bearing an official seal, A Certificate of U.S. Citizenship (Form N-560 or N-561), A Certificate of Naturalization (Form N-550 or N-570), Native American tribal document, U.S. Citizen ID Card (Form I-197), An ID Card for the use of a Resident Citizen in the United States (Form I-179), An unexpired employment authorization card issued by the Dept. of Homeland Security (other than those included on List A) or Consular Report of Birth Abroad (Form FS-240). U.S. citizens who have lost their social security card can apply for a duplicate at the Social Security Administration. Employees who supply an item from List C (to establish employment eligibility) must also supply an item from List B (to establish identity). Reverification Employers must update or reverify certain ID documents at or prior to their expiration date. This does not apply to already presented and accepted non-expired U.S. Passports or Permanent Resident Cards when they reach their expiration date, nor to any List B documents (e.g., state driver's licenses and state IDs). The USCIS website, in the Employer section, Employer Bulletins, lists the limited requirements and allowed instances for reverification. For U.S. citizens, I-9s are valid continuously unless a break of more than a year of employment occurs. International employees on F-1 (student), H-1B (specialty occupation), or J-1 (exchange visitor) visas must have their I-9 reverified each time their visa has expired with a new work authorization permit (renewed visa with work authorization, EAD, Permanent Residence Card, etc.). Retention Employers must retain a Form I-9 for all current employees. Employers must also retain a Form I-9 for three years after the date of hire, or one year after the date employment ends, whichever is later. Employers must show their employees' I-9 form any time the immigration or labor authority requests it. Anti-discrimination provisions The Immigration Reform and Control Act which introduced the requirement leading to the promulgation of the I-9 form also included anti-discrimination provisions. Under the Act, most U.S. citizens, permanent residents, temporary residents, asylees or refugees who are legally allowed to work in the United States cannot be discriminated against on the basis of national origin or citizenship status. This provision applies to employers of three or more workers and covers both hiring and termination decisions. In addition, an employer must accept any valid document or combination of documents specified in the I-9 form as long as the documents appear genuine. For example,