What to Know About the Toxicity of Polypropylene

Written by WebMD Editorial Contributor
Medically Reviewed by Shruthi N, MD on January 22, 2025
4 min read

Plastic has many uses in our everyday lives. You may think that plastic is safe for your health because of its widespread availability. However, some kinds are not. With many different plastic compounds available, how do you know what’s safe for your health and what isn’t?

Polypropylene is a type of plastic used to make everything from yogurt containers to water bottles. It's easy to recycle and is one of the most popular plastics used today.

You'll know a piece of plastic is made of polypropylene if it has the number 5 inside the recycling triangle symbol.

Polypropylene is commonly used in many different applications, including: 

Packaging materials. Polypropylene is super strong and inexpensive, making it ideal for pallets, bottles, yogurt containers, beverage cups, and other packaging containers.

Housewares. Polypropylene is one of the most common plastics used to make consumer goods, such as plastic furniture, appliances, luggage, and toys. 

Automotive parts. Because of its cost and pliability, polypropylene is often used to make automotive parts such as battery cases, bumpers, interior and door trim, and instrumental panels.

Medical applications. Polypropylene is resistant to chemicals and bacteria. So, it's very popular for medical uses, including syringes, food trays, bed pans, Petri dishes, and pill containers.

Polypropylene doesn't contain bisphenol-A (BPA), which is a chemical used to make hard plastics. BPA has been used in food packaging since the 1960s.

Research shows that BPA leaches from plastic containers, plates, and bottles into food when they're heated. And that's not good because once BPA gets in your body, it acts like the hormone estrogen, which can cause various health problems, including an overacting immune system, potential infertility and early puberty, and higher chances of cardiovascular disease.

Look for plastic products with a “BPA-free” label, and be aware that plastics marked with recycle codes 3 or 7 may contain BPA. You should never microwave plastic if it can be avoided.

No, polypropylene doesn't contain phthalates. Phthalates are another group of chemicals used since the 1930s in plastics. They help soften them, making them more flexible and stronger. But research has now shown that phthalates are bad for your health because they can act as endocrine disruptors. This means exposure to phthalates can damage your endocrine system. Phthalates can be found in everything from tablecloths and furniture upholstery to food packaging and cosmetics.

You may be exposed to phthalates through:

  • Food ingestion 
  • Inhalation
  • Drinking contaminated water 
  • Absorption through skin

Polypropylene is generally considered safe for use. It's approved by the FDA for both single and repeated-use food containers. It's also considered a safe plastic by the EPA. No studies have shown a direct correlation between polypropylene and cancer in humans. But we need a lot more research on polypropylene microplastics and how they affect not just our bodies, but also the environment.

Polypropylene is a better plastic alternative than those containing BPA. But when it comes to other benefits of polypropylene, there are many to consider, including:

  • Lightweight
  • Strong but flexible
  • Inexpensive to make
  • FDA-approved for food use
  • Heat-resistant and durable
  • Recyclable

While polypropylene is generally safe to use, it does have a few disadvantages, including: 

  • Becomes brittle at extremely low temperatures 
  • Deteriorates in the sun
  • Doesn't biodegrade

The biggest risks to your health from polypropylene plastics may come from microplastics. Studies on different-sized microplastics in humans are very limited. But one study did find that irregular-shaped polypropylene microplastics can affect human breast cancer cells by driving the cancer's progression. This is one of the first studies to show how microplastics can affect breast cancer in humans.

You can use polypropylene products safely by following a few simple rules. 

  • Use BPA-free plastic products only.
  • Don't heat your food in plastic products.
  • Toss any plastic older than 2012 because it almost certainly has BPA.
  • Don't reuse any plastic containers or water bottles with the recycling code 1.
  • Don't give your baby (or pets) plastic toys to chew on.

In general, opt for glass containers when you can, for storing and serving food.

 

Polypropylene is a type of plastic used to make everything from food containers and water bottles to household appliances and automotive parts. It's inexpensive to make and strong. It doesn't contain BPA and is recyclable, so it's a good plastic option. However, use it in limited amounts, as new studies show that polypropylene microplastics may be harmful to your health.

Is polypropylene a fabric or plastic?

Polypropylene is actually a flexible plastic that can be used to make yarns and fibers, which can be manufactured into all types of fabrics, including woven polypropylene, knitted fabric, and nonwoven fabrics.

Is polypropylene biodegradable? 

No. Polypropylene will not biodegrade in the environment. 

Is polypropylene recyclable?

Yes. Polypropylene is recyclable. It's melted and then used to make other new plastics. To identify it, look for the number 5 recycling symbol.