Transportation of Carbon Dioxide (CO2) via high-pressure pipelines from source to storage site forms an important link in the Carbon Capture and Storage (CCS) chain. To ensure the safety of the operation, it is necessary to develop a comprehensive understanding of the consequences of possible pipeline failure. CO2 is a hazardous substance and an accidental release may lead to catastrophic damage. This paper describes an experimental investigation of the dispersion of CO2 in the atmosphere in a full-scale burst test of a pipeline containing high-pressure dense phase CO2. The experiment was carried out to simulate a CO2 pipeline failure in the real world. The test rig consisted of a buried 85 in long, 610 mm diameter pipeline test section connected at either end to 116 m long reservoirs. An explosive charge detonated at test section half-length initiated a rupture in the pipe wall top surface, releasing the high-pressure contents. The atmospheric dispersion of the CO2 following the explosive release was measured. The paper also describes Computational Fluid Dynamics (CFD) simulations of the dispersion of CO2 following the release. The CFD models were validated against the experimental data. The models were then extended to estimate the consequence distances related to CO2 dispersion following failure of longer pipelines of various diameters under different wind speeds and directions. Comparison of the results with prior studies was carried out.