Hmmm.. probably none of them.
Ok, ok, that’s not the answer you were looking for. Here is a break-down of plastic types by recycling number. Sometimes the number is revealed in a triangular recycle symbol at the base of a product. Other times, manufacturers do not disclose the plastic type. Find out, or do not use!
My rule of thumb is only plastic types 2, 4 or 5 for food storage, and switch to glass or stainless whenever possible!
1 Polyethylene terephthalate (PET or PETE)
Used to make soft drink, water, sports drink, ketchup, and salad dressing bottles, and peanut butter, pickle, jelly and jam jars.
GOOD: Not known to leach any chemicals that are suspected of causing cancer or disrupting hormones. Only designed to be used once. Do NOT wash and reuse.
2 High density polyethylene (HDPE)
Milk, water, and juice bottles, yogurt and margarine tubs, cereal box liners, and grocery, trash, and retail bags.
GOOD: Not known to leach any chemicals that are suspected of causing cancer or disrupting hormones.
3 Polyvinyl chloride (V or PVC)
Most cling-wrapped meats, cheeses, and other foods sold in delicatessens and groceries are wrapped in PVC. PVC is also vinyl, which pops up EVERYWHERE once you start keeping an eye out for it.
BAD: To soften into its flexible form, manufacturers add “plasticizers” during production. Traces of these chemicals can leach out of PVC when in contact with foods. According to the National Institutes of Health, di-2-ethylhexyl phthalate (DEHP), commonly found in PVC, is a suspected human carcinogen. PVC also off-gasses, releasing toxic fumes into the air (think new shower curtain smell).
4 Low-density polyethylene (LDPE)
Some bread and frozen food bags and squeezable bottles.
OK: Not known to leach any chemicals that are suspected of causing cancer or disrupting hormones, but not as widely recycled as #1 or #2.
5 Polypropylene (PP)
Some ketchup bottles and yogurt and margarine tubs.
OK: Hazardous during production, but not known to leach any chemicals that are suspected of causing cancer or disrupting hormones. Not as widely recycled as #1 and #2.
6 Polystyrene (PS)
Foam insulation and also for hard applications (e.g. cups, some toys)
BAD: Benzene (material used in production) is a known human carcinogen. Butadiene and styrene (the basic building block of the plastic) are suspected carcinogens. Energy intensive and poor recycling.
7 Other (usually polycarbonate)
Baby bottles, microwave ovenware, eating utensils, plastic coating for metal cans
BAD: Made with biphenyl-A, a chemical invented in the 1930s in search for synthetic estrogens. A hormone disruptor. Simulates the action of estrogen when tested in human breast cancer studies. Can leach into food as product ages.
Adapted from Green Remodeling, by David Johnston and Kim Master (New Society Publishers, 2004).