Hazardous chemicals enter the environment from the factories where they are made and added to a dizzying array of consumer products – including mattresses, computers, cookware and plastic baby cups – and from landfills overflowing with discarded products. They drift into homes from nearby agricultural fields and taint drinking water and food. Today, hundreds of industrial chemicals contaminate the blood and urine of nearly every person tested. Sometimes lower doses or levels of exposure to toxic chemicals are actually more dangerous than higher amounts.