After a finals-crunch all-nighter, students should try to make it back to their beds rather than crash on the couch for a cat nap.

An alarmingly large portion of consumer couches use foam padding containing flame-retardant chemicals that are considered probable human carcinogens, according to a study conducted by Heather Stapleton, associate professor of environmental chemistry at the Nicholas School of the Environment. Tris—a chemical that was used in infant pajamas in the 1970s but was phased out of usage because of said carcinogenic risks—was among the chemicals found in the couch cushions.

Another chemical found in 17 percent of the 102 couch foam samples studied was pentaBDE, which is a banned substance in 172 countries and 12 U.S. states. Studies have suggested that PentaBDE chemicals can affect brain development and cause problems with endocrine activity, and that early exposure to infants can cause low birth weight, lowered IQ and impaired motor and behavioral development.

Forty-one percent of the couch samples in the study, which was published in Environmental Science and Technology, contained Tris, and Tris and pentaBDE were the only flame retardants found in couches manufactured prior to 2005. More than half contained flame-retardants that are potentially harmful to humans or have not been thoroughly tested for human safety.

Information about the type of flame retardants used can get lost in the production chain by the time the foam reaches the furniture manufacturer, making it difficult to track the exact chemicals used.

If it is any consolation, the couches with flame-retardants are tested to withstand at least 12 seconds of small flame exposure without igniting.