Legal Question in Employment Law in California

Straight Answer: You can terminate this employee assuming the employee to be a non-citizen working in the U.S. Your I-9 document will identify citizenship status. If the person is a U.S. citizen, be careful not to require a S.S. card as proof of identification, as alternate forms are acceptable, and you could expose the company to a form of discrimination if you are targeting enforcement on a person who appears to be of minority or immigrant status.

A practical precautionary measure is to record your requests for confirmation, and timeline of patience to allow the individual to produce documentation. I assume you are engaged in this exercise because you received a SS "mismatch letter" from the SSA, or DHS. A person taking no steps to reapply for a card, or to produce an existing card, who is the subject of such a letter, is also subject to termination for non-cooperation. However, be careful. Mismatch letters are in disrepute in post Obama years, and there are reasons other than illegal immigrant status for a mismatch. Further, it is unlawful and discriminatory to use a mismatch letter or other such discrepancy in SS data to single out an employee for retaliation in opposing illegal employer conduct or engaging in collective bargaining activities.

The Social Security Admin has an online immediate screening data base best used at the hiring process. You can receive 10 verifications immediately. Go to: https://www.socialsecurity.gov/employer/ssnv.htm.