(CBS) — A bargaining team for the Chicago Teachers Union unanimously rejected a contract offer from Chicago Public Schools union officials announced Monday afternoon.

The 40-member committee of educators voted on what was described as a serious offer Monday. The union says it rejected the offer, citing the district’s fiscal instability reductions in education quality and does not address revenue concerns. A yes vote would have sent the offer to the union’s House of Delegates for approval.

Dr. Monique Redeaux-Smith, a member of the teacher’s bargaining team, says the contract didn’t go far enough.

“We are not convinced that they will make good on their promises set forth in this proposal that are very vague and unclear,” she said.

CTU says it does not trust Chicago Public Schools nor Mayor Rahm Emanuel to keep their promises

“We’ve already given because people have asked us, ‘don’t you have to give up something?'” said CTU president Karen Lewis. “If you look over the past five years, ten years, 15 years, we have been constantly asked to give and we’re looking at about two billion dollars.”

Teacher Jim Cavallero says there would be “undue pressure” on veteran teachers to retire.

CTU says it does not know when a possible teacher strike could happen, but did say a walkout is possible this school year.

In a statement, Chicago Public Schools CEO Forrest Claypool said, “While we are disappointed by today’s result, CPS remains committed to reaching an agreement with our partners at the CTU that is in the best interest of our students, parents, teachers and city. We are committed to returning to the bargaining table and working around the clock to reach an agreement. As we continue to bargain, we must move forward with plans that restore fiscal stability to the District.”

Negotiations on a new deal have dragged on for more than a year, and the previous contract expired in June.

According to the Chicago Sun-Times, the 4-year deal would have phased out the so-called “pension pickup.” Since 1981, the city has agreed to pay for 7 percentage points of the 9 percent pension contribution for every CTU member. CPS would stop paying half of that in July, and the remaining half a year later. CTU members also would have had to start paying part of their health insurance premium.

Teachers would have gotten raises of 2.75 percent next year, and then 3 percent for the following two years. They also would have continued to receive step and lane increases that are based on factors such as their education and experience.

The district also would have capped charter schools at existing levels, and could only open new charter schools after closing existing ones. CPS also promised to halt economic layoffs for the duration of the deal.