Gina McCarthy, President Obama's nominee to succeed Lisa Jackson as administrator of the Environmental Protection Agency, should be rejected for a variety of reasons, but one in particular stands out. McCarthy -- who has been EPA's assistant administrator for the office of air and radiation since 2009 -- too often operates behind closed doors in an agency with such immense regulatory powers that nothing less than maximum transparency is required to assure accountability.

A recent letter to McCarthy from Sens. David Vitter, R-La., and Jeff Sessions, R-Ala., points to an important example of McCarthy's penchant for making major decisions out of the public eye. Vitter, who is the ranking minority member of the Senate Environment and Public Works Committee, and Sessions, the ranking minority member of the subcommittee on clear air and nuclear safety, want answers on McCarthy's role in the EPA's "sue and settle" deal on its "Startup, Shutdown and Malfunction" exemption rule. Essentially, the 40-year old SSM exempts emissions sources such as power plants from emissions compliance immediately after startup and shutdown and during malfunction periods.

The Sierra Club unsuccessfully sought SSM repeal for years. But then in the 2011 settlement of an entirely separate litigation, the EPA unilaterally and without public comment agreed to repeal SSM. As Vitter and Sessions explain in their letter to McCarthy, "EPA went out of its way to resolve the SSM petition in a coordinated settlement with the Sierra Club ... These settlement agreements are often accomplished in a closed-door fashion that contravenes the executive branch's solemn obligation to defend the law, avoids transparency and accountability, excludes impacted parties, and often results in the federal government paying the legal bills of these special interest groups at taxpayer expense."

In other words, McCarthy actively participated in an action that "reaffirms a pattern and practice of circumventing transparency," according to the senators. There is another, more recent EPA action in which that pattern and practice is even more evident -- the "Richard Windsor" emails. Those are the approximately 12,000 official business emails sent to and from Jackson using Richard Windsor as her nom de plume. The fake name hid the emails from everybody -- including the EPA's own Freedom of Information Act compliance officials -- not in on the Richard Windsor secret.

McCarthy appears repeatedly in the nearly 6,000 Richard Windsor emails made public so far by EPA after a federal judge ordered their release to the Competitive Enterprise Institute last December. McCarthy should be challenged to explain why she participated in a tactic clearly designed to circumvent the Freedom of Information Act. The messages in the McCarthy emails -- most concerning the EPA's "cap-and-trade" approach to coal regulation -- are blacked out, according to CEI senior fellow Christopher Horner who first exposed the Windsor emails. Horner notes that McCarthy "was the chief lieutenant implementing it. Yet her thoughts on this matter are being withheld in full." Rejecting McCarthy's nomination would be a much-needed step toward holding Obama to his promise of "the most transparent administration in history."