BOISE, Idaho -

A Boise call center that helps people sign up for health insurance under the Affordable Care Act is laying off nearly its entire work force as the federal exchange open enrollment period ends.

Maximus Inc. hired about 1,800 people for the Boise facility last year.

In a letter to employees on Monday, company officials announced that 1,600 employees will be laid off in April because they won't be needed when the federal enrollment period ends. Company officials say some employees may be hired back this fall, in preparation for the next enrollment period.

The news came as a surprise to a group of nine employees suing Maximus over alleged violations of overtime laws. Their attorney, Jeremiah Hudson, says his clients believed their positions were permanent, not seasonal.