After writing about what the plastic recycling numbers listed on the bottom of plastic containers mean, I have been swamped with questions about which ones are considered safe plastic numbers and which ones are not, especially in the area of food and drink.
Please bear in mind that a lot of research is still ongoing, and new information is coming to light all the time. One example is BPA (Bisphenol A), where a barrage of recent studies have shown the harmful effects of that plastic on the endocrine, neurological, and sexual reproductive systems, as well as on fetal and infant brain development and behavior. It’s therefore impossible to say with absolute certainty whether any particular industrial material, including plastic, is absolutely safe under all circumstances.
Here’s what we do know: some plastics are definitely dangerous or risky, sometimes when heated and sometimes when used under any circumstances. Others are safe if used properly, based on current knowledge and research (or at least based on what I know.)
Here are a few questions I’ve gotten recently, with some answers that hopefully help to demystify the issue of safe plastic numbers:
1) What are considered to be safe plastic recycling numbers?
The absolute safest plastic numbers, especially for storing food, are:
- #2, HDPE, a usually opaque plastic used for milk jugs, detergent bottles, juice bottles, toiletries and the like.
- #4, LDPE, used for things like plastic bags, food storage, bread bags, some food wraps, squeezable bottles.
- #5, polypropylene, used for a wide variety of applications such as yogurt cups, medicine bottles, ketchup and syrup bottles, and straws.
2) What about #1 (PET) plastic?
Current knowledge is that this plastic is generally safe, and is used for things like plastic water bottles. However, in another example of how research is still emerging, an article published in the November 2009 issue of Environmental Health Perspectives provided evidence that PET #1 plastic may leach endocrine disruptors, depending on how it’s used and at what temperature. More research is definitely needed here!
The other concern about #1 plastic is that things like water bottles are intended for one-time use, whereas many people refill them and use them continuously. That increases the chance of the plastic harboring bacteria you might ingest, since it’s difficult to wash and doesn’t resist high temperatures.
3) What plastic numbers contain BPA?
The primary culprit for BPA is plastic recycling number 7. BUT NOT ALL PLASTIC #7 IS BPA! Plastic #7 is a “catch all” category that includes many kinds of plastic that don’t fit the classifications of the other numbers. For example, bioplastics made from sugarcane and corn also carry #7, and these are kinds of plastics we definitely want to encourage people to use.
So the key here is to do your research, and not panic if you see #7 plastic. Many manufacturers of items like athletic water bottles that were previously making them out of BPA are quickly transitioning to other materials in light of the emerging evidence of health concerns.
4) Is it safe to heat up foods touching plastic in the microwave oven?
Personally, I would never do this for ANY plastic, no matter what the number and no matter what the manufacturer says about safety. One problem here is plastic #3, or PVC, which is used in some plastic cling wrapping for food. There are phthalates in PVC, material-softening chemicals that leach from PVC and could interfere with the endocrine system. So I would minimize touching food with this kind of plastic, and definitely not microwave food with it.
As for the other plastics, the risk is yours to take. For my part, I only use glassware or non-plastic plates for heating food, with a paper towel or wax paper to cover it.
5) Is it safe for kids to chew on straws and sippy cups made out of #5 plastic?
I listed #5 as one of the safe plastic numbers, but when it comes to kids do you really want to chance it? The bottom line is that we BELIEVE this plastic is totally safe and therefore theoretically should be OK to chew on. But new information is always coming to light about plastics, and it’s impossible to know with absolute certainty. If it were my children, I would discourage them from chewing on these objects by removing them as soon as the kids are done using them, as well as frequently replace them.
6) Are styrofoam cups safe?
Styrofoam or polystyrene is plastic #6. The general consensus of the medical literature appears to support the view that this type of plastic is safe. There are some nagging concerns, however, such as the Japanese study by Sakamoto Hiromi, about whether and how much polystyrene can leach into food and hot drinks. Given the doubts, my personal view is not to use it for things like hot coffee, using safer mugs instead.
7) Should I use a food container/sippy cup/whatever that doesn’t have a plastic recycling number on it?
I don’t know why some plastics don’t come with a recycling number. In one case I was able to find it by looking it up online, but in other cases I’ve been out of luck. If you don’t know what kind of plastic it is, you can’t know whether it could potentially be harmful or not. To be on the safe side, I would stop using anything without a plastic number on it in favor of an equivalent product that does.
If you have additional questions about safe plastic numbers and unsafe ones, add them to the comments below and I will try to address them there or in a future blog post!