Does anybody know the name of this episode?

There is one episode that I have seen and love but can't remember the name of it and can't remember it exactly.
Sara and Nick go into a house and it has dangerous chemicals in it or something and so they have to be disinfected in a tent and later nick says to sara I wasn;t looking earlier. Sorry I can't quite remember it but please help! I just need the episode name. Thanx

 

That Was Greg And Sara And It Was 5:19_4x4
they have to do 4 case at once!