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1 Introduction In 1984, more than 25 tons of methyl isocyanate was released in Bhopal, India, with devastating effects. Concern began to focus on toxic chemical release prevention and response strategies should a similar re- lease happen in the United States. The U.S. Environmental Protection Agency (EPA) in- itiated a comprehensive evaluation of the design and operating practices of the methyl isocyanate production and storage units at the one facility that manufactures the chem- ical in the United States (EPA, 1985a). In August 1985, the accidental release of aldicarb oxime and several other chemical releases from another part of that same facility received national attention and led to state legislation for improved prevention and response approaches. The Bhopal disaster and the U.S. releases underscored the paucity of data on uses and releases of toxic sub- stances and the need to obtain more and better data. Title IT} of the Superfund Amendments and Reauthorization Act (SARA) of 1986 (P.L. 99-499; 42 USC 1 1001- 1 1050) estab- lished several federal, state, and local programs to address concerns about toxic chemicals, including emergency planning, emergency notification, and community information needs; SARA also specified that EPA create a toxic release inventory. The development of Title III of SARA was affected profoundly by the right-to- know movement. Labor and environmental organizations view right-to-know laws as important to workers' and the publics un- derstanding of toxic releases as well as to the development of sound approaches for reducing occupational and community exposures. New Jersey and several local governments already had enacted or developed right-to-know laws before SARA was passed in 1986. e SARA SECTION 313 Section 313 of Title III under SARA re- quires industrial manufacturing facilities using toxic chemicals to report release infor- mation to EPA. Initial requirements for submission of this information are specified by EPA in the Toxic Chemical Release Re- porting Final Rule (Federal Register, l98Sa). The database resulting from the information reported to EPA is referred to as the Toxics Release Inventory (TRI). TRI was devised to inform the public and government officials of total routine and accidental releases to the environment of 9
10 certain chemicals from manufacturing facili- ties (Federal Register, 198Sa). Section 313(h) of SARA states that information col- lected under the TRI shall be available . . . to inform persons about releases of toxic chemicals to the environment; to assist government agencies, researchers, and other persons in the conduct of research and data gathering; to aid in the development of appropriate regulations, guidelines, and standards; and for other similar pur- poses. The initial list of toxic chemicals for TRI reporting (see Appendix A) was generated from toxic chemical lists developed by Maryland and New jersey. This list contains 308 specific chemical compounds and 20 chemical categories and can be modified only by a rulemaking, such as the deletion of titanium dioxide (Federal Register, l98Sb). The reporting requirement also applies to chemicals transported from a facility as waste for off-site treatment or disposal. Re- porting is optional for chemical quantities sent off site for recycle or reuse. A facility must report the annual releases of any of the listed chemicals it handles if the facility has the following characteristics for the specific reporting year: · Has Standard Industrial Classification (SIC) Code with the first two digits in the range from 20 through 39 (manufacturing division) (see Appendix B). · Employs 10 or more full-time workers. · Handles an annual quantity of at least one TRI-listed chemical above the following threshold amounts: 75,000 Ib/yr in 1987, 50,000 lb/yr in 1988, or 25,000 Ib/yr in 1989 and after for listed chemicals that are manufactured, imported, or processed; or 10,000 lb/yr for listed chemicals used in any other manner, such as for blending, decreasing, and coating. Definitions for "manufacture," "process," and "use" of TRI-listed chemicals are broad and wide ranging. These definitions are presented in 40 CFR 372.3 of the Com- munity Right-to-Know Final Rule as follows: M4SS BAL4NCE INFORMATION "Manufactures means to produce, prepare, import or compound a toxic chemical.... ~Process" means the preparation of a toxic chemical, after its manufacture, for distribution in commerce: (1) in the same form or physical state as, or in a different form or physical state from, that in which it was received by the person so preparing such chemical, or (2) as part of an article contain- ing the toxic chemical. "Otherwise use" or "user means any use of a toxic chemical that is not covered by the terms "manufacture" or "process" and includes use of a toxic chemical contained in a mixture or trade name product. The definition of "use" for this report (refer to Glossary) is much broader than the one given in the Community Right-to-Know Final Rule. For TRI reporting, release of a listed chemical is the discharge into the environ- ment of the chemical through such actions as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the aban- donment or discarding of barrels, containers, and other closed receptacles). Chemical manufacturing facilities that produce TRI-listed chemicals in amounts greater than the threshold are required to report the estimated chemical releases to the TRI. Similarly, facilities that use such chemicals above the threshold amount must report estimated releases. For example, a facility that produces polyvinyl chloride from vinyl chloride (a TRI-listed chemical) to manufacture PVC water pipe must report to TRI. Reporting also is required for facilities that use TRI-listed chemicals above thresh- old amounts in manufacturing processes that require no transformation of listed chemi- cals. For example, toluene is used as a sol- vent in blending surface coatings, such as paint. Toluene that is shipped into a facility as a pure solvent is shipped out of the facil
