United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5305)
EPA530-R-94-015
July 1994
Setting Priorities for
Hazardous Waste
Minimization
Recycled/Recyclable
Printed on recycled paper that contains at
least 50% post-consumer recycled fiber
-------
-------
ACKNOWLEDGEMENTS
This document was developed by USEPA's Office of Solid Waste (OSW). Mark Ralston
of OSW's Waste Minimization Branch was the Work Assignment Manager. ICF Incorporated
assisted OSW in the development of this document in fulfillment of Contract No. 68-W2-0008,
Work Assignment 61.
-------
-------
TABLE OF CONTENTS
Page
EXECUTIVE SUMMARY ES-1
E.S.1 Introduction ES-1
E.S.1.1 Waste Minimization and Combustion Strategy ES-1
E.S.1.2 Draft RCRA Waste Minimization National Plan ES-2
E.S.1.3 Review Process ES-2
E.S.2 Methodology ES-4
E.S.2.1 Methodology for Identifying Combusted Hazardous Wastes
Containing Metals and/or Halogenated Organics ES-4
E.S.2.2 Methodology for Prioritizing Wastestreams and Industrial
Processes ES-5
E.S.3 Draft Results ES-7
E.S.3.1 Draft Results: Combusted Hazardous Wastes Containing
Metals and/or Halogenated Organics , ES-7
E.S.3.2 Draft Results: Prioritization of Wastestreams and Industrial
Processes ES-9
E.S.4 Limitations ES-11
CHAPTER 1 INTRODUCTION 1-1
1.1 Overview of Waste Minimization and Combustion Strategy and Draft
RCRA Waste Minimization National Plan 1-1
1.1.1 Waste Minimization and Combustion Strategy 1-1
1.1.2 Draft RCRA Waste Minimization National Plan 1-2
1.2 Review Process for Draft Prioritization Methodology and Results and
Submission of Comments 1-3
1.2.1 Review Process 1-3
1.2.2 Submission of Comments 1-5
1.3 Organization of Document 1-5
CHAPTER 2 IDENTIFYING COMBUSTED HAZARDOUS WASTES CONTAINING
METALS AND HALOGENATED ORGANICS 2-1
2.1 METHODOLOGY 2-1
2.1.1 Biennial Reporting System (BRS) Data Structure 2-1
2.1.2 Identifying Combusted Wastes and Their Origins 2-4
2.1.3 Identifying Constituents and Concentrations 2-6
2.2 DRAFT RESULTS 2-12
2.2.1 Overview of Combusted Wastes 2-12
2.2.2 Characteristics and Origins of Routinely Generated, Primary
Combusted Wastes 2-12
2.2.3 Characteristics of the Top 100 Combusted Wastestreams Containing
Metals and/or Halogenated Organics 2-18
2.3 LIMITATIONS 2-26
-------
TABLE OF CONTENTS (continued)
Page
CHAPTER 3 PRIORITIZING WASTESTREAMS AND THE INDUSTRIAL
PROCESSES GENERATING THEM 3.!
3.1 METHODOLOGY .'.'.'.'.'.'.".'.'.'.'.' 3-1
3.1.1 Considerations Relevant to the Prioritization System 3-1
3.1.2 Balancing the Considerations 3_2
3.1.3 Review of Existing Screening, Ranking, and Prioritization Systems ... 3-4
3.1.4 Prioritization System Developed Based on the HRS 3-5
3.2 DRAFT RESULTS '.'.'.'.'.'. ' 3-10
3.2.1 Scores and Ranks for Wastestream Combinations 3-10
3.2.2 Scores and Ranks Based on Waste Origins 3-18
3.2.3 Summary 3_jg
3.3 LIMITATIONS ..........!......'...' 3-24
APPENDICES (Bound separately)
Appendix 1. Sample BRS Data Forms
Appendix 2. BRS Code Descriptions
Appendix 3. Matching Process - WR/GM
Appendix 4. Documents Used as Sources of Concentration Data
Appendix 5. Retrieval from GENSUR
Appendix 6. Waste Characterizations for Top 150 Routinely Generated Combusted Waste
Stream Combinations
Appendix 7. Summary of Prioritization Systems
Appendix 8. HRS Hazard Data and Pathway Scores from Superfund Chemical Data Matrix
Appendix 9. States and Regions in Which Top 100 Ranked Wastestream Combinations are Generated
-------
EXECUTIVE SUMMARY
The purpose of this draft methodology document is two-fold: (1) to describe the work
that the U.S. Environmental Protection Agency (EPA) has conducted to date in developing a
methodology to set priorities in determining which combusted hazardous wastes EPA, States,
industry, and other stakeholder groups should focus on regarding waste minimization, and (2) to
present draft prioritization results.
Section E.S.1 provides the context for EPA's work on setting priorities for minimization of
hazardous wastes and describes the review process for the draft methodology document. Section
E.S.2 summarizes the Agency's methodology for identifying combusted hazardous wastes
containing metals and/or halogenated organics and then presents the hazard-based methodology
used to rank hazardous wastestreams and industrial processes. Section E.S.3 presents draft
results. Finally, Section E.S.4 presents limitations of the analysis.
E.S.1 Introduction
E.S.1.1
Waste Minimization and Combustion Strategy
Although the Agency has devoted significant effort to evaluation and promotion of waste
minimization in the past,1 the Hazardous Waste Minimization and Combustion Draft Strategy2
recently provided a significant impetus to this effort. The Draft Strategy had several components,
among which was reducing the amount of hazardous waste generated in the United States. Other
components of the Draft Strategy included strengthening controls on emissions from combustion
units; enhancing public participation in facility permitting; conducting risk assessments as part of
permitting; and enforcing regulatory and permit requirements.
Among the Draft Strategy's primary goals were establishing a strong preference for source
reduction over waste management, and better addressing public participation in setting a national
source reduction agenda.3 In promoting waste minimization, the Agency will focus primarily on
promoting source reduction for hazardous wastes and will promote environmentally sound
recycling only where source reduction is not feasible.
To facilitate public dialogue on both waste minimization and combustion, EPA held a
National Roundtable during November 1993 and a series of Regional Roundtables during the
spring of 1994. At these Roundtables, public interest groups, citizens, industry, State and Federal
regulators, and technical experts in pollution prevention were invited to discuss a broad range of
1 For example, EPA prepared a report to Congress, Minimization of Hazardous Wastes (October
1986), that summarized existing waste minimization activities and evaluated options for promoting waste
minimization.
2 U.S. EPA, May 1993.
3 The Hazardous and Solid Waste Amendments (1984) to the Resource, Conservation, and Recovery
Act (RCRA) together with the Pollution Prevention Act of 1990 identified a hierarchy of waste
management options where reduction at the source was the preferred option, followed in turn by
environmentally sound recycling, treatment, and finally disposal.
ES-1
-------
issues. The messages heard at the Roundtables are the building blocks for EPA's efforts to
promote source reduction and recycling. These messages included: setting priorities based on risk;
adopting a multi-media approach, considering risks via all media; focusing on persistent, toxic,
bioaccumulative constituents in wastestreams; and encouraging movement up the waste
management hierarchy.
E.S.1.2
Draft RCRA Waste Minimization National Plan
The Draft RCRA Waste Minimization National Plan (RWMNP)4 is divided into two
phases. Phase I of the RWMNP is the primary vehicle for promoting source reduction and
recycling under the Waste Minimization and Combustion Strategy. Phase II of the RWMNP will
then move beyond wastes managed in combustion units to promote source reduction and recycling
for wastes managed by other practices, applying the messages heard and lessons learned during
Phase I. As shown in Exhibit 1-1, the process of setting priorities is one of the building blocks for
the RWMNP.
E.S.L3
Review Process
The messages heard from stakeholder groups at the National and Regional Roundtables
formed the foundation for development of the RWMNP and the prioritization methodology.
Informal guidance on prioritization methodology development was provided by staff from a variety
of Agency program offices during review of potential methodologies and development of
wastestream data. The Agency also discussed comments on the RWMNP and prioritization
methodology with representatives of some stakeholder groups (e.g., States and industry trade
associations). Finally, EPA briefed the Science Advisory Board on the methodology and received
some comments during a brief, informal consultation in June 1994.
The Agency plans to solicit and respond to comments on the prioritization methodology
and results in several ways prior to Onalizing Phase I of the RWMNP. The Agency will review
and summarize the public comments provided both on the RWMNP and on this methodology
document. The Agency will also be establishing a formal Agency workgroup to develop the final
Phase I RWMNP, and one of the subcommittees on the workgroup will focus on reviewing and
revising the prioritization methodology based on both internal EPA and stakeholder group
comments. In addition, a focus group meeting is planned for September 1994 to formally obtain
comment from stakeholder groups on the Draft RWMNP; part of this meeting will serve as a
forum to obtain comment on details of the prioritization methodology.
E.S.2 Methodology
E.S.2.1 Methodology for Identifying Combusted Hazardous Wastes Containing
Metals and/or Halogenated Organics
To characterize the universe of combusted hazardous wastes, EPA employed 1991 data
from the Biennial Reporting System (BRS), the most comprehensive national data available in
4 U.S. EPA, May 23, 1994.
ES-2
-------
Exhibit 1-1.
Summary of the Key Components of the
Draft RCRA Waste Minimization National Plan
ESTABLISH GOALS
Reduce quantity and toxicity of hazardous waste through source reduction and then recycling
' ' I
________ _^^^^^-^^^--.^^^^-^^^^.^^^^^^^^^^^f^^^^^^^^^^^^^^mm^m^*mm^^mfmm^^^l^f^^l^f^mfm^m^mttf^mtti^if^^^^^i>^^^-^^^^
SET PRIORITIES FOR SOURCE REDUCTION AND RECYCLING
Rank wastestreams based on multi-media hazard and exposure potential, then
Rank industrial processes based on hazard of wastestreams they generate
Select priorities among industrial sectors, processes, wastestreams, and/or constituents
_ I _ _ _ _
IDENTIFY/EVALUATE SOURCE REDUCTION AND RECYCLING OPPORTUNITIES
With the ultimate goal of optimizing source reduction above other methods, when feasible.
Consider:
Technical and economic feasibility
Economic impacts
Cross-media transfers '
ARRAY MECHANISMS FOR EFFECTING SOURCE REDUCTION AND RECYCLING
Non-regulatory vs. regulatory mechanisms.
Consider:
« Other EPA initiatives that are relevant
Which option(s) will result in the greatest environmental benefits
Resource constraints for effective outreach/implementation
_ Our sphere of influence _ _ ___ _
1
IMPLEMENT MECHANISMS
Employ regulatory development, guidance, permitting, voluntary challenge programs, and
coordinate with Regions, States, technical assistance centers to both implement and develop
measures of success.
i
MEASURE PROGRESS BEING MADE
ES-3
-------
early 1994 on the generation and management of hazardous wastes in the United States.5 EPA
first estimated the quantities of hazardous wastes managed by combustion facilities (i.e.,
incinerators and burners and industrial furnaces (BIFs)). To focus on those combusted wastes
affording the best initial opportunities for source reduction and recycling, EPA excluded
combusted wastes that are not routinely generated (i.e., wastes from remediation, spill cleanup,
and equipment decommissioning). "Secondary" hazardous wastes (i.e., residuals from treatment,
disposal, and/or recycling of hazardous wastes) were also excluded, to avoid double counting
between the hazardous wastes that were treated/disposed/recycled and their residuals.
Once the universe of combusted wastes had been identified, the BRS was used to
determine the origins of these wastes (i.e., the industrial sectors and processes generating the
wastes). The Agency is particularly interested in determining the origins of combusted wastes,
since this information forms the foundation of later efforts in the RWMNP to identify, evaluate,
and promote source reduction and recycling alternatives. Tracing the origins of wastes received'at
off-site combustion facilities proved to be particularly difficult, because it involved linking data
from BRS reporting forms filed by the generators of wastes with corresponding data from forms
filed separately by the combustion facilities receiving those wastes. Several specific factors made
it difficult to link generation to off-site combustion:
In many cases, the BRS records are missing facility identification numbers or other
key data needed to make the link between generating and receiving facilities.
Generating facilities tend to report quantities on an annual basis, whereas the
receiving facilities often report quantities on the basis of the amount in individual
shipments, and thus quantities often do not match well.
Some of these wastes have a complex path from "cradle" to "grave." Much of the
waste that is ultimately burned off site is first collected and commingled at
intermediary facilities (such as fuel blenders) prior to combustion.
EPA was able to identify the origin of about 40 percent of the wastes managed off-site.
The Agency also used the BRS data as a starting point in assessing waste characteristics,
since the BRS included information on the form of the waste (e.g., inorganic liquid or organic
sludge) and, in some cases, on the constituents (i.e., chemicals) present in the waste that were
reported under the Toxics Release Inventory. However, two of the most important data elements
in assessing the potential hazard associated with wastestreams also are among the most difficult to
characterize: the constituents present in the waste and their concentrations.**
The Agency recognizes that there have been some significant changes in waste generation and
management since 1991. Nevertheless, the 1991 BRS data provide a useful and comprehensive basis for
characterizing combusted hazardous wastes.
These data elements are also important in measuring progress being made in minimizing hazardous
wastes. Waste quantity provides only a partial picture of progress, since the concentrations and toxicities
of constituents could increase at the same time that waste quantity decreased. (It should be noted that
other factors are also important in measuring progress, such as economic conditions.)
ES-4
-------
EPA devoted significant effort to identifying constituents in combusted hazardous
wastestreams and estimating approximate constituent concentrations. The Agency focused in
particular on wastestreams containing metals and/or halogenated organics. Although the
characterization effort was limited to wastestreams containing metals and/or halogens, the Agency
identified other constituents (i.e., constituents that were not metals or halogens) also present in
these wastestreams. To facilitate waste characterization, EPA grouped combusted wastestreams
that were identical in terms of four key attributes: RCRA hazardous waste codes, industrial sector
of the generator (i.e., based on the four-digit Standard Industrial Classification code), waste
source, and waste form. The top 100 of these "wastestream combinations," in terms of quantity,
were characterized; these top 100 wastestream combinations account for approximately 50 percent
of all combusted wastestreams. In order to assess how representative these top 100 combinations
are of the entire universe of combusted wastes, EPA compared the top 100 combinations with all
remaining combusted wastestreams in terms of predominant waste forms, management locations,
quantities, and other characteristics.
In characterizing the top 100 wastestream combinations, EPA assembled the best data that
were readily available (e.g., data from technical background documents for hazardous waste
listings and best demonstrated available technology (BDAT) determinations, and the 1986
Generator Survey). Not all information sources were available for each wastestream combination,
so EPA had to apply judgement on when to use the sources and when to make assumptions to
bridge data gaps.
E.S.2.2 Methodology for Prioritizing Wastestreams and Industrial Processes
A number of different EPA and State ranking methodologies were reviewed and evaluated
against a set of key EPA considerations, in order to assess their applicability to scoring hazardous
wastes. These considerations included:
applicability to the goal of the RWMNP to reduce the quantity and toxicity of
hazardous waste (indicating an approach focusing on the hazard of the wastes as
generated (i.e., prior to management));
consistency with the focus of Phase I of the RWMNP on combusted hazardous
wastestreams (indicating an approach focusing on the hazard of wastes as
managed);
consistency with messages heard during the November 1993 Roundtable;
ability to be quickly implemented with readily-available data;
level of peer review; and
appropriateness for national screening purposes and adaptability for Regional or
State use based on their priorities.
The Agency attempted to balance these sometimes competing considerations in developing
a national screening methodology that would serve as a first step in setting priorities for waste
minimization. In reviewing potentially-applicable prioritization methodologies, the Agency
ES-5
-------
focused first on approaches that would rank wastes based on their hazard as generated, in keeping
with the broad goal o' the RWMNP to reduce the quantity and toxicity of hazardous wastes. In
examining the hazarc wastes as generated, the Agency's objective was to identify and promote
source reduction for ;-.isles that are the most pervasive, toxic, mobile, persistent, and/or
bioaccumulative, considering the major environmental pathways of contaminant transport and
exposure (air, surface water, ground water, soils, and the foodchain). This approach would
potentially reduce not only the generation of hazardous wastes, but the release of toxic
constituents tp all media and the subsequent exposures of workers, the general public, and the
environment.
