The 3 Plastics Every Parent Should Avoid

Repeat after me: 3, 6, 7.
Plastics that fall into the 3, 6 and 7 categories are composed of chemicals that carry the greatest risks.
Plastics that fall into the 3, 6 and 7 categories are composed of chemicals that carry the greatest risks.
Taborsk via Getty Images

Plastic has infiltrated pretty much every aspect of our children’s lives. They wear it, eat and drink from it, and teethe and sleep on it. During the early years, even their butts are wrapped in, and wiped with, it.

The indestructible material is convenient, but it also has a bad rap ― and for good reason. It’s known to leach, which means if it’s heated or scratched, the chemicals in it can wind up in food, or directly in a baby’s mouth, if he sucks strongly enough on it. Some of these chemicals are associated with a host of scary risks. They could increase the risk of cancer and infertility and affect brain development, among other issues. But we don’t really know the full extent of how this constant exposure to plastic will affect children in the long term.

Still, even if we want to, it’s nearly impossible to completely eliminate plastic from their lives. I know, because I’ve tried. I have two sons ― one’s 3 and the other is 10 months. Good luck trying to find your kids’ favorite snacks that aren’t packaged in the clear, flimsy stuff. (I’m looking at you, basically every brand of crackers!)

But parents aren’t totally powerless. There are things we can do to limit our kids’ exposure to potentially harmful ingredients in plastics, according to Dr. Aparna Bole, a pediatrician and member of the American Academy of Pediatrics’ Council on Environmental Health Executive Committee.

“It’s tempting to just throw up your hands,” said Bole, acknowledging the overwhelming amount of confusing information about plastics and the lack of clarity in product ingredients.

We asked her to outline one simple action parents can take to rid their homes of the most worrisome types of plastics. What she told us was surprising.

Bole recommends getting into the habit of peering at the bottom of plastic products to see which recycling category they fall into. You’re looking for a teeny, barely there triangle with a number in the center of it. The digits you want to avoid are 3, 6 and 7. (You might want to even get into the habit of chanting the three numbers in your mind to commit them to memory.)

These three are made up of chemicals that are considered most concerning when it comes to toxicity. (Products labeled with “greenware” or “biobased” are likely free of certain chemicals but aren’t necessarily completely safe.) For the plastic products that aren’t labeled with a number, it’s simply impossible to know what’s in, or not in, them.


You’ll typically find No. 3 stamped on teething rings, toys, plastic curtains, take-out packaging and personal care products. These items are made from polyvinyl chloride (generally referred to as PVC) and of concern is the release of phthalates, a binding agent that makes the plastic malleable and is in an innumerable amount of consumer products, not just plastics. The most common fear is that certain phthalates may act as endocrine disruptors affecting reproductive hormones, based on studies done in rodents. There are many types of phthalates, some of which are banned for use in toys and child care products such as teething rings due because they could affect male genital development.

Researchers are looking into whether phthalates could increase childhood obesity (results aren’t conclusive) and contribute to cardiovascular disease. Early exposure to phthalates, which are restricted in Europe, may also be linked to neurodevelopmental and behavior problems in young children.

No. 6 items are made of polystyrene and include disposable plates and cups (like those red Solo party cups!), meat trays, egg cartons and take-out containers. When heated, they can release toxic materials such as styrene, which can be absorbed in the digestive tract. Styrene has been linked to headache, fatigue, dizziness, confusion and other issues in factory workers who inhale massive quantities on a regular basis. There isn’t research to show negative health effects on adults or children who may be exposed orally at low concentrations. (Styrene is also found in cigarette smoke and released by photocopiers.)

No. 7, the “miscellaneous” category, is usually a mixture of plastics. This number is found on baby bottles and in 3-gallon and 5-gallon water bottles. Some of these items contain bisphenol A (BPA), an industrial chemical that could disrupt the body’s hormone system.

While kids are more vulnerable to these risks because their bodies are still developing, Bole said it’s a good rule of thumb for everyone to avoid eating off materials that fall into those three categories.

(I did an extensive search in my house, flipping over products and squinting into the light to figure out what category each item fell into. I found a number of things in my kitchen that bore the dreaded 3, 6 and 7 labels, including items I didn’t expect, such as a measuring cup I’ve been using for five years.)

In addition to avoiding those three types of plastic, Bole also advises against microwaving any plastic altogether, even if it has the “microwave safe” label on it. The flimsier the plastic feels, the worse it is to pop it into a microwave. Ideally, we shouldn’t even be putting plastic into the dishwasher. (For extra credit, Bole also suggested not putting warm or hot liquid in a plastic cup or bottle. This comes up a lot when warming up breast milk and formula, which she recommends doing in a glass bottle if possible.)

Causing plastic to get hot is an issue because it can lead the material to break down and leach chemicals such as BPA and phthalates, which are considered “endocrine disruptors.” Migration of these chemicals is likely to be greater with fatty foods, including meats and cheeses, than with other foods.

When possible, swapping out plastic for other materials is also a good move. Using stainless steel plates and cups, for example. Or storing food in glass containers instead of plastic ones.

Bole lamented that consumers have to do this type of investigation, noting that these worrisome chemicals shouldn’t be included in products in the first place. It can seem intimidating, she said, and you may not be able to fully protect yourself from these ubiquitous ingredients. But arming yourself with the available information is a place anyone can start.

“You can get paralyzed,” Bole said of trying to decode all of the information surrounding the risks associated with plastics. “But there are a few very simple ways that everyone can make healthier choices.”

This story is part of a series on plastic waste, funded by SC Johnson. All content is editorially independent, with no influence or input from the company.