The shooting took place at the Bunn-O-Matic plant on Friday morning, reports Xinhua news agency local media as saying.
The suspect, Michael Collins (48), then fled the scene and was later found dead in his car of a self-inflicted gunshot wound, with two handguns besides his body.
Police officers found the bodies of the two male victims, one in his 20s and the other in 60s, in warehouse.
A woman in her 50s was found injured in the parking lot and was rushed to the hospital in critical condition, local media quoted Springfield Police Chief Kenny Winslow as saying during a news conference.
The suspect was a coworker of the three victims, Winslow said.
Police believe Collins acted alone in the shooting.
His motive is still under investigation.