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An employer who is accused of disparate treatment (discriminating against a member of a protected class) can avoid liability by using the bona fide occupational qualification defense (BFOQ) or a Business Necessity defense. The use of the BFOQ defense is restricted, however, and can be asserted only when the employer discriminates against religion, sex, pregnancy, or national origin. It does not apply to race claims. Examples: mandatory retirement ages for bus drivers (disparate impact on those over the age of 40), and airline pilots for safety reasons; in advertising, a manufacturer of men's clothing may lawfully advertise for male models (disparate impact on women). Religious belief may also be considered a BFOQ; for example, a religious school may lawfully require that members of its faculty be members of that denomination (disparate impact on other religions).
The business necessity defense: When an employer's facially neutral practice disproportionately harms minority or women workers, the workers may sue for disparate impact discrimination under Title VII. An employer whose practice is found to have such an impact may avoid liability by proving that the challenged discriminatory practice is required by "business necessity."
This defense is not restricted. It applies to disparate impact against all protected groups.
An example of a business necessity defense which was upheld by the 11th circuit court recently, in a disability claim, was when a man with a hearing impairment filed suit claiming discrimination under the Americans with Disabilities Act (ADA) because the U.S. Marshal required hearing to get the job. The Marshal used the business necessity defense as the reason he was not hired. The plaintiff argued that he could wear a hearing aid as an accommodation. The court held for the U.S. Marshal, because they successfully argued that wearing a hearing aid as an accommodation would not work because the hearing aid could fall out, or malfunction, causing safety risks for their customers, therefore, it was a "business necessity" that anyone in this job must be able to hear without the use of a hearing aid. Another example is requiring a college degree in computer science for a job, due to the need for a minimum level of training to understand how to program computers or use software. Having a college degree as a job requirement may have a disparate impact on minorities, but is a business necessity for an employer who provides computer programming training or service to companies they sell their software to.