BISMARCK (AP) — North Dakota’s Health Department is warning residents to avoid blue-green algae that can develop in bodies of water.

Hot summer weather contributes to the production of the algae that’s also known as cyanobacteria. People and animals who ingest affected water can get sick and even die. There’s no known antidote for toxins blue-green algae can produce.

People are urged to avoid water that looks discolored or scummy or has a foul odor.

Algae blooms are most common in North Dakota in late summer, but it only takes a few hot days to cause the organisms to become active and bloom.

Not all algae blooms are toxic, and it’s impossible to identify poisonous species without laboratory analysis.