Micron Technology has fired four general contractors building the $2.5 billion computer-chip manufacturing plant at Lehi. They will be replaced by Micron subsidiary Micron Construction.

Boise-based Micron still will need Utah subcontractors to finish the fabrication facility, central utility plant and administrative structures.

The contractors’ 4,600-member work force fell to 2,900 Tuesday and is expected to drop to 1,500 by March 1.

Micron spokesman Kipp Bedard said Tuesday that the company still plans to produce chips at the site within three to five years and still plans to employ 3,000 to 4,000 workers.