High levels of cyanobacteria were detected by the Wyoming Department of Environmental Quality last week in Boysen Reservoir, prompting an alert for recreationists.
The DEQ wrote on its Facebook page that sampling indicated very high "cyanobacteria cell densities at the Brannon Boat Ramp, well above the 20,000 cells per millimeter of water threshold identified in the Harmful Algal Bloom Action Plan."
"At this time, Brannon Boat Ramp is the only area identified as having an algal bloom issue," the post noted.
The Department of Health has been working with Boysen State Park to ensure that advisory signs are posted. Those concerned about any health issues should not swim in the Brannon Boat Ramp area.
Algal blooms happen most years, and may affect people and animals differently.
"The advisory recommends that visitors do not swim, drink water, rinse fish or allow pets to come into contact with the water in the affected area," according to a Wyoming State Parks' Facebook post. "No other areas of the park are affected at this time."