Opinion ID: 1787304
Heading Depth: 2
Heading Rank: 2

Heading: Lead Paint and White Lead Carbonate Pigment.

Text: ¶ 36. Paint is comprised of two major components: the pigment, which provides hiding power and protects the surface, and the vehicle, which allows the pigment to be spread and adhered to a surface. In the first part of the 20th century, there were many different types of pigment, lead and non-lead based. [13] Generally, paint manufacturers decided what pigments and amounts of pigments to use when formulating their paints. Many of the Pigment Manufacturers also produced ready-mixed lead-based paint. ¶ 37. The predominant lead pigment that was manufactured and integrated into paint was white lead carbonate. White lead carbonate was the first chemical produced commercially in this country. That pigment was initially favored because when used alone it was the most durable and easy to apply. It was also believed to be a mildewcide. [14] All of the Pigment Manufacturers, or their predecessors-in-interests, produced this pigment at varying times since the houses in which Thomas resided were constructed in 1900 and 1905. ¶ 38. White lead carbonate could be comprised of any of three different chemical compounds. Basic lead carbonate had two chemical compositions, 4PbCO32Pb(OH)2PbO and 2PbCO3Pb(OH)2. Free normal lead carbonate's chemical composition was PbCO3. Basic lead carbonate was the overwhelming form of lead pigment used in paint. ¶ 39. In addition to having different chemical compositions, the physical properties of white lead carbonate varied. These variances included different specific gravity, [15] bulking values, oil absorption, hiding power, and particle size and shape. [16] Pigment Manufacturers also distinguished between grades of lead carbonate and apparently promoted each for different purposes. ¶ 40. Thomas's toxicologist expert, Mushak, opines that the toxicological effects of white lead carbonate remain the same notwithstanding the formulary differences between the white lead carbonate pigments. Mushak states that there is little relationship between chemical diversity and the bioavailability of the lead, which refers to the lead uptake or lead absorption into the human body. Mushak explains that [t]he reasons why one cannot automatically equate differences in chemical composition with differences in bioavailability is because bioavailability operates via a set of biological, biochemical and physico-chemical processes that will often render starting forms of lead in pigments indistinguishable in toxicokinetic terms. [17] Based on observational evidence (which Mushak characterizes as the huge body of toxicological literature showing that lead paint poisoning is pervasive and rather uniformly intense as to the severity of exposures) and laboratory evidence, Mushak concludes that there is no basis to conclude that formulary changes among white lead carbonates affect the bioavailability of the lead.