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What is Plastic Number 6 and Is it Safe for Babies

What is Plastic Number 6 (PS) and Is it Safe for Babies?

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The amount of plastic we use in the world today makes it difficult to figure out which types are safe and which ones we should avoid. With that in mind, I thought it would be helpful to cover all of the different plastic numbers and go into the details of each. Today, we’re talking about plastic number 6 (PS) to see what it is and whether or not it is safe for babies.

Plastic number 6 (Polystyrene or PS) is found either as a solid plastic or foam material prized for its insulating properties. Although approved by the FDA for foodservice, it has been shown to leach dangerous chemicals, such as styrene, into food and beverages, especially when heated.

Unfortunately, we still have to worry about some of the plastics out there in the marketplace and plastic number 6 is one of these. Let’s work through what polystyrene is, where we are likely to find it, and how safe it is for babies to be exposed to it.

What does plastic number 6 mean?

If you are paying attention, you’ve seen the little numbers and triangular recycling symbol on the bottom of food containers, but you probably aren’t sure what they mean. These numbers, called resin identification codes (RIC), are there to tell recyclers what kind of material they have so they will know how to process it. They are helpful to us as consumers as well because otherwise, we wouldn’t know what kind of plastic we are dealing with!

Plastic items with a number 6 on the bottom are made of polystyrene, or PS, which is made by stringing together styrene. It is most often made into a foam material called expanded polystyrene (EPS) or extruded polystyrene (XPS) which is almost entirely air. EPS and XPS have an incredible insulating ability and buoyancy, but they are also very brittle and break easily. This type of plastic is frequently found in food and beverage service applications.

The codes on food and beverage containers are there because the FDA is quite strict about what kinds of materials can be used to store and otherwise make contact with the food we eat, but they aren’t typically required to be listed anywhere else. The American Society for Testing and Materials (ASTM International) is responsible for maintaining these plastic standards, but there is no regulatory body in charge of making sure all plastics in the marketplace are listed. If you aren’t sure what kind of plastic you are dealing with in your baby toys and accessories, your best bet is to check the original packaging or call the manufacturer to be sure.

Examples of plastic number 6

Although polystyrene was originally discovered back in 1839, it reached mainstream success and adoption in 1944 with Dow Chemical’s introduction of Styrofoam. Dart Container, the current largest maker of foam cups, shipped their first delivery in 1954 with a similar product made from EPS. It’s estimated that millions of pounds of this particular plastic are produced each year which, considering that the products are mostly air and very lightweight, is way more than it sounds like.

In general, you’ll find plastic number 6 in things like:

  • CD ‘jewel’ cases
  • Petri dishes, test tubes
  • Surfboards
  • Boat docks
  • Disposable razors
  • Packing peanuts
  • Molded packaging foam
  • Electronics
  • Automobile parts

Essentially, polystyrene is used anytime a cheap plastic is needed (such as a disposable razor) or when the insulating or buoyant properties of EPS and XPS are needed. Since it is so cheap to produce, it has found its way into many different products over the years.

Food containers made from polystyrene

A material that is cheap, light, and offers great insulation seems to be a perfect match for products like takeout containers and other disposable food service items. In fact, you’ll find them all over the grocery store in things like:

  • Disposable cutlery, cups, and some plates
  • Egg cartons
  • Foam ‘clamshell’ leftover boxes
  • Meat and poultry trays

Is plastic number 6 reusable?

Yes, but you might not want to.

Assuming that you have not heated, melted, or otherwise damaged polystyrene it can be reused several times. In foam form, polystyrene would be difficult to clean though. You would most often see things like plastic cups reused before being discarded.

We’ll explain more later, but there is solid evidence suggesting that polystyrene might not be as safe for holding food as we think so there are better options.

Is plastic number 6 biodegradable?


In fact, it is estimated that products like Styrofoam could last in a landfill setting for literally 1 million years.

A million years.

What’s worse, this material will leach many different harmful chemicals into the ground and water around over time, especially styrene. When floating in environments such as oceans and rivers, polystyrene actually breaks down quite quickly because of sun exposure. While this might sound good, it’s actually bad for the marine biosphere because it breaks into a fine powder that can be absorbed and ingested by wildlife.

Can you recycle polystyrene?


Polystyrene is 100% recyclable, but most curbside pickups won’t take it because it is mostly air. Also, just because something is recyclable, doesn’t mean that it is actually happening.

