Polyester is the most widely used synthetic fabric in the world — in clothing, bedding, upholstery, outdoor gear, and industrial applications. Understanding its fire behavior is important for anyone making safety decisions about clothing or home furnishings.

Polyester is flammable, but it behaves differently from cotton or wool. Polyester melts before it burns, similar to nylon. It has an ignition temperature of around 482°F (250°C) for most formulations, and it will sustain combustion once ignited. The key hazard: burning polyester melts and drips, and those drops continue burning on contact — causing severe, adhesive burns to skin.

Polyester vs. Cotton in a Fire

Cotton ignites at a lower temperature (around 356°F / 180°C) and burns faster than polyester. However, cotton burns away from the skin while polyester melts onto it. For this reason, many fire safety experts consider polyester (and synthetics generally) more dangerous for clothing in high-heat environments, even though cotton is technically more flammable.

Blended fabrics — like cotton-polyester T-shirts — combine the worst of both: the cotton component burns, and the polyester melts. If you wear a 60/40 cotton-poly blend near heat, the fabric ignites easily (from the cotton) and then melts onto skin (from the polyester).

Flame-Retardant Polyester

Polyester can be treated with flame retardant chemicals to slow ignition and reduce flame spread. FR polyester is widely used in industrial workwear, children’s sleepwear, and upholstery. These treatments don’t make the fabric fireproof, but they significantly increase the time before ignition — giving more time to escape or react. FR treatments can wash out over time with repeated laundering, so follow care instructions carefully.

Polyester Bedding and Upholstery

Polyester fill in pillows, comforters, and stuffed furniture burns intensely once ignited and produces thick black smoke. In a house fire, burning synthetic bedding is a major contributor to smoke toxicity. Natural fiber or FR-treated bedding reduces this risk somewhat.

For related reading, see our article on nylon flammability and how cotton behaves in fire.