(TMU) — Law enforcement in the United States has been advised to look for a “possible green coating” on the tongues of people who have recently smoked marijuana.
Despite having no scientific evidence of this phenomenon whatsoever, a training program used throughout the world is instructing officers to be on the look out. And as it turns out, they’ve used this marker during cases of possible DUI for decades.
Bradley Myerson, a defense attorney in the state of Vermont, explained:
“If someone is going to be convicted, it should be based on facts proven beyond a reasonable doubt. Green tongue has nothing to do with marijuana ingestion, let alone impairment.”
An investigation by the York Daily Record revealed that in at least 28 of 1,300 DUI cases analyzed, the phrases “green coating,” “green film,” and “green tint” were mentioned.
So far, courts in two states have expressed their doubts when it comes to the green tongue phenomenon.
The Washington Court of Appeals upheld a ruling to throw out a case in 2000 involving the observation of a green tongue by a state trooper. The officer used their observation of the person’s tongue as justification to search the vehicle.
Judge Elaine M. Houghton wrote that, even if a green tongue did indeed mean that a person had recently used marijuana, a lack of additional observations of marijuana use as well as the fact that a green tongue can be caused by numerous things showed there was actually a lack of reasonable suspicion.
Houghton went on to explain:
“Although we assume the officer’s assertion to be true for purposes of this opinion, we are nevertheless skeptical as to its accuracy. We find no case stating that recent marijuana usage leads to a green tongue.”
Back in 2004, the Utah Court of Appeals ruled that the state trooper who arrested a man using observations that included his having a green tongue was not enough to support probable cause. In that case, Judge William A. Thorne Jr. noted the state “presented nothing, no scientific studies and no case law or other authority, to support the reliability of the trooper’s concern.”
The judge also said the court was left “troubled” that the state trooper in question considered a green tongue to be “proof of marijuana use.”
So where did this national, if not international, phenomenon originate?
According to the York Daily Record, Nick Morrow knows. Morrow worked for the Los Angeles County Sheriff’s Department until the mid-90s as a certified drug-recognition expert and described himself as a “complete drug nerd.”
Morrow contends that a 1986 guide authored by Dr. Forest Tennant Jr. and titled Identifying the Marijuana User is the culprit. The book, which is dedicated to the California Highway Patrol, includes an image of a person with a green tongue.
Throughout his entire career, Morrow has only witnessed one case in which the green tongue phenomenon held true. “The guy was drinking green beer and smoking weed”—on St. Patrick’s Day.
Scott Harper, a West York defense attorney, describes the green tongue marker as “kind of junk science.” In fact, Harper recently argued in a DUI case that there exists “no evidence that a ‘green tongue’ is indicative of any specific degree of marijuana impairment.”
Harper says he’s “still waiting to see a green tongue someday.”
Erik Altieri, executive director of the National Organization for the Reform of Marijuana Laws (NORML) explained:
“The science behind marijuana consumption turning your tongue green is about as sound as the science behind the earth being flat or that lying makes your nose grow.”
Despite a lack of scientific evidence and multiple rulings that a green tongue doesn’t support probable cause, a Drug Recognition Expert Course instructor guide from 2018 reads “a greenish coating on the tongue has been documented in two peer‐reviewed articles.”
But in 2015, that same guide included a note stating, “Point out that there are no known studies that confirm Marijuana causing a green coating on the tongue.”
It turns out those two peer-reviewed articles are from 1998 and 2017, with the article from 1998 including the green tongue phenomenon simply because police officers were being taught it in the Drug Evaluation and Classification Program. It should also be noted that two of the five authors of the article worked in law enforcement at the time.
The 2017 article included data from a study in which police officers noted a “coating on the tongue” of a high percentage of people who had THC in their system. The study’s authors didn’t conclude if marijuana does indeed cause the coating on the tongue and didn’t comment on the color.
Nevertheless, Kyle Clark, national project manager of the Drug Evaluation and Classification Program for the International Association of Chiefs of Police, says the green tongue phenomenon is “common” and has been included in training manuals as far back as 1992.