The collapse was caused by the failure of connections supporting the fourth-floor walkway ceiling rods. This walkway crashed onto the second-floor walkway directly beneath, which in its turn fell to the floor of the lobby.

The Hyatt Regency walkway collapse in Kansas City (1981) was caused by a fatal design flaw in the support system of the fourth and second-floor suspended walkways. During construction, the original design—which called for a single long rod to support both walkways—was changed to a double-rod system without proper engineering review. This seemingly minor change doubled the load on the fourth-floor box beam connections. On July 17, 1981, during a "tea dance" event, the added weight of roughly 1,600 people caused the fourth-floor beams to fail, sending the walkway crashing onto the second-floor walkway below, and both then collapsed into the crowded lobby. The disaster killed 114 people and remains one of the most studied structural failures in history, leading to significant reforms in how engineering firms review "shop drawings" and manage on-site design changes.