Volvo announced Friday that its North American powertrain plant in Hagerstown, MD, expects to lay off about 600 people in the first half of 2007.

According to a press release, the company expects sales of heavy-duty trucks to drop off significantly because of the high cost of the new, less-polluting 2007 trucks.

Mack Trucks, another member of the global Volvo Group recently announced it will lay off 450 workers at a Pennsylvania plant for the same reason.