cut to prevent fires. A total of 114 were killed and 216 injured, 29 of whom were rescued from the rubble. Investigation The Kansas City Star hired architectural engineer Wayne G. Lischka and national engineering firm Simpson, Gumpertz, and Heger Inc. to investigate the collapse, and Lischka discovered a significant change to the original design of the walkways. Within days, a laboratory at Lehigh University began testing box beams on behalf of the steel fabrication source. The Missouri licensing board, the state attorney general and Jackson County investigated the collapse over the following years. Edward Pfrang, lead investigator for the National Bureau of Standards, characterized the neglectful corporate culture surrounding the entire Hyatt construction project as "everyone wanting to walk away from responsibility". The NBS's final report cited structural overload resulting from design flaws where "the walkways had only minimal capacity to resist their own weight". Pfrang concluded they would have failed with one-third of the occupants' weight. Investigators found that the collapse was the result of changes to the design of the walkway's steel hanger rods. The two walkways were suspended from a set of steel hanger rods, with the second-floor walkway hanging directly under the fourth-floor walkway. The fourth-floor walkway platform was supported on three cross-beams suspended by the steel rods retained by nuts. The cross-beams were box girders made from C-channel strips welded together lengthwise, with a hollow space between them. The original design by Jack D. Gillum and Associates specified three pairs of rods running from the second-floor walkway to the ceiling, passing through the beams of the fourth-floor walkway, with a nut at the middle of each tie rod tightened up to the bottom of the fourth-floor walkway, and a nut at the bottom of each tie rod tightened up to the bottom of the second-floor walkway. Even this original design supported only 60% of the minimum load required by Kansas City building codes. Havens Steel Company had manufactured the rods, and the company objected that the whole rod below the fourth floor would have to be threaded in order to screw on the nuts to hold the fourth-floor walkway in place. These threads would be subject to damage as the fourth-floor structure was hoisted into place. Havens Steel proposed that two separate and offset sets of rods be used: the first set suspending the fourth-floor walkway from the ceiling, and the second set suspending