A secondary consideration in developing EPA's system for prioritizing wastes was to
identify wastes that would potentially pose the greatest risks when burned in combustion units, in
keeping with the focus of Phase I of the RWMNP on combusted hazardous wastes. EPA did not
attempt to actually estimate releases, exposures, and risk/hazard from combustion units (i.e.,
risk/hazard from wastes as managed) for the purpose of ranking wastestreams due to: the
significant data requirements and apparent lack of screening methodologies to do this; the
ambitious schedule for Phase I of the RWMNP: and the fact that Regions and/or States would
potentially be better able and more suited to conduct these analyses. Instead, the Agency decided
to focus on the characteristics of combusted wastestreams, focusing in particular on wastestreams
containing metals and/or halogenated organic compounds. :
j ' *
A number of participants at the National Roundtable expressed "particular concern about
combustion of wastes containing metals and halogenated organic compounds. Metals are a
concern since they are not destroyed during combustion and typically end up in ash, releases to
air, and/or products (e.g., cement). All metals are persistent, and some are toxic and/or
bioaccumulative. Some metals (e.g., copper) are also believed to act as catalysts in the synthesis
of dioxins during combustion. Halogenated organic compounds are a concern since they may
contribute to formation of dioxins during combustion. Aside from the potential for reduced risks
from combustion, there may be other multimedia benefits from reducing generation of
halogenated organic-containing wastestreams, since some halogenated compounds have been
associated with depletion of stratospheric ozone and others have been linked with special ground
water remediation problems. Furthermore, some halogenated organics do not degrade readily in
the environment and tend to exhibit high human and ecological toxicities. Halogenated organics
are also prominent on lists of "persistent bioaccumulators" that have been derived for various
prioritization purposes.
Based on these and other considerations, the Agency selected a methodology relying
primarily on a set of modified waste characteristics scoring algorithms from the Superfund Hazard
Ranking System (HRS). Among the advantages of this methodology are the following: it includes
a number of hazard-related prioritization criteria (i.e^, waste quantity, constituent concentration,
human and ecological toxicity, mobility, persistence, and bioaccumulation potential) and considers
four primary pathways of potential contaminant transport and exposure (i.e., air, surface water,
ground water, and soils); it could be quickly implemented with limited modification and with
readily-available data; and it has been extensively peer-reviewed.
The basic steps involved in scoring and ranking a given wastestream include: (1) estimating
the mass of each constituent in the wastestream by multiplying waste volume times constituent
ES-6
-------
concentration; (2) selecting the highest pathway score7 for each constituent, reflecting the
pathway by which the constituent presents the greatest hazard; (3) calculating the constituent
hazard score for each constituent by multiplying constituent mass times pathway score; and (4)
selecting the highest among the constituent hazard scores to represent the wastestream score.
The methodology was used to score the top 100 wastestream combinations identified
earlier. Wastestream scores were then used to rank industrial processes (i.e., sources) by
apportioning each wastestream score among the industrial processes generating it on a quantity
basis.
E.S3 Draft Results
E.S .3.1 Draft Results: Combusted Hazardous Wastes Containing Metals and/or
Halogenated Organics
ft . '' ' . ' ,
Overview of Combusted Wastes
f?_ *
In 1991, approximately 310 million tons of hazardous waste was reported in the BRS to be
managed in units subject to RCRA requirements. Of this amount, approximately 3.6 million tons
(or 1.2 percent) was managed by combustion. To focus on combusted wastes affording the best
initial opportunities for source reduction and recycling, EPA excluded non-routinely-generated
wastes and secondary wastes, leaving about 3.0 million tons of combusted waste for further
analysis. Approximately two thirds of this total was combusted at on-site facilities, while the
remaining third was sent off site for combustion at commercial or non-commercial facilities.
Characteristics and Origins of Combusted Wastes
Of the 3.0 million tons of routinely-generated primary hazardous waste combusted in 1991,
approximately 55 percent was managed in incinerators and 45 percent in BIFs. The bulk of this
quantity was liquids: approximately half was classified as organic liquid and one-fourth as inorganic
liquid. Sludges and solids accounted for one eighth of the quantity, and the remainder was of
unknown form.
Three specific source categories contributed over 50 percent of the combusted waste
quantity: product distillation (23 percent), spent process liquids removal (17 percent), and by-
product processing (11 percent). For 28 percent of the quantity, the source could not be
identified.
Although close to 400 industries (as defined by 4-digit SIC code) generated wastes
destined for combustion in 1991, much of the quantity was concentrated in a few sectors. These
sectors included: industrial organic chemicals (SIC 2869) with 40 percent of the quantity,
pesticides and agricultural chemicals (SIC 2879) with 9 percent, and plastic materials and resins
(SIC 2821) with 6 percent.
7 The pathway score corresponds to the taxicity/combined factor value in the HRS.
ES-7
-------
Combustion facilities in EPA Region 6 generated and managed close to 50 percent of
combusted wastes in 1991. Regions 7, 5, and 2 each had approximately 10 percent of the
quantity. Among states, Texas generated and managed about 40 percent of the combusted waste,
followed by Missouri, Louisiana, Indiana and New Jersey, each with less than 10 percent.
Characteristics and Origins of Top 100 Wastestream Combinations
As discussed above, EPA determined which constituents were present in large-volume
"wastestream combinations" and identified the top 100 of these combinations containing metals
and/or halogenated organics. These top 100 combinations, representing approximately 50 percent
of routinely-generated primary combusted wastes, were used as the basis for setting priorities for
hazardous waste minimization.
The Agency characterized the top 100 wastestream combinations in a number of ways. In
addition, EPA compared them with the remaining 18,922 wastestream combinations, to assess how
representative the top 100 combinations were of combusted hazardous wastes generally.
The predominant waste forms, both among the top 100 wastestream combinations and for
the remaining set, were organic liquids (47 percent and 54 percent, respectively) and inorganic
liquids (35 percent and 14 percent, respectively). Waste form was not reported (or had an invalid
entry) for about 5 percent of the top 100 combinations, and almost 20 percent of the remaining
wastes.
«'
On-site management was more common for the top 100 wastestream combinations than
for the remaining wastestreams. Approximately 75 percent of the top 100 were managed on site,
whereas 57 percent of the remaining wastestreams were managed on site. This finding comports
with the fact that the top 100 combinations represent much larger waste quantities, on average,
than the remaining wastestreams. In general, the larger the wastestream, the more likely it is to
be managed on site due to economies of scale in waste management.
For the top 100 wastestream combinations, two-thirds of the 1.1 million tons managed on
site in 1991 was managed in incinerators (with the rest managed in BIFs), while for the 380
thousand tons managed off site, less than 10 percent was managed in incinerators. Commercial
facilities managed about two-thirds of the 380 thousand tons that went off site; BIFs accounted
for most of this commercial management.
Two industry groups generated 52 percent of the waste in the top 100 wastestream
combinations: industrial organic chemicals (SIC 2869) with 37 percent and agricultural chemicals
(SIC 2879) with 15 percent. No other industry accounted for more than 7 percent of the
quantity. A similar pattern emerged for the remaining wastestreams, where industrial organic
chemicals generated 38 percent, agricultural chemicals generated 4 percent, and no other industry
generated a significant portion of the quantity.
The sources of wastes were nearly identical for the top 100 wastestream combinations and
for the remaining wastestreams. In both cases, the source generating the largest quantity was
product distillation, followed by spent process liquids removal and by-product processing.
ES-8
-------
EPA has considerable experience in developing waste minimization strategies for
routinely-generated wastes where the source is -a well-defined, integral part of the production
process. However, there are several categories of wastes among the top 100 wastestream
combinations that are not well-defined (e.g., due to missing data) or where sources are not part of
production processes (e.g., pollution control devices). These wastes, which represent about 35
percent of the total quantity for the top 100 combinations, would require further study (and
potentially a better understanding of "upstream" processes) in order to evaluate waste
minimization opportunities. These waste types include: process blank, unknown, or "other" (24
percent of total quantity); still bottoms (6 percent); and wastes from waste treatment and "other"
pollution control (5 percent).
E.S.3.2 Draft Results: Prioritization of Wastestreams and Industrial Processes
EPA presents the draft results from the scoring and ranking analysis first in terms of
wastestream combinations, and then aggregated based on origins of the wastes. Note that the
numeric hazard scores do not correspond to any absolute measure of the magnitude of hazard or
risk; only the relative difference between the wastestream combination scores is significant.
The range of scores for each of the top 100 wastestream combinations is quite broad, from
about 5.1E+06 to 7.1E+13,8 and the total hazard score (summed across all wastestream
combinations) is 1.9E+14. The draft results indicated that:
(1) Most of the hazard - almost 85 percent of the total hazard score - is accounted
for by the top five wastestream combinations. Three of these five wastestream
combinations belong to SIC 2869 (Industrial Organic Chemicals) and Source Code
A33 (Product Distillation);
(2) Although there is a very large range in the scores (almost seven orders of
magnitude), 73 of the 100 fall within a two order of magnitude range, between
1E+10 to 1E+12. Thus, as measured by the scoring system, there is a fairly large
set of. wastes with a similar degree of hazard, and smaller sets of relatively high-
hazard and low-hazard wastes that are distinctly different;
(3) The hazard of a given wastestream combination is not driven by waste quantity
alone, but reflects both the waste quantity and the hazard of the waste
constituents. The components of the scoring system driven by constituent
properties (e.g., toxicity, persistence, bioaccumulation potential) appear to be at
least as important as waste quantity in determining the score.
The scores for the individual wastestream combinations can be summed across factors they
have in common, i.e., waste form, source of the waste, and SIC of the generator. The results
discussed below, which indicate trends in total hazard potential, compare the sum of hazard scores
for a given factor to the total hazard score summed across all wastestream combinations.
8 For scientific notation, this report uses a convention used frequently in computer programming, i.e.,
the digits following a capital E represent the exponent to the power of 10. For example, 2E+02
represents 2 x 102, or 200.
ES-9
-------
Three waste forms - "other" organic liquids, concentrated aqueous solutions of other
organics, and resins - comprise almost 92 percent of the total hazard score (primarily because
they are associated with the top five wastestream combinations). Non-halogenated and
halogenated solvents comprise most of the remaining share of the total hazard score.
EPA also summed the hazard scores across all of the SIC/source combinations. About 85
percent of the total hazard score is contributed by three combinations:
SIC Code 2869 (Industrial Organic Chemicals)/Source Code A33 (Product
Distillation);
SIC Code 2833 (Medicinal Chemicals and Botanical Products)/Source Code A32
(Product Filtering); and
Non-classifiable SIC Code/Unspecified Source Code.
These constitute the combinations representing the top five wastestream combinations. The next
combination, unknown SIC and unknown source, primarily comprises non-halogenated solvents
(the seventh ranked wastestream combination) and waste oils (the tenth ranked wastestream
combination).
Most of the ten top-ranked wastestream combinations represent a small number of BRS
records of wastestreams at a few facilities, as shown below.
Wastestream
Combination
Rank
No. of BRS
Records of
Wastestreams
No. of Facilities
Place of
Management
Region
State
1
H^BH
3
1
on-
site
VI
TX
2
1
1
on-
site
I
CT
3
m^^Hi
^^H
1
1
on-
site
m
PA
4
^_____
{^M
2
1
on-
site
VI
TX
5
MM^^H
MI^HI
1
1
off-
site
V
IN
6
«^^___
2
1
on-
site
VI
TX
7
12
12
off-site
uun
CT,MA,
NJ,NY,
PA.VA,
WV
8
1
1
on-
site
IV
KY
9
1
1
on-
site
ra
VA
10
450
450
both
many
many
The nine top-ranking wastestream combinations are focused in 20 or fewer facilities; slightly less
than half of these facilities manage their wastes on site. This indicates that for the nine highest-
hazard wastestream combinations, there is an opportunity to focus the next phase of the
prioritization and waste minimization effort within a relatively small set of facilities. This may
ES-10
-------
allow for site-specific data collection and evaluation of waste minimization potential. The tenth-
ranked wastestream combination, waste oils, is generated by a much larger set of facilities, many
of whom ship wastes off-site.
The draft results indicate that a majority of the nine top-ranking wastestream
combinations are focused primarily in the States of Texas, Connecticut, Pennsylvania, and
Virginia Three of these states account for a large percentage of the total hazard score across all
wastestream combinations, i.e., Texas (* 53 percent), Connecticut (* 20 percent), and
Pennsylvania (= 13 percent).
E.S.4 Limitations
The results described in this report are subject to a number of important limitations. The
Agency emphasizes that the draft results must be viewed in the context of these limitations. The
concluding sections of Chapters 2 and 3 describe them; a brief summary follows.
Limitations in Identifying and Characterizing Combusted Wastes
The most recent comprehensive data available on waste generation and
management are from 1991.
Data used in this analysis do not reflect recent State updates.
Data were missing for some key data fields in the BRS.
Constituent content and concentration estimates are rough approximations.
The Generator Survey and other sources used to characterize wastes may not be
current.
Generator Survey data are likely to be more accurate for metals than for organics.
Limitations in Prioritizing Wastestreams and the Industrial Processes Generating Them
Hazard scores are subject to the uncertainty in the underlying waste
characterization/constituent concentration data.
The method incorporates assumptions and limitations of the HRS.
The approach does not account for hazards related to corrosive and
ignitable/flammable nature of some hazardous wastestreams.
The method does not directly address releases and exposures, particularly post-
combustion releases and exposures.
The method does not correspond directly to a measure of "absolute" risk.
ES-11
-------
As a practical matter, any method that seeks to simulate complex environmental processes,
but is founded on simple scoring algorithms and uncertain data, will always carry with it important'
limitations. Some of these limitations may become less constraining as the approach is refined
and improved. The Agency looks forward to receiving comments on the proposed approach for
setting priorities for waste minimization, and will carefully consider all information it receives.
ES-12
-------
CHAPTER 1
INTRODUCTION
The purpose of this draft methodology document is two-fold: (1) to describe the work that
the U.S. Environmental Protection Agency (EPA) has conducted to date in developing a
methodology to set priorities in determining which combusted hazardous wastes EPA, States,
industry, and other stakeholder groups should focus on regarding waste minimization, and (2) to
present draft prioritization results.
This chapter provides the context for EPA's work on setting priorities for minimization of
hazardous wastestreams. Section 1.1 provides an overview of the Hazardous Waste Minimization
and Combustion Draft Strategy and the related Draft RCRA Waste Minimization National Plan,
which provided the impetus for development of the prioritization system. Section 1.2 discusses
the review process for the draft prioritization methodology and results. Finally, Section 1.3
provides an overview of the remaining chapters and appendices.
11 OVERVIEW OF HAZARDOUS WASTE MINIM NATION AND COMBUSTION DRAFT
STRATEGY AND DRAFT RCRA WASTE MINIMIZATION NATIONAL PLAN
1.1.1 Waste Minimization and Combustion Strategy
Although the Agency has devoted significant effort to evaluation and promotion of waste
minimization in the past,1 the Hazardous Waste Minimization and Combustion Draft Strategy2
(referred to throughout this document as the "Draft Strategy") recently provided a significant
impetus to this effort. The Draft Strategy was designed, among other things, to reduce the
amount of hazardous waste generated in the United States. Other components of the Draft
Strategy included: strengthening federal controls governing hazardous waste incinerators and
boilers and industrial furnaces (BIFs); enhancing public participation at the time of and prior to
permitting a facility; conducting full risk assessments at each combustion facility to be permitted
and taking that assessment into consideration at the time of permitting; and ensuring that
regulatory and permit requirements are vigorously enforced.
Among the Draft Strategy's primary goals were establishing a strong preference for source
reduction over waste management and better addressing public participation in setting a national
source reduction agenda.3 In promoting waste minimization, the Agency will focus primarily on
promoting source reduction for hazardous wastes and promote environmentally sound recycling
only where source reduction is not feasible.
1 For example, EPA prepared a report to Congress, Minimization of Hazardous Wastes (October
1986), that summarized existing waste minimization activities and evaluated options for promoting waste
minimization.
2 U.S. EPA, May 1993.
3 The Hazardous and Solid Waste Amendments (1984) to the Resource, Conservation, and Recovery
Act (RCRA) together with the Pollution Prevention Act of 1990 identified a hierarchy of waste
management options where reduction at the source was the preferred option, followed in turn by
environmentally sound recycling, treatment, and finally disposal.
1-1
-------
To facilitate public dialogue on both waste minimization and combustion, EPA held a
National Roundtable during November 1993 and a series of Regional Roundtables during the
spring of 1994. At these Roundtables, public interest groups, citizens, industry, State and Federal
regulators, and technical experts in pollution prevention were invited to discuss a broad range of
issues. Some key messages related to waste minimization that came out of these Roundtable
discussions included:
Emphasize the multi-media aspects of pollution prevention. Focus on pollution
prevention in all aspects of waste management, and assure that we really get
source reduction, rather than a shifting of. pollutants from one environmental
media to another.
Reinforce the waste management hierarchy that has been stated in RCRA, the
Pollution Prevention Act, and reiterated in Administrator Browner's memo on
EPA's Pollution Prevention Policy. Demonstrate a strong preference for source
reduction by bold action, including resource shifts from end-of-pipe activities to
source reduction initiatives.
Allow flexibility to both States and industry to undertake efforts that will achieve
real reductions in pollution and generation of wastes.
