FEMA 403, APPENDIX C Click to access fema403_apc.pdf Forensic Metallurgy Metallurgical Examination of WTC Steel Suggests Explosives Although virtually all of the structural steel from the Twin Towers and Building 7 was removed and destroyed, preventing forensic analysis, FEMA’s volunteer investigators did manage to perform “limited metallurgical examination” of some of the steel before it was … Continue reading FEMA 403, APPENDIX C