Plastics, Plasticizers and Phthalates      

Sources of plastics
Plastics and IAQ
Plasticizers
Phthalates and the types of products in which they are used
Protection from hazards associated with plastics

Sources of Plastics

Plastics are everywhere in our society because of their many uses. For example, polyvinyl chloride (PVC) is a type of plastic that is very common in building materials. In the US in 1992 alone, 10 billion pounds of PVC resins were produced and 6.3 billion pounds were used in construction for things such as sewer pipes, flooring, siding, and weather-stripping. Plastics have made certain things very convenient and inexpensive. However, there are some drawbacks.

For one, plastics are made from fossil fuels, which are in limited supply. Many require the use of hazardous chemicals to make them. For example, the PVC industry is the largest single consumer of industrial chlorine worldwide. Using these hazardous chemicals can be dangerous for the workers who are making these plastics. In 1971, a rare cancer of the liver was traced to vinyl chloride exposure among workers who made PVC.¹

At the end of the product's useful life, there are also environmental concerns since plastics do not break down in hazardous waste dumps and many are difficult to recycle. When they are recycled, they cannot be recycled into what they were. For example, paper is recycled into paper and glass jars can be recycled into glass jars. However, the plastic that is recycled (4.7 percent in 1994) has new uses. For example, plastic bottles (polyethylene terephthalate [PET]) may find new life as drainage pipes, toys, carpet, filler for pillows or sleeping bags, and cassette casings.² Burning some plastics, like PVC, can release dangerous chemicals such as dioxin into the atmosphere.

Nevertheless, during a product's life, plastics have usually been considered safe. The main concerns are when the form of the plastics change?such as if they are heated. Otherwise, the main hazard, once the plastic items are manufactured, is the possibility of some off-gassing of volatile organic compounds (VOCs), because plastics are made from carbon-based materials.

Plastics and IAQ

A recent study in Finland has shown that indoor plastic materials may have adverse respiratory effects on children.³ Plastic materials are common in flooring and wall surfaces of bathrooms, kitchens, playrooms, and bedrooms. They are also common in day care centers and schools. Many of these materials, which are PVC based, can emit plasticizers, solvents, and alcohols. Odorous alcohols are often released if excessive moisture in the environment reacts with the plasticizers.

Children were studied for their frequency of asthma, allergic rhinitis, persistent wheezing, persistent cough, persistent phlegm, respiratory infections, and nasal congestion. Information was obtained on the chemical and microbiological air pollutants in their homes and day care, and the presence of plastic materials. The study, involving over 2,500 children, showed that the risks of respiratory symptoms typical of asthma were associated with the presence of plastics. The overall risks of asthma and pneumonia were also increased in those children exposed to plastics than those unexposed.

These studies confirmed earlier ones in Norway that showed an increased risk of bronchial obstruction during the first two years of a child's life if exposure to PVC and plastic surface materials occurred. The authors concluded that plastic materials emit chemicals that have adverse effects, and that these chemical levels vary based on the ventilation within the environment.

Plasticizers

One of the most recent concerns about plastics are plasticizers, the common additives to PVC. Plasticizers, which are also known as phthalates, make plastics flexible and durable. The nation's petrochemical companies produced about 1.5 billion pounds of phthalates in 1998.⁴ They are commonly used in the production of PVC to give flexibility for things like electrical cables, hoses, gaskets, and vinyl sheet flooring. There are concerns about phthalates since some behave like the hormones estrogen and androgen and could wreak havoc on the body's endocrine system. One researcher at Tufts University found that plastic containers in her lab caused estrogen-style changes in the cells she kept in them. Some of the health effects included decreased sperm counts, increased birth defects in male sex organs, and an increased chance of breast cancer.⁵ When chemicals mimic reproductive hormones like this, they are called endocrine disruptors. That is a common concern of many plastics. Recently a researcher at the University of Missouri found that extremely low amounts of Bisphenol-A (BPA is an essential ingredient of the plastics found in items such as in food containers, eyeglass lenses, nail polish and other everyday products) caused reproductive problems in mice. What was startling about this finding was that the amount used was an amount 100,000 times smaller than usually tested.⁶

