WEST YELLOWSTONE — State officials have confirmed the presence of a harmful algal bloom (HAB) in the Rainbow Point Campground area of Hebgen Reservoir, prompting an advisory for people to avoid contact with the water.
Routine monitoring detected anatoxin-a, a HAB toxin that can pose serious health risks to humans, pets and livestock, according to Madison County Emergency Management and NorthWestern Energy. Exposure can occur by swallowing or prolonged skin contact with HAB infested water and may cause symptoms such as muscle twitching, staggering, convulsions, paralysis and even death.
Children and pets are considered at higher risk because they tend to wade in shallow areas where algae accumulates and have less control over water ingestion. Animals and livestock are also at risk if they drink contaminated water or, in the case of pets, lick algae from their fur.
HAB often appear as pea soup, grass clippings or paint-like scum in the water. Officials have posted warning signs at public access points in the affected campground area. No other sections of the reservoir have been reported to have blooms at this time.
NorthWestern Energy is monitoring the situation and will provide updates if conditions worsen or additional restrictions are needed.
Authorities remind the public: “When in doubt, stay out.” Anyone suspecting a harmful algal bloom-related illness should call Poison Control at 1-800-222-1222 and seek medical attention.
Suspected blooms can be reported online at hab.mt.gov or by calling 1-888-849-2938.
