Lead poisoning has a far greater impact on global health than previously thought, potentially contributing to over five million deaths a year and posing a similar threat to air pollution.

Given the sharp decline in blood lead levels after the phase-out of leaded gasoline, lead exposure may seem to be a relic of the past. The reality is quite different, however. In a recent study by Bjorn Larsen and Ernesto Sánchez-Triana, the cost of lead exposure to the global population has been se...