[MCOH-EH] Marijuana... again

Fung, Fred ffung at thezenith.com
Wed Feb 2 13:14:49 PST 2022

I hesitated but decided to contribute my opinion as a certified medical toxicologist and licensed attorney on the topic about marijuana.
Dr. Swift is correct from med-legal perspective. For those who manage both employee health AND work comp would be in most difficult situation because they belong to different spheres of the "law". Employee health is Employment Law (relatively uniform in various jurisdictions) whereas work comp is Insurance Law (specific Work Comp law is jurisdictional). They should be partitioned due to state privacy laws and federal HIPAA. Yet, most Employee Occupational Health Professionals need to manage both.

With regards to blood delta 9 THC and intoxication, my opinion is that blood (whole, serum, plasma) THC over 5 ng/ml would be reasonable probable intoxication. THC over 2 ng/ml is possible intoxication. Ratio of carboxy-THC and delta 9 THC can also provide time frame of how recently a person imbibed the intoxicating THC. Metabolites of THC do not induce intoxication. Some board certified med tox may disagree but I have had 90% success in persuading judges "scientifically reasonably probable" of intoxication provided that "proximate causation" of injury/incident is satisfied. Legally, proximate causation is a more difficult burden to prove than medical impairment based on blood THC over 5 ng/ml around the time of incident.
Urine THC regardless of how high may not be used to implicate intoxication in most jurisdictions.

With regards to urine drug screening (UDS) for employment purposes, it is almost useless to decline employment solely due to positive UDS if legally challenged. As we know, THC metabolites may have a long half life up to weeks. Safety sensitive occupation is a word of art that should be defined by institution's employment law attorney prior to job posting. MRO functions are mostly administrative so clinical decisions still fall on Employee/Occupational Health professionals. Fitness for duty would be another difficult employment law related topic if the employee is placed on leave for drug related issues if UDS is positive, and at what threshold is unclear.

Bottom-line, as EOH professionals, we need to work closely with attorneys of the institution on both employment law and work comp law when marijuana/cannabis UDS is involved. Cheers!

Fred Fung, MD, JD, Esq.


From: MCOH-EH <mcoh-eh-bounces at mylist.net> On Behalf Of Swift, Melanie D., M.D., M.P.H. via MCOH-EH
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Cc: Swift, Melanie D., M.D., M.P.H. <Swift.Melanie at mayo.edu>; Thorne, Craig <Craig.Thorne at YNHH.ORG>
Subject: Re: [MCOH-EH] Marijuana... again

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Well, here we are in the Brave New World where pretty soon recreational marijuana will just be legal everywhere. I am not at all sure this is a good thing, but that's my crotchety old fart side I suppose. We aren't there yet, but it does seem the tide has turned and we're headed there. So marijuana will be, like alcohol, a legal substance that is addictive and potentially impairing, and still has implications for safety-sensitive jobs. I think as we see more states legalize recreational marijuana, we'll need to shift to treating it more like alcohol for work-relatd testing purposes. It's not illegal to use alcohol when you are off duty, or before you start a job, but you cannot be impaired by it. The trouble with THC is (and that would be a great name for a musical - The Trouble with THC) that unlike alcohol we don't have a laboratory test that correlates with impairment and clearance of metabolite is days to weeks (or even months sometimes) compared to hours.

Setting aside regulated testing for a moment, and just thinking about healthcare workers: I think we may see more employers remove it from their preemployment panel for HCP in states with legal recreational marijuana. But it really should remain on the panel for reasonable suspicion, return to duty, and follow up tests. If you have evidence of impairment, or you have a substance use disorder and are under a monitoring agreement that requires abstinence, it's still important to test for THC metabolites. If positive, we have to assume impairment for reasonable suspicion tests. If positive on a RTD test one could do serial testing with quantitative values to confirm they are not continuing to use. Clearance can take a very long time, but if they are using their level should not be dropping consistently.

Just my opinion,


From: MCOH-EH <mcoh-eh-bounces at mylist.net<mailto:mcoh-eh-bounces at mylist.net>> On Behalf Of Thorne, Craig via MCOH-EH
Sent: Monday, January 31, 2022 12:29 PM
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Cc: Thorne, Craig <Craig.Thorne at YNHH.ORG<mailto:Craig.Thorne at YNHH.ORG>>
Subject: [EXTERNAL] [MCOH-EH] Marijuana... again

Good afternoon All,

So, with marijuana now legal in the state of CT, hospitals are looking to each other to determine if they should accept recreational marijuana use as a legitimate explanation for a positive THC test. The law gives some leeway to health care organizations to make their own decision about this - at least for now.

Another topic of discussion is whether we should find a reasonable HCW panel that does not include marijuana.

Any thoughts from you pioneers out there that you want to share would be greatly appreciated.

Thank you,


Craig D. Thorne, M.D., MPH, MBA
Chief Medical Director, Occupational Medicine and Business Health Services
(203) 687-5281 mobile

"Feeling gratitude and not expressing it is like wrapping a present and not giving it".
-William Arthur Ward, American writer and thought leader
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