There are tens of thousands of chemicals in everyday products, but only a fraction of these have been tested for toxicity and health effects in the United States

Perchloroethylene, also known as PERC, is one of more than 62,000 industrial chemicals that were presumed safe in 1976 when the federal government began regulating chemical compounds. Most have never been investigated for their health effects. Some of these chemicals are found in basic household products, and even measured in parts per billion they can have far reaching health effects.

Three recent studies address the link between early-life chemical exposure and long-term health concerns. Richard Denison, with the Environmental Defense Fund advocacy group, said these studies offer new insights into a field many have been hesitant to investigate.

"Most of the data we've relied on in the past has been data derived from laboratory animal studies,” Denison said. “But increasingly the field of epidemiology is finding that linkages directly to people can be established between chemical exposures and certain types of health effects."

The first study, carried out by researchers at Boston University analyzed the impact early-life exposure to PERC has on people engaging in “risky behaviors” such as smoking, drug use, or alcohol abuse.

"What they found was a much higher incidence, some 50 to 60 percent of an increase in the extent of these risky behaviors was observed in the individuals who had been exposed early in life to this solvent compared to those who had not,” Denison said.

In a second study, researchers in New York tracked the connection between phthalates and childhood obesity. Phthalates are a family of chemicals found in a range of everyday products including perfume, cosmetics, flooring, plastics, and medical devices.

The correlation between phthalate exposure and obesity was found to be very strong.

“Diet and lifestyle, exercise levels, all affect this (study),” Denison said. “What, increasingly, the science is pointing to, however, is that early life exposures to certain chemicals can predispose people to being obese later in life. These are chemicals that we know are similar to hormones that are naturally present in the body and they can interfere with the effects of those hormones even at very low doses."

A third study analyzed the relationship between exposure to perfluorinated chemicals and levels of antibodies in children. Perfluorinated chemicals, known as PFCs, contain fluorine, a substance that repels grease. Perfluorinated chemicals are commonly found in Teflon and other products with stick-resistant coatings.

“This study looked in particular at a group of these chemicals in a very large group of kids that were immunized early in life for diphtheria and other diseases,” Denison said. “And what they found was that the higher the levels of these chemicals in the bodies of these kids, ages five to seven years old, the lower the levels of antibodies to these two vaccines.”

Across these recent studies, one trend is clear.

“When we are exposed to things early in our lives, they have some profound effects on our immune system, our mental capacity, our ability to regulate our weight,” Denison said. “These kinds of fundamental processes in the human body seem to be being affected by early life exposures.”

On its website, Teflon manufacturer DuPont says Teflon is safe to use.

“Over the past 40 years, there have been only a few reported accounts of polymer fume fever, a minor health effect with reversible flu-like symptoms, as a result of severely overheating nonstick cookware,” DuPont says.

But DuPont stopped using Perfluorinated chemicals in their nonstick coatings.

Denison argues that the Toxic Substances Control Act of 1976, the law that regulates chemicals in everyday products, is obsolete.

At a 2009 U.S. House of Representatives hearing on revising the TSCA, Denison said the TSCA does not hold chemical manufacturers accountable for the safety of their products.

“When (TSCA) grandfathered in the tens of thousands of chemicals that were on the market at the time it was passed and which still today constitute the vast majority of chemicals in use, TSCA granted each of them a strong 'presumption of innocence' by not requiring them to be tested or shown to be safe. Under TSCA, the EPA and, consequently, the public shoulders the burden of proof,” Denison said.

Resources such as the Cosmetics Database can help individuals track the known chemicals in beauty products, however, many chemical ingredients are kept secret by manufacturers.

“We really need a national solution that makes sure that these chemicals are fully tested before they get into the marketplace so that people, don't have to worry about themselves and their families,” said Denison.

Denison’s summaries of the studies as well as links to the original research can be found on his blog.

In April 2011, Senator Frank Lautenberg introduced the "Safe Chemicals Act of 2011" (S. 847).