A bill criticized as a way to let religion into public school science classrooms suffered a major blow Tuesday.

The measure, House Bill 580, failed on a procedural vote in the state Senate that backers needed to pave the way for final legislative debate.

The vote was 19-10, seven shy of the two-thirds majority needed to debate the measure.

The 2011 regular legislative session has to end by 6 p.m. on Thursday, which means that a bill that had been breezing through the legislative process suddenly faces major hurdles.

The tougher rules for getting a Senate debate took effect at 6 p.m. Monday while senators were discussing the textbook measure.

Backers declined to call the legislation dead.

“We may have another shot,” said state Sen. Mike Walsworth, R-West Monroe and Senate sponsor of the legislation.

Opponents were elated by the developments.

“I am really happy that the Senate has finally awakened,” Ian Binns, an assistant professor at LSU who teaches science education, said in an interview.

HB580 would give local school districts new authority to pick classroom textbooks.

Under current law, the state Board of Elementary and Secondary Education plays a major role in directing which textbooks are used in public schools.

The bill would change BESE’s role to one of recommending the books.

In addition, HB580 would lift the current restrictions on local school districts using state education dollars to buy textbooks not recommended by state educators.

Backers said it makes sense to give local educators a bigger voice in textbook selection, and they noted that BESE backed the bill.

However, opponents said the proposal would open the way for those who believe that life began about 6,000 years ago in a process described in the Book of Genesis — creationism.

State Sen. Karen Peterson, D-New Orleans and an opponent of the bill, said during the brief Senate discussion of the measure that it would “allow the possible entry of creationism” into classrooms.

“It actually allows for religion to counter for science in the classroom,” Peterson said.

In an interview, state Rep. Frank Hoffmann, R-West Monroe and chief sponsor of the bill, said the plan is not designed to allow religion in science classes.

Hoffmann called the Senate action “part of the process.

“There were nine people absent,” he said. “I think it is possible it could get the two-thirds vote.”

Peterson said after the Senate vote that she had “tried to educate some members on the floor” about the issue.

The bill won House approval 87-5 on June 8 and cleared the Senate Education Committee last week without objection.

However, it now has to muster two-thirds of each chamber — 26 out of 39 in the Senate and 70 out of 105 in the House — to be debated.

That two-thirds vote requirement applies to bills that have not been voted on in both chambers by the established deadline.

HB580 was being debated by the Senate at 6 p.m. on Monday when the two-thirds requirement took effect. Before that it only required a majority of the Senate, which is 20 votes, to win final approval.

Binns, who testified against the bill, said he understands arguments that the bill would give local school officials more authority to choose textbooks.

“The reason I want this stopped is because there will be one or two school systems that include inappropriate material,” he said.

Voting FOR allowing debate on the bill even though it passed the procedural deadline (19): Sens. Adley, Alario, Appel, Crowe, Donahue, Erdey, Guillory, Kostelka, Long, Morrish, Mount, Nevers, Perry, Quinn, Riser, Shaw, Smith, Thompson and Walsworth.

Voting AGAINST bringing HB580 up for debate (10): President Chaisson and Sens. Claitor, Dorsey, Gautreaux, Heitmeier, Jackson, McPherson, Murray, Peterson and Willard-Lewis.

NOT Voting (10): Sens. Amedee, Broome, Chabert, Cheek, LaFleur, Marionneaux, Martiny, Michot, Mills and Morrell.