The Hindustan Times said, citing unnamed officials, that the number of workers inside the building at the time of the incident has not been determined yet and that the identities of the victims have yet to be established.
The explosion was loud enough to be heard 5 kilometres away, according to reports. It reportedly damaged several adjacent buildings and caused a fire that at least five firefighting brigades were called to extinguish.
The NDTV broadcaster said, citing Bihar Chief Minister Nitish Kumar, that the families of the victims will be compensated 400,000 Indian rupees ($5,300).