NOVA Legal Beat: How do I Know What an ‘Essential Function’ is?

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Editor’s Note: This sponsored column is written by Mathew B. Tully of Tully Rinckey PLLC, an Arlington firm that specializes in federal employment and labor law, security clearance proceedings, and military law.

Q. I have a disability, and my employer is trying to remove me because it claims I cannot perform the “essential functions” of my position. How do you tell the difference between essential and non-essential functions?

A. Under the Americans with Disabilities Act (ADA), employers are required to provide disabled employees with reasonable accommodations, such as a part-time schedule or reassignment to a vacant position, so long as they are able to perform their position’s essential functions. In addition to being able to perform these essential functions either with or without a reasonable accommodation, employees seeking ADA protection must have a “physical or mental impairment that substantially limits one or more major life activities.”

What qualifies as an “essential function” is largely a matter left to the discretion of employers. The ADA states, “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.” But that does not mean an employer’s assertion that something is a position’s essential function is not open to debate.

Equal Employment Opportunity Commission (EEOC) regulation states that essential functions include “fundamental job duties of the employment position the individual with a disability holds or desires” and exclude “marginal functions of the position.”

When trying to determine whether a particular task qualifies as a position’s essential function, employees should ask whether the position “exists… to perform that function;” whether there is a “limited number of employees available among whom the performance of that job function can be distributed;” and whether the function is “highly specialized so that the incumbent in the position is hired for his or her expertise or ability to perform the particular function,” according to the regulation.

Evidence that courts will consider when determining whether a function is essential include written job descriptions, time spent performing the function, collective bargaining agreement terms, consequences of the function not being performed, and the work experience of people who previously held the position or those who hold similar positions, according to the EEOC regulation. It should be noted that job descriptions in advertisements may not alone be sufficient to dispute an employer’s claim that a function is essential.

For example, Thompson v. Heiner’s Bakery (2012), involved a delivery truck driver who, due to his heart defibrillator, was not able to obtain Department of Transportation (DOT) medical certification needed to operate any of his employer’s carrying-capacity-upgraded delivery trucks. The employee requested — and the employer refused — an accommodation in the form of a suspension of the delivery truck fleet upgrade and allowing him to drive a non-upgraded vehicle. The employee claimed driving a higher capacity truck was not an essential function for his position, and to support this claim he presented as evidence an employer truck driver job advertisement was silent on the subjects of gross vehicle weight ratings or DOT medical certification.

The U.S. District Court for the Western District of Virginia, however, found the employee was not able to perform his position’s essential functions, noting that “[a]s business necessity evolves, so too can a job’s essential functions.” An employer “is no more obligated to pause its evolving business model in order to retain a current employee than it is to rewind its current business model to hire a new employee.”

Employees who believe an employer has wrongfully denied them a reasonable accommodation should immediately consult with an experienced employment law attorney. Employers should also consult with an attorney who can help them decide whether a position’s functions are essential or not essential and what kind of accommodation, if any, should be provided.

Mathew B. Tully is the founding partner of Tully Rinckey PLLC. Located in Arlington, Va. and Washington, D.C., Tully Rinckey PLLC’s attorneys practice federal employment law, military law, and security clearance representation. To speak with an attorney, call 703-525-4700 or to learn more visit 

The views and opinions expressed in the column are those of the author and do not necessarily reflect the views of

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