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- Drug-Free Workplace Advisor

Please note: The Department of Labor ended the drug-free workplace program in 2010. Accordingly, it does not currently administer a “Workplace drug testing” advisory web page and is not responsible for the content of the linked sites.


Marijuana is a derivative of the cannabis sativa plant and is illegally used for its intoxicating effects and dreamy state of relaxation and euphoria. All forms of marijuana have negative physical and mental effects. The active ingredient in marijuana is Delta-9-Tetrahydrocannabinol, or THC.


Several regularly observed physical effects of marijuana include:

  • substantial increase in heart rate
  • bloodshot eyes
  • dry mouth and throat
  • increased appetite
  • chronic sore throat

Use of marijuana also has mental effects that may include:

  • impaired or reduced short-term memory and comprehension
  • altered sense of time
  • changed sensory perception--sight, smell, hearing, touch
  • reduced ability to perform tasks requiring concentration and coordination, such as driving a car

Research also shows that people do not retain knowledge when they are “high”. Motivation and cognition may be altered, making the acquisition of new information difficult. Marijuana also can produce paranoia and psychosis.


  • Emphysema-like symptoms
  • Respiratory track and sinus infections
  • Lowered immune system response

Because users often inhale the unfiltered smoke deeply and then hold it in their lungs as long as possible, marijuana is damaging to the lungs and pulmonary system. Marijuana smoke contains more cancer-causing agents than tobacco smoke.

Long-term users of marijuana may develop tolerance levels requiring more and more marijuana to achieve the same “high”. Prolonged use leads to dependence, and the drug can become the center of users’ lives.

THC also is contained in a prescription medication called Marinol that is prescribed for cancer patients who are suffering from severe nausea and loss of appetite. Some states have passed propositions to consider marijuana a medication that can be used with a physician’s recommendation.


  • Employees who fall under Federal guidelines such as the Department of Transportation’s testing regulations are prohibited from using marijuana in any form.
  • THC is stored in the body fat and is slowly released over time. Since it is retained in the fat, an employee can test positive many days after use.
  • Many employers also have work rules requiring the employee to disclose if he or she is taking any sedating medications that could impact his or her ability to work safely. This rule would apply even in states that have approved the medicinal use of marijuana.
  • The use of marijuana definitely would cause fitness-for-duty concerns.

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