The handling of compressed gases must be considered more hazardous than the handling of liquid and solid materi­als. Compressed gases by their nature are hazardous, according to the U.S. Dept. of Transportation, which offers the following guideline for safe han­dling of compressed gas cylinders.

They are capable of creating environ­ments that are either flammable, oxygen enriched, or oxygen deficient. High pressure, low flash points for flamma­ble gases, low boiling points, and no vi­sual and odor detection are all hazards.

Hazards may arise as a result of equipment failure and leakage from sys­tems that are not pressure-tight. Also, improper pressure control may cause unsafe reaction rates due to poor flow control.

Diffusion of leaking gases may cause rapid contamination of the atmosphere, giving rise to toxicity, anesthetic effects, asphyxiation, and rapid formation of ex­plosive concentrations of flammable gases. The flash point of a flammable gas under pressure is always lower than ambient or room temperature. Leaking gas can therefore rapidly form an ex­plosive mixture with air.

Low-boiling point materials can cause frostbite on contact with living tissue. This is common among cryogenic liq­uids but it also can result from contact of the liquid phase of liquefied gases such as carbon dioxide, fluorocarbons, and propylene. Some compressed gases are similar to other chemicals in that they are corrosive, irritating, and highly reactive.  

Cylinder Markings

A. Compressed gas cylinders shall be legibly marked for the purpose of identifying the gas content with ei­ther the chemical or the trade name of the gas. These markings shall be by means of stenciling, stamping or labeling and shall not be readily re­movable. Whenever practical, the markings  be located on the shoulder of the cylinder.
B. Compressed gas cylinders will be inspected twice per calendar year in accordance with the following guidelines. Any cylinders failing to meet these guidelines will be removed from service.
1. 1. Dents — Dents are deformations caused by the cylinder coming in contact with a blunt object in such a way that the thickness of metal is not normally impaired. Only cylinders that have major dents that do impair the metal wall will be removed from service.
2. 2. Cuts, gouges and digs — These are deformations caused by contact with a sharp object in such a way as to cut into or upset the metal of the cylinder, decreasing the wall of thickness at that point. Cylinders that have cuts, gouges and digs that decrease the thickness of the metal wall will be removed from service.
3. 3. Corrosion and pitting — Cylinders that have corrosion and pitting in the cylinder involving the loss of wall thickness caused by a corrosive media will be removed from service.
4. 4. Bulges — Cylinders that have definite bulges will be removed from service.
5. 5. Neck — The cylinder neck will be examined for serious cracks, folds and flaws. Neck cracks are determined by testing with a soap solution. Cylinders found to have a serious neck crack will be removed from service.
6. 6. Foot-Ring and Head-Ring — Cylinders will be removed from service when the head-ring and/or foot-ring becomes so distorted that they no longer 1) maintain the cylinder in a normal upright position or 2) when the head-ring becomes so distorted it no longer adequately protects the valve and the neck area of the cylinder. The use, storage and handling of compressed gas cylinders presents two types of hazards.

First is the chemical hazard associated with the cylinder contents (corrosive, toxic, flammable, etc). Second, is the physical hazard represented by the cylinder being under pressure. Mishandled cylinders may rupture violently, release their hazardous contents or become dangerous projectiles.
The following paragraph illustrates the deadly nature of compressed gas cylinders.

An industrial explosion, which killed three people and injured 30 others, involved a single oxygen bottle. The top of the bottle was found high in one of their structures, the bottom buried deep in the ground, and the center portion disintegrated in the form of shrapnel, blowing off arms, legs and decapitating one of the victims. No one could imagine a single oxygen bottle doing this much damage.

To use, handle, and store cylinders, it is important to know and follow these safety steps:
. • Read the cylinder label to identify the contents — the color of the cylinder is not always an identifying factor;
. • Read the Material Safety Data Sheet (MSDS) and know the safety and first-aid requirements;
. • Identify the hazards associated with the contents and take the precautions listed on the label/MSDS;
. • Report unlabeled cylinders to a supervisor so that the supplier can be contacted to provide the correct information or pick up the cylinder;
. • Never expose a cylinder to spark-pro-ducing electrical tools, cigarettes or open flames;
. • Cylinders must be secured at all times to prevent falling over (chain, plastic coated wire cable, commercial cylinder strap);
. • Never attempt to make repairs to cylinders or valves;
. • Do not use cylinders as rollers;
. • Do not drop cylinders or allow them to bump violently against each other;
. • Do not permit cylinders to become part of an electrical circuit;
. • Never accept cylinders if they have an expired hydrostatic pressure test date;
. • Do not use grease or oil on oxygen cylinders — do not use greasy or oily gloves on oxygen cylinders;
. • Do not use cylinders that are dented, cracked, or have other visible damage;
. • Always move cylinders with a suitable hand truck;
. • Always store cylinders in an upright, secured position, and in an adequately ventilated area;
. • Cylinder caps should be secured, straight, and hand tight, whether the cylinder is full or empty;
. • Never store a cylinder near an actual
or potential source of heat;
. • Never store a cylinder where it will be exposed to weather extremes;
. • Never store cylinders where heavy objects could fall on them;
. • Never store acetylene or flammable gas cylinders on their sides (upright only);
. • Do not store oxygen cylinders within 20 feet of fuel gas cylinders or highly
• Do not store cylinders containing flammable gases such as hydrogen or acetylene in close proximity to open flames or other ignition sources.
Empty cylinders should be:
. • Labeled as empty;
. • Stored with valve closed and cylinder cap secured;
. • Stored separately from full cylinders; and
*Returned with all original accessories. FSM