Whenever age becomes a factor, instead of skills and qualifications, in determining a person's job status with a company, it's known as age discrimination. For example, sometimes employers assume that older workers are more expensive to train and possess fewer up-to-date skills than younger workers and, as a result, terminate or refuse to hire them based on those assumptions. In order to protect older workers from such unfair assumptions and to ensure that they receive equal opportunity in the workplace, Congress enacted the Age Discrimination in Employment Act, also known as ADEA (A-D-E-A). Under the ADEA, it's unlawful for employers to discharge, refuse to hire, or discriminate on the basis of age in regards to compensation, terms, and conditions of employment. The ADEA applies to all employers with at least 20 employees and protects both employees and job applicants who are 40 years old or older. Keep in mind that while you have to be aged 40 or older to file a claim under the ADEA, you may still file a discrimination claim if an employer replaced you or hired someone who was also older than 40. For example, suppose you're a 55-year-old employee who was fired and replaced with a 42-year-old worker. You may still have a discrimination claim even though your employer hired someone over 40 to replace you. Remember also that many states have passed their own age discrimination laws, some stronger than the federal law. For example, some states provide protections against age discrimination for all employees regardless of age, while other states may have a lower age protection. As with most laws, there are several exceptions to ADEA. State employees, police, and fire personnel, for example, generally aren't protected under the Act. Probably one of the biggest exceptions to the federal age discrimination law is made when age is an essential part of a particular job. Known as 'bona fide occupational qualification', or BFOQ (B-F-O-Q), this exception allows employers to set age limits on a particular job if they can prove that the limit is necessary because a worker's ability to perform the particular job adequately does, in fact, diminish after the age limit is reached.