

Cyanobacteria are carried around on the water surface by the wind where it can accumulate at the shoreline forming a ribbon or band of scum.

Contact with any visible scum should be avoided.

Young children and dogs are particularly at risk. Young children playing at the shoreline may contact the scum or get it in their mouths and dogs may drink it or lick it off their coats.

Common symptoms include nausea, vomiting, diarrhea and eye or skin irritation.

If water with visible scum is contacted or ingested, notify your doctor or veterinary and follow their instructions.