The State Department said Thursday that Secretary of State Rex Tillerson has recused himself from issues relating to TransCanada’s application for a permit to build the Keystone XL pipeline through the Midwest. Greenpeace and other watchdogs had warned of a potential conflict of interest, given Tillerson’s previous role as CEO of ExxonMobil. Katherine McManus, a legal adviser for the State Department, said Tillerson recused himself from the matter in February. “He has not worked on that matter at the Department of State, and will play no role in the deliberations or ultimate resolution of TransCanada’s application,” McManus wrote to activists, Reuters reported. It was not clear why the State Department did not announce Tillerson’s recusal in February. ExxonMobil stands to benefit from TransCanada’s participation in the pipeline, as it has investments in Canadian oil sands. In 2015, then-President Barack Obama rejected TransCanada’s bid to build the 1,179-mile pipeline; the company re-applied in January after President Trump took office and backed the multibillion-dollar project. While still at ExxonMobil in 2015, Tillerson had spoken out in favor of the pipeline, saying it would give the U.S. a competitive edge and increase energy security. But in a letter to McManus in January, he vowed to recuse himself “from participation in any particular matter involving specific parties in which I determine that a reasonable person with knowledge of the relevant facts would question my impartiality in the matter, unless I am first authorized to participate.” The pipeline, which would run through Canada and the U.S., requires State Department approval because it crosses an international border.