Look out for harmful algal blooms when recreating this summer

How to identify a HAB:

A coloration or scum in the water that can look like spilled paint, pea soup, or grass clippings.

Often blue, green or red in color.

HABs can occur when certain water conditions (nutrient levels, sunlight and temperature) cause a rapid overgrowth of blue-green algae, also called cyanobacteria. Blue-green algae are native organisms and commonly occur at low, safe densities in Montana’s lakes, streams, and reservoirs. Blue-green algae are often confused with green algae since both can produce overgrowths (blooms) that can affect recreation, cause odor issues, and reduce oxygen in the water. However, green algae do not produce harmful toxins.

HABs can release harmful toxins in the water that may cause skin irritation, sicken humans and even kill pets or livestock if ingested. HABs do not always release toxins. Water sampling is the only way to determine if toxins are present.

When in doubt, stay out. Do not drink, swallow, or swim in water that shows signs of a HAB and keep kids, pets and livestock out. Direct contact, ingestion, or inhalation of the toxins may irritate the skin, eyes, nose, throat and respiratory system, or cause nausea, vomiting, diarrhea, headache, dizziness, muscle weakness or liver and kidney damage. If you suspect a HAB-related illness in a person or animal, call your health care provider or veterinarian immediately.

The Montana Department of Environmental Quality (DEQ) and Department of Public Health and Human Services (DPHHS) maintain a website where people can submit and view reports of suspected HABs at: HAB.mt.gov