> In 1865, (toxic) synthetic indigo dyes were created using petrochemicals by German Adolf von Baeyer, and this made cultivating indigo less profitable, so the

> In 1865, (toxic) synthetic indigo dyes were created using petrochemicals by German Adolf von Baeyer, and this made cultivating indigo less profitable, so the industry declined significantly. According to Wikipedia, synthetic indigo is the same as natural indigo, so not especially toxic. The products used in its synthesis (which include formaldehyde and cyanide) are toxic however.