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Interpretation Response #02-0027

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

Interpretation Response Details

Response Publish Date: 02-22-2002
Company Name: Calvert City, KY Emulsions Plant, Air Products & Chemicals    Individual Name: A & Joe Campbell
Location state: KY    Country: US

View the Interpretation Document

Response text:

February 22, 2002

Mr. Joe Campbell                                Reference No. 02-0027
Process Engineer
Calvert City, KY Emulsions Plant
Air Products & Chemicals
246 Johnson-Riley Road
Calvert City, KY 42029

Dear Mr. Campbell:

This is in response to your January 28, 2002 letter concerning the monitoring of rail tank car unloading under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask whether the electronic monitoring system you describe in your letter would be adequate to meet the requirements of § 174.67(i) and electronic rail car unloading monitoring outlined in a formal interpretation of the regulations, 87-4-RSPA.

The system you describe includes a qualified, trained operator monitoring the unloading process via two video cameras, software that detects leaks through changes in the video image and physical conditions of the unloading process, and a system of ethylene vapor monitors.  The computer imaging and vapor detection systems are connected to alarms to alert the operator of a leak and will automatically shut-off the unloading system.  In addition, there is a hardwired shut­down switch in the control room that can be manually activated by the unloading operator.

The system that you describe appears to meet the 4 criteria outlined in the letter of formal interpretation, 87-4-RSPA:

  1. An employee is made responsible for unloading and is familiar with the nature and properties of the material being unloaded;
  2. The employee responsible for unloading is instructed in the procedures to be followed during unloading and in the event of an emergency, and has the authority and ability to halt the flow of product immediately and take emergency action;
  3. In the event of an emergency, the system must be capable of immediately halting the flow of product or alerting the employee responsible for unloading; and
  4. The monitoring device must provide immediate notification of any malfunction to the person responsible for unloading, or the device is checked hourly for malfunctions.

As you note in your letter, if the proposed non-human monitoring system becomes disabled or inoperable, the unloading operator must constantly observe the unloading operation.

I hope this satisfies you request.


Delmer F. Billings
Chief, Standards Development
Office of  Hazardous Materials Standards


Regulation Sections

Section Subject
§ 174.67 Tank car unloading