Two tanks containing residual diesel oil exploded around 2:20 p.m. at a PetroChina outlet in the city of Dalian, triggering a fire, firefighters with the city said. At least two people were injured and two others have been reported missing after the explosion. The cause of the blast is under investigation. [Photo/Chinanews.com]

Two tanks containing residual diesel oil exploded around 2:20 p.m. at a PetroChina outlet in the city of Dalian, triggering a fire, firefighters with the city said. At least two people were injured and two others have been reported missing after the explosion. The cause of the blast is under investigation. [Photo/Chinanews.com]

Two tanks containing residual diesel oil exploded around 2:20 p.m. at a PetroChina outlet in the city of Dalian, triggering a fire, firefighters with the city said. At least two people were injured and two others have been reported missing after the explosion. The cause of the blast is under investigation. [Photo/Chinanews.com]

Two tanks containing residual diesel oil exploded around 2:20 p.m. at a PetroChina outlet in the city of Dalian, triggering a fire, firefighters with the city said. At least two people were injured and two others have been reported missing after the explosion. The cause of the blast is under investigation. [Photo/Xinhua]

Fire fighters put out a fire at the accident site of oil residue tank blasts in a PetroChina outlet in Dalian, northeast China's Liaoning Province, June 2, 2013. At least two people were injured and two others have been reported missing after two tanks containing residual diesel oil exploded around 2:20 p.m. The cause of the blast is under investigation. [Xinhua]

Fire fighters put out a fire at the accident site of oil residue tank blasts in a PetroChina outlet in Dalian, northeast China's Liaoning Province, June 2, 2013. At least two people were injured and two others have been reported missing after two tanks containing residual diesel oil exploded around 2:20 p.m. The cause of the blast is under investigation. [Xinhua]

Fire fighters put out a fire at the accident site of oil residue tank blasts in a PetroChina outlet in Dalian, northeast China's Liaoning Province, June 2, 2013. At least two people were injured and two others have been reported missing after two tanks containing residual diesel oil exploded around 2:20 p.m. The cause of the blast is under investigation. [Xinhua]

Two tanks containing residual diesel oil exploded around 2:20 p.m. at a PetroChina outlet in the city of Dalian, triggering a fire, firefighters with the city said. At least two people were injured and two others have been reported missing after the explosion. The cause of the blast is under investigation. [Photo/Xinhua]