Factual error: Using a Draeger tube to test for nitric acid fume, the instrument made a clicking sound. This device does not click. The bellows pump is squeezed drawing air through the tube. A reaction takes place between the air contaminant and the material in the tube causing a color change. The length of stain is proportional to the concentration.

Revealing: Horatio writes the symbols for sulfuric acid, H2SO4, on a clear board. Both numbers should be subscripts but he writes the 4 as a large number, suggesting a lack of basic chemistry knowledge

Factual error: Nitric acid is a liquid and not a gas. The gaseous precurser is NO2 which combines with water forming nitric acid, HNO3. Neither causes instant death.

Deliberate "mistake": In the episode "Bunk," a man goes in the house looking for his cat. When the cat releases the fumes, it jumps down, but when the man dies, the cat is nowhere to be found. The cat is not mentioned ever again in the episode either.