<P> The traditional method making the pigment was called the stack process . Hundreds or thousands of earthenware pots containing vinegar and lead were embedded in a layer of either tan bark or cow feces . The pots were designed so that the vinegar and lead were in separate compartments, but the lead was in contact with the vapor of the vinegar . The lead was usually coiled into a spiral, and placed on a ledge inside the pot . The pot was loosely covered with a grid of lead, which allowed the carbon dioxide formed by the fermentation of the tan bark or the dung to circulate in the pot . Each layer of pots was covered by a new layer of tan, then another layer of pots . the heat created by the fermentation, acetic acid vapor and carbon dioxide within the stack did their work, and within a month the lead coils were covered with a crust of white lead . This crust was separated from the lead, washed and ground for pigment . This was an extremely dangerous process for the workmen . Medieval texts warned of the danger of "apoplexy, epilepsy, and paralysis" from working with lead white . </P> <P> Despite the risks, the pigment was very popular with artists because of its density and opacity; a small amount could cover a large surface . It was widely used by artists until the 19th century, when it was replaced by zinc white and titanium white . </P> <P> The dangers of lead paint were considered well - established by the beginning of the 20th century . In the July 1904 edition of its monthly publication, Sherwin - Williams reported the dangers of paint containing lead, noting that a French expert had deemed lead paint "poisonous in a large degree, both for the workmen and for the inhabitants of a house painted with lead colors ." As early as 1886, German health laws prohibited women and children from working in factories processing lead paint and lead sugar . </P> <P> Lead paint is hazardous . It can cause nervous system damage, stunted growth, kidney damage, and delayed development . It is dangerous to children because it tastes sweet, therefore encouraging children to put lead chips and toys with lead dust in their mouths . Lead paint is dangerous to adults and can cause reproductive problems in men or women . Decreases in sperm production in men have been noted . Lead is considered a possible and likely carcinogen . High levels may result in death . </P>

When did they stop using lead in auto paint