In states that have legalized marijuana, employers are required to prove there is a connection between a positive drug test and actual impairment before adverse employment action can be taken. Therefore, it’s critical that you review your drug policy now to ensure compliance with any new regulations. How long marijuana impairment lasts is a critical point when choosing a drug testing method. Each method has its own window of detection, and some methods better correspond with marijuana’s actual window of impairment. So the question remains… is urine, oral fluid, or hair testing the best method for detecting marijuana?
The answer is… it depends. Many factors contribute to how easily an individual becomes impaired by marijuana and for how long they are impaired. The duration of impairment depends on the method of use (inhaling or ingesting), frequency of use, and the demands of the task being managed while intoxicated.
A recent study from the University of Sydney identified the window of impairment to be between 3-10 hours. According to this study, a typical length of impairment is about 4 hours, when low doses of THC are taken and simpler tasks are being done. This length of impairment can go up if high doses of THC are inhaled and more complex tasks, like driving, are needed.
That being said, current impairment is still challenging to infer based on repeated drug use. When trying to figure out which drug testing method to use, three attributes need to be examined.
- The method’s ability to detect recent drug use
- The method’s window of detection compared to marijuana’s method of detection
- The method’s ability to detect drugs other than marijuana
Choosing the right drug testing method can be tricky. In all 50 states, employers still have the right to prohibit workers from using marijuana at work or being impaired on the job (more on this in the next newsletter). Understanding marijuana impairment can help companies choose the drug testing method that best meets their needs. Blueline is here to help you. Our experts can help you find the drug testing method that helps protect your workforce and business assets while mitigating risk and liability.