A government that has been strict about shutting down tinderbox establishments and ordering the arrest of their owners on grounds of negligence was caught napping on Friday when a blaze in the New Secretariat exposed how unsafe some of its own buildings are.

The 13-storey landmark on Strand Road was still in snooze mode at 10.20am when a few of those who had arrived for work on time noticed the fire originating in a room on the seventh floor. Nobody heard a fire alarm ring, there were no sprinklers and hardly anyone with some training was around to evacuate people and prevent the flames from spreading.

When the fire brigade arrived with men and machines, the hydraulic ladder couldn't be manoeuvred to reach the affected floor for want of space. The building layout, which should have been on a wall or a board at a visible place, wasn't available to the firemen when they needed it.

"For the first 30 minutes, we tried dousing the fire from the terraces of adjacent buildings because our men couldn't figure out how to access the origin of the blaze without the building layout. They were reduced to aiming the hosepipes at the windows from which flames were leaping out," a senior official of the fire services department said.

For a building that had flouted every rule in the fire-safety manual, the New Secretariat was lucky to get away with a gutted floor and no casualties and injuries, sources said.

The fire brigade had deployed 25 fire tenders to fight the blaze within 10 minutes of receiving a call. "The firemen split into two groups, the first one going for the seventh floor and the second team accessing the rooftop of Block C," Sanjay Mukherjee, the director-general of fire services, told Metro.

Fire minister Javed Ahmed Khan blamed an air-conditioner on the seventh floor for the blaze moments after the flames were doused. "It isn't possible to say right now if the air-conditioner was on the entire night or the fire started when it was switched on in the morning. Our department will investigate," he said.

Later in the day, a UPS (uninterrupted power supply) unit was identified as the most likely cause of the fire.

None of the ministers, senior cops and fire department officials who visited the New Secretariat made any mention of the building being ill-equipped to fight a blaze. City police commissioner Surajit Kar Purkayastha restricted himself to praising the fire brigade for a job done well. Fire minister Khan declined to comment on the building's fire preparedness.

Minister Subrata Mukherjee, whose room on the seventh floor was damaged the most, said he had lost many important documents along with data stored in computers. Mayor Sovan Chatterjee wouldn't say anything other than that a forensic investigation would "reveal the exact cause of the fire".

Since 2011, the Mamata Banerjee government has initiated action against several businesses and individuals for not complying with fire-safety guidelines. Eight members of the erstwhile board of directors of AMRI Dhakuria had been arrested after the fire in Annexe 1 on December 9, 2011, that claimed 93 lives.

The government had also cancelled AMRI's licence under the Clinical Establishments Act a day after the fire tragedy. AMRI has been allowed to reopen some facilities but Annexe I is still shut.

Chatterjee International Centre was entirely shut for four days after a blaze last September affected two floors of the building. The unaffected floors of the building were given permission to reopen after the owners gave a written undertaking to the government that they would implement all fire-fighting guidelines within three months.

Firemen who fought the New Secretariat blaze on Friday said the fire wouldn't have spread as much as it did if the basic safety guidelines had been followed.

The 55-metre Bronto Skylift that can reach as high as 19 floors couldn't be used because there was not enough "headspace" at the entrance to take it close to the building, sources said.

But fire minister Khan insisted that fire brigade officials decided not to use the skylift because the blaze was under control by the time it arrived at 11.15am. The marble tiles that were removed to create space for the skylift to move told a different story.

"It is a new building compared to many other government structures but nobody apparently gave much thought to fire safety during its construction," a fire brigade official said.

He quoted officials of the public works department as saying they had never seen a drill to train the employees working across the 13 floors how to evacuate in the event of a fire threat.

"Regular fire drills would have also revealed that most of the hydrants in the building meant to draw water from the reservoir aren't working. There are around 300 hydrants but 80 per cent of them don't work," the official said.

The New Secretariat has three blocks: A, B and C. The fire broke out in Block A.

The seventh floor houses the office of the public health engineering (PHE) and panchayat minister Subrata Mukherjee, among other departments.

An employee of the PHE department said the scale of damage might have been less had the fire brigade been able to use the skylift. "The ladder would have given the firefighters better access to the origin of the blaze from outside. In the absence of a ladder, they had to spray water from the rooftop of Block C, which is far from Block A. At times, the water didn't even reach the source of fire," he alleged.

According to him, it took three hours for the flames to be doused because the firemen had to rely on guesswork to find safe entry into the building and reach the source of the blaze.

The challenge was made tougher by a breeze blowing inland from the Hooghly that fanned the flames. "The fire spread quickly from one office to another. Since the cubicles are made of plywood, almost the entire floor was in flames in no time," the PHE employee said.