Swiss tests show how fast and violently electric vehicles can burn and note specific pollution risks in fire-fighting waters. The fire tests were carried out by AG/EMPA for the Swiss Federal Government, using charged batteries in scenarios representing a non-ventilated underground car park, a car park with sprinklers and a ventilated tunnel, using 1/8th of a full size battery in a similarly scaled-down enclosure. Within minutes of ignition, metre long flames are shooting out from the battery. Large amounts of black smoke and soot are emitted. The report concludes that the fire and smoke/soot dangers are comparable to those from an internal combustion engine car with fuel, but that the fire extinction waters are highly toxic. They also underline that after extinction, the battery must be kept under water to prevent reignition.
“Risk minimisation of electric vehicle fires in underground traffic infrastructures”, Swiss Federal Department of the Environment, Transport, Energy and Communications DETEC, ref. AGT 2018/006, August 2020 https://plus.empa.ch/images/2020-08-17_Brandversuch-Elektroauto/AGT_2018_006_EMob_RiskMin_Undergr_Infrastr_Final_Report_V1.0.pdf and media summary in French https://www.empa.ch/web/s604/standard-article-view-page/-/asset_publisher/lqGNyH2TDWyn/content/fire-test-in-a-tunnel/pop_up
AMPA TV video on YouTube (2 minutes) https://www.youtube.com/watch?v=2O07SIaxB08