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Pipefitter Dies When Excavation Wall Collapses, Causing Water Tank to Rotate and Pin Him Against Excavation Wall

Michigan Case Report: 12MI121
Release Date: October 28, 2013

The following report is the product of our Cooperative State partner and is presented here in its original unedited form from the state. The findings and conclusions in this report are those of the individual Cooperative State partner and do not necessarily reflect the views or policy of the National Institute for Occupational Safety and Health.


In fall 2012, a male sprinkler fitter/pipe fitter in his 40s died when he was struck by and pinned against the wall of an excavation by a water tank which had pivoted due to an excavation wall collapse (Figure 1). The excavation was dug by another contractor, who was the designated competent person. The soil was water saturated clay. Two feet of fill sand was atop the clay. The excavation had been partially completed the day prior to the incident and completed the day of the incident. The excavation was approximately 40 feet long by 14 feet wide by 14 feet deep. The excavation walls were nearly vertical and were not shielded or shored against collapse. It rained the night prior to the incident. On the day of the incident, the excavator operator N Location of Decedent Location of wall collapse causing tank to pivot Ladder placed in excavation after incident 2 lowered an empty 20,000-gallon, 10-foot-wide by 37-foot-long by 8-foot-high water tank that weighed approximately 5,700 pounds onto a one-foot-deep sand base. The tank was anchored via tie down straps to concrete deadman anchors. The decedent and another coworker were on the east side of the excavation getting ready to exit when the northwest corner of the excavation collapsed into the excavation causing the tank to pivot in a clockwise direction. The decedent was pinned by the tank against the east wall of the excavation. The excavator operator moved the tank to the west, freeing the decedent. Coworkers administered CPR while emergency responders were enroute. Emergency responders entered the excavation and continued resuscitative efforts. The decedent was declared dead at the scene.

Pipefitter Dies When Excavation Wall Collapses, Causing Water Tank to Rotate and Pin Him Against Excavation Wall [PDF 898 KB]