The Age Discrimination in Employment Act of 1967 (ADEA) provides protection to workers and applicants that are 40 and older. It prohibits age based employment discrimination regarding any term, condition, or privilege of employment, including hiring, firing, promotion, layoff, compensation, benefits, job assignments, and training. The ADEA's protections apply to both employees and job applicants. Like other employment based anti-discrimination laws, the ADEA forbids an employer from retaliating against an individual for filing an age discrimination charge, opposing age based employment discrimination, or otherwise testifying or participating in an ADEA investigation, proceeding, or lawsuit. It applies to employers with 20 or more employees. Under the ADEA, it is unlawful to include age requirements in job notices or advertisements, unless age is a "bona fide occupational qualification" that is reasonably necessary to the normal operation of the business. Although the ADEA does not specifically prohibit an employer from asking an applicant's age or date of birth, the EEOC will take a close look at such questions to make sure that the inquiry was made for a lawful purpose.