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Interpretation Response #99-0301

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date: 02-18-2000
Company Name: Shell Chemical Company    Individual Name: Mr. David J. Mashinski
Location state: TX    Country: US

View the Interpretation Document

Response text:

February 18, 2000


Mr. David J. Mashinski                        Ref. No. 99-0301
Transportation Safety and Regulations
Shell Chemical Company
910 Louisiana Street
Houston, Texas 77002-2463

Dear Mr. Mashinski:

This responds to your letter of October 26, 1999, requesting clarification of the attendance requirements for unloading tank cars under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).  Your letter describes a tank car steaming process during which vapors are vented through a valve that is connected via closed pipe to a permitted air pollution control device.  You ask whether this process must be attended in accordance with 174.67 of the HMR.

The answer is yes.  During a tank car steaming process that is conducted with an open valve or manway, the tank car must be attended.  However, when a tank car is connected to a steaming device that is not interconnected with or part of the unloading process or if the steaming process is conducted with all valves and manways closed, attendance is not required.

I hope this information is helpful.  If you have further questions, please do not hesitate to contact this office.



Thomas G. Allan
Senior Transportation Regulations Specialist
Office of Hazardous Materials Standards


Regulation Sections

Section Subject
§ 174.67 Tank car unloading