Kight on Cannabis: NIJ Researchers Get It Wrong on Cannabis Testing

recent article by researchers funded by the National Institute of Justice (NIJ) discusses cannabis testing. Unfortunately, however, the researchers misstate the law when it comes to hemp testing. The NIJ article primarily addresses the technical problem of ,”How [] labs [can] perform [] precise measurements quickly and easily when few labs [have] the personnel, instrumentation, and protocols to do so[.]” It proceeds to discuss two testing methods, gas chromatography-mass spectrometry (GC-MS) and direct analysis in real time-high-resolution mass spectrometry (DART-HRMS), that make quantitative determinations of whether a particular cannabis sample is legal hemp or illegal marijuana. My article is not about these particular methods. Rather, it is about the misstatement of law upon which the article is founded. Specifically, the article conflates tetrahydrocannabinolic acid (THCa) with delta-9 THC:

THC refers to Δ9-tetrahydrocannabinol, which is the major psychoactive component in cannabis. THCA is tetrahydrocannabinolic acid, and it is the most abundant non-psychoactive cannabinoid in cannabis. Here, total THC refers to Δ9-tetrahydrocannabinol plus THCA. In scientific terms, to find the “Δ-9 tetrahydrocannabinol concentration … on a dry weight basis” as stated in the statute, it is necessary to consider both the Δ9-THC concentration as well as the concentration of THCA.

This is an incorrect statement of the law. The 2018 Farm Bill defines “hemp” solely by reference to its delta-9 THC concentrations:

The term “hemp” means the plant Cannabis sativa L. and any part of that plant, including the seeds thereof and all derivatives, extracts, cannabinoids, isomers, acids, salts, and salts of isomers, whether growing or not, with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis.

The NIJ position appears to come from a June 9, 2023, response letter by the DEA to a request for the control status of several compounds, including delta-9 THCA. I address the DEA’s letter in detail in an article you can read by clicking here. In that letter, the DEA states: “[C]annabinoids that are extracted from the cannabis plant and that have a delta-9 THC concentration of not more than 0.3% on a dry weight basis meet the definition of ‘hemp’.” Notably, the DEA also addresses the control status of delta-9 THCA, stating:

In regards to delta-9-THCA, Congress has directed that, when determining whether a substance constitutes hemp, delta-9 THC concentration is to be tested “using post-decarboxylation or other similarly reliable methods.” 7 USC § 1639p(a)(2)(A)(ii); 7 USC § 1639q(a)(2)(B). The “decarboxylation” process converts delta-9 THCA to delta-9 THC. Thus, for the purposes of enforcing the hemp definition, the delta-9 THC level must account for any delta-9-THCA in a substance…. Accordingly, cannabis derived delta-9 THCA does not meet the definition of hemp under the CSA because upon conversion for identification purposes as required by Congress, it is equivalent to delta-9 THC.”[2] (emphasis added)

In this portion of the letter, and where the NIJ researchers go astray, is that the DEA is clearly referring to hemp that has not been harvested. This is because, while federal law requires the use of a post-decarboxylation testing method prior to harvesting hemp, a post-decarboxylation test does not apply to post-production hemp for the purposes of determining its control status. In fact, a post-decarboxylation testing method is inappropriate for determining the control status of harvested hemp and its derivatives, cannabinoids, and acids for the reason that it creates the molecule it is measuring. In most cases, it literally converts lawful hemp into illegal marijuana.

There are at least three reasons why using a “post-decarboxylation” testing method and using the “total THC” calculation to determine compliance for harvested hemp is a misapplication of the law.


The two statutes cited by the DEA in its letter, and upon which the NIJ researchers presumably rely, are the only two places in the Agriculture Improvement Act of 2018, commonly known as the “2018 Farm Bill”, that the term “post decarboxylation” appears. They both apply solely to hemp “production”.

In the first statutory provision, 7 USC § 1639p(a)(2)(A)(ii), Congress sets forth the criteria that Indian tribes and states must comply with in order to “have primary regulatory authority over the production of hemp” within their jurisdictions. The second statutory provision, 7 USC § 1639q(a)(2)(B), is similar in that it sets forth the criteria that the USDA must use to “monitor and regulate [hemp] production” in states that do not have an approved hemp plan and thus do not have primary authority over hemp production within their jurisdictions.

