HONG KONG — An explosion Thursday afternoon at a chemical plant in eastern China killed at least 47 people, the state media said Friday morning.

The blast, in Xiangshui County in Jiangsu Province, sent a fireball and thick plumes of black smoke into the air and raised concerns about chemical contamination in the area. The China Earthquake Administration reported a magnitude-2.2 earthquake at 2:48 p.m. that was believed to have been caused by the explosion.

In addition to the 47 killed, at least 90 people were seriously injured in the explosion at the Jiangsu Tianjiayi Chemical Company, CCTV, the state broadcaster, reported Friday. Videos circulating online showed people who appeared to have been cut by glass and other debris.