This publication applies to firms that engage in the filling, repackaging, transfilling, mixing, and/or relabeling of compressed medical gases (CMG) that are classified as drugs by the U.S. Food and Drug Administration (FDA) and applicable state agencies. It describes the minimum requirements for manufacturing CMG and is intended to aid the manufacturer in complying with the applicable regulations of the FDA and various state agencies, e.g., departments of health and boards of pharmacy. It contains the information that should be addressed in a firm's standard operating procedures (SOP). It may not contain the information necessary to comply with all federal and state regulations, so it should be used in conjunction with other compliance publications and guidelines.