Gina McCarthy, President Obama’s nominee to head the Environmental Protection Agency, Thursday pledged a “common-sense” approach to battling climate change and touted a career that included working for five Republican governors in an effort to counter GOP criticism of the agency she hopes to lead.

McCarthy called fighting climate change “one of the greatest challenges of our generation and our great obligation to future generations. I am convinced that those steps can and must be pursued with common sense.” Along with public health benefits, she said, those efforts can “create markets for emerging and new technologies and new jobs.”

The hearing before the Senate Environment and Public Works committee broke down along party lines. Republican senators accused the EPA of killing jobs with overly burdensome air and water regulations and of failing to produce information they have sought on the basis for decisions on a variety of subjects.

Democrats characterized EPA decisions as based on sound science, emphasized the health benefits that cleaner air and water have produced in the 43 years since the EPA was created, and highlighted the economic benefits of environmental protections.

“The cost-benefit ratios of these laws are well documented,” said Sen. Benjamin L. Cardin (D-Md.).

Many people following McCarthy’s nomination say they think that she does not face major obstacles to confirmation. Republican Sen. Jeff Sessions of Alabama acknowledged at the hearing that it appeared McCarthy would be confirmed.

Currently the EPA’s assistant administrator in charge of air and radiation, McCarthy, 58, enjoys widespread support from environmentalists and respect from officials of some industries her agency regulates. Some have described her as a plain-spoken official who relies on data and is willing to hear their side. During a lengthy tenure in state government in Massachusetts and Connecticut, McCarthy worked for five Republican governors, including Mitt Romney.

If confirmed, McCarthy would lead an agency facing a number of important regulatory decisions. They include regulating carbon dioxide from existing power plants, cracking down on methane leaks from the search for and transport of natural gas and enacting tighter national smog standards.

Sen. David Vitter (R-La.) hammered the EPA, accusing the agency of a lack of transparency. “I’m concerned, as you know, that the central functions of the agency have been obfuscated by ideology” and “undermined by non-peer-reviewed science that the agency often keeps hidden,” he said.

The EPA and McCarthy’s office in particular suppress “the real economic harm of the rules put forward during the last four yearsthrough “a complex process of circumventing FOIA requests and congressional inquiries, conducting official business using alias and private e-mail accounts, hiding and cherry-picking scientific data, negotiating backroom deals and the manipulation of cost-benefit numbers,” Vitter asserted. FOIA refers to the Freedom of Information Act.

Under its previous administrator, Lisa P. Jackson, the EPA often attracted the criticism of manufacturing and utility executives, who accused it of imposing job-killing regulations.