According to the report, the double blasts were caused due to spontaneous combustion of nitro-cotton in a container, which lacked a wetting agent that would have prevented the explosion. The nitro-cotton had self-ignited under high temperature, causing large areas of combustion. The flame further ignited dangerous chemicals, including the explosive ammonium nitrate, triggering the explosions.
Xinhua reports that after five months of investigation, the team has concluded that the disaster, "an extraordinarily serious production safety accident," was caused by ignition of hazardous materials, improperly or illegally stored at the site.
Tianjin Ruihai International Logistics Co. Ltd (Ruihai Logistics), owner of the warehouse, had "illegally built a freight yard of hazardous materials, conducted illegal operations, illegally stored hazardous material and had been running inept safety management," the report said.
The probe suggests 74 officials be subject to Communist Party of China disciplinary procedures, 48 be admonished by their local discipline inspection commissions. One other culpable person died of natural causes during the course of the investigation.
The report also recommends that Ruihai Logistics' licenses be revoked and company executives be banned from any other executive posts in the sector.