Skip to Content

Harmful algal blooms in Fremont County

FREMONT COUNTY, Idaho (KIFI) – Eastern Idaho Public Health and the Idaho Department of Environmental Quality (DEQ) issued a health advisory Thursday for Henrys Lake and the shoreline of Upper Island Park Reservoir in Fremont County due to the presence of harmful algal blooms (HABs).

Water samples confirmed the presence of the blue-green algae species Gloetrichia, Dolichospermum and Aphanizomenon—species with the potential to produce dangerous toxins. Precaution is advised.

Blue-green algae are microscopic bacteria that occur naturally in healthy water bodies. Under the right conditions, the physical appearance of blue-green algae blooms can be unsightly, often causing thick green mats along shorelines. They might also cause an unpleasant odor or stench. They occur in water conditions that are common during the warmer summer months.

People recreating at Henrys Lake and Upper Island Park Reservoir, near the dam up to Buttermilk boat ramp and Lakeside Lodge area are advised to avoid swallowing or inhaling water and to avoid direct contact with water containing visible algae. Drinking water from the lake is especially dangerous. The toxins cannot be removed by boiling or filtering the water. If people choose to eat fish from this area, they should remove all fat, skin, and organs before cooking since toxins are more likely to collect in those tissues.

Children and pets are particularly susceptible to the effects of blue-green algae. People exposed to blue-green algae might experience skin and eye irritation, nausea, diarrhea, numbness of hands and feet, and/or difficulty breathing. If symptoms occur, call your doctor. For animals, symptoms might include muscle spasms, decreased movement, labored breathing, convulsion, and death. If pets are experiencing these symptoms, call your veterinarian immediately.

The public will be advised when the concern no longer exists.

For questions about blue-green algae, please visit or contact Destiny Locke, Water Quality Analyst, at DEQ. She can be reached at 208-528-2650.

Breaking News / Idaho / Local News / News / Top Stories / Videos
Author Profile Photo

News Team


Leave a Reply

Skip to content