Not gone with the wind: Long-run impact of herbicidal warfare in Vietnam

We investigate the legacies of herbicidal warfare on population size and growth in Vietnam between 2001 and 2020. The identification strategy exploits flight-level military records and plausibly exogenous hamlet-level variation around the spray-on, direction-change, and spray-off points of fixed-wing aircraft missions, combined with a fuzzy regression kink design. The elasticity estimate suggests that a 10% increase in predicted herbicide exposure during the Vietnam War is persistently associated with a decrease in population size, ranging from 1.88–2.51% in 2001 to 2.61–3.27% in 2020. We also find that a 10% increase in predicted herbicide exposure is associated with a 0.75 percentage-point decrease in the population growth rate over the 2001–2020 period. These findings reveal previously unseen, lasting legacies of herbicidal warfare on contemporary population outcomes. The empirical patterns run counter to the conventional wisdom of a rapid recovery or a catch-up growth in post-war societies after destruction, while also contributing to the emerging debate over the socioeconomic and public health consequences of broader chemical exposure.