WASHINGTON — Sen. David Vitter continued his criticism of the Environmental Protection Agency on Wednesday for its alleged lack of transparency regarding secretive or secondary email accounts by its leaders.

Vitter has particularly honed in on former EPA Administrator Lisa Jackson, of New Orleans, using the alias “Richard Windsor” as her secondary EPA email address with the allegation that she conducted some professional and personal business on the account. Vitter, of Louisiana, is the ranking Republican on the Senate Environment and Public Works Committee.

Vitter released new emails Wednesday he obtained that were sent to and from windsor.richard@epamail.epa.gov, in which Jackson corresponded with business executives and community and resource development activists.

The EPA has maintained administrators for decades have used secondary work email addresses to conduct some everyday business with EPA employees and government officials. But agency officials denied conducting outside business through the secondary emails.

“EPA has shown an absolute disregard for transparency with their email practices, but this one is pretty bizarre,” Vitter said in his announcement.

“We also know now that Lisa Jackson used the alias ‘Richard Windsor’ to correspond outside of the EPA, including with environmental activists,” Vitter continued. “There are still a lot of unanswered transparency questions, and Jackson’s replacement, nominee Gina McCarthy, is responsible for answering them and reinforcing transparency as a priority for the future of the Agency.”

Jackson stepped down in February after announcing she would not stay on for President Barack Obama’s second term. McCarthy, who is awaiting a Senate debate over her confirmation, currently heads the EPA’s air and radiation office.

In her committee confirmation hearing, McCarthy told Vitter she would be transparent and she does not use her personal email to conduct business.

The “Richard Windsor” emails released Wednesday showed Jackson communicating with a marketing firm executive who believed he was writing to the fictional Windsor, who he seemingly thought was Jackson’s assistant. The executive asked Windsor to pass on messages to Jackson and Jackson did not reveal that he was actually communicating directly with her.

The emails also showed Jackson using the “Windsor” account to communicate with people outside the government, including Cass Sunstein, who would later be chosen for a White House job.

Jackson also corresponded with a Ford Foundation community and resource development program official who now has an EPA job.