This position statement describes CGA's position on the permanent marking of all-metal (monolithic) DOT cylinders. There are a number of marking methodologies that can harm compressed gas cylinders if not properly controlled, and some that should not be allowed. With the increase in the various means of marking cylinders (etching, laser, cutting, stamping, etc.) now available to manufacturers, inspection, and test facilities, it is necessary for the organization performing the marking to use such methods only when that process does not alter or degrade the safety of the compressed gas cylinder. Further, the cylinder manufacturer may use a marking means under its control knowing through a verification process that the marking process does not degrade the performance or safety of the cylinder.