The Amazing Colossal Man 1957(aka..The Colossal Man

The Amazing Colossal Man (also known as The Colossal Man) is a 1957 American black-and-white science fiction film from American International Pictures. Produced and directed by Bert I. Gordon, it stars Glenn Langan, Cathy Downs, William Hudson, and Larry Thor. It is an uncredited adaptation of Homer Eon Flint's 1928 short science fiction novel The Nth Man. AIP theatrically released it as a double feature with Cat Girl.
The film's storyline concerns a U.S. Army Lt. Colonel who survives a plutonium explosion and grows 8 to 10 feet a day, ultimately reaching 60 feet tall, but loses his mind in the process.
During the 1960s, American International Television syndicated the film to television.
At a military site in Desert Rock, Nevada, a test explosion of the first atomic plutonium bomb does not detonate as expected. When an unidentified civilian aircraft crash lands near the site, Lt. Colonel Glenn Manning runs into the detonation area to rescue the pilot. Once in the detonation area, the bomb goes off, and Glenn gets caught in the radioactive blast.
Surviving the blast but suffering from third-degree burns over almost his whole body, Glenn is treated by specialist Dr. Paul Linstrom and military scientist Dr. Eric Coulter. Glenn's fiancée, Carol Forrest, anxiously awaits a prognosis, but Linstrom refrains from telling her that Glenn is extremely unlikely to survive. The following day, Linstrom and Coulter are stunned to discover that Glenn's burns have completely healed. That evening, Carol is not allowed to see him and learns the military moved Glenn to an army rehabilitation and research center in Summit, Nevada. She drives there and gets admitted entry. Upon entering his room, Carol faints in horror as Glenn has mutated into a giant about 16 feet tall.
The next day, Linstrom tells Carol that Glenn's exposure to the plutonium blast caused his body's cells to multiply at an accelerated rate, resulting in his abnormal growth. Linstrom admits that he and Coulter do not know if they can stop it and that if they do not, Glenn will keep growing until he dies. Awakening the day after, Glenn is initially frightened, then greatly disturbed. Carol sees him the following day to comfort him, but Glenn is now roughly 22 feet tall, distant, and depressed. While the public knows he survived the explosion, the military has kept the truth of his condition secret.
As Glenn reaches 30 feet tall, Linstrom recommends that Carol spend time with him. Despite her encouragement, Glenn is angry and bitter. Linstrom reveals that Glenn's heart is growing at only half the rate of his body, and soon it will not be able to support his enormous size and weight. He warns Carol that Glenn's sanity will decline before his heart finally explodes. That night, Carol tries to console Glenn, but he loses his temper and shouts at Carol to leave him alone.
The following morning, Glenn disappears as Coulter reports to Linstrom that he may have found a solution to Glenn's growth. Led by etc.