Geotechnical site works are comprehensive, and they constitute the first step of the construction process. This study performs data mining of geotechnical works and analyzes the database for the root causes of accidents. The Occupational Safety and Health Administration (OSHA) was chosen for the 1984-2013 time frame with 247 cases. Descriptive statistical analyses were performed to discuss variables such as the end use of the work, project type and cost, soil type and condition, type and degree of injury, cause and type of accident, unsafe acts, and occupation and union status of the victim. The results showed that these accidents have a high frequency of recurrence and have a high severity level (54.3% fatalities). In addition, a total of 838 violations were recorded with penalties reaching 5 million US dollars. This study emphasizes that project-specific countermeasures should be taken regarding the root causes of accidents, leading to vigorous strategies to develop safety measures.