“ Restriction.—An agency may not include the social security account number of an individual on any document sent by mail unless the head of the agency determines that the inclusion of the social security account number on the document is necessary. ”

“ Such regulations shall include—
(1) instructions for the partial redaction of social security account numbers where feasible; and
(2) a requirement that social security account numbers not be visible on the outside of any package sent by mail. ”