Prioritize all efforts in pollution prevention based on the highest risks.
Establish expectations, accountability, and recognition of continuous improvement
in both the private and public sectors. Develop objective, measurable indicators of
success.
Empower the public. Involve the public more effectively in shaping EPA's
pollution prevention policies.
These messages are the building blocks for EPA's efforts to promote source reduction and
environmentally-sound recycling.
1.1.2 Draft RCRA Waste Minimization National Plan
The Draft RCRA Waste Minimization National Plan (RWMNP)4 is divided into two
phases. Phase I of the RWMNP is the primary vehicle for promoting source reduction and
recycling under EPA's Hazardous Waste Minimization and Combustion Draft Strategy; as part of
this phase, EPA identified hazardous wastes containing metals and halogenated organics as a
priority. Phase II of the RWMNP will then move beyond wastes managed in combustion units to
promote source reduction and recycling for wastes managed by other practices, applying the
messages heard and lessons learned during Phase I.
As shown in Exhibit 1-1, the process of setting priorities is one of the key building blocks
for the RWMNP. This process involves ranking hazardous wastestreams based on their hazard
and then ranking industrial processes (or sources) based on the wastestreams they generate.
4 U.S. EPA, May 23, 1994.
1-2
-------
EXHIBIT 1-1.
SUMMARY OF THE KEY COMPONENTS OF THE
DRAFT RCRA WASTE MINIMIZATION NATIONAL PLAN
ESTABLISH GOALS
Reduce quantity and toxicity of hazardous waste through source reduction and then recycling
' ' i
SET PRIORITIES FOR SOURCE REDUCTION AND RECYCLING
Rank wastestreams based on multi-media hazard and exposure potential, then
Rank industrial processes based on hazard of wastestreams they generate
Select priorities among industrial sectors, processes, wastestreams. and/or constituents
i
IDENTIFY/EVALUATE SOURCE REDUCTION AND RECYCLING OPPORTUNITIES
With the ultimate goal of optimizing source reduction above other methods, when feasible.
Consider:
Technical and economic feasibility
Economic impacts
Cross-media transfers
i
ARRAY MECHANISMS FOR EFFECTING SOURCE REDUCTION AND RECYCLING
Non-regulatory vs. regulatory mechanisms.
Consider:
Other EPA initiatives that are relevant
Which option(s) will result in the greatest environmental benefits
Resource constraints for effective outreach/implementation
Our sphere of influence
i .
IMPLEMENT MECHANISMS
Employ regulatory development, guidance, permitting, voluntary challenge programs, and
coordinate with Regions, States, technical assistance centers to both implement and develop
measures of success. _^_
i '
MEASURE PROGRESS BEING MADE
1-3
-------
The next step is to identify source reduction and recycling opportunities for priority
wastestreams and industrial processes and then evaluate their technical and economic feasibility,
economic impacts, and potential adverse environmental effects. This effort will involve a number
of parties, including EPA's Office of Research and Development and Office of Solid Waste,
industry, technical assistance centers, and universities.
Where source reduction and environmentally-sound recycling appear to be feasible
alternatives, the effectiveness of different voluntary and regulatory mechanisms for promoting
them will be examined. EPA will then encourage all stakeholders to identify the roles they can
play in further developing and implementing these mechanisms. The last step in the RWMNP is
measuring the progress being made.
The Agency is currently soliciting public comment on the Draft RWMNP. In addition,
EPA plans to conduct a focus group discussion during September 1994 to obtain public comment
on the different components of the RWMNP, including the prioritization methodology.5
1.2 PROCESS FOR REVIEWING DRAFT PRIORITIZATION METHODOLOGY AND
RESULTS
As discussed above, the messages heard from stakeholder groups at the November 1993
National Roundtable and the spring 1994 Regional Roundtables formed the foundation for
development of the RWMNP and the prioritization methodology. Informal guidance on
methodology development was provided by staff from a variety of Agency program offices during
review of potential methodologies and development of wastestream data. The Agency also
discussed comments on the RWMNP and prioritization methodology with representatives of some
stakeholder groups (e.g., States and industry trade associations). Finally, EPA briefed the Science
Advisory Board on the methodology and received some comments during a brief informal
consultation in June 1994.
The Agency plans to solicit and respond to comments on the prioritization methodology
and results in several ways prior to finalizing Phase I of the RWMNP. The Agency will review
and summarize the public comments provided both on the RWMNP and on this methodology
document. The Agency will also be establishing a formal Agency workgroup to develop the final
Phase I RWMNP, and one of the subcommittees on the workgroup will focus on reviewing and
revising the pnontization methodology based on both internal EPA and stakeholder group
comments. In addition, a focus group meeting is planned for September 1994 to formally obtain
comment from stakeholder groups on the Draft RWMNP; part of this meeting will serve as a
forum to obtain comment on details of the prioritization methodology.
The draft RWMNP discussed an earlier version of the prioritization methodology and presented
some initial pnontization results for the purpose of illustration. Attachment 1 to the RWMNP, which
showed a preliminary summary of high-ranking industry/source combinations, illustrated the level of detail
that could be provided in identifying industrial sources of hazardous waste generation. However
significant changes have been made to the underlying waste characterization data, and ranking results have
changed. See Chapter 3 for the revised ranking results
1-4
-------
13 ORGANIZATION OF DOCUMENT
Chapter 2 discusses the methodology used to identify the universe of combusted hazardous
wastes containing metals and/or halogenated organics and presents an overview of the results of
this process. Chapter 3 then discusses the selection of a hazard-based prioritization methodology
and the results of scoring wastestreams and industrial processes based on this methodology.
A series of appendices provide more detailed information on the prioritization
methodology and results:
Appendix 1 provides sample Biennial Reporting System (BRS) data forms.
Appendix 2 describes the codes used in the BRS.
Appendix 3 explains the process by which EPA linked information on waste
generation to information on off-site waste management.
Appendix 4 identifies sources of .information the Agency used to characterize
waste composition.
Appendix 5 explains EPA's assumptions in matching wastes reported in the 1991
BRS to wastes described and characterized in the 1987 Generator Survey.
Appendix 6 provides detailed waste characterization data for the highest-quantity
combusted wastestreams. .
Appendix 7 comprises a set of summaries, developed by EPA, of prioritization
systems. ,
Appendix 8 lists hazard data and pathway scores from the Superfund Chemical
Data Matrix, used in the Hazard Ranking System (HRS) and adapted for use in
this report.
Appendix 9 lists the states and regions in which the top 100 combusted
wastestreams occur.
1-5
-------
-------
CHAPTER 2
IDENTIFYING COMBUSTED HAZARDOUS WASTES
CONTAINING METALS AND HALOGENATED ORGANICS
This chapter summarizes EPA's methodology for identifying hazardous wastes containing
metals and/or halogenated organics managed in incinerators and in boilers and industrial furnaces
(BIFs). The first section of this chapter details the specific approach used to identify these
wastes; at the end of this section, several specific issues are listed on which EPA invites comment.
The second section presents a summary of results, and the last section presents limitations of the
methodology and the data.
2.1 METHODOLOGY
The methodology for identifying waste minimization priorities requires wastestream-
specific information on waste generation and management. The Biennial Reporting System
(BRS) data for 1991 represent the most comprehensive data available as of early 1994 to
characterize national waste generation and management1. Thus, the methodology relies heavily
on the BRS data. Section 2.1.1 describes the structure of the BRS, and some of the techniques
used to manipulate the data.
EPA analyzed the BRS data to determine the universe of combusted hazardous wastes,
that is, wastes managed in incinerators and BIFs. The overall purpose of this analysis is to
develop waste minimization priorities, which will serve as the basis for evaluating specific waste
minimization opportunities at the industry and process level. Thus, the analysis involved
identifying combusted wastes arid evaluating the origins of these wastes, as described in Section
2.1.2.
Within the universe of combusted wastes, the Agency decided to focus on those wastes
containing metals and/or halogenated organics. This decision was based on input from
participants in a series of national and regional Waste Minimization Roundtables, as well as
several factors related to human health and ecological risk. To characterize these combusted
wastes, it was necessary to identify the constituents present and to estimate their concentrations.
Section 2.1.3 describes this step, which is the final prerequisite to developing and applying a
hazard-based scoring system for setting waste minimization priorities.
2.1.1 Biennial Reporting System (BRS) Data Structure
The primary data used in the analysis were obtained from EPA's BRS database, which
contains information collected from the 1991 Hazardous Waste Reports. Every two years the
Agency collects data on hazardous waste from generators and treatment, storage, and disposal
facilities under the authority of Sections 3002 and 3004 of the Resource Conservation and
Recovery Act (RCRA), as amended by the Hazardous and Solid Waste Amendments (HSWA) of
1 The Agency is aware of the revisions made to the BRS data during June 1994, based on the Capacity
Assurance Plans (CAPs) submitted by the States, and plans to revise the analysis based on the updated
information.
2-1
-------
1984. The data are entered into an electronic data management system by the States. The
system is maintained by the Agency on the' EPA IBM mainframe cluster.
BRS data are stored in several relational database files. A relational database file system
is analogous to a simplified family tree. In this system there is one parent per child; parents can
have multiple children, and their children can have multiple children, and so on. In the relational
database system, there are parent records, child records, and grandchild records. For the purpose
of this document, the terms database, file, and table are synonymous, and are used
interchangeably for describing the BRS data.
The 1991 Hazardous Waste Report contains six forms:
(1) Form 1C (Identification and Certification) - All sites that are required to submit
the 1991 Hazardous Waste Report completed this form;
'(2) Form GM (Waste Generation and Management) - All facilities subject to the
reporting requirements that generated or shipped off site RCRA hazardous waste
during 1991 completed this form;
(3) Form WR (Waste Received From Off Site) - All sites that received RCRA
hazardous waste from off site during 1991 completed this form;
(4) Form PS (Waste Treatment, Disposal, or Recycling Process System) - All sites that
had an on-site hazardous waste treatment, disposal, or recycling process system
during 1991 completed this form, including sites with new units for which there
were firm plans, or closing units in the closure process;
(5) Form WM (Waste Minimization) - All large quantity generators and facilities with
treatment, disposal, or recycling units completed this form; and
(6) Form OI (Off-site Identification) - An optional form to be completed by the sites,
based on their State's requirements.
^n 2~l Shows that ^ IC Form * the "eldest" fonn 0"-e-> Parent to all other forms) in
A 5? Sy$tem> The IC Form contains one record for each facility uniquely identified by the
EPA ID number. All other forms (i.e., GM, WR, PS, and WM Forms) are children of the 1C
?^^ 6aCh IC Form (Le-' each facility) can have several of the children forms, each type
of child defines a new table in the 1C Form.
u- u 2"2 Presents some of the key da*a elements used in the analysis and identifies
which of the BRS Forms contained those data elements. Sample BRS Data Forms are presented
m Appendix 1. Please note that the Agency has not yet analyzed data from Form WM EPA
expects to compile and analyze data from this fonn in examining waste minimization
opportunities.
The BRS has been used to analyze waste minimization opportunities, treatment and
disposal capacity generation patterns, and recycling. As discussed later in the limitations section,
EPA recognizes that there have been some significant changes in waste generation and
2-2
-------
EXHIBIT 2-1. RELATIONSHIPS BETWEEN BRS FORMS
Form 1C
Identification and certification of
generators and treatment, storage,
and disposal facilities
36,000 records1
FormGM
Waste generation and management
220,000 records*
Form WR
Wastes received from off-site
facilities
700,000 records*
Section II
Wastes managed on-site
16,200 records*
Section 111
Wastes managed off-site
200,000 records*
1 Number of records is for all sites required to submit Hazardous Waste Reports in 1991.
2 Number of records is for all hazardous wastes generated and/or managed in 1991.
2-3
-------
EXHIBIT 2-2. KEY DATA ELEMENTS IN THE BRS
Data Element
Constituents reported to the Toxics Release Inventory (TRI).
Waste Origin refers to a description of the process or activity that was the source of the waste.
' Ne:ertheless« the 1»1 BRS data are the most recent data available and
a useful and comprehensive basis for characterizing and enumerating combusted
2.1.2 Identifying Combusted Wastes and Their Origins
T ^ B*!bil " °ne °f the data elements in the BRS is the management system
' °m nae thC We- EPA defined comb
t - - T° focus on those "n
wastes which afford the best initial opportunities for source reduction and recycling EPA
or
2-4
-------
Remediation wastes (source codes A61-A69); and
Spill cleanup, equipment decommissioning, and other remedial activity wastes (origin
code 2).
EPA also excluded residuals from on-site treatment, disposal, and recycling of hazardous waste
(i.e., secondary hazardous wastes) (origin code 5), in order to avoid double-counting between the
hazardous wastes that were treated/disposed/recycled and their residuals. Thus, EPA's
prioritization scheme is focussed on those primary hazardous wastes that are routinely generated.
For identifying wastes combusted on site, data from the on-site management section
(Section II) of the GM Form were used. For identifying wastes combusted o/f site, data reported
in the WR Form rather than data reported in the off site management section (Section III) of the
GM Form were used. The reason for using WR data rather than GM data is that WR data are
believed to provide a more reliable picture of how the waste was managed (for purposes of this
analysis, whether the waste was combusted or not). Even though generators may have better
knowledge of their wastestreams, they sometimes speculate on its management off site when
filling out the GM Form. For several reasons, the receiver would determine the exact properties
(and quantity) and appropriate management of the waste prior to treating it:
To determine the appropriate treatment system;
To determine the cost of treating the wastestreara; and
To avoid liability resulting from not having treated the waste to land disposal restriction
(LDR) standards.
Using the GM Form to identify wastes combusted on site, and the WR Form to identify wastes
combusted off site, the Agency determined the respective quantities to be 2.00 million tons and
1.04 million tons, for a total of about 3.04 million tons/year of routinely generated combusted
wastes.
Although the WR Form reliably identifies the management method for wastes sent off
site, it does not provide information on waste origins, as indicated by Exhibit 2-2. Because
information on the origins of the wastes is essential for identifying waste minimization
opportunities, the Agency developed a technique to merge data from the WR and GM forms (i.e.,
to identify waste source information from the GM Form for the wastes reported as combusted in
the WR Form).
This technique relied primarily on matching the GM and WR records based on their
common elements - generator and management facility identification numbers, RCRA waste
codes, management system type, and waste form codes. The process yielded relatively few exact
matches; only about 8 percent of the WR Form data (on a waste quantity basis) corresponded
perfectly to GM Form data. Initially, this left a large gap in the origins information for those
wastes managed off site. The Agency carefully investigated each of the top 50 records by waste
volume (as reported in the WR Forms) that remained unmatched; at this point, those records
comprised 50 percent of the total unmatched quantity. EPA was able to locate GM records that
corresponded to some of these WR records. This exercise provided insights that were used to set
up decision rules for a final computerized matching process, using relaxed matching criteria (e.g.,
allowing matches where waste quantities were within 25 percent of each other - see Appendix 3
2-5
-------
for a detailed description of the matching process). After completion of the process about 60
percent of the quantity of waste combusted off site (or about 20 percent of the total combusted
waste) could not be matched with corresponding GM data on waste origins.
c ... of the remaining "unmatched" quantity is associated with BRS records where the
facility identification numbers of other key data are missing. Another factor making it difficult to
match the GM and WR records is that the generating facilities tend to report quantities on an
annual basis whereas the receiving facilities often report quantities on the basfa of the amount in
individual shipments FmaUy, it is difficult to track origins for some of these wastes became they
have a complex path from "cradle" to "grave." Much of the waste that is ultimately burned off sL
is first routed from a generating facility to a fuel blending facility, where it may be proo2seS"n a
way that results in changes in the RCRA codes and regulatory status.3 For the purLTo7?h£
initial examination of combusted wastes, EPA did not attempt to match WR records back through
fue : blenders to generators, nor did it account for other situations where there are intermedSe
facilities that store or treat wastes prior to off-site combustion. Thus, while wastes routed through
intermediaries to incinerators or BIFs are included in EPA's estimate of total combusted waste
the origins of these wastes are currently unknown.
2.13 Identifying Constituents and Concentrations
Having identified the universe of wastes managed in combustion units and their origins
the next step in the methodology was to determine which of those wastes contain metals and/or
halogenated organics. As explained in more detail in Chapter 3 of this report, the Agency
decided to emphasize wastes bearing metals and halogenated organics in its initial priority-setting
for three principal reasons: r J ^«ms
A number of participants in a series of National and Regional Waste
Minimization Roundtables recommended focusing on these wastes.
Preliminary data suggest that metals arid halogens in combustor feed streams
contribute to emissions of metals and may contribute to the formation of
some toxic products of incomplete combustion (PICs), including dioxins and
furans.
Metals and halogenated organic constituents are generally toxic,
bioaccumulative, and persistent.
