A debate about whether to set marijuana policy based on potency is spreading as more states legalize cannabis.
Under a law signed last month, New York will tax recreational marijuana based on its amount of THC. That's the main intoxicating chemical in cannabis.
Illinois imposed a potency-related tax when recreational pot sales began last year.
Vermont is limiting THC content when its legal market opens as soon as next year.
Supporters say such measures will protect public health.
Opponents argue that THC limits could drive people to buy illegally and amount to beginning a ban on pot again.
