It will never happen. One of the anti-smoker groups sued OSHA in an attempt to force them to set a level at zero. the lawsuit had to be dropped because OSHA said if they set a level it would not be at zero.
Had OSHA set a level most likely all smoking bans would wind up being tossed out the window.......the antis can't have that, can they?????
In addition, an exposure level already exists for most of the "toxins" found in tobacco smoke. You can find it in most MSDS sheets required to be on file at any manufacturing facility. If they set SHS exposure limits to zero, then all "toxins" in SHS would be at zero and this country would grind to a halt!