Hoods of Color

While I can't say it is true of all fabs, all the ones I visited required vendors, contractors, and cleaning services to wear a different colored hood than the fab's employees. Generally, employees wore white hoods, vendors wore blue hoods, contractors wore tan hoods, and the cleaning contractors wore yellow hoods. At quick glance, you can notice if a unauthorized person was touching equipment or computers by their hood color. Contractors and cleaners were not to touch equipment and computers. Vendors could tough the equipment they represent, but not the computers on the 50-yard-line. And asking a white hood was generally the best bet to find a responsible person for an area. While not the perfect system, it certainly helps when the only ~150cm2 is recognizable of your colleagues.