The term “employer” means a person engaged in an industry affecting commerce who has 15 or more employees for each working day in each of 20 or more calendar weeks in the current or preceding calendar year, and any agent of such person, except that, for two years following the effective date of this subchapter, an employer means a person engaged in an industry affecting commerce who has 25 or more employees for each working day in each of 20 or more calendar weeks in the current or preceding year, and any agent of such person.
The term “illegal use of drugs” means the use of drugs, the possession or distribution of which is unlawful under the Controlled Substances Act [21 U.S.C. 801 et seq.]. Such term does not include the use of a drug taken under supervision by a licensed health care professional, or other uses authorized by the Controlled Substances Act or other provisions of Federal law.
The term “qualified individual” means an individual who, with or without reasonable accommodation, can perform the essential functions of the employment position that such individual holds or desires. For the purposes of this subchapter, consideration shall be given to the employer’s judgment as to what functions of a job are essential, and if an employer has prepared a written description before advertising or interviewing applicants for the job, this description shall be considered evidence of the essential functions of the job.
The term “undue hardship” means an action requiring significant difficulty or expense, when considered in light of the factors set forth in subparagraph (B).