The incident took place on Monday evening at Tata Electronics Private Limited's facility near Uddanapalli in Krishnagiri district. The workers were reportedly cleaning a nano-filtration feed tank at the plant's Effluent Treatment Plant (ETP). Three contract workers died of suspected asphyxiation while carrying out cleaning and maintenance work at a Tata Electronics facility manufacturing components for Apple iPhones in Tamil Nadu, according to reports by Reuters The incident took place on Monday.