PHMSA: Special Permit Sought to Ship Cryogenic Ethane By Rail

Written by Marybeth Luczak, Executive Editor
DOT-113C120W9 LNG tank car. Chart Industries photo

DOT-113C120W9 LNG tank car. Chart Industries photo

Gas Innovations LNG Refrigerants Inc. is seeking authorization to transport cryogenic ethane via rail in DOT-113C120W9 and DOT-113C120W tank cars, according to the Pipeline and Hazardous Materials Safety Administration (PHMSA). PHMSA, in consultation with the Federal Railroad Administration (FRA), is reviewing the special permit application and requesting comments on it, since it “raises issues similar to the transportation of liquefied natural gas (LNG) by rail, a matter for which multiple rulemakings are currently pending at the agency.”

“Cryogenic ethane is not currently allowed to be shipped in DOT 113 rail tank cars,” PHMSA reported in the Dec. 5 edition of the Federal Register (download below). The Hazardous Materials Regulations (HMR; 49 CFR parts 171-180) only allow for transport of cryogenic (or refrigerated) ethane in cryogenic truck trailers designated MC 331 or MC 338 under 49 CFR 173.315 and in UN T75 portable tanks in the 49 CFR 172.101 Hazardous Materials Table (special provisions column), according to the agency.

Gas Innovations LNG Refrigerants Inc. on Aug. 20, 2021, submitted an application for a special permit under § 107.105, PHMSA reported. It is looking to transport cryogenic ethane via rail from Marcus Hook, Penn., to locations along the Gulf Coast of the United States, Mexico and Canada. “Final destinations would be points in proximity to petrochemical or LNG liquefication facilities where the ethane would receive further processing,” according to PHMSA. “Gas Innovations explains in its application … that ethane is a non-volatile organic compound that is more stable than ethylene, a material that is currently authorized for transportation by DOT-113C120W rail tank car under the HMR. Gas Innovations further states that, compared to ethylene, ethane has a lower vapor pressure, lower flammability in air, and a higher ignition temperature. Gas Innovations asserts that transport of cryogenic ethane is safer than transport of cryogenic ethylene. Gas Innovations explains that transportation of cryogenic ethylene is authorized in DOT-113C120W9 and DOT-113C120W rail tank cars consistent with the specifications set forth in 49 CFR part 179, subpart F which specify the design and construction requirements for cryogenic liquid tank car tanks. Finally, Gas Innovations notes that it has experience in the transportation of liquefied petroleum and other cryogenic products in rail tank cars. Gas Innovations believes that the lower risk profile of ethane compared to ethylene, together with the company’s experience and expertise moving cryogenic products by rail tank car, will allow them to transport cryogenic ethane at the same level of safety under a special permit compared with what is currently authorized for rail transportation of cryogenic ethylene under the HMR.”

Because the proposed special permit “raises similar considerations as the transportation of LNG and the subject of PHMSA’s Notice of Proposed Rulemaking: Suspension of HMR Amendments Authorizing Transportation of Liquefied Natural Gas by Rail (Docket No. PHMSA-2021-0058),” PHMSA is requesting comments on the application and, if it were to be approved, “any specific operational controls which should be added to enhance safety and environmental impacts.”

Comments are due by Jan. 4, 2023, but PHMSA reported it would “consider late-filed comments to the extent possible.”

PHMSA in late 2021 proposed a temporary suspension of its regulations authorizing the transportation of LNG by rail. The move prompted not only the Railway Supply Institute (RSI) to weigh in, but also the Republican members of the House Transportation and Infrastructure Committee and a coalition of attorneys general from 14 states and Washington, D.C.; all submitted comments on the agency’s Notice of Proposed Rulemaking.

PHMSA, in coordination with FRA, proposed the suspension “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,” the agency wrote in 2021. “Transportation of LNG by rail tank car has not occurred and there is considerable uncertainty regarding whether any would occur in the time it takes for PHMSA to consider potential modifications to the existing, pertinent HMR requirements. However, PHMSA’s proposed temporary suspension of the HMR provisions authorizing transportation of LNG in rail tank cars guarantees no such transportation will occur before its companion rulemaking has concluded or June 30, 2024, whichever is earlier …”  

PHMSA explained that such a move would:

  • Avoid “any risks to public health and safety or environmental consequences (to include direct and indirect greenhouse gas (GHG) emissions) that are being evaluated in the companion rulemaking and in ongoing research efforts undertaken in collaboration with FRA and external technical experts.”
  • Assure “timely implementation of any mitigation measures and operational controls for rail tank car transportation of LNG identified in the companion rulemaking or those ongoing research efforts.”
  • Reduce “the potential for economic burdens by ensuring that entities avoid ordering rail tank cars compliant with the current requirements when the companion rulemaking may adopt alternative requirements. …”
  • Enable “meaningful opportunity for consideration of the perspectives of diverse stakeholders.”

PHSMA’s comment review is still under way. 

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