The incident occurred when Ravindra Solanki (42) and Narendra Patel (40) were cleaning the tank at the under-construction factory in the morning, they said, adding the duo were hired by the factory management for the work.
"We believe that due to toxic fumes in the empty storage tank, both of them died of suffocation. After they fell unconscious, both of them were rushed to a nearby hospital by other staff. However, the doctors declared them brought dead," said police sub-inspector of Dholka town H G Solanki.