39 U.S.C. § 3204 — Restrictions on use of penalty mail

(a) Unless this section or section 3220(a) provides otherwise, a United States officer, executive department, or independent establishment may send an article or document as penalty mail only if the department previously received a request for it or the mailing is required by law.

(b) This does not prohibit penalty mail consisting of: (1) enclosures reasonably related to official correspondence; (2) census information authorized by title 13; (3) material about selling Government securities; (4) forms, blanks, statutes, rules, regulations, instructions, administrative orders, and interpretations needed to administer the office; (5) agricultural bulletins; (6) lists of public documents offered by the Superintendent of Documents; (7) announcements that maps, atlases, statistical reports, or other reports are for sale by the Federal Power Commission as authorized by section 825k of title 16; or (8) articles or documents sent to educational institutions, public libraries, or Federal, State, or other public authorities.