Massachusetts Attorney General Maura Healey wants gas station owners to post warnings at the pump that say customers are spurring climate change by filling up their tanks.

The idea came up in oral arguments in Massachusetts Supreme Judicial Court Tuesday in a case challenging Exxon Mobil’s record on addressing the threat of global warming and the attorney general's claim that the company misinformed the public over the threat.

Justice Frank Gaziano asked how gas stations are involved in “deception or fraud related to climate change.”

“Because, your honor, the gas sold at those gas stations is among the premier contributors to global warming," Healey's lawyer, Richard Johnston, responded.

Healey has asked for information from Exxon related to the marketing of fossil fuels in Massachusetts, "including advertisements, in particular," Johnston said.

"So, I own Joe's gas station on the corner, I'm a franchisee, and you're telling me that I have information that relates to how Exxon Mobil, this gi-normous corporation, has marketed and lied on climate change?" Gaziano asked.

“If they’re doing sales and marketing in Massachusetts, and they know things that they should be telling people – either consumers or investors – that would be relevant to the consumers or investors’ decisions, then they’ve gotta make that part of their advertising. They can’t simply go around and say, ‘We’re selling you this terrific product,’ and keep to themselves what they know about the possible impacts of those products on global warming," Johnston said.

“The franchisee has to put on its gas station, ‘You’re creating global warming by buying my gas?’” Justice J.J. Kafker asked.

Johnston explained that Exxon would have a national and local obligation to warn its customers about the harm caused by climate change when they fill up. Most climate scientists blame the emissions from burning fossil fuels such as gasoline for driving manmade climate change.

“So Exxon has an obligation — and all of this is assuming that what we think may have happened did happen, and there was an understanding about the impact on climate change — that Exxon would have a responsibility both at the national level and at the local level to implement information to the consumers so that they could understand when they purchase a tank of gas that this is gonna have an impact on global warming and maybe they should be thinking about buying a more fuel-efficient car, maybe they should be thinking about public transportation," the lawyer said.

The pro-fossil fuel group Energy In-Depth played up Johnston's statements in a blog and email sent out Thursday.

Healey is part of a group of Democratic attorneys general who have been trying to take Exxon to task over reports that it suppressed its own scientific data from the 1970s that showed climate change would harm its business.

Healey is attempting to establish that the 300 Exxon-branded service stations in her state give her jurisdiction to pursue Exxon over its past climate research. Healey and New York Attorney General Eric Schneiderman have pursued the company for nearly two years to obtain documents that they hope will show the company knew the threat to its business from climate change.

The hearing was meant to determine whether Exxon is legally obligated to respond to Healey's previous subpoenas requesting information based on stories published by the LA Times and Inside Climate News. Exxon argues that the 300 stations in the state are owned by the franchisee, not the company, even though the franchisee has to pay the company fees.

Exxon is engaged in multiple court fights to quash the Democratic state attorneys' arguments. It adamantly opposes the assertions that it suppressed information on climate change or misinformed investors.