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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 #24-0109

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

Interpretation Response Details

Response Publish Date:

Company Name: Shintech Louisiana

Individual Name: Chris Boggs

Location State: LA Country: US

View the Interpretation Document

Response text:

January 7, 2025

Chris Boggs
Safety Manager
Shintech Louisiana
PO Box 358
Addis, LA  70710

Reference No. 24-0109

Dear Mr. Boggs:

This letter is in response to your November 11, 2024, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to residue on the exterior of a package. You describe a scenario in which, during the loading or unloading of a product, some of the corrosive hazardous material (sodium hydroxide) spills onto the exterior of a tank car, specifically that the product drips onto its exterior surface. You state that before transportation begins the tank car is cleaned and treated to neutralize the spilled sodium hydroxide. However, this process leaves the paint on the tank car etched and discolored—i.e., it leaves a stain. You add that it is impracticable to repaint the exterior of the tank car after every loading/unloading and ask whether the discoloration (i.e., the stain) resulting from the cleaning and neutralization of the hazardous material is a "residue" that would be in violation of the general requirements for packages, as specified in § 173.24(b).

The answer is no. The term residue specifically refers to a hazardous material. Although defined in § 171.8 as contents inside the package, in the context of § 173.24(b)(1)-(4), residue means a hazardous material adhering to the outside of a package from spillage from either the package itself or in association with loading or unloading the package. Discoloration (i.e., staining) is not considered residue for purposes of § 173.24(b)(1)-(4). Provided that any remnants of the cleanup and neutralization of the spillage on the exterior of the tank car does not meet any HMR criteria for a hazardous material and the tank car otherwise conforms to all other applicable requirements under the HMR, the tank car may continue to be used in transportation.

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

Sincerely,

Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

171.8, 173.24(b), 173.24(b)(1)-(4)

Regulation Sections