I've never seen an explosion-proof motor on a grain mill. At least, not for brewing. Commercial flour mills, yes. A malt mill doesn't do much more than crack the grain and the amount of dust created isn't much.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk