Abstract: At approximately 11:30 a.m. on February 26, 2014, Employee #1 and Coworker #1, employed by a construction company, were installing shoring in a trench in preparation for installation of sewer lines. The trench measured 60 feet long by 20 feet wide by 20 feet deep. Coworker #1 was working with his back to Employee #1. Coworker #1 heard a rumbling noise as a piece of shoring fell to the bottom of the trench. He turned and saw Employee #1, who was yelling, "Oh my back, oh my back!" Coworker #1 went to get the project foreman, who called for emergency services. Emergency services arrived and conducted a rescue of Employee #1 from the trench. A rescue operation was deemed necessary, not because Employee #1 was trapped, but because the emergency responders did not want to risk causing further injury to Employee #1's back. Employee #1 then was transported to University Medical Center (UMC), Las Vegas, NV, where he was admitted, treated for bruises to his back, and discharged the same day. This incident was investigated by two Compliance Safety and Health Officers (CSHOs) from Nevada OSHA. After arriving at the site at 1:45 p.m. on February 26, 2014 and following the Opening Conference, the CSHOs took photographs of the trench, the surrounding area, and the failed shoring. The CSHOs saw that the shoring that failed had a leak on one end of the cylinder. The employer's Safety Director stated he believed the shoring had failed in this area. The Trench Shoring Company was identified as the provider of the shoring. The employer's Safety Director stated that a representative of the Trench Shoring Company inspected the failed shoring and agreed that the seal in the cylinder failed. The employer was requested to provide documentation affirming this claim. On March 25, 2014, Nevada OSHA received a letter forwarded by the employer. The letter, from The Trench Shoring Company, stated that The Trench Shoring Company was not able to conclude what happened to the shoring. On March 14, 2014, two Nevada OSHA CSHOs returned to the site to obtain an air screening due to the high volume of vehicle traffic and heavy equipment operating in the area. The readings showed no signs of any elevated levels. The investigators made several attempts to contact and interview Employee #1, including a certified letter mailed March 17, 2014, but received no response. Therefore, on April 2, 2014, they proceeded to conduct a Closing Conference with the employer's Safety Director by phone.