I thought the safe numbers were 1, 2 and 5?
7 --- that's what they put Gerber baby food into, and on one of the other discussion boards a while back, there was talk about how #7 is very questionable, because when you get to 7 there is a conglomerate of junk in there and no one can fully assess what damage it will do, now or in the long run. Maybe I misunderstood them, though.
*Edit: I found this link that tells which is which: http://www.seventhgeneration.com/learn/news/leachin-teach-guide-safe-plastics-kitchen