A trench is considered a temporary excavation where both the length of the floor and the depth of the trench exceeds the width of the floor. Construction and underground utility service and repair are a few of the reasons trenches are dug. The large amount of underground infrastructure and construction happening in New York City increases the likelihood that FDNY units will respond to such a collapse. These incidents are deceivingly dangerous as they often occur with little or no warning and a high percentage of deaths that occur involve would-be rescuers. In this episode, host Battalion Chief Brian Mulry discusses trench rescue operations with Lieutenant Todd Smith, lead trench instructor at the FDNY Technical Rescue School and a member of Rescue Company 4 in Queens.