Most plastic products have a number (the resin identification code) molded or imprinted on the container, usually on the bottom. This resin identification code is voluntary for plastic manufacturers but has now become standard to do on plastic products. Knowing this code means the consumer then becomes informed of the type of plastic and the health risks related to it. Below, the codes are described.
1. Polyethylene Terephalate (PET or PETE)
- Used in soft drinks, juice, water, beer, mouthwash, peanut butter, salad dressing, detergent, and cleaner containers. Leaches Antimony trioxide, causing respiratory and skin irritation among workers. Prolonged exposure linked to menstrual problems, miscarriage among female workers, and slower development in children's first twelve months of life. Antimony concentration increases the longer a liquid remains in such containers.
2. High-Density Polyethylene (HDPE)
- Used in opaque milk, water, and juice containers, bleach, detergent, and shampoo bottles, garbage bags, yogurt, and margarine tubs, cereal box liners. No known negative effects when used generally.
3. Polyvinyl Chloride (V or Vinyl or PVC)
- Used in toys, clear and non-food packaging (e.g., cling wrap), some squeeze bottles, shampoo bottles, cooking oil and peanut butter jars, detergent and window cleaner bottles, shower curtains, medical tubing, and many construction products (e.g. pipes, sliding). Described as one of the most hazardous consumer products ever created. Leaches di(2-ethylhexyl) phthalate (DEHP) or Butyl benzyl phthalate (BBzp), depending on which is used as the plasticizer or softener (usually DEHP). DEHP and BBzP are endocrine disruptors mimicking the female hormone estrogen; linked to asthma, allergic symptoms in children, certain cancers, and negative effects on various organs. Banned in Europe for use in plastic toys for children under three since 1999.
4. Low-Density Polyethylene (LDPE)
- Used in grocery store bags, dry cleaning bags, bread and frozen food bags, most plastic wraps, squeezable bottles (honey, mustard). No discovered negative effects associated with this type of plastic.
5. Polypropylene (PP)
- Used in tomato sauce bottles, yogurt and margarine tubs, medicine and syrup bottles, straws, Rubbermaid, and other opaque plastic containers, including baby bottles. No known health risks associated with general use, not heating or freezing.
6. Polystyrene (PS)
- Used in Styrofoam containers, egg cartons, disposable cups and bowls, take-out food containers, plastic cutlery, compact disc cases. Leaches styrene, an endocrine disrupter mimicking the female hormone estrogen, causing reproductive and developmental problems. Long-term exposure by workers shows various adverse effects on health.
7. Other
- A catch-all category including Polycarbonate, a dangerous plastic, and newer, safer, biodegradable bio-based plastics made from renewable resources such as corn, potato starch, and sugar cane. Polycarbonate is used in most plastic baby bottles, clear plastic “sippy cups”, Nalgene brand, and other “sports” water bottles, water storage containers, metal food can liners, some juice and tomato sauce containers, compact discs, cell phones, computers. Leaches Bisphenol A (BPA), linked to a wide array of possible adverse effects from low-level exposure: chromosome damage, decreased sperm production, early onset of puberty, behavioral changes, altered immune function, and sex reversal in frogs.
Important Note:
Two other types of plastic under code 7 are acrylonitrile styrene (AS) or styrene acrylonitrile (SAN), and acrylonitrile butadiene styrene (ABS). Both AS/SAN and ABS are higher quality plastics with increased strength, rigidity, toughness, and temperature and chemical resistance. Research into risks associated with AS/SAN and ABS is ongoing.
What does this mean for your plastic use?
Consider your and especially your children’s use of plastic numbered 1, 3, 6, and 7 (Polycarbonate), all which have been shown to leach dangerous chemicals. This does not mean the others are completely safe, that they have been studied less up to this point. So, if you have to use plastic, it is safest to stick to numbers 2, 4, 5, and 7 (other than Polycarbonate) whenever possible. If an item does not have a plastic code on it or if the type of plastic is unclear from the code (e.g., with #7, it’s likely it will not say it is Polycarbonate), your best bet is to contact the manufacturer and ask them what type of plastic was used to make the product.