Before the industrial revolution, the primary way to refine gold from diffuse ore was to dissolve the gold in mercury, separate the amalgam, and then boil out t

Before the industrial revolution, the primary way to refine gold from diffuse ore was to dissolve the gold in mercury, separate the amalgam, and then boil out the mercury to leave the gold behind. In large-scale mining, this resulted in local air pollution levels that were horrifying even when compared to the worst unmitigated industrial revolution era sites. Entire communities would get mercury poisoning from the air they breathed.