Tiny red flecks — rayon fibers — will soon identify the only BPA-free thermal-printed store receipts in North America. Credit: Appleton

Appleton Paper, a company in Wisconsin, makes the kind of paper used for sales receipts. Starting in the first two weeks of November, the company’s receipt paper comes with something new — tiny flakes of red fibers on the back. Next time you come across a receipt, flip it over and see whether you can see red.

If you do, rest easy — because Appleton’s receipts do not contain bisphenol A (BPA), a chemical that has been in the news. Recent studies show BPA could be hazardous to your health. BPA is called a hormone disruptor, which means it enters the body and acts like a hormone, a chemical that can control body processes. When BPA acts like hormones, the body’s real hormones may have trouble doing their job.

Studies have turned up a link between BPA and heart disease, and exposure to the chemical might make a person more likely to develop diseases such as diabetes. In roundworms, which are often used in the laboratory as a model for humans, BPA interferes with reproduction. That could mean bad news for human reproduction, too.

In three separate studies last year, conducted all over the world, researchers discovered BPA in cash register and ATM receipts. Worse yet, further studies showed that the BPA rubs off easily onto a person’s hand. A recent report from the French government says this BPA is quickly absorbed into the skin and then the bloodstream.

“I won’t touch receipts now,” Frederick vom Saal told Science News. He is a scientist at the University of Missouri in Columbia who investigated receipts as part of a study by the nonprofit Environmental Working Group. He is now working on a study that looks not only at how BPA travels from receipt to skin, but also at how much of that BPA later turns up in a person’s urine or blood.

A recent study of pregnant American women found that cashiers, who work with receipts all day, have higher levels of BPA in their blood and urine. Since BPA passes so easily into the body, it may also pass easily into the fetus, which means a mother’s BPA exposure could be hazardous to her children.

Receipts are not the only source of BPA — far from it. BPA is used in the production of plastic. Plastic is everywhere, which means BPA is all around us. The BPA travels from the plastic into the body when the plastic is heated — in a dishwasher or microwave, for example — or when it is scratched.

In addition to water bottles and other containers, plastic shows up in places you wouldn’t expect: bike helmets, telephones, computers. As a quick example, consider a typical automobile: plastic is used in the seats, dashboard, parts of the body and some engine parts.

BPA is in receipts and in plastic, and a recent study turned up BPA in yet another alarming source: food. In a recent study, scientists in Texas tested 31 types of canned foods or foods packaged in plastic. They discovered measurable amounts of BPA in 60 percent of the food products.

The Environmental Protection Agency recommends people consume no more than 50 micrograms of BPA per kilogram (2.2 pounds) of body weight. The food-based BPA measured by the Texas scientists is far below that guideline.

Scientists are still trying to determine both the real risks of BPA, and how much of the chemical is too much. To be on the safe side, check your receipts — and your plastic.

POWER WORDS (from the Yahoo! Kids Dictionary and the National Institutes of Health)

plasticizer Any of various substances added to plastics or other materials to make or keep them soft or pliable.

plastic Any of various organic compounds produced by polymerization, and capable of being molded, extruded, cast into various shapes and films, or drawn into filaments used as textile fibers.

BPA A chemical produced in large quantities for use primarily in the production of plastics.

hormone A substance produced by one tissue that travels through the bloodstream to another tissue to effect physiological activity, such as growth or metabolism.

Scientists and regulators are looking into the safety of two chemicals found in many plastic products — including some kinds of baby bottles. Credit: iStockphoto

Try to count everything you use that’s made of plastic. I dare you.

Done yet? I didn’t think so.

Your list may include toys, yogurt containers and pens. But did you remember to include telephones, bike helmets, spatulas and shower curtains? How about straws, food wrappers, picture frames and the seat covers on your school bus?

Plastic is everywhere because plastic is an extremely useful material. It is cheap, strong and lightweight. What’s more, it can take on nearly any form or shape, from soft and stretchy to hard and glasslike.

Plastic, however, is far from perfect. It may even be bad for us, according to a growing body of research. Studies now suggest that toxic chemicals can get out of some types of plastic, get into our bodies, and cause a variety of health problems, including cancer, birth defects and attention deficit hyperactivity disorder (ADHD).

Fetuses and young children seem to be at greatest risk. And since babies tend to put plastic things (and everything else) in their mouths, many parents are worried.

Two types of chemicals in particular have raised special concern lately. They are called phthalates (pronounced thal’ ātz) and bisphenol (biz fē’ nawl) A, BPA for short. Not all plastic products contain them. But the ones that do are surrounded by controversy. That’s because experts disagree about how dangerous these chemicals are.

