SAN JOSE -- Anticipating a cleanup cost estimated as high as $1.6 billion, local governments from across California made their final legal pitch Monday to hold the paint industry accountable for allegedly threatening children's health by spreading toxic lead paint through tens of thousands of homes.

The industry countered by accusing public officials of a misguided smear campaign against paint manufacturers, arguing that the public health threat from lead paint has been wiped away for years.

The competing portraits ended a trial that began in July in a 13-year-old legal battle over the paint industry's role in exposing residents across California to dangerous levels of lead paint. Lawyers for 10 cities and counties, many of them in the Bay Area, urged a Santa Clara County judge to find that the powerful paint industry caused a "public nuisance" by selling lead paint for decades before the government banned the metal in 1978.

"They didn't care ... as long as they were making profits, they would continue to promote and sell lead paint," said Joseph Cotchett, an attorney for Santa Clara County and other governments backing the lawsuit.

But lawyers for five companies targeted argued that paint manufacturers relied for decades on public health officials and other medical experts who did not consider lower levels of toxic material in lead paint to be a serious public health threat, stressing that it was not until the late 1970s -- more than 80 years after the product was popularized -- that it was taken off the market. To them, the lawsuit is laying blame with the hindsight of modern research.

"The problem of lead paint has been attacked for decades," said Donald Scott, attorney for NL Industries. "And they are doing their jobs."

Local governments sued the industry in 2000, alleging paint manufacturers indeed knew the dangers of lead paint from the late 1800s through the 1970s, yet continued to peddle it to consumers. Santa Clara, Alameda, Monterey, San Mateo and San Francisco counties are pushing the legal claims, as are the cities of Oakland, San Diego and Los Angeles.

Public officials say tens of thousands of homes, many of them in low income neighborhoods, are tainted by hazardous levels of lead paint just in the 10 areas covered by the court cases. The lawsuit is not seeking damages or arguing that particular families were harmed by lead paint, but instead is asking the judge to order the industry to either set aside money for cleanup or take on the task itself -- at an estimated cost of $600 million and $1.6 billion.

Superior Court Judge James Kleinberg, who is hearing the case without a jury, at various points during Monday's arguments pressed the industry on its position. At one point, questioning the industry's argument that it relied on certain American doctors and experts when there was other evidence of the threat as early as 1918, Kleinberg said: "I'm quite troubled by the idea that because American doctors say 'X, Y and Z' that that is the end of the inquiry."

But five different lawyers argued that the paint manufacturers did not have knowledge of the lead paint threat through a long period in their businesses.

"There is no evidence of that," said Allen Ruby, lawyer for ConAgra, whose predecessor inherited the Fuller paint company in the early 1960s. "There is none."

Local governments, however, argue there is strong evidence that the industry ignored the threat, and that it continues to expose children living in older homes to unsafe levels of lead in their blood, causing a range of maladies from learning disabilities to seizures.

"What we've shown," Cotchett told the judge, "is that there was substantial and unnecessary toxic poisoning of children."

California officials are hoping to have more success in their case than have similar legal assaults in other states, including Rhode Island, Ohio and Missouri, where the industry has won in the courts. Kleinberg has 90 days to issue a ruling in the California case.

Regardless of Kleinberg's findings, the outcome is likely to be appealed.

Howard Mintz covers legal affairs. Contact him at 408-286-0236 or follow him at Twitter.com/hmintz.