The HSE investigation focussed on the possibility of a faulty gas distribution system and found the castiron mains pipe was sunk in sandy-gravelly soil that was classified as "very aggressive" to "moderately corrosive".
BBC: Shrewsbury gas explosion 'no-one's fault' HSE concludes
2.
The corrosive nature of the ground soil and pressures from a nearby brick wall and telecom unit may have caused a fracture in the castiron mains pipe, the HSE said in its report.
BBC: Police awards for Shrewsbury gas explosion rescue