Lead has been used for thousands of years in substances ranging from pipes to makeup. Ancient Romans even added lead to their wine as a sweetener. But these varied uses have left a terrible legacy, because lead is extremely toxic. It interferes with brain development, reducing intelligence and causing shortened attention spans and antisocial behavior. It also increases blood pressure, disrupts kidney function, and damages the reproductive system.
In light of its dangers, lead has been prohibited in many substances in the United States, most notably paint (by 1978) and gasoline (by 1985). But a significant amount of lead persists in the environment from past uses. Before its ban in gasoline, for example, lead-laced automobile exhaust settled into the soil, where it remains in many places. And to this day, homes, schools, and public buildings throughout the Bay Area that were constructed before 1978 contain leaded paint, which can be exposed when newer paint chips or flakes. In addition, lead is still legally used in many products in the United States, including batteries, vinyl, stained glass, and bullets. And many imported products, such as pottery and folk remedies from Asia and Central America, and even some imported cosmetics, contain lead.
Lead is a threat to everyone, but children are most susceptible, because their bodies are still developing. In addition, small children are more often exposed to lead because they crawl on the floor and put objects in their mouths. As a result, they are more likely to ingest lead in the form of contaminated dust or paint chips. In the Bay Area, as in many regions, these are the main sources of lead exposure for children.
Reporting and Testing
Overall, reported cases of childhood lead poisoning in the Bay Area declined 40 percent from 1992 to 1999. The decrease is good news, but it may not paint an accurate picture of childhood lead poisoning in the Bay Area. Although the decline may reflect progress in getting lead out of the environment, conclusions are difficult to draw for two reasons: the measure used to quantify the problem (reported cases) has limitations, and so does the lead standard.
Relying on the current blood-screening process as a measure of the problem is inherently limited. Because the number of unreported cases is impossible to gauge, the scope of the problem is impossible to gauge. Most children are never tested for lead poisoning. For instance, fewer than one-quarter of children enrolled in MediCal, California's Medicaid program, have been tested. These children are a high-risk population, because many of them are from poor urban areas with housing stocks that tend to have lead problems.
Even when testing is conducted, it has severe limitations. California uses a lax standard for lead poisoning, tracking only those cases in which blood levels are either greater than 20 micrograms per deciliter in a single test, or greater than 15 micrograms in two tests. By contrast, the federal government's standard is twice as strict: it considers blood levels of 10 micrograms per deciliter to be cause for concern.
Matters are further complicated because different types of testing follow different rules. Many lead tests are done by private, rather than government, laboratories. In California, private labs are not required to report blood lead levels under 25 micrograms per deciliter -- two-and-a-half times higher than the federal government's level of concern. (In general, tests done at public hospitals or clinics are processed at government labs; those done at private hospitals or doctors' offices go to private labs.) As a result, many children with lead poisoning under the federal definition do not even show up in the state's records.
All that said, Bay Area residents benefit from a California law that has helped get lead out of the environment. Although the state's standard for lead poisoning remains loose, Proposition 65 (the Safe Drinking Water and Toxic Enforcement Act) has given citizens the tools to fight for the removal of lead from varied sources. Proposition 65 lawsuits have already helped remove lead from calcium supplements, vinyl toys, water faucets, water meters, dishes, pottery, and hair dyes.