1.   Police, quoting witnesses, said the fire, believed to have started by welding sparks, spread rapidly upward, trapping several dozen workers.

2.   A welding spark ignited oil spilled nearby in the engine room, MBC said.

3.   Spanish National Radio reports indicated the blast may have been caused by a welding spark near an accumulation of propane gas.

4.   The ensuing leak was set off by a welding spark.

5.   Welding sparks may have been to blame, he said.

6.   Welding sparks were believed to have ignited the blaze, police said.

7.   Yonhap news agency reported that the fire may have been caused by a stray welding spark from a renovation worker.