5 C.F.R. § 339.202

OPM may establish and/or approve medical standards for a Governmentwide occupation (i.e., an occupation common to more than one agency) or approve revisions to its established medical standards. An individual agency may establish medical standards for positions that predominate in that agency (i.e., where the agency has 50 percent or more of the positions in a particular occupation). Such standards must be justified on the basis that the duties of the positions are arduous or hazardous, or require a certain level of health status for successful performance when the nature of the positions involves a high degree of responsibility toward the public or sensitive national security concerns. The rationale for establishing the standard must be documented and supported by a study(ies) or evaluation(s) establishing the medical standard is job-related to the occupation(s). Medical standards established by agencies must be approved by OPM prior to implementation. Standards established by OPM or an agency must be:

(a) Established by written directive and uniformly applied, and

(b) Directly related to the actual performance and requirements necessary for the performance of the duties of the position.