Toyota Motor Manufacturing, Kentucky, Inc. v. Williams, was a case in which the Supreme Court interpreted the meaning of the phrase "substantially impairs" as used in the Americans with Disabilities Act. It reversed a Sixth Court of Appeals decision to grant a partial summary judgment in favor of the respondent, Ella Williams, that qualified her inability to perform manual job-related tasks as a disability. The Court held that the "major life activity" definition in evaluating the performance of manual tasks focuses the inquiry on whether Williams was unable to perform a range of tasks central to most people in carrying out the activities of daily living. The issue is not whether Williams was unable to perform her specific job tasks. Therefore, the determination of whether an impairment rises to the level of a disability is not limited to activities in the workplace solely, but rather to manual tasks in life in general. When the Supreme Court applied this standard, it found that the Court of Appeals had incorrectly determined the presence of a disability because it relied solely on her inability to perform specific manual work tasks, which was insufficient in proving the presence of a disability. The Court of Appeals should have taken into account the evidence presented that Williams retained the ability to do personal tasks and household chores, such activities being the nature of tasks most people do in their daily lives, and placed too much emphasis on her job disability. Since the evidence showed that Williams was performing normal daily tasks, it ruled that the Court of Appeals erred when it found that Williams was disabled. This ruling is now, however, no longer good law—it was invalidated by the ADAAA. In fact, Congress explicitly cited Toyota v. Williams in the text of the ADAAA itself as one of its driving influences for passing the ADAAA.
Once you have been hired and started work, your employer cannot require that you take a medical examination or ask questions about your disability unless they are related to your job and necessary for the conduct of your employer's business. Your employer may conduct voluntary medical examinations that are part of an employee health program, and may provide medical information required by State workers' compensation laws to the agencies that administer such laws.