ROCKLAND, Maine — Overspending in the Regional School Unit 13 lunch program is behind the financial crunch that has led to a spending freeze, grounding field trips and nonessential purchases.

Auditor Ronald Smith said that without changes, the deficit in the school lunch program over the past two years and this year could hit $500,000.

The auditor, who spoke before the school board Thursday night, also said he could not certify the accuracy of financial records for the district that are required to be filed with the state. He said the district has been in consultation with the Maine Department of Education for an extension of the Nov. 1 deadline to file records on what the district spent in 2012-2013.

There were many mistakes in financial postings, he said.

The 2013-2014 budget is contingent on using $930,000 in money unused and available from 2012-2013 but Smith said his review of financial records has determined that there will only be $750,000 available. He said after the meeting that this was an optimistic estimate.

“This is pretty devastating,” RSU 13 Board Chairwoman Esther “Tess” Kilgour said.

Superintendent Lew Collins said he was unaware of the lunch program financial woes until recently. Board member Donald Robishaw Jr., chairman of the board’s finance committee, said he also was unaware of a problem.

Board Vice Chairman Loren Andrews of Cushing criticized the tone of Thursday night’s meeting.

“I feel like this is a setup against a certain employee. This is being choreographed with questions written in advance to make an employee look bad,” Andrews said.

Board member Sally Carleton of Owls Head said that this was not a new problem and that the district has overspent on the school lunch program for years.

Smith agreed that the problem was not limited to RSU 13 but said it was an escalating program with the Rockland-area district.

The auditor also said that despite claims being circulated by some people within the district administration that there was overspending in the special education program this year, he found that was not the case.

“Your budget this year is well within its constraints,” he said. “That’s good news.”

After his presentation and outside the meeting, the auditor declined to say who was making claims about special education overspending.

Collins managed the special education program until a few months ago after the previous director left during the last school year. The district hired a new director, Erin Frazier, at the beginning of the summer. Administrators and teachers have filed letters to the board expressing concerns over Collins management.

The board met in a closed-door session last month with its auditor, business manager Scott Vaitones and school district lawyer Campbell Badger to discuss unspecified issues. No one involved would discuss what transpired in that meeting.