State regulators Tuesday held a workshop to discuss the health impacts of wind turbine noise and is considering whether to adopt new sound standards.

Most wind projects in Vermont are limited to a 45-decibel sound level, which the Vermont Public Service Board adopted based on guidelines developed by the World Health Organization. But proponents of new noise standards say the state must set a limit that accounts for temperature, humidity, location, wind speeds and the like -- all of which they say cause extreme changes in the level of noise the turbines create.

Sandy Reider is a primary care physician in Lyndonville. He said he has treated several patients living near turbines who experience similar symptoms, including nausea, insomnia and headaches. He said these symptoms could be linked to exposure to turbine noise.

There are few studies that confirm Reider's anecdotal findings, but "Just because the prevailing models fail to explain observed adverse health effects, does not mean they do not exist," he said.

Other speakers say more research is needed to determine a causal link between noise exposure and adverse health effects.

David Grass is environmental health surveillance chief for the Vermont Department of Health. He said improperly sited turbines can cause sleep disturbance if the noise is greater than 40 decibels inside the home. And this can lead to other health consequences, he said.

However, he said the role of annoyance is "yet to be nailed down," in part because there are so few residents living near wind turbines to study.


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Nonetheless, he said sleep disruption can be addressed by reducing the perception of noise. He and others said when the turbines are visible, the perceived health effect increases.

He questioned whether certain studies on the issue could even be generalized to Vermont's unique characteristics. "There remain a lot of unanswered questions and uncertainties," he said.