Additional commissioner (DB) of DMP Harun-Ur-Rashid said, "As per data available, Queen's sanitary market's basement is the origin of the explosion. Had the basement been spacious enough as per Rajuks's rules , it would have been easier to fix any problem immediately."

But the building owners once used the basement as a kitchen and then built an air conditioned construction materials' market without removing the kitchen's gas line properly, leaving the workers' and customers' lives at risk, the DMP official added.

Earlier, the massive explosion near a BRTC bus counter in the capital's Gulistan area has so far left 21 people dead.

A four-member probe body headed by lt col Mohammad Tajul Islam Chowdhury, director of fire service and civil defense (operation and maintenance), has been formed to investigate the explosion.

The committee was asked to submit its report within five working days, said Shahjahan Sikder, deputy additional director of Fire service and Civil Defense headquarters media cell.