This is the first appearance of the character "Natalia Boa Vista". She will remain with the series through the 10th season.
The first appearance of the brighter, and more colourful, CSI lab interior set, implying more natural daylight. Actually a re-design due to the change of soundstage locations, but could be explained within the story-universe as an essential re-design of the lab layout following the traumatic event of the previous season's finale episode.
Adam Rodriguez (Eric Delko) and Brendan Fehr (Dan Cooper) also both work together in the Television series Roswell (1999).