The ruling means that if Attorney General Sheldon Whitehouse is able to prove that lead-paint and pigment manufacturers did cause a public nuisance, the case could proceed to hearings on whether the industry is to blame and what type of remedy is warranted.

The Rhode Island case is perhaps the most important such legal challenge to the companies named in a growing number of lead-paint lawsuits around the country. Defendants include The Sherwin-Williams Co., the Glidden Co. unit of ICI, and several former suppliers of lead-based pigments.

A group called the Alliance to End Childhood Lead Poisoning called Silverstein's ruling a "huge win" for the state, saying the decision will allow the case to proceed to trial by later this year. But an adviser to the defendants, former Maine Attorney General Andrew Ketterer, said he was confident the companies would be able to prove they are not responsible for such a nuisance.

The companies contend that lead paint is safe as long as it is intact and not flaking or peeling. Once it deteriorates, the companies say, it's up to landlords to make repairs to ensure safety of their properties.

"It is easy for the state to create the appearance of action by announcing a high-profile lawsuit," Ketterer was quoted as saying in an Associated Press report. "But if the goal is protecting children, Rhode Island should focus its attention on the few bad landlords who have failed to maintain their properties and are creating an unacceptable risk for children."

Thomas Graves, vice president and general counsel of the National Paint & Coatings Association, said the ruling actually places a "heavy burden" on the state of Rhode Island to prove "that selling or marketing a legal product...constitutes a public nuisance." Graves also noted that Silverstein last year dismissed the product-liability claims in the Rhode Island suit, narrowing the scope of the suit.

Whitehouse, meanwhile, applauded Silverstein's ruling, saying it would allow the state to focus on a single issue and move forward more quickly with the lawsuit. "The more we narrow the issue, the less opportunity there is for the defendants to muddy the waters and create delays," he said.

Graves said a ruling finding that lead-based paint poses a public nuisance would require the court to "break with virtually all relevant legal precedent" and determine "that a manufacturer of a legal product is absolutely accountable for its proper maintenance in perpetuity, regardless of intervening causes or others' duties under the law, against sound legal reasoning and judicial notions of fairness and equity.

"The judge appears to be allowing his state's attorney general a very big roll of the dice, which based on legal precedent, logic and fundamental fairness, ought to come up craps, actually speeding the case to an expedited conclusion," Graves said.