Recently, rumors started spreading on social media that many of the devastating wildfires burning throughout the Pacific Northwest were intentionally started by “antifa,” a small, loose collective of left-wing activists that is often demonized by conservatives. The debunked claim was even promoted to millions of listeners by popular podcaster Joe Rogan.

Some people in rural Oregon have taken the unfounded rumors so seriously that they have begun to conduct armed patrols of their towns, looking for masked antifa activists. Others have refused to abide by evacuation orders, choosing instead to stay in their homes, despite advancing fires, to defend their property against what they believe are approaching hordes of anarchists.

Yet, there’s no credible evidence that antifa activists are responsible for starting any of the fires now burning throughout the Northwest. Even local law enforcement and the FBI have taken to social media to dispel the rumors.

But blaming wildfires in the Pacific Northwest on radical activists is not new. The region has long been home to both far-left politics and massive forest fires. And, in the past, just as today, rumors about radical arsonists setting blazes has served to stoke fears about activists and shift attention away from the real causes of wildfire.

The first group to be regularly charged with setting forest fires was the Industrial Workers of the World (IWW), a radical labor union founded in 1905. Though a national organization, the Wobblies, as the union’s members were more popularly known, were especially active in the Northwest’s timber industry.

Unlike most of the American labor movement, the IWW welcomed women, immigrants and workers of color. The union’s members literally stood on soapboxes in cities and preached about the evils of industry, while their songs promised a time in the not too distant future when workers would join and overthrow the capitalist system.

The IWW was also a controversial group because its activism extended beyond boycotts and strikes. Wobbly leaders often endorsed industrial sabotage, breaking equipment or destroying worksites when employers didn’t pay fair wages or provide decent working conditions.

The IWW’s radicalism along with its willingness to destroy property may explain why many Northwesterners were quick to jump to the conclusion that Wobblies were responsible for the alarming number of fires that burned through Northwest forests in the early 20th century.