Therefore to determine whether combusted wastes contain metals and halogenated organics it
wa^ essential to identify which constituents are likely to be present in the wSes^ams' '
Moreover, the metoodology for ranking wastestreams is based not only on the presence of
11*' 355' MaSS * the Product of waste 1uan% and concentration;
lf31!? CXhibiting thC tOXicity characte"stic may be treated so that it no longer
<" T* renting b,ended
2-6
-------
Given the difficulty and effort involved in identifying constituents and estimating
concentrations, EPA decided to limit its initial waste characterization effort to the top 100 unique
groups of wastestreams, by volume, that contained metals and/or halogenated organics. The
combusted wastes were initially aggregated based on four key attributes: RCRA waste code set4,
standard industrial classification (SIC) code of the generator, source code of the process
generating the waste (e.g., spent process liquids removal, code A37), and form code for the waste
(e.g., concentrated solvent-water solution, code B201). All combusted wastestreams that were
identical in terms of the four attributes were grouped together. These aggregated wastes were
termed "wastestream combinations," and were ranked based on volume. EPA reviewed the
composition of the 150 largest-quantity wastestream combinations to identify the top 100
containing metals and/or halogenated organics. The top 100 wastestream combinations that
contain either metals or halogenated organics accounted for 1.52 million tons in 1991, or
approximately 50 percent of the total quantity of routinely generated, primary combusted
wastes.5
Information Sources
The primary sources of information for identifying constituents were the Chemical
Abstract Service (CAS) numbers, RCRA codes, and waste descriptions given in the BRS. The
Agency also used several other supplementary sources to identify constituents and estimate
concentrations. Not all information sources were available for each wastestream, so EPA had to
apply professional judgement on when to use the sources, and when to make assumptions to
bridge data gaps. The major information sources are described below, in approximate order of
preference.
CAS numbers of Toxic Release Inventory (TRI) constituents. When a waste contains
constituents for which the generator has submitted a TRI report, the generator must
identify those TRI constituents in its biennial report. Most of the metals and
halogenated organics of concern to EPA are included in the list of TRI constituents.
The BRS contains this information where it was reported by the generator, but it does
not provide information on constituent concentrations.
RCRA codes. As described above, RCRA codes provide some information on the
constituents present in wastestreams. The toxicity characteristic (TC) RCRA codes,
D004 through D043, identify constituents present and also indicate that concentrations
exceed the set of corresponding regulatory levels (expressed as concentrations measured
by a leaching procedure). The P- and U-wastes (off-specification products, spill
residues, and related wastes) also identify specific constituents that are present, and
4In the BRS, all relevant RCRA waste codes (e.g., D001 [characteristic of ignitabilityj, F001 [spent
halogenated solvents from degreasing]) that apply to a waste are reported. In some cases, 20 or more
individual codes can be reported in a "code set," although it is more typical to have five or fewer codes.
EPA truncated code sets at ten individual codes.
5Note that the Agency defines "wastes that contain metals and/or halogenated organics" to be wastes
where one or more of constituents in these groups was identified as being present, regardless of the
concentration. Some information sources provided information on trace constituents of wastes. For this
reason, some wastes with extremely low concentrations are defined as containing metals or halogenated
organics. However, hazard rankings for these wastes will reflect the low concentrations, since hazard score
is directly proportional to concentration.
2-7
-------
generally connote wastes with relatively high concentrations (unless mixed with other
wastes). The K-waste (industry-specific process waste) and F-waste (generic process
waste) codes can provide an indication of which constituents are present - EPA's
original waste listing decisions and its determinations of best demonstrated available
technology (BOAT) for the wastes' treatment cite the constituents which are of primary
concern from a risk or treatability standpoint A list of documents providing
concentration data for some of the RCRA wastes evaluated for this project appears in
Appendix 4. J vv
Waste descriptions. For the biennial reports, generators are asked to provide
descriptions for each waste they report. In some cases, these descriptions provide
insight on waste constituents, although they rarely provide concentrations.
Waste form codes. The BRS also contains a series of waste form codes that provide an
indication of the physical form of the waste. These codes fall into several broad
categories, including inorganic liquids, organic liquids, inorganic solids, organic solids
inorganic sludges, and organic sludges. As explained later, EPA made several
assumptions on concentrations of constituents in various waste forms.
' Retrievals from the Generator Survey fGENSTTE) in 1937, EPA performed an
extensive survey of hazardous wastes managed as of 1986. One of the questions posed
in this survey asked for information on constituents and concentrations. Although EPA
recognizes that there may have been major changes in waste generation and
management patterns since 1986, the GENSUR data still provide some useful
information on waste composition, especially where there was a good match between
the waste attributes reported in the BRS and those in the GENSUR.
Like the Biennial Report, the GENSUR collected information on RCRA code set,
waste form, the activity or process generating the waste, and the SIC of the generator
u/2Sc^deS 3nd S°Urce Codes in the BRS do not correspond directly with those in
the GENSUR, so EPA developed a cross-reference between the two data sets. The
Agency also developed decision logic to match wastestreams from the BRS with those
from the GENSUR, and retrieved data from the GENSUR to help inform the
estimates of waste composition. A description of the protocol EPA used to retrieve
information from the GENSUR is provided in Appendix 5.
In addition to the GENSUR retrievals made specifically for this project, EPA used
several earlier analyses of GENSUR data on D001 through D003 wastes.6 These
codes occur very frequently among the combusted wastestreams.
«.,n0t S0rt concentratio«s °f the ignitable (D001), corrosive (D002), and
reactive (D003) wastes by SIC, form code, or activity code, and thus provide a coarser degree of resolution
' "T" ^ENSUR retrieValS- Nevertheless' w»>ere no match could be made on SIC, form or
used results from these analyses, which appear in two memoranda from ICF Incorporated to
2-8
-------
Approach
Using, these information sources, EPA made its estimates of waste composition by applying
the following methods and assumptions. The initial step involved determining which hazardous
constituents are most likely to be present. Although the Agency is initially focusing its priority-
setting efforts on metals and halogenated organics, for each of the top 100 combusted wastes that
contain one or more of these constituents, EPA sought to identify all other important hazardous
constituents as well.
Identifying constituents. The sequence for identifying hazardous constituents follows.
1) The TRI constituents and waste descriptions reported in the BRS were the
preferred basis for identifying hazardous constituents. If the reported constituents
could plausibly account for all of the RCRA codes reported, EPA assumed that no
additional hazardous constituents were present.
2) Otherwise, the next step was to evaluate all RCRA codes in the code set, to
determine which constituents were likely to be present. For the D004-D043 TC
wastes, and the P- and U-wastes this was straightforward. For the listed process
wastes (F- and K-wastes), this involved reviewing the documents listed in Appendix
4.
3) GENSUR data were used to identify some of the less obvious constituents,
particularly if it was possible to match the BRS and GENSUR data closely, and if
constituent and concentration data were available for the GENSUR match.
4) If D001, D002, and/or D003 were reported in the code set, but were not
accounted for based on the constituents identified as likely to be present, EPA
assumed that
- for D001, toluene, xylene, cadmium, lead, and chromium were present; these
constituents were reported to be present most frequently (i.e., in more than 35
percent of all D001 wastes) across the GENSUR;
- for D002, corrosivity was due to hydrochloric acid;
for D003, reactivity was due to sulfides (unless the form code indicated presence
of reactive cyanides).
Estimating concentrations. The next step involved estimating concentrations. The
primary indicators of concentration were the waste description, form code, and source code. In
general, the Agency assumed that organic liquids had the highest concentrations of constituents
(usually on the order of 90% organics) and aqueous liquids had the lowest concentrations (total
concentration of individual constituents usually on the order of 10,000 ppm or lower). Many of
the listing and BDAT documents listed in Appendix 4 provide information on compositional
analyses of wastes; EPA often used these sources to estimate concentrations. EPA also used the
GENSUR data, especially when there was a good match, i.e., the RCRA codes and form codes
matched well.
2-9
-------
attributes:
EPA applied some assumptions to account for several of the most commonly occurring
H the RCRA code set included D002 (corrosivity characteristic), and none of the sped
fie constituents likely to be present accounted for corrosivity, it was generally assumeT
that corrosivity was due to hydrochloric acid at a concentration of abolt 500 ppm
Similarly if the RCRA code set included D003 (reactivity characteristic) and this was
not attributable to any of the specific constituents that had been identiffe the Agency
er "" ^ feaCtiVit Sulfide at a
If the RCRA code set included toxicity characteristic constituents, and if there was no
indication that their concentrations were relatively high, EPA assumed hat the
concentrations were 200 times their respective regulatory levels.7
key atteft °f *" characterization eff°*- s attachment lists the
^
characterization. An example of the information provided in Appendix 6 appears in Exhibit 2-3.
Issue #1:
Issue #2:
Issue #3:
=^ ^^^^^^^^^^^^^^^
The Agency recognizes that the characterization of wastestream
constituents and concentrations in this document is based on highly
uncertain data, and embodies significant professional judgement EPA
invites comment from reviewers on the specific waste characterization
assumptions shown in Appendix 6. Are there other readily-available
sources of waste characterization data (e.g., collected by state
regulatory agencies or technical assistance centers) that could be
employed for hazard ranking?
How might future waste characterization data be collected most
efficiently, both for the purpose of setting waste minimization priorities
and for measuring progress? Are there innovative approaches (e.g.,
partnerships with treatment, storage, and disposal facilities) that could
oe employed?
It is difficult to track wastes that are processed by fuel blenders and
subsequently combusted. Are data available on the composition of
these wastes and of the blended fuels that are derived from them?
ppm werJ!£££ ^^^ Wgh benzene """^tions, °" the order of 100,000
2-10
-------
EXHIBIT 2-3. CONSTITUENT AND CONCENTRATION INFORMATION FOR EXAMPLE WASTESTREAM COMBINATIONS
RANK
1
2
RCRAwaik«4«
V
v1
D001D002U006
U113
D002 D021 D028
F003FOOS
SICCrft
J
J
2869
2879
S»m»
C»tt
A3}
A37
tarn
(Mt
»
B101
B10I
Qiull*
189.524
130,948
*
ws
1
1
*
r.c
i
i
C«utUl»U CMC. (»»)
Acrylic acid 750
Ethyl acryiau; 50,000
Acrolein 750
n-BuUnol 50
Chromium 1
Formaldehyde 750
Malefc anhydride 50
Ptalhalic anhydride 50
Methyteiw chloride 20,000
Elbylenc dichloride 10,000
Methyl Uobutyl ketone 10,000
Toluene 2.000
Chlorobenzene 50,000
Hydrochloric add 500
CmtilMl S»in«
RCRA codes
RCRA codes
Gen. Survey
Gen. Survey
Gen. Survey
Gen. Survey
Gen. Survey
Gen. Survey
BRS CAS number!
BRS CAS number,
BRS CAS numbers
BRS CAS numbers
RCRA wiste code
None
K
-------
Z2 DRAFT RESULTS
This section summarizes the characteristics of combusted wastes containing metals and/or
halogenated organics. Section 2.2.1 provides perspective at a very broad scale, placing combusted
wastes within the overall hazardous waste universe, and briefly describing some of the
characteristics of the combusted waste universe (i.e., routinely generated primary waste and non-
routinely generated secondary waste). Characteristics and origins of routinely generated primary
combusted wastes are discussed in Section 2.2.2. Finally, in Section 2.2.3 the Agency describes
the set of wastes that are evaluated in Chapter 3 - the top 100 combusted wastestream
combinations that contain metals and/or halogenated organics.
2.2.1 Overview of Combusted Wastes
About 306 million tons of hazardous waste are managed in units subject to the permitting,
design, operating and maintenance, and closure requirements of Subtitle C. As shown in Exhibit'
2-4, the total quantity managed in on-site and off-site incinerators and BIFs was about 3.57
million tons/year. About 0.53 million tons (or 15 percent of the total combusted wastes) are the
wastes generated from the remediation and other processes as "secondary" or "one-time" wastes.
Thus, after excluding secondary and one-time wastes, about 3.04 million tons of routinely
generated, primary wastes are combusted at on-site and off-site facilities.
EXHIBIT 2-4
QUANTITY OF COMBUSTED HAZARDOUS WASTE
BY PLACE OF MANAGEMENT AND GENERATION PATTERN
Place of Management
On site
Off site
Total Wastes Combusted
at RCRA-permitted units
Quantity (million tons)
Routinely Generated
Primary Waste
2.00
1.04
3.04
One-time and
Secondary Waste
0.38
0.15
0.53
Total
2.38
1.19
3.57
2.2.2 Characteristics and Origins of Routinely Generated, Primary Combusted Wastes
This project focusses on setting waste minimization priorities for the set of routinely
generated, primary combusted wastes, hereinafter referred to as "combusted wastes". Some of the
principal characteristics of these wastes, and their origins, are summarized below.
Place of Management and Type of System
Exhibit 2-4 above shows that about two-thirds of combusted wastes were managed on site
in 1991. Slightly more wastes were incinerated than burned in energy recovery systems - the
proportions are 55 percent and 45 percent, respectively. In both categories, liquids (which may
2-12
-------
include pumpable sludges) dominated the quantities managed. Liquid incineration accounted for
44.2 percent of combustion; energy recovery from liquids accounted for 40.2 percent; and thus
close to 85 percent of the wastes were managed by liquid-injection based combustion systems.
Sludges and solids accounted for virtually all of the remaining 15 percent
In the two largest categories of combustors, liquid incineration and liquid energy recovery
systems, information on the physical form of the wastes burned indicates that there is probably a
distinction in the energy content of the wastes.
Within the largest category of combustors, liquid incineration, aqueous waste with low
solvents (B101) was the dominant waste form, comprising almost 40 percent of the
liquid incineration volume. Virtually all (99 percent) of the aqueous waste solvents that
are combusted are burned in liquid incineration units.
In the other major combustor category, liquid energy recovery systems (i.e., BIFs
burning liquids), the most common form of waste was unspecified organic liquids, which
constituted almost one-third of the volume managed by these units. The other waste
forms occurring most frequently in the liquid-burning BIFS are waste oils (12 percent)
and halogenated/non-halogenated solvent mixtures (10 percent).
Waste source
The BRS contains information on the types of processes which generate each
wastestream. Major categories of sources of combusted wastes in 1991 included cleaning and
degreasing, surface preparation and finishing, processes other than surface preparation, and
several other categories. As shown in Exhibit 2-5, three specific source categories comprised
more than 50 percent of combusted wastes:
Product distillation (A33) - 22.6 percent
Spent process liquid removal (A37) - 16.9 percent
By-product processing (A35) -10.9 percent
There is a marked decrease in the quantities generated by other processes the fourth largest
process accounted for only about 2.8 percent, and an additional 19.7 percent was made up by 54
different processes. For the remaining 28 percent, the source code was not entered or could not
be identified.
Waste Form
Fifty percent of the wastes combusted in 1991 were classified as organics liquids. One-
fourth of the wastes were inorganic liquids. Sludges and solids accounted for most of the
remaining wastes where waste form is known (12.5 percent).
Two specific waste forms dominated the combusted wastes "other organic liquids" (B219)
with 18.3 percent and "aqueous waste with low solvents" (B101) with 17.8 percent. These two
waste forms accounted for 36 percent of the total combusted wastes. Exhibit 2-6 lists the
proportions of combusted wastes represented by other specific form codes.
2-13
-------
EXHIBIT 2-5
SOURCES GENERATING COMBUSTED WASTES
Volume
(tons)
Cum. %
of
Volume
Source Code Description
Product distillation
Spent process liquids removal
By-product processing
Product filtering
Product solvent extraction
Discarded of: oec material
8 Other pollution control or waste treatment
Wastewater treatment
Clean out process equipment
Product rinsing
Other non-surface preparation processes
Incineration/Thermal treatment
Other production-derived l-time and intermit
processes
Solvents recovery
Other cleaning and degreasing
Filtering/screening
20 Air pollution control devices
All other source codes
2-14
-------
EXHIBIT 2-6
PHYSICAL FORM OF COMBUSTED WASTES
Volume
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Form Code Description
Other organic liquids
Aqueous waste with low solvents
Unknown
Halogenated/non-halogenated solvent mixture
Concentrated aqueous solution of other organics
Waste oil
Non-halogenated solvent
Halogenated solvent
Aqueous waste with low other toxic organics
Still bottoms of non-halogenated solvents
Concentrated solvent-water solution
Caustic aqueous waste
Resins
Reactive or polymerizable organic liquid
Other halogenated organic solids
Other non-halogenated organic solids
Acidic aqueous waste
Halogenated pesticide solid
Solid resins or polymerized organics
Lime sludge with metals/metal hydroxide sludge
Oil-water emulsion or mixture
Oilv sludge
Concentrated phenolics
Still bottoms of halogenated solvents
Other waste inorganic solids
Paint thinner or petroleum distillates
Mixed lab packs
Aqueous waste with reactive sulfides
Soil contaminated with organics
Organic paint or ink sludge
All other form codes
Total
Form
Code
B219
..B101
Unk.
