PLATTE COUNTY – The Wyoming Department of Environmental Quality (DEQ) has issued an expanded advisory following new water sampling that confirms the presence of toxic cyanobacteria blooms — including the vivid red variety some locals have dubbed “blood” — in several Platte County water bodies. Last week, the agency provided notification concerning cyanobacteria bloom, or HCB, in the Grayrocks, Wheatland No. 1 and Wheatland No. 2 reservoirs, and has now extended it to two other local watering holes. The July 22 bulletin builds on previous warnings and highlights new health concerns as microcystin toxin levels rise beyond safety thresholds.
The DEQ bulletin noted particularly high concentrations of Microcystis, a common type of harmful cyanobacteria known for producing microcystins, a group of toxins harmful to humans, pets, and livestock. Two additional water bodies in Platte County have now tested above the DEQ’s recreational use threshold of 8 micrograms per liter (µg/L), expanding the scope of the warning.
Among the affected areas is the blood-red-hued pond that gained local notoriety in early summer for its striking coloration and strong odor. There were community concerns when animals became sick after encountering the water, and early signs of fish kills were spotted.
Warnings extended, contact discouraged
“No Contact” advisories remain in effect, and officials stress that individuals and pets should avoid any interaction with affected water. Local authorities have posted signage around known bloom sites and are encouraging visitors to keep at least 10 feet from any scum or algae build-up along shorelines.
“These are not just nuisance algae blooms. They pose real health risks,” said a DEQ official in the release. “Touching or ingesting contaminated water — even accidentally — can lead to severe illness. Children and pets are especially vulnerable.”
If exposure does occur, health officials urge rinsing with clean water immediately and seeking medical or veterinary care if symptoms appear.
Expanded monitoring and community response
In response to the worsening bloom conditions, Platte County’s emergency services launched a phone alert system to keep residents updated on bloom activity and safety guidance. The DEQ has also committed to increased testing frequency throughout the hotter months, when blooms are more likely to form and intensify.
The advisory now includes additional reservoirs and smaller ponds within Platte County, and officials believe that other water bodies not yet tested could be at risk as temperatures remain high and nutrient levels in water increase — conditions that fuel cyanobacterial growth.
The DEQ is currently conducting further analysis of downstream water systems to assess the risk of contamination spreading via runoff or irrigation channels.
Community urged to report and stay informed
The DEQ is asking residents to report any suspicious water discoloration — especially bright green or blood-red hues — to the state or county health departments.
Community members can find weekly updates on bloom status at deq.wyoming.gov. Officials are also studying long-term prevention measures, including better nutrient management in agricultural runoff zones and aeration systems in recreational lakes.
What to do if you encounter a bloom:
Avoid contact: Do not swim, fish, wade, or boat in affected water;
Keep animals away: Pets and livestock should not drink or enter contaminated waters;
Rinse immediately: If contact occurs, wash thoroughly with clean water;
Seek help: If symptoms develop, contact a healthcare provider or veterinarian; and
Report blooms: Notify the county health department if a bloom is suspected.
As Platte County enters the height of summer, officials emphasize that public awareness and precaution are critical. With conditions favorable for continued bloom activity, residents are encouraged to stay vigilant and avoid risks until water bodies are declared safe.
