A version of this article appeared August 20, 2013, on page A6 in the U.S. edition of The Wall Street Journal.
Under Colorado’s new recreational-marijuana law, all retail pot products—from joints to laced brownies—will have to be labeled according to their potency starting next January.
But pot growers are running into a hurdle: There are no state or industry standards to test marijuana for tetrahydrocannabinol, or THC, the substance mainly responsible for its high-inducing properties.
The labels are intended to inform consumers on the nature of the product they are buying, not unlike alcohol-content labels on beer or wine. But current test results are haphazard, owners of medical-marijuana dispensaries complain, with the same marijuana receiving different marks depending on where it was analyzed.
Laboratory owners acknowledge results vary due to differing methodologies and advise growers not to compare ratings from different labs.
“The standard margin of error is like 25%,” said Evan Anderson, who has used several labs to test the medical marijuana he sells at his Boulder, Colo., dispensary, 14er Holistics. “That’s unacceptable in any kind of scientific setting.”
The uncertain testing standards underscore the challenge facing Colorado as well as Washington, where voters also approved recreational marijuana for anyone 21 and over last year, as state officials race to develop regulations to police a complicated new legal pot industry that is the first of its kind in the U.S. The states are operating under a legal cloud because the measures flout federal law prohibiting sale and possession of the substance.
For now, all state officials have to go on are the existing laws and standards that govern medical marijuana, which is legal in 20 states including Colorado and Washington, as well as in the District of Columbia.
But officials in both states have to develop frameworks before recreational-pot entrepreneurs can begin applying for the necessary licenses this fall and begin selling to customers in January.
A spokeswoman for the Colorado Department of Revenue said officials are still crafting testing rules. Beginning Tuesday, the agency will be holding public hearings to discuss specific proposals that include everything from lab-technician qualifications to how to dispose of tested samples.
Uwe Christians, who serves on a government-assembled working group on testing regulations, said cannabis labs should produce accurate results if the proposed rules are adopted.
It can take six to nine months to set up a reliable lab, according to Mr. Christians, who runs a drug-testing lab at the University of Colorado, Denver.
“Writing good standard operating procedures is very, very time-consuming,” he said.
The Washington State Liquor Control Board, which regulates marijuana, was scheduled last week to adopt rules for the recreational-marijuana industry, including how labs should be run, but pushed back its timeline to October to incorporate public input.
Brian Smith, a spokesman for the agency, said the rule-making process shouldn’t delay labs from setting up. “Our requirements are basic, which most any lab should already be following,” he said.
Sorting out testing is particularly difficult because there is little academic or commercial research, given that marijuana remains illegal under federal law. Even labs with government permission to study cannabis are forbidden to work with samples from states that have legalized pot such as Colorado and Washington, said Mahmoud ElSohly, who runs one such outfit at the University of Mississippi.
So, commercial pot labs have cobbled together their own system based on techniques and methods developed by Mr. ElSohly’s lab and others to chemically analyze marijuana seized by law enforcement, or to test other herbs such as St. John’s wort or chamomile. Testing a sample usually runs at about $50.
“Every lab at this point has a ‘six months in the garage’ story,” said Ian Barringer, owner of Rm3 Labs in Boulder, Colo., referring to months of effort spent refining methods. Mr. Barringer, who warns clients via his website that results aren’t comparable with those of other labs, said the only way to standardize testing is to do more of it, which won’t happen until labeling requirements kick in.
Klaas Hesselink, owner of Cannatest on Washington’s Bainbridge Island, got into the testing industry because as a chef, he was having trouble baking consistent marijuana-infused brownies for medicinal use.
He said he is now happy with testing protocol he found in his native Netherlands after coming up empty-handed in his U.S. search. But he added that to ensure industrywide accuracy, cannabis labs need third-party supervision.
Colorado and Washington will require lab certification.
“It’s the wild world of testing,” Mr. Hesselink said. “Without oversight, who’s going to do everything the right way?”
The American Herbal Pharmacopoeia, a Scotts Valley, Calif., nonprofit that creates guidelines for herbal testing for products used in dietary supplements and teas, is working on a set of standards for cannabis cited as a reference in Washington’s proposed rules. Roy Upton, the group’s executive director, said he hoped it could help laboratory results become comparable.
Mr. Anderson, the Boulder dispensary owner, said he would do the required testing, but is also sticking with the only method that has rendered accurate results so far: Smoking his pot himself.
“The personal tests are far more valuable in selling the product than anything that we’ve gotten from the lab,” he said.
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A version of this article appeared August 20, 2013, on page A6 in the U.S. edition of The Wall Street Journal