Animal studies indicate that phthalates may also damage the liver, kidneys, and reproductive system. Because several phthalates are known to cause birth defects in animals and are emitted from a number of indoor sources, the Air Resources Board of the California Environmental Protection Agency had measurements taken in 125 homes in 1990. On the average, indoor concentrations of phthalates were about 2 to 15 times higher than outdoor concentrations.⁷

Phthalates and the Types of Products They are Used In⁸

• Di (2-ethylhexyl) phthalate [DEHP]: building products, food packaging, children's products and medical devices DEHP is added to PVC to make some soft, clingy wraps for commercial use. Consumer Reports tested 14 national and local brands of wrapped cheese for levels of plasticizers. The reason they chose cheese is that plasticizers are more likely to leach into fatty foods like cheese and hamburger. They found high levels of DEHP in the cheeses wrapped in deli cling wrap. People who eat several ounces of this cheese every day could get very high doses of DEHP that could possibly cause health problems. There were moderate levels of DEHP in some of the shrink-wrapped cheeses and in the waxed cheeses with plastic overwrap. There was little or no DEHP on individually wrapped slices of American cheese or blocks of cheddar in laminated foil wrap. Consumer Reports also tested plastic wrap. Of the seven national and store brands of plastic wrap they analyzed, only two contained any of the five plasticizers they were looking for. They reheated a cooked hamburger wrapped in those plastic wraps, but found just a little bit of the plasticizers had been absorbed where the patty was in contact with the wrap. In terms of the eight microwavable bowls from top manufacturers they examined, they found no plasticizers.⁹
  
  Some flexible vinyl plastic medical supplies, such as blood bags and intravenous (IV) tubing and IV bags, may contain DEHP that can leach out from the product into the patient.¹⁰ Medical device makers point out that the phthalates like DEHP leaching out of the plastic bags used to store blood actually help extend the blood's shelf life.⁴ In addition, some respiratory-care supplies are made from or packaged in DEHP-softened plastics. DEHP is also used in children's toys, wallcoverings, and a wide array of consumer products.
  
  In various laboratory studies on animals, DEHP has been "proven to cause a wide-range of toxic effects including damage to the kidneys, liver, reproductive systems, lungs, heart and developing fetus," said Health Care Without Harm (HCWH), an international coalition of medical and public health experts. Since DEHP is not chemically bonded to the vinyl product, small quantities may leach out. The Federal Drug Administration (FDA) currently limits the proportion of plasticizers like DEHP in food containers to 30 percent, but there are no such requirements for their use in medical supplies. HCWH also has commissioned its own research, conducted by the Lowell Center for Sustainable Production at the University of Massachusetts. They have reviewed all the scientific literature available on DEHP and found that the chemical does indeed leach out of medical products and expose patients?who may be particularly vulnerable to toxins?to unnecessary health risks. Those who are most exposed are also the most vulnerable since they are chronically ill people who spend a lot of time in hospitals.¹⁰
  
  This position was supported in August 2000 when the National Toxicology Program (NTP) of the US's National Institutes of Health (NIH) concluded that some phthalates have the potential to disrupt boys' reproductive development. They reached this conclusion after reviewing 1,000 studies and deliberating for 15 months. During this time they found that animal experiments have shown that low exposures during a critical time during the first trimester of a woman's pregnancy can grossly alter the organs in the developing male fetus that later produce and deliver sperm. The panel had the greatest concern about DEHP because of how toxic it is and because of how often it is used. The panel concluded that even normal exposure to this phthalate might be sufficient to threaten male reproductive organs developing in a healthy fetus, infant, or toddler. It expressed "serious concern" that critically ill babies might be harmed.¹¹
  
  People who just receive occasional IV medication are not at as much risk. The FDA has approved at least one line of PVC- and DEHP-free IV bags and corporations are developing a new generation of chlorine-free plastics, such as polypropylene and polyethylene. ¹⁰

• Diisononyl phthalate [DINP]: garden hoses, shoes, shoe soles, toys, and construction materials.

