Restricted positions
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
Under 5 U.S.C. 3310, competitive examinations for the positions of custodian, elevator operator, guard, and messenger (referred to in this subpart as restricted positions) are restricted to preference eligibles as long as a preference eligible is available. For more information on these restricted positions, refer to the OPM Delegated Examining Operations Handbook.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.