I don't know about your area, but in many parts of Canada railway companies are hyper-sensitive about fires along the tracks.

I know some local wildfires are caused by stuck brake shoes, bad bearings, etc. sending a spray of sparks into the dry grass beside the tracks. Mostly, these are contained along the line, but in a very dry year things can get out of hand, and the railway is blamed/fined/liable.

An employee causing a fire, even by accident, would put the company on the spot. That may be where the "fire hazard" worry could come from. Once there's a bad incident, there's a blanket policy or a law, applied even where it may not make much sense. If the company doesn't enforce it, and an employee causes an accidental fire, the CEO could find himself in court or worse.

My 2-cents' worth.