A class-action lawsuit alleged that Eversource Energy violated Massachusetts consumer protection and false advertising laws by consistently marketing natural gas as "clean," "safe" and "good" for families and the environment.

The language and images used in Eversource marketing materials misled consumers by creating a false impression that gas use is safe, in contrast to research linking indoor gas combustion with negative health outcomes, according to a complaint filed May 31 in the Suffolk County Superior Court.

Additionally, the company's portrayal of gas as environmentally friendly concealed the planet-warming impact of methane leaks and dovetailed with a sustained campaign of greenwashing, the complaint said.

The lawsuit is the latest development in a yearslong debate over the potential health impacts of gas appliances, particularly cooktops and stoves.

Several appliance manufacturers are facing lawsuits over those alleged health impacts. But the Eversource complaint appeared to be the first time that a lawsuit has leveled charges of false advertising in an effort to force a gas utility to correct past statements and pay damages.

While the legal strategy is novel, the attorney who brought the case said it is firmly rooted in established law. "We think this is a pretty simple case that we should prevail on," Jason Adkins, an attorney for Adkins, Kelston and Zavitz PC, told S&P Global Commodity Insights.

Eversource "believes the claims in the lawsuit lack legal or factual merit" and plans to "defend the company's record vigorously," Eversource media relations manager William Hinkle said in an email.

Health arguments based on contentious research

The pillars of the lawsuit are a pair of Massachusetts General Laws that prohibit "untrue, deceptive or misleading" advertisements and govern business practices for consumer protection. The latter bars "unfair or deceptive acts" and directs state courts to follow US Federal Trade Commission (FTC) interpretations, including guidelines for environmental marketing claims.

Those guidelines say marketers "must ensure that all reasonable interpretations of their claims are truthful, not misleading and supported by a reasonable basis before they make the claims." To substantiate that the claims are true, marketers must present evidence "sufficient in quality and quantity based on standards generally accepted in the relevant scientific fields, when considered in light of the entire body of relevant and reliable scientific evidence."

Adkins and fellow attorneys pointed to a body of research that suggests burning gas indoors exposes residents to health-harming nitrogen oxides. They additionally cited more recent studies indicating the presence of carcinogens and other hazardous air pollutants in gas samples from stoves.

The gas industry has disputed some of those studies and the broader link between gas use and negative health outcomes.

But in light of the research, the attorneys said Eversource did not meet the burden required to market gas as "clean" and "healthy" under FTC guidelines. That marketing language — and images of parents and children gathered around cooktops — constituted impermissible implications that gas is nontoxic, the attorneys said.

Suit challenges environmental benefits

The attorneys also argued that Eversource's messaging about the environmental benefits of natural gas violated FTC guidelines, which say an "environmental marketing claim should not overstate, directly or by implication, an environmental attribute or benefit."

The attorneys argued that Eversource has not been forthright about the impact of fugitive methane, which has a greater short-term global warming impact than carbon dioxide. They said Eversource's system still has a lot of leak-prone pipe and pointed to research that suggests US methane emission inventories underestimated leaks from Boston-area gas infrastructure.

The complaint also alleged that Eversource omitted important information in its messaging about its sustainability goals and its target of net-zero emissions from operations by 2030, making the marketing "actionable greenwashing."

Hinkle said Eversource is working with stakeholders across Massachusetts to achieve the state's decarbonization goals, including by recently launching a networked geothermal pilot project. "Our customers' energy needs are diverse, and it's important that the clean energy transition provides access to safe, reliable and affordable energy for everyone," he said.

Complaint seeks remedies

The complaint sought to establish a class-action lawsuit with a pair of Eversource's Massachusetts customers representing all of Eversource's residential customers. The suit also asked the court to establish a subclass of consumers who use gas stoves and were allegedly exposed to toxic chemicals.

It could take two to three years before a judge determines whether a class-action suit can proceed, Adkins said. The suit sought damages on behalf of the class and subclass.

The complaint additionally asked the court to declare that Eversource's gas advertising contains false, misleading and deceptive statements. It asked the court to enjoin the company from making similar statements in the future to market gas use, appliances and conversions. Finally, it asked the court to order Eversource to make "reasonable and regular" disclosures correcting its prior statements.