Fox News medical contributor Dr. Marc Siegel repeatedly urged viewers on Thursday to wear N95 masks if they live in areas impacted by the hazardous smoke from Canadian forest fires. “I’m encouraging them to wear the high-grade masks,” Siegel told Fox News anchor Martha MacCallum. “The danger here is from something called PM2.5, which is the tiny particle that gets deep into your lungs, which is why the American Lung Association calls this an extreme risk hazard to their lungs.” He then noted that people with asthma and other lung diseases should exercise extreme caution, such as staying indoors and carrying extra inhalers to avoid the risk of a stroke or heart attack. Siegel’s warning notably came after several Fox News stars have minimized the health risk of the smoke, mocked the idea of mask-wearing as “insanity,” and ridiculed “snowflakes” worried about the dangers of the cloud of particulate matter. In fact, just an hour later, MacCallum herself was on The Five criticizing Democrats for using the fires to push “climate hysteria.”