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Natural resources that are extracted from the ground such as coal,oil,natural gas and other mineral ores contain various amounts of natural radioactivity.When these resources are extracted and processed,their natural state can be modified which may result in the enhancement of the natural radioactivity content originally present.Such enhancements may be observed in the residues or the waste created and/or in the products or by-products and are sometimes high enough to pose a risk to both humans and the environment if they are not controlled properly.Materials of this kind are commonly referred to as Naturally Occurring Radioactive Materials or NORM.Up to 1996,international regulatory attention dealing with exposure to natural sources of radiation focused mostly on exposures arising from the mining and processing of uranium ores because such activities need to be controlled as part of the nuclear fuel cycle.More recently,the attention of the international radiation protection community has been broadened to include industries dealing with NORM.Several industries operating in Brazil are dealing with NORM problems,in special,those related to tin,niobium and phosphate mining and beneficiation,and oil exploration.The Brazilian Nuclear Energy Commission has been investigating the larger ones in order assess the extent of exposure in workers and members of the public directly involved in dealing with NORM.This paper presents the characteristics of Brazilian larger NORM industries,as well as the methodologies used to evaluate the radiological impact associated to their operation.Results of the radionuclides analysis of environmental samples collected onsite these facilities demonstrate the importance of developing remediation guidelines.Finally,a briefly discussion of the Brazilian regulation,the main advances and challengers facing NORM industries is carried out.