Those agreements between Big Tobacco and states restricted ads, promotions and sponsorships aimed at children and teenagers. Colorado, like Massachusetts, does not allow additives in marijuana for medical purposes. Both states require testing so that consumers will know how strong different ingredients are in the marijuana they buy.

But Levy worries about the loopholes. She points out that the tobacco industry is often accused of skirting youth restrictions with candy flavored cigarettes, for example, that appeal to youth even if they are not direct marketing.

“I’m beginning to have a sense of déjà vu about this,” said Richard Daynard, a law professor at Northeastern University who has focused for more than 30 years on tobacco liability cases. He says marijuana is different.

“It’s never going to be as deadly as tobacco, but that’s not saying very much,” Daynard continued. “That’s the world we’re about to enter, so I think the best advice would be, stop, look and listen before we go there.”