A federal judge has dismissed four of seven claims in a lawsuit filed by more than 70 Tiverton residents against Southern Union Co., the owner of a Fall River gas company that allegedly dumped contaminated fill material in their neighborhood more than 50 years ago.

In a 29-page decision issued Friday, Judge Ernest C. Torres said that the Tiverton residents who filed the suit may be able to prove three of the counts, but not four others. The counts he dismissed were those accusing Southern Union of gross negligence, creating a private nuisance, infliction of emotional distress and violating the Rhode Island Hazardous Waste Management Act.

The remaining counts allege negligence, that Southern Union is liable because it mishandled a hazardous substance and that the company created a public nuisance. Torres also said that those who filed the suit could seek punitive damages if they can show evidence that Southern Union’s actions were based on “malice, recklessness or wickedness.”

The lawsuit alleges that Southern Union is responsible for the contamination of more than 50 acres of public and private property in Tiverton. State officials have concluded that the contaminants are hazardous and that they came from a nearby gas plant owned by a Southern Union subsidiary.

Both sides in the case said they viewed the decision as positive.

Southern Union said in a news release that it was “gratified” that four of the counts were dismissed. “The company believes that the remaining claims also lack merit, and it will continue its vigorous defense of those claims,” said Eric D. Herschmann, senior executive vice president of Houston-based Southern Union.

Gail Corvello, the lead plaintiff, said she was glad the judge found merit in the suit and that the case can finally move forward. “We’re pleased with it,” Corvello said in a telephone interview. “I think that it was a long time coming.”

The decision came in response to a motion by Southern Union, filed in November 2005, to dismiss all seven counts.

The judge did not indicate how he might eventually rule. Torres said his decision to allow some claims and disallow others was based on standards that generally favor those who bring a suit, as long as the claims are not simply “bald assertions.”

Claims can be dismissed, Torres wrote, “only if it appears that the plaintiffs cannot prove any set of facts entitling them to relief.”

“At this juncture, the relevant facts are unknown,” Torres wrote. “There is no evidence regarding … what substances were deposited on or near the plaintiffs’ property, what role [Southern Union] may have played in depositing them, exactly what dangers the substances pose, whether that danger was recognizable at the time of disposition and whether the danger could have been eliminated by the exercise of reasonable care.”

The lawsuit stems from the discovery in 2002 of some blue soil that was being piled along Bay Street in Tiverton as part of a sewer-main installation. The blue color is often a signal that the soil could be contaminated with waste products associated with a process once used by utility companies to turn coal into gas. Subsequent tests performed by the Department of Environmental Management confirmed that the substances contained “cyanide and other hazardous substances.”

An investigation led the DEM to conclude that the waste material was dumped decades ago from the nearby Fall River Gas plant that once converted coal into gas. Southern Union purchased Fall River Gas in 2000.

Initially, Southern Union cooperated with state officials, performing soil tests in the neighborhood. The company even set up a Web site to keep area residents informed of the progress in addressing the contamination ( http://www.baystreetproject.com/). But the company now denies any responsibility for the contamination.

In May 2005, Corvello and other Tiverton residents filed civil lawsuits against Southern Union in Superior Court. The suits were eventually combined and the suit was moved to U.S. District Court in Providence.

In September, the DEM served notice to Southern Union that it was in violation of previous DEM orders to move forward on cleaning up the contaminated soil, and imposed a fine of $1,000 a day, retroactive to January.

Southern Union has appealed that notice and the fine. A status conference is scheduled for Nov. 20, and a pre-hearing conference is tentatively scheduled for Feb. 15. A hearing officer for the DEM will consider the appeal.

While Corvello said she welcomed Judge Torres’ ruling, residents remain frustrated that the cleanup effort has been stalled since 2002.

She questioned why the state won’t come in and clean up the site, and determine liability later.

“The process is so backward,” she said. “We are being exposed to hazardous materials, yet we have to wait years and years for a court to determine who is responsible, and then force them to do something about it.”

“It’s time for someone to get the shovels in the ground here.”