Other mistake: Lois digs up Chloe's grave site to unearth her casket. It is obvious that the casket is not buried six feet deep. You would think, with all that is going on, that LuthorCorp would have at least buried the casket deeper to deter inquisitive eyes and maybe throw in a few scattered bones for good measure.
Plot hole: In episode 4-16: "Lucy," there is no reason for the criminals to be chasing Lucy on the ski slopes at the beginning of the episode. We learn later that she's been working with them all along; she calls Lois during the chase, and the call is part of Lucy's plan with the criminals. Lucy being chased by the criminals would make sense given the story she gives Clark during the next part of the episode, but it doesn't make sense for what we ultimately learn is the truth. And nobody from Smallville is anywhere near the ski chase, so it also doesn't make sense as any kind of a ruse.
Continuity mistake: Just before the final play of the game starts there is a shot of the scoreboard. The scoreboard reads 4th and 10 (yards) with 10 seconds to go. The announcer then says it is 4th and 1 with 10 seconds to go.
Plot hole: During the flashback scene showing how Chloe and her father survive the house explosion it is explained that there was a team in the house and they grab Chloe and her father and rush them into a tunnel just seconds before the house explodes. However, as seen in the episode Covenant, Chloe is standing next to the door and Chloe's father is more than 15 feet away from her when the door of the house shuts. As soon as that door shuts the house explodes so unless this S.W.A.T. has Clark's super speed ability this would be very much impossible.
Other mistake: In episode 4-14: "Krypto," Genevieve tells Jason that the heirs of a 17th century woman named Gertrude are in danger. She then tells him that they themselves are "Gertrude's ancestors." But she must mean descendants, which means the opposite of ancestors.
Continuity mistake: After Lois hits the dog, she exits her car and runs to the dog. As she passes the back of the car, her tail lights are off. When she reaches the dog, her tail lights are on.
Continuity mistake: After Clark gives Chloe the piece of paper with the list of cars that checked into the hotel, Chloe holds the paper in front of a folded up newspaper. Between shots, the newspaper turns the direction it faces. Then in the next shot, Chloe is only holding the piece of paper, and the newspaper that she was holding behind it has now disappeared.
Continuity mistake: Lana looks over the edge of the crater and there is a fire right in front of her on the inside rim of the crater. When the shot changes and pans up to an overhead view of the crater and ship that fire is missing.
Continuity mistake: When Jason starts knocking on Lana's door, the clasp from the door chain is all the way to the left. The camera cuts to Lana in bed. When it cuts back to the door, the clasp is now all the way to the right.
Plot hole: When Dawn enters Clark's body, she slaps Chloe in the face with the back of the hand, and Chloe goes flying. A few minutes later, we see Chloe get up and say that she's fine. Getting backhanded by Clark would make you very far from fine. First of all, Clark can knock someone out just by tapping them on the forehead, as seen in a previous episode. Second, Dawn has no idea of Clark's powers, so she would have used way more force than she actually needed to. The amount of force inflicted from the attack should have caused fatal injuries to Chloe. There's not even a cut or bruise or anything.
Continuity mistake: As Trent and Lionel talk, while Lionel is in the hospital bed, when the camera is behind Trent his shoulder and neck are barely illuminated and is in shadow as the camera is looking down on Lionel. When the camera is looking up at Trent, even though he has not moved, his shoulder and neck are now brightly lit and shows no sign of a shadow.
Continuity mistake: As Lana and Lex are talking, as Lana says "Actually, umm, I came by because.". In the middle of her going "umm" there is a camera change. Before the change Lana has her right hand on the arm of the seat. After the change she now has her right hand scratching her head.
Revealing mistake: Kristin Kreuk's body double in the shower scene is noticeable. She is slightly larger and differently shaped.
Visible crew/equipment: As Jonathan is being attacked by Hercules you can see that Jonathan, or his stunt double, has on a arm cuff that is used for protection of attack dogs.
Revealing mistake: When Lucy plays her violin in Lex's mansion, it's obvious the actress isn't actually playing - her fingers aren't moving and the box is out of time with the music.
Audio problem: As the band is playing right before Clark and Lois enter the prom, the drums are not synced with the music.
Continuity mistake: When the offensive line is first shown, as they sit on the bench, the shot is of them from behind. In that shot the team jersey numbers are in this order 89, 46, 8, 66, 1. Then the camera view changes to be in front of the players only now going from the players left to their right is 99, 46, 8, 66, 89.
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