President Barack Obama has nominated Gina McCarthy as the head of the Environmental Protection Agency (EPA).

The nomination of McCarthy, who currently serves as assistant administrator of EPA’s air and radiation office, to replace Lisa Jackson is a likely sign that the administration will seek to further the use of the EPA as a regulatory arm to administer policies to lower greenhouse gas emissions if legislative efforts continue to fail in Congress.

“The president’s nomination of Gina McCarthy as head of EPA reinforces his agenda to take climate change action through the executive branch of government,” John Kneiss, Hart Energy’s Director of Government Affairs & U.S. Policy, tells Midstream Business.

In her current post, McCarthy has worked on some of the agency’s more controversial regulatory efforts, including reductions of mercury and soot discharged from power plants and boilers that could make her confirmation difficult. However, the administration expects that her past experience with Republican administrations on the state level will help her secure confirmation from Congress.

Kneiss said that McCarthy’s confirmation hearings will likely feature heavy scrutiny from Republicans, but ultimately her prior confirmation by Congress in her current post should see her be confirmed as head of EPA.

“The Senate confirmation is likely to occur, but it will be a challenge and she’ll be placed under considerable scrutiny by the Republicans. They’ve already confirmed her once, so she should ultimately be confirmed again for this post,” he said.

She previously served as the commissioner of the Connecticut Department of Environmental Protection as well as a special advisor on climate and environmental issues to multiple Massachusetts governors, including Mitt Romney. While serving under the Republican Romney administration, she helped the state deliver its Climate Protection Action Plan, which set goals for reducing greenhouse gas emissions in the state.

While serving Republican governor Jodi Rell in Connecticut in 2004, she worked on the Regional Greenhouse Gas Initiative, a carbon cap-and-trade system that includes Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New York, Rhode Island and Vermont.

“As assistant EPA administrator, Gina’s focused on practical, cost-effective ways to keep our air clean and our economy growing,” Obama said during a press conference to announce the nomination. “She’s earned a reputation as a straight-shooter. She welcomes different points of views. I’m confident that she’s going to do an outstanding job leading the EPA.”

Sen. Barbara Boxer, chairman of the Senate Environment and Public Works Committee, hailed the nomination in a statement. “The president could not have picked a more qualified person to lead EPA at this critical time. The combination of her experience, intelligence, energy and unquestioned expertise will make Gina an effective EPA administrator. She has a deep understanding that the health and safety of the American people depends on clean air and clean water. Gina is the right person for the job, and we will move forward with her confirmation hearing as quickly as possible.”

However, Sen. James Inhofe (Republican- Oklahoma) indicated that the confirmation could face some headwinds. “By nominating Gina McCarthy to replace Lisa Jackson, the president is making it clear that he wants to continue pursuing an aggressive climate agenda at EPA. As head of the Air office, McCarthy oversaw some of the agency’s most costly and controversial rules, like the Utility MACT. That said, as we approach her confirmation process in the Senate, I look forward to sitting down and talking with her to find common ground as I did with Lisa Jackson. As ranking member of the EPW Oversight Subcommittee, my priority is to ensure that EPA follows sound science and accurate cost-benefit analysis to ensure government’s encroachment into entrepreneurship and American ingenuity is instructed by facts, and not political gamesmanship. This will be among the key issues I aim to address with McCarthy and an area I hope we can reach agreement on.”