A committee of Colorado lawmakers revived a limit on stoned driving Wednesday, just two days after a different committee killed the proposal.

The limit — which would define a THC blood level at which juries could consider people too high to drive — died in a state Senate committee on Monday after lawmakers raised questions about the scientific certainty of the pot impairment measurement. It was the fourth time in three years that legislators in the Senate have rejected a stoned-driving limit.

The limit’s resurrection came Wednesday in a hearing of the House state affairs committee, which heard a major bill on marijuana regulations. The sponsor of that bill, Denver Democratic Rep. Dan Pabon, proposed amending the stoned-driving limit into his bill, House Bill 1317.

“If we’re going to allow marijuana to be legalized, we must have some standard,” Pabon said.

The amendment drew support from several state officials. Deputy Attorney General David Blake told the committee his office wouldn’t support the marijuana regulations in their entirety if a stoned-driving limit wasn’t part of them. Later, Gov. John Hickenlooper posted on Twitter that he supports placing the stoned-driving provision in the regulatory bill.

But some lawmakers on the committee said the limit had already been considered and defeated.

“It’s had its day in the legislature, and it will have its day next year,” said Rep. Joe Salazar, D-Thornton.

The committee ultimately approved the limit on a 7-4 vote that crossed party lines.

Pabon’s bill lays out the regulatory structure for Colorado’s forthcoming recreational marijuana stores. As it is written, the bill allows marijuana growers and sellers to operate separately — the opposite of how “vertically integrated” medical-marijuana dispensaries operate and also contrary to the recommendations of a special state task force on recreational marijuana. Pabon abruptly pushed for the more open model at the last meeting of the legislative committee that wrote the bill, catching some of his colleagues off guard.

An open model benefits would-be marijuana entrepreneurs who don’t already have a stake in medical-marijuana businesses. An unusual alliance of law enforcement officials and medical-marijuana business owners emerged to oppose the open model.

On Wednesday, Pabon said he will offer a compromise that requires growers and sellers to operate under the same company until at least October 2014. After that, people could open stand-alone marijuana shops or wholesale cultivation businesses, Pabon said.

“The regulatory model you have in the bill will not be in the end proposal,” he said.

A deeply divided state affairs committee passed the bill by a narrow 6-5 vote.

Lawmakers have only about two weeks to pass Pabon’s bill and two others on marijuana regulations and taxes before the end of the session.

John Ingold: 303-954-1068, jingold@denverpost.com or twitter.com/john_ingold