Title: Lead, mortality, and productivity
Description: "This paper examines the effect of water-borne lead exposure on infant mortality in American cities over the period 1900-1920.  Infants are highly sensitive to lead, and more broadly are a marker for current environmental conditions.  The effects of lead on infant mortality are identified by variation across cities in water acidity and the types of service pipes - lead, iron, or concrete - which together determined the extent of lead exposure.  Time series estimates and estimates that restrict the sample to cities with lead pipes provide further support for the causal link between water-borne lead and infant mortality.  The magnitudes of the effects were large.  In 1900, a decline in exposure equivalent to an increase in pH from 6.7 to 7.5 in cities with lead-only pipes would have been associated with a decrease in infant mortality of 12.3 to 14.3 percent or about 22 fewer infant deaths per 1,000 live births.  City-level evidence on wages in manufacturing suggests that the adverse health effects of lead may have extended beyond infants"--National Bureau of Economic Research web site.