Compressed gas cylinders can be extremely hazardous, not only because of the contents of the cylinders, but because of the pressure of the gases within the cylinders, so there is a dual concern. When a cylinder is compromised, there’s worry about how the container itself may behave, but also about the potential from harm from whatever chemical is stored inside.

Cylinders are relatively heavy and usually full of dangerous gas that’s under a lot of pressure—working with compressed gas cylinders means having an awareness of an inherently dangerous situation, and understanding the complexities to mitigate for. The most recognizable, feared scenario involving compressed gas tanks involves the rapid loss of pressurization that may turn a vessel into a missile-like device with ballistic properties, occurring when the cylinder has ruptured in some fashion. That’s why the federal Office of Compliance once referred to pressurized cylinders as “the loaded weapon in your workplace.”

In order to recognize the hazards posed by compressed gas cylinders, you must first be able to recognize the specific parts of the cylinder and have a general knowledge of how these things work. Compressed gas cylinders can pose the hazard of an explosion when the metal pressure vessel fails. A common factor in that scenario is the misuse or abuse of the cylinder or valve while it is under pressure. Another hazard is the sudden release of pressure from the cylinder, as mentioned above.

Compressed gas cylinders may contain many types of gases. Some of the more common gases used in pressure cylinders include those that are combustible, flammable and/or explosive, poisonous, or that are corrosive, reactive, or inert. Compressed gas cylinders could also contain gases that share a combination of some of these characteristics. It is important to know what is inside, so accurate labeling, marking, and dating are each critical precautions for safety.

Let’s run through some basics.

Only properly trained personnel with the appropriate personal protective equipment should handle compressed gas cylinders because the release of these gases could result in injury or death from fire, explosion or exposure. If you are using compressed gases, you must be trained in the safe use of pressurized systems and the materials they contain. You should also be trained in all elements of your company's Hazard Communication Program and in the hazards and precautions associated with the materials you are using.

Before working with a compressed gas cylinder, always read the label. Make sure you know what’s in it, what you’re working with. The contents of any compressed gas cylinder must be clearly identified. Don’t accept a cylinder for use that does not legibly identify the contents.

Gas identification may be stenciled or stamped on the cylinder. Gas may also be identified on a label that is solidly attached to the cylinder. Commercially available tag systems may also be used for identification.

Do not rely on the color of the cylinder for identification. Color coding is not reliable because cylinder colors may vary with supplier, and because these containers are reused. Also, do not rely on the cylinder cap label because the caps are interchangeable. If the cylinder label becomes unclear, mark the cylinder “contents unknown” and return it to the supplier—it’s just safer that way. Don’t let convenience cause problems for you when working with a vendor.

Before using compressed gas cylinders, you should take two basic precautions. First, you should be working in a well-ventilated area. Second, make sure the cylinder is equipped with the correct regulator; heck the regulator and cylinder valves for grease, oil, dirt, or solvent, and either remove what you find or do not use the contaminated component.

Another important thing to remember is that oxygen is not compressed air. Never use oxygen as a substitute for compressed air for running pneumatic tools, in oil heating burners, to start internal combustion engines, to blow out pipelines, to dust off clothing or equipment, or to create pressure for ventilation. Do not smoke when oxygen and fuel gases are present as a fire could result.

Store compressed gas cylinders in a well-ventilated, cool, dry area. Be sure that cylinders are stored where they are protected from unauthorized access and are protected from the elements. Store them away from direct sunlight, where their temperature will not exceed 125 degrees Fahrenheit.