BOISE, ID – With summer temperatures rising and outdoor recreation in full swing, Idaho health officials are warning the public to be on alert for harmful algal blooms, which can pose significant health risks to both humans and animals.
The Idaho Department of Environmental Quality (DEQ) and Department of Health and Welfare (DHW) say now is the peak season for blooms of cyanobacteria—commonly known as blue-green algae—which may produce toxins in lakes, reservoirs, and other waterbodies. These harmful algal blooms (HABs) can lead to skin irritation, stomach pain, vomiting, and even more serious illnesses if contaminated water is swallowed.
Pets, livestock, and wildlife are particularly at risk, as they are more likely to swim in or drink from contaminated sources. Officials advise pet owners to immediately wash animals with fresh water and soap if exposure is suspected, and to contact a veterinarian if symptoms develop.
The blooms often appear as green or blue-green scum, foam, or mats on the water’s surface and may look like pea soup, spilled paint, or grass clippings. A strong or unpleasant odor is sometimes present as well.
Officials emphasize the importance of checking for health advisories before heading out to lakes or rivers. The Idaho DHW maintains a real-time Recreational Water Health Advisories Map, while DEQ provides up-to-date water quality data on its Cyanobacteria Harmful Algal Blooms webpage.
“If the water looks suspicious or smells bad, it’s best to stay out,” the DEQ said in a statement. “That includes keeping pets and livestock away, too.”
Health officials advise against drinking or cooking with affected water, as boiling or filtering will not remove the toxins and may actually increase health risks.
Residents can report a potential bloom online at deq.idaho.gov/report-a-harmful-algal-bloom, by emailing algae@deq.idaho.gov, or by calling (866) 671-5385.
Additional resources are available for those with questions:
More information can be found at the Idaho Department of Environmental Quality website.
