NANJING -- A fire was put out early Friday nearly nine hours after it engulfed a petrochemical company in east China's Jiangsu province, said the local work safety watchdog.

At 2:40 am, more than 100 firefighters extinguished the blaze, which started around 6 pm Thursday and triggered an explosion in a warehouse of Yanjin Petrochemical Co., Ltd. in Changzhou city, according to a statement from the city's industrial safety committee.

The fire swept through a 2,000-square-meter area where barrels of chemicals were stored, said the statement.

Over 200 residents who were evacuated have started to return home. Local environmental authorities said they did not detect pollutants from the fire in nearby water sources.

The industrial safety committee has ordered the plant to suspend operations and launched an investigation.