A fire broke out around 10:30 am Thursday at a petrochemical refinery in Pudong New Area, local media reported. No injuries or deaths were reported.

The fire started in one of the reformation workshops in the refinery, which is owned by Sinopec Shanghai Gaoqiao Co, the Shanghai Evening Post reported.

"There were flames and thick black smoke, though I didn't hear the sound of an explosion," said an eye witness surnamed Wu, whose office is about one kilometer away from the refinery.

Firefighters extinguished the blaze in 30 minutes, according to the report.

The explosion that started the fire was caused by a mixture of hydrogen and gas, but no further details were released Thursday as authorities continued to investigate.

The Shanghai Environmental Protection Bureau announced on its microblog that it didn't identify any air pollution coming from the fire.