Polypropylene is the second-most widely produced commodity plastic (after polyethylene) and it is often used in packaging and labeling.
Polypropylene is very similar to polyethylene but has greater resistance to heat, which is why it is often used for food packaging and food storage bags and containers.
Is Polypropylene Safe?
Polypropylene is considered one of the safest plastics.
According to its Safety Data Sheet, polypropylene has not been found to be carcinogenic by several safety organizations including the International Agency for Research on Cancer (IARC) and the Occupational Safety and Health Administration (OSHA).
Not all polypropylene, however, is created equal. Plastics are often made with fillers, plasticizers, and additives to enhance their functionality.1. A single plastic product can contain dozens of added chemicals. Polypropylene is less likely than many other plastics to contain fillers, plasticizers and additives but they may still be present. Unfortunately, without better disclosure from manufactures about the content of specific plastic materials we can only speak about toxicity and safety in general terms.
Does Polypropylene Offgas?
Polypropylene, sometimes referred to as Olefin, does offgas but generally at a much lower rate than more toxic plastics such as PVC and polystyrene.2
It is often used to make medical equipment and to store museum collections because of its relatively low level of emissions.
Does Polypropylene Leach into Food and Drink?
While polypropylene is relatively stable, and it is generally considered a safer plastic for food and drink, it has also been shown to leach plastic additives. In one study, pure polypropylene resin did not leach any endocrine disrupting chemicals but common food containers made with polypropylene did.3 Leaching from plastic food containers is increased with heat, duration of contact, and acidity of the food or drink. So, consider how the item is being used and how you will be exposed to it. For example, a water bottle made of polypropylene that has only brief contact with the water is less likely to leach than a container used to store hot tomato soup.
Avoiding any plastic is ideal because it not only poses risk to human health but it is harmful to the environment. But, if you must use products made with polypropylene, the risk of exposure is probably low.
1John N. Hahladakis, Costas A. Velis, Roland Weber, Eleni Iacovidou, Phil Purnell. An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. Journal of Hazardous Materials. 2018; volume 344; pages 179-199. License.
2Even M, Girard M, Rich A, Hutzler C and Luch A (2019) Emissions of VOCs From Polymer-Based Consumer Products: From Emission Data of Real Samples to the Assessment of Inhalation Exposure. Front. Public Health 7:202. doi: 10.3389/fpubh.2019.00202
3John N. Hahladakis, Costas A. Velis, Roland Weber, Eleni Iacovidou, Phil Purnell. An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. Journal of Hazardous Materials. 2018; volume 344; pages 179-199. License.; McDonald GR, Hudson AL, Dunn SM, et al. Bioactive contaminants leach from disposable laboratory plasticware. Science. 2008;322(5903):917. doi:10.1126/science.1162395