In the context of the Americans with Disabilities Act of 1990 (ADA), an affirmative defense to an employer's obligation to provide reasonable accommodation to an employee with a disability.

The defense is allowed where an individual poses a threat to the health or safety of self or others (42 U.S.C. § 12113(b) and 29 C.F.R. § 1630.2(r)).

Employers can use this defense only if the individual poses a significant risk that cannot be reduced or eliminated by a reasonable accommodation.

Whether an individual poses a direct threat is based on reasonable medical judgment that may be based on current medical knowledge or the best available objective evidence. Factors include:

(29 C.F.R. § 1630.2(r).)

For more information, see Practice Note, Disability Accommodation Under the ADA: Direct Threat.