HDBs at Ocean Lake 2023

By Kimberly Mazza

The Wyoming Department of Environmental Quality (DEQ) continues to investigate, monitor, and report on harmful cyanobacterial booms (HCBs) in Wyoming waters. Though HCBs have been present in waterways throughout the country for many years, Wyoming has been proactive to understand where and why HCBs are occurring. Wyoming’s HCB program, outlined in an Action Plan, describes Wyoming’s process to inform collaborators and the public when HCBs are present so they can make informed decisions to protect public and animal health. 

Together with the Wyoming Department of Health, Wyoming Livestock Board, and local, state, and federal partners, the DEQ wants to remind people, including hunters and fisherman, to continue to avoid and keep animals away from harmful cyanobacterial blooms that may be present.

Wyoming’s HCB webmap can be used to find where blooms are located, types and densities of cyanobacteria present, and toxicity levels of sampled blooms. To report a suspected bloom, bloom-related illness, or find additional HCB-related information, go to

If you encounter a confirmed or potential HCB, the Wyoming Department of Health and the Wyoming Livestock Board recommend the following:

  • Avoid contact with water in the vicinity of blooms, especially in areas where cyanobacteria are dense and form scums.
  • Do not ingest water from a 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 a bloom.
  • Do not allow pets or livestock to drink water near a 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 and contact a doctor or veterinarian.

Questions about health effects and recreational use advisories can be directed to Courtney Tillman, Surveillance Epidemiologist, Wyoming Department of Health, at or 307-777-5522.

Questions regarding HCB sampling can be directed to Kelsee Hurshman, Natural Resource Analyst, Wyoming Department of Environmental Quality, at

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