Audio problem: Teyla's audio sounds way more high pitched then normal, either dubbed or a post production mistake. (00:06:00)
Continuity mistake: Before Merell enters the cage to be fed on by the Wraith, his collar is open. Next shot when he enters the cage the collar is fully buttoned. (00:28:08)
Revealing mistake: Steve (Wraith)'s belly appears not to match the rest of the Wraith character's skin tone. Clearly, it is a human body rather than an alien. (00:31:36)
Answer: Those are actually suits that protect from hazardous chemicals. They are cheaper for the prop department and look nearly the same as biohazard suits. A real biohazard suit would indeed have a helmet that seals to the neck.
Grumpy Scot