B204
B207
B206
B203
B202
B102
B602
B201
B110
B606
B212
B407
B409
BIOS
B401
B403
B503
B20S
B603
B208
B601
B319
B211
BOOS
Bill
B301
B604
Volume
(tons)
555,704
541.130
378,429
216,867
181,638
152,777
152.582
110,706
92,907
86.802
71,891
65.893
38,123
34,650
34,522
33,728
30,625
27,031
23,150
22.221
20,386
18,885
18,639
16,273
14,374
11,752
7,651
7,511
7,385
7,205
56,430
3,037,866
%of
Volume
18.29
17.81
1X46
7.14
5.98
5.03
5.02
3.64
3.06
2.86
2.37
2.17
1.25
1.14
1.14
1.11
. 1.01
0.89
0.76
0.73
0.67
0.62
0.61
0.54
0.47
0.39
0.25
0.25
0.24
0.24
1.86
100.00
Cum. % of
Volume
18.29
36.11
48.56
55.70
61.68
66.71
71.73
75.38
78.43
81.29
83.66
85.83
87.08
88.22
89.36
90.47
91.48
92.37
93.13
93.86
94.53
95.15
95.77
96.30
96.78
97.16
97.41
97.66
97.91
98.14
100.00
2-15
-------
Industrial Sectors
Overall, close to 400 industries (as defined by four-digit SIC codes) generated waste
destined for combustion in 1991. However, as with most of the other attributes of combusted
waste, much of the quantity was concentrated in a few sectors. The dominant individual sector
was industrial organic chemicals (SIC Code 2869), which generated about 40 percent of the
combusted waste in 1991 (see Exhibit 2-7). The next two sectors for which information was
available - pesticides and agricultural chemicals (2879) and plastic materials and resins (2821) -
accounted for 15 percent of the quantity, and the remaining codes accounted for less than 23
percent in aggregate.
m At the broad industrial category (two-digit SIC) level, the chemical and allied product
industry generated (SIC code 28) almost two-thirds of total .combusted wastes The next two
industries generating the most wastes were petroleum and coal (2.6 percent) and electric, gas and-
sanitary service (1.3 percent). The SIC was unknown for about 25 percent of the volume
RCRA Waste Codes
Each wastestream is defined by all applicable RCRA waste codes. Among the combusted
wastes, there were about 9,500 different combinations of RCRA codes (i.e., "RCRA code sets") in
1991. More than 450 unique RCRA waste codes occurred within these 9,500 code sets. About 8
percent of the total combustion wastes did not have a RCRA waste code.
The top five code sets accounted for about 28 percent of the total combusted quantity
The most commonly occurring individual codes were D001 (ignitable) and D002 (corrosive).
Location
Facilities located in EPA Region 6 generated and managed close to 50 percent of the
combusted wastes in 1991. Regions 7, 5, and 2, which managed close to 10 percent each, were
the other top three regions managing waste.
Within Region 6, Texas generated and managed approximately 40 percent of the total
waste combusted in the nation, or close to 80 percent of the wastes generated and managed in
Region 6. No other state generated or managed more than 10 percent of the total combusted
T^ J^SOUri-(MO)' L0* (LA), to** (IN), and New Jersey (NJ) each managed more
than 100,000 tons of waste, and took second to fifth places in that order for both waste
generation and management
Size Distribution of Combustion Facilities
A total of 430 facilities combusted wastes in 1991.8 The top five facilities, each managing
more than 100,000 tons, burned close to 25 percent of the combusted wastes. The top 25
facilities managed 60 percent of the wastes. Three out of the top five facilities manarine the
waste were located in Texas.
p
As of 1994, the universe of combustion facilities was smaller.
2-16
-------
EXHIBIT 2-7
INDUSTRIAL SECTORS GENERATING COMBUSTED WASTES
Volume
Rank
I
2
3
4
'5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
SIC Code Description
Industrial Organic Chemicals, N.E.C.
Unknown
Pesticides and Agricultural Chemicals, N.E.C.
Plastics Materials, Synthetic Resins, and
Nonvulcanizable Elastomers
Pharmaceutical Preparations
Medicinal Chemicals and Botanical Products
Cyclic Organic Crudes and Intermediates, and
Organic Dyes and Pigments
Petroleum Refining
Industrial Inorganic Chemicals, N.E.C.
Refuse Systems
Business Services, N.E.C.
Photographic Equipment and Supplies
Chemicals and Chemical Preparations, N.E.C.
Nonclassifiable. Establishments
Synthetic Rubber (Vulcanizable Elastomers)
Glass Containers
Electric Services
Paints, Varnishes, Lacquers, Enamels, and
Allied Products
Chemicals and Allied Products, N.E.C.
Services, N.E.C.
Manmade Organic Fibers, Except Cellulosic
Manufacturing Industries, N.E.C.
Wood Household Furniture, Upholstered
Ammunition, Except for Small Arms
National Security
All other SIC codes
Total
SIC
Code
2869
Unk.
2879
2821
2834
2833
2865
2911
2819
4953
7389
3861
2899
9999
2822
3221
4911
2851
5169
8999
2824
3999
2512
3483
9711
Volume
(tons)
1,147,907
752,693
287,214
172,634
114,390
98,137
85,652
78,700
53,271
31,083
24,705
21,642
20,065
17,370
12,289
9,038
7,579
5,788
5,559
4,706
4,584
4,454
4,341
3,658
3,603
66,825
3,037,866
%of
Volume
37.79
24.78
9.45
5.68
3.77
3.23
2.82
2J59
1.75
1.02
0.81
0.71 ,
0.66
0.57
0.40
0.30
0.25
0.19
0.18
0.15
0.15
0.15
0.14
0.12
0.12
2.20
100.00
Cum. % of
Volume
37.79
62.56
72.02
77.70
81.47
84.70
87.52
90.11
91.86
92.88
93.70
94.41
95.07
95.64
96.05
96.34
96.59
96.78
96.97
97.12
97.27
97.42
97.56
97.68
97.80
100.00
2-17
-------
2.23 Characteristics of the Top 100 Combusted Wastestreams Containing Metals and/or
Halogenated Organics
Employing the techniques described in Section 2.1.3. EPA determined which constituents
were present m large-volume wastestream combinations, and identified the top 100 (bv quantity!
that contain metals and/or halogenated organics: It is this set of 100 wastestream combinations
that is earned through to the priority-setting procedure described in Chapter 3.
EPA's waste characterization effort indicates that a wide variety of constituents are
present m these top 100 wastestream combinations. As discussed earlier, the primary focus was
on identifying specific metals and halogenated organics likely to be present but EPA also
attempted to identify other toxic constituents as well. Exhibit2-8 lists the metals, halogenated
organics, and other constituents identified in the top 100 wastestream combinations.
f , identified the characteristics of the top 100 combusted wastestream combinations
(ranked by amount of waste generated) that contain metals or halogenated organics To
determine the extent to which these wastestream combinations represent the universe of
combusted wastes, the Agency also compared the top 100 combinations with all other combusted
wastestream combinations in the BRS database (a set of 18,922). For both tasks (identifying the
characteristics of the top 100 wastestream combinations, and making the comparison with other
wastestreams) EPA considered (1) quantity of waste generated (in tons), (2) the form of the
waste as indicated by the form code, (3) whether the wastes are managed on site or off site (4)
the industry group generating the waste, as indicated by the SIC code, (5) the source of the waste,
as shown by the source code, and (6) the RCRA waste codes represented.
-^ -a deveI°Ped a computer program in SAS (a statistical analysis software package) to
identify the characteristics of the top 100 wastestream combinations and to compare this group
with the remaining combusted wastestreams. The SAS outputs provide the frequency of each
form code, SIC code, etc. in (I) the top 100 wastestreams, and (2) the remaining wastestreams
The frequencies were calculated in two ways, unweighted and weighted. The unweighted
frequencies do not account for the amount of waste represented by each wastestream The *
weighted frequencies give more weight to instances where a given form code, SIC code, etc is
associated with a large-volume wastestream.
The analysis of the frequencies of RCRA waste codes is slightly more complex because
many wastestreams contain more than one RCRA waste code. The frequency of a given RCRA
waste code m the top 100 wastestream combinations is defined as (1) the number of wastestreams
rnlS1- n6 ?T wast^de occurs> divided by (2) the total number of occurrences of all waste
codes in all of the top 100 wastestream combinations. The frequency of each waste code in the
remaining wastestreams was calculated in the same manner.
EPA'S
are described below' for each of the characteristics
Amount of Waste Generated
wa^;esutream combinations that contain metals or halogenated organics
BRSd °f *U the quantity of routinely generated primary combusted wastes in the
BRS database. Specifically, the top 100 wastestreanrcombinations accounted for 1.52 million tons
2-18
-------
EXHIBIT 2-8
LIST OF CONSTITUENTS IN THE TOP 100 WASTESTREAM COMBINATIONS
Metals
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Vanadium
Zinc
Halogenated Organics
1-chloro, 2,3-epoxy propane
1.1 -Dichloroethane
1,1-Dichloroethylene
1,1,1-Trichloroethane
1,1,1,2-Tetrachloroethane
1,1,2-Trichloroethane
1,1,2,2-Tetrachloroethane
1,2-Dichloro benzene
1,2-Oichloroethane
1,2-Dichloropropane
1,2,3-Trichloropropane
1,3-Dichloropropylene
l,4-Dichloro-2-butene
1,4-Dichlorobenzene
2-Chloro-l,3-butadiene
2,3,7,8-Tetrachlorodibenzo
(p)dioxin
2,4-Dichlorophenoxy acetic
acid ,
2,4-Dichlorophenoxyacetic
acid
2.4,5-Trichlorophenol
3-Chloropropene4,4-methyl
ene bis(2-chloroaniline)
Acetyl chloride
Allyl chloride
Benzal chloride
Benzo trichloride
Bis (2-chloroethyt) ether
Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloroprene
Chloropyridine
Cis 1,3-dichloropropene
Dichloro benzene
Dichlorodifluoromethane
Dichloropropene
Epichlorohydrin
Ethylidine
dichlorideHexachloro benzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Methyl chloride
Methylene chloride
o-Dichlorobenzene
p-Dichlorobenzene
PCBs
Tetrachlorobenzene
Tetrachloroethylene
Trans 1,2-dichloroethene
Trans 1,3-dichloropropene
Trichloroethylene
Trichlorofluoromethane
Trichlorotrifluoroethane
Vinyl chloride
Other Constituents
a-Methyl styrene
1,2,4-Trimethylbenzene
1,4-Diethylene oxide
2,4-Dimethyl phenol
2,4-Toluene diamine
2,6-Toluene diamine
2,6-Dimethyl phenol
Acenaphthalene
Acenaphthene
Acetaldehyde
Acetic acid
Acetone
Acetonitrile
Acetophenone
Acrolein
Acrylamide
Acrylic acid
Acrylonitrile
Ammonia
Aniline
Anthracene
Benz(c)acridine
Benzene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(j)flaoranthene
Bis (2-ethylhexyl) phthalate
Butanol
Butyl acrylate
Butyl benzal phthalate
Butyl benzyl phthalate
Carbon disulfide
Chrysene
Cresols
Cumene
Cumyi phenol
Cyanide
Cyclohexane
Cyclohexanone
Dibenz(a,h)anthracene
Diethyl sulfate
Oiethylhexyl phthalate
Dimethyl phthalate
Diphenyl amine
Diphenylamine
Ethanol
Ethyl acetate
Ethyl acrylate
Ethyl ether
Ethylbenzene
Ethylene glycol
Ethylene grycol monoethyl
ether
Ethylene oxide
Ethyleneimine
Fluoranthene
Fluorene
Fluorine
Formaldehyde
Hydrazine
Hydrochloric acid
Hydrocyanic acid
Hydrogen sulfide
Isobutanol
Isobutyraldehyde
Isoheptane
Isopropanol
Ketocarbamate
Limonene
Maleic anhydride
Methanol
Methyl acetate
Methyl ethyl ketone
Methyl isobutyl ketone
Methyl methacrylate .
Morpholine
n-Butanol
Naphthalene
Nitrobenzene
Octamethylpyrophosphoramide
Pentane
Phenanthrene
Phenol
Phorate
Phosphoroamidothioate
Phosphorodithioic acid esters
Phosphorothioic acid esters
Phthalic anhydride
Propanol
Pyrene
Pyridine
Styrene
Sulfuric acid
Toluene
Toluene-2,4-diisocyanate
Toluene-2,6-diisocyanate
Toluene diisocyanate
Vinyl acetate
Xylene
2-19
-------
of waste, whereas the total amount of waste in all of the combusted wastestreams combined was
3.04 million tons.
Predominant Waste Forms
The BRS waste forms can be evaluated in terms of broad categories (e.g., organic liquids;
inorganic liquids), or at a very specific level (e.g., concentrated solvent-water solution; metal scale,
filings, or scrap). The predominant waste forms among the broad categories, both for the top 100
wastestream combinations and for the remaining set, were organic liquids and inorganic liquids
(see Exhibit 2-9).
EXHIBIT 2-9
WASTE QUANTITY BY CATEGORY OF WASTE FORM
(Percent of Total Waste Quantity)
Waste Form
Organic liquids (B201-B219)
Inorganic liquids (B101-
B119)
Organic sludges (B601-B609)
Unknown or invalid data
Organic solids (B401-B409)
Inorganic sludges (B501-
B519)
Inorganic solids (B301-B319)
Lab packs (B001-B009)
Organic gases (B801)
Inorganic gases (B701)
Total:
Top 100
Wastestream
Combinations
46.8
35.2
8.4
5.3
3.0
1.3
0.0
0.0
0.0
0.0
100
All Other
Wastestreams
54.1
14.3
2.8
19.7
5.7
0.5
2.1
0.7
<0.1
<0.1
100
At the level of the specific waste form, the predominant forms hi the top 100 wastestreara
combinations were substantially different from those in the remaining wastestreams. The most
common in the top 100 wastestream combinations, aqueous waste with low solvents (B101),
accounted for 32 percent of the quantity of these wastestreams, but only 3 percent of the
remaining wastestreams. The next most common waste form in the top 100 wastestream
combinations, other organic liquids (B219), accounted for 23 percent of the quantity of these
wastestreams, but a substantially lower proportion (13 percent) of the remaining wastestreams.
2-20
-------
The third most common waste form in the top 100 wastestream combinations, halogenated/
nonhalogenated solvent mixtures (B204), accounted for 9 percent of these wastestreams, but only
5 percent of the remaining wastestreams.
Two waste forms were common in the remaining wastestreams that were not common in
the top 100 wastestream combinations. Concentrated aqueous solutions of other organics (B207)
accounted for 10 percent of the remaining wastestreams, as opposed to only 2 percent of the top
100 wastestream combinations. Non-halogenated solvents (B203) accounted for 9 percent of the
remaining wastestreams but only 1 percent of the top 100 wastestream combinations.
The waste form was unknown for 5 percent of the top 100 wastestream combinations and
for 20 percent of the remaining wastestreams.
On-Site vs. Off-Site Management
On-site waste management was more common for the top 100 wastestream combinations
than for the remaining wastestreams, as shown in Exhibit 2-10. This is because generators of
large quantities of waste can often take advantage of economies of scale and invest in the
necessary equipment to manage their own wastes. For generators of smaller quantities of wastes,
it is often more cost-effective to ship wastes off site for management.
Exhibit 2-10
On-Site Vs. Off-Site Management
Location of
Waste Management
On site
Off site
Top 100
Wastestream combinations
75 percent
25 percent
Remaining
Wastestreams
57 percent
43 percent
A more detailed presentation of the waste management options selected by the generators
of the top 100 wastestream combinations is presented in Exhibit 2-11. As this exhibit shows, two-
thirds of wastes managed on site were incinerated, with the remainder combusted in BIFs. Of the
wastes managed off site, over 90% were combusted in BIFs.
Inorganic liquids managed on site were far more common in the top 100 wastestream
combinations (accounting for 35 percent of waste quantity) than in the remaining wastestreams
(where they account for only 13 percent of the wastes). Only a small amount of inorganic liquids
in either set of wastestreams was managed off site. Wastes other than inorganic liquids comprised
60 percent of the top 100 wastestream combinations and 66 percent of the remaining
wastestreams. In both sets, about two-thirds of the wastes other than inorganic liquids were
managed on site.
