The document summarizes data from biomedical sensors on the three astronauts aboard Apollo 1 - Virgil Grissom, Edward White, and Roger Chaffee. In the minutes before a fire was reported, the sensors showed the Senior Pilot's pulse and breathing increasing slightly on two occasions, indicating some muscular activity but not an alarm response. By 23:30:45 GMT, the biomedical readings had returned to normal resting levels.