New Questions About Common Chemicals

Environmental and health groups are pushing to restrict the use of phthalates - compounds used in cosmetics, toys and medical devices

By David Kohn
David Kohn is a freelance writer.

March 4, 2003

They have become ubiquitous: a group of little-known chemicals used in everything from nail polish to skin moisturizers to toys to shower curtains to time-release capsules to vinyl flooring. They soften plastic and dissolve fragrance into perfume. They are the new car smell in new cars.

But are they safe? Some researchers say there is evidence that the chemicals can cause birth defects and damage the male reproductive system. Several environmental and health groups are pushing to restrict the compounds' use in cosmetics, toys and medical devices.

The chemicals in question are a family of versatile substances known as phthalates, widely used for the past 50 years. U.S. manufacturers produce around a billion pounds a year.

"Rubber boots, swimming pool liners, traffic cones, insulation on electrical wiring - anything you see that's plastic, it's likely that it contains phthalates. They're everywhere," says Mike Shelby, director of the Center for the Evaluation of Risks to Human Reproduction at the National Institute of Environmental Health Services. The Center has spent the past 18 months studying phthalate risks.

Scientists have long known that relatively large doses of some phthalates (pronounced "tha-lates") can lead to health problems, including cancer. But researchers have begun to suspect that lower levels may also have negative effects. And new research suggests that humans are being exposed to higher levels of phthalates than previously realized.

"This is on everybody's radar now," says Boston University environmental epidemiologist Richard Clapp. "We may not have seen the fire yet, but there's an awful lot of smoke."

According to toxicologist Paul Foster of the National Institute of Environmental Health Sciences, researchers are finding that smaller doses than previously realized can cause harm. His recent work on how the chemicals affect the development of the rat reproductive system suggests that fetuses in the first trimester are particularly vulnerable.

The lowest level that produced adverse effects in the rats was 100 milligrams a day per kilogram of body weight. This is about 500 times more than what a 2001 study by the national Centers for Disease Control and Prevention found in the general human population. Many toxicologists prefer the level to be 1,000 times higher than a level that produces adverse effects. "When you're dealing with things that cause birth defects," Foster says, "you like to have a nice cushion." Foster also notes that he examined only one compound, dibutyl phthalate (DBP). Along with one other compound, Di 2-ethylhexyl phthalate (DEHP), DBP is considered to be the most toxic phthalate.

"I don't think anyone needs to panic," he says. "But I don't feel really comfortable with young women who are being exposed to two or three different phthalates."

Industry groups counter that phthalate-containing products pose no danger to humans. "Exposure in humans is well below levels that have shown no effects in animals," says Gerald McEwen, vice president for science at the Cosmetic, Toiletry, and Fragrance Association, based in Washington, D.C. "The data shows that these [levels of] chemicals are safe."

Most phthalate researchers say the jury is still out on phthalate risks - particularly their threat to developing fetuses and children.

Dozens of animal studies have shown that phthalates can disrupt the endocrine system, inhibiting male hormones and causing male infertility and birth defects. But animal studies alone do not provide enough proof, says Marian Stanley, manager of the American Chemistry Council's Phthalate Esters Panel, which presents the industry's side in the debate. "Nobody's been able to reliably link any harmful effects to humans," she says.

The reason, says Shelby of the Center for the Evaluation of Risks to Human Reproduction, is that research on humans barely exists. "Industry says there is no human evidence, and that's true," says Shelby. "But the absence of evidence doesn't mean there's no effect. In this case, it means that no one's studied it."

As concern over phthalates grows, more scientists are doing research on humans. A study published last year in Environmental Health Perspectives, the official journal of the National Institute of Environmental Health Sciences, found that a group of men with DNA-damaged sperm also had higher levels of diethyl phthalate (DEP) - regarded as one of the less toxic phthalates. "The data suggests there may be an association between phthalates and problems with semen. It's intriguing," says the study's leader, Professor Russ Hauser of the Harvard School of Public Health.

U.S. regulators have already restricted some phthalate use. Earlier this year, the Food and Drug Administration recommended that when performing procedures on male babies and boys, as well as women pregnant with boys, hospitals avoid using IV bags, blood bags and tubing made with DEHP. The compound, which makes the devices pliable, can leach from the plastic. The FDA also asked, but didn't require, manufacturers to label DEHP-containing medical devices so hospitals could more easily avoid them.

Much of the recent debate has focused on the chemicals' presence in cosmetics. A 2001 study by the CDC found widespread phthalate exposure, including higher than average levels of some phthalates in the urine of women of childbearing age. Some women exceeded the EPA's safety standard, a finding that scientists say are enough of a concern to warrant further study. A follow-up CDC study in January reported similar results.

The phthalates found in largest quantities were DBP and DEP , which tend to be used in cosmetics and perfumes. The EPA's "reference dose" - an estimate of the maximum daily exposure that is unlikely to cause adverse health effects - for DEP and DBP is 0.1 milligram per kilogram of body weight per day (a kilogram is 2.2 pounds). The agency, which set those levels over a decade ago, says it is now revising them.