2-21
-------
EXHIBIT 2-11
SUMMARY OF QUANTITY OF TOP 100 COMBUSTED WASTESTREAM COMBINATIONS
BY PLACE, TYPE, AND COMMERCIAL STATUS OF MANAGEMENT FACILITIES
Place of
Management
On site
Off site
Commercial
Status
Commercial
Non-
commercial
Type of
Management
Incineration
Incineration
BIF
Total:
Tptal:
Commercial
Non-
commercial
Incineration
BIF
Total:
Incineration
BIF
Total:
Total:
Waste Quantity
(millions of tons)
4,565
756,958
382,565
1,139,523
1,144,088
24,492
232,351
256,843
6,239
117,374
123,613
380,456
Percent of
Total Wastes
0.3
49.6
25.1
74.7
75.0
1.6
15.2
16.8
0.4
7.7
8.1
24.9
Industrial Sectors Generating the Most Waste
Two industry groups accounted for 52 percent of waste quantity from the top 100
wastestream combinations, and 42 percent of the waste from the remaining wastestreams. Fully
37 percent of the waste in the top 100 wastestream combinations is generated by the industrial
organic chemical industry (SIC code 2869).. This industry generates, a nearly identical proportion
(38 percent) of the remaining wastestreams. Fifteen percent of the waste in the top 100
wastestream combinations is generated by the agricultural chemicals industry (SIC code 2879).
This industry, however, is only responsible for four percent of the waste generated in the
remaining wastestreams. No other SIC code accounts for more than 7 percent of either the top
100 or the remaining wastestreams. The SIC code was unknown for 20 percent of the top 100
wastestream combinations and for 30 percent of the remaining wastestreams.
Predominant Sources of Wastes
The predominant source codes, and their rankings, were the same for both the top 100
wastestream combinations and the remaining wastestreams. The most common source was
product distillation (source code A33), accounting for 29 percent of the top 100 wastestream
combinations and 16 percent of the remaining wastestreams. The next most common source was
spent process liquids removal (source code A37), accounting for 22 percent of the top 100
2-22
-------
wastestream combinations and 12 percent of the remaining wastestreams. The third most
common source was by-product processing (source code A35), accounting for 14 percent of the
top 100 wastestream combinations and 8 percent of the remaining wastestreams. No other waste
source accounted for more than 5 percent of either set of wastestreams. The waste source was
unknown for 23 percent of the top 100 wastestream combinations and for 33 percent of the
remaining wastestreams.
RCRA Waste Codes
The most common RCRA waste codes were the same in both the top 100 wastestream
combinations and the remaining wastestreams, with one exception. The most common waste
codes, and their respective percentages for the top 100 wastestream combinations and the
remaining wastestreams, are as follows:
D001, ignitable waste (20 percent and 27 percent),
D002, corrosive waste (13 percent and 10 percent),
F002, certain spent halogenated solvents and still bottoms (7 percent and 3 percent),
F003, certain spent non-halogenated solvents and still bottoms (6 percent and 8
percent), and
F005, certain spent non-halogenated solvents and still bottoms (6 percent and 4
percent).
The one RCRA waste code that was significantly more common in the remaining wastestreams is
D018, toxicity characteristic for benzene, which accounted for only 2 percent of the top 100
wastestream combinations but represented 8 percent of the remaining wastestreams.9
Locations
Exhibit 2-12 shows the quantities of wastes in the top 100 wastestream combinations
generated in each state. As the exhibit shows, two states (Texas and Missouri) account for more
than half of these wastes (43 percent and 14 percent respectively).
Wastes Requiring Further Study
EPA has experience in developing waste minimization strategies for routinely generated
wastes where the source is a well-defined, integral part of a production process. There are
several types of wastes among the top 100 that are either not well-defined (e.g., there are missing
data) or are not part of production processes where waste minimization opportunities involve
direct intervention or modification in the process. These include:
Waste treatment residues (source code A75)
Air pollution control device residues (source code A78)
Other pollution control or waste treatment residues (source code A89)
Other source (source code A99)
Source code not listed
Still bottoms of halogenated solvents or other organic liquids (B601)
9 The wastestreams in the top 100 wastestreams that contain benzene also contain a metal or
oeenated organic waste.
halogenated organic waste.
2-23
-------
EXHIBIT 2-12
TOP 100 COMBUSTED WASTESTREAM QUANTITIES BY REGION AND STATE
(for states with generation exceeding 1,000 tons in 1991)
Region
1
2
3
4
5
6
7
9
State
CT
MA
NJ
NY
PR
DE
MD
PA
VA
WV
AL
FL
GA
KY
NC
TN
IL
IN
MI
OH
WI
AR
LA
TX
MO
CA
Other states
Total:
Quantity
(tons/yr)
3,785
1,401
70,227
14,949
32,115
3,513
2,786
51,551
23,538
5,328
12,907
7,521
6,897
20,009
; 4,501
23,040
5,817
88,354
60,144
63,347
21,045
16,491
87,510
681,063
173,125 .
40,781
1,776
1,523,521
%of
Total
0.20
0.10
4.60
1.00
2.10
0.20
0.20
3.40
1.50
0.30
0.80
0.50
0.50
1.30
0.30
1.50
0.40
5.80
3.90
4.20
1.40
1.10
5.70
44.70
11.40
2.70
0.12
100.00
2-24
-------
Still bottoms of non-halogenated solvents or other organic liquids (B602)
To the extent that these wastes could be identified as high-priority wastes for minimization, they
would require more detailed study (and potentially a better understanding of "upstream"
processes) than most other waste categories.
Exhibit 2-13 identifies the quantities and percentages of these wastes in the top 100
combusted wastestream combinations containing metals and/or halogenated organics. As this
exhibit indicates, 35 percent (by quantity) of the top 100 combusted wastes would require
additional study in order to evaluate waste minimization. The dominant category within this set is
"Blank or Unknown Process," corresponding to BRS records where the process was not identified
by the generator or could not be tracked based on the linking of the GM and WR data sets.
EXHIBIT 2-13
WASTES REQUIRING FURTHER STUDY
Waste Category
Waste treatment (A75)
Air pollution control devices (A78)
Other pollution control or waste
treatment (A89)
Still bottoms of non-halogenated
solvents or other organic liquids
(B602)
Still bottoms of halogenated solvents
or other organic liquids (B601)
Other (A99)
Blank or Unknown process
Subtotal
Subtotal other wastes
Total "Top 100" Combusted
Wastestream Combinations
Quantity
(tons)
33,892
0
42,805
71,545
13,073
18,000
353,478
532,793
990,728
1,523,521
Percent of Top 100
Combusted Wastestream
Combinations
2.2
0
2.8
4.9
0.9
1.2
23.2
35.0
65.0
100.0
Summary of Comparison
EPA compared the top 100 wastestream combinations with all other wastestreams in order
to assess whether the top 100 were representative of combusted wastes generally. EPA found
2-25
-------
that there were some potentially significant differences between these two groups of wastes, which
could indicate directions for follow-up waste characterization work. In sum, the characteristics of
the top 100 wastestream combinations differ from the characteristics of the remaining combusted
wastestreams, in that the top 100 wastestream combinations have
a much higher average quantity per wastestream;
a much higher proportion managed on site;
Issue #4: EPA solicits comments from
reviewers on whether certain types of
combusted wastes should be the focus of
future waste characterization efforts. If
so, for which types of wastes? How could
this data be most efficiently collected?
a lower proportion of organic
liquids and higher proportion of
inorganic liquids. In particular, the
top 100 have a much higher
proportion of aqueous waste with
low solvents (B101), a substantially
higher volume of "other" organic
liquids (B219), and a substantially
lower volume of (1) concentrated
aqueous solutions of other organics (B207) and (2) non-halogenated solvents (B203);
and
more complete data (i.e., fewer blanks and unknowns in the data set) ~ this difference
means that all of the above comparisons are subject to uncertainty, particularly if there
may be a systematic bias such that wastestreams with certain characteristics may have
been more likely to have missing data.
23 LIMITATIONS
analysis.
This section lists and briefly discusses some of the limitations of the data used for this
Biennial Reporting System Data Limitations:
Most recent comprehensive data available on waste generation and management are
from 1991. Significant changes in waste management practices are believed to have
taken place since 1991. Using 1991 data does not address the potentially significant
changes in waste management practices between 1991 and 1994 due to: land disposal
restrictions (LDRs) for Third Third wastes, Phase 1, and Phase 2 wastes; expiration of
capacity variances; other federal regulations; changes in economic conditions; and
increasing awareness of environmental liabilities. As one example of an important
change, the quantity of wastes exhibiting the toxicity characteristic (TC) for organics,
and managed in incinerators or BIFs, would have increased since 1991 because of
LDRs. As a result, the characterization of the universe of combusted wastestreams is a
rough approximation.
Data used in this analysis do not reflect recent State updates. EPA wanted to make the
Phase I methodology document available for public review as quickly as possible.
Consequently, revised 1991 data submitted by States in June 1994 as part of the
2-26
-------
Capacity Assurance Planning process could not be reflected in the document. EPA
plans to utilize the updated State data when finalizing the Phase I document.
Data were missing for some kev data fields. Data were missing for some of the key
data fields used in the analysis. Missing data for these elements, along with unreported
generator and/or receiver facility IDs for facilities, made it difficult to map data from
the GM Forms to the WR Forms. This limited EPA's ability to determine the origins
of the wastes, and also made it difficult to characterize constituents and concentrations.
The quantity of waste for which key information was missing or invalid is as follows:
Waste Quantities with Missing or Invalid Information, by Attribute
Attribute
Source/Process Code
Percent of Waste Quantity with Missing Data
All Combusted Wastes
28.1
Top 100 Wastestream
Combinations with Metals and/or
Halogenated Organics
23.2
SIC Code
24.8
19.9
Form Code
12.5
5.3
Waste Code
8.2
6.1
Missing one or more
Codes
35.6
0.0
Note that process code and SIC code are the elements missing most frequently. This is
due primarily to the large set of "unmatched" off-site wastes.
Constituent Concentration Data Limitations
Constituent content and concentration estimates are rough approximations. There is
significant variability in the constituent content and concentrations of specific hazardous
wastestreams over time and across generators within an industrial sector. EPA has
developed point estimates of wastestream concentrations, for national screening
purposes, which can only roughly approximate the true range of concentrations for
particular wastestreams,
Generator Survey and other sources may not be current. EPA used the most recent
constituent content and concentration data available. However, many of the sources of
data (e.g., the Generator Survey and some of the listing background documents) are at
least five years old. Consequently, the wastestreams characterized and their constituent
content and concentrations may not correspond completely to current waste
characteristics. The extent and direction of this error is unknown. The Agency
welcomes any data from commenters that would help to update the waste
characterization data used here.
2-27
-------
Generator Survey data likely to be more accurate for metals than for organics. The
Generator Survey was designed to capture information on both metals and organics,
however, the survey format made it harder for respondents to supply information on
organics. In general, the Generator Survey data are probably more accurate for metals
than for other constituents. Wastestream combinations where the Generator Survey
was used as an information source for identifying constituents may overstate the
occurrence of metals, and understate the occurrence of organics.
2-28
-------
CHAPTERS
PRIORITIZING WASTESTREAMS AND
THE INDUSTRIAL PROCESSES GENERATING THEM
This chapter presents the methodology and results of EPA's effort to prioritize hazardous
wastestreams and the industrial processes generating these wastestreams. The first section of this
chapter discusses in detail the development of the hazard-based prioritization system. The second
section presents a summary of the results from the prioritization exercise, and the final section
outlines limitations of the system and the data used for the analysis. Highlighted throughout this
chapter are certain key issues pertaining to the prioritization methodology; the Agency is soliciting
comments from reviewers on these issues.
3.1 METHODOLOGY
3.1.1 Considerations Relevant to the Prioritization System
A number of the considerations that were important in developing the system for
prioritizing hazardous wastes are discussed below.
Addressing the goal of RCRA Waste Minimization National Plan rRWMNPI. As
discussed in Chapter 1, the stated goal of the RWMNP is to reduce the quantity and toxiciry of
hazardous waste through source reduction and then recycling (where source reduction is not
feasible). This goal indicates a focus on the hazard of wastes as generated (i.e., prioritization
based primarily on the characteristics of the waste prior to management).
Focusing on combusted wastestreams as part of Phase I of the,RWMNP. Phase I of the
RWMNP addresses hazardous wastes managed in combustion units.1 This indicates a focus on
the hazard of wastes as managed (e.g., examining the releases from combustion units and
potential exposures).
Addressing recommendations made during the November 1993 National Roundtable
discussions on waste minimization and combustion. Relevant recommendations included setting
priorities based on risk; adopting a multi-media approach that considers risks via all media;
focusing on persistent, toxic, and bioaccumulative constituents in wastestreams (e.g., metals and
halogenated organics); and encouraging movement up the waste management hierarchy (with a
clear preference for source reduction).
Meeting an ambitious schedule for Phase I of RWMNP. Phase I of the RWMNP (which
coincides with the waste minimization portion of the Hazardous Waste Minimization and
Combustion Draft Strategy) is scheduled to begin implementation this fall. This meant that an
1 Phase II of the RWMNP will go beyond hazardous wastes managed in combustion units to set
priorities for wastes managed by other practices.
2 The waste management hierarchy, described in the Hazardous and Solid Waste Amendments
(HSWA) and elsewhere, lists source reduction as the most preferred management option, followed by
environmentally sound recycling, treatment, and, finally, disposal.
3-1
-------
approach had to be developed quickly, preferably using an existing methodology that had
undergone some level of peer review. Furthermore, the approach had to be hnplementable using
readily-available data.
Selecting from a broad array of potential criteria that could be included in a prioritizatinn
system. There are a significant number of prioritization criteria that could be considered,
including the following:
Risk/hazard-based criteria
Waste quantities
Waste characteristics (e.g., constituent
concentrations and physical/chemical
properties)
Waste management practices (e.g.,
combustion)
Constituent releases
Fate and transport
Human and ecological exposure
Human and ecological toxicity
S
S
Other criteria
Protection of natural resources
(e.g., stratospheric ozone and
ground water)
Demand for waste management
capacity
Environmental justice concerns
Environmental compliance record
Technical/economic feasibility of
promoting waste minimization
Quality of life
In addition, there are different ways of aggregating and weighting the criteria. EPA desired to
develop an approach that would be suitable for national screening purposes and that would be '
applicable not only to combusted wastestreams, but to wastestreams managed by other practices as
well.
Developing a national screening tool that could potentially be understood and adapted for
use by EPA regions and state environmental agencies. EPA's national screening of wastestreams
can be viewed as just the first step in a continuing process of identifying and refining priorities for
waste minimization. Regions and states will likely refine wastestream rankings based on better
data and their own priorities.
3.1.2 Balancing the Considerations
EPA attempted to balance the considerations discussed above in developing a system for
prioritizing hazardous wastes. In reviewing potentially applicable EPA and State prioritization
methodologies (discussed in the next section), the Agency focused first on approaches that would
rank wastes based on their hazard as generated, in keeping with the broad goal of the RWMNP
to reduce the quantity and toxicity of hazardous wastes. In examining the hazard of wastes as
generated, the Agency's objective was to identify and promote source reduction for wastes that
are the most pervasive, toxic, mobile, persistent, and/or bioaccumulative, considering the major
environmental pathways of contaminant transport and exposure (air, surface water, ground water,
soils, and the food chain). This approach would potentially reduce not only the generation of
hazardous wastes, but the release of toxic constituents to all media and the subsequent exposures
of workers, the general public, and ecological receptors.
A secondary consideration in developing EPA's system for prioritizing wastes was to
identify wastes that would potentially pose the greatest risks when burned in combustion units, in
keeping with the focus of Phase I of the RWMNP on combusted hazardous wastes. EPA did not
attempt to actually estimate releases, exposures; and risk/hazard from combustion units (i.e.,
risk/hazard from wastes as managed) for the purpose of ranking wastestreams due to the following
3-2
-------
reasons: the significant data requirements and apparent lack of screening methodologies to do
this; the short schedule for Phase I of the RWMNP; and the fact that regions and/or states would
potentially be better able and more suited to conduct these analyses. Instead, the Agency decided
to focus on the characteristics of combusted wastestreams, focusing in particular on wastestreams
containing metals and/or halogenated organic compounds.
A number of participants at the National Roundtable expressed particular concern about
combustion of wastes containing metals and halogenated organic compounds. Metals are a
concern because they are not destroyed during combustion and typically end up in ash, releases to
air, and/or products (e.g., cement). All metals are persistent, and some are toxic and/or
bioaccumulative. Some metals (e.g., copper) are also believed to act as catalysts in the synthesis
of dioxins during combustion. Halogenated organic compounds are a concern since they may
contribute to formation of dioxins during combustion. Aside from the potential for reduced risks
from combustion, there may be other multimedia benefits from reducing the generation of
halogenated organic-containing wastestreams, since some halogenated organics have been
associated with depletion of stratospheric ozone and others have been liked with special ground-
water remediation problems. Furthermore, some halbgenated organics do not degrade readily in
the environment and tend to exhibit high human and ecological toxicities. Halogenated organics
are also prominent on lists of "persistent bioaccumulators" that have been derived for various
prioritization purposes.