• Di-n-butyl phthalate [DBP]: cellulose plastics, solvents for dyes, food wrap, adhesives, perfumes, cosmetics, skin emollients, hairspray, nail polish, insect repellents In December 2000, the Environmental Working Group released a report warning women of childbearing age to avoid products containing DBP, which is a common ingredient in nail polish and other cosmetics. That is because this chemical may be responsible for an increase in birth defects in the sexual organs of boys. DBP has been used in a variety of consumer products since the 1930s and is found in about a third of all nail polishes, glosses, enamels, and hardeners in order to give the coating flexibility. It is also used in shampoos and sunscreens.¹² For more than 20 years, studies have shown that elevated levels of the DBP can cause birth defects in the male sex organs of laboratory animals, as well as low sperm counts and testicular atrophy. However, there was no published research on human exposure to DBP until September 2000, when the Centers for Disease Control and Prevention (CDC) released a study that found some level of the chemical in all 289 men and women tested. Levels of the chemical were especially high in women aged 20 to 45, which the CDC researchers said was probably due to their use of cosmetics.¹³
  
  In August 2000, after reviewing and deliberating for 15 months, the NTP concluded DBP could affect testosterone in fetal testes so that affected animals are born with a variety of malformations. ¹¹

• Diisodecyl phthalate [DIDP]: automobile undercoating, wires and cables, shoes, carpet backing, pool liners.

• Butyl benzyl phthalate: vinyl tile, food conveyor belts, artificial leather and traffic cones.

• Di-n-octyl phthalate [DOP]: flooring materials, carpet tile, canvas tarps, notebook covers DOP used to be utilized in the production of medical blood bags. It was one of the most common plasticizers in production with about 9 tons of DOP produced every year until 1987 when it was suspected of causing cancer. They stopped using it in blood bags when it was found to be leaching into the stored blood. ¹

• Di-n-hexyl phthalate: automobile parts, tool handles, dishwasher baskets, flooring, tarps, and flea collars.

Different kinds of plasticizers have been used for years in soft PVC toys such as rattles and teethers. However, there is some concern that young children may be ingesting small amounts of these chemicals when they chew or suck on these soft toys. Because of these concerns, the European Commission (EC) formally issued a ban on Dec. 1, 1999, on the sale of children's toys made of PVC containing phthalates. Though there is a lack of studies showing that this is a hazard in children's toys, the EC decision was based on what it called a "precautionary approach" to potential risks from children ingesting the chemicals while mouthing soft vinyl toys. The Consumer Product and Safety Commission's (CSPC) own study on the issue, released late in 1998, concluded that "few, if any children, were at risk" from the chemical, but they are continuing to study the issue. In the meantime, CPSC took the "precaution" in 1998 of asking U.S. toy companies to "voluntarily" stop manufacturing and selling toys containing phthalates for small children.¹⁴ Some major toy makers have begun phasing out the use of plasticizers used in their PVC toys. Though they say their products have always been safe, they responded to public demand to not have these chemicals in the toys that their children are putting in their mouths.¹⁵

Protection From Hazards Associated With Plastics

• Try to find natural substitutes for plastic products in your life. For example, instead of plastic shelves, use solid wood shelves. Instead of plastic bags for your groceries, use cloth bags.

• In the kitchen, use glass containers with lids or ceramic cookware. For your pet, use stainless steel or ceramic food bowls.

• Never microwave food in containers such as margarine tubs, cottage cheese cartons, or deli containers. When you microwave these lightweight, throwaway containers, they warp from contact with hot food and molecules of plasticizers and other chemicals are released and migrate into your food. Long-term exposure to low levels of these chemicals could be harmful to you since they were not meant to be consumed.¹⁶

• Though several plastic manufacturers have containers that are designed to go from the freezer to the microwave to the top rack of the dishwasher, remember these lightweight plastic products are reusable but aren't meant to be used forever.

