According to the information, Diono car seats contain flame retardants. However, it's important to note that all Diono car seat fabrics are tested to ensure they do not contain any legally restricted or harmful flame retardants. The brand claims to use materials that meet federal flammability standards without adding chemical flame retardants. However, some tests have shown that certain Diono models may contain TDCPP, or "tris," a flame retardant that some consider toxic.