Dhaka, May 20 -- A construction site in Brahmanbaria's Sarail Upazila has turned into a scene of disaster after four teenage labourers died following their entry into a septic tank.

The incident occurred around 4:15pm on Wednesday in Golania village, said Sarail Fire Service and Civil Defence officer Riaz Mohammad.

The dead were identified as Imam Hossain, 15, Hridoy Mia, 15, Arman, 14, and Mamsar, 18 -- the last two identified by single names.

Riaz said Fire Service personnel went down and found them dead.

"Rescue work is ongoing. It is suspected that gas built up inside the septic tank caused the incident, but nothing can be confirmed without investigation," said Riaz.

Around 6:30pm, Sarail Police chief Manjur Kader said police had...