"The construction work involved replacing aging pipes in the area with plastic lines. But the National Transportation Safety Board said the utility failed to tell the construction crew about disconnecting or relocating the sensor, allowing the device to detect a drop-off in pressure in the abandoned line and signal to a nearby control station to increase the flow of gas into the system."
Apparently the control system did not include safety checks, pre-commisioning checks.
Moderator’s note: This message doesn’t include any background information. For those of you who haven’t heard, up in the north shore area of Massachusetts we had multiple gas explosions last month that lead to some major fires and several people were killed.