This story is part of our Quick Hits series. This series will bring you breaking news and short updates from throughout the state.
Harmful cyanobacteria bloom advisories have been issued for two more lakes in Wyoming.
Blooms were found in Glendo Reservoir and Goshen Hole Reservoir, and Brooks Lake.
This adds to the 10 waterbodies where advisories already exist this summer.
The state issues a bloom advisory for a water body when a cyanobacteria bloom is present and cyanotoxins may be present. A toxin advisory is issued for a particular location within a waterbody when toxin concentrations exceed safe recreational levels.
Waterbodies under an advisory are not closed, since HCBs may only be present in certain areas and conditions can change frequently. Advisories will remain in place until blooms have fully dissipated and cyanotoxin concentrations are below recreational use thresholds identified in Wyoming's HCB Action Plan.
Current HCB Recreational Use Advisories*
| Waterbody Name | Observation or Sampling Location(s) | Advisory Type | Date Issued |
| Boysen Reservoir | Brannon Ramp | Bloom | 6/23/2025 |
| Brooks Lake | Campground | Bloom | 7/24/2025 |
| Glendo Reservoir | Custer Cove Campground | Bloom | 7/23/2025 |
| Goshen Hole Reservoir | Northwest Campground | Bloom | 7/23/2025 |
| Grayrocks Reservoir | Southwest boat ramp | Bloom | 5/13/2025 |
| Little Soda Lake | Shore | Bloom | 5/12/2025 |
| Lower North Crow Reservoir | South Shore | Bloom | 6/10/2025 |
| Luckey Pond | Shore | Bloom | 7/18/2025 |
| Pathfinder Reservoir | Bishops Point Ramp | Bloom | 7/15/2025 |
| Viva Naughton Reservoir | East Ramp | Bloom | 7/1/2025 |
| Wheatland Reservoir #1 | East Shore | Bloom | 6/18/2025 |
| Wheatland Reservoir #3 | Northwest Ramp | Bloom | 7/17/2025 |
| Woodruff Narrows Reservoir | North Ramp | Bloom | 7/1/2025 |
*There may be additional waterbodies with HCBs that WDH and WDEQ are not aware of. Please report potential blooms to WDEQ and HCB-related illnesses to WDH.
As of mid-July, the state had not issued any toxin advisories.
Cyanobacteria, also called blue-green algae, can form blooms that produce cyanotoxins and other irritants that pose risks to human and animal health. The blooms may be green, tan, brown, or blue-green, and can float in or on the water. They often look like spilled paint, clumps, grass clippings, or scum. HCBs may also stick to underwater surfaces like rocks, plants, or debris, appearing as films, mats, or jelly-like balls.
If you, a pet or livestock touches the algae, rinse off with clean water as soon as possible. This water is not ok to drink, even if boiled or filtered. Seek medical attention if you or your furry friend gets sick after exposure.
The CDC lists symptoms of ingestion of cyanotoxins as headache, fever, bloody or dark urine, nausea, vomiting or diarrhea.
Young children, pregnant women, people with weakened immune systems and animals are at higher risk. More information on health risks and symptoms related to a cyanobacteria bloom can be found on the Wyoming Health Department’s webpage.
The Health Department and Wyoming Livestock Board recommend:
- Avoid contact with water in and around the bloom, especially in areas where cyanobacteria are dense.
- Do not swallow water from the bloom. Boiling, filtration, 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.
