The Immigration Reform and Control Act, which makes it unlawful for companies to hire individuals who are not legally authorized to work in the United States, requires employers to verify the identity and employment eligibility of all new employees using the Immigration and Naturalization Form I-9. Employers must have employees and prospective employees fill out their part of the Form I-9 (eye-nine) when they start to work or within three days of the hiring date. Employees will be required to show some form of identification when completing the form as well as proof of eligibility to work. A driver's license and a Social Security card are the most common accepted documents employees can use to verify these requirements. A U.S. passport can be used to verify both identity and eligibility. Employers should check the I-9 form for completeness and inspect the employee's documents establishing the employee's identity and eligibility to work, noting the employee's document ID (I-D) number and expiration date. Once completed, the form is not sent to the government, but must be kept in the employee's file for at least three years or one year after the employee leaves, whichever is longer. I-9 forms must be available for inspection, copying, and transcription by representatives of the Immigration and Naturalization Service upon request. Under federal law, failure to provide the appropriate documentation of employment eligibility could lead to termination of employment. Employers may also be subject to civil and criminal penalties for failure to comply with provisions of the law.