With one seat on FERC's nominally five-member panel empty for more than three months and another due to be vacated this summer, natural gas and oil organizations are anxious for the White House to nominate new commissioners.

"The lack of a full Commission can delay the approval of pending projects, such as natural gas infrastructure projects, thereby hindering the advancement of critical infrastructure," members of the Natural Gas Council (NGC) wrote in a letter sent to President Trump Monday.

The Federal Energy Regulatory Commission currently has four members -- Chairman Neil Chatterjee and Bernard McNamee, who are Republicans, and Cheryl LaFleur and Richard Glick, who are Democrats.

Commissioner and former Chairman Kevin J. McIntyre, who had been battling cancer since 2017, died Jan. 2. LaFleur recently announced that she will step down at the end of her term on June 30. McNamee's term expires in 2020; Chatterjee's in 2021; and Glick's in 2022.

The NGC letter comes only days after Trump signed a pair of executive orders to expedite approval for a growing backlog of natural gas pipelines, liquefied natural gas facilities, oil infrastructure and related projects. But, according to NGC's members -- the American Gas Association, American Petroleum Institute, Independent Petroleum Association of America, Interstate Natural Gas Association of America, and Natural Gas Supply Association -- that effort could be hindered by less than a full contingent at FERC.

"A full complement of FERC commissioners is critical to achieve the administration's goal to streamline the review and permitting of natural gas infrastructure projects," NGC said.

The White House has given no indication whom President Trump might nominate to replace McIntyre or LaFleur. By law, no more than three seats at FERC may be held by one political party, so speculation is that Trump would nominate a Republican first and then a Democrat when LaFleur leaves later this year.

Among the names floated as possible nominees have been Barry Smitherman, former Railroad Commission of Texas chairman and Texas Public Utilities Commission member; Patrick McCormick, former chief counsel for the Senate Energy and Natural Resources Committee; and Ellen Nowak, former chairwoman of the Wisconsin Public Service Commission, all of whom were also reportedly under consideration for FERC in 2017. Also reportedly under consideration is David Hill, former general counsel for NRG Energy.