A brake pad is held together by resins. These resins need heat and pressure to cure. When the resins cure, the friction material becomes stronger. But, the curing process produces gases and smells. These gases cause brake fade and often the “new brake pad smell.”
Some manufacturers will scorch their pads. This involves extreme heat and pressure. This will help to give the pad’s initial 1 to 2 mm of material on the face an increased ability to bed and transfer a layer of friction material to the rotor. This means less time is needed to be spent test driving the vehicle to seat the pad after installation.
During the scorching process, the pad will emit gases. You might smell these gases if you manage to overheat a set of brakes. At this plant, the gases are burned in an afterburner till they are rendered harmless. These gas bill for this process is very expensive.