On 8 November 2021, the U.S. Department of Transportation’s (DOT) Pipeline and Hazardous Materials Safety Administration (PHMSA) published a Notice of Proposed Rulemaking (NPRM) to propose a temporary suspension of transport of liquid natural gas (LNG) by rail in certain DOT113 specification rail tank cars, previously authorized under the Trump Administration’s July 2020 rule (LNG by Rail final rule). Specifically, PHMSA is proposing to suspend LNG-by-rail transport under the LNG by Rail final rule while it "conducts a thorough evaluation of the HMR’s regulatory framework for rail transportation of LNG in a companion rulemaking under RIN 2137-AF54, and determines if any modifications are necessary." PHMSA is proposing to a add new special provision 439 to 49 C.F.R. § 172.102, which would prohibit LNG transportation in rail tank cars until PHMSA completes a separate rulemaking proceeding under RIN 2137-AF54 or until June 30, 2024, whichever is earlier.