By Lenzy Krehbiel-Burton

TULSA, Okla. (Reuters) – Oklahoma’s Senate could begin deliberations as early as Tuesday on the Republican-dominated legislature’s first major tax increase in a quarter century to secure funds for raising the pay of teachers, who are threatening to walk off the job next week.

The measure, which would raise about $450 million to fund increased pay for teachers, school staff and state workers, passed the House late Monday by a 79-19 vote. But the money may not be enough to satisfy the demands of Oklahoma’s teachers, who rank among the worst paid in the United States.

Low teacher pay became a national focus after educators in West Virginia, whose pay is slightly higher than in Oklahoma, ended a nine-day strike this month that closed schools statewide, after officials approved a 5 percent pay raise for all state workers.

“April 2 is still on,” the Oklahoma Education Association, the state’s largest union for teachers, said referring to the date when it is threatening to shut schools statewide unless funding for a raise was in place.

The Oklahoma union, which has about 40,000 members, has said it is seeking a $10,000 pay increase over three years for teachers and a $5,000 raise for support personnel.

“Our ask is still our ask,” it said in a statement released after the House vote.

Speaking on House floor on Monday, Appropriations and Budget Chairman Kevin Wallace, a Republican, said the measure that passed the House could support a $5,000 pay raise for a beginning teacher and a nearly $8,000 raise for a teacher with 25 years of experience.

The bill calls for raising the production oilfield tax rate to 5 percent on new and existing oil and gas wells and increasing taxes on other items including gasoline, diesel fuel and cigarettes.

According to National Education Association estimates for 2016, Oklahoma ranked 48th, followed by Mississippi at 49 and South Dakota at 50, in terms of average U.S. classroom teacher salary.

Oklahoma secondary school teachers had an annual mean wage of $42,460 as of May 2016, according to the U.S. Bureau of Labor Statistics.

In every state neighboring Oklahoma, teachers earned more, and in neighboring Texas, the mean wage was about 30 percent higher, according to Bureau of Labor figures.

For the past few years, Oklahoma has battled budget deficits stemming from the 2014 collapse in oil prices that hit its large energy industry and slammed state revenue.

(Reporting by Jon Herskovitz in Austin, Texas and Lenzy Krehbiel-Burton in Tulsa, Oklahoma; Editing by Steve Orlofsky)