Hey Robyn,
Unfortunately, there's no real way of checking in Tealium itself but if you were to push a tag out (e.g. Google Analytics) and configure it to only go live on 'dev' or 'qa' (
https://www.evernote.com/l/AI7NuBR1W5ZDrKv32LySm9nluQhJqc6yWTw) you could check what domains are being reported on by GA?
You wouldn't be able to see any domains which didn't get traffic though but it might be a good first step (especially if you leave it on for a while).
Hope this helps...
Cheers,
Roshan