The Occupational Safety and Health Administration (OSHA) is the federal agency under the Department of Labor that enforces workplace safety regulations across most industries including construction. The construction-specific safety regulations are codified in 29 CFR 1926 covering fall protection, scaffolding, electrical safety, excavation, hazard communication, personal protective equipment, and many other construction risks.
OSHA enforces through both planned inspections and complaint-driven inspections. Penalties for violations range from minor citations to willful-violation penalties exceeding $150K per violation. Several states (California, Washington, Oregon, Michigan, others) operate their own OSHA-approved state programs (Cal/OSHA, etc.) that meet or exceed federal standards. Maintaining a written safety program and documented training is the standard defense against OSHA enforcement.