Keyhole investigating possible blue-green algae presence

The bacteria in question, harmful cyanobacterial bloom, is a blue-green algae that blooms on the surface of water, usually during hot summer months and produces potentially harmful toxins into the surrounding water, according to a park press release.

An early August visitor notified parks workers that a dog had become very sick and died after visiting the park and playing in the water. The visitor said she knows of three other dogs that also were ill and went on antibiotics following visits to Keyhole, said Wyoming State Parks Deputy Director Nick Neylon.

It is unclear if the death and illnesses are directly connected to the park, but the department is doing its due diligence to learn whether bacteria is present in the water, Neylon said.

“They (Department of Environmental Quality) told us they would get somebody out there as soon as possible,” Neylon said.

Once the water is tested, the results come in fairly quickly, Neylon said.

The water in the area of the park near the upper end of Cottonwood Bay is the only section being investigated, which may affect the Pronghorn, Tatanka, Arch Rock, Cottonwood and Homestead campgrounds nearby, the press release said.

Satellite images recently taken of the area do not indicate HCB and visual inspections conducted by park staff have not spotted any signs of an HCB bloom. The Wyoming Department of Health has been notified as DEQ staff investigate, the press release said.

The lake is not closed. However, warning signs have been posted and the park advises that visitors proceed with caution.

HCBs, also known as blue-green algae, usually bloom in still or slow-moving water during summer months. The episodes can range in length from several hours to multiple months, according to the DEQ.

The blooms that appear during an outbreak can produce toxins and other irritants that can have deleterious effects on the health of people, pets and livestock. Once harmful levels of HCBs are proven, WDH typically issues safety advisories.

“We already put out the signs that we would put out in that case (if found), we would be a little bit more aggressive in telling people that yes, this is, in fact, happening,” Neylon said. “We do not typically close areas, we warn people to be more careful.”

Water with, and the water surrounding, high concentrations of HCBs, especially where it is visibly dense, should be avoided. The infected water also should not be ingested. Even boiling, filtering or otherwise treating the water will not remove the toxins, according to the WDH.

Also, pets and livestock should not drink the water, eat the scum or lick their fur after coming in contact with the bloom. People or animals who do come in contact with the bloom or water in its vicinity should rinse off with clean water immediately, according to the WDH.

There was a confirmed HCB finding at Keyhole in 2019, Neylon said.