Interpretation Response #06-0283
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
April 3, 2007
Mr. Dennis Coleman Reference No. 06-0283
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.
John A. Gale
Chief, Standards Development
Office of Hazardous Materials Standards
173.11 (a), 173.22
173.116, 173.133 (b)(1)
|§ 173.116||Class 2-Assignment of hazard zone|