The issue with waste oil isn't the oil itself, but rather the contaminants that are in it from the engine it used to be in... From my understanding the OSHA and EPA rules on contact, exposure, disposal, etc. are MUCH more stringent on waste oil than they are with new oil.
Used oil is also considered a causitive agent for chemical contact dermatitis (aka skin rash) to a MUCH larger extent than fresh oil...
Gooserider
Used oil is also considered a causitive agent for chemical contact dermatitis (aka skin rash) to a MUCH larger extent than fresh oil...
Gooserider