• If you do heat up food in the microwave in a plastic container, make sure that the container is marked that it is microwave-safe.

• Do not reuse plastic trays or containers from frozen dinners or entrees.

• Do not microwave or defrost foods in their packaging materials.

• Do not let plastic wrap touch food when it is cooked in a microwave.

• Buy meat from a butcher and have it wrapped in paper.

• Buy cheese from a wheel and wrap in paper before placing in a plastic bag.

• Use plastic wraps made of polyethylene rather than PVC, because polyethylene products do not contain plasticizers.

• Avoid plastics with the #3 recycling code that indicates PVC; #1 and #2 plastics are safer since they are chlorine-free.

• If you buy cheese or any other fatty food wrapped in cling wrap, cut off the outer layer in case plasticizers leached into the food.

• A safer substitute for PVC piping would be vitrified clay pipe. There are vitrified clay pipes in use today that are over 170 years old and still in perfectly good shape. The expected service life is commonly given as 100-plus years, more than twice that of pipe made from any other material, and several manufacturers offer 100-year warranties. This pipe is smooth and very resistant to chemicals. The downsides are that it is heavy, is expensive to install, and may be hard to find.

• In an attempt to find safer types of plastics, a plastic derived from corn and wheat has been introduced. The manufacturers hope that it can someday be used to make carpet fibers, packaging, clothing and other products.¹⁷

References

1. Malin N, Wilson A. Should we phase out PVC? Environmental Builder's News. 1994 Jan/Feb.;3(1).

2. U.S. Environmental Protection Agency. Plastic Facts: www.epa.gov/grtlakes/seahome/housewaste/src/plastic.htm.

3. Jaakkola, et al. Am J. Public Health. 2000 May;Vol 90:797-799.

4. Ivanovich D. Sizing up plasticizers; hazard possibility debated. The Houston Chronicle. August 20, 1999; Business page 1.

5. Lawrence. Chemicals may cling, too; plastics possible source of kitchen health hazard. The Boston Herald. January 25, 1999; page 3.

6. Ingredient in household plastics shows reproductive abnormalities in mice. The E-Newsletter of the National Clearinghouse for Worker Safety and Training. December 29, 2000: www.wetp.org/newsbriefs/dec00/nb29dec00.htm.

7. Holmes JR. Indoor air concentrations of phthalates and PAHs in Southern California homes. Brief Reports to the Scientific and Technical Community, No. 94-10, California Environmental Protection Agency Air Resources Board. 1994: www.arb.ca.gov/research/resnotes/notes/94-10.htm.

8. Phthalates and their uses. The Seattle Times. August 26, 2000: http://seattletimes.nwsource.com/news/nation-world/html98/alts1chem26_20000826.html.

9. Hormone mimics hit home. Consumer Reports. June 1998;63(6):52.

10. Knight D. Safety of plastic medical devices questioned. Inter Press Service. July 5, 1999.

11. Raloff J. New concerns about phthalates: ingredients of common plastics; may harm boys as they develop. Science News. 2000;158(10):152.

12. Lowy J. Nail polish ingredient linked to birth defects in boys. Pittsburgh Post-Gazette. December 5, 2000: page F1.

13. Kohn MC, Parham F, Masten SA, Portier CJ, Shelby MD, Brock JW, and Needham LL. Human exposure estimates for phthalates. Environ Health Perspect. 2000;108(10):A440-A442.

14. Dawson C. Chairman Brown boasts of regulatory success in National Press Club speech. CPSC Monitor. 2000;5(1): www.consumeralert.org/pubs/monitor/2000/Jan00.htm.

15. Warren S. Toy makers say bye-bye to plasticizers. Wall Street Journal. November 12, 1998; Section B, page 1.

16. Steiner A, Williamson C. Check packaging to ensure that it's safe to reheat. The Houston Chronicle. February 3, 1999; Food page 7.

17. O'Connor M. Corn-based plastic invented. Architecture. March 2000; p 41.