If you follow the news in coming months, you’ll notice more and more stories about phthalates and BPA. And as the research builds, it’s up to you to decide how plastic will fit into your life. So, what do you need to know to make smart choices about plastic?

From Bottle to Body

Plastic is a single word, but plastic isn’t just one thing. Think about how different a food wrapper is from a water bottle. What all plastics share in common are plasticizers — special chemicals that allow the material to be molded into nearly any shape or texture. Plasticizers are added to plastic during the manufacturing process.

Phthalates and BPA are two types of plasticizers that work in different ways. Phthalates add softness and squishiness to things like shampoo bottles, raincoats and rubber duckies. These molecules are also used in perfumes and makeup. BPA, on the other hand, gives a hard, clear, almost glasslike feel to products such as baby bottles, blender bowls and reusable, see-through Nalgene-brand water bottles (milky-colored, soft Nalgene bottles don’t contain BPA). BPA also appears in the lining of many food and soda cans, in DVDs and in other unexpected places.

Widespread use of BPA and phthalates worries many scientists because both chemicals belong to a group called hormone disruptors. In the body they act like hormones. Hormones, such as estrogen and testosterone, are two of the body’s important messenger molecules. They can tell cells when to turn on or off the cells’ genetic material. That’s how hormones direct the complicated development of a fetus from just a few cells into an actual baby with arms, legs, ears and organs. They also control growth in all of us. They even control the changes at puberty that get our bodies ready to become adults.

When some other chemical imitates a hormone, though, our actual hormones can’t do what they need to do. That can cause all sorts of problems. In hundreds of experiments, animals exposed to hormone disruptors in the womb went on to develop breast cancer, early puberty, diabetes, obesity, behavioral problems and other health issues.

“What we know is that BPA and phthalates disrupt hormones, and that hormones are necessary for normal human development, brain development and reproductive development,” says David Wallinga, director of the Institute for Agriculture and Food Policy’s Food and Health Program in Minneapolis.

Especially worrisome, Wallinga says, is that just tiny doses of a hormone disruptor can have a big impact. That’s because hormones work at extremely low levels in the body, so it doesn’t take much to get in their way.

Most of us already have tiny amounts of hormone disruptors in our bodies. A recent study by the U. S. Centers for Disease Control and Prevention found traces of BPA in 93 percent of the more than 2,500 people tested in the United States.

How do these chemicals get into us? When plastic is heated in the microwave or dishwasher, chewed on or scratched, the chemicals can seep out of the plastic. Even though we can’t see these molecules, we eat them, drink them and breathe them in.

Scientists and parents are especially worried about young children, who tend to chew on everything, including plastic. BPA is a common ingredient in baby bottles, teething rings, sippy cups, baby-formula cans and other products specifically designed to go into the mouths of little kids. Kids are a cause of concern both because they are likely to be exposed to plastics more than adults and because their bodies are more sensitive to the risky chemicals. Hormones play a particularly important role in the developing bodies of both babies and fetuses.

The Debate Goes On

Despite the growing sense of worry, debates about what to do continue between those concerned about the chemicals, the plastics industry and the government agencies charged with deciding on what’s safe and what’s not. That’s because there’s still no proof that BPA and phthalates are making people sick. So far, most experiments have involved animals and cells growing in test tubes.

Bisphenol A, a chemical linked to health problems, can seep out of hard, clear plastic water bottles, like the one shown above. Metal and glass bottles may be a safer way to store drinking water! Credit: T. Siegfried

In humans, the strongest evidence of harm comes from associations: People who have been exposed unintentionally to BPA and phthalates seem to develop the same types of health problems as animals that are deliberately exposed. In science, though, you need to show that one event directly causes another. It’s not enough to just observe that chemical exposure and diseases happen to the same people: The two might just be a coincidence.

Yet, direct proof in humans may never come, Wallinga says. For ethical reasons, researchers can’t expose pregnant women to risky chemicals, then wait to see what happens.

Scientists have also had trouble repeating some of the studies that make these plasticizers look bad, says Steven Hentges, a chemist from the American Chemistry Council, a plastics-industry group in Arlington, Virginia. The group sponsors a number of websites, which compile news reports and studies showing that plasticizers are safe.

“Consumers would have to eat more than 500 pounds of food and beverages in contact with [BPA-containing plastic] every day of their lives to exceed exposure levels determined to be safe,” reads a fact sheet on one such site, called factsonplastic.org.

But one new study that was reported online in the Sept. 13 Science News, found that in human body fat, BPA suppresses a real hormone that normally protects people from heart attacks and type 2 diabetes. The amount of BPA that it took to do this was the same as what is found in most people’s blood. These values were well below values that the government has declared are safe.

