Do I have to take a polygraph in a workplace investigation?


I work at a large warehouse store. Recently, we've had a string of thefts of laptops, tablets, and phones. We've always have some of these items go missing, but lately it has gotten a lot worse. According to our inventory tracking system, these items are disappearing before they even get on the shelves. Because of this, those of us who unload products and store them in the back area are under suspicion. Our manager has said that we will all have to take a polygraph test as part of the company's investigation. Is this legal?


Polygraphs (formerly called "lie detector tests") used to be more common, both in the workplace and in law enforcement. Once heralded as a foolproof technology to ferret out the truth, they are now seen in a more nuanced light. Science has shown that false positives (and negatives) are more frequent than once thought, especially if the person conducting the test and interpreting the responses is not carefully trained.

To limit an employer's ability to use polygraph testing, Congress passed the Employee Polygraph Protection Act (EPPA) in 1988. In most circumstances, the EPPA prohibits employers from requiring employees or applicants to take a polygraph. However, Congress carved out an exception for certain types of workplace investigations. An employer that is engaged in an ongoing investigation of economic loss or injury to the employer's business may require employees to take a polygraph test, as long as it follows a lengthy list of technical requirements. These include giving the employee extensive written notices before the test (including an exact list of all questions to be asked), observing a number of rules during the test, and providing the employee with a copy of the test results. The employer must also use a polygraph examiner who meets specific qualifications.

If your employer plans to rely on the ongoing investigation exception, it may ask you to take a polygraph only if all of the following requirements are met:

  • You had access to the property that is the subject of the investigation.
  • Your employer has a reasonable suspicion that you were involved in the incident or activity.
  • You receive a written statement regarding the incident and your employer's suspicion that you were involved.

It sounds like the spate of thefts might allow your employer to use the ongoing investigation exception in your case. However, your employer may polygraph you only if it has a reasonable suspicion you were involved, as noted above, and follows all of the EPPA's notice and procedural requirements. Even if your employer follows all the rules, it still may not take action against you based on the test results alone. Your employer must have some additional evidence of your guilt, other than the polygraph, to take disciplinary action against you.

As you can see, the EPPA includes so many restrictions and requirements that few employers bother to polygraph test employees. If yours does, and you have any question about the process or results, you should talk to an experienced employment lawyer.

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