Vermont health officials say elevated toxin levels have been found in a blue-green algae bloom in Missisquoi Bay and that swimming and bathing in the water where it’s present should be avoided.
In a health advisory, the state Department of Health said skin contact with algae-contaminated water can cause irritation or rash and that consumption of it can lead to diarrhea, vomiting or nausea.
The state has notified North Hero, St. Albans and Swanton officials, telling them to closely monitor for blooms and to close public beaches if they see the blue-green algae.
It’s the first time the state has issued such a warning for Lake Champlain since 2006.
William Bress, state toxicologist, said Friday that algae has been present in the lake before, but that the levels of one toxin in particular – microcystin – have risen past acceptable levels.
"It looks like a greenish oil sheen," he said of the blue-green algae.
Blue-green algae is the commonly used name for cyanobacteria, a bacteria that can produce a toxin.