Hazardous Materials Regulations: Aluminum Cylinders Manufactured of Aluminum Alloy 6351-T6 Used in SCUBA, SCBA, Carbon Dioxide, and Oxygen Service-Revised Requalification and Use Criteria

Summary: On September 10, 2003, the Research and Special Programs Administration--the predecessor agency to the Pipeline and Hazardous Materials Safety Administration published a notice of proposed rulemaking (NPRM) to propose an inspection and testing program for early detection of sustained load cracking in certain cylinders manufactured with aluminum alloy 6351-T6. Based on comments received in response to that NPRM, we are proposing to adopt a maximum service life for cylinders manufactured with aluminum alloy 6351-T6 and to prohibit the use of these cylinders after the expiration of their maximum service life.