Work is underway to address a dark substance leaking from wind turbines in Harrow, Essex town council heard on Monday. Denny Richard, the CEO of the AIM Harrow Wind Farm, provided an update to council in response to residents’ concerns raised in recent months. “There has been some leaks in the hydraulic systems,” Richard said at the town’s regular council meeting. “That mixture of blade bearing grease and hydraulic fluid will start to escape the wind turbine and will travel down the blades and deposit onto the components.” CTV News first reported on the leaks in April, when residents voiced fears over how it could impact the environment. On Monday, Richard told council, to date, they have finished cleaning seven of the 24 turbines. The effort has been made difficult due to the lengthy process, a limited number of certified technicians to do the work, and inclement weather, including rain and lightning. “It takes a little over a week to do a single blade, and there’s three blades, and then there’s parts of the tower as well, which need to be cleaned,” explained Richard. Further adding to the difficulty, Richard noted turbines which look especially dirty can be easier to clean, and those bearing less visible marks could be more difficult to refurbish. Because of the ranging factors, the company cannot provide a firm timeline for when the cleaning will be completed. In response to questions about substances falling into the soil, the company head noted environmental consultants did not find oil or grease deposits in nearby land. “To me, it means that it’s just been dispersed, if there was any, to the point where it’s undetectable,” he noted, adding the cleaning substance is biodegradable. As part of the work, Richard noted upgrades are underway to ensure there’s no future leaks. So far, crews have completed 51 per cent of the upgrades. “We intend to continue operating in the community for years to come with providing clean, reliable, renewable energy, and by also committing to ensuring that we do not have repeat issues such as these,“ Richard said.