Lead is among the most harmful chemicals in the environment. It is extremely toxic, posing multiple health dangers, especially to children. It is also among the best-understood harmful pollutants, and the accumulated knowledge about its danger is a powerful tool in the effort to reduce its health impact in the Bay Area. Indeed, by one measure -- reported cases of childhood lead poisoning -- the trends are in the right direction. The declining incidence of reported poisoning, however, may not accurately reflect the true extent of lead poisoning in the region.
NRDC researchers examined California data on lead poisoning in Bay Area children under age 16 between 1992 and 1999, and found that reported cases declined 40 percent for the period. But many children are never tested, and the state standard is very lax. As a result, childhood lead poisoning may remain a bigger problem than this apparently positive statistic suggests.
Under the California standard, lead poisoning is defined as one blood test showing lead at 20 micrograms per deciliter or greater, or two tests with results greater than 15 micrograms per deciliter.
According to the state data, during the period 1992 to 1999, Alameda County reported about 43 percent of all childhood lead poisonings in the Bay Area (599 cases), with Santa Clara and San Francisco coming in second and third (292 and 258, respectively). Marin (5 cases) and Napa (4) had the lowest totals for the period.