A harmful cyanobacterial bloom (HCB) recreational use Toxin Advisory has been issued for Lake McKenzie: Dog Park Shore, Wind River: Upper Wind River Campground, Ocean Lake: Long Point Ramp, Boysen Reservoir: Brannon Campground and Boysen Reservoir: Tamarask Campground. The Wyoming Department of Health (WDH) works cooperatively with the Wyoming Department of Environmental Quality to issue recreational use advisories when cyanobacterial cell densities or cyanotoxin concentrations pose a risk to people engaging in swimming or similar water contact activities in areas where cyanobacterial blooms occur. HCBs may also pose a health risk to animals. The WDH is working directly with resource management agencies to ensure signs are posted at the reservoir. Additional details regarding advisories and other HCB resources can be found at WyoHCBs.org.
Bloom advisories are issued when a HCB is present and cyanotoxins may be present. Toxin advisories are issued when cyanotoxins exceed recreational thresholds. 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.
If you encounter a potential HCB, the Wyoming Department of Health and the Wyoming Livestock Board recommend the following:
- Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scums.
- 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 and contact a doctor or veterinarian.
Current HCB Recreational Use Advisories*
| Waterbody Name | Observation or Sampling Location(s) | Advisory Type | Date Issued |
| Boysen Reservoir | Brannon Boat Ramp, Marina Campground, Sand Mesa Campground | Toxin | 07/19/2024 |
| Boysen Reservoir | Brannon Campground, Tamarask Campground | Toxin | 08/15/2024 |
| Brooks Lake | Middle of Lake | Bloom | 08/06/2024 |
| Diamond Lake (Bosler Reservoir) | Northwest Access | Bloom | 07/26/2024 |
| Fontenelle Reservoir | Fontenelle Creek Campground | Bloom | 08/06/2024 |
| High Savery Reservoir | Dam, Boat Ramp, South Shore | Bloom | 07/03/2024 |
| Lake McKenzie | Dog Park Shore | Toxin | 08/15/2024 |
| Leazenby Lake | South Access | Toxin | 07/22/2024 |
| Meeboer Lake | Boat Ramp | Bloom | 08/06/2024 |
| Miller Lake | Dam | Bloom | 07/10/2024 |
| Ocean Lake | Long Point Ramp | Toxin | 08/15/2024 |
| Rainbow Lake | Shore | Bloom | 07/26/2024 |
| Saratoga Lake | East Shore | Bloom | 07/19/2024 |
| Seminoe Reservoir | North Red Hills Ramp | Toxin | 07/23/2024 |
| West Granite Springs Reservoir | West Causeway | Bloom | 08/13/2024 |
| Wheatland Reservoir #1 | East Shore | Bloom | 07/18/2024 |
| Wheatland Reservoir #3 | Northwest Boat Ramp | Bloom | 07/17/2024 |
| Woodruff Narrows | North Boat Ramp | Bloom | 07/19/2024 |
| Wind River | Upper Wind River Campground | Toxin | 08/15/2024 |
Questions about health effects and recreational use advisories can be directed to Courtney Tillman, Surveillance Epidemiologist, Wyoming Department of Health, at courtney.tillman@wyo.gov or (307) 777-5522. Questions regarding cyanobacteria sampling can be directed to Chloe Schaub, Natural Resource Analyst, Wyoming Department of Environmental Quality, at chloe.schaub@wyo.gov or (307) 777-2073.