2-3 days back, I read a news item in a regional news paper that there was fire while transferring a solvent with a plastic bucket from drums. There were sparks followed by big fire.
It is clearly due to static charge builtup during dipping of plastic bucket in drums containing solvent. Static charge is generated due to friction between conducting (metal drum) and non-conducting (solvent, bucket) media. For solvent transfer, one should provide proper piping arrangement with earthing and bonding to dissipate the charge accumulated.
Few years back, I read a case study in which a fire occurred while transferring the solvent through braided plastic hose. Investigation revealed that the electrical continuiity was broken as there was no contact between the nozzle and the metal braid reinforcement to the hose. During transfer for extended time, the accumulated charge on the hose discharged as spark causing fire.
Hence, earthing and bonding are important aspects and one should avoid short term measures like bucket transfer to avoid recurrence of such fire incidents. Further, the operators should not wear synthetic dress (wear only cotton dress), wear antistatic foot wear, ensure turbulence, nozzle spray, etc to avoid static charge generation/accumulation.