Smoke rises from oil refineries after explosion in Qingdao in east China's Shandong province in November. Pic: AP.

BEIJING (AP) — An official says a November pipeline explosion in northern China that killed 62 people was caused by sparks from a jackhammer that ignited oil that had leaked into the sewage system.

The massive explosion Nov. 22 devastated a suburb of the prominent port of Qingdao, leaving another 132 people injured. It ripped apart streets, tossed vehicles into the air and tore the fronts off buildings.

Spokesman for the State Administration of Work Safety Huang Yi told reporters Thursday a jackhammer being used to repair a manhole cover created sparks that ignited oil that had leaked due to corrosion in the pipeline.

Huang said human error was involved, and that both municipal officials and state oil company Sinopec bore responsibility. At least nine people have reportedly been detained over the disaster.