And in 2009 - the year the work was originally scheduled to be completed - the utility again requested $5 million for the same repairs, according to The Utility Reform Network (TURN).
"The money was spent on what they call higher priority work," TURN senior attorney Mike Florio told CNN.
PG&E's failure to make the scheduled repairs was originally reported Wednesday by the Los Angeles Times.
According to the documents filed in 2007, the utility identified the 62-year-old section of pipeline near the blast as one of the top 100 risks for failure, but "rescheduled the project" after reassessing priorities in 2009.
The section of pipe that exploded Thursday was the same age as the one slated for repair. The blast injured 52 people and destroyed 37 homes. Three people are still missing.
The utility told CNN that it "is committed to performing the work necessary to assure the safety of its gas transmission system."
Immediately following the explosion, PG&E pledged to establish a $100 million fund to help victims rebuild their homes.
While the original $5 million approved for the repairs hasn't been directly traced to a specific expenditure, TURN officials have speculated on where some of it ended up - in 2009, the utility paid out $5 million in bonuses for six executives, according to CNN.