Hillary Clinton received a lot of criticism since it was revealed this week that she had never used an official State Department email account while she was Secretary of State, she instead used a private email account maintained by a contractor.

Green groups such as 350.org and Friends of the Earth have expressed dismay that communications concerning her review of the Keystone XL pipeline may never be available for public review. Greens have long been concerned by ties between the presumed Democratic Presidential candidate and the oil and gas industry.

Karthik Ganapathy, a spokesman for 350.org said, “People deserve to know if a Cabinet official tasked with overseeing the review process of a major project like Keystone XL, and who said she’s ‘inclined to approve’ the pipeline, is also trading emails with the American Petroleum Institute or setting up meetings with TransCanada.”

“This is deeply concerning,” said Ben Schreiber, the climate and energy program director for Friends of the Earth. “The total lack of transparency is a real red flag for us and adds to other concerns that we have about Clinton’s ties to the oil industry.” – As reported by the National Journal

Friends of the Earth filed Freedom of Information Act requests to see communications between State Department officials and lobbyists for TransCanada, the company proposing the Keystone XL pipeline. Those requests did not uncover any emails written to or from Sec. Clinton.