INTRODUCTION ity as the same chemical' but within a coating mixture, and must be reported to TRI. Facilities that receive TRI-listed chemi- cals present as raw material contaminants (e.g., arsenic contaminants in copper ore) or that generate byproducts during processing (e.g., cyanide as a byproduct from coking) are also required to report release estimates to the TRI, if the contaminants or byprod- ucts are present above the threshold amounts. TRI information is provided by facilities annually using EPA's Form R (see Appendix C), compiled in a computerized database, and made available to the public. The first reporting date for toxic releases in 1987 was July 1, 1988. The reported information in- cludes the following: · Facility identification. · Information on manufacturing, proces- sing, or otherwise using TRI-listed chemicals. · Data on chemical identity. · Estimated quantities of environmental releases. · Types of waste-treatment methods and efficiencies. · Information on waste minimization (optional). · Identification of all off-site locations to which TRI-listed chemicals are transferred. Facilities are not required to perform any additional monitoring or to make additional measurements for TR} reporting beyond those already obtained for other purposes. EPA provided an overview of four general methods that can be used to estimate releases subject to TRI reporting (EPA, 1987~. EPA described these approaches as follows: · Calculations based on measured concentrations of the chemical in a waste stream and the volumetric flow rate of that stream. · Mass balance around entire processes or pieces of process equipment. If input and output (i.e., product) streams are known (based on measured values), a waste stream can be calculated as the difference between input and product (accounting for accum- ulation or depletion of the chemical in the equipment). 11 · Emission factors, which usually express release as a ratio of amount released to the amount of chemical flowing through the process. (Release estimates are obtained by multiplying the emission factor by the amount of chemical flowing through the process for which estimates are needed.) Emission factors, which are commonly used for air emissions, are based on the average measured emissions at several facilities in the same industry. · Engineering calculations and/or judgment based on physical and chemical properties and relationships, such as the ideal gas law. PURPOSE OF THIS STUDY The Senate version of the bill that led to SARA required reporting mass balance in- formation in addition to information sub- mitted by each facility reporting to the TRI. SARA Section 313~1) defines mass balance as "an accumulation of the annual quantities of chemicals transported to a facility, produced at a facility, consumed at a facility, used at a facility, accumulated at a facility, released from a facility, and transported from a facility as a waste or as a commercial product or byproduct or component of a commercial product or byproduct. For the purpose of this report, this definition is con- sidered to refer to mass balance data or mass balance information. The final SARA Section 313~1) directed EPA to obtain the assistance of the National Academy of Sciences (NAS) in evaluating the value and feasibility of collecting mass balance infor- mation to meet several national information needs regarding hazardous chemicals (see Appendix D). Section 313~1~2) of SARA lists four pur- poses of the NAS study: 1. Assess accuracy of information: "To assess the value of mass balance analysis in determining the accuracy of information on toxic chemical releases" (such as data collected for the TRI). 2. Relevance to waste reduction: "To assess the value of obtaining mass balance information, or portions thereof, to deter- mine the waste-reduction efficiency of dif- ferent facilities, or categories of facilities, including the effectiveness of toxic chemical
12 regulations promulgated under laws other than this title." 3. Utility of information for chemical management: "To assess the utility of such information for evaluating toxic chemical management practices at facilities, or cate- gories of facilities, covered by this section." 4. Implications for national data develop- ment: "To determine the implications of mass balance information collection on a national scale similar to the mass balance in- formation collection carried out by the [EPA] Administrator under paragraph (3) [mass balance information collected by states], including implications of the use of such collection as part of a national annual quantity toxic chemical release program." The implications of mass balance infor- mation collection on a national scale relate not only to the three other purposes men- tioned in the charge but also to any other relevant implications of national collection. The study was designed by the Academy's National Research Council (NRC) to include an evaluation of whether additional data and analyses are needed to address adequately the issues posed for the study. If the committee determined that the potential utility of col- lecting mass balance information warranted further analysis, it would then propose a second phase of the study. The second phase would call for additional information to be gathered to test rigorously the utility of a national mass balance program. The NRC design of the study is separate from SARA Section 313~1~3), (see Appendix D), which provides that the EPA Administrator may "acquire mass balance information necessary for the study from a representative number of facilities" if currently available informa- tion "provides an inadequate