Abstract: At approximately 10:30 a.m. on June 10, 1994, Employee #1 was standing in an excavation guiding a temporary manhole cover that had been lowered by a tracked backhoe. The bucket was attached to the backhoe with a JB Hendrix quick coupler, serial #C2013. The bucket fell off the backhoe, striking Employee #1 and causing serious multiple injuries. The bucket came to rest against the precast manhole body. The bucket, backhoe, and quick disconnect device were examined by a mechanic after the incident. No defects were found. The operator stated that he had attached the bucket, then raised it and shook it numerous times to make certain that it was locked in place. He also said that he tilted the bucket to observe the position of the helper springs. He said they were not compressed, indicating closure. This procedure had been initiated after a noninjury incident on May 24, 1994. After the June 10 injury, the employer instituted a procedure requiring the operator or another employee to check quick coupler closure by feeling the position of the closure device after the bucket is shaken and placed at rest. This investigation disclosed no mechanical or procedural failures.