Saroj Bhattacharjee, 81, calls it the “biggest trauma” of his life. The Edmonton man was a maintenance engineer at Union Carbide in Bhopal, India, in 1984, when the toxic gas methyl isocyanate leaked from a storage tank.

Nathuram Soni vividly remembers the night 40 years ago when toxic gas swept through Bhopal killing more than 3,500 people in the shanties surrounding the Union Carbide pesticides plant.

Even after 40 years, neither Union Carbide nor its employees have faced any real consequences for their role in the disaster. Survivors and families of the dead are still fighting for proper compensation. Worse, the toxic effects of the gas continue to poison successive generations.

Considered the world’s worst industrial incident in modern times, the Bhopal gas tragedy was a chemical accident at a pesticide plant in Bhopal, Madhya Pradesh, India.

Forty years after the Bhopal disaster on December 2-3, 1984, several hundred tonnes of toxic waste still remain around the ill-fated Union Carbide plant. Despite pleas from locals and activists — bolstered over the years by orders from the National Green Tribunal and the Supreme Court — to dispose of the waste,