Fire blankets are used to extinguish small fires by depriving them of oxygen. They can be made from a variety of materials but they are always flame retardant or resistant.
Fiberglass is a fire-resistant material made from finely woven fibers of glass. Fire blankets made from fiberglass are most suitable to household fires that may start on clothing or in the kitchen.
Fire blankets made from wool are often treated with a flame retardant. They are usually kept on hand in laboratories and industrial environments where chemical and electrical fires are more likely.
Some newer fire blankets like the Titan21 are made from 100 percent cotton and treated with a nontoxic and biodegradable fire inhibitor instead of potentially harmful flame retardants.
Asbestos is a mineral fiber that is very resistant to heat and fire, so it was frequently used in fire blankets. Deteriorating asbestos is very dangerous and causes significant damage when inhaled, so asbestos fire blankets should be disposed of with extreme caution and replaced with a safer material.