The second shift at General Motors Bowling Green Assembly in Kentucky ended late Friday and some 400 workers filed out into the night.
But 20 or 30 remained inside the plant when, in the early morning hours Saturday, alarms inside the factory sounded.
The workers knew what it meant: head to a designated shelter in the basement, said Jason Watson, shop chairman for UAW Local 2164, which represents the hourly workers at Bowling Green Assembly located about an hour north of Nashville, Tennessee.