1.   Internal ignition source possibilities include faulty wiring, static buildup, or a defective fuel pump.

2.   They argued that it resulted from an electrical spark from a defective auxiliary fuel pump, though they had no direct evidence to support that theory.

3.   A German nuclear power plant will be shut down for a week from Thursday to replace defective fuel elements, authorities in the northern port city of Kiel said.

4.   According to US media reports, a defective fuel probe could have caused a spark that might have ignited fuel vapors, leading the nearly empty tank to explode.

5.   The lawyer claims a defective fuel pump caused a spark that led to an explosion in the central fuel tank, which was nearly empty but contained fuel vapors.