Such substances include lead and byproducts of secondhand smoke.
Federal health officials call the report's findings "an astonishing public health achievement."
In the early 1990s, 4.4-percent of the nation's children between the ages of 1 and 5 had raised lead levels. The latest survey showed a drop in those levels to 1.6 percent between 1999 and 2002.
The report suggests more research is needed on the health effects of low levels of exposure to the metal cadmium.
But, the Pesticide Action Network North America says the CDC only tested for a "really small slice" of chemicals in the environment. A leader of the group says the CDC tested for just 43 pesticides in the report - but more than 1,200 are registered with the Environmental Protection Agency.
Margaret Reeves of the Pesticide Action Network says, "This study highlights the tip of a toxic iceberg. (The) CDC evaluated only a fraction of the total number of pesticides used every day in agricultural fields, homes and gardens and found many of these toxic chemicals present in our bodies."
