The Chlorine Institute, Inc. — Hazardous Materials Safety Interpretation

Page 1F of Transportation U.S. Department 100 Seventh Street. S.w. Research and Washington, D C 20590 Special Programs Administration JUN 3 1998 Mr. John P. Aherne Director, Storage and Transport The Chlorine Institute, Inc. 2001 L Street, NW Washington, DC 20036-4919 Dear Mr. Aherne: This is in reference to your letter and a conversation with a member of my staff concerning inspection requirements for cargo tank motor vehicles in 49 CFR Part 180.407. Specifically, you ask for clarity pertaining to the frequency of the internal visual inspection for an MC 331 cargo tank in chlorine service. You read § 180.407(c) to require performance of the internal visual inspection every five years. Data available to this office indicate that chlorine is not corrosive to carbon steel. In the case of a specification MC 331 cargo tank in chlorine service, § 180.407(c) requires performance of a pressure test every two years. Because the pressure test procedure (see § 180.407(g)) calls for an internal visual inspection, also, the five-year retest interval specified in § 180.407(c) is not applicable to specification MC 331 cargo tanks in chlorine service. If you need further assistance, please contact us. Sincerely, Chomas G. Allan Senior Transportation Regulations Specialist Office of Hazardous Materials Standards#

Page 2THE CHLORINE INSTITUTE, INC., 2001 L STREET, N.W., WASHINGTON, D.C. 20036 - 4919 202-775-2790 Fax 202-223-7225 http : //www.cl2.com March 27, 1998 Norman E. Thogersen, Chairman John E. Fike, Jr., Vice Chairman Jennifer Karim Dr. Robert G. Smerko, President Exemptions and Regulations Termination Research and Special Programs Administration U.S. Department of Transportation. 400 Seventh Street, S.W. Washington, D.C. 20590 Dear Ms. Karim: This is a follow up to our telephone conversation on Friday, March 20, 1998 in which we discussed Question 49 of an RSPA document, dated September 30, 1993, entitled "Frequently Asked Questions Concerning Requirements Applicable to Cargo Tank Motor Vehicles." I have attached this document. We agreed that 49 CFR 180.407(c) requires an internal visual inspection for an MC 331 in chlorine service every five years and not every year as indicated in the answer to Question 49. I realize this is an old question and answer document, however it was recently sent on December 22, 1997 to Mr. Rich Ford of the Metropolitan Water District of Southern California, a member of the Chlorine Institute. I would be very appreciative if you could send me something in writing that I could forward to Mr. Ford so he could have written record that shows the information sent to him is not accurate. If necessary, you can call me at 202 872-4723. Thank you. Sincerely, Pack Cheme John P. Aherne Director, Storage and Transport Copy: Richard Ford, Metropolitan Water District of S. Calif. Enclosed: RSPA Q&A document dated September 30, 1993#