Investigators tonight confirmed that "component failure" caused a massive gas leak which forced up to 250 families to be evacuated from their homes in Co Tyrone.
Health and safety officials launched the probe after liquid petroleum gas escaped from a 30-tonne tank and formed a huge gas cloud over Coalisland.
Ten fire engines and 70 officers fought for 16 hours to contain the situation which senior officers said held "serious potential for loss of life".
Homes within a square mile of the source of the leak in the Annaghmore Road area were evacuated with up to 14 families forced to spend Monday night in a local community centre.
Mr John Francey, the Health and Safety Executive's Chief Inspector, said an initial examination of the equipment indicated that the gas escaped due to the failure of a thermometer housing and not damage to the tank itself.
"Whilst this investigation is ongoing, I can confirm that the storage tank does not pose any risk to the public's health and safety."
PA