Researchers surmised that the elevated levels of DBP and DEP could be caused by women's use of beauty care products.

"There's cause for concern," says researcher John Brock, who oversaw the CDC study. "We have broad exposure to phthalates in the population. We have animal studies that show risk. So we really need to know where these exposures are coming from."

In response to the finding of elevated levels in women of childbearing age, a coalition of three environmental groups decided last year to analyze phthalate levels in cosmetics. They tested 72 name-brand cosmetics - everything from shampoo to perfume to deodorant - and found phthalates in 52.

"We never found the word 'phthalate.' We read thousands of labels," says Charlotte Brody, director of Health Care Without Harm in Washington, D.C., one of the groups. Federal labeling laws do not require phthalates to appear on ingredient lists of many cosmetics and other products; they are usually part of the "fragrance," which is considered a trade secret, and so may be omitted from labels.

"Millions of women are being exposed to multiple phthalates," says Jane Houlihan, director of research at the Environmental Working Group, another coalition partner. "And they have no way of even knowing what products contain phthalates."

Pediatrician Lynn Goldman, for one, would like to know. Her 6-year-old daughter loves nail polish, and also bites her nails.

"I have no idea what is in those products," says Goldman, a professor of environmental health at Johns Hopkins University and former Environmental Protection Agency official who was in charge of regulating toxic chemicals during the Clinton administration.

Hair and nail salon workers "are breathing nail lacquers and hair sprays day in and day out," she said.

But the FDA says phthalate-containing beauty products are safe. In November, the Cosmetics Ingredient Review panel (CIR), an industry-funded safety panel that advises the FDA, reviewed existing scientific data and found that phthalates in cosmetics pose no risk. The FDA agreed.

"The consensus between the CIR and the FDA was that phthalates are safe in cosmetics," said FDA spokeswoman Veronica Castro.

Several cosmetics companies, including Aveda, have stopped using phthalates in new products. Recently, the European Union decided to phase out DEHP and DBP from use in cosmetics. The chemical industry argues that the move was not based on science, but on irrational fear and incomplete evidence.

Noting that some cosmetics are made without phthalates, Brody wonders why manufacturers don't simply replace the controversial compounds with other chemicals. McEwen says the answer comes down to logic: "Why should we change from something that is absolutely safe? That doesn't make sense."

Phthalate opponents say that even without ironclad proof that low levels cause harm in humans, there is enough data to warrant a ban. Animal studies must be considered, they say, particularly given the difficulty of doing phthalate studies in humans.

"It's very hard to study in people, and very hard to find problems even when they exist," says Goldman. "If a kid grows up and has fertility problems, are you going to know how much nail polish his mother used during pregnancy? We need to use the animal data."

The debate extends beyond cosmetics. Many soft plastic toys are made with diisononyl phthalate (DINP), which studies show causes liver damage in animals. Some environmental groups say the chemical, which makes up as much of 40 percent of some plastic playthings, can leach out at risky levels, particularly when kids suck on toys. Responding to a combination of research and pressure, some countries have restricted phthalates in toys. The EU has banned DINP in toys for kids 3 and under, while Japan has announced a plan to get rid of DEHP and DINP in toys for kids 6 and under. In 1998, U.S. toy manufacturers voluntarily agreed to stop using phthalates in pacifiers and rattlers. But environmental groups say many other toys still contain DINP.

Recently, the U.S. Consumer Product Safety Commission completed a four-year study, concluding that toys with DINP were not a health risk. While agreeing that DINP could be toxic, the commission said children sucked on toys an average of 1.9 minutes per day, and would have to suck for 39 minutes to ingest risky levels.

But environmental and consumer groups criticize the ruling. "The CPSC is erring on the side of exposing kids to a toxic chemical," said Andy Igrejas of the nonprofit, nonpartisan National Environmental Trust, which wants DINP banned from all 5-and-under playthings.

For some, the disputes over specific types of products miss the point. "It's wrong that we're asking about phthalates just in cosmetics or toys. People are getting phthalates from multiple sources," says Dr. Ted Schettler, science director for the Science and Environmental Health Network.

Some researchers believe that phthalates can migrate from packaging into food, especially fatty items like cheese and meat. An ongoing study by the Silent Spring Institute is looking at air and house dust in 120 Massachusetts houses and has found "significant concentrations" of phthalates, including DEHP and DBP. The study has been submitted for publication in a leading journal.

"That suggests we should consider inhalation as a pathway," says toxicologist Ruthann Rudel, who led the study.

One senior government researcher, who requested anonymity, said that because phthalates are part of so many products, no one has a clear picture of how and where humans are being exposed. He notes that the CDC study looked for only seven compounds; there are, he says, dozens used in commercial products.