China Youth Daily
"China Youth Daily" reported that the contractor for the construction said the cause of the fire was probably sparks caused by welding work done on the 20th floor. Qiu Jingshu, a worker on the 18th floor, said sparks from welding being done on another building flew over and caused the scaffolding to catch fire. Afterward, it was "established" that the fire "was caused by unlicensed welders improperly operating their equipment", and several welders were arrested.