Addresses OSHA 29 CFR 1926.651 - 1926.652. Excavation and trenching accidents are a leading cause of disabling injuries and suffocation in the construction industry. Cave-in prevention is the critical message of this comprehensive, web-based program. Throughout the course, several different forms of shoring in a variety of different work sites demonstrate best safety practices to follow on the job. This online program covers: Overview of protective systems, Regulatory requirement, Best safety practices.