The key word in the above provisions is “production”. In the context of hemp, “production” is a legal term of art. Under 7 CFR § 990.1, to “produce” means: “To grow hemp plants for market, or for cultivation for market, in the United States.” Additionally, 7 CFR § 718.2 defines a “producer” as “an owner, operator, landlord, tenant, or sharecropper, who shares in the risk of producing a crop and who is entitled to share in the crop available for marketing from the farm, or would have shared had the crop been produced. A producer includes a grower of hybrid seed.” To produce hemp means to grow it.

Since the post-decarboxylation test clearly applies to producers, the DEA and the NIJ researchers are correct with respect to hemp that has not been harvested when they state that for the purposes of enforcing the hemp definition, the delta-9 THC level must account for any delta-9-THCA. However, once the pre-harvested hemp has accounted for delta-9 THCA and passed the required post-decarboxylation test, it may be harvested and no further tests are required. Further, as discussed above, the DEA has confirmed that, “the only thing that is a controlled substance is delta-9 THC greater than 0.3% on a dry-weight basis.


Additionally, the legal definition of “hemp” includes its “acids”. All cannabinoids in their acidic forms contain a carboxylic acid group that degrades (i.e., converts) to a different compound when subjected to a “post decarboxylation” testing method.[1] In other words, using a post-decarboxylation method to test harvested hemp degrades the pertinent acids in the hemp plant, rendering the term “acids” superfluous. Whenever possible, a statute should be construed so that effect is given to all its provisions, so that no part will be inoperative or superfluous, void or insignificant.[2] For this reason any interpretation of the 2018 Farm Bill that would require a post-decarboxylation test for harvested hemp renders the term “acids” superfluous and is thus contrary to the plain language of the statute.


Finally, it is clear that Congress did not intend for a “total THC” calculation to determine the legal status of harvested hemp. In defining “hemp”, it would have been easy for Congress to use the term “tetrahydrocannabinols” or “total THC” instead of “delta-9 THC”. This is made clear by the fact that the Pingree hemp bill uses the term “total THC” to define hemp. Had Congress intended for “delta-9 THC” to mean “total THC” there would be no reason for the Pingree bill to spell this out. (As an aside, the hemp industry should not support the Pingree hemp bill for this reason.)

In short, it is accurate to state that a hemp producer must use a “post-decarboxylation” testing method, which takes into account both delta-9 THC and THCa, to determine whether the producer’s hemp crop is compliant and can be harvested. Once that test is completed, the hemp crop may be harvested. Thereafter, with respect to harvested cannabis material, the Farm Bill is clear that the sole statutory metric for distinguishing between hemp and marijuana is the concentration of delta-9 THC, not “total THC”. Applying a “post-decarboxylation” method to harvested cannabis material improperly conflates the statutory provisions that solely pertain to hemp production with the legal definition of “hemp”. Had Congress intended for “total THC” to be part of the legal definition of “hemp” it would have said so. Finally, using a “post decarboxylation” method renders the term “acids” in the definition of hemp superfluous.

THCa hemp is legal “hemp” provided that its delta-9 THC levels do not exceed 0.3% by dry weight. It is is providing a crucial foothold for hemp farmers, small hemp businesses, and the cannabis industry at large to engage on an even playing field in the rapidly expanding US and global cannabis industry. Using the proper methodology to test for hemp compliance is critical to preserve the future of hemp.


[1] I confidentially asked two well-known and respected cannabis laboratory scientists about acidic cannabinoids and decarboxylation. One scientist’s response was: “I would be comfortable saying I do not suspect that any cannabinoid in an acid form that would be standardly tested for survives the conditions required for GCMS [gas chromatography mass spectrometry].” GCMS is a “post-decarboxylation” testing method. The other scientist had a similar response.

[2] Hibbs v. Winn, 542 U.S. 88, 101 (2004) (quoted in Corley v. United States, 556 U.S. 303, 314 (2009)); Astoria Federal Savings & Loan Ass’n v. Solimino, 501 U.S. 104, 112 (1991). See also, Bailey v. United States, 516 U.S. 137, 146 (1995) (“We assume that Congress used two terms because it intended each term to have a particular, nonsuperfluous meaning.”) (rejecting interpretation that would have made “uses” and “carries” redundant in statute penalizing using or carrying a firearm in commission of offense).

NOTE: This article is commentary. It is not intended to be legal advice and should not be construed as such. 

February 13, 2024

Rod Kight, Cannabis industry attorney








Rod Kight is an international cannabis lawyer. He represents businesses throughout the cannabis industry. Additionally, Rod speaks at cannabis conferences, drafts and presents legislation to foreign governments, is regularly quoted on cannabis matters in the media, and is the editor of the Kight on Cannabis legal blog, which discusses legal issues affecting the cannabis industry. You can contact him by clicking here



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