Beijing: Of the scores of amateur eyewitness videos circulating widely on Chinese social media, few have captured the stunning impact of the blast that rocked the Chinese port city of Tianjin on Wednesday quite like this.

The clearly time-stamped security footage shows a man dressed in a dark T-shirt, apparently preparing to step out the double doors of a building, a few seconds before 11:36pm local time.

Without warning, a massive blast erupts, blowing in the building's doors as the man disappears under a wall of shattering glass; the security camera completely blanketed with thick smoke and debris.