A new video shows last week's destructive explosion in San Bruno that killed seven people and destroyed dozens of homes.

The video was taken from a gas station on Thursday. It shows a huge fireball forming, and people at the gas station running for their lives. The video also shows flames billowing as cars on the road next to the gas station come to a stop.

Authorities are continuing to investigate the gas line blast, searching for a possible cause.

A sophisticated safety inspection device required for many large natural gas pipelines couldn't be used in the San Bruno line because of design issues. However, the utility that owns the line said Monday that it had complied with all federal testing requirements.