Light cigarettes can deliver a higher level of toxicity than their regular counterparts, according to a former director of research at Phillip Morris. That allegation is at the center of a legal battle between tobacco companies and light cigarette smokers, who scored a major legal victory today when tens of millions of light cigarette smokers were granted class action status in a lawsuit that could cost tobacco companies hundreds of billions of dollars. The lawsuit centers around the allegation that tobacco companies have fraudulently marketed light cigarettes as a safer alternative to regular cigarettes, when the companies knew that wasn’t the case. A former director of applied research for Phillip Morris told ABC News that light cigarettes can actually be more toxic to smokers than regulars. They are a "very nasty trick" according to Bill Farone, the former director of research at Phillip Morris. "If you’re used to smoking a Marlboro regular and you switch to a light, what you end up doing is simply sucking a little harder," said Farone. "You end up getting about the same amount of tar, the same amount of nicotine." Farone added that because of the chemical changes that occur during the burning of the cigarette, a light cigarette can actually deliver higher levels of many other cancer-causing materials. "That’s been documented and you can see it in some of the chemistry," he said. Farone also says that Phillip Morris has known all along that light cigarettes are not a safer alternative to regulars. "There’s no doubt that Phillip Morris knew the properties of its products then and does now." Phillip Morris and other tobacco companies say they plan to appeal today’s ruling by U.S. District Judge Jack Weinstein. The lawsuit, which was filed in 2004, differs from other tobacco litigation in that the plaintiffs are not seeking damages for health problems, but instead claim that they’ve been defrauded by the tobacco companies. "This case involved smokers who are not seeking to recover for personal injuries, who continue to smoke ‘light’ cigarettes and who paid no more for Marlboro Lights cigarettes than they would have paid for regular Marlboros," said William S. Ohlemeyer, Phillip Morris’s associate general counsel. On their website, Phillip Morris acknowledges that some researchers have found smokers inhale just as much tar and nicotine from light cigarettes as they do from regulars. They also add: "The amount of tar and nicotine inhaled will be higher if, for example, a smoker blocks ventilation holes, inhales more deeply, takes more puffs or smokes more cigarettes." The company also says, however, that they do not claim that light cigarettes are a safer alternative. "PM USA does not imply in our marketing, and smokers should not assume, that lower-yielding brands are safe or safer than full-flavor brands. There is no safe cigarette," says the website. Tobacco prevention advocates, however, say that the tobacco industry knows that most smokers believe light cigarettes to be safer than regulars. "Light cigarettes are probably the most serious public health fraud that has ever been perpetrated on the American public," said Matthew Myers, President of the Campaign for Tobacco-Free Kids. Myers blames the lack of government regulation of the tobacco industry for allowing cigarette makers to advertise and promote their light cigarettes as ‘lights’ even though they can be just as dangerous as the regulars. "The tobacco industry’s products and claims are fundamentally unregulated," he said, "and the industry has successfully resisted regulation for 40 years."