Concord Police Deputy Chief Guy Smith said officers were using a helicopter and police dogs to hunt for the shooter, who was seen running away from the Sun-drop Bottling Co. carrying a box.
"We have 25 to 30 investigators who are following every lead," Smith said. "When someone is carrying a box from the scene, you want to talk to them."
Smith said the shooter walked into the plant's office around 10 a.m. during what they believe was a robbery. An employee called police a short time later and told dispatchers there were two people down at the plant, he said.
One of the victims worked at the company, Smith said. Police have released no other information about the victims, and said they don't know the shooter's identity or if there was a relationship between the shooter and the victims.
Sun-drop Bottling manufactures soft drinks and spring water at the plant about 25 miles north of Charlotte.