I get a lot of questions about plastic – and until recently I struggled to find a great resource, but I love Renee Loux’s Easy Green Living (pg 120) for its plastic safety information (as well as just about everything else!).
So check it out and learn that 1,2,4,5,7* (asterisk is important here) seem to be safer.
That said, reusing non-plastic bags, mugs, and steel containers present great options for skipping the whole debate (check out company listings on the AKA recommended accessories on www.ashleykoffapproved.com)!