Hebgen Reservoir closures expand as toxin levels rise at Corey Springs

GALLATIN COUNTY, Mont. — The Gallatin County Health Department (GCHD) announced on Friday that harmful algal blooms (HAB) have expanded in parts of Hebgen Reservoir and prompted a new closure at Corey Springs, after testing revealed increased toxin levels in the area.

The closure prohibits water-based activities at Corey Springs. Signs will reportedly be posted at public access points warning people that toxic algae has been found in the water.

Rainbow Point shoreline also remains closed due to high toxin levels found during regular sampling. GCHD officials noted that the Yellowstone Holiday area has shown improvement and has moved to a warning status.

"When in doubt, stay out! You can't tell for sure if an algal or cyanobacterial bloom is harmful just by looking at it," GCHD officials said.

The department urged people not to swim in water that smelled bad or looked discolored. It also warned that children and pets faced higher risk because they often spent more time in shallow water where algae is likely to build up in greater concentrations.

Blue-green algae are reportedly native to Montana freshwater lakes and reservoirs, but some types can create dangerous toxins. Health officials said that swallowing the water or having long contact with the bloom could lead to illness, including muscle twitching, staggering, convulsions, paralysis and death.

The department warned that people can be exposed during activities where water might be swallowed, including swimming, wind surfing, jet skiing and water skiing. Animals, livestock and pets also face high risk if they drink contaminated water or lick algae from their fur.

Blue-green algal blooms can look like pea soup, grass clippings or green latex paint. The algae may stay suspended in the water or form floating mats.

Anyone who suspects a HAB-related illness in a person or animal is urged to call Poison Control at 1-800-222-1222 and seek medical attention.

Members of the public can report a suspected bloom through the state HAB website or by calling 1-888-849-2938.