The FLSA allows an employer to exclude time spent "changing clothes" from working time as long as the employees agree to this in a collective bargaining agreement or if there is a long history of non-payment in the industry and the employees knew about and agreed to the practice. . The plaintiff's in Sandifer are members of a union 29 U.S.C. § 203(o)who work at US Steel Corporation's Gary Works, the largest integrated steel mill in North America. Before starting their shifts, the workers put on safety gear in a locker room. Because of the large size of the plant some of the workers traveled to their work stations on buses. After their shifts ended, they returned to the locker room and removed the gear. The process of putting on gear and traveling to the work site at the start of the day and then returning to the locker room and removing the gear at the end of the day sometimes added up to several hours per week, which is where the money adds up.
The Supreme Court declined to take up a second issue of whether changing clothes can constitute a principal activity under the FLSA, even if it is excluded from working time under § 203(o). If this were the case, then all the time the employees spend on a bus riding to and from the locker rooms would be compensable working time under the FLSA regardless of whether their gear is clothes.