; and performed rescue, recovery, demolition, debris cleanup, or other related services at the Shanksville, Pennsylvania, site of the terrorist-related aircraft crash of September 11, 2001, during the period beginning on September 11, 2001, and ending on October 3, 2001. (2) Exception An alien shall not be provided any benefit under this section if the Secretary of Homeland Security determines that the alien has willfully made a material misrepresentation or material omission in the proffer of information described in paragraph (1)(C). (c) Work authorization The Secretary of Homeland Security may authorize an alien who has applied for adjustment of status under subsection (a) to engage in employment in the United States during the pendency of such application. (d) Construction Nothing in this section shall be construed to limit the existing authority of the Secretary of Homeland Security on the date of the enactment of this Act to require any form or other submission of information or to perform any background or security check for the purpose of determining the admissibility, or eligibility under this section, of any alien. (e) Waiver of regulations The Secretary of Homeland Security shall issue guidance to carry out this section not later than 6 months after the date of the enactment of this Act, but is not required to promulgate regulations prior to implementing this section. (f) No offset in number of visas available When an alien is granted the status of having been lawfully admitted for permanent residence under this section, the Secretary of State shall not be required to reduce the number of immigrant visas authorized to be issued under the Immigration and Nationality Act ( 8 U.S.C. 1101 et seq.). (g) Definitions For purposes of this section: (1) The term applicable Federal tax liability means liability for Federal taxes, including penalties and interest, owed for any year for which the statutory period for assessment of any deficiency for such taxes has not expired. (2) Except as otherwise specifically