Can oxygen and acetylene cylinders be stored on a welding cylinder carrier when not in use?

At 1910.253(b)(4)(iii), OSHA states that “Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet (6.1 m) or by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.” However, in general industry settings, if the cylinders are attached to a cart and with regulators connected for use, they are not “in storage” and can stay that way indefinitely and do not have to be separated.

A September 9, 1993, Letter of Interpretation explains OSHA’s views on cylinders being connected for use.