Title I of the Americans with Disabilities Act (ADA) of 1990
prohibits private employers, state and local governments, employment agencies, and labor unions from discriminating against qualified individuals with disabilities in job application procedures, hiring, firing, advancement, compensation, job training, and other terms, conditions, and privileges of employment. The ADA covers employers with 15 or more employees, including state and local governments. The ADA's nondiscrimination standards also apply to federal sector employees under section 501 of the Rehabilitation Act, as amended, and it’s implementing rules.
A qualified employee or applicant with a disability is an individual who, with or without reasonable accommodations
can perform the essential functions of the job in question. Essential job functions are the fundamental job duties that the person must be capable of performing. Some reasons a function may be considered essential are: