For the most part, employers are free to require job applicants to take a drug test. (For more, see Can Employers Require Applicants to Pass a Drug Test?) However, some state laws limit an employer's right to test those who are already employed.
Most private employers aren't required to test for drug use. There are a couple of exceptions, however. First, employers in the transportation industry and other safety-sensitive fields that are regulated by certain federal agencies, including the Federal Aviation Administration and the Federal Highway Administration, may be required to test at least some employees for drug use. Also, some employers that contract with the Department of Defense, NASA, and other government agencies may be required to test.
Second, some states have drug-free workplace laws, which provide incentives to employers who take certain steps to combat substance abuse. Often, these laws allow employers to qualify for a discount on their workers' compensation premiums if they meet the requirements, which might include drug testing. Employers in these states may have to adopt a drug testing program if they want to get the discount.
Otherwise, however, drug testing isn't generally required.
Employers may drug test current employees only if their state's law allows it. Not every state allows employers to conduct drug tests in every situation. For example, some states prohibit or limit an employer's use of random drug tests. A state's law may require the employer to have a reasonable suspicion of drug use (for example, because the employee has been involved in an accident or had a positive test result in the past) before testing.
Some states require employers to follow procedures intended to protect employee rights. For example, employers may have to adopt a written policy explaining their drug testing program; give employees who test positive an opportunity to appeal and have a retest; or give employees who test positive an opportunity to seek treatment.
Here are a few things to watch out for if you are asked to take a drug test:
If you're concerned about the legality of your employer's drug testing program, or if you believe you've been unfairly disciplined or fired following a drug test, you might consider talking to an employment attorney. The laws of drug testing vary from state to state. An experienced lawyer can assess your employer's testing process and help you decide how to proceed.