You are cleaning the tanks after carrying a cargo of crude oil. Which statement is TRUE? （）

A、Washingwatershouldberecirculatedifpossiblebecauseithasthesameelectricpotentialasthecargotankbeingcleaned
B、Thehosestoportablecleaningmachinesshouldbedisconnectedbeforethemachinesareremovedfromthetank
C、Theprincipalhazardwithsteamingcargotanksisraisingtheambienttemperatureabovetheflamepointofthecargoresidue
D、Steamcleaningandwaterwashingarebothcapableofgeneratingelectrostaticchargeswithinatank