A massive explosion hit a "dangerous goods" warehouse in Tianjin, China, on Wednesday, killing at least 44 people and leaving emergency services staff trapped in the rubble.The explosion in the Binhai New Area on the city's coast happened at about 11.30pm local time, with videos posted on social media showed a towering inferno above one of China's largest urban areas.Report by official news agency Xinhua that 44 people were confirmed dead - including 12 firefighters - and as many as 400 injured. The Beijing News, an official outlet, reported that authorities had lost contact with 36 firefighters on the scene.