A volunteer puts up a missing person notice on Friday at a temporary relocation site in a Tianjin primary school. Volunteers say three of the missing persons have been found with the help of the notices. Photo: CFP

Heavy causalties caused by the explosion in Tianjin have led to questions about the safety of the warehouse where chemicals were stored.

As 21 firefighters were confrimed  dead in the explosions, media speculated that  less experienced firefighters uninformed of the nature of the hazardous materials being stored might have sprayed chemicals that react explosively to water. Among the deceased, the youngest fireman was 18 years old.

However, Liu Yutao, a 19-year-old firefighter who was among the first responders, told the Global Times on Friday that "they had not been informed of which chemicals were stored in the cans that stood near burning containers."

"After being told to stay away from containers by a person in charge of the containers, we began to withdraw while using water cannon to cool cans down," recalled Liu, who was to be discharged from Tianjin Teda Hospital, the closest to the blast zone.

The first explosion took place when they retreated about 100 meters, he said.

"The first step to put out the fire is to cool [warehouses] down … but they were not so dumb as to not realize that calcium carbide can be detonated by spraying water," Lei Jinde, a publicity official at the Ministry of Public Security's fire department, was quoted by news site thepaper.cn as saying on Thursday.

Gao Huaiyou, deputy director of Tianjin's work safety watchdog, said on Friday the dangerous chemicals stored at the warehouse that exploded Wednesday night in Tianjin Port cannot be identified yet, the Xinhua News Agency reported.

He cited  damage to the company's office and major discrepancies between the accounts of company management and customs records as a reason they have not been able to identify the chemicals.

Cargo is stored in a warehouse for no more than 40 days before being transferred elsewhere, he said.

Li Qinglu, a chemical professor at Shenyang University of Chemical Technology, told the Global Times that "warehouses for chemicals in particular are strictly regulated, and each type of chemical should be separated by at least a kilometer."

However, temporary warehouses on open ground are not always checked properly, even if hazardous chemicals are stored there, a senior port manager who asked for anonymity told the Global Times.

Gao said that the Tianjin Dongjiang Port Ruihai International Logistics storage firm passed a safety assessment for temporarily storing hazardous chemicals.

The Zhongbin Haisheng Technology Development Co, which conducted the assessment, was singled out by the State Administration of Work Safety for failing to provide a accurate safety assessment, news site thepaper.cn reported on Friday.

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