There was something bugging me when I got back from the recent conference I attended... but it wasn't until I refilled the re-usable water bottle from my office that I remembered what it was. Those two gentlemen sitting near me during a break were talking loud enough for me to hear and become interested: "Hey Charlie, I'm ok - my bike bottle is a 2 and my other bottle is a 1 - so thanks for the info". Once it was clear that they were discussing the safety of plastic drinking bottles, I had to ask them to inform me. They told me that the codes on the bottom of every plastic bottle indicate different plastics which correlate to the safety of the bottle.. "1's are the safest and 7's are the most dangerous, generally", they said. "Wow - thanks guys - I'll take a look when I get home!".
So a few days later, with my new "green" water bottle in hand, I remember this discussion and flipped over my bottle - huh? "SEVEN!?", I said out loud. Time for some research, since it's hard to believe I would be given a water bottle which is good for the environment but bad for me. Well - it turns out I wish I had gotten the contact info for those two gentlemen - no, not to yell at them - but to tell them the facts. The codes are there as information for recycling - to identify the resins which make up the bottle. They're not intended to indicate safety.
The codes do provide, in a few cases, enough information to know you should avoid a certain bottle - for example, Code 3 is PVC (PolyVinyl Chloride) and Code 6 is PS (Polystyrene) - those seem to be universally accepted as the "avoid at all costs for food and drinking" type. Code 7, it turns out, is the "Other" type, which is a catch all to mean "either really dangerous (Polycarbonate) or really safe or something in between, depending on what it's made of". Ah, really helpful. And while Code 1 (PET/PETE - Polyethylene Terephthalate) is the most common for recyclable drink bottles in the US, just don't re-use it, heat it or scratch it. It seems the other codes - 2, 4 and 5 - just haven't had any conclusive research as of yet. Does that make them safer than those we know can harm you?
Regarding the relative "safety" of one type of platic versus another - particularly when using the recycling codes as virtually your only consistent guide - the LfT-Group (Live for Tomorrow) sum it up best:
"You may wish to seriously consider your – and especially your children's – use of plastics numbered 1, 3, 6 and 7 (polycarbonate), all of which have been shown to leach dangerous chemicals. This does not necessarily mean the others are completely safe, just that they have been studied less to date. So if you have to use plastic, it is safest to stick to numbers 2, 4, 5 and 7 (other than polycarbonate) whenever possible."
In my quick search for information (not the same as "research"), I found a few more links worth sharing with those of you who cared enough to read to here:
Health facts by each recycle rating
Lots of health information by each recycle rating
Complete information by each recycle rating (pdf)
Plastic bottle quick FAQ by type
Plastic bottle safety FAQ
General information on plastic rating system (wikipedia)
Good article on plastic containers
Be plastic-aware - dangers of each type
International Universal Recycling Codes
Official Recycle coding system from Hong Kong Environmental Protection Dept.
(NOTE: The folowing are internet sites of the American Chemistry Council® (ACC), which represents the leading companies engaged in the business of chemistry, including significant business groups such as the Plastics Division and the Chlorine Chemistry Division.)
American Chemistry Council's (ACC) Facts on Plastics site.
ACC Rumors and Myths about Plastics
ACC 2006 United States National Post-Consumer Plastics Bottle Recycling Report
ACC Official Resin Codes Chart (PDF)