Infrastructure – Kolkata Warehouse Roof Collapse Report Reveals Major Construction Lapses

Infrastructure – A preliminary investigation by the Kolkata Municipal Corporation (KMC) has identified multiple construction failures that allegedly contributed to the deadly roof collapse at an under-construction warehouse in Kolkata’s Taratala area. The report points to poor execution, substandard building materials, and serious deviations from the approved construction plan as the primary reasons behind the incident.

Investigation Highlights Multiple Violations

According to the report submitted to the KMC Commissioner on Thursday, the warehouse project had received approval in February 2025 for construction on a 54-katha plot. A three-storey structure was subsequently developed, but investigators found that several key construction norms were ignored during execution.

Officials stated that the building process did not follow the prescribed sequence. Under standard construction practice, iron casting should begin from the first floor before progressing upward. However, in this case, casting work reportedly started from the third floor, placing excessive pressure on an inadequately prepared structure that was unable to withstand the load.

Poor-Quality Materials Raised Safety Concerns

The municipal report further noted that low-grade materials were used during the casting process, weakening the building’s structural strength. Investigators believe this significantly increased the risk of failure during construction.

Another major finding was that the foundation and lower sections of the building had not been reinforced sufficiently before the upper floors were constructed. The absence of proper structural support is believed to have played a critical role in the collapse that occurred on Thursday afternoon.

Expansion Beyond Approved Limits

The inquiry also revealed discrepancies between the sanctioned building plan and the actual construction. Although the approved design covered 43 kathas of the 54-katha land parcel, investigators found that construction activities had extended onto an additional five kathas without official approval.

Authorities said the warehouse dimensions were expanded beyond the sanctioned plan, raising further questions about compliance with municipal regulations. These unauthorised modifications are now part of the ongoing investigation.

Supervision Failures Also Identified

While the building department concluded that the original structural design itself did not contain technical flaws, the report highlighted serious shortcomings in construction supervision. Officials responsible for monitoring the project, along with those directly involved in the construction work, have been accused of negligence.

The department also acknowledged that a shortage of staff has affected routine monitoring of large construction projects across the city, making it more difficult to detect violations at an early stage.

Casualties and Police Investigation

The warehouse roof collapse claimed the lives of nine workers, while 20 others sustained injuries. All injured workers were taken to SSKM Hospital for treatment, where two remain in critical condition, according to officials.

The police have arrested five individuals in connection with the incident. A suo motu First Information Report (FIR) has been registered under multiple provisions of the Bharatiya Nyaya Sanhita (BNS), including charges related to culpable homicide and attempt to commit culpable homicide.

To ensure a comprehensive inquiry, Kolkata Police have constituted a Special Investigation Team (SIT). The team is expected to examine the circumstances leading to the collapse, assess whether construction rules were deliberately violated, and determine the responsibility of all individuals connected with the project.