Three former makers of lead paint created a public nuisance that continues to poison children, a jury decided Wednesday in the state's landmark lawsuit against the companies.

The verdict means the companies that once made lead paint and pigment could be held responsible for millions of dollars in cleanup and mitigation costs, though the state never put a dollar value on its lawsuit.

Superior Court Judge Michael Silverstein will decide later how much, if anything, the companies must pay.

The state argued that lead paint created a sweeping public nuisance that has poisoned tens of thousands of children since the early 1990s and contaminated hundreds of thousands of homes.

The sale of lead paint was banned in the United States in 1978 after studies showed it can cause serious health problems in children. But in Rhode Island, which has an old housing stock, lead paint still exists in many homes.

In 1999, Rhode Island became the first state to sue the lead paint industry.

The first trial ended in 2002 with a hung jury. The jury in the latest trial began deliberating Feb. 13 following more than three months of trial.

Jurors Wednesday found one of the four companies named in the suit, Atlantic Richfield Co., was not responsible. But it they found the three others were: Sherwin-Williams Co., NL Industries Inc. and Millennium Holdings.

Shares of Sherwin Williams fell $6.57, or 12 percent, to $46 in midday trading on the New York Stock Exchange. Shares of NL Industries fell 71 cents, or 4.9 percent, to $13.65.

The companies rested without calling any of their own witnesses, and their lawyers said during closing arguments that the state had failed to prove its case.

The state brought in doctors, who described how low levels of lead can be dangerous to a child and how lead-poisoned children can suffer behavioral disorders, gastrointestinal pain, brain damage and even death.

It's attorneys argued that the companies or their corporate predecessors continued to manufacture lead pigment for use in paint even when they its potential dangers.

The companies said lead paint remained a problem in only a narrow subsection of poorly maintained properties. They also said paint is not the only source of lead exposure and argued that the state did not prove a clear link between the lead pigment they made and children who were poisoned by lead in Rhode Island.

Jurors were asked to decide whether the presence of paint creates a public nuisance and, if so, whether the companies significantly contributed to the nuisance and should be required to help fix the problem.

The state wants the companies to pay for a program that would include home inspections, lead paint removal or abatement and public education. It did not estimate a cost.

Last June, the state agreed to drop DuPont Co. from the lawsuit after the company said it would pay several million dollars to the nonprofit group Children's Health Forum for lead paint remediation, public education, and compliance programs in Rhode Island.