Definition of hazard

The advantages to using MSDSs for chemical inventories are that MSDSs are publicly available and required by law. There is no extra cost or labour needed to supply them. The limitations to using MSDSs as a source of inventory data are that currently, in the United States, a standardized reporting format is not mandatory. MSDSs are not verified or audited and MSDS information can be incomplete and/or inaccurate. In addition, OSHA s definition of hazard does not include the broader scope of hazard used in green chemistry. Therefore, chemicals that are potential hazards from the green chemistry perspective but are not defined by OSHA as hazards, are not required to be identified on a MSDS. 

This chapter will introduce the entire hazardous waste identification process, but will focus particularly on the final steps and the characteristics and properties of hazardous wastes. After reading this chapter, one will be able to understand the hazardous waste identification process and the definition of hazardous waste, and be familiar with the following concepts ... 

The final steps in the hazardous waste identification process determine whether a waste poses a sufficient chemical or physical hazard to merit regulation. These steps in the hazardous waste identification process involve evaluating the waste in light of the regulatory definition of hazardous waste. The remainder of this chapter explains the definition, characteristics, and properties of hazardous wastes. 

U.S. EPA also exempts certain solid wastes from the definition of hazardous waste. If a material meets an exemption from the definition of hazardous waste, it cannot be a hazardous waste, even if the material technically meets a listing or exhibits a characteristic. There are 16 exemptions from the definition of hazardous waste ... 

Agricultural waste. To prevent overregulation of farms and promote waste recycling, solid wastes generated by crop or animal farming are excluded from the definition of hazardous waste provided that the wastes are returned to the ground as fertilizers or soil conditioners. Examples of such wastes are crop residues and manures. 

Oil, gas, and geothermal wastes. Certain wastes from the exploration and production of oil, gas, and geothermal energy are excluded from the definition of hazardous waste. These wastes include those that have been brought to the surface during oil and gas exploration and production operations, and other wastes that have come into contact with the oil and gas production stream (e.g., during removal of waters injected into the drill well to cool the drill bit). 

Mining and mineral processing wastes. Certain wastes from the mining, refining, and processing of ores and minerals are excluded from the definition of hazardous waste. 

Arsenically treated wood. Discarded arsenically treated wood or wood products that are hazardous only because they exhibit certain toxic characteristics (e.g., contain harmful concentrations of metal or pesticide constituents), are excluded from the definition of hazardous waste. Once such treated wood is used, it may be disposed of by the user (commercial or residential) without being subject to hazardous waste regulation. This exclusion is based on the fact that the use of such wood products on the land is similar to the common disposal method, which is landfilling. This exclusion applies only to end-users and not to manufacturers. 

Used oil distillation bottoms. When used oil is recycled, residues (called distillation bottoms) form at the bottom of the recycling unit. To promote the recycling of used oil and the beneficial reuse of waste materials, U.S. EPA excluded these residues from the definition of hazardous waste when the bottoms are used as ingredients in asphalt paving and roofing materials. 

Landfill leachate or gas condensate derived from listed waste. Landfill leachate and landfill gas condensate derived from previously disposed wastes that now meet the listing description of one or more of the petroleum refinery listed wastes would be regulated as a listed hazardous waste. However, U.S. EPA temporarily excluded such landfill leachate and gas condensate from the definition of hazardous waste provided their discharge is regulated under the CWA. The exclusion will remain effective while U.S. EPA studies how the landfill leachate and landfill gas condensate are currently managed, and the effect of future CWA effluent limitation guidelines for landfill wastewaters. 

When U.S. EPA has a cause to believe for some other reason, the waste typically fits within the statutory definition of hazardous waste developed by Congress. 

The hazardous waste listings, the hazardous waste characteristics, and the mixture and derived-from rules are all essential parts of the definition of hazardous waste, but these key elements are all described in different sections of the RCRA regulations. Only one regulatory section unites all four elements to establish the formal definition of hazardous waste. This section is entitled Definition of Hazardous Waste, which states that all solid wastes exhibiting one of the four hazardous characteristics are hazardous wastes. This section also states that all solid wastes listed on one of the four hazardous waste lists are hazardous wastes. Finally, this section explains in detail the mixture and derived-from rules and the regulatory exemptions from these rules. Thus, although the section is entitled Definition of Hazardous Waste, it serves primarily as a guide to the mixture and derived-from rules. 

On April 8, 2003, U.S. EPA proposed to add benzene and 2-ethoxyethanol to the list of solvents whose mixtures with wastewater are exempted from the definition of hazardous waste.23 U.S. EPA is proposing to provide flexibility in the way compliance with the rule is determined by adding the option of directly measuring solvent chemical levels at the headworks of the wastewater treatment system. In addition, U.S. EPA is proposing to include scrubber waters derived from the combustion of spent solvents to the headworks exemption. Finally, U.S. EPA is finalizing the Headworks Rule, as follows24 ... 

Benzoyl peroxide as a pure solid is classified as a deflagration hazard. When it is a solid containing about 30% water it is an intermediate fire hazard. As a paste (50% peroxide) it is a low fire or negligible hazard. See reference 18 for a definition of hazard classifications. Benzoyl peroxide containing 50% water will be purchased. It should be stored in a separate cool area, since all peroxides have short half-lives. 

Identification and Listing of Hazardous Waste Definition of hazardous waste-generic exclusion levels for K061 and K062 nonwastewater HTMR residues 0.15 mg/L (maximum for any single composite sample TCLP 40 CFR 261.3 EPA 1992... 

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) gives a broader definition of hazardous substances, which includes the following ... 

Pesticides are very much a part of the definition of hazardous wastes (Table 11). In fact, the toxicity characteristic of hazardous waste as defined by RCRA (referred to as extraction procedure or EP toxicity) is based on threshold concentrations of eight metals and six pesticides in an extract of the waste (Table II-A). Sixteen of the specific hazardous waste streams listed by... 

The system for classification and disposal of hazardous chemical waste developed by EPA under RCRA does not apply to all wastes that contain hazardous chemicals. For example, wastes that contain dioxins, polychlorinated biphenyls (PCBs), or asbestos are regulated under the Toxic Substances Control Act (TSCA). In addition, the current definition of hazardous waste in 40 CFR Part 261 specifically excludes many wastes that contain hazardous chemicals from regulation under RCRA, including certain wastes produced by extraction, beneficiation, and processing of various ores and minerals or exploration, development, and use of energy resources. Thus, the waste classification system is not comprehensive, because many potentially important wastes that contain hazardous chemicals are excluded, and it is not based primarily on considerations of risks posed by wastes, because the exclusions are based on the source of the waste rather than the potential risk. 

Based on the legal definition of hazardous waste given above, EPA developed a definition of hazardous chemical waste in 40 CFR Part 261 (EPA, 1980b). Hazardous chemical waste is defined as a... 

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