General Motors is investing $500 million and recalling 400 laid-off employees in Spring Hill, Tennessee, the Tennesseean reports. The company will build a new assembly line for a next-generation four-cylinder Ecotec engine.

GM already produces two Ecotec four-cylinder engines in Spring Hill, employing 400 people. The engines are used in the automaker's Chevrolet Malibu and Equinox, GMC Terrain, and Buick Lacrosse models.

The engines currently produced in Spring Hill would be exported, while the newer model would be used in GM vehicles for the North American market.

The United Auto Workers union said workers would be called back based on seniority.