The Drug Enforcement Administration's new leader, Chuck Rosenberg, is now certain: Heroin is without a doubt more dangerous than marijuana.

Rosenberg nearly reached this conclusion during a conference call last week when he said marijuana is "probably not" as dangerous as heroin, before adding "I'm not an expert."

The comments were praised as a step forward by some drug policy reformers. Rosenberg's predecessor, Michele Leonhart, famously refused to give an answer. Others, however, ridiculed him.

DEA spokesman Rusty Payne tells U.S. News that Rosenberg voluntarily addressed the matter Wednesday to clear the air.

"Heroin is clearly more dangerous than marijuana," Rosenberg said at a press conference, as first reported by Matt Ferner of The Huffington Post.

Other topics at the event included the escape of drug lord Joaquin "El Chapo" Guzman from a Mexican prison, cartel violence, synthetic drugs and internal management issues, says Payne, who couldn't recall particular points Rosenberg made in contrasting heroin and marijuana.

"The obsession with marijuana that you guys have is sometimes – come on!" Payne says. "Of all the things in the world, that's what you're worried about? Come on, dude. Really?"

Four states have laws allowing regulated markets for recreational marijuana. Many others regulate sales of medical marijuana. Almost all marijuana possession, however, remains a federal crime, with DEA agents and federal prosecutors at times targeting people who roughly comply with state laws.

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The DEA also has a role in the administrative scheduling of drugs. Advocates say a change in marijuana's listing as a Schedule I drug could expand research possibilities and open the door to its future use as an unequivocally legal, insurance-covered prescription.