EE notified supervisor that he wanted to see him. When his supervisor arrived, EE then mentioned having chest pains. 911 was called. MHSA was notified. When EMS arrived, they said that the EE wasn't having a heart attack at that time but he needed to go to hospital. EE told EMS that the pain started approx. 15 min. after lunch. EE was taken to hospital where he stayed overnight.