FERC has denied a request filed earlier this year by three environmental groups to suspend construction of TransCanada Corp.’s Mountaineer Xpress and Gulf Xpress projects pending a rehearing, finding that the organizations failed to demonstrate irreparable injury.

A month after the Federal Energy Regulatory Commission issued certificates of public convenience and necessity for the projects, the Allegheny Defense Project, the Ohio Valley Environmental Coalition and the Sierra Club sought a rehearing and filed for the stay.

In support of their request, the groups said they have “members who live, work, recreate and enjoy quiet solitude along and in the streams, wetlands and forest that the project would harm.” But FERC said the groups failed to provide specific evidence.

“Instead, Allegheny catalogs the number of vegetated acres impacted by the projects, the number of water bodies that they would cross and the number of at-risk species affected,” the Commission wrote, referring to all three groups. “These generalized claims of environmental harm, however, do not constitute sufficient evidence of irreparable harm that would justify a stay.”

FERC also said the projects’ environmental impact statement addresses impacts to the environment and noted that the company is required to mitigate them.

Both projects would increase natural gas takeaway capacity from the Appalachian Basin. Mountaineer Xpress would expand the Columbia Gas Transmission system in West Virginia, while the Gulf Xpress would expand capacity on the Columbia Gulf System. The systems are expected to be in service later this year.