Fire brigade officials in Durgapur said on Wednesday that excessive use of inflammable materials for interior decoration and the failure to replace the outdated electrical wiring system at the Asansol-Durgapur Development Authority (ADDA)'s headquarters were the reasons for the blaze to spread fast and leave the 9,000sqft office here completely charred on Tuesday.

After inspecting the charred second floor of the building, the fire officials said preliminary investigations suggested that a short-circuit in the old electrical wiring had caused the blaze.

"Instead of overhauling the old electric wires, they used highly inflammable objects like plywood and fibre to cover the dated electrical wiring. The cosmetic makeover gave the office a smart look but exposed it to a fire that gripped the office on Tuesday. The inflammable materials helped the fire spread fast, while there was no firefighting system in place to control such an eventuality," said a senior fire official in Durgapur.

In the 2014-2015 fiscal, the ADDA had renovated the office at a cost of over Rs one crore. The interiors were overhauled to give it the look of a modern corporate office. The three-storey building also got a new coat of blue and white paint.

While ADDA officials focussed on cosmetic changes, they did not take basic fire safety measures, said a senior fire brigade personnel.

"While Rs one crore was spent on the renovation, basic safety measure like installing a fire alarm was not done. In the absence of fire and smoke alarms, the blaze could not be noticed immediately and night guards on duty realised the incident only after it had spread beyond control," said a fire department official.

The ADDA is nodal agency of the Bengal government to implement development projects and is the authorised lessor of commercial and domestic plots in its 1,600-sqkm area of operation in West Burdwan.

The fire broke out on the second floor of the ADDA headquarters around 2am on Tuesday and a dozen firefighting engines were deployed to douse the blaze. After an eight-hour-long battle, firefighters managed to douse the leaping flames. By then the office was left charred.

It is not that ADDA officials were unaware of the absence of fire safety measures in its office. During annual inspections, fire officials of the Durgapur zone repeatedly highlighted the severe lapses of fire extinguishing system at ADDA but no steps were taken, a fire official said.

Asked why steps were not taken to make the office safe from fire hazards, a senior ADDA official said: "We were aware of the lack of adequate fire safety measures but could not install those as it involved a major expenses."

In 1994, a fire broke out at the ADDA building but it did not turn into a major one as most furniture was made of hardwood or iron, a fire official said. While plywood was not used in making the furniture, walls and ceiling were made of concrete.

"Hardwood and iron are not highly inflammable and the concrete walls and ceilings did not allow the fire to spread fast," said a retired ADDA official.

On Wednesday, a team of forensic experts inspected the charred office and collected samples.

The ADDA officials opened a makeshift camp office on Wednesday. ADDA chief executive officer (CEO) Akansha Bhaskar said: "From Thursday, we will start a temporary office on the first floor of the building that has remained unaffected by the fire. The ADDA is awaiting a green signal from fire officials and PWD engineers to start the temporary office."