Abstract: A communications worker was working alone in a telephone vault. He had placed a 3.7-meter-long ladder in the vault to enter and exit. The ladder had hooks at the top for placement over the top step of vault entrance, but the employee had not secured the ladder to the step. The top step of the vault was improperly placed, requiring those descending to climb toward the wall instead of the open area of the vault. Additionally, the bottom of the ladder was apparently resting on the floor of the vault, which was covered by about 150 millimeters of water. As he was climbing up the ladder to return to his truck to confirm that the proper circuit was being replaced, the ladder slipped out, moving across the concrete floor and causing the employee to fall to the floor of the vault. The employee broke his leg in the fall and was unable to exit the vault. A resident heard his calls 2 hours after the accident and summoned emergency rescue services. The employee was hospitalized for his injuries.