representation of industry classes and categories to carry out the purposes of the study." A distinction is made between the NRC study design and Section 313~1~3), because a recommendation for a second phase would not necessarily be based upon the conditions of that section. The Committee to Evaluate Mass Balance Information for Facilities Handling Toxic Substances was convened by the NRC Board on Environmental Studies and Toxicology in November 1987. The committee comprised members with expertise in chemistry, chem- ical and environmental engineering, waste management, environmental policy, infor M4SS BALANCE INFORMATION mation management, and economics. In per- forming its charge, the committee reviewed relevant technical literature, unpublished information, and available databases. It also held a workshop in March 1988 to obtain information from other persons and organizations with special expertise (see Appendix E). Further, the committee reviewed relevant practices and experiences of state agencies with the assistance of EPA, the National Governors' Association (NGA), the New Jersey Department of Environmen- tal Protection, and the Maryland Department of the Environment. The term mass balance has been used and some would say misused by different people to mean different things. The differences usually involve the exac- titude of the data and of the data collection procedures. The committee recognized, therefore, that it should take into account differing perspectives on mass balance in addressing its charge. To most scientists and engineers, the col- lection and application of mass balance data is an exacting exercise; obtaining measured data with minimal uncertainty is emphasized. A mass balance analysis provides a rigorous accounting of toxic chemicals flowing through a manufacturing facility. The committee termed this analysis an engineer- ing mass balance (EMBJ. This type of analysis may be applied to a chemical processing unit or facility. The mass of inputs, outputs, and accumulations is determined by measurement. For each unit or for a whole facility, the masses of inputs should equal-or closely approximate- the masses of outputs plus accumulations (i.e., mass balance requires ~closuren). The masses used may be total mass, masses of individual nonreacting chemicals, or masses of individual chemical elements or combina- tions of elements. Valid application of EMB requires that measurements be made with . . prec~s~on '.e., agreement among repeated individual measurements of the same sample) and accuracy (i.e., close approximation of the actual quantities being measured). Such measurements must be made by skilled tech- nical personnel. The other school of thought about mass balance information, advocated in recent years by some policy analysts and others, argues that there is value in obtaining a more approximate level of information on chemi
INTRODUCTION cat quantities. This approach requires less resource-intensive accounting. Although proponents have called this approach a mass balance also, the committee termed it materials accounting (MA), since it is not truly a mass balance approach in the technical sense. MA relies on information that is likely to be collected routinely at a facility for business or inventory manage- ment purposes, such as records of shipments of raw materials into a facility or records of the specific amounts of chemicals in prod- ucts. MA data also can include manifest records and data required by existing environmental regulations. MA usually refers only to the flows of chemicals across facility boundaries; it does not require that all input and output data be determined (i.e., it is not focused on "closured. Examples of information used in MA are shipment records of raw materials into a facility and production records indicating the specific amounts of chemicals contained in products shipped from the facility. Analytical measurement data obtained for an EMB (e.g., gas chromatography measurements of stack emissions) could also be included as MA data. MA data are usually what is meant by proponents of nationwide collection of industrial "mass balance data." For example, at the workshop organized by the committee, representatives from EPA and various state governments described MA data to be what they meant when referring to mass balance data. An MA approach to collection of mass balance data was also described during the Senate deliberations leading to SARA. 13 Although both approaches provide simi- lar types of information, EMB is more ac- curate and precise and requires greater technical expertise and a greater level of effort than MA does. ORGANIZATION OF THIS REPORT Chapter 2 of this report reviews the EMB and MA approaches to collecting mass balance data. Experience with uses of MA information is reviewed in Chapter 3, which provides a basis for the committee's evalua- tion of the feasibility and utility of such in- formation to address the four information needs posed in SARA Section 313. Chapter 4 addresses whether the accuracy of chemical release estimates can be assessed through EMB and MA, and the usefulness of these two approaches in assessing waste re- duction efficiency is explored in Chapter 5. Chapter 6 evaluates the utility of both approaches to toxic chemical management practices, such as minimizing storage, avoid- ing catastrophic releases, and providing in- formation to the public. The implications of collecting mass balance information on a national scale are discussed in Chapter 7, as well as the potential value of such informa- tion to interested parties, including the public; policymakers; industry; and federal, state, and local governments. Chapter 7 also includes the committee's recommended approach to test a national program for toxic substances handled by industrial facilities. A glossary of terms and acronyms is presented after Chapter 7.
