Lack of answers after Tianjin blasts

The overnight blasts, which claimed at least 50 lives and injured more than 700 people, originated in a warehouse used for storing dangerous chemicals. The detonations were preceded by a fire, Chinese officials said on Thursday.

"After firefighters reached the scene, then there was an explosion," Zhang Yong, the head of Binhai New District, told a press conference.

The causes of the fire and explosion were still under investigation, Zhang said, refusing to elaborate or provide any theories.

The officials also declined to comment on the type of chemicals in the containers.

Company manager detained

Firefighters had managed to bring the fire largely under control by morning, and the Tianjin government suspended further firefighting, allowing a team of chemical experts to survey the site.

There was no sign of toxic cloud after the explosion, but water samples were still being examined, according to local Environmental Protection Bureau official Wen Wurui.

Authorities have detained the senior manager of Ruihai Logistics, the company which owns the warehouse, according to state media.

'Minimize' the impact

Ships carrying oil and "hazardous products" were barred from the Tianjin port Thursday, the local Maritime Safety Administration announced on its official microblog.

Tianjin, in north China, is the 10th largest port in world. The city's harbor is a part of Binhai New District, a giant logistics hub twice the size of Hong Kong.

Operations at the port were "basically paralyzed" by the blast, the official China Securities Journal reported.

Large foreign companies ship large quantities of goods through the city, including cars, metal ore, coal and steel.

Danish shipping and oil group A.P. Moller-Maersk said operations at its Tianjin port terminals resumed Thursday. However, a few warehouses owned and operated by suppliers to its logistics company, Damco, were damaged.

Multinational resource company BHP Billiton said in a statement that its iron ore discharge berths were undamaged, but added said that "shipments and port operations have been disrupted" by the blast and it was working with its customers "to minimize any potential impact".

Thousands of cars burned

The Wednesday explosions destroyed 10,000 imported cars, according to the Qilu Evening News - 2,748 from German manufacturer Volkswagen.

An official with France's Renault told the AFP news agency that at least 1,500 of its vehicles had been destroyed.

Volkswagen and the aircraft maker Airbus also have manufacturing facilities in the area, but they have reportedly suffered no damage.

Binhai New District is also a home to one of the world's fastest supercomputers, which was shut down as a precaution. The machine was itself was running normally after the blasts, according to Chinese Xinhua agency, but the building housing it was damaged.

dj/rc (AFP, AP, dpa)