PROVIDENCE -- The state opened its historic lead paint lawsuit yesterday with a blistering attack against four corporations that it alleges continued to sell lead-based paints knowing they could poison children.

"This is a huge public problem," said lawyer Jack McConnell, who led off the state's opening arguments for the trial in a courtroom packed with child advocates, financial analysts and lawyers from around the country.

Some 250,000 homes in Rhode Island still have lead-based paints in or on them, McConnell said, earning Rhode Island the title "Lead Capital" of the country.

He said more than 35,000 children have been poisoned since the early 1990s. Last year alone, health officials reported that 7 children were poisoned so badly they had to be hospitalized, 172 children were "significantly" poisoned by lead and 1,160 were poisoned to a lesser extent.

"When I was little, my mom taught my five brothers and [me] that when you make a mess, you have to help clean it up." McConnell said. "That's how simple this case is."

McConnell, a lawyer for Motley Rice, led a legal team that said it will try to prove that lead paints have created a public nuisance, and convince the jury to demand that the companies spend millions of dollars to correct the problems they created.

The state expects the four accused corporations to repay it for the millions of dollars already spent on lead cleanups and treatment for children, to inspect every house with lead paint and to replace windows, doors and cabinets in those houses -- a job some say could cost billions of dollars.

The two companies that gave opening arguments yesterday accused the state of exaggerating the dangers and threatening to derail what amounts to a dramatic public health success story in the way Rhode Island has responded to the lead poisoning problem.

John Tarantino, a lawyer representing Atlantic Richfield, which owns what was once Anaconda Lead Smelting, said new cases of lead poisoning have declined by about 75 percent during the last two years in Rhode Island.

In 1993, 29 percent of young children in Rhode Island had elevated blood lead levels, Tarantino said. Today the figure is 2.7 percent.

The remaining problem is in 0.5 percent of all the homes containing lead, he said. Those houses have already been identified by the Health Department and that's where the remaining work needs to be done.

The vast majority of the homes are not the problem," Tarantino said. "This is not a massive public nuisance. It's a focused, targeted problem."

And it's a problem, he said, that has nearly been eliminated, according to data supplied by the Rhode Island Department of Health.

This is the second trial of the state's six-year-old nuisance complaint against the paint companies. The first ended in a hung jury.

The first trial was designed to establish one issue, whether the companies created a public nuisance with their paints. This trial is more ambitious. Its goal is to settle the nuisance issue, and then go on to establish liability and remedies.

With more evidence to be reviewed, the trial is expected to take from 10 weeks to four months. The opening arguments reflected the increased complexities.

Three lawyers spent the morning summing up the state's case. In the afternoon, Tarantino and Donald L. Scott summed up the defense for Atlantic Richfield and NL Industries.

This morning, lawyers for Millenium Holdings and Sherwin-Williams will make their opening arguments. The first witness is expected to take the stand tomorrow.

The trial has implications all over the country because dozens of individuals and communities have sued the companies for their production of lead paints. Other than a settlement won by one youth last week in Wisconsin, there have been no victories.

No other state has ever gotten this far with such a suit against the companies.

If Rhode Island prevails, analysts say, that could have a big impact on the four huge corporations because others would be encouraged to press suits. The private law firm helping Rhode Island present its case, Motley Rice, is representing clients in similar cases around the country.

If Rhode Island loses, that would have a chilling effect on more lawsuits.

The two sides gave jurors an overview of the arguments they will make, some of the witnesses they will call and much of the evidence they hope to present at trial.

The state said it will call Dr. Philip Landrigan, a pediatrician who is a "giant in his field"; Providence Mayor David N. Cicilline, who will talk about the impact of lead poisoning; June Tourangeau, a nurse at the St. Joseph Hospital lead clinic who will describe the difficulties of drawing blood from little children to screen them for lead; and Dr. Patricia Nolan, the former state health director, to describe the burden lead poisonings have put on the state.

The paint companies said they will call Dr. Peter Simon, a state Health Department physician who they said will testify that much of the low blood lead levels now found are medically acceptable.

The companies also plan to introduce experts who will testify that lead paints don't deteriorate when painted over and maintained.

Both sides held up 80-year-old industry advertisements and memos to prove their cases.

Scott insisted the state was trying to apply modern medical discoveries to a time when such knowledge wasn't available.

"The hazards today simply were not in existence 100 years ago, or 50 years ago or in 1978," said Scott. "Hindisght is not a substitute for history."