NEW: Chemical specialists from the military have been sent in the area
NEW: More than 700 people have been hospitalized, dozens with critical injuries
Dozens of people remain missing
You can see the devastation everywhere: in the hollowed-out shells of buildings, in the anguished faces of relatives, in the parade of scorched cars.
But what set off the terrifying explosions that ripped through warehouses containing hazardous chemical materials, shooting fireballs across the sky and shaking buildings more than 2 miles away?
Hours later, amid the destruction in this northern Chinese port city of more than 13 million people, the cause of Wednesday night’s blast remained unclear.