In 1988, the Federal Government enacted the Employee Polygraph Protection Act of 1988 (EPPA). This law superceded Washington State law and prohibited the use of polygraph by private employers in all but a few exceptions. The primary use of the polygraph by private employers is during their internal investigations into the theft of company property, money, goods and/or services.
The copy of the Employee Polygraph Protection Act of 1988 (EPPA) is available through the U.S. Department of Labor. This law will dictate your use of the polygraph during your investigations. It will explain the uses of the polygraph that are still acceptable and the details of your ability to use the polygraph during your internal investigations. You should have your attorney examine this law carefully and make a decision whether your intended use of the polygraph is exempted from the law.
A complete copy of the law is available on the internet at: EPPA Law
This law makes the use of the polygraph much more restrictive than in the past, but possible when certain conditions are met.