Unlike many natural, untreated fabrics, polyester is not flammable and does not ignite easily, according to Fabric Finishing Partners. Once ignited, however, the synthetic fabric melts and is capable of severely burning skin.
Polyester blends are even more potentially dangerous as the combination of melting fabric with natural fabric that burns at a high rate is likely to cause serious burns, reports Fabric Finishing Partners. Natural fabrics, such as cotton, silk and linen, ignite more easily and burn more quickly than synthetic fabrics. Wool is the exception. It is more challenging to light and burns with a relatively low flame velocity.