In 2268, Carter made the last log entry recorded prior to the death of the Exeter crew following their exposure to a bacteriological agent native to Omega IV that had been brought aboard by the non-immunized landing party.
Dr. Carter was in sickbay during the time of the infection and was attempting to cure crewmembers, among them the chief engineer. Carter went to the bridge and made a final log entry before his and the Exeter crew's death. Carter died in the command chair. His uniform was later found draped on the floor beside the chair, his body reduced to dehydrated crystals by the infection.