President Donald Trump of the United States of America has made quite the claim. At the National Republican Congressional Committee fundraising dinner earlier this week, he took a tilt at 'windmills'.
He's referring to wind turbines, one of the leading technologies for renewable energy, and the target of a very long-running smear campaign.
And, while he's at least partially right - wind farms can negatively impact property values (although the 75 percent figure is more than a little exaggerated) - he's very off-base on the cancer thing.
In fact, according to an expert panel review conducted for the American and Canadian Wind Energy Associations, "there is no evidence that audible or sub-audible sounds emitted by wind turbines have any direct adverse physiological effects."
It's not impossible that the noise from wind turbines could be annoying, if they were in close-enough proximity to residences. Most regions have setback laws that govern how close a wind turbine can be placed to a home, generally at least 300 metres (984 feet).
At that distance, according to GE, the sound level is about 43 decibels.
"To put that in context, the average air conditioner can reach 50 decibels of noise, and most refrigerators run at around 40 decibels," wrote editor-in-chief of GE Reports Thomas Kellner in a 2014 post to the company's website.
That's consistent with findings from the Victorian Environmental Protection Agency in Australia. At a distance of 500 to 1,000 metres, the decibel level is around 35-45 - much quieter than the 60 decibels measured in a busy office environment.
Turbines also produce sound below the range of human hearing, called infrasound. At high-enough volume, infrasound has been found to make us feel dizzy, nauseous and headachey. Generally, it's only above 110 decibels that this effect occurs.
Since we can hear infrasound over about 85 decibels - a little louder than a vacuum cleaner - you would definitely be aware of the sound at that point.
So, can sound cause cancer? Not that we know of. Cancer is the result of gene mutations, and there is no evidence that they can be triggered by noise.
Scientists have noticed a correlation between constant proximity to traffic noise and a higher incidence of cancer… but, well, proximity to traffic noise is also proximity to traffic exhausts - a known and particularly potent carcinogen.
And when it comes to causes of cancer, according to the US Government's National Institute of Environmental Health Services, "toxic outputs of fossil fuel-based power generation and transportation, such as sulphur oxide, nitrous oxides, heavy metals, and particulate matter" are of grave concern.
A 2009 study found that fossil fuel air pollution accounted for 5 percent of all male cancer deaths and 3 percent of all female cancer deaths in the US between 1970 and 1994.
And it's not just cancer. In 2017, a World Health Organisation report found that 570,000 children under the age of five are dying every year worldwide because of pollution-related illnesses, including pneumonia and asthma.
Meanwhile, there has not been a single documented human death due to an illness caused by a wind turbine. Not one.
Even deaths caused by accidents are low. Compare that to half a million children killed every year by air pollution, including that from fossil fuels.
The best case scenario for President Trump's claim is that he genuinely believes what he is saying, showing he is ignorant of decades of research. That's not great, for a president.
But in the worst case scenario, he is pushing a dangerous, world-destroying lie for political gain.