by sanding or torching, creates lead-containing dust and fumes, it is generally safer to seal the lead paint under new paint (excepting moveable windows and doors, which create paint dust when operated). Alternatively, special precautions must be taken if the lead paint is to be removed.In oil painting, it was once common for colours such as yellow or white to be made with lead carbonate. Lead white oil colour was the main white of oil painters until superseded by compounds containing zinc or titanium in the mid-20th century. It is speculated that the painter Caravaggio and possibly Francisco Goya and Vincent Van Gogh had lead poisoning due to overexposure or carelessness when handling this colour. Soil
Residual lead in soil contributes to lead exposure in urban areas. It has been thought that the more polluted an area is with various contaminants, the more likely it is to contain lead. However, this is not always the case, as there are several other reasons for lead contamination in soil.Lead content in soil may be caused by broken-down lead paint, residues from lead-containing gasoline, used engine oil, tire weights, or pesticides used in the past, contaminated landfills, or from nearby industries such as foundries or smelters. For example, in the Montevideo neighborhood of La Teja, former industrial sites became important sources of exposure in local communities in the early 2000s.
|bot=InternetArchiveBot |fix-attempted=yes }}</ref> It was not until the second half of the 20th century that subclinical lead exposure became understood to be a problem. During the end of the 20th century, the blood lead levels deemed acceptable steadily declined. Blood lead levels once considered safe are now considered hazardous, with no known safe threshold.In the late 1950s through the 1970s Herbert Needleman and Clair Cameron Patterson did research trying to prove leads toxicity to humans. In the 1980s Needleman was falsely accused of scientific misconduct by the lead industry associates.In 2002 Tommy Thompson, secretary of Health and Human Services appointed at least two persons with conflicts of interest to the CDCs Lead Advisory Committee. In 2014 a case by the state of California against a number of companies decided against Sherwin-Williams, NL Industries and ConAgra and ordered them to pay $1.15 billion. The disposition of The People v. ConAgra Grocery Products Company et al. in the California 6th Appellate District Court on 14 November 2017 is that:... the judgment is reversed, and the matter is remanded to the trial court with directions to (1) recalculate the amount of the abatement fund to limit it to the amount necessary to cover the cost of remediating pre-1951 homes, and (2) hold an evidentiary hearing regarding the appointment of a suitable receiver. The Plaintiff shall recover its costs on appeal.