As in 2018, 2017, 2016, 2015… The reason is very simple: the lethal dose of smoked cannabis is not attainable.
Can you really overdose on cannabis?
As explained before, some studies have looked at the lethality of cannabis. Although it exists in theory, and in practice intravenously, it would take phenomenal amounts of cannabis to smoke at one time. The most advanced study on the subject compared to different intravenous and ingested dosages in animals.
When ingested, the tests went up to 3000 mg/kg of THC in dogs and monkeys, without reaching a lethal dose. The equivalent for a human would be to eat 2 kilograms of weed at 10% or 200 g of a 100% THC extract, which seems more “attainable” but apparently not lethal either.
Intravenous doses of 92 mg/kg of THC caused no deaths in monkeys, but all monkeys died from 128 mg/kg. This 92 mg/kg dose would be comparable to an instantaneous consumption of 12.8 grams of pure THC, or 128 grams of 20% weed at one shot, assuming 50% THC destruction by combustion.
Cannabis, on the other hand, can be used to combat opiate overdoses.