For Immediate Release: June 29, 2023 

Media Contact:  
Katie Warchut │ Vermont Department of Health 
[email protected]   

Peter Isles, Aquatic Biologist 
Department of Environmental Conservation 
[email protected]  



Know What Cyanobacteria Look Like This Summer 

Enjoy Vermont waters safely by avoiding potentially harmful blooms 

BURLINGTON, VT – As many Vermonters head for the water this Fourth of July weekend, it’s a good time to know what cyanobacteria blooms look like so you can avoid them. Cyanobacteria blooms can be harmful to your health and have already closed some beaches recently. 

Cyanobacteria (sometimes called blue-green algae) are tiny microorganisms that are a natural part of fresh water ecosystems. Under certain conditions, cyanobacteria can multiply quickly, creating blooms on the water’s surface that can also wash up along shorelines. Blooms can produce toxins harmful to humans and animals. 

See a video of cyanobacteria and photos of what is – and isn’t – a bloom at 

“Take a quick scan of the water before you, your kids or your pets go in,” said Bridget O’Brien, an environmental health scientist with the Vermont Department of Health. “If you see any scummy or discolored water – or if you are unsure – play it safe and find another place to go.” 

Swimming or wading in water with a cyanobacteria bloom may cause skin rashes, diarrhea, a sore throat, stomach problems or more serious health concerns. Children and pets are most at risk. Children tend to play along the shore where cyanobacteria accumulate and may drink the water when they swim. And dogs may drink the water, lick bloom residue off their fur, and eat cyanobacteria scum from the shore. 

“We can all safely enjoy Vermont’s lakes and ponds if we learn to recognize and avoid contact with cyanobacteria,” said Department of Environmental Conservation Commissioner John Beling. “If you think you see a bloom, be sure to report it.” 

Vermonters can report cyanobacteria blooms using an online form that also allows for easy upload of photos. These reports are reviewed by staff from the Health Department, Lake Champlain Committee or Department of Environmental Conservation. Confirmed reports, along with location and any photos, are posted on the Cyanobacteria Tracker.  

The Departments of Health and Environmental Conservation work closely with the Lake Champlain Committee to keep tabs on lakeshore conditions. For the past 20 years, the Lake Champlain Committee has trained community volunteers to monitor for cyanobacteria. These volunteer monitors, along with municipal recreational staff, as well as the Departments of Health and Environmental Conservation, provide data about where blooms are currently present, which get posted on the Health Department’s Cyanobacteria Tracker

While the Cyanobacteria Tracker shows where cyanobacteria blooms have been reported recently, O’Brien cautions Vermonters not to rely on the map alone.  

“Bloom conditions can and do change quickly, so it is still important to check the water when you get there. And be sure to pay attention to any posted signs warning of blooms or beach closures,” O’Brien said. 

Communities and others can access translated cyanobacteria information sheets and signs – “cyanobacteria alert” and “beach closed” – available in 12 languages at

If you think you see a cyanobacteria bloom

  • Avoid contact with the water. 
  • Do not let pets or livestock swim in or drink the water. 
  • Report the bloom.  

If you come in contact with cyanobacteria: 

  • Rinse yourself off thoroughly as soon as possible.  
  • Talk with your health care provider if you have concerns about possible exposure. 

Learn more about cyanobacteria and what you can do: 

For information about becoming a volunteer monitor, fill out the Lake Champlain Committee’s  Cyanobacteria Monitor Interest Form

For swim safety tips and more information about staying healthy while enjoying summer in Vermont:

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About the Department of Health 

We have been the state's public health agency for more than 130 years, working every day to protect and promote the health of Vermonters. Visit  Join us @HealthVermont on FacebookTwitterInstagramYouTube  


About the Department of Environmental Conservation 

The Department of Environmental Conservation is responsible for protecting Vermont's natural resources and safeguarding human health for the benefit of this and future generations. Visit and follow the Department of Environmental Conservation on Facebook and Instagram. 


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