WASHINGTON:  If you think the recent liberalization of marijuana laws around the country is only about smoking leaves and buds, think again. For users younger than 25, “hash oil” is where it’s really at. This concentrated resin of marijuana is creating new public safety headaches — even in places where it’s legal.

There have always been forms of the substance, but the resins available today are much stronger than in years past. That’s due in part to the expertise developed by medical marijuana producers, who have learned how to make more potent versions of the oil.

Near Seattle, medical marijuana entrepreneur Jeremy Kelsey shows off a sample of a resin that he markets as extreme pain medication for cancer patients. It looks like dark green Karo syrup. Kelsey calls it “pure THC.”

“There’s pounds literally that went into this dish,” Kelsey says, dabbing at the sticky substance that coats the bottom of a square Pyrex pan.

His product is especially potent because he makes it only from marijuana buds, not, as others do, from leafy matter and stalks. He calls the resin medication, but recreational users have other names for it: “butane honey oil,” “wax,” “shatter” or simply “dabs” — because a little dab will do you.