Facts you need to know about deadly blasts in Tianjin

Editor's note: A massive warehouse explosion in Tianjin shocked the nation, sending it into deep grief. Fragmentary pieces of information are flooding into social media and we have turned those scraps of info into basic facts you need to know about the tragedy.

[Overview]

Smoke and fire are seen after an explosion in the Binhai New Area in North China's Tianjin municipality on Aug 13, 2015. [Photo/Xinhua]

An explosion ripped through a warehouse at the Binhai New Area in Tianjin at 11:34 pm on Wednesday. The warehouse stores dangerous chemical goods.

Residents near the site said shockwaves from the explosion broke doors and windows. The impact could be felt in areas of Hebei province, several kilometers away.

The near-earthquake magnitude of the first blast was 2.3, the equivalent of detonating three tons of TNT. The second blast happened 30 seconds later and it was even more powerful, the equivalent of 21 tons of TNT, according to the China Earthquake Administration.

Another two major blasts occurred at 9 am on Thursday. A series of small explosions came around every 10 minutes.

Binhai New Area special economic zone is part of the Bohai economic rim and home to numerous Fortune 500 companies. A cluster of logistics companies operate in the area immediately surrounding the blast site and virtually everything within a three-kilometer radius as been damaged or destroyed: shipping containers lie crumbled on the dockside, port buildings are reduced to twisted metal frames.

About 1 km away are two residential communities where burned-out cars block the streets and broken glass litters the ground. Most of the dead and injured are migrant workers who live in these communities. Many fled their homes in pajamas after being thrown from their beds by the force of the blasts.

President Xi Jinping and Premier Li Keqiang have urged all-out efforts to save people and warned that "those responsible will be seriously handled".

Public Security Minister Guo Shengkun is on site and personally leading the emergency response.

The warehouse belongs to Tianjin Dongjiang Port Ruihai International Logistics Co. Ltd, a company licensed to store, distribute and import dangerous chemicals. The cause of the blast is still unknown but some company executives have already been detained by police.

[Casualties]

Medical staff transport a person injured from the explosion of the Binhai New Area to a hospital affiliated with the college of armed police force in Tianjin, North China, Aug 13, 2015. [Photo/Xinhua]

As of 7:20 pm on Thursday, the death toll has risen to 50, including 17 firefighters, most of whom are post-90s. About 701 people have been admitted in hospital, among whom 66 are severely injured. At least 21 still missing.

Six firefighters killed on duty have been identified, and another 66 wounded have been hospitalized.

Doctors say most of the patients suffered burns, bruises, bone fractures and injuries related to shockwaves.

The Tianjin Port Group Co. said dozens of its employees were unaccounted for and a search operation is under way.