Customs officers in Shanghai's Yangshan Port seized 106.5 tons of smuggled fireworks, equivalent to 12 tons of TNT explosives, last year, the customs office announced on Friday.
The haul included the seizure in late 2015 of one consignment of fireworks weighing 20.5 tons destined for the Middle East and Africa.
It was in containers labelled cloth, handicrafts and soccer goods, but officers opened them after their sensing devices picked up suspected radiation.
Fireworks must be declared at customs for safety reasons.