Three construction workers of a family – a father, son and nephew – died Wednesday in Hyderabad’s LB Nagar after tonnes of debris from a soil collapse buried them in the freshly excavated basement of a proposed multi-storey residential building.

A Veerayya (40), his son A Ramu (20) and the latter’s cousin M Sreenivas (18) were natives of Khammam district employed at the construction site for around 10 days.

They were paid daily wages of Rs 900 each. The soil collapse occurred just as the deceased and a critically-injured fourth worker started pouring concrete into the basement.

Earthmoving equipment was used to remove around two tonnes of soil and extricate the bodies. Concern over suspected violation of safety norms was accentuated by indications that the basement wall had become unstable because of moisture incursion. Excavation was completed barely two weeks ago, sources said.

Civic officials said soil erosion occurred in the corner portion of the cellar. The developers allegedly excavated that portion without submitting the stipulated commencement notice to the civic authorities under Section 440 of the GHMC Act.

“This accident was a direct consequence of rule violations and negligence of the owner/developer, who failed to comply with the safety measures and conditions specified in the building permit order. We have written to the station house officer of LB Nagar police station to file a criminal case,” a GHMC official said.

A police officer said an FIR has been registered and all responsible parties, including the contractor, builder, and site engineer, will be held accountable. “Upon inspecting the location, we observed that the accident occurred in a dangerous area where labourers ventured deep into the cellar to carry out their task,” said the official.

A preliminary police investigation revealed that the developer received permission for a G+4 structure with two cellars but intended to build a nine-storey apartment block.