Tank car unloading
Pipeline and Hazardous Materials Safety Administration · Sep 24, 2007 · Reference No. 07-0136
Interprets: 49 CFR § 174.67
Reggie’s quick take
A company asked whether unloading rail tank cars into fixed storage tanks at a terminal counts as transloading under the Hazardous Materials Regulations. In the scenario, the cars are emptied into those tanks, then sent back as residue cars, and tank trucks are loaded from the storage tanks. The agency said yes, this is not transloading, because fixed storage tanks are neither bulk nor non-bulk packaging. So the rack operation is generally not subject to the attendance rules in § 174.67. Section 173.31(g) still requires protection of the operation while the tank cars are connected and product is being unloaded.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your July 6, 2007 letter concerning the applicability of the Hazardous Materials Regulations (HMR: 49 CFR 171-180) to tank car unloading. In your letter, you present the following scenario:
You state that railroad tank cars are unloaded into fixed storage tanks at a terminal. After unloading, the tank cars are disconnected and prepared for return transit as residue cars. Tank trucks are then loaded from the fixed storage tanks. You state that this specific unloading rack operation is not a transloading operation as defined in the HMR because the tank cars are unloaded into fixed storage tanks rather than non-bulk or bulk packaging, and, therefore is not subject to the tank car unloading requirements specified in § 174.67. You ask whether your interpretation is correct.
The answer is yes. As defined in § 171.8, transloading means the transfer of a hazardous material by any person from one bulk packaging to another bulk packaging, from a bulk packaging to a non-bulk packaging, or from a non-bulk packaging to a bulk packaging for the purpose of continuing the movement of the hazardous material in commerce. The material in your scenario is being transferred from a bulk packaging to fixed storage tanks. Fixed storage tanks do not meet the definition of non-bulk or bulk packaging nor does this operation meet the definition of transloading. Therefore the rack operation you described is not generally subject to the tank car loading requirements (e.g., attendance) specified in section 174.67. However, the requirements of Section 173.31(g) would still require protection of the operation while tank cars are connected and product is being unloaded.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.