I am not a scientist...and I didn't formulate spinosad, however I did stay at a holliday inn last night
I wouldn't worry about it though...in all seriousness. Spinosad is a live culture, a microorganism. It hasn't shown any harm to mammals...especially humans. My grow room is less than 3 feet from where I sleep at night...I haven't noticed any ill effects yet...yet. lol But that doesn't mean anything really...
I might drop dead in 10 years cause of this...you never know.
Carpet is a no no for any grow room...for lots of reasons. It is a perfect 'safe harbor' for all sorts of nasties...mold, pathogens, bugs, etc. If you can...rip that shit up and put down something a little less giving. I tore out my carpet in the height of my thrip problems...and guess what I found down underneath the carpet padding?
If you can't rip the carpet out...I would spray with the spinosad. Use caution though...I haven't tested this stuff on carpet to see what it does, if anything. My advice on that would be to test a small corner piece of carpet and wait a week. IF you notice anything you don't like...then don't spray.
Spinosad works by direct contact...or by ingestion. Theoretically you could spray the carpet and when the thrips came in contact they would be killed. But how thoroughly would you need to drench the carpet to get 'contact'...I don't know.
It is good practice to tear down and clean walls, floors, and all surfaces thoroughly in between runs. This will only make your job as a caretaker much easier. Remember, preventative maintenance is the best kind of maintenance in an herb garden.