Agreed...you can indeed legislate and reduce the symptoms of stupidity from occurring. In fact, it is the only practical way to stop stupid from affecting the rest of us.

Anyway, there are several sites an articles that do indeed say that diesel particulate cause cancer and contain benzene, arsenic, formaldehydes, and several nitric oxides. The OSHA site is among them as well as longer-term studies that idiot the same

Obviously, commercial older tricks like the ones that carry stone chips etc..those are the worst offenders.