The vast majority of mass-produced furniture in America is coated in a variety of flame retardants. A new study recently attempted to ascertain what happens to those chemicals when they come into contact with the humans that sit, sleep and eat on the furniture.

According to a new study by research organization Silent Spring, Americans may be more exposed to flame retardant chemicals than previously thought. In testing urine samples of 16 California residents in 2011, researchers found evidence of six phosphate flame retardants (PFRs) -- likely absorbed into the body via house dust.

"We tested urine samples of California residents for biomarkers of six chemicals that have been rarely studied in the US, and we found all of them," researchers wrote in a press release. "This was the first time the known carcinogen, TCEP, was detected in Americans."

The Massachusetts-based research group, whose recent study was aided by scientists in Belgium, recommends consumers request furniture free of flame retardant chemicals. Other health groups make similar suggestions, warning that some studies suggest chemicals like TCEP, TDCIPP and other PFRs have cancer-causing properties.

"We might have been really naive about the health effects of these chemicals," Dr. Catherine Thomasson, executive director for Physicians for Social Responsibility, told the San Jose Mercury News.

"If you touch something (like a couch), then put food in your month, you've eaten (the chemicals)," Thomasson said. "These flame retardants stay in the fat of people. They don't leave the body very readily."

None of the chemicals detailed in the study are listed as carcinogens by the CDC or NIH, but California law includes a more expansive list of toxins banned from certain uses for their suspected role in enabling tumor growth. The law, called Proposition 65, bans both TCEP and TDCIPP from certain consumer products -- like children's pajamas.

But those chemicals and others aren't banned entirely, which is why they continue to be employed in furniture production and why they're showing up in people's bodies.

The new research was published this week in the journal Environmental Science & Technology.