People asked to avoid and report harmful blue-green algae blooms in Wyoming - Casper, WY Oil City News
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People asked to avoid and report harmful blue-green algae blooms in Wyoming

A blue-green algae bloom at Pathfinder Reservoir in 2018. (Wyoming DEQ)

CASPER, Wyo. — As summer approaches and people head out to Wyoming’s lakes and reservoirs, they should avoid and report any possible cyanobacterial blooms.

While there are currently no cyanobacterial blooms reported in the state, the Wyoming Department of Environmental Quality said in a Monday, June 15 notice that the public should keep themselves and their pets away from such waters if the blooms appear to be present.

“Cyanobacteria, also known as blue-green algae, can form harmful cyanobacterial blooms (HCBs) that produce toxins and other irritants that pose a risk to human and animal health,” the notice states. “HCBs typically occur when water temperatures increase in still or slow-moving water, or when wind aggregates cyanobacteria near shorelines.”

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These blooms are generally blue or green in color and could appear as green water, grass clippings, scum, floating mats or spilled paint on the surface of the water, according to the notice.

“HCBs may also be attached to rocks, sediment, or plants at the bottom of a waterbody,” Wyoming DEQ added. “When HCBs form, they may last days, weeks or even months.”

“Suspected HCBs can be reported to DEQ by calling 307-777-7501 or submitting a complaint online at Once reported, DEQ will investigate potential blooms to determine if they are harmful.The Wyoming Department of Health will issue advisories for publicly accessible waters when levels of cyanobacteria and/or toxins pose a risk to people engaging in swimming or similar types of water recreation activities.”

Advisories of the harmful blooms and places where the DEQ is investigating will be posted online. The website shows where such blooms occurred in Wyoming in recent years. In the Casper area, Pathfinder Reservoir saw such blooms the last two yeas and Alcova saw such blooms in 2018.

The notice also provides safety tips regarding waters where such blooms may be present:

-Avoid contact with water in the vicinity of the bloom, especially in areas where cyanobacteria are dense and form scum.

-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.

Wyoming DEQ

“Seek medical attention or a veterinarian if a person or animal is experiencing adverse health effects after exposure to a cyanobacterial bloom,” the notice adds. “Young children, pregnant women, people with weak immune systems and animals are especially at risk.”

“Questions regarding general health risks and symptoms related to a cyanobacterial bloom can be referred to Dr. Karl Musgrave, state public health veterinarian and environmental health epidemiologist with WDH at 307-777-5825. Health information is also available at For more information, visit the DEQ’s Wyoming’s HCB webpage at”