Much of the polystyrene that finds its way to recyclers doesn’t actually get recovered. In fact, much of it gets shipped overseas to be melted into other plastics or simply burned as fuel – probably to make more plastic! There is not a lot of demand for this kind of plastic in the recycling community, unlike some other plastics, because there aren’t a lot of post-consumer uses for it.

Unfortunately, this means that a lot of polystyrenes, especially the EPS and XPS versions, simply end up in the landfill in the US. Because it breaks up so easily, it’s also commonly found in waterways and beaches, having been blown around easily by the wind.

Baby products made from polystyrene

Aside from the general use for polystyrene, there are a few baby-specific items that you’ll find plastic number 6 used in:

  • Disposable plates and cups
  • Reusable plastic sippy cups and lidded cups
  • Model kits
  • Figurines

Similar to other plastics, polystyrene is often used because it is cheap and easy to manufacture, keeping costs low for toy manufacturers and consumers. For years I only associated polystyrene with foam takeout containers, but once I started looked around I realized that several of my children’s cups were actually labeled plastic number 6. This scared me a little bit because I’m sure I’ve thrown a few of those in the dishwasher at one point or another, potentially causing problems with styrene leaching out.

Since toys aren’t usually required to list what types of plastics they are using, be sure to check the packaging and don’t be afraid to check the website or call the manufacturer to be sure that they are safe. In most cases, responsible companies will go out of their way to explain what kind of materials they are using and why they are safe.

Don’t leave it up to chance!

Is plastic number 6 (PS) safe for babies?

Like I mentioned before, the biggest issue with polystyrene is that it can leach styrene into food and beverages, especially when heated.

With this in mind, do not ever heat up food inside a polystyrene container or pour hot liquids into them. In addition to styrene, there are other chemicals that can leach out of this plastic as well because it is not as chemically stable as other plastics.

While there are other issues of concern, polystyrene doesn’t actually contain BPA which is the most publicized bad guy in the world of plastic. Still, just because a shark is missing a tooth doesn’t make him any less dangerous!

Can you microwave polystyrene?

No! Don’t do it!

Microwaving this type of plastic will heat it up to the point where it releases styrene and other chemicals into whatever is inside it (food and beverages) as well as the air around it. In fact, foam versions of polystyrene (EPS and XPS – aka Styrofoam) will actually melt in the microwave pretty quickly. Having melted plastic in or around your food is seriously bad news.

Finding alternatives to plastic for your baby

With the issues surrounding plastic number 6, I would highly recommend trying to avoid it whenever possible. Not only does it pose an immediate health risk through chemical exposure, but it’s also incredibly harmful to the environment – especially marine life. Since it’s made from petroleum, you also have to consider all of the other chemical by-products and side effects of the oil and gas industry. In the long run, they are harmful to the environment and planet as well.

It’s probably impossible to completely avoid plastics, but there are many ways that you can introduce other items into your house that will make great substitutes, last longer, and keep your baby and the environment safer!

Stainless steel cups and utensils

By purchasing stainless steel items for your baby, you’ll be making a long-term investment in things that will last for years and years. They are dishwasher-safe, oven-safe, fridge-safe, and more! Of course, you won’t be able to microwave them, but that’s a small price to pay! They will also definitely hold up to a baby or toddlers rough eating style!

Here are a few options:

  • Stainless steel divided trays – These might look a little strange,  but they will get the job done without the worry of anything leaching into your food! You get three in a pack so you’ll have multiple meals covered. Each tray also has 5 compartments to keep food separate for picky (or messy!) eaters. There are also optional lids as well. stainless steel plateware
  • Stainless steel utensils – Keeping it simple with the utensils. These are 100% stainless steel with cute designs etched in the handles. Each set comes with 4 knives, forks, and spoons.
  • Pura Kiki Stainless steel infant bottle/sippy cups – I’ve recommended these before and I’ll keep doing it! This is a nice starter set that includes two stainless steel bottles, low flow nipples, medium flow nipples, sippy cup spouts, and travel lids. You’ll be able to start off on the right foot with this set and it will last you into the toddler years!

Learn more about the other plastic numbers

We’ve covered a lot of ground when it comes to plastic number 6, but there are a total of seven plastic numbers that you need to know about. Check out my next article in the series all about plastic number 7. This is a weird category that you need to understand in order to stay safe!

Joshua Bartlett
Joshua Bartlett

My name is Joshua Bartlett I run this blog with my wife Jarah. We have more than 11 years of parenting experience including three girls and one boy. I started this blog in late 2018 when I realized that I was dealing with baby-related issues on a constant basis…please read more about me here!

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