Gas pipe judged hazard before fatal blast

The section of gas pipeline that ruptured and exploded in a suburban San Francisco neighbourhood, killing four and injuring nearly 60 others, was ranked as high risk because it ran through a highly populated area, state and federal authorities said.

One of the victims killed in the inferno on Friday worked for the commission reviewing Pacific Gas & Electric's investment plans to upgrade its natural gas lines, a colleague confirmed.

Longtime California Public Utilities Commission analyst Jacqueline Greig and her 13-year-old daughter Janessa died in the blast, which left a crater near their house and laid waste to dozens of 1960s-era homes overlooking San Francisco Bay.

Jessica Morales, 20, was also killed. One other victim found earlier has yet to be identified. Five people were still missing.