According to European Union requirements and directives, the further development of the power industry based on hydrocarbon fuels is only possible with the application of CCS technologies in power plants. These technologies will greatly reduce carbon dioxide emissions into the atmosphere. Although carbon dioxide is not considered to be a toxic gas and its slight amounts are included in atmospheric air, in big concentrations it can pose a health or even life hazard to both humans and animals. Analyzing the individual stages of CCS technology, it may be concluded that the greatest risk is created by a potential failure of the pipelines transporting CO₂. In the case of failure, huge amounts of CO₂ may get into the surroundings, increasing its concentration in the closest vicinity of the damaged pipeline. This article identifies potential hazards to the environment resulting from these technologies. The gas transportation stage is considered most dangerous one. Sample results of the calculation of the hazard zones around pipelines transporting CO₂ under very high pressure are given. The hazard zones around a pipeline without the safety valves may include an area with a radius of 200 m.