Information for Harmful Cyanobacterial Blooms in Wyoming Waters

August 20, 2019

Information for Harmful Cyanobacterial Blooms in Wyoming Waters

The Wyoming Department of Environmental Quality (DEQ), the Wyoming Department of Health (WDH) and the Wyoming Livestock Board (WLB) are currently experiencing an increased number of inquiries regarding harmful cyanobacterial blooms (HCBs) in Wyoming waters.

HCBs typically occur in still or slow-moving water as temperatures increase during the summer. They are episodic and can last for a few hours or a number of months.

Cyanobacteria, also known as blue-green algae, can form blooms that produce toxins and other irritants that pose a risk to human, pet and livestock health. WDH issues a recreational use advisory for publicly accessible waterbodies once DEQ determines that harmful levels of cyanobacteria and/or toxins are present in the water.

DEQ, WDH and WLB are reminding the public to check on current recreational use advisories by visiting

Suspected HCBs can be reported to DEQ by calling the Report a Spill hotline at (307) 777-7501 or submitting a complaint online at At this time, DEQ is only able to investigate and sample waterbodies that are accessible to the public. Private landowners who need to test for HCBs are encouraged to review Wyoming’s HCB Action Plan for more information on simple tests and analytical services.

If an HCB is present, the WDH and WLB recommend the following:

  • Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scum.

  • Do not ingest water from the bloom. Boiling, filtration and/or other treatments will not remove toxins.

  • Rinse fish with clean water and eat only the fillet portion.

  • Avoid water spray from the bloom.

  • Do not allow pets or livestock to drink water near the bloom, eat bloom material or lick fur after contact.

  • If people, pets or livestock come into contact with a bloom, rinse off with clean water as soon as possible.

Seek medical attention or a veterinarian if a person or animal is experiencing adverse health effects after exposure to a cyanobacterial bloom. Young children, pregnant women, people with weak immune systems and animals are especially at risk. Questions regarding general health risks and symptoms related to a cyanobacterial bloom can be referred to Dr. Karl Musgrave, State Public Health Veterinarian and Environmental Health Epidemiologist with WDH at 307-777-5825. More health information is also available at

For additional information on HCBs in Wyoming and to sign up for advisory updates, please visit