An employee shot and killed a supervisor and four others after an argument at a western Kentucky plastics plant, then turned the gun on himself, police and a company official said Wednesday.

The shooting happened around midnight at Atlantis Plastics in Henderson, KY.

The employee, a press operator, began arguing with a supervisor and was escorted from the building, company CEO Bud Philbrook told The Associated Press.

As the employee was leaving, he took out a gun, shot the supervisor, then charged back into a break room and shot several employees. Then he returned to the floor and shot another employee before killing himself, Philbrook said.

"It's just total shock. It's something you read about in the paper what happened at one of our facilities," Philbrook said.

It wasn't clear if the employee was carrying the gun, or if he retrieved it after the argument. Under Kentucky law, business owners are allowed to prohibit people from bringing weapons onto the premises.  "We don't know if the gun was in the car or if he went somewhere to get it," Henderson police Lt. David Piller said.

At least one other person was injured, police said. The wounded victim was taken to St. Mary's Hospital and Medical Center in Evansville, Ind., spokeswoman Cheryl Dauble said. That person was undergoing treatment, she said, but declined to release further information.

The names of the shooter and the victims were not released.  However, Henderson County Coroner Bruce Farmer confirmed that the supervisor was among the dead. He said autopsies for all six were planned Wednesday.

"We're still in the process of contacting families and interviewing witnesses," Farmer said.

The Atlanta-based company has 1,300 employees worldwide, and about 150 in Henderson, where workers make parts for refrigerators and plastic siding for homes.

Henderson County Judge-Executive Sandy Watkins said the tragedy has shaken the entire town, partly because so many residents are either related to or know someone working at the plastics plant.  "Our whole community is in shock," Watkins said.

Other employees at the plant were sent home. Between 35 and 40 were inside at the time of the shooting, Philbrook said.

In a news release on the company's Web site, Atlantis Plastics said it is a leading U.S. manufacturer of three kinds of products: polyethylene stretch films for wrapping pallets of materials, custom films for industrial and packaging uses, and molded plastic pieces used in products such as appliances and recreational vehicles.