Audio problem: After Clark asks Lana to have dinner with him, and she says it's not such a good idea, the camera shot changes so that Lana is on the right side of the shot. In that shot Lana's mouth is moving like she is talking to Clark only you don't hear what she is saying.
Revealing mistake: When Clark split's the fence at Belle Reve, just before he pulls it apart you can see the breakaway part of the fence. It is a silver color compared to the gray of the actual fence and runs vertically in front of Clark and between where he puts his hands.
Continuity mistake: While Alicia is in Clark's bed she says "I know you wanted to kiss me, Clark." and while she says this her hand is on Clark's face. The very next shot shows her hand is nowhere near his face.
Phoenix (2) - S3-E2
Continuity mistake: As Morgan Edge hands Lionel the bag with the mason jar of blood the camera is on Lionel's side and bag has a very neatly folded flap to keep the top closed. As Lionel takes the bag, while the camera is on Edge's side, the opening is wrinkled and not folded shut as it was before.
Continuity mistake: At the start of the final race there is a bridge at the far end of the road that Pete and Jason are going to race to. During the entire race they never pass this bridge yet it ends up behind Jason's car when Pete looks in his rearview mirror as the crash is going on.
Visible crew/equipment: As Clark is ambushed inside Belle Reve, in shots focusing on Lex as he is being beaten by the twin and again a few seconds later, there is a dark object in the upper right corner of the shot. There is nothing in this scene to explain it and it moves with the camera so it is probably some piece of filming equipment. Regardless of what it is, it should not be in the shot.
Continuity mistake: Just before Lex has his father arrested they are talking while Lionel sits behind his desk. In the shot of Lionel from his side of the desk there is a flat panel monitor behind his keyboard. In shots from Lex's side of the desk the monitor is gone. It returns as FBI agent Loder walks in and Lex stands up.
Phoenix (2) - S3-E2
Continuity mistake: When Clark and Jonathan return home, Jonathan collapses on the couch. It shows Clark rushing to his side. But in the next shot where it shows Martha's reaction, you can see Clark rushing to his side again.
Visible crew/equipment: As Chloe is running from the truck there is a shot where you can see the camera shadow on her back as she is completely turned away from the truck.
Revealing mistake: Lana and Clark are supposed to be skinny dipping at Crater Lake. When Clark pops up out of the water and goes "boo" to Lana she spins around and splashes Clark for making her worry. As she starts to splash Clark her body comes out of the water far enough to see she is wearing a tan tube top instead of actually skinny dipping.
Continuity mistake: The bomb that Garret wears has four kryptonite section, one at each of the corners, and each section has three distinct pieces. The pieces glow only from the center core and the outer edge is only green colored and is not glowing. When the shot switches to the CG shot of Garret falling, The camera passes over and grabs the bomb and now the krptonite has a uniform glow and there are now the one block on each corner does not have the three individual pieces.
Continuity mistake: When Seth drops the spoon he was trying to control it drops into the portion of his tray that holds his jello cup. As Clark and Lana walk in the spoon is now in the part that holds the bread crusts.
Visible crew/equipment: As the FBI search the Kent's house, you can see the shadow of the camera as it moves from the kitchen to the hallway next to the stairs. The shadow appears on the right side of the arch between the kitchen and hallway. (00:17:50)
Audio problem: Just before Adam says "If I read something in out friendship that wasn't there." the camera shot is focused on Lana but you can see Adam's mouth in the top left of the frame. In that shot you can see Adam's mouth is saying the line before we hear it.
Continuity mistake: When Chloe and Lionel finish their discussion in the cave the shot focuses on the Naman/Segeth glyph and focuses through the glyph to a transition shot of an island that Lex is on. When we first see this island it is flat and covered with trees. The next time the island is shown there is now a large volcano/mountain that was not their when we first see the island.
Revealing mistake: When Nicholas throws the lighter it is supposed to be lit so that it will light the gas and kill Lana but as it flips through the air, before Clark grabs it, the lighter has no flame at all.
Visible crew/equipment: Safety bars are seen in the stunt car as it flips around and lands on the side of the road. The mechanism that is used to propel the car upward can also be seen.
Plot hole: During Clark's rescuing Lana from the fire in the basement, Clark wakes Lana just before he is grabbed by the coach. Clark then tosses the coach all the way across the room and into a wall. Lana makes no mention of how Clark could toss a full grown man across a room like that even though it happens right in front of her face.
Continuity mistake: As the two racers speed past Clark and Martha, in the truck at the intersection, Pete's red car does not have its neon lights on in the back window and under the rear spoiler. Then in the next shot, while still racing, both the blue neon lights in the back window and the green neon under the rear spoiler are on.
Deliberate mistake: When Clark is chasing Emily at light speed, Clark decides to use heat vision to knock the water tower down. The water tower shouldn't have had enough time to fall down and intercept Emily, seeing as she's travelling too fast.
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