The flammability of fabric can be drastically reduced through the use of fire retardants. Many natural fibers, including cotton, can be topically treated with a chemical that reduces the fabric’s flammability to the extent that it becomes nearly non-combustible. During a fire, the chemical reacts with the gases and tars generated naturally by the fabric, converting the gases and tars to carbon char, thus drastically slowing the fabric’s burning rate.

Some polyester fabrics are considered permanently fire retardant. This is because fire retardant properties are built directly into the molecular structure of the fibers. Fabrics manufactured utilizing Trevira and Avora polyester fibers are considered inherently or permanently fire retardant[citation needed]. Other synthetic fabrics may be considered durably fire retardant, fire retardant, or non-fire retardant. Durably fire retardant refers to a process in which polyesters are chemically treated during the manufacturing process with a non-water soluble chemical. In other cases, synthetic fabrics may be topically treated with chemicals after the manufacturing process (in the same manner as natural fibers such as cotton), or may be untreated (or untreatable) and therefore considered non-fire retardant.

Aramid, like Twaron is used in modern fabrics to withstand high temperatures in industry and fire-fighting.