The report provides an overview of potential inputs of hazardous substances from the offshore oil and gas industry into the North Sea. Emissions from drilling fluids, cuttings piles, accidental spills, produced water and corrosion protection materials were investigated. The individual substances contained were evaluated according to their persistence, bioaccumulation and toxicity and according to a number of international and national lists of contaminants for their hazardousness to the marine environment. Since information on the use of man-made chemicals in the offshore oil- and gas industry is not available, only production water could be assessed.