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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #19-0114

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

Interpretation Response Details

Response Publish Date:

Company Name: Entegris, Inc.

Individual Name: Mr. James V. McManus

Location State: CT Country: US

View the Interpretation Document

Response text:

May 6, 2020

Mr. James V. McManus
Principal Engineer
Dangerous Goods Safety Advisor
Entegris, Inc.
7 Commerce Drive
Danbury, CT  06810

Reference No. 19-0114

Dear Mr. McManus:

This letter is in response to your September 24, 2019, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to empty packagings. Specifically, you ask whether a 50-liter Department of Transportation (DOT) 3AA-2400 specification cylinder containing "UN 2199, Phosphine, 2.3 (poisonous gas), 2.1 (flammable gas)," residue is subject to the HMR after the cylinder is cleaned of residue and purged of vapors using a vacuum pump and nitrogen purging.

You state the 100 ppmv phosphine/nitrogen mixture within the cylinder has a calculated LC50 of 200,000 ppm and the pressure within the cylinder is less than 200 kPa (29.0 psig/43.8 psia) at 20 ºC (68 ºF).  You seek confirmation that the gas mixture you describe is not subject to the HMR.

Section 173.22 states it is the responsibility of the shipper to classify a hazardous material. However, based on the information you provided, this Office agrees that a phosphine/nitrogen mixture within a cylinder that has a calculated LC50 of 200,000 ppm and a pressure less than 200 kPa does not meet the definition of a Division 2.1 or Division 2.3 material under the HMR. Paragraphs (b)(2)(ii) and (iii) of § 173.29 state a packaging that is sufficiently cleaned of residue and purged of vapors to remove any potential hazard, or that is refilled with a material that is not subject to the HMR to the extent that any residue that remains in the packaging no longer poses any hazard, is not subject to the requirements of the HMR.

I hope this information is helpful.  Please contact us if we can be of further assistance.


T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

173.22, 173.29

Regulation Sections

Section Subject
173.22 Shipper's responsibility
173.29 Empty packagings