PVTIME – A transportation-related energy storage safety incident unfolded in St. Francis County, Arkansas on 11 August, involving an 82,500-pound Tesla Megapack unit. The grid-scale storage device fell from its transit trailer during highway travel and ignited, with residual fires fully extinguished only on the following morning of 12 August.
Photo courtesy of the Forrest City Fire Department
Records from the Forrest City Fire Department confirm that the incident occurred at the 260-mile marker on the Interstate 40, near the Shell Lake exit. The Megapack dislodged and overturned onto roadside grass due to driver error while approaching the exit ramp. The structural impact triggered an immediate thermal runaway in the lithium-ion battery, which spread flames rapidly across adjacent grassland areas. The inherent complexity of suppressing lithium-ion fires necessitated an extended on-site emergency response.
Sustained southerly wind patterns carried smoke towards Interstate 40 throughout the mitigation efforts. Fire crews maintained continuous water cooling of the battery assembly to contain smoke dispersion and eliminate reignition risks. White Motor Company technicians stabilised, lifted and relocated the faulty unit to a secure location where controlled burn-off protocols were applied to eliminate any remaining dangers. Tesla dispatched specialist personnel to provide technical support for the on-site emergency response.
The incident resulted in no casualties and caused no disruption to traffic flow on Interstate 40. The competent authorities are still conducting an inquiry to establish the exact cause of the transportation failure and formal liability.
Tesla’s official emergency protocols for commercial Megapack assets set out strict response measures for thermal anomalies. The company requires immediate evacuation of the site at the first sign of smoke or fire, and prohibits emergency teams from opening compromised Megapack casings. Each unit features an engineered directional venting system designed to safely discharge the heat, smoke and flames produced during a thermal runaway event, thereby minimising the risk of secondary hazards.
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