I sure didn't know that the plastic liners were replaced every fill.  They definitely are not in the herbicide business, because I've seen more then just a couple of those filled. 

Our IBC's and jugs (and drums, for that matter) are not in the hot work area although strictly speaking they are not separated except by about 50' of space.  Our used oil storage is not even in the same building as the shop.  

Now that I think about it, I have seen some fairly volatile substances (methanol and thinner come to mind) in plastic containers.   I'm not sure I'm entirely comfortable with that.  

I think a much greater concern is the trend of hanging 200 gallons or so of diesel fuel in a plastic tank surrounding the engine on a machine which is an inherent fire hazard to begin with.  If our cotton strippers had plastic fuel tanks they certainly would have both been destroyed in the limited amount of time we operated them.