Plastic Recycling Numbers 1-7 Ranked: Microplastic & Chemical Safety
Last reviewed: by the MicroPlastics Research Desk. Submit a correction or see our editorial standards.
Quick Answer
Different container in your kitchen? Scan it for the polymer, a 0–100 risk score, and a safer swap.
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Key Takeaways
- The recycling number (1-7) is not a safety rating, it's a resin identification code for sorting.
- Safer for food: #2 HDPE, #4 LDPE, #5 PP.
- Acceptable but degrades with heat: #1 PET (single-use only, never refill or reheat).
- Avoid for food: #3 PVC, #6 polystyrene (styrofoam), #7 (Other, often polycarbonate / BPA).
- Even the “safest” plastics shed microplastics with heat, UV, acidity, and physical wear. Glass and stainless steel are the only zero-microplastic options.
The full ranking
| Safety rank | # | Resin | Common products | Main concern |
|---|---|---|---|---|
| 1 (safest) | #5 | Polypropylene (PP) | Yogurt cups, takeout containers, straws, bottle caps | Lowest leaching of common plastics. Some particle shedding under microwave heat. |
| 2 | #2 | High-density polyethylene (HDPE) | Milk jugs, juice bottles, detergent bottles | Considered low-risk; does shed micro/nanoplastic with UV exposure. |
| 3 | #4 | Low-density polyethylene (LDPE) | Plastic bags, cling wrap, squeeze bottles | Low chemical leaching; sheds fibres in food contact and laundry. |
| 4 | #1 | Polyethylene terephthalate (PET, PETE) | Water bottles, soda bottles | Antimony leaching under heat; major microplastic source when reused or warmed. |
| 5 (avoid where possible) | #7 | Other (mixed; often polycarbonate, BPA, BPS) | Reusable water bottles (older), 5-gal water jugs | Often contains BPA or replacement bisphenols (BPS, BPF), known endocrine disruptors. |
| 6 (avoid) | #3 | Polyvinyl chloride (PVC) | Cling wrap, food packaging films, pipes | Releases phthalates and vinyl chloride. PVC microplastics implicated in NEJM 2024 cardiovascular study. |
| 7 (avoid) | #6 | Polystyrene (PS, Styrofoam) | Takeout containers, cups, meat trays | Releases styrene (IARC possible human carcinogen). High particle shedding under heat or contact with hot/oily food. |
Why the recycling symbol doesn't mean what you think
The triangle of arrows with a number inside is a Resin Identification Code (RIC), introduced by the plastics industry in 1988 to help sorters at recycling facilities. It is not a safety rating, an indicator of recyclability in your community, or a guarantee that the item was made from recycled material.
In practice, only #1 PET and #2 HDPE are widely recycled in most US and EU municipal programs. #3-#7 are rarely accepted at curbside recycling regardless of the symbol.
Each plastic explained
#1 PET / PETE. Polyethylene terephthalate
The most common single-use food and beverage plastic. Considered food-safe for single use but problematic when reused or exposed to heat. PET releases antimony trioxide (a manufacturing catalyst) at elevated temperatures, and is the dominant material in the 2024 Columbia/Rutgers nanoplastic study of bottled water (240,000 particles/L).
#2 HDPE. High-density polyethylene
Stiff, opaque plastic used for milk jugs, juice bottles, and detergent bottles. One of the lower-leaching food plastics. Still degrades over years of UV exposure and sheds microplastic from wear.
#3 PVC. Polyvinyl chloride
Avoid for food contact. PVC requires phthalate plasticisers to be flexible, and these plasticisers are known endocrine disruptors that leach into food, especially fatty or hot food. PVC was also detected in 12% of carotid plaque samples in the NEJM 2024 cardiovascular study.
#4 LDPE. Low-density polyethylene
Soft, flexible plastic used for shopping bags, bread bags, and cling film. Low chemical leaching, but a major contributor to microfibre and microparticle shedding into food and into the environment.
#5 PP. Polypropylene
Generally considered the safest of the common food plastics. Heat-tolerant (microwave-rated for many products) and chemically stable. Stillsheds microplastics when microwaved, a 2023 University of Nebraska study found a single PP container could release millions of particles per microwave cycle.
#6 PS. Polystyrene
Avoid for food contact. PS releases styrene under heat or oily food contact; the International Agency for Research on Cancer classifies styrene as a possible human carcinogen (Group 2A as of 2019). Expanded polystyrene (Styrofoam) is especially friable and sheds particles readily.
#7. Other (often polycarbonate)
A catch-all category. Older #7 items, especially 5-gallon water cooler jugs and some reusable bottles, are polycarbonate, made with bisphenol A (BPA), a known endocrine disruptor. “BPA-free” alternatives often use BPS or BPF, which have shown similar hormonal activity. See our BPA-free guide for the full picture.
Quick rules of thumb
- Never microwave anything in plastic, even #5.
- Never put hot food or liquid into #6 polystyrene.
- Don't reuse #1 PET water bottles.
- Avoid #3 PVC and #7 polycarbonate for food contact entirely.
- For food storage, glass or stainless steel beats every plastic.
For full reduction strategies see microplastics in plastic containers and worst microplastic ingredients.
What the MicroPlastics app checks
- Material, stainless, glass, ceramic, cast iron, plastic (PE / PP / PS / PVC), silicone, wood.
- Visible condition, scratches, chips, warping, fade.
- Brand and product line, flags for non-stick / PFAS-treated items.
- Use-context flags you log, heat exposure, dishwasher cycles, contact with hot or fatty food.
- Cited published research behind the 0–100 risk score.
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Scan kitchen and household products before buying
Cookware, food storage, cutting boards, accessories. The app weighs material, condition, brand, and use-context to give a 0–100 risk score per item.
Scan household items in the appFrequently Asked Questions
What plastic numbers are safest for food?
Which plastic numbers should you avoid?
Is plastic #5 safe to microwave?
Is plastic #1 PET safe for water bottles?
What does the recycling number actually mean?
Sources
- ASTM International (2013). D7611 Standard Practice for Coding Plastic Manufactured Articles for Resin Identification. ASTM.
- Hussain KA, Romanova S, Okur I, et al. (2023). Assessing the release of microplastics and nanoplastics from plastic containers and reusable food pouches: implications for human health. Environmental Science & Technology.
- Marfella R, Prattichizzo F, Sardu C, et al. (2024). Microplastics and nanoplastics in atheromas and cardiovascular events. New England Journal of Medicine.
- IARC Working Group (2019). Styrene, Styrene-7,8-oxide, and Quinoline (IARC Monograph 121). International Agency for Research on Cancer.
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