I have never been assured beyond a shadow of a doubt that these don't have asbestos somewhere in them. Same for the rheostats....
No problems that I've seen. The transformer contains ceramic plates and insulators. The balance of insulating materials are thick paper. The rheostat is made up from basic non-hazardous materials (ceramic insulators, carbon slider & base metal). The only unknown would be the possible use of lead base paint.
God Bless,
"Pappy"