Opponents of industrial wind turbine developments in Ontario are celebrating a court ruling that will force the province’s chief medical officer of health to testify about the known noise and health risks of wind power developments.

Ontario Superior Court Justice Mary Sanderson issued an order Wednesday that requires Dr. Arlene King to testify in the case of Shawn and Trisha Drennan of Ashfield Township by Lake Huron in southwestern Ontario.

Shawn and Trisha Drennan are fighting a wind turbine project near their farm in Ashfield Township. (Dave Seglins/CBC)

The couple is fighting the proposed Kingsbridge II project by Capital Power Corp. to install 150 wind turbines, one of which will be within 650 metres of their farm north of Goderich.

Based on reports of residents near other wind developments in Ontario who complain of vertigo, tinnitus, and sleep disorders stemming from the turbines, the Drennans have gone to court demanding that private gag orders on a number of landowners in neighbouring communities be lifted.

Those people complained of turbine noise and health issues, yet agreed to sell their properties back to power companies in exchange for agreeing to keep quiet.

In their fight, the Drennans want to challenge King on her 2010 review of international literature on wind turbine science, which has been used by the government of Ontario to defend its major expansion into wind power. The government claimed in a news release that King determined “there is no direct causal link between wind turbines and adverse health effects.”

Gaps in research

But residents and groups opposed to the installation of large industrial wind farms near peoples’ homes have long criticized King's report, pointing out she didn't conduct an empirical study within Ontario, and she didn't talk to residents now living close to turbines.

What’s more, they complain the government has oversimplified her findings, failing to point out King’s own conclusions that there are gaps within the scientific research around how to measure the health impact of turbine noise.

Provincial lawyers tried to overturn a summons for King to testify. However, in Wednesday’s ruling, Sanderson rejected the government’s argument that the Drennans' request for her testimony was an abuse of process.

Sanderson pointed out that Dr. King had indeed found limits to the science on wind power.

"Dr. King identified two data gaps in her report," the judge wrote.

One of the data gaps involved "sound measurements at residential areas around wind turbines and comparisons with sound levels around other rural and urban areas, to assess actual ambient noise levels prevalent in Ontario.”

The other gap identified by King was making noise level assessments to “mak[e] an informed decision on whether epidemiological studies looking at health outcomes will be useful.”

A CBC News investigation last fall found scores of residents who complain that wind turbine installations have made them sick and made their homes unlivable.

The province has changed the regulations requiring all new turbines to be set back a distance of no less than 550 metres. However, the Environmental Review Tribunal, a provincial regulator concluded last summer that there is evidence that turbines can cause harm.

Last week, Health Canada waded in, acknowledging there are gaps in the science and has committed to conduct a two-year study of the health of 2,000 residents at eight to 12 wind farms across Canada. The study will examine what affect wind turbine noise is having on their lives.