On Thursday, EPA Administrator Lisa Jackson resigned abruptly. The agency offered no explanation, and Jackson apparently isn’t leaving straight to another job. President Obama offered no explanation. While cabinet-level officers come and go at the change of a president’s term, her resignation came as a bit of a surprise.

It turns out that she is getting out of the job as her email alias scandal builds to a head. PJM columnist Chris Horner and the Competitive Enterprise Institute say that Jackson’s use of offsite email accounts are the reason for her sudden resignation.

Horner and CEI earlier this year had sued the EPA for documents pertaining to Jackson’s use of alias email accounts. She was said to operate under the name “Richard Windsor” — the use of those accounts has since drawn the scrutiny of Republican members of Congress, as well as triggered an audit by the EPA inspector general.

According to court documents, the EPA — represented by the Justice Department — two weeks ago agreed to release as many as 12,000 emails pertaining to the CEI request beginning by Jan. 14, at a rate of 3,000 documents per month. The court accepted the schedule last week.

Horner said the increased scrutiny on the alias account, coupled with what those emails might contain regarding the administration’s alleged “war on coal,” likely contributed to Jackson’s announcement Thursday.

“She, by her action, told us that these are records she doesn’t want the people to see,” Horner said.

President Obama, in a written statement, made no reference to the emails.

Of course he made no references to “Richard Windsor” or Jackson’s concerted effort to keep her authoritarian deliberations off the official books. He leads the most transparent administration evah, after all. He can’t just go around telling the American people what’s really going on behind the scenes, can he?