A D.C. Council committee will weigh a proposal Friday to outlaw synthetic marijuana, moving the District closer to joining the 39 states that have already banned the chemicals that experts warn can be as dangerous as traditional pot.

Under the law Council Chairman Kwame Brown and nine other legislators proposed in November, the District would add stimulants containing any of nearly two-dozen specific chemicals to the city’s controlled-substances law. Those chemicals simulate the effects of marijuana when applied to plant products.