The accident happened when an insecurely stored Preserving unlicensed cobalt-60 radiation source was recovered Recovering by scrap metal collectors who , together with a scrapyard worker , subsequently dismantled Destroying the container , unknowingly exposing themselves and others nearby to ionizing radiation .

A preliminary finding by investigators concluded Coming_to_believe that sparks from welding work being done on the building , undertaken by unlicensed welders , ignited scaffolding around the structure , which led to Causation the apartments ' destruction Destroying .

In all , sixteen individuals have been arrested Arrest in connection to the fire Catastrophe , as well as four others accused Judgment_communication of being unlicensed welders .