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Interpretation Response #19-0045

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

Interpretation Response Details

Response Publish Date:

Company Name: Maryland Department of Environment

Individual Name: Michael Polinski

Location State: MD Country: US

View the Interpretation Document

Response text:

January 09, 2020

Michael Polinski
Maryland Department of Environment
1800 Washington Blvd, Suite 105
Baltimore, MD  21230

Reference No. 19-0045

Dear Mr. Polinksi:

This letter is in response to your April 3, 2019, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the definition of a bulk packaging for a gas. Based on subsequent phone conversations, we have rephrased some of the details of your question. You describe two cylinders, i.e., ASME specification cylinder (similar to the DOT 4B specification) and DOT 4B, respectively, and indicate that both cylinders have a water capacity of 1000 pounds and a volumetric capacity of 120 gallons. You also indicate that both cylinders are filled with propane. You ask whether the cylinders are a bulk packaging or a non-bulk packaging.

A DOT 4B cylinder with a water capacity of 1,000 pounds or less is a non-bulk packaging. Per the definition of a bulk packaging in § 171.8, a cylinder with a water capacity greater than 454 kg (1,000 pounds) that is used as a receptacle for a gas, as defined in § 173.115 of the HMR, is considered bulk. Furthermore, in accordance with § 171.10, where metric units appear, they are considered the regulatory standard of the HMR. In this instance, the metric unit of 454 kg appears and thus is the standard; and converts to approximately 1,001 pounds of water. Therefore, provided the cylinder has a water capacity of not more than 454 kg, the cylinder meets the definition of a non-bulk packaging, regardless of the gallon conversion (e.g., 454 kg = ~119.8 gal).

Also, note the definition of bulk packaging is used for purposes of the HMR and only applies to packagings transported in commerce. The same principle would apply to an ASME specification cylinder with a described volumetric capacity of 120 gallons. However, only in some situations may an ASME specification cylinder filled with a hazardous material be offered into transportation in commerce.

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


Dirk Der Kinderen
Chief, Standards Development
Standards and Rulemaking Division

171.8, 173.115, 171.10

Regulation Sections

Section Subject
171.10 Units of measure
171.8 Definitions and abbreviations
173.115 Class 2, Divisions 2.1, 2.2, and 2.3-Definitions