Despite being one of the earliest metals exploited by man, lead is an environmental poison. If it gets into the body it causes a variety of acute and chronic symptoms and even low levels are thought to have noticeable effects especially on children (see the wikipedia article on lead poisoning). Lead poisoning has even been proposed as a cause for the decline or the Roman Empire (who inter alia used lead acetate as a wine sweetener. See this site for some references).
But lead and many lead containing substances are fairly inert. Lead paint won't poison you because your house is painted with it unless you strip it using unsafe methods or your children eat it (which is the real hazard and the real reason it is now mostly prohibited). The large amounts of lead in CRTs is mostly there as an inert glass. Lead in electronic solder is not readily ingested.
But there are now worldwide bans on most uses of lead in the electronics industry. According to The book Scared To Death by Richard North and Christopher Booker (who seem to see themselves as debunkers of almost any modern environmental trend), the reason for the (very expensive and disruptive) ban was a dramatic overestimation of the amount of lead that would leach into the environment for landfill sites where electronics were dumped.
North and Booker are not the most unbiased or reliable sources for environmental facts. They criticise the original analysis (Townsend paper here as a pdf: a lab study of how fast lead in CRTs would leach into the environment) by quoting real world studies of landfill sites which fail to show the actual danger in the real world. A summary of some of this research says:
Hence, it is highly likely that actual landfill releases of these heavy metals are far lower than EPA estimates. These differences are far from minimal. As Townsend concludes: “For those state and local governmental agencies wrestling with whether to ban discarded electronics from landfills, the results of this work suggest that lead leaching from [computer circuit boards] and [TV and computer monitors] will be less than might be estimated using EPA’s TCLP results.” Even more importantly, concentrations from his landfill samples were comfortably below EPA’s standards of 5.0 mg/L. Yet it is important to note that these materials would not even enter the environment, since landfill operators collect and dispose of it in a safe manner.
So did we overreact to the presence of lead in electronics? Did the world bad lead because laboratory experiments dramatically overestimated the real-world impact of lead components in electrical waste? Do other studies show the ban was justified?