Legal Update: Cannabinoid Testing and the Iowa Intoxication Defense

On 6/2/2026, the Iowa District Court for Polk County issued a ruling in Happel v. LA Leasing that will have a significant impact upon how defendant-employers may use the intoxication defense moving forward.

In the Happel case, Claimant fell off a ladder at work and was brought to the ER. At the ER, she took a drug test and tested positive for “cannabinoids.” Based on the results of this exam, the employer denied her benefits. At hearing, they used the intoxication defense to justify this decision, arguing that marijuana contains a hallucinogen in the form of THC. However, the drug test conducted at the ER did not test specifically for THC. It only searched for the general category of “cannabinoids,” and not all cannabinoids contain THC. No further testing was performed on Claimant’s urine sample to confirm whether she specifically had any THC in her system.

Under these facts, the Agency found for the defendant, finding that the test results and Claimant’s admission that she smoked marijuana 2 weeks before the injury were sufficient to presume intoxication. However, the District Court disagreed with the Agency’s assessment.

The court began its analysis by examining Iowa Code section 85.16(2)(b), which states:

1) If the employer shows that, at the time of the injury or immediately following the injury, the employee had positive test results reflecting the presence of alcohol, or another narcotic, depressant, stimulant, hallucinogenic, or hypnotic drug which drug either was not prescribed by an authorized medical practitioner or was not used in accordance with the prescribed use of the drug, it shall be presumed that the employee was intoxicated at the time of the injury and that intoxication was a substantial factor in causing the injury.

(2) Once the employer has made a showing as provided in subparagraph (1), the burden of proof shall be on the employee to overcome the presumption by establishing that the employee was not intoxicated at the time of the injury, or that intoxication was not a substantial factor in causing the injury.

Iowa Code § 85.16(2)(b).

The defendant-employer in Happel argued that the drug test claimant took at the ER tested positive for a hallucinogen, by virtue of the fact that Claimant tested positive for “cannabinoids.” However, as Claimant pointed out, the drug test did not test specifically for THC – the substance in marijuana that is actually hallucinogenic. As such, she argued that the test did not prove that she was under the influence of a hallucinogen at the time of the accident and did not satisfy the requirements of Iowa Code section 85.16(2)(b)(1).

In its decision, the Court ultimately agreed with the Claimant, finding that Claimant successfully rebutted the presumption that she was intoxicated by pointing out that the ER test did not test specifically for THC. The case has been remanded to the Agency to determine if the defendant-employer can provide evidence under 85.16(2)a that the Claimant was intoxicated at the time of the injury.

Happel v. LA Leasing contains useful lessons for any defendant-employer hoping to use the intoxication defense to argue that they are not liable for the injuries of an employee who tested positive for marijuana at the time of their injury. Most ERs use immunoassays to determine what drugs are present in a patient’s system. The majority of immunoassays, however, do not distinguish between THC specifically and other cannabinoids. Instead, they test broadly for ‘cannabinoids’ or ‘marijuana metabolites” – and, as seen in Happel v. LA Leasing, such a finding is not adequate to successfully mount an intoxication defense. To determine the presence of THC, defendant-employers will need to conduct a more detailed test, such as the Gas Chromatography-Mass Spectrometry.