The teachers union representing the Hacienda La Puente Unified School District has walked away from the negotiating table and is expected to declare an impasse, union officials said Wednesday.

The Hacienda La Puente Teachers Association said it intended to file impasse papers Thursday, said Eileen Fetters, HLPTA executive officer.

Such a filing will require the Public Employee Relations Board to send in a third-party mediator to help bring the two sides to an agreement.

That could delay contract negotiations for weeks or months, Fetters said. The teachers and the district have been in contract talks for 19 months.

The teachers and the district do not see eye to eye over salary and benefits, Fetters said.

At issue is a $1,750 yearly payment from the district to each teacher to offset a higher individual share of health care insurance costs. The payment will expire Jan. 1, 2013, Fetters said.

But HLPUSD Supervisor Barbara Nakaoka said the teachers union is really asking for a $5,000 a year bump in salary.

Read more in Steve Scauzillo’s story IMPASSE.