When making personnel decisions – including hiring, retention, promotion, and reassignment – employers sometimes want to consider the backgrounds of applicants and employees. For example, some employers might try to find out about the person’s work history, education, criminal record, financial history, medical history, or use of social media. Except for certain restrictions related to medical and genetic information, it’s not illegal for an employer to ask questions about an applicant’s or employee’s background, or to require a background check.
A joint publication of the Equal Employment Opportunity Commission and the Federal Trade Commission.
https://www.eeoc.gov/eeoc/publications/upload/eeoc_ftc_background_checks_employers.pdf
https://www.eeoc.gov/eeoc/publications/background_checks_employers.cfm