China on Friday released an official report over the deadly warehouse blasts that killed 165 people in a Chinese port city in August, as investigators concluded that the disaster was triggered when a chemical stored in an unlicensed facility became too dry and caught fire.
A total of 49 people have been detained, the government said on Friday, while putting losses at more than $1 billion.
An investigative team assembled by the State Council, China's Cabinet, said that the flames spread among stocks of nitrocellulose, a flammable compound used as a binding agent with medical applications and as an ingredient of lacquer. The flames then spread to illegal stores of the combustible fertilizer ammonium nitrate, touching off two massive explosions.
On August 12, explosions at a chemical warehouse in Tianjin left 165 people dead, and eight people missing, as 798 were injured in the incident.
Previously, the investigators had said that the warehouse regulators failed to enforce safety rules; including, regulations on hazardous materials along with not having proper licenses for months. Authorities detained several dozen people, including senior executives of the company and local government officials.
Twenty-five officials will face prosecution over the blasts on suspicion of dereliction of duty, abuse of power and bribery, the official Xinhua News Agency reported, citing the Supreme People's Procuratorate.
The investigators said that stocks of nitrocellulose, at the Ruihai International Logistics warehouses, became too dry due to the loss of humidifying agents, and began to heat up in the hot summer weather. The material then started to burn, they said.
"The key is that ammonium nitrate was not supposed to be stored there at all," Du Lanping, a leading investigator, told state broadcaster CCTV.
"Then, the firefighters were not told of its existence, so the commanders could not make sufficient risk assessments."
When the chemicals exploded, the firefighters were too close to evacuate safely, Lanping added.
The investigators said that Ruihai ignored many safety precautions and its safety management was "extremely chaotic." Investigators blamed local officials for failing to enforce safety regulations and provide adequate supervision.
"If the proper approval procedures had been followed, Ruihai would have never been allowed to exist in the first place," another leading investigator, Li Wanchun, told CCTV.
The blasts caused air, water, and soil pollution in the region but did not affect the environmental quality of the ocean bay on which Tianjin sits, the investigators said.
The explosions were so large that they were captured by satellites from space. Residents in nearby districts have said the blasts shattered the windows of many homes.