Butte, Mont. – July 27, 2021 – Harmful algae blooms (HAB) are present on Hebgen Reservoir in the northeast portion, in the Grayling Arm area, of the reservoir. Routine monitoring of Hebgen has confirmed the presence of toxins, anatoxin-a and microcystin, that pose a risk to people, pets and livestock.
Ingestion or prolonged contact with the algal bloom may result in illness, with signs such as muscle twitching, staggering, convulsions, paralysis and death. Importantly, children and pets are more likely to ingest HAB infested waters because they spend most of their time wading in the shallow waters where algae can accumulate, and they have less control over how much water they ingest. Animals and livestock that drink large amounts of contaminated water, and pets that collect scum on their fur and then ingest it by licking, are at high risk of toxin exposure. Toxin exposure can occur in humans from recreational activities where water might be ingested such as swimming, wind surfing, jet skiing, and water skiing.
Health experts recommend people not swim or take part in activities likely to result in exposure to the toxin in areas where the algal bloom is present. Additionally, pets and livestock should be prevented from entering the water in that area.