Post-mortem toxicological screening revealed the presence of cannabinoids in the pilot's system. Femoral blood contained 50.1 nanograms per milliliter (ng/ml) of delta9- tetrahydrocannabinol (delta9-THC), and 21.6 ng/ml of carboxy-THC. Pleural fluid contained 11.9 ng/ml of delta9- THC, as well as 41.8 ng/ml of carboxy-THC. Urine contained 272 ng/ml of carboxy-THC.

Delta9-THC is the principal psychoactive cannabinoid found in marijuana, hashish, hash oil and certain hemp products. Delta9-THC is metabolized in the liver, with the formation of psychoactive and inactive compounds. THC compounds are stored in fatty tissue, reaching peak concentrations in four to five days. Metabolic products are eventually excreted and total elimination of a single dose may take up to 30 days.

A number of factors complicate accurate determination of the recency of cannabinoid use including the mode of intake (smoking versus eating), concentration of cannabinoids, and individual variations. Delta9-THC blood plasma concentrations in live subjects of over 2 to 3 ng/ml have been shown to indicate marijuana smoking within 6 hr. Dispersal and redistribution of cannabinoids occurring in the post-mortem interval before sampling for toxicological analysis can alter the presence of cannabinoids in tissues and fluids. This increases the difficulty in the application of formulas to establish accurate usage time frames.