A policy must address what is prohibited, when testing occurs, and how the results are used.
Prohibited conduct. Use, possession, distribution and impairment at work or on company property, defined clearly, with the distinction between impairment and the presence of a metabolite stated.
Testing categories. Pre-employment, reasonable suspicion, post-accident, random for safety-sensitive positions where permitted, and return to duty.
Reasonable suspicion based on documented objective observations by trained supervisors, recorded on a form at the time.
Post-accident testing tied to a reasonable possibility that impairment contributed, since blanket post-accident testing has been criticised as discouraging injury reporting.
Safety-sensitive designations by written criteria applied consistently.
Federally regulated positions where testing is mandatory and preempts state protections.
State protections for medical and recreational cannabis use, off-duty lawful conduct, and prescribed medication, which vary widely and constrain what a national policy can do.
Accommodation. For employees in recovery and for lawfully prescribed medication, with confidentiality of medical information.
Chain of custody and confirmation testing through a certified laboratory, with a medical review officer.