INTRODUCTION: This study investigated exposures involving ∆8-tetrahydrocannabinol (∆8-THC) reported to US poison centers (PCs), including variation among states and regions. It evaluated whether the ∆8-THC exposure rate was lower among states with ∆8-THC regulations and states where cannabis (∆9-THC) use was legal.

METHODS: National Poison Data System data for ∆8-THC exposures in 2021-2022 were analyzed, including comparisons of state and regional population-based exposure rates.

RESULTS: There were 4,925 exposures involving ∆8-THC as the primary substance reported to US PCs from January 1, 2021, to December 31, 2022, with 69.8% of these reported in the US South. The rate of exposure per 100,000 US population increased by 79.2% from 0.53 in 2021 to 0.95 in 2022. In 2022, the mean rate of ∆8-THC exposures in states where cannabis use was illegal was 1.64 per 100,000 population (95% CI: 1.08-2.20) compared with 0.52 (95% CI: 0.29-0.76) in states where cannabis use was legal (P = 0.0010). In 2022, the mean rate of ∆8-THC exposures in states where ∆8-THC was unregulated was 1.36 per 100,000 population (95% CI: 0.95-1.77) compared with 0.17 (95% CI: 0.06-0.27) in states where ∆8-THC was banned (P < 0.0001).

CONCLUSIONS: The rate of ∆8-THC exposures reported to US PCs increased by 79% from 2021 to 2022, with the US South accounting for more than two-thirds of exposures. The rate of ∆8-THC exposures reported to PCs was significantly lower among states where ∆8-THC was banned and among states where cannabis use was legal. Consistent regulation of ∆8-THC across all states should be adopted.