Most private employers have the right to test for a wide variety of substances. However, it is important that employers familiarize themselves with the various state and federal regulations that may apply to their business or organization before designing a drug-testing policy. The majority of employers across the US are NOT required to test, and many state and local governments have statutes that limit or prohibit workplace testing unless it is required by state or federal regulations for certain jobs. Drug-testing policies protect both employees and employers. It is important for employers to note that drug testing without a drug-testing policy -- even if an employee is suspected of having a substance abuse problem -- exposes them to a number of significant liability and legal vulnerabilities.
The information on this page is meant to provide a general overview of the law. The laws in your state and/or city may deviate significantly from those described here. If you have specific questions related to your situation you should speak with a local attorney.