That story also reported on a Spanish study that showed BPA — in amounts typical of what’s already found in people — can alter the body’s production of insulin, a hormone that breaks down sugars. This study was conducted in mice, not people. But its findings suggest BPA might help encourage the body’s development of diabetes, a life-threatening hormonal disease where the body can’t use sugar appropriately.

A story in the Oct. 11 Science News actually links BPA concentrations in people to heart disease, changes in liver function and type 2 diabetes.

After evaluating some data — but not all of these studies — many large governmental agencies have concluded that there still is nothing to worry about. In July, Europe’s food safety organization issued a statement saying that BPA-containing products are fine for everyone, including kids. In August, a draft (not final) report by the U.S. Food and Drug Administration came to similar conclusions.

But several large groups of well-known scientists have expressed concern about hormone disruptors in plastics. And some states and countries are taking action.

New Rules, New Products

Dozens of countries, including the European Union, Japan, Canada and Mexico have already banned phthalates from products made for children younger than 3. California and Washington State have done the same. And a number of other states are considering similar rules.

As for BPA, Canada became the first country to ban the chemical from baby bottles in April. A dozen states are considering it.

Even in places where it is legal to sell baby products that contain these chemicals, many major stores are stocking their shelves with versions that don’t contain them. Toys“R”Us and Wal-Mart are two examples. At the same time, more and more manufacturers are making BPA-free and phthalate-free versions of their products.

If you want to know what’s in the plastics you eat and drink out of, look for the small number that’s usually etched into the bottom of the product. In food and drink containers, the numbers 1, 2, 4, and 5 are free of BPA and phthalates. But avoid microwaving even these plastics —or reusing them.(To learn more about safety and plastics, visit healthylegacy.org.

If you’re concerned, wood, glass and cloth make good alternatives to plastic. Or you can buy plastic toys made in countries that have bans on certain plasticizers.

“I have two rubber duckies sitting on my desk,” says Lindsay Dahl, project coordinator at Healthy Legacy, an advocacy group that opposes toxic chemicals in everyday products. “One has phthalates. One doesn’t. The one that does is sold in the United States. The one that doesn’t is sold in Europe.”

When in doubt, call the company to ask about what’s in their plastics. While you’re on the phone, tell them what you think about the issue. They might be interested to know that kids are keeping an eye on them.

Teacher’s Question Sheet: Our Plastic World

SCIENCE

Before reading:

1. What do you own that’s made out of plastic?

2. Why do you think those items were not made out of some other substance — such as wood, glass, or metal?

3. What do you think the advantages are of something being made out of plastic?

During reading:

1. What is plastic? Why might some types pose a health concern?

2. What is a plasticizer? How does it work?

3. What are hormones and how can a building block of plastics resemble a hormone?

4. How strong is the evidence that ingredients of plastics might affect health?

5. Are all members of the population at similar risk from plastics’ ingredients? Why or why not?

After Reading

1. Now that you know there are potential risks from using plastics — but that the human risks have not been proven yet — how important do you think it would be to avoid using plastic items?

2. For which plastic items in your home or school do you think there might be good substitutes? For which can you think of no substitutes?

3. Plastic baby bottles have been considered a potentially big concern. Moms used to use glass bottles. What are at least three reasons why modern moms might prefer plastic?

4. The author says these junk pieces travel at breakneck speed. Do you think that would make them more or less of a danger to astronauts in orbit?

5. If you think plastic items may pose a health risk, what should we do with all of those that are in our homes? How would you discard them? What might be the best way to ensure that plastic trash doesn’t become a hazard in the trash?

6. Do you think plastic trash in lakes and streams would pose a risk to fish and other aquatic life? Why or why not?

SOCIAL STUDIES

1. How has the widespread availability of plastics in the last 50 years changed society? To figure out, imagine a world where all of today’s plastics were instead made of wood, rubber, metal, stone or glass.

2. What features of plastic make them better than wood, rubber, metal, stone or glass? Hint: Compare the cost, weight and flexibility of plastic items against similar materials made from wood, rubber, metal, stone or glass.

3. If plastics were totally nontoxic, that is posed no health risk, what aspects of plastic items might make less desirable than similar items made from other materials?

LANGUAGE ARTS

1. Write a short essay on why plastic baby bottles are better or worse for today’s infants. Imagine having to explain to your mom or a neighbor — someone who knows nothing about the science plastics — why concerns have been raised about the safety of plastics. Explain why you think this mom should or should not be concerned about these new studies.

2. Imagine a world in which all plastics were banned. Describe in a 10 sentences or less how this would change your environment? Hint: Consider what things in your bedroom, your game room, your kitchen and your yard might be different.

3. Hold a classroom debate on the value of keeping plastics. Let one group argue persuasively that any benefits they pose would outweigh their risks. Let the other group argue that their potential risks outweigh the benefits.