The chemical is what turns the skin brown. Potential risks were documented in 10 lab studies, which were obtained by ABC News. It should be noted that these tests were not conducted on human subjects.
The studies revealed that even though the FDA claims the chemical should not be inhaled or ingested, rules are not enforced in salons. The chemical, called DHA, is only approved for external use.
Dr. Lynn Goldman, the dean of George Washington University's School of Public Health says DHA is ending up in the respiratory system, and spray tanners should be concerned for the potential of lung cancer. She says the whole practice needs further investigation.
Goldman was one of six medical experts who showed concern over DHA's effects after reviewing the studies. Another expert called the chemical a "potential human health hazard," while another said that "it can cause DNA damage," which could lead to birth defects.
The FDA is clear that DHA should not be ingested or inhaled, telling consumers to protect their eyes, nose and lips.
However, in an undercover investigation, ABC News found workers at dozens of salons discouraged wearing any protective gear. Most salon workers just said to hold your breath and close your eyes.
Some salons even claim on their websites that you can eat DHA and that it is "food grade" and "approved for ingestion by the FDA." However, these salons are mixing up two completely different kinds of DHA. Both have the same abbreviated name, but one tans your skin and the other is a health supplement.
Joe Levy, the industry man in charge of educating U.S. tanning salons, was contacted about the studies. He said he had not heard of such studies before.
ABC News contributed to this report.