Interpretation Response #06-0283 ([ISOTECH Laboratories, Inc.] [Mr. Dennis Coleman])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: ISOTECH Laboratories, Inc.
Individual Name: Mr. Dennis Coleman
Location State: IL Country: US
View the Interpretation Document
Response text:
April 3, 2007
Mr. Dennis Coleman                  Reference No. 06-0283
  President
  ISOTECH Laboratories, Inc.
  1308 Parkland    Court
  Champaign,   IL 6 1821-1826 
Dear Mr. Coleman:
This responds to your letter dated December 21, 2006 regarding whether a sample mixture of natural gas containing a hydrogen sulfide (H2S) concentration level not exceeding 14% (on a molar basis) may be transported by all modes of transportation without labeling the sample toxic inhalation hazard.
Isotech Laboratories, Inc. (Isotech) analyzes natural gas samples for commercial consumers located in the United States and abroad. Samples are shipped to Isotech containing small amounts of H2S. Based on your review of the Class 2 assignment of hazard zones in §173.116(a) and your calculations according to §173.133(b)(1), you determined that the concentration level of H2S in a mixture of natural gas could reach 14% (on a molar basis) before being considered toxic-by-inhalation and requiring a 2.3 (Poison Gas) label. Specifically, you ask whether your calculated concentration level is correct; thus, allowing Isotech and its customers to ship natural gas samples containing an H2S concentration not exceeding 14% (on a molar basis) classed as Division 2.1 (Flammable Gas) and not Division 2.3 (Poison Gas), which is toxic-by-inhalation, requiring display of a POISON GAS label.
Under the Hazardous Materials  Regulations (HMR; 49 CFR Parts 171-180), it is a shippers responsibility to  classify a hazardous material (See §173.22). This Office does not perform that  function. As currently prescribed in the HMR, a material described as “Hydrogen  sulfide, 2.3, UN 1053” requires both Divisions 2.3 and 2.1 (Poison Gas and  Flammable Gas) labels, and is toxic-by-inhalation. Based on the information you  provided, it is our opinion that a sample mixture of natural gas containing a  hydrogen sulfide (H2S) concentration level  not exceeding 14% (on a molar basis) may be
  transported by all modes of transportation as a Division 2.1  (Flammable Gas) material without labeling the sample toxic inhalation hazard.
I hope this satisfies your inquiry. If we can be of further assistance, please contact us.
Sincerely,
John A. Gale
  Chief, Standards Development
  Office of Hazardous Materials Standards
173.11 (a), 173.22
  173.116, 173.133 (b)(1)