Environmental Protection Agency officials posted another batch of Windsorgate emails Friday but the conservative think tank at the center of the scandal said today that missing from the release "are what should be the dominant class of records covered by our request seeking records: Gina McCarthy discussing her biggest assignment, the Obama administration's 'war on coal.'"

McCarthy has been nominated to succeed Lisa Jackson as EPA administrator and faces what is likely to be a tough Senate confirmation process, so the emails are sure to be a major issue during the coming hearings.

McCarthy is now EPA's assistant administrator for the Office of Air and Radiation, which plays a central role in the agency's coal regulatory program. She has been government payrolls throughout her 25-year career, according to her official EPA biography.

But in a statement to be released today, the Competitive Enterprise Institute said "those emails from her that are not withheld in full by EPA are typically redacted in full... For dozens of pages at a time, EPA withholds all the content of emails, claiming it need not reveal the contents because they were pre-decisional - discussions that are antecedent to the adoption of a formal agency policy, according the well-established law."

Exemption five of the FOIA allows but does not require federal agencies to withhold documents created as part of the deliberative process prior to a policy decision.

Earlier this week, the National Security Archive said use of Exemption Five by federal officials increased nearly 18 percent last year despite a 2009 directive from Attorney General Eric Holder that there be a "presumption in favor of disclosure."

The CEI statement claims that, to the contrary, "many clearly are not. They discuss press accounts of the agency's work, documents that tell then-administrator Lisa Jackson what questions to expect in interviews and similar conversations that EPA would rather fight than allow the public to see."

The emails posted on the EPA web site Friday are part of an estimated 12,000 internal agency emails ordered to be released to CEI by the U.S. District Court for the District of Columbia last year.

That order followed EPA's denial of CEI's Freedom of Information Act request for all internal agency emails concerning what the think tank described as President Obama's "war on coal."

Among the first batch of the emails, which were made public in January, were multiple emails to and from Jackson, who was using a fake name - Richard Windsor - on an EPA email account to conduct official business.

Transparency in government advocates argue that allowing the use of non de plumes in official email communications would allow documents to remain hidden in government digital archives that should be made public on request.

"Email from McCarthy discussing her biggest task continues to be the dog that doesn't bark," said Christopher Horner. "On this, we are to believe she had almost nothing to say. Possibly her contribution is found in her Oracle and IBM Sametime Instant Messages, which we also discovered EPA officials were using for sensitive discussions, a FOIA request for which EPA is completely stonewalling."

Horner is a CEI senior fellow, attorney and author of the book, The Liberal War on Transparency. While researching that for that book, Horner discovered evidence that EPA officials have been using non de plumes and private email accounts to conduct official business since the Clinton administration.

"The question is no longer whether they hiding things, it's what are they hiding now. And the answer apparently is: Whatever they have to hide to protect Ms. McCarthy's nomination," Horner said.

"You would think after having one administrator resign in disgrace over a false identity email account, the administration that claims to be the most transparent ever would move quickly to demonstrate something resembling openness on her appointed successor's records," Horner said. "But the administration has decided to do exactly the opposite, and go even further to keep from the public what its top environmental officials are doing."

For some examples of previous Examiner coverage of the Windsorgate scandal go here, here, here and here.