Preventing Welding Flashback Oxy-acetylene torches have been used for many years for cutting, welding, brazing, and heating of metals. The equipment used today is safe, but every year, hundreds of employees are injured or die as a result of improper use. Knowledge and precautions can prevent fires and violent explosions. Gas Pressure: One cause of fires and explosions is high acetylene pressure. When more than 15 pounds of pressure is used, acetylene becomes unstable and decomposes explosively. This is the major reason for using other fuel gases such as MAPP, propylene, propane, and natural gas which may be safely used at higher...