As mentioned above, another important consideration in examining potentially-applicable
prioritization methodologies included developing an approach quickly ~ preferably using an
existing methodology that had undergone some level of peer review. Finally, given that many
current regional and state ranking systems are based on just a few prioritization criteria (e.g.,
waste quantity, constituent toxicity, and/or waste management capacity shortfalls), the Agency
wanted to limit the number of criteria considered and the complexity of the methodology. Some
of the key issues related to the. development of the prioritization scheme are listed in the
following text box.
Issue #5: Considerations and prioritization criteria relevant to developing .a prioritization
methodology. EPA solicits comments from reviewers on which considerations or prioritization
criteria should be emphasized in developing a prioritization system.
Issue #6: Emphasis on hazard of wastes as generated. EPA also requests comments on the
appropriateness of emphasizing the hazard of wastes as generated in developing a national-level
screening methodology for prioritizing hazardous wastes.
Issue #7: Focus on combusted wastestreams containing metals and/or halogenated
organics. Should the focus of the methodology, for Phase I of the RWMNP, be on setting priorities
for combusted wastestreams containing metals and/or halogenated organics? Should combusted
wastestreams containing neither metals nor halogens be addressed as well?
Issue #8: Applicability of as-generated, hazard-based methodology to combusted
wastestreams containing metals and/or halogenated organics. Given that metals are not destroyed
by combustion (and typically exit the combustion unit in ash, air releases, or product), is an as-
generated, hazard-based methodology appropriate for national screening of wastestreams containing
metals? Is it appropriate for wastestreams containing halogenated organics, or should the
methodology be modified to better reflect the hazard of these compounds as managed (e.g., through
applying a destruction and removal efficiency (ORE) factor to halogenated organics concentrations
m wastes, prioritizing based on percent halogen in waste feedstocks, focusing on wastestreams
containing dioxin precursors, or using another approach)? Should the approach be complemented
by addressing releases/transfers reported in the Toxics Release Inventory (TRI)?
3-3
-------
3.13 Review of Existing Screening, Ranking, and Prioritization Systems
As a first step toward developing a prioritization system suitable for the RWMNP, EPA
reviewed find summarized 13 existing systems or methods for screening, ranking, and/or
prioritizing chemicals, wastes, or problem areas (see Exhibit 3-1). Following the review and
summary, EPA evaluated the purposes of the various systems and their suitability for use in
support of prioritization for waste minimization.
This section briefly discusses the purposes of these 13 existing screening, ranking, and/or
prioritization methods, and their suitability for use in EPA's waste minimization prioritization
process. Summaries of these methods are provided in Appendix 7.
Purposes of the Methods Reviewed. The 13 screening, ranking and/or prioritization
methods were selected for review because they prioritized chemicals, wastes, or problem areas
based on potentially-applicable criteria. Each of these methods was developed for a distinct
purpose, and accordingly, each considered a different subset of chemicals, wastes, or problem
areas. The purposes of the various methods ranged from prioritizing treatment, storage, and
disposal facilities for possible corrective actions (National Corrective Action Prioritization System)
to targeting 17 chemicals for a pollution prevention challenge program (the EPA 33/50 program).
Applicability to the Waste Minimization Prioritization Process. The various methods, in
addition to having different purposes, also considered slightly different sets of screening/ranking
criteria, were based on different levels of scientific rigor, and relied on different types of data.
After reviewing these methods, EPA concluded that none is suitable for use as the prioritization
system for the RWMNP without some modifications. Most of the methods were screened out for
one or more reasons; examples of why methods were screened out include the following:
The Numerical Hazard Ranking Scheme for Waste Scheduling does not consider
waste quantity or ecological toxicity;
The Existing Chemicals Screening Program approach is resource-intensive and is
based on the consensus of experts regarding the riskiest chemicals rather than a
quantitative analysis that could be extended to additional constituents; and
The Risk-Based Enforcement Strategy does not consider exposure potential as a
criterion in scoring and ranking.
On balance, based on the considera-
tions discussed earlier, EPA determined that
the Superfund Hazard Ranking System, or
HRS, is the most suitable existing scoring/
ranking method to be adapted for use as a
waste minimization prioritization system for
RWMNP.3 The HRS has three major
advantages: (1) it addresses numerous hazard-
related criteria in four pathways to develop an
Issue # 9: Other applicable
prioritization systems. Are there other
methodologies in use in the United States or
in other countries that could be readily
applied to prioritizing hazardous
wastestreams?
3 The final HRS model has been published in 40 CFR Part 300 Hazard Ranking System; Final Rule, 55
Federal Register 51532, December 14, 1990.
3-4
-------
Exhibit 3-1
Existing Screening, Ranking, Prioritization Systems Reviewed
System
Arizona Waste Minimization Project Screening
Process
Chemical Use Clusters Scoring Methodology
EPA 33/50 Program Targeting Process
EPA Regional Comparative Risk Ranking
Program
Existing Chemicals Screening Program
Industrial Pollution Prevention Opportunities for
the 1990's Screening Process
National Corrective Action Prioritization System
(NCAPS)
Nonhazardous Industrial Waste Targeting and
Pollution Prevention Project
Numerical Hazard Ranking Scheme for Waste
Scheduling
Risk-Based Enforcement Strategy (RBES)
Superfund Hazard Ranking System (HRS)
Toxics Release Inventory (TRI) Environmental
Indicators Methodology
Agency/Office
EPA Office of Waste Programs Enforcement
(Region IX)
EPA Office of Pollution Prevention and Toxics
EPA Office of Pollution Prevention and Toxics
EPA Office of Policy Planning and Evaluation
EPA Office of Pollution Prevention and Toxics
EPA Office of Research and Development
EPA Office of Solid Waste
Minnesota Office of Waste Management
EPA Office of Solid Waste
EPA Office of Health and Environmental
Assessment
EPA Office of Solid Waste and Emergency
Response
EPA Office of Pollution Prevention and Toxics
Toxics Release Inventory Risk Screening Guide EPA Office of Pollution Prevention and Toxics
assessment of threats to humans and the environment; (2) it is among the most carefully
developed and most widely applied targeting schemes that is relevant to wastes; and (3) it is the
most thoroughly peer-reviewed targeting scheme among those reviewed (having been reviewed by
the EPA Science Advisory Board and the National Academy of Sciences). Furthermore, EPA
determined that the HRS could be applied quickly because it required limited modifications and
relied on readily-available data (e.g., hazard-related data had already been compiled in the
Superfund Chemical Data Matrix or SCDM).
3.1.4 Prioritization System Developed Based on the HRS
EPA determined that, at a minimum, the desired prioritization system had to reflect
hazard-based rankings of the wastestreams; therefore, it needed to consider both inherent toxicity
and potential for exposure, i.e., each wastestream had to be scored based on criteria related to
toxicity and exposure potential. For waste minimization prioritization, the toxicity criterion is
meant to measure the inherent threat of a particular wastestream, i.e., the potential for its
3-5
-------
constituents to cause adverse effects to human and ecological receptors in the event of exposure
(e.g., during handling or through combustion emissions). The exposure potential criteria are
meant to measure the extent to which the waste's constituents may be released to the
environment (reflected by waste quantity) and the potential for its constituents to be mobile, to
persist in the environment, and to accumulate in plant and animal tissue, potentially leading to
exposures.
The Agency determined that the waste characteristics factor category of the HRS provided
a suitable foundation for modeling the human and ecological toxicity and exposure potential of
hazardous wastes via several pathways. EPA modified the HRS waste characteristics factor
category slightly in developing the methodology for prioritizing wastestreams for waste
minimization (referred to as the "modified HRS approach" below), in order to better discriminate
between hazardous wastestreams. Differences between the modified HRS approach and the HRS
waste characteristics factor category (the "original HRS approach") are discussed below after
presentation of the modified HRS approach.
Modified HRS Approach for Scoring and Ranking Wastestreams
Steps in the modified approach for scoring wastestreams can be summarized as follows:
Step 1: Estimate Constituent Mass. Based on concentration of each constituent (in ppm)
and the volume of the wastestream, estimate the mass of each constituent in units of pounds.
Step 2: Determine Constituent Pathway Score. Select the highest pathway score for the
constituent, reflecting the most hazardous pathway or threat. The pathways and factors used to
derive the pathway scores are shown in Exhibit 3-2.
Step 3: Calculate Constituent Hazard Score, using the following formula:
Constituent = Constituent
hazard score mass
x Constituent pathway
score
Step 4: Determine Wastestream Hazard Score. Select the highest among the constituent
hazard scores as the wastestream hazard score.
Relationship of Modified HRS Approach to Original HRS Approach
EPA's modified approach relies on the factors and pathway scores that have been
developed as part of the HRS algorithm. In its complete form, the HRS model is used for
scoring abandoned hazardous waste sites by evaluating four pathways, i.e., ground water migration,
surface water migration, and soil exposure. (The surface water and soil pathways consist of
"subpathways" or "threats" that are scored where relevant.) Each of these pathways is scored
based on three primary criteria called "factor categories," one of which is waste characteristics.4
Individual scores are assigned to each of these factor categories based on a number of subcriteria,
4 Two other factor categories - likelihood of exposure/release and targets - were not employed in EPA's
modified approach for prioritizing wastestreams.
3-6
-------
Exhibit 3-2
Factors Used to Calculate Pathway Scores
Pathway
Ground Water Migration
Pathway
Surface Water Migration
Pathway
Soil Exposure Pathway
Air Migration Pathway
Factors for Calculating Pathway Score3
» Toxicity * Mobility
Drinking Water Threat
» Toxicity * Persistence
> Toxicity * Persistence
Human Food Chain Threat
> Toxicity * Persistence
» Toxicity * Persistence
Environmental Threat
> Ecosystem Toxicity *
> Ecosystem Toxicity *
Bioaccumulation
> Toxicity
> Toxicity * Mobility
* Mobility19
* Bioaccumulation
* Mobility15 * Bioaccumulation
Persistence * Bioaccumulation
Mobility5 * Persistence *
a The term "pathway score" corresponds to the toxicity/combined factor value derived in the original HRS.
b Mobility is included whenever a ground water-to-surface water pathway is relevant.
called "factors". The waste characteristics factor category includes the following factors:
Hazardous waste quantity factor
Human or ecological toxicity factors
Mobility, persistence, and/or bioaccumulation (or ecosystem bioaccumulation)
potential factors.
The hazardous waste quantity factor is evaluated and used individually. The remaining factors,
although evaluated individually, can be combined mathematically to obtain "combined" factor
values. For example, although toxicity, mobility, and persistence are evaluated individually, the
factor values can be combined mathematically to obtain a toxicity/combined factor value.
The relationship between the elements in EPA's. modified HRS approach and the
elements in the original HRS approach is indicated below, along with key differences:
3-7
-------
This element in
EPA's modified
approach...
is analogous to this element in the original HRS approach
Constituent mass
Hazardous waste quantity factor. The hazardous waste quantity factor
value in the original HRS is based on the mass of all constituents
combined; the value is assigned based on which range of mass values (as
determined from a table in the HRS) the,combined mass falls in.
Pathway score
Toxicity/combined factor value. The toxicity/combined factor value is
used without modification as the constituent pathway score in EPA's
modified HRS approach.
Constituent hazard
score
There is no direct analog in the original HRS, which estimates hazard
based on total mass across constituents and highest pathway value
rather than calculating a value for each constituent.
Wastestream
hazard score
Waste characteristics factor category value. The waste characteristics
factor category value in the original HRS approach is calculated by
multiplying the hazardous waste quantity factor value times the highest
toxicity/combined factor value across all constituents in the waste (i.e.,
the combined mass of all constituents in the waste is multiplied times
the highest pathway score for any constituent in the waste). EPA
modified this approach for prioritizing hazardous wastestreams so that
constituents with very high toxicity/combined factor scores but very low
mass (e.g., mercury) would not tend to artificially dominate wastestream
rankings.
In both the modified approach and the original HRS approach, each of the factors (i.e.,
[human] toxicity, ecosystem toxicity, persistence, mobility, bioaccumulation potential, and
ecosystem bioaccumulation potential) are evaluated individually based on a constituent's
properties. Procedures for evaluating the factors and the types of data considered are explained
in the HRS Final Rule;5 a brief summary is presented in Exhibit 3-3. Factor values derived
based on constituent properties can then be combined mathematically to obtain combined factor
values. HRS pathway scores that EPA used for the prioritization approach ace listed in
Appendix 8.
Scoring and Ranking Industrial Processes
EPA also modified the HRS-based scoring approach to score and rank industrial processes
generating the priority hazardous wastestream combinations. EPA calculated a score for each
wastestream combination, defined by a unique combination of RCRA code set, waste form, SIC
of generator, and source. The Agency then summed the hazard scores for each individual SIC
Code/Source Code combination to derive the SIC/source hazard score. Then, EPA ranked the
unique SIC Code/Source Code combinations according to the derived scores. In essence, the
40 CFR Part 300 Hazard Ranking System; Final Rule, 55 Federal Repster 51532, December 14, 1990.
3-8
-------
EXHIBIT 3-3
DERIVING FACTOR VALUES IN THE HRS
Toxicity
» The human toxicity factor values for hazardous constituents are established based on cancer
slope factors (SFs) and the carcinogenic weight-of-evidence classification, noncancer reference
doses (RfDs), and where appropriate, acute LC50s and LD50s (see Table 2-4 in 55 Federal
Register 51532 for values to be assigned to the toxicity factor).
» The ecosystem toxicity factor value is assigned for the constituent from Table 4-19 in 55 Federal
Regster 51532 based on the following data hierarchy:
EPA chronic Ambient Water Quality Criteria (AWQC);
EPA chronic Ambient Aquatic Life Advisory Concentrations (AALAC);
EPA acute AWQC;
EPA acute AALAC; or
Lowest LC50 value for the constituent.
Mobility, Persistence, and Bioaccumulation/Ecosystem Bioaccumulation Potential
* A ground water mobility factor value is assigned to each constituent (for the specific type of
aquifer being evaluated) based on its water solubility and distribution coefficient (Kj).
(Inorganic constituents are evaluated based on KjS only.) Table 3-8 in 55 Federal Register
51532 lists mobility factor values that correspond to the water solubility and Kd values. An air
mobility factor value for gaseous hazardous substances is derived based on vapor pressure (see
Table 6-11 in 55 Federal Register 51532 for assigning the air mobility factor values).
* The persistence factor is assigned a value based primarily on the half-life of the hazardous
constituent in surface water and secondarily on the sorption of the constituent onto sediments
(see Table 4-10 in 55 Federal Register 51532 for correspondence between half-lives and the
persistence factor score). The half-life in surface water is defined as the time required to reduce
the initial concentration in surface water by one-half as a result of the combined decay
processes of biodegradation, hydrolysis, photolysis, and volatilization.
* The human bioaccumulation potential factor value is derived for each constituent based on the
following data hierarchy: (a) bioconcentration factor (BCF) data; (b) log K^ data; or (c)
water solubility data. Only data relevant to aquatic food chain organisms are used. The factor
value is assigned according to Table 4-15 in 55 Federal Register 51532.
+ The ecosystem bioaccumulation potential factor is evaluated in the same way as the
bioaccumulation potential factor, with two exceptions:
BCF data for all aquatic organisms (not just aquatic human foodchain organisms) are
used; and
BCF data that correspond to the type of water body in which the sensitive
environments are located are used.
3-9
-------
score for each SIC Code/Source Code combination reflects the hazard of all the wastestream
combinations (that are assigned hazard scores in the preceding exercise) that it generates.
3.2 DRAFT RESULTS
This section describes the draft results from the scoring and ranking analysis, Grst on the
basis of wastestream combinations, and then aggregated based on origins of the wastes. Note that
hazard scores are represented by very large numbers (e.g., the highest score is 7.1 x 1013). The
numeric hazard scores do not correspond to any absolute measure of the magnitude of hazard or
risk: only the relative difference between the scores is significant (see also the limitations
discussion).
