According to China’s Maritime Safety Administration (CMSA), the shipping container explosion aboard the box ship YM Mobility at Ningbo in 2024 was caused by thermal runaway in a cargo of organic peroxides.
The container in question was a refrigerated shipping container filled with tert-butyl perbenzoate (TBPB), a common activator for making plastics like polyethylene and polyester. It becomes unstable at high temperatures, and its safety-critical temperature is 140°F, at which it begins its runaway reaction. This particular shipment was headed to a terminal that requires refrigerated storage for TBPB. Hence, the manufacturer packed it in a refrigerated box so that it could be plugged in on arrival.