For Immediate Release: June 29, 2020

Media Contact:

Ben Truman │ Vermont Department of Health
802-951-5153 / 802-863-7281
[email protected]

Watch for Cyanobacteria in Warm Summer Waters
Know what blooms look like so you can keep your family and pets safe

BURLINGTON, VT – As Vermonters spend more time in the water this Fourth of July weekend and throughout the summer, health officials want you to know what cyanobacteria blooms look like so you can avoid them.

With the recent heat wave, many Vermont waters are warmer than usual for this time of year. Warm waters create ideal conditions for cyanobacteria (sometimes referred to as blue-green algae) to grow.

Cyanobacteria 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 and wash up along shorelines. They can produce toxins harmful to humans and animals.

Swimming or wading in water with a cyanobacteria bloom may cause skin rashes, diarrhea, a sore throat, stomach problems or more serious health concerns.

“By knowing what a bloom looks like, you’ll know when to stay out of the water,” said Bridget O’Brien, a scientist with the Vermont Department of Health. “You can still have fun in the water — just find another place to swim or play.”

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.

“People with children or pets should be especially aware of potential blooms,” O’Brien said. Children tend to play along the shore where cyanobacteria accumulate and may drink the water when they swim. And dogs are at risk because they can drink the water, lick bloom residue off their fur and eat cyanobacteria scum from the shore.

The Health Department works with the Lake Champlain Committee, the Department of Environmental Conservation and other state agencies, as well as the Lake Champlain Basin Program, recreational site managers, town health officers and drinking water system operators to monitor cyanobacteria conditions.

Vermonters can also help crowd source reporting of conditions. Using a new online form, people can easily send in reports, upload photos and relay the location of cyanobacteria blooms. Staff from the Health Department, Lake Champlain Committee or Department of Environmental Conservation review each report for whether it is a cyanobacteria bloom. If it is, your report will be posted on the Cyanobacteria Tracker.

The Tracker map allows people to check conditions along Lake Champlain and various inland lakes in Vermont, as well as other recreational swimming areas. Sites are identified as "Generally Safe," "Low Alert" or "High Alert." The map shows where cyanobacteria blooms have been reported – but remember that bloom conditions can and do change rapidly.

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.
  • 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 from possible exposure.

As more people are out on beaches and enjoying other water activities, health officials encourage everyone to follow precautions to prevent the spread of COVID-19 – including wearing a face covering and keeping a distance of 6 feet away from people outside your household.

For information about becoming a volunteer monitor, email the Lake Champlain Committee at [email protected].

Learn more about cyanobacteria and what you can do:

For more tips and information about staying healthy while enjoying summer in Vermont, visit

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