U.S.C. Title 26, Section 6104 (e)
(e) Public inspection of certain annual returns and applications for exemption
(1) Annual returns
(A) In general
During the 3-year period beginning on the filing date - (i) a copy of the annual return filed under section 6033 (relating to returns by exempt organizations) by any organization to which this paragraph applies shall be made available by such organization for inspection during regular business hours by any individual at the principal office of such organization and, if such organization regularly maintains 1 or more regional or district offices having 3 or more employees, at each such regional or district office, and
(ii) upon request of an individual made at such principal office or such a regional or district office, a copy of such annual return shall be provided to such individual without charge other than a reasonable fee for any reproduction and mailing costs.
The request described in clause (ii) must be made in person or in writing. If the request under clause (ii) is made in person, such copy shall be provided immediately and, if made in writing, shall be provided within 30 days.