Increased Cannabinoids Concentrations Found in Specimens From Fatal Aviation Accidents Between 1997 and 2006

The Civil Aerospace Medical Institute's toxicology laboratory receives biological specimens from more than 90% of all fatal aviation accidents that occur in the United States and its territories. As a part of the routine analysis of pilot specimens, the laboratory tests all cases for the presence of marijuana (cannabis). The National Institute on Drug Abuse (NIDA) and the Office of National Drug Control Policy (ONDCP) reported a 1.5-fold increase in the delta-9-tetrahydrocannabinol (THC) content of street cannabis seizures from 1997-2001 to 2002-2006. This study was conducted to compare the changes, over those years, in blood and urine cannabinoid concentrations with the potency of THC reported in the cannabis plant. In our laboratory, cannabinoids are screened using radioimmunoassay (RIA) for blood and fluorescence polarization immunoassay (FPIA) for urine and confirmed using GC/MS. A total of 95 individuals were found to be using cannabis from a total number of 2769 (3.4%) individuals tested over the period 1997 through 2006. Blood was received for analysis from 1676 fatally injured individuals. Urine was received for analyses from 1650 fatalities. Cannabinoids were found in 88 of the 1676 (5.3%) blood specimens received for analysis, and 64 of the 88 were from pilots. Cannabinoids were found in 68 of the 1650 (4.1%) urine specimens received for analysis, and 57 of the 68 were from pilots. Other impairing drugs were found in 39% of the cannabinoids-positive individuals. The mean concentration of THC in blood for 1997-2001 was 2.7 ng/mL; for 2002-2006, it was 7.2 ng/mL, a 2.7-fold increase in the mean THC concentration of specimens from aviation fatalities, compared to a 1.5-fold increase in cannabis potency reported by the NIDA and ONDCP over the 10 years of this study. The median age for cannabis users was 42 years (range 18-72) for aviation fatalities. Work was accomplished under approved task AM-B-09-TOX-206.