On the night of December 2, 1984, a deadly gas leak at the Union Carbide pesticide plant in Bhopal, India led to what has been described as the world’s worst industrial disaster. In the immediate aftermath of the gas leak, thousands of people died and hundreds of thousands were injured from exposure to the toxic gas methyl isocyanate. But long after the international headlines and news reports dwindled to silence, long after Union Carbide paid a paltry settlement to survivors, long after the disaster faded from much of the world’s memory, the gas leak continues to haunt the residents of Bhopal. In this episode, we trace the path of methyl isocyanate from initial discovery to the night of the disaster and the years that followed. We then explore what about this gas makes it so very deadly before assessing how the contamination still present at the site is causing health problems for residents decades after the gas leak.