Interim Hemp Rule: THC Testing

The USDA released its Interim Final Hemp Production Rule on October 29, 2019. The full 161-page document is available here. The public comment period will open once the regulations are published in the Federal Register. The interim rule will be effective for two years and then be replaced with a final rule.

States and Indiana Tribes can develop hemp regulation plans for USDA approval. But there are certain federal requirements that all hemp producers will have to satisfy: licensing requirements, records retention, THC testing, disposal of non-compliant plants, and procedures for handling violations. This article gives an overview of the THC sampling and testing requirements. We’ll post more articles in the days to come which will address other provisions in the regulation.

THC TESTING: A key point for anyone thinking about growing, transporting, buying, distributing, processing, or selling hemp: hemp plants with a THC level over 0.3% is considered marijuana. Thus, in states where marijuana is not already legal, “hot” hemp can get you into real trouble. The interim rule requires state plans to incorporate procedures to sample plants and test the THC level. Within 15 days before harvest, a law enforcement official or other representative designated by the state or Tribe must collect representative samples from the plant flowers for testing. If producers delay harvest beyond 15 days, the plant will likely have a higher THC level at harvest than the sample that is being tested. This requirement will yield the truest measurement of the THC level at the point of harvest. [The USDA is specifically seeking public comment on this 15-day testing window.] The samples must be delivered to a laboratory registered with the DEA for testing.

The rule includes scientific specifications for lab procedures to ensure accurate testing results. Samples must be tested using reliable analytical methods where the total THC concentration level reported accounts for the conversion of delta-9-tetrahydrocannabinolic acid (THCA) into THC. Testing methodologies currently meeting these requirements include those using gas or liquid chromatography with detection. The total THC, derived from the sum of the THC and THCA content, shall be determined and reported on a dry weight basis. 

The rules require that cannabis plants with a THC concentration over 0.3% on a dry weight basis must be disposed of in accordance with the approved state or tribal plan. Because this can cause a producer to lose all of her investment, the rule requires labs to calculate the measurement of uncertainty (like a margin of error) of its THC testing. The interim rule’s definition of “hemp” (as opposed to marijuana) will take the THC and measurement of uncertainty into consideration. The rule provides an example of how these calculations will work:

if a laboratory reports a result as 0.35% with a measurement of uncertainty of +/- 0.06, the distribution or range is 0.29% to 0.41%. Because 0.3% is within that distribution or range, the sample, and the lot it represents, is considered hemp…. However, if the measurement of uncertainty for that sample was 0.02%, the distribution or range is 0.33% to 0.37%. Because 0.3% or less is not within that distribution or range, the sample is not considered hemp for the purpose of plan compliance, and the lot it represents will be subject to disposal.

Notably, the interim rule does not change any other federal laws related to hemp or marijuana. The 2018 Farm Bill defines hemp as the plant species 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 THC of not more than 0.3 percent on a dry weight basis. The Controlled Substances Act definition of marijuana includes certain parts of the cannabis plant (and derivatives thereof) that contain more than 0.3 percent delta-9 THC on a dry weight basis. The interim rule definition of “acceptable hemp THC level” is used for purposes of determining obligations of licensed growers under the Farm Bill (and it accounts for the level of uncertainty in laboratory testing).