Any of it.
Wayne County (MI) Clean Indoor Air Regulation (http://waynecounty.com/hhSvcs/environ/cleanIndoorAir.htm) effective June 15 2005, smoking at worksites in Wayne County, Michigan and within six feet of any worksite facility entrance, window or ventilation system is prohibited.
My bad, looks like the ban is Wayne county too, not just the 6 feet thing.