Some liquefied gases require special precautions. For example, when oxygen is handled, all combustible materials, especially oil or gases, should be kept away. Smoking or open flames should never be permitted where liquid oxygen is stored or handled; "no smoking" signs should be posted conspicuously in such areas.

Oxygen will vigorously accelerate and support combustion. Because the upper flammable limit for a flammable gas in air is higher in an oxygen-enriched air atmosphere, fire or explosion is possible over a wider range of gas mixtures.

Liquid oxygen or oxygen-enriched air atmospheres should not come in contact with organic materials or flammable substances. Some organic materials - oil, grease, asphalt, kerosene, cloth, tar, or dirt containing oil or grease - react violently with oxygen and may be ignited by a hot spark. If liquid oxygen spills on asphalt or on another surface contaminated with combustibles (for example, oil-soaked concrete or gravel), no one should walk on, and no equipment should pass over the area for at least 30 minutes after all frost or fog has disappeared.

Any clothing that has been splashed or soaked with liquid oxygen, or exposed to a high gaseous-oxygen atmosphere should be changed immediately. The contaminated systems should be aired for at least an hour until they are completely free of excess oxygen. Workers exposed to high-oxygen atmospheres should leave the area and avoid all sources of ignition until the clothing and the exposed area have been completely ventilated. Clothing saturated with oxygen is readily ignitable and will burn vigorously.

Finally, oxygen valves should be operated slowly. Abruptly starting and stopping oxygen flow may ignite contaminants in the system.