Panel releases findings on the deadly bonfire collapse.
The commission determined the structural failure was caused by excessive stresses on the lowest of the four tiers. Those stresses were heightened by excessive wedging of logs from the second stack into gaps in the lowest stack. The lowest stack, however, had inadequate wiring to hold it together. Steel cables used in recent years were not used in 1999, the commission found. The panel also found the logs were standing too vertical, the stack was overbuilt and the ground had a slight slope.