U.S. energy company New Fortress Energy Inc's permit to ship liquefied natural gas (LNG) by rail could expire on Nov. 30, environmental groups opposed to those shipments said on Nov. 22.

New Fortress wants to transport LNG from a liquefaction plant it is developing in Wyalusing in northeast Pennsylvania via truck or train to a port in Gibbstown, New Jersey.

The LNG would then be exported by ship from Gibbstown to customers in the Caribbean and elsewhere. The Gibbstown terminal is owned by Fortress Transportation and Infrastructure Investors LLC's Delaware River Partners LLC subsidiary.

New Fortress, however, has not yet made a final decision to build the Pennsylvania plant, which would liquefy natural gas from the Marcellus shale.

The U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA) issued the permit to New Energy's Energy Transport Solutions in December 2019.

Delaware Riverkeeper, an environmental group opposed to the LNG project, said in a release that New Energy must apply to renew the permit 60 days before expiration to prevent it from expiring.

Officials at New Fortress, PHMSA and Fortress Transportation were not immediately available for comment.

Delaware Riverkeeper said New Fortress continues to pursue the proposed Gibbstown LNG export terminal.

Even if LNG by rail does not work, New Fortress could still transport LNG to the port by truck, the environmental group said.

New Fortress said in federal filings that it spent about $159 million through the end of 2020 to develop the Pennsylvania facility.