Two new studies contain good news, bad news and worse news when it comes to the toxic chemicals in our bodies.

The good news, reported by the Centers for Disease Control, is that lead exposure in children is down significantly and secondhand-smoke exposure has been reduced.

The bad news, also from the CDC, is that Americans are carrying at least 148 toxic compounds in varying levels in their bodies, and little is known about what levels are a threat to health.

The most worrisome news, from the Environmental Working Group, shows that even in utero, babies have an average of 200 chemical contaminants in their bloodstreams. The EWG report analyzed 10 samples of umbilical-cord blood taken by the American Red Cross across the country.

The most prevalent chemicals in the newborns were mercury, fire retardants, pesticides and the Teflon chemical perfluorooctanoic acid (PFOA), recently characterized as a likely human carcinogen by the Environmental Protection Agency’s Science Advisory Board.

“If ever we had proof that our nation’s pollution laws aren’t working, it’s reading the list of industrial chemicals in the bodies of babies who have not yet lived outside the womb,” U.S. Rep. Louise Slaughter, D-N.Y., said of the EWG report in a press release.

Slaughter, who is leading the effort in Congress to hold chemical producers to higher standards, said she had similar tests done on her own blood, which was found to contain 271 harmful substances, including PCBs, flame retardant chemicals and PFOA.

In a response to the report from the American Chemistry Council, President Kenneth A. Cook wrote, “Scientists have long understood that our bodies can absorb substances - natural and manmade - present in our environment. … Scientists also know that detection of a chemical is not an indication of a risk to health and should not be raised as a cause for alarm.

“Researchers in this area echo CDC: ‘The measurement of an environmental chemical in a person’s blood or urine does not by itself mean that the chemical causes disease.’”

But the report also noted that separate studies are needed to determine what levels may cause disease or damage.

The CDC released its first National Report on Exposure to Environmental Chemicals in 2001 and has updated it every two years. The purpose is to find out what chemicals have gotten into Americans’ bodies and track the amounts over time.

For its latest findings, the CDC took blood and urine samples from about 2,400 people in 2001 and 2002 and tested for 148 environmental chemicals, including metals, pesticides, insect repellants and disinfectants.

Americans have lower levels of lead and secondhand-smoke byproducts in their bodies than they did a decade ago, according to the study, the most extensive of its kind. In the early 1990s, 4.4 percent of U.S. children ages 1 to 5 had elevated lead levels. That dropped to 1.6 percent between 1999 and 2002, according to the latest study.

The study also looked at 38 chemicals, mainly pesticides that were not measured during the last CDC analysis in 2003.

Kristin Schafer of the Pesticide Action Network, said the report is helpful but the chemicals the CDC tested for represent a “really small slice of all the chemicals we’re exposed to in the environment.”

For example, the CDC examined 43 pesticides, but the EPA registers more than 1,200, she said. The Environmental Working Group report, released July 14, focused on babies in utero. In that study, researchers at two laboratories found an average of 200 industrial chemicals and pollutants in umbilical cord blood from 10 babies born in August and September of 2004 in U.S. hospitals.

The umbilical cord blood, collected randomly by Red Cross, harbored pesticides, consumer product ingredients and wastes from burning coal, gasoline and garbage.

Such testing represents a whole new area of screening. In Virginia, there is no required testing for chemicals in newborns.

“We don’t routinely screen for any toxins like that,” said Wendy Rogers, a nurse in the intensive care nursery at Virginia Baptist Hospital.

She said the state requires metabolic screenings of newborns for seven disorders, including hypothyroidism and galactosemia, conditions that can lead to brain damage without treatment.

While Rogers wasn’t familiar with the CDC or EWG reports, she said she’s not surprised to learn that mothers can pass chemicals onto their babies in utero.

“We usually focus on drugs and alcohol,” she said, noting that such substances can affect the size and health of a newborn.

The EWG study represents the first reported cord blood tests for 261 of the targeted chemicals and the first reported detections in cord blood for 209 compounds. Among them are eight perfluorochemicals used as stain and oil repellants in fast food packaging, clothes and textiles, dozens of flame retardants and their toxic by-products, and numerous pesticides.

Of the 287 chemicals detected in umbilical cord blood, 180 cause cancer in humans or animals, 217 are toxic to the brain and nervous system, and 208 cause birth defects or abnormal development in animal tests, the report said.

The dangers of pre- or post-natal exposure to this mixture of carcinogens, developmental toxins and neurotoxins have never been studied. Chemical exposures in the womb or during infancy can be dramatically more harmful than exposures later in life. Children are more vulnerable because of rapid development and incomplete defense systems.

Laboratory costs for the cord blood analyses were $10,000 per sample.

U.S. industries manufacture and import approximately 75,000 chemicals, 3,000 of them at more than a million pounds per year. Health officials do not know how many of these chemicals pollute fetal blood and what the health consequences of in utero exposures may be, the EWG said.

“Decades-old bans on a handful of chemicals like PCBs, lead gas additives, DDT and other pesticides have led to significant declines in people’s blood levels of these pollutants,” the report said. “But good news like this is hard to find for other chemicals.”