A man returned from lunch and was preparing to use his oxygen acetylene fueled torch to work on his truck. He turned on the acetylene valve and approximately 30 seconds later, opened the valve on the oxygen bottle. The oxygen regulator exploded, causing a large fire ball to engulf the man’s torso and ignite his clothing. The man was hospitalized with second- and third-degree burns over 50 percent of his body.

Regulator fires are a nasty business. Fortunately, they do not occur frequently in the welding industry, but when they happen, the damage to property and personnel can be significant. According to OSHA, several people are killed or seriously injured each year as a result of an RBO explosion. A small number perhaps, in light of the thousands of people using oxygen regulators, but a significant event if it happens to you.

Regulator fires happen when high pressure oxygen passing through the intake valve comes in contact with contaminants on the valve. The high pressure passage of the oxygen through the narrow valve creates heat. Any flammable material on the valve, including dirt, oil, grease or other hydrocarbons, can ignite under this heat. The resulting fire often triggers an explosion, turning parts of the regulator into high-temperature projectiles.

To avoid this problem, the following welding safety procedures should always be followed:

1. Crack the oxygen cylinder valve before you attach the regulator. To do this, stand to one side or to the rear of the cylinder outlet. Open the cylinder valve slightly for an instant and then close it. This should clean accumulated dust and dirt from the valve.

2. Use only oxygen regulators to control oxygen supply. Switching regulators from non-oxygen use to oxygen use can introduce contaminants into the system. Be sure the valve is clean and free of grease and oil. Never use an oxygen regulator for other gases.

3. Before opening the cylinder valve, be sure the oxygen regulator pressure-adjusting screw is released. To do this, rotate the screw counter clockwise until it turns freely.

4. Stand to one side while opening the oxygen cylinder valve. Open the valve as slowly as possible until the high pressure gauge reaches cylinder pressure. Never open the cylinder valve suddenly, as sudden surges of high pressure can cause a blow out.