Fan Casting The Flash

Jason Peter Garrick is a college student, who, prior to 1940 (later retconned to 1938), accidentally inhales hard water vapors after taking a smoke break in his laboratory where he had been working (later stories would change this to heavy water vapors). As a result, he finds that he can run at superhuman speed and has similarly fast reflexes. Retcons imply that the inhalation simply activated a latent metagene.