Lisa Jackson, President-elect Barack Obama's nominee to lead the Environmental Protection Agency, said Monday the agency's way of doing business "probably" needs to change, and that she wants it to play a key role in promoting clean energy and other administration priorities.

Jackson, who for nearly three years led New Jersey's Department of Environmental Protection and spent the early part of her career as an EPA engineer, praised the work done by rank-and-file staffers and said it is important for them to know their efforts are valued.

"EPA's mission has never changed. Its mode of doing business has changed over the years and probably needs to change again," Jackson said in a telephone interview from Chicago. "I'm optimistic that EPA will be part of the agenda not just on environmental matters."

Jackson is in line to take over an agency that critics say has become marginalized under the Bush Administration.

Jackson said EPA can still be effective.

"As an environmentalist, (there's) no better job to have at this time, right now, provided the agency is allowed to do what it's supposed to do," Jackson said.

Jackson, 46, said she hopes to assure EPA scientists and staff that they will have a voice in the agency's work.

"I know what it means to work on technical issues in a large agency and how important it will be for folks all the way up the chain, administrators, technical staff and attorneys alike, to know that their work will be valued," Jackson said.

Jackson, who must still be confirmed by the U.S. Senate, gave few specifics about her agenda.

But she said she expects EPA to "certainly play a large role" in Obama's clean energy plans, noting that the agency has authority to regulate greenhouse gases and has technical expertise on environmental health.

Jackson, who has been with at DEP since 2002, became Corzine's chief-of-staff at the start of this month.

Contact staff writer Jonathan Tamari at 609-989-9016 or jtamari@phillynews.com.