29 C.F.R. § 541.706

(a) An exempt employee will not lose the exemption by performing work of a normally nonexempt nature because of the existence of an emergency. Thus, when emergencies arise that threaten the safety of employees, a cessation of operations or serious damage to the employer's property, any work performed in an effort to prevent such results is considered exempt work.

(b) An “emergency” does not include occurrences that are not beyond control or for which the employer can reasonably provide in the normal course of business. Emergencies generally occur only rarely, and are events that the employer cannot reasonably anticipate.

(c) The following examples illustrate the distinction between emergency work considered exempt work and routine work that is not exempt work:

(1) A mine superintendent who pitches in after an explosion and digs out workers who are trapped in the mine is still a bona fide executive.

(2) Assisting nonexempt employees with their work during periods of heavy workload or to handle rush orders is not exempt work.

(3) Replacing a nonexempt employee during the first day or partial day of an illness may be considered exempt emergency work depending on factors such as the size of the establishment and of the executive's department, the nature of the industry, the consequences that would flow from the failure to replace the ailing employee immediately, and the feasibility of filling the employee's place promptly.

(4) Regular repair and cleaning of equipment is not emergency work, even when necessary to prevent fire or explosion; however, repairing equipment may be emergency work if the breakdown of or damage to the equipment was caused by accident or carelessness that the employer could not reasonably anticipate.