OSHA — the Occupational Safety and Health Administration — is a regulatory agency under the U.S. Department of Labor. It sets and enforces workplace safety law within the United States, and its best-known programs are the OSHA 10-hour and 30-hour outreach training cards.
IOSH, by contrast, is a UK-chartered professional body for safety practitioners. It offers globally recognized qualifications such as Managing Safely, but it is not a government regulator and has no legal enforcement authority the way OSHA does.
For contractors working on scaffolding and metal formwork in the Kingdom, both credentials are reliable indicators of safety competence, but neither substitutes for full compliance with local regulation — Saudi Labor Law, Civil Defense requirements, and the Saudi Building Code. Best practice combines internationally recognized training with complete local compliance.