Avista Corp., of Spokane, said Thursday that 56 employees have been approved for a voluntary severance program and will now be terminated at the end of the month.

In October, Avista offered more than 900 nonunion employees the option to leave the company through the program.

About half of those employees who applied for the program received approval, said Avista spokesman Dan Kolbet. Avista customers won't notice a difference in service, he said.

Avista filed documents with the U.S. Securities and Exchange Commission saying the cost of the severance program will be $7.5 million. That includes severance, employee benefit costs, and payroll taxes.

Kolbet said the cost savings will top the program cost in about a year and a half.

"It becomes sustainable savings going forward," Kolbet said.

He said the company would not disclose the estimated savings from the program.

With 56 people terminated, the company will shuffle people around internally and some employees will be taking on new responsibilities, Kolbet said.

"We really achieved what we set out to do with the program," Kolbet said. "We don't anticipate any further actions at this time. But we'll re-evaluate if the situation changes."

The last day for the 56 employees who took the voluntary severance is Dec. 31.

The severance package includes two weeks of pay for every full year of employment.

The program was offered to nonunion, full-time and regular part-time employees.

Union workers, such as linemen, service crews and dam operators didn't have the option. Avista utility officers kept employees who were too difficult to replace and are vital for reliable service.

Avista will make new hires in 2013 as other employees leave during the year, he said.