Colorado cannabis employment and drug testing law
No statutory protection. The Colorado Supreme Court held the lawful off-duty activities statute does not protect cannabis use, because it remains unlawful under federal law. Status: No statutory protection — State law expressly lets employers refuse to hire or discipline over cannabis use.
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Key Takeaways
- Status: No statutory protection — State law expressly lets employers refuse to hire or discipline over cannabis use.
- Main source: Coats v. Dish Network, 2015 CO 44.
- Federal testing rules (DOT and federal workplace programs) apply regardless of state law.
Is there any protection?
- Colorado has a general “lawful activities” statute (C.R.S. § 24-34-402.5) that bars firing an employee for lawful activity off the premises during nonworking hours. In Coats v. Dish Network (2015 CO 44), the Colorado Supreme Court held that “lawful” there means lawful under both state and federal law.
- Because cannabis use is prohibited by the federal Controlled Substances Act, the court held that state-licensed medical marijuana use at home during nonworking hours is not protected by that statute.
What employers may do
- The case arose after an employee who was a registered medical patient tested positive on a random test and was terminated under the company’s drug policy; the court affirmed dismissal of his claim (Coats).
Drug testing rules
- We found no Colorado statute that restricts private-employer cannabis testing in the sources reviewed; employer policy generally governs.
Notes and history
- This page relies on the state supreme court opinion. Check for any later legislation before relying on it.
Federal law and testing
Federal rules still apply. Under the U.S. DOT’s testing rules, a Medical Review Officer must not verify a test as negative because a physician recommended a Schedule I drug under a state “medical marijuana” law, and must not accept use of hemp or other non-prescription marijuana-related products as an explanation (49 CFR § 40.151(e)–(f)). That covers safety-sensitive transportation workers regardless of state law.
Federal workplace drug testing programs follow HHS Mandatory Guidelines, which set the cannabis testing panel and cutoffs for urine and oral fluid (Federal Register, March 13, 2026). Most state protections above include an exception where federal law, a federal contract, or federal funding requires otherwise.
For how long cannabis can show up on each test type, see our drug testing guide and the detection window explainer.
Common questions
Can you be fired for using cannabis in Colorado?
Generally, yes. Based on Coats v. Dish Network, 2015 CO 44, Colorado law does not protect employees from adverse action over cannabis use, so an employer’s drug policy usually controls.
Can Colorado employers still drug test for THC?
Yes. Coats v. Dish Network, 2015 CO 44 does not ban drug testing; it shapes what an employer may do with the results. Federally required tests, such as DOT-regulated jobs, are unaffected by state law.
Does Colorado law protect CDL drivers or federal workers?
No state law overrides federal testing rules. DOT-regulated employees remain subject to federal cannabis testing, and a state medical recommendation is not an accepted explanation for a positive result.
Sources
- government Coats v. Dish Network, LLC, 2015 CO 44 (Colorado Supreme Court opinion, via Justia) ↗ accessed 2026-10-03
- government eCFR, 49 CFR § 40.151 — What are MROs prohibited from doing as part of the verification process? (U.S. DOT) ↗ accessed 2026-10-03
- government Federal Register, Mandatory Guidelines for Federal Workplace Drug Testing Programs: Authorized Testing Panels (March 13, 2026) ↗ accessed 2026-10-03