The School Board of Nassau County, Florida v. Arline case in 1986 was a landmark decision by the US Supreme Court that expanded the definition of disability under Section 504 of the Rehabilitation Act. The case involved Gene Arline, an elementary school teacher who had been fired because she suffered from tuberculosis. The court ruled in favor of Arline stating that her dismissal constituted discrimination based on her health condition and thus violated federal law prohibiting such discrimination against individuals with disabilities. This ruling established precedent for considering contagious diseases as impairments which could limit major life activities and therefore qualify as disabilities under federal law.

In the dissenting opinion for School Board of Nassau County, Florida v. Arline, Justice Powell argued that the majority's decision to classify contagious diseases as a handicap under Section 504 of the Rehabilitation Act was an overreach. He contended that this interpretation went beyond what Congress had intended when it passed the legislation and could have far-reaching consequences for public health policy. Furthermore, he expressed concern about potential implications on employers who might be forced to retain employees with infectious diseases in positions where they could pose risks to others' health or safety. He also noted that such broad interpretation may lead to absurd results like protecting individuals engaged in illegal drug use simply because their addiction can be classified as a disease.