For Immediate Release: June 30, 2025
Media Contacts:
Kyle Casteel – Media Lead
Communication Office │ Department of Health
802-863-7280 │ [email protected]
Peter Isles – Aquatic Biologist
Department of Environmental Conservation
802-490-6130 | [email protected]
Learn to Spot Cyanobacteria in the Water to Stay Safe All Summer Long
Cyanobacteria blooms may appear in Vermont’s lakes and ponds, and can harm your health
WATERBURY, VT — It’s the time of year to start checking Vermont’s waters for cyanobacteria blooms before you swim, play, or bring your pets, so you can have fun in the water safely.
Cyanobacteria (also known as blue-green algae) are tiny microorganisms that are a natural part of freshwater ecosystems. Under certain conditions, the bacteria can grow and create blooms that float on the water’s surface and wash up along shorelines, posing health risks to humans and animals.
The blooms can produce harmful toxins, so if you see them, it’s best to stay out of the water. Swimming or wading in water with a cyanobacteria bloom may cause skin rashes, diarrhea, a sore throat, stomach problems, or more serious health concerns.
“Cyanobacteria blooms can be especially dangerous to children who accidentally swallow the water when playing, and for pets that may drink from the shoreline or lick water off their coats,” said Bridget O’Brien, an environmental health scientist with the Department of Health.
How to know what a bloom looks like:
Cyanobacteria blooms are usually green or blue-green and can make the water look like pea soup or spilled paint, but they can be other colors and consistencies too.
- See a video and photos of what is – and isn’t – a cyanobacteria bloom: HealthVermont.gov/Cyanobacteria
If you think you’ve spotted a cyanobacteria bloom:
- Avoid contact with the water. If you come in contact with cyanobacteria, rinse off thoroughly as soon as possible.
- Do not let pets or livestock swim in or drink the water.
- Talk with your health care provider if you have concerns about possible exposure.
- Report the possible bloom to the beach manager and/or the local Town Health Officer. You can also report suspected blooms on the state’s Cyanobacteria tracker.
The Health Department and the Department of Environmental Conservation (DEC) work closely with the Lake Champlain Committee, which trains volunteers around the state to monitor Lake Champlain and other bodies of water and report conditions through the Cyanobacteria Tracker. Anyone can report and upload photos of suspected cyanobacteria blooms using the tracker’s online form. Reports are reviewed, confirmed, and posted to the tracker.
“The reports about bloom conditions submitted by volunteers and the public have been invaluable for understanding where blooms occur in the region, which can allow us to target monitoring efforts and remediation measures," said Peter Isles, an aquatic biologist with DEC.
People can check the map to see where cyanobacteria blooms have been reported recently, but the map does not show up-to-the-minute conditions at your favorite swimming area – caution is always advised.
Bloom conditions can and do change quickly, and not all locations are monitored. Vermonters should learn what blooms commonly look like and always pay attention to any posted warning and closure signs. People can also check with their town for conditions at locally managed beaches.
Learn more about cyanobacteria and find translated information and “Cyanobacteria Alert” and “Beach Closed” signs in 12 languages.
The Lake Champlain Committee coordinates a program of volunteer cyanobacteria monitors. To get involved, email [email protected].
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