WASHINGTON — It was supposed to be a town hall meeting where Iowa ranchers could ask questions directly of Scott Pruitt, the head of the Environmental Protection Agency. But when the agency learned that anyone would be free to ask anything, they decided to script the questions themselves.

“My sincere apologies,” an E.P.A. official wrote to the rancher who would be moderating the event. “We cannot do open q&a from the crowd.” She then proposed several simple questions for him to ask Mr. Pruitt, including: “What has it been like to work with President Trump?”

Details about the December event, and dozens of other official appearances from Mr. Pruitt’s scandal-plagued first year at the E.P.A., have until now been hidden from public view as a result of an extraordinary effort by Mr. Pruitt and his staff to maintain strict secrecy about the bulk of his daily schedule.

But a new cache of emails offer a detailed look inside the agency’s aggressive efforts to conceal his activities as a public servant. The more than 10,000 documents, made public as part of a Freedom of Information lawsuit by the Sierra Club, show that the agency’s close control of Mr. Pruitt’s events is driven more by a desire to avoid tough questions from the public than by concerns about security, contradicting Mr. Pruitt’s longstanding defense of his secretiveness.