Another 28 people were injured in the 6:30 a.m. explosion in the village of Dongzhai in Shanxi province, the Xinhua News Agency said. It said the cause under investigation.
Shanxi is a major coal-producing area where explosives often are made in unlicensed workshops that lack required safety equipment and stored in private homes.
In April, 31 people were killed in Shanxi when a two-ton (1.8-metric-ton) cache of explosives blew up at a hospital. A hospital administrator who moonlighted as a coal mine manager admitted storing the explosives at the hospital, the AP reports.
Last month, in another village in Shanxi, 10 people were killed when a blast ripped through a building where dynamite was being made illegally, according to news reports.
Elsewhere in Shanxi, six people were killed in February when a cache of explosives stored in a house blew up.