Frequently Asked Questions about Plastics

These FAQs describe the potential hazards associated with plastic containers, mostly through microwaving or reuse. You will also learn about the recycling process and how to identify the different types of plastics.

• What do the numbers and triangles mean on the bottom of plastic containers?
• Are all plastics safe?
• Should I be concerned about using plastic in the microwave?
• Will a plastic bottle leach harmful substances into my water if I reuse it?
• What can I do to reduce my exposure to the chemicals in plastic?
• What happens to the products that I take to my local recycling center or place on the curb for pickup?

What do the numbers and triangles mean on the bottom of plastic containers?

The numbers with the triangles surrounding them describe the type of plastic material, or resin, used to make the container. If you are asked to sort your plastic materials, use these numbers to determine if products are made out of plastics that your recycling center or curbside pick-up will collect. Generally, #1 (PETE) and #2 (HDPE) plastics are most often collected and recycled.

1. PETE or PET (polyethylene terephthalate): used for most clear beverage bottles.
2. HDPE (high density polyethylene): used for "cloudy" milk and water jugs, opaque food bottles.
3. PVC or V (polyvinyl chloride): used in some cling wraps (especially commercial brands), some "soft" bottles.
4. LDPE (low density polyethylene): used in food storage bags and some "soft" bottles.
5. PP (polypropylene): used in rigid containers, including some baby bottles, and some cups and bowls.
6. PS (polystyrene): used in foam "clam-shell"-type containers, meat and bakery trays, and in its rigid form, clear take-out containers, some plastic cutlery and cups.
7. Other (usually polycarbonate): used in 5-gallon water bottles, some baby bottles, some metal can linings.

Are all plastics safe?

No.
You should avoid buying and using #3, #6, and #7.

#3 PVC (polyvinyl chloride, or vinyl):

PVC is hazardous in all of its phases: manufacturing, the products themselves in the home, and in the disposal of it.

One of the most toxic plastics, PVC is often used to make food packaging and in the production of plumbing and construction materials. PVC is commonly used in teethers and soft squeeze toys for young children, beach balls, bath toys (some rubber duckies), and dolls. Check the product or label to see what number plastic has been used.

To soften PVC into these flexible forms, various toxic chemicals are added as "plasticizers." Traces of these chemicals, known as adipates and phthalates, can leak out of PVC into your food. Some phthalates have been linked to cancer, kidney and liver damage, harm to developing reproductive organs, and premature breast development in baby girls. Inhaling these chemicals can also worsen asthma in children.

Because it contains a variety of additives and lacks a uniform composition, PVC is far less recyclable than other plastics.

Learn more about what makes up PVC: vinyl chloride.

Click here to learn about the alternatives to PVC that are available.

#6 PS (polystyrene):

#6 plastic may leach styrene into the food it touches. A recent study in Environmental Health Perspectives concluded that some styrene compounds leaching from food containers are estrogenic (meaning they can disrupt normal hormonal functioning).

Styrene is also considered a possible human carcinogen by the World Health Organization's International Agency for Research on Cancer.

#7 Other, most commonly PC (polycarbonate):

#7 polycarbonate may be able to release its primary building block, bisphenol A, another suspected hormone disruptor, into liquids and foods. Although several governments in Europe and North America currently hold polycarbonate tableware and food storage containers to be safe, this is a highly active area of research. Additionally, while category 7 most often refers to polycarbonate, it is actually a catchall "other" category, and it may not be possible to be sure just what it is. The Center for Environmental Oncology recommends avoiding these containers wherever possible.

Click here to view and print the Center for Environmental Oncology of UPCI's plastics card, a pocket guide for remembering which types of plastic to avoid buying or using.

Should I be concerned about using plastic in the microwave?

Whether substances found in plastic can leach out into food or into the air of our homes is an active area of research. The Center for Environmental Oncology of UPCI contends that no plastics (including Styrofoam, wraps or containers) should be used in the microwave. Studies are looking at chemicals called "plasticizers." Plasticizers are used in some plastics and other products. They help make the plastic more flexible, but they do not become part of the plastic. Under the right conditions, plasticizers may leach out of the plastic.

Plasticizers can be environmental estrogens, called endocrine disruptors

The plasticizers called nonylphenol and bisphenol A are both weak environmental estrogens.

• Bisphenol A is used in:
  • the lining of some tin cans
  • dental sealants
  • baby bottles and pacifiers
• Nonylphenol is used in many applications, including:
  • some laundry detergents
  • some paints
  • cosmetics
  • as a non-pesticide ingredient in many commercial pesticide formulations.

Some organizations, such as the USDA, state that you should only use cookware that is specially manufactured for use in the microwave oven. Glass, ceramic containers, and all plastics should be labeled for microwave oven use. Never let plastic wrap touch your food during microwaving, however. The Center for Environmental Oncology still suggests that no plastics be used in the microwave, especially plastic storage containers such as margarine tubs, take-out containers, whipped topping bowls, and other one-time use containers. These containers can warp or melt, possibly causing harmful chemicals to migrate into the food. Click here for more information.

Will a plastic bottle leach harmful substances into my water if I reuse it?

Most convenience-size beverage bottles sold in the U.S. are made from polyethylene terephthalate (#1 PET). The FDA has determined that PET meets standards for food-contact materials established by federal regulations and therefore permits the use of PET in food and beverage packaging for both single use and repeated use. The FDA has evaluated test data that simulate long-term storage and that support repeated use.

The toxicological properties of PET and any compounds that might migrate under test conditions have also been well studied. The results of these tests demonstrate that PET is safe for its intended uses.

The Center for Environmental Oncology of UPCI, however, still recommends that beverage bottles not be reused more than a few times because of the risk that toxic materials might leach into your food.

What can I do to reduce my exposure to the chemicals in plastic?

• Choose packaging that's made from truly recyclable materials: paper, glass, metal cans.
• Bring your own container to salad bars, yogurt shops, etc. - any place you'll be served in plastic.
• Buy in bulk, whenever possible. It's the least-packaged option.
• For wrapped foods, choose butcher paper, waxed paper or cellulose bags.
• Bring cloth bags to your supermarket to carry groceries home.
• Choose #1 (PETE) or #2 (HDPE) whenever plastic cannot be avoided! These are the most commonly recycled plastics.
• Some plastics are not readily recyclable, such as #3 (PVC), #6 (PS), #7 (often polycarbonate). Check to see which ones are recycled by your community.
• For more ways to reduce your plastic usage and exposure to chemicals in plastic, click here.

What happens to the products that I take to my local recycling center or place on the curb for pickup?

Recyclables are sent to a materials recovery facility to be sorted and prepared into marketable commodities for manufacturing. Processors purchase the materials and will then bale or shred them. After this process is complete, the pieces are sold to manufacturers who turn the raw materials into new products.

Glass and aluminum are often remanufactured into "new" glass bottles and aluminum cans, but plastic bottles typically cannot be remanufactured into plastic beverage bottles. Currently, the U.S. Food and Drug Administration (FDA) does not allow plastic beverage bottles to be recycled into "new" ones because of the possibility that the material will retain harmful chemicals, such as bleach and soap, contacted during processing. Instead, these recyclables are made into items such as laundry detergent bottles, carpets, clothes, sleeping bags, and other items that do not come in direct contact with food.

Click here to visit our recycling page.

To inquire about Center for Environmental Oncology activities, please send an e-mail to envonc@upmc.edu or call 412-623-3375.