This 3-part document gives requirements and recommendations for the selection and qualification of carbon and low-alloy steels, corrosion-resistant alloys, and other alloys for service in equipment used in oil and natural gas production and natural gas treatment plants in H2S-containing environments, whose failure could pose a risk to the health and safety of the public and personnel or to the environment. It can be applied to help to avoid costly corrosion damage to the equipment itself. NACE MR0175/ISO 15156 consists of three standards, available as a complete package: Part 1: General principles for selection of cracking-resistant materials; Part 2: Cracking-resistant carbon and low alloy steels, and the use of cast irons; Part 3: Cracking-resistant CRAs (corrosion-resistant alloys) and other alloys.