Cryogenic Air Separation Units (ASITs)frequently supply oxygen and nitrogen to chemical, petroleum and manufacturing customers. Typically the ASU is located remotely from the use point, and the products are supplied via a pipeline. This paper provides the basic design and operating methods to safely operate an ASU. The four primary hazards associated with these units are: 1) the potential for rapid oxidation, 2) interfaces between the ASU and the downstream systems, 3)pressure excursions due to vaporizing liquids, and 4) oxygen enriched or deficient atmospheres. Requirements for safely handling oxygen within the air separation facility and at the product use point are also discussed in this paper.