In 1991, the Occupational Safety and Health Administration (OSHA), part of the Department of Labor (defendant), promulgated safety standards regarding the removal of needles used to draw blood. The 1991 regulation allowed for the removal of contaminated needles in certain circumstances, but provided that if such removal was allowed, it must be accomplished through the use of a mechanical device or a one-handed technique. The agency initially declined to enforce this section against employers who supplied their employees with reusable blood tube holders. In 2003, OSHA issued a guidance document stating that reusable blood tube holders likely violated the 1991 regulation. Although its parent company operated facilities that employed single-use blood tube holders, MetWest, Inc. (plaintiff) typically supplied phlebotomists with reusable holders. In 2004, an OSHA compliance officer issued a citation to MetWest for allowing the removal of needles from reusable blood tube holders in violation of the 1991 regulation. An Administrative Law Judge and the Occupational Safety and Health Review Commission upheld the citation. MetWest petitioned for judicial review.