Waste classification system existing chemical

The primary purpose of this Report is to present NCRP s recommendations on classification of hazardous wastes. The Report is directed at a multidisciplinary audience with different levels of technical understanding in the fields of radiation and chemical risk assessment and radioactive and chemical waste management. Anew hazardous waste classification system is proposed that differs from the existing classification systems for radioactive and hazardous chemical wastes in two fundamental respects. First, hazardous waste would be classified based on considerations of health risks to the public that arise from disposal of waste. Hazardous waste would not be classified based, for example, on its source. Second, the classification system would apply to any hazardous waste, and separate classification systems for radioactive and hazardous chemical wastes would not be retained. In the proposed system, waste would be classified based only on its properties, and the same rules would apply in classifying all hazardous wastes. 

The recommended risk-based waste classification system has important implications in three areas (1) the resulting classification of existing radioactive and hazardous chemical wastes, (2) subclassification of the basic waste classes, and (3) changes in existing laws and regulations that would be required to implement such a classification system. 

DOE s high-level wastes as if they were among the most hazardous of all radioactive wastes. However, the concentrations of hazardous substances in some of these wastes are similar to those in low-level radioactive waste that is normally intended for disposal in near-surface facilities. In contrast, some chemical wastes that are highly hazardous, compared with other wastes, and nondegradable are being sent to near-surface disposal facilities. Both of these situations occur largely because of the source-based aspects of existing waste classification systems. 

The existing waste classification systems are becoming increasingly complex as additional waste streams are incorporated into a patchwork system that is not based on a consistent set of principles. Some wastes are classified based on their source (i.e., the nature of the process or facility that produces them), some based on their composition, and some based on their physico-chemical characteristics. 

Section 4 presents detailed information on existing classification systems for radioactive and hazardous chemical wastes, the relationships between waste classification and requirements for waste disposal, and the impacts of waste classification systems on management and disposal of mixed wastes. This Section also summarizes previous NCRP recommendations relevant to waste classification. 

The discussions of classification of radioactive and hazardous chemical wastes and management of mixed waste in Sections 4.1 to 4.3 are presented in considerable detail to facilitate understanding of these issues by readers who may not be knowledgeable in these areas. The existing hazardous waste classification systems and the historical developments underlying them are complex. NCRP believes that an appreciation of these complexities is important in gaining an understanding of the need for a new hazardous waste classification system and the benefits it would provide. 

Previous sections have presented technical and historical information on radiation and chemical risk assessment and on classification of radioactive and hazardous chemical wastes. This information provides important perspectives for establishing the foundations of a new hazardous waste classification system. Before establishing these foundations, it is useful to specify the attributes that an ideal waste classification system should possess. The following sections identify the desirable attributes of a waste classification system including that the system should be risk-based, it should allow for exemption of waste, and it should be comprehensive, consistent, intrinsic, comprehensible, quantitative, compatible with existing systems, and flexible. These attributes should be recognized as goals that are not all likely to be fully realized in a practical waste classification system. 

The existing waste classification systems for radioactive and hazardous chemical wastes clearly are not comprehensive. At a fundamental level, entirely separate and quite different classification systems have been developed for the two types of hazardous waste. In addition, each classification system is not comprehensive in the context of the general type of waste to which each system applies. In the existing radioactive waste classification system, waste that arises from operations of the nuclear fuel cycle is classified separately from NARM waste. The existing classification system for hazardous chemical waste excludes many potentially important wastes that contain hazardous chemicals. 

Significant parts of the existing waste classification systems are based on intrinsic properties of waste. The system for subclassifying low-level waste in 10 CFR Part 61 (NRC, 1982a) and the determination of whether a chemical waste is characteristically hazardous (see Section 4.2.1.1) are examples of waste classification based on intrinsic properties. 

Unfortunately, however, it is difficult for anyone to fully comprehend the existing classification systems for radioactive and hazardous chemical wastes. These systems are not based on clearly stated principles from which a logical and transparent classification system might follow, and the two systems approach classification and disposal of hazardous waste in different ways. The systems intermix legal and technical considerations in ways that sometimes defy logic. A few examples of the incongruities in the waste classification systems that result in a lack of transparency and difficulties in comprehension are described below. 

Some existing waste classification systems are quantitative. For example, the concentrations of radionuclides defining the different subclasses of low-level radioactive waste that is generally acceptable for near-surface disposal are clearly stated in the regulations (NRC, 1982a), as are the quantitative conditions defining ignitable, corrosive, reactive, and toxic hazardous chemical wastes (see Section 4.2.1.1). 

A risk-based waste classification system would be established by focusing on risks that arise from disposal of hazardous wastes. Thus, the amounts of hazardous chemical wastes that would be acceptable for near-surface disposal over the longer term would need to be evaluated. While NCRP believes that many hazardous chemical wastes would continue to be acceptable for near-surface disposal, it should be anticipated that this will not be the case for some wastes that contain high concentrations of heavy metals e.g., see Okrent and Xing (1993). As a result, some hazardous chemical wastes could be classified as high-hazard (see next section), and such a classification also could also mean that perpetual institutional control will be required at some existing burial sites. 

An ideal system for classifying hazardous wastes should be risk-based, applicable to all wastes that contain radionuclides or hazardous chemicals, internally consistent, based on intrinsic waste properties, comprehensible, quantitative, and compatible with existing or feasible data and methods. To the extent that these attributes are lacking in a waste classification system, undesirable consequences are likely to result. 

Second, waste that contains hazardous substances is classified based on considerations of health risks to the public that arise from waste disposal. The existing classification systems for radioactive and chemical wastes in the United States are not based primarily on considerations of health risks to the public. Rather, classification of hazardous wastes has been based primarily on the source of the waste or the presence of particular hazardous substances. The absence of risk-based waste classifications has had a number of undesirable ramifications ... 

The objective of the study presented in this Report was to address difficulties (elaborated, for example, in Sections 1.3.1.5 and 1.4) that have arisen from use of the existing classification systems for radioactive and hazardous chemical wastes. An important impetus for... 

The existing classification systems for radioactive and hazardous chemical wastes in the United States and approaches to disposal of... 

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