Four persons were killed following an explosion of a suspected hydrogen gas cylinder which was being used to inflate balloons at a rural fair in the South-24 Parganas district on Sunday night.

Four villagers have been critically injured in the blast at Batra village near Joynagar and are undergoing treatment at various hospitals. The blast has raised questions about the monitoring mechanism of the district administration.

While officials of the Bakultala police station did not bother to evict the balloon seller from the crowded fair in the absence of any administrative order, senior officials of the South 24-Parganas district administration claimed that there was “standing instruction” to police authorities across the district not to allow any stall or vendor at any fair that posed “potential threat” to human lives.

“Such dangerous items should not have been there at any fair. It is shocking how this was allowed. We need to check this,” South 24-Parganas district magistrate Sumit Gupta told The Telegraph.

“There is no written order so far in this regard, but police authorities have been clearly told not to allow any such item (at places of public gathering),” the DM added.

The balloon cyinder blast that occurred around 9.30pm on Sunday killed Kutubuddin Mistry, 38, Sahin Mollah, 12, and Abir Gazi, 8, on the spot, while gas balloon seller Muchiram Halder, 55, who lost one of his legs, succumbed to injuries later at a local hospital.

Officials of Bakultala police station and adjacent Joynagar police station rushed to the spot and controlled the situation clearing the ground.

Following a preliminary probe, police suspect that the cylinder containing helium gas was used to inflate balloons and it had exploded. But, local sources claimed that cheaper hydrogen gas was illegally used by the vendor to inflate balloons.

The police have started a case of unnatural death and ruled out any slackness on its part.

“It is hard to spot the kind of gas vendors use to sell balloons,” said an official of Bakultala police station.

A senior official of the state fire service department said inflating balloons using hydrogen gas required fire safety permission, which is not granted for several years in the wake of the high risk and recent accidents.

“But it is the duty of the local police to ensure no such vendor used hydrogen gas cylinders to inflate balloons,” the official said.

Superintendent of police, Baruipur police district, Pushpa, however, said, “Regulation about restrictions on such vendors is generally looked after by the civil administration.”

Fire service officials said there was a lack of awareness among the police and common people about the dangers of using hydrogen to inflate balloons.

“According to the international fire safety code, inflation of balloons using hydrogen gas is prohibited. Even our neighbouring country Bangladesh has also banned it. But, we have no such prohibition yet,” a fire official said.

A gas balloon vendor, who refused to be identified, said caustic soda and aluminium powder were used as reactors to produce hydrogen gas as an alternative to helium gas, which is very expensive.

“A cubic metre of hydrogen costs Rs 800, while the same amount of helium costs Rs 2,700. If we use helium, there will be no buyer of gas balloons at rural fairs,” he said.