Trivia: This episode bares some resemblance to the story of Captain Marvel, also known as Shazam. In it, young Alec Abrams magically turns into an adult, Steven Swift who is the superhero Angel Warrior. Stephen Swift is played by Carlo Marks. Marks appeared in season 7 as Chloe's fiancé in an alternate reality where Kal-El never came to Earth.
Trivia: When Clark saves Oliver he gets a bullet on his eye just like Brandon Routh in Superman Returns.
Answer: The kryptonite only creates mutations when it reacts with the environment and an individual. Remember, the FDA and several environmental groups did check out Smallville after the meteor shower, but found no danger in the rocks. Obviously they're not always emitting mutating rays, or all the flora and fauna of the surrounding area would be horribly mutated.
Phoenix