Two persons died and three others injured after inhaling poisonous gas inside a septic tank at Naria upazila in Shariatpur. One of the deceased was a college student when he was working inside it at Pachok village under Vojeshwar union of the upazila on Friday. The deceased were identified as Tareq Khan, 19, son of Liton Khan, and Shahadat, son of Shah Alam Gorapir, of the same area. Officer-in-Charge (OC) Naria police station Manjurul Haque Akanda confirmed the matter.