Township documents containing all or more than four sequential digits of a Social Security number shall be sent only in cases where state or federal law, rule, regulation or court order or rule authorizes, permits or requires that a Social Security number appear in the document. Documents containing all or more than four sequential digits of a Social Security number that are sent through the mail shall not reveal the number through the envelope window or otherwise be visible from outside the envelope or package.
(Board and Administrative Policies Manual, § 4.68)