Polypropylene
PP / resin identification code 5
Storage containers, lunch boxes, baby bottles, caps. A study found more particles released when heated.
Main uses
- Microwave-safe storage containers and lunch boxes
- Plastic bottle caps
- Plastic baby bottles
- Some tea bags
- Takeout containers
- Cutting boards
Found in food, water and the human body
- Preparing formula in polypropylene baby bottles released up to 16.2 million particles per liter, increasing with temperature (Li et al. 2020)
- In bottled water, 54% of the particles confirmed by FTIR (Mason et al. 2018; matched the cap material)
- Human stool: found in all 8 people, with polypropylene and PET the most common (Schwabl et al. 2019)
- Placenta: the 3 particles identified as a polymer were colored polypropylene (Ragusa et al. 2021)
- Cutting boards: released more than polyethylene boards (Yadav et al. 2023)
- On the other hand, a study testing containers with 100°C hot water found nothing from polypropylene containers under any condition (Caponigro et al. 2025)
Detailed numbers by food: Baby bottles and formula preparation, Microwave heating and takeout containers, Cutting boards, Electric kettles and kettles, Bottled water, Tea bags
Evaluations of raw materials and additives
- Polypropylene itself is IARC Group 3
IARC classifications rate the strength of evidence that something can cause cancer, not the size of the risk at everyday amounts.
Japan's standards (utensils, containers and packaging that touch food)
- MHLW Notification No. 370: same standard as polyethylene
- Positive list material category 2
General standards for all synthetic resins: cadmium and lead in the material 100 μg/g or less each, heavy metals migrating (as lead) 1 μg/mL or less, and others. Since June 2020, synthetic resins that touch food have been under a “positive list system” that sets which substances may be used (the transition period ended May 31, 2025). → Rules and regulation
Production in Japan
| Item | 2023 | 2024 | 2025 |
|---|---|---|---|
| Polypropylene | 2,075,387 t | 1,934,738 t | 2,037,468 t |
Compiled by the Japan Plastics Industry Federation (based on METI's production statistics). This is the amount made in Japan, not the amount used in Japan.
Sources
- Li D, et al. Nature Food 2020;1:746-754 (PMID 37128027)
- Mason SA, et al. Front Chem 2018;6:407 (PMID 30255015)
- Schwabl P, et al. Ann Intern Med 2019;171:453-457 (PMID 31476765)
- Ragusa A, et al. Environ Int 2021;146:106274 (PMID 33395930)
- Caponigro V, et al. Food Chem 2025;464:141716 (PMID 39447258)
- Consumer Affairs Agency, standards for utensils, containers and packaging (Notification No. 370, Part 3) (Japanese)
- IARC List of Classifications
- Japan Plastics Industry Federation, statistics (Japanese)
Last checked 2026-10-01. This page is a translation of our Japanese page; if they differ, the Japanese page is the reference.