More than 40 tons of methyl isocyanate spilled from a Union Carbide-owned pesticide factory in Bhopal, India, in 1984, killing more than 20,000 people in the world's worst chemical disaster. After the spill, these skulls were researched, presumably for the specific effects the gas had on the brain, at the nearby Hamidia Hospital. The chemical injured not only the people who inhaled it, but also nearby animals (at least 2,000 of them) and trees, whose leaves went yellow and fell off within days.

Twenty-five years later, with people still claiming injury from the disaster yet little corrective action having been taken, the government of India has called for a study into the long-term effects of the spill.