Dressed in a UPS uniform, the unidentified man opened fire at a United Parcel Service Inc package sorting hub on Wednesday.
According to police, two other people were also shot and taken to hospital as two firearms were recovered from the scene.
Police ruled out speculations that shooting was terrorism-related.
The shooter and the victims, who were all drivers, had gathered for their daily morning meeting ahead of going out on their routes, said Steve Gaut, the head of investor relations at UPS.
“The company is saddened and deeply concerned about affected employees, family members and the community we share. Our thoughts and prayers are with all those touched by this incident,” UPS said in a statement.
There was a heavy police presence in the area in the aftermath of the shooting with workers being led out and embracing each other on the sidewalk outside.