"Now that we have the climate deniers and the oil industry taking over the reigns of the government, California's ability to assert itself becomes a lot more important," Huffman said in an interview on Monday.
"Exxon and other fossil fuel companies are part of the wealthiest, most powerful industry in the history of civilization. They have had enormous influence over the last several decades," Huffman said. "We need to get to the bottom of what they knew, when they knew it and what they did with that information when it comes to climate change."
"We can't comment on potential investigations to protect the integrity of any investigation," said Brenda Gonzalez, a spokeswoman for Becerra.
The Harris probe, revealed earlier last year, was aimed at finding out if ExxonMobil internally acknowledged the science behind climate change, but covered up studies and misled the public about the risks from global warming.
ExxonMobil disputes those claims.
"We reject allegations that ExxonMobil suppressed climate change research," said Scott Silvestri, a spokesman for the company.
"This is an inaccurate distortion of ExxonMobil's nearly 40-year history of climate research that was conducted publicly in conjunction with the Department of Energy, academics and the UN Intergovernmental Panel on Climate Change," Silvestri said in an email Monday.
"To suggest that we had reached definitive conclusions, decades before the world's experts and while climate science was in an early stage of development, is not credible," Silvestri said.
Harris' probe revealed by the Los Angeles Times, which took place amid similar investigations from prosecutors in New York and Massachusetts, gained support from California House Democrats in June after House Republicans announced a probe of their own into her investigation. Harris' office did not reveal details of a state investigation.
Rep. Lamar Smith (R-Texas), the chairman of the House Committee on Science, Space, and Technology, wrote Harris in May that his panel was concerned her investigation would "silence speech" and was "based on political theater rather than legal or scientific arguments."
"Your office -- funded with taxpayer dollars -- is using legal actions and investigative tactics in close coordination with certain special interest groups and trial attorneys that may rise to the level of an abuse of prosecutorial discretion," Smith wrote in his letter to Harris. "Further, such actions call into question the integrity of your office."
A representative of the committee did not respond to requests for comment.
The new push comes a week after Rex Tillerson, the former CEO of ExxonMobil, was confirmed as the nation's secretary of state, a fact not lost on local environmentalists.
"California's attorney general is our first line of defense against President Trump and his corporate allies," said Hollin Kretzmann, an Oakland-based staff attorney at the Center for Biological Diversity's Climate Law Institute.
"Since the Trump administration and Exxon have become closely linked, we hope our new attorney general will investigate Exxon's well-documented assault on our climate," Kretzmann said. "It's increasingly clear that Exxon ignored its own scientists and misled the public about the fossil fuel industry's central role in climate change."
