U.S. Department of Transportation
Pipeline and Hazardous Materials Safety Administration
400 Seventh Street, S.W.
Washington, D.C. 20590

JUL 20, 2006

Guidance and Criteria for the Competent Authority Numbering System

At the beginning of 2000, it became necessary to update the Competent Authority (CA) numbering system from the seven-digit sequence to the current 10-digit sequence.  The old seven-digit number (and in a few cases, nine-digit number) and the new 10-digit number are interchangeable.  It is not necessary to apply for a new number and the old number is still valid.  All CA's issued by the Approvals Office will contain the new 10-digit number.  If you company is using packagings, labels, and/or stamps with the old number, you may continue to use them when practicable.

[signed, refer to the PDF version]

Dr. Richard Tarr
Acting Chief, Approvals
Office of Hazardous Materials Special Permits and Approvals