A legislative panel today gutted — at least for the moment — a bill on stoned driving.

The bill would have set a limit in the blood of THC — marijuana’s psychoactive chemical — above which someone is too high to drive. But by a 6-3 vote, the Senate Judiciary Committee amended the bill to give the limit further study, answering the pleas of cannabis advocates who said the level in the bill would have snared sober drivers, too.

“They agreed with us that the science does not support the bill,” Rico Colibri, with the Association of Cannabis Trades for Colorado, said of the lawmakers’ decision. “But we certainly support safe driving.”

With several votes still to go before reaching the governor’s desk, the bill could be amended back to its original form.

Rep. Steve King, a Grand Junction Republican who is one of the bill’s sponsors, said the bill had been studied enough. He said stoned drivers are an immediate public safety threat and criticized the medical-marijuana industry for not speaking out more forcefully against driving high.

“I think it’s a study at the risk of lives,” King said after the vote.

At the start of the hearing, the bill deemed anyone with a blood-THC level of above 5 nanograms per milliliter too high to drive. Law enforcement officials and some researchers said Monday that limit is well-supported.

“The numbers backed up by the science are reasonable to have in place so that juries can understand what impairment really is,” said Chris Halsor of the Colorado District Attorneys Council.

But medical-marijuana advocates disputed that, pointing to studies suggesting marijuana impairment can’t be pegged to a specific number. Colibri’s group sent lawmakers a 25-page paper of research citations challenging the 5-nanogram limit. And their efforts received an extra boost Monday when William Breathes — the pen name of alternative newspaper Westword’s medical-marijuana reviewer — reported a blood test showed nearly 14 nanograms per milliliter in his blood when he was sober.

The lack of apparent consensus unsettled Senate Judiciary Committee members.

“I don’t feel that I have enough consistent scientific information to know that I’m picking the right number,” said Sen. Morgan Carroll, D-Aurora.

The first chance for King to put teeth back in the bill could come as early as this week, in the Senate Appropriations Committee.

John Ingold: 303-954-1068 or jingold@denverpost.com.