Which plastics are safe? I get that question all the time. The Internet is full of charts listing the numbers of the various types of plastic and explaining which ones are safe and which ones are not. Supposedly, #2 (high density polyethylene), #4 (low density polyethylene), and #5 (polypropylene) are safe, right? Does that mean the lid on my travel mug is safe? It’s #5 polypropylene.
So is the sport cap on Michael’s Klean Kanteen water bottle.
We’re supposed to avoid plastics #3 (PVC), #6 (polystyrene), and #7 (polycarbonate). Polycarbonate is the plastic that is made from the chemical Bisphenol-A (BPA). And BPA has a bad rap because it’s a hormone-disruptor. Walk down the aisles of any drug store these days, and you’ll find rows of plastic products labelled BPA-Free. BPA-Free water bottles…
In fact, entire shelves of baby products are labelled BPA-free. Are they safe?
Plastic #1 (polyethylene terephthalate), the type of plastic that disposable water bottles are made of, is not made with BPA either. Is it okay to drink from?
My response: we can’t be sure any plastic is safe as long as we don’t know what chemicals are in the plastic and as long as those chemicals have not been tested. I’ve said this over and over again. And I’ve pointed out chemical additives that have been found to leach from “safe” plastics like polypropylene.
Now, a University of Texas study published last month in Environmental Health Perspectives confirms that hormone-disrupting chemicals leach from almost all plastics, even BPA-free plastics.
That study? Is 33 pages. I read the whole thing, so you don’t have to.
BPA is not the only chemical with Estrogenic Activity
BPA concerns us because it has Estrogenic Activity (EA), meaning it mimics the hormone estrogen in the body. According to the study authors, chemicals with EA have been linked to all kinds of health problems, including
early puberty in females, reduced sperm counts, altered functions of reproductive organs, obesity, altered sex-specific behaviors, and increased rates of some breast, ovarian, testicular, and prostate cancers.
Theorizing that BPA was not the only EA chemical, the authors of the study tested 455 everyday products of all different kinds of plastic from various retail sources to determine if they had estrogenic effects. Products included food wrap, deli containers, hard or flexible packaging, plastic bags, baby bottles, and reusable plastic water bottles. Most of these products were BPA-free. But what other chemicals were in them? Just like you and I, the researchers didn’t know. We are, after all, talking about the plastics industry and their secrets.
The exact chemical composition of almost any commercially available plastic part is proprietary and not known. A single part may consist of 5-30 chemicals, and a plastic item containing many parts (e.g., a baby bottle) may consist of 100 or more chemicals, almost all of which can leach from the product, especially when stressed.
So, to test the products they had gathered, the researchers first extracted chemicals from the various plastic products using different solvents to mimic the types of foods/beverages the plastics might contain, and then they exposed those extracted plastic chemicals to MCF-7 cells, a type of human breast cancer cell that is receptive to estrogen. If the cells multiplied in the presence of the leached plastic chemicals, the researchers knew those chemicals were estrogenic and therefore potentially harmful to humans.
Their finding? Almost all of the plastic products tested leached EA chemicals.
Almost all commercially available plastic products we sampled, independent of the type of resin, product, or retail source, leached chemicals having reliably-detectable EA, including those advertised as BPA-free. In some cases, BPA-free products released chemicals having more EA than BPA-containing products.
Stressed Out Plastic is Even Worse
Realizing that plastics are more likely to leach chemicals when exposed to various stressors like heat or light, the researchers also tested the products after subjecting them to UV radiation (mimicking the effect of sunlight), wet heat (as in a dishwasher), and microwave radiation. As you might expect, there was more leaching of EA from stressed plastic products than from unstressed ones. In fact, in some cases, products with no detectable EA levels when unstressed were found to release EA chemicals after being roughed up a bit. Wouldn’t you?
The Point: it’s not enough for a company to test its products in an unstressed environment. Only by exposing plastic products to the kinds of stressors it will be subjected to in real life can we know for sure whether it will leach EA chemicals or not.
Bio-Based Plastics Like PLA are Not Exempt
PLA is a kind of compostable plastic made from starch, usually corn. It’s generally touted by its manufacturers as safe simply because it doesn’t come from petroleum. So guess what. 71% of all the PLA samples tested were found to leach EA chemicals as well.
The Point: just because a plastic is made from plants doesn’t make it safe.
It’s in the Additives
The researchers also tested “barefoot” polymers, meaning pellets of the basic plastic before any other chemicals have been added to it. And while a few of these barefoot plastics (#2, #4, and #5) did not leach EA chemicals by themselves, nearly all commercial products made from these plastics did. It’s those darned secret additives!
The Point: it’s not enough for a company to tell you that a certain type of plastic (#2, #4, #5) is safe. Without knowing what additives are in it, we don’t know what could be leaching out.
Some BPA Replacements are WORSE than BPA
The researchers tested baby bottles made from PES (polyethersulfone), a new plastic being used to replace BPA in hard plastic bottles. Among others, Born Free brand bottles are made from PES. What did they find? Some PES baby bottles released more EA chemicals than those with BPA in them!
The researchers also tested water bottles made from PETG, a copolyester like the new Eastman Tritan which has replaced BPA water bottles. Again, EA chemicals were found to leach from those bottles as well.
As for our good old #1 PET disposable water/soda bottles? Big time EA leaching.
The Point: be skeptical of new plastics being developed to replace harmful ones. And remain skeptical of old plastics too.
Are There Any Safe Plastics?
One of the study researchers works for a company called PlastiPure, which is working to develop EA-free plastics. To do that, the company hopes to create an EA-free supply chain, requiring that all the chemicals that are added to plastics be certified EA-free as well. Their WaterGeeks plastic water bottle is advertised as EA-free.
I had a conversation with Brent Meikle from PlastiPure last year. I asked why go to all the trouble to develop a “safe” plastic bottle when they could just promote stainless steel or glass instead. Brent’s feeling was that it was not practical to expect everyone to switch to stainless steel bottles, especially those involved in sports, and that plastics are here to stay, so they should be safe.
Whether or not the new EA-free plastics are safe or whether they will turn out to have other harmful health effects, the fact remains that like all petroleum-based plastics, they are not biodegradable and will cause harm to the environment when not handled properly. I hope that PlastiPure will continue to focus on making durable plastic products rather than single-use disposables.
As for me, I’m going to stick to my stainless steel travel mug and water bottle. No plastic water bottles for me. But as for my plastic lid? If it has to be plastic, I’d rather it were EA-free.
The Point: we can only act on the information we have at the moment. Ask questions. Remain skeptical. But keep an open mind.
This post is included in the March 2012 Green Moms Carnival on toxic chemicals hosted at Groovy Green Livin’.