39 C.F.R. § 447.21

(a) An employee must not engage, either on a paid or unpaid basis, in teaching, lecturing, or writing for the purpose of the special preparation of a person or class of persons for an examination of the Office of Personnel Management or Board of Examiners for the Foreign Service, or for appointment in the U.S. Postal Service, when these activities are dependent on information obtained as a result of his or her employment with the Postal Service, except when that information has been made available to the general public, or will be made available on request, or when the Postmaster General gives written authorization that the use of nonpublic information is in the public interest.

(b) No employee shall take sick leave to enable himself to engage in outside work.

(c) No employee while acting in his official capacity shall directly or indirectly authorize, permit, or participate in any action, event or course of conduct which subjects any person to discrimination, or results in any person being discriminated against, on the basis of race, color, religion, sex, national origin, or age.

(d) No employee shall engage in criminal, dishonest, notoriously disgraceful or immoral conduct, or other conduct prejudicial to the Postal Service. Conviction of a violation of any criminal statute may be grounds for disciplinary action by the Postal Service in addition to any other penalty imposed by or pursuant to statute.

(e)(1) Except as provided in this paragraph, employees must not drink beer, wine, or other intoxicating beverages while on duty; begin work or return to duty intoxicated; or drink intoxicating beverages in a public place while in uniform. Employees found to be violating this policy may be subject to disciplinary action.

(2) A nonbargaining employee may consume beer or wine at an Officer Approved Event. An Officer Approved Event means: A meeting of Postal Service employees convened by management, such as a working meal, an employee recognition event, or an employee appreciation event; or an event whose primary purpose is to interact with external individuals or entities, such as an industry conference, a sales meeting, or a supplier meeting; that in all cases is either attended by an Officer of the Postal Service who personally decides that the consumption of beer and wine by employees is appropriate, or with respect to which an Officer of the Postal Service has granted specific, written, and advance approval for the consumption of beer and wine by employees.

(3) A nonbargaining employee may consume beer, wine, or other intoxicating beverages at a Postmaster General Approved Event. A Postmaster General Approved Event means any Postal Service-related event with respect to which the Postmaster General personally approves the consumption of beer, wine, or other intoxicating beverages.

(4) No employee may become intoxicated while at an Officer Approved Event or a Postmaster General Approved Event. Except in connection with an Officer Approved Event or a Postmaster General Approved Event occurring at a Postal Service facility or premises, no employee shall have or bring any container of beer or wine into any Postal Service facility or premises, whether the container has been opened or not. Intoxicating beverages other than beer and wine may never be brought into any Postal Service facility or premises under any circumstances.

(f) Illegal use of drugs may be grounds for removal from the Postal Service.

(g) No employee while on property owned or leased by the Postal Service or the United States or while on duty, shall participate in any gambling activity, including the operation of a gambling device, in conducting or acting as an agent for a lottery or pool, in conducting a game for money or property, or in selling or purchasing a numbers slip or ticket.