Consideration of Exempt Wastes

NCRP did not undertake a detailed investigation into the kinds and quantities of radioactive or hazardous chemical wastes containing low levels of hazardous substances that might be classified as exempt, based on the consideration that allowable dispositions should pose no more than a negligible risk or dose. Rather, published studies are cited to indicate that substantial quantities of waste currently managed as radioactive or chemically hazardous waste 

NRC has issued an assessment of potential doses to the public associated with the distribution, use, and disposal of exempt products or materials containing low levels of source or byproduct material (Schneider et al., 2001) (see Section 4.1.2.5.2). In a case involving disposal of large volumes of zircon sand produced in processing of zirconium-bearing minerals, the estimated annual dose to a future on-site resident at a disposal site was 100 p.Sv, due to the elevated levels of thorium and uranium. In all other cases, however, the estimated annual dose was substantially less than 10 xSv. Since the volumes of exempt material were large in many cases, this analysis indicates that substantial volumes of waste that contains low levels of radionuclides are potentially exemptible. 

A noteworthy result of NRC s analysis of its present exemptions is that doses to individual members of the public during use of exempt products or materials generally are higher than doses that arise from disposal (Schneider et al., 2001). This is due in part to differences in the assumed exposure scenarios for use and disposal the dilution 

2 Hazardous Chemical Wastes. NCRP has not considered studies of particular wastes containing low levels of hazardous chemicals that are potential candidates for exemption. However, studies in support of proposed regulations to establish exemption levels for listed hazardous wastes (EPA, 1992d 1995c 1999c) indicate that substantial quantities of waste currently managed as chemically hazardous waste could be classified as exempt for purposes of disposal. 

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