BERKELEY, CA — Chlorinated Tris (TDCPP) has been officially listed as a cancer-causing chemical by the State of California on the Proposition 65 list of harmful chemicals. The chemical is the most commonly used flame retardant in flexible polyurethane foam for U.S. upholstered and juvenile furniture.

In a recent risk assessment, TDCPP was found to cause malignant and benign liver and kidney tumors in rats. The chemical was also found to be structurally similar to TDBPP and TCEP, other halogenated phosphotriester carcinogens on the Prop 65 list. Usage of the TDCPP chemical in baby pajamas had been stopped in 1977 over concerns of its carcinogenicity.

Although placement on the Prop 65 list will not ban TDCPP (Tris 1,3-dichloro-2-propyl) from use, it will result in labeling requirements for consumer products. Under the rule, companies are required to provide a "clear and reasonable" warning before knowingly and intentionally exposing anyone to a listed chemical. The warning can be done in a variety of methods, including labeling on a consumer product, posting of signs in the workplace, or publishing notices. Once a chemical is listed, companies have 12 months to comply with warning requirements. The California Office of Environmental Health Hazard Assessment, part of the California Environmental Protection Agency, oversees the Prop 65 program.

The State of California is not the only entity to question the usage of TDCPP in consumer products. In 2006, the Consumer Product Safety Commission released a Risk Assessment of Flame Retardant Chemicals in Upholstered Furniture Foam, which included chlorinated Tris. The report found that the treated foam could present a hazard, based on both cancer and non-cancer end points. The CPSC also estimated that children’s exposure to TDCPP from treated furniture was five times higher than the agency’s acceptable daily intake.