The 6-2, 300-pound employee arrived at work Tuesday morning and left briefly, returning with four handguns, including a 10 mm revolver, police told AP. He argued and shot the plant receptionist, then hunted down the 61-year-old payroll clerk, shooting her in the back as she ran from the building.
Witnesses said the man then closed himself in a room and shot himself.
The man's parents told AP that their son got upset with the clerk in July when she told him he had been denied a two-week vacation because he made a mistake in filling out his request for time off.
The parents said he always needed help filling out forms at the plant because of a learning disability. He took the time off, and did not know he was denied the vacation until a boss threatened to fire him if he did not come back to work.
"He was so mad," his mother told AP. "He didn't know he wasn't getting a vacation."