EFFINGHAM, N.H. — The New Hampshire Department of Environmental Services is warning about toxic blue-green algae on Province Lake in Effingham.

The algae blooms have been spotted near a boat launch and along the shore.

The department is telling lake users to avoid contact with the water in areas where there’s a surface scum or blue-green clouds.

It also recommends keeping pets out of that water.

The algae may form when excess phosphorus is in the water.

The toxins in some of the algae can cause skin irritation, nausea, vomiting and diarrhea. State environmental officials say more chronic effects include liver and central nervous system damage.