Abstract: At 2:20 p.m. on July 8, 2019, an employee working as an electrician for a city department of transportation was preparing to repair damaged traffic light communication lines. The employee entered a 10-foot by 20-foot underground electrical vault located 12 feet below the street, to troubleshoot and repair the signal connection. The employee was in the process of locating the fish tape used to run conduit to the vault. Minutes after entering the space, while the employee worked at the rear of the vault, a light rail train started approaching. The employee heard noises and yelled to his coworker inquiring about the noise. The narrative does not indicate if the coworker had time to respond. About this time, an explosion from the electrical lines occurred in the vault. The coworker explained that the front portion of the vault was connected to a chimney leading to the entrance of a manhole. Following the explosion, the entrance had completely shifted due to debris and the rear portion of the vault had collapsed on the employee. This caused the original ladder that the employee had used to enter the vault to become dislodged and crushed from the shifting vault. The coworker saw the employee drag himself to the base of a second portable ladder placed through the manhole opening. The employee was able to self-rescue using the second ladder. The employer reported a large 20-foot by 20-foot by 60-foot sink hole had been discovered after the vault had been moved and partially collapsed. The employer suspected a water main break and local flooding led to the incident. The employee fractured his ribs and punctured a lung. The employee was transported to the local hospital shock trauma unit and then moved to the intensive care unit (ICU) to recover before being released.