Every plastic item carries a small number in a chasing arrow symbol that indicates its resin type. Learning plastic numbers to avoid helps you reduce hidden chemical risks and improve recycling outcomes. This guide highlights which resin codes are most controversial and which safer alternatives to choose instead.
Some plastics are linked to hormone disruption, microplastic shedding, and difficult-to-recycle formats. Focusing on the resin codes most likely to cause concerns allows you to make practical, lower risk choices for daily use.
| Plastic Number | Resin Name | Typical Use | Key Concerns |
|---|---|---|---|
| 3 | PVC | Food wrap, pipes, blister packs | Additives like phthalates, dioxin risk when heated |
| 6 | PS | Disposable cups, trays, egg cartons | Potential styrene migration, brittle and poorly recycled |
| 7 | Other | Mixed bottles, sport bottles, electronics | May contain BPA or unknown newer polymers |
| 1 | PET | Beverage bottles, jars | Single use only, may leach antimony over time |
Understanding Plastic Resin Identification Codes
What the Numbers Mean
The resin identification code, a number inside a chasing arrow, classifies the polymer type. Each number corresponds to specific behaviors in processing, durability, and recycling. Knowing which plastic numbers to avoid is based on how these resins behave when heated, reused, or discarded.
PVC (Plastic Number 3) Risks and Alternatives
Hidden Additives and Environmental Impact
PVC often requires plasticizers and stabilizers that can migrate into food or dust. These additives, including phthalates, raise concerns for endocrine disruption and environmental persistence. Limiting flexible PVC in food contact and daily use items is a practical step.
Polystyrene (Plastic Number 6) Safety Considerations
Microplastic Shedding and Food Contact
Polystyrene can release styrene, especially with hot or fatty foods, and breaks into small particles easily. Its low recycling rate and tendency to fragment make it a resin code many experts recommend avoiding for regular food contact. Switching to reusable containers lowers both chemical and microplastic exposure.
Other Plastics (Plastic Number 7) and Emerging Concerns
BPA, BPF, and Unknown Polymers
Number 7 covers blends and newer plastics where long term data may be limited. Some products labeled Other contain BPA or BPF, chemicals of concern for hormonal systems. Choosing clearly labeled safer materials, like specific PET or high density polyethylene, reduces uncertainty.
Key Takeaways and Practical Steps
- Memorize the most problematic plastic numbers to avoid: 3, 6, and 7.
- Prefer food contact materials with known safer resins such as PET or high density polyethylene.
- Avoid reheating food in takeout containers and reduce single use patterns.
- Check product labels and certifications to confirm material transparency.
- Replace older kitchenware that may contain unmarked or legacy plastics.
FAQ
Reader questions
Is it safe to reuse PET bottles multiple times? Repeated washing and heating can increase leaching of antimony and other breakdown products from PET, so single use is the safer approach for this resin. Are products labeled PS microwave safe?
Most polystyrene containers are not designed for microwave heating and can warp, crack, or release more styrene when exposed to high temperatures.
Can PVC be found in children’s products?
Flexible PVC is sometimes present in toys or flooring where plasticizers are used, so checking materials and certifications helps limit unnecessary exposure.
What should I do with containers marked Plastic Number 7?
Check specific resin details on the packaging, avoid heating or harsh dishwashing, and prefer alternatives with clearer, safer resin codes when possible.