Unborn U.S. babies are soaking in a stew of chemicals, including mercury, gasoline byproducts and pesticides, according to a report released.

Although the effects on the babies are not clear, the survey prompted several members of Congress to press for legislation that would strengthen controls on chemicals in the environment.

The report by the Environmental Working Group is based on tests of 10 samples of umbilical-cord blood taken by the American Red Cross. They found an average of 287 contaminants in the blood, including mercury, fire retardants, pesticides and the Teflon chemical PFOA.

"These 10 newborn babies ... were born polluted," said New York Rep. Louise Slaughter, who spoke a news conference about the findings on Thursday.

"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," Slaughter, a Democrat, said.

Cord blood reflects what the mother passes to the baby through the placenta.

"Of the 287 chemicals we detected in umbilical-cord blood, we know that 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.

Blood tests did not show how the chemicals got into the mothers' bodies, or what their effects might be on the babies.

MERCURY AND PESTICIDES

Among the chemicals found in the cord blood were methylmercury, produced by coal-fired power plants and certain industrial processes. People can breathe it in or eat it in seafood and it causes brain and nerve damage.

Also found were polyaromatic hydrocarbons, or PAHs, which are produced by burning gasoline and garbage and which may cause cancer; flame-retardant chemicals called polybrominated dibenzodioxins and furans; and pesticides including DDT and chlordane.

The same group analyzed the breast milk of mothers across the United States in 2003 and found varying levels of chemicals, including flame retardants known as PBDEs. This latest analysis also found PBDEs in cord blood.

Slaughter had similar tests done on her own blood.

"The stunning results show chemicals daily pumping through my vital organs that include PCBs that were banned decades ago as well as chemicals like Teflon that are currently under federal investigation," she said in remarks prepared for the news conference.

"I have auto exhaust fumes, flame retardant chemicals, and in all, some 271 harmful substances pulsing through my veins. That's hardly the picture of health I had hoped for, but I've been living in an industrial society for over 70 years."

The Government Accountability Office issued a report on Wednesday saying the Environmental Protection Agency does not have the powers it needs to fully regulate toxic chemicals.

The GAO, the investigative arm of Congress, found that the EPA's Toxic Substances Control Act gives only "limited assurance" that new chemicals entering the market are safe and said the EPA only rarely assesses chemicals already on the market.

"Today, chemicals are being used to make baby bottles, food packaging and other products that have never been fully evaluated for their health effects on children -- and some of these chemicals are turning up in our blood," said New Jersey Democrat Sen. Frank Lautenberg, who plans to co-sponsor a bill to require chemical manufacturers to provide data to the EPA on the health affects of their products.