3.2.1 Scores and Ranks for Wastestream Combinations
The list of top 100 wastestream combinations, ranked by their hazard scores is presented
in Exhibit 3-4. For each wastestream combination, the exhibit also shows the constituent on
which the hazard score is based ("hazard-driving constituent"), and the rank for each wastestream
combination based on waste quantity alone. The range of scores is quite broad, from about
5.1E+06 to 7.1E+13,6 and the total hazard score (i.e., the sum of the wastestream hazard scores
across all 100 wastestream combinations) is 1.9E+14. The results in Exhibit 3-4 illustrate three
key points:
(1) Most of the hazard - almost 85 percent of the total hazard score is accounted
for by the top five wastestream combinations. Three of these five wastestream
combinations belong to SIC 2869 (Industrial Organic Chemicals) and Source Code
A33 (Product Distillation);7 ;
(2) Although there is a very large range in the scores (almost seven orders of
magnitude), 73 of the 100 fall within a two order of magnitude range, between
1E+10 to 1E+12.8 Thus, as.measured by the scoring system, there is a fairly large
set of wastes with a similar degree of hazard, and smaller sets of relatively high-
hazard and low-hazard wastes that are distinctly different;
(3) The hazard of a given wastestream combination is not driven by waste quantity
alone, but reflects both the waste quantity and the hazard of the waste
constituents. The "volume rank" column in Exhibit 3-4 shows that the five top-
ranked wastestream combinations are not the top "volume-drivers," and the highest
quantity wastestream combination ranks as No. 17 in terms of hazard.
For scientific notation, this report uses a convention used frequently in computer programming, i.e., the
digits following a capital E represent the exponent to the power of 10. For example, 2E+02 represents 2 x
10* or 200.
7 Appendix 2 presents BRS code descriptions for all codes used in the BRS data forms.
8 In fact, the scores appear to exhibit a log-normal distribution, with the geometric mean close to the
median score (8.7E+10).
3-10
-------
EXHIBIT 3-4
TOP 100 WASTESTREAM COMBINATIONS, RANKED BY HAZARD SCORES
Rank
1
2
9
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
. 31
32
:33
34
- ; 35
36
37
38
39
40
41
Wasteatream Combination
D001 F001 FQ02FQQ3 rmMJ|ii«98*MP03 UQ19 U028
0002 0006
K022 . . :-.
0001 D002 0019 0032 0033 0034 D039 F002
0001 D007 0008 D018 0022 0026 DD27 0028 0033 0036
0001 0002 0003 F002 F020 F024 KOI 7 K018 K020 K028
F003F005 "". ' ..YYY7:>:*:V:,Yv.;.:Y: . 1 Y 7
0001 0008 F003 F005
0001 DQ02 : , ; -Y-:-.0-'v .:,-
Unknown
00010002 ...: :. :
0001 001 8 001 9 0039 F024
D001D028F037F038
K002
0001 0005 0006 0007 0008 0018 0026 P035 F001 F002
0019 0022 0032 0039 0043 KOI 8 K020
0001 0002 U008U1 13
D001K013U003
0001 F001 FOQ2 F003 -:.'
0001 0008
K048K049K051 : .
F003 F005
D001F003F005 : :
0001 0004 0005 0006 0007
0001 0002 F002 F003 F005 U002 U012 U031 U044 U080 ::
0001 0002 0003 0008 0018 0023 0024 0025 0026
0001 0010 DQ19 P022 0028 : :
K051
0001 0002 0007 001 8 0081 FQ02 F003 F005 : ;
0001 0002 0003 0018 0026 0035 F002 F003 F004 F005
D001 0004 0005 0006 DQQ7 OP08 D009 00)0 OQ11 P016
0001 F003 F005
0001 D002 :l: i
K049
0001 0004 0005 0006 0007 0008 0009 0010 001 1 0018
0001 0005 0006 0007 0008
001 8 F037 F038 K048 K049 K050 K051
0001 0004 0005 0006 0007 0008 0009 0010 0016 F001
0001 0002 0003 0004 0005 0006 0007 0008 0009 0010
0001 0004 0005 0006 0007 0008 0010 001 1 0018 0035
0001 D002 0007 001 8 0021 F002 F003 F005
SIC
Code
2869
2833
2869
2869
9999
2821
Unkwn
4953
2869
Unkwn
2869
2869
2911
2865
Unkwn
2869
2069
2869
Unkwn
2821
Unkwn
2819
Unkwn
Unkwn
2834
2869
2869
2911
2065
2869
Unkwn
Unkwn
2019
2911
Unkwn
7389
2911
7389
4953
2899
2865
Source
Code
A33
A32
A33
A33
A99
A37
Unkwn
A73
A31
Unkwn
A35
A74
A89
A33
Unkwn
A33
A33
A33
Unkwn
A33
Unkwn
A
Unkwn
Unkwn
A37 -
A33
A3? »
A89
A31
A33
Unkwn
Unkwn
A37
A75
Unkwn
A89
A75
A71
A99
A89
A34
Form
Code
8219
B207
8606
B219
8219
8219
8219
B203
B20r
B206
8219
8202
8205
B203
8219:
8219
8101
B219
B204
B602
Unkwn
B
B203
B204
B2Q1;
B219
B202
8603
0204
8219
B202,:::
B204
8219
B202
8202
8204
B603
B219
81 14
B204
8204
Volume
(Tons)
14,217
3.724
23.281
3,866
7.001
48,039
17,218
4.080
3.073
84.191
95,042
26,708
6.785
6,554
31.348
3.132
189,624
5,554
10,782
13,395
3,393
6,101
5,692
22.251
:4,163
10.025
8,416
6.217
4.701
14,194
6,691
8,747
15,997
3,316
5.565
10,883
10,580
4.743
4.564
4.531
4.315
Hazard -Driving
Constituent
Bfc (2~ethylhexyt) phthajate
Cadmium
Fluoranthene
Hexachlorobutadiene (hexachloro-1 ,3-buta
Hexachlarobutadiene(hexachlara-Tl.3-buta
Tetrachlorobenzene
Mercury ':-.
Lead
Hexachlorocyclopantadiena
BenzD(a)anthracene
Aniline ;
Hexachlorobutadiene (hexachloro-1 ,3-buta
Benzo(a)anthreceno ;
Lead
Cadmium ; - ::.v . ; ';-;- -._.': '.
Hexachlorobenzene
Acrolvln . : :..._,:. . .,-...
Acrolein
Selenium .: : ..-., .... : .'
Lead
Mercury . ...
Lead
Uad- - ...-_.: . - .. , '
Cadmium
AniHne , ; .
Benzene
Benzene :..;£:.,; :' -: -. -
Lead
Benzene
Benzene
MeroUfy
Lead
Aniline ,
Bto (2-ethylhexyl) phthalate
Benzene ; " . .
Cadmium
Benzene
Mercury
Mercury
Mercury
Benzene
Wastestream '
Combination Cum.
Score Percent
7,09E*13
3.72E+13
2,32E'»'t3
1.93E+13
1.05E+13
4.79E+12
2.58E-H2
2.43E+12
1.93E-J-1?
1.68E+12
1.42E+12
1.33E+12
6.77e+11
6.54E+11
6.26E-H1
6.256+11
5.67E-H1
5.54E+11
8,886+11
5.35E+11
5.08E+11
4.57E+11
: 4.54E+11
4.44E+11
4.15E+11
3.76E+11
3.36E+11
2.92E+11
2.86E+11
2.83E-H1
2.03E+11
2.62E+11
2,396^11
2.32E+11
2,22E. - 1
93
-v .: «S
44
-,-::. 134
84
'..f:.- 90
25
116
27
62
83
102
:: . F?f*
42
79
60
37
135
92
" 53
57
103
106
107
11|
3-11
-------
EXHIBIT 3-4 (continued)
TOP 100 WASTESTREAM COMBINATIONS, RANKED BY HAZARD SCORES
Rank
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
. 69
70
71
72
73
74
75
76
77
78
79
80
81
82
W»ttestream Combination
D001 D007D008D018
D001 0005 0006 0007 DQ09; ^ > * A r "-
0001 0018 K048 K049 '
Unknown "' :Xx^. ;:.; .'.:=..- --'
D001 F024
K048 - ',.*,: ' ;.,> .::;> , - . .-
D001 0004 D005 D006 0007
D001D002 : ' :S;^./-:::'^C^..;4 /. .'. . .. :,-^
D005 D006 0008 F001
D018D038K022K083.? ,< ;;. : : ;f. . V ;;;
0001 D005 0006 0007
00010011 00180021 0022 .
0001 F001 F003 F005
000100020007
0001 0005 0006 0007 0008 F001 F002 F003 F004 F005
0001 0005 0006 0007 0008 F003 F005
0001 0002 0005 0006
0001 0002 0019 0022 0027 DQ28 0029 0032 0033 DQ34,w
0001 0006 0008 F002
F001FQ02FQ03F005 :
0001 0005 0006 0007 0008 0011 0022 0035 0039 F001
0001 0002 D007 0008 0018 D035 F001 F003 FQ05 UOQ9 : /
0001 F001 F002 F005
0008 Ji;v.:.U':v ^- =.. :
0001 F004
0001 0007 POOS FOOt Fp02F003Fq05 . :
K022
KQ22 - ..:- ::.:,':;; v.- :, :-.: \>,-. --^::-v
0001 0002 0007
D001F001F002F003
0001 0002 F003 F005 K038 P094
0001 0002 0003 DOQ4 D005 D006 D007 0008 0009 D010
K017K019K020
0001 : ->:_- . ; ..::..-:.:.:-- ?'. . . ' , . :,£:
0001 0018 0043 F001 F002 F003 F004 F005
F001F002F003 :
K022
D001F003FOD5 .. :
0002 0021 0028 F003 F005
0001 : ^:--. : ;,:
0001
SIC
Code
2911
Unkwn
2911
3221 '
2819
2911.
Unkwn
2869:.
4953
2865:
Unkwn
3861:
Unkwn
2869.:;
7389
2821
4953
2869
Unkwn
Unkwn
Unkwn
2869
Unkwn
Unkwn
2821
9999
2865
2869
2869
2899V
2879
2869 :
2869
2512
Unkwn
Unkwn
2865
30.53
2879
2869
2869
Sourc*
Code
A89
Jnkwn
Unkwn
A54 ;.-.
A33
A75
Unkwn
A33 -=
Unkwn
* "'. .- ':;.;"
Unkwn
A.49:;i;-.
Unkwn
AS3;;v.v
A71
A73,
Unkwn
A9.9 ,
Unkwn
Unkwn
Unkwn
A37 :
Unkwn
Unkwn:
A33
Unkwn
A33 .
A33 .
A33
A89
A37
A33
A33
A92
Unkwn
Unkwn
A35
A56
A37
A35
A35
"orm
Code
B204
B407
B204
B206
B219
B503
B407
B2JI9,:
B204
6?":;;
B204
B204;i:,
B204
eeoa
B206
8602 , .
B204
B494,:
B403
8204,,
Unkwn
B219
B204
Unkwn
B602
B202r
B602
B219
B219
B204:
B101
BIOS
B601
B403
B204
Unkwn
B602
B403 :
81 01
B207
B606
Volume
(Tons)
8,564
7,826
3.669
7,914
14,893
19,996
4,509
7,412
4,348
17.303
3.775
: 9.390
5,956
36.709
3,518
: 3.410
3.295
6,435
3.168
6,975
3.124
5,979
10.929
^5,357
3,990
: 4.866
9,432
10.946
16.099
5.825
35,136
13,182
13,073
4,322
15,509
4,822
4.609
3,465
130.948
;tP^82
3.175
rlazord- Driving
Constituent
Benzene
Cndmium
Benzene
U«d
1 ,3-Oichloropropene
B«nzo(a)pyr«n9 : :. .
Cadmium
Benzene - =:.
Cadmium
Phenol ::.-;':...' .. -, '--'
Cadmium
Benzene ..: . ... .
Selenium
Xyltne .-.:.: '.- . . .;.:
Benzo(a)anthracene
Cadmium ".: '.-.::.. : , : ..
Cadmium
Hexftchlorqbutadisne (hexachtorp-l ,3^but«
Cadmium
S«lfnKim.-y^--v:':.;i,s;-:\...... .';*'.. .-.. .
Cadmium
U»d:S-k -..-.. ';.-.'.:-;. ;:;:-:-- ,:-
Acrylonitrile
U«K»^::V::^ -; ?';'*. !«:- .'. -. . .'
Phenol
U»d V--.:":?-:-.i--'> .' . ' . - .- i
Phenol
Phenol: ,-.;-i>;; ,,*>.-- . .,..
Xylene
SsJeniHmV: : : .
Xylene
Xylen*
1,1,2-Trfchloroethane
\*rt.. ""<'" ->: - .
Carbon tetrachlorlde
Selenium: £:: ;:;::.-
Phenol
Xylen*_:. :-.: - -: : ' ' -.--;
Chlorobenzene
Wit* :..k- ; .
Banzene
Wastestraam
Combination
Score
1.71E+11
i.$«e*ii
1.46E+11
1.186*11
1.04E+11
9.98E-f10
9.00E+10
8.87E+10
8.68E+10
8.63E+10
7.53E-f10
7.49E-MO
7.43E+10
7.32E+10
7.02E+10
6.80E+10
6.57E+10
6.42E-HO
6.32E+10
6.266+10
6.23E+10
5.67E+10
5.45E+10
5.34E+1D
5.18E+10
4.85E*10
4.71 E+ 10
94MS-I-10
3.21 E+ 10
8,915*10
2.80E+10
2,63E*10
2.61E+10
a,596*10
2.48E+10
2.416*10
2.30E+10
2.28E+10
2.22E+10
2.14E+10
1.27E+10
3um.
Percent
98.73%
:"^$'Mll%-.
98.88%
-m$$*
99.00%
':M$%
99.10%
v>?^i5%
99.19%
: 99.24%
99.28%
99.32%
99.35%
,89.39%
99.43%
s 99.46%
99.50%
::-.: '99-63%
99.57%
:: 99.60%
99.63%
99.65%
99.69%
/; 99,72%
99.74%
99,77%
99.79%
99,81%
99.83%
\:-99,84%
99.86%
99.87%
99.89%
; 99.90%
99.91%
99,93%
99.94%
. 89.99%
99.96%
99.97%
99.98%
Volume
Rank
61
^Kf 68
126
v^ '67
39
**, -! 26
108
.;>?:; .,..70
ill
.:: qa
: :' :« W
124
**-^ ..59
86
- ' 14
129
J,,v .:133
136
:/t . 80
138
::4.,:'73
140
'.S.'-.: 91
52
f.-:;; 95
119
A:'-.- 99
58
":^::- 84
36
:^.: 89
15
:>-\: 45
46
'fv>:,. -.112
38
* 101
105
; 131
2
66
137
3-12
-------
EXHIBIT 3-4 (continued)
TOP 100 WASTESTREAM COMBINATIONS, RANKED BY HAZARD SCORES
Rank
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Wastestream Combination
D001 ';.. /:.:.:; :/.
D001 F001 F002 F003 F005
0001 0002 -Vs.: -I;:,-;;,: :.,.'.:-
D001 F002 F003 F005
DOQ1FD02FQ03FOQ5 : i; :: : : :
0001 D022
FQQ2F005 . f^:':^-'^*': afe: . --- -
D001 0002 0003
0002 -:". - ' ' /:};-- ::./" :-:.-:>:.: . : , ' -,
0001
0001 0002 D003 0018 D02J 0023 0024 0025 0026 0035
K027
DD01 0002 0003 DOQS D018 D021 0023 0024 0025 0026
0001 0002 F003
K027
0001 F002 F003
F002
F002 F003 F005
SIC
Code
Unkwn
Unkwn
Unkwn
2384
2833
2869
2834
2879
2869
2869
2869
2865
2869
2819
2865:
2833
2879
2384
Sourca
Cod*
Unkwn
Unkwn
Unkwn
A37
A35
A37
A37
A37
A09 i
A35
A33
A33
Unkwn
A
A33
A35
A35
A37
Form
Cod*
Unkwn
B202
Unkwn
B101
6101
B202
B101
B102
B207
B219
B219
B409
Unkwn
B
B403
B101
8101
B101
Volume
(Tons)
25.371
5,922
3.477
18.747
26,264
3,414
28,640
27,247
8.001
12,842
: 7.418
11,123
6.075
5,323
4,457
18,154
37,447
6,414
Hazard -Driving
Constituent
1,2-Ofchloropropane
Carbon tetrochloride
Xylene
Benzene
Toluene
Chbroform
Xylene
Selenium
Copper
Mercury
Chbrobenzene
Ethyl benzene
Chbrobenzene
Mercury
Ethyl benzene
Methylene chloride
Methytene chloride
1 ,1 ,2-Trichloroethane
Wastestream
Combination
Score
1.01E-MO
9.45E+09
6 94E+09
5.61E+09
21ftf?JU(lQ
1.16E+09
1.14E409
8.16E+08
7.98E+08
6.41E+08
5.03E+OS
4.44E+08
4,12E+08
1.06E+08
8.89E+07
5.43E+07
t,79E+07
5.12E+06
1.909E+14
Cum.
Percent
99,98%
99.99%
9fl99%
100.66%
imi nnM.
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%
Volume
Rank
23
87
1
-------
Because much of the total score is dominated by the top five wastestream combinations,
and the subsequent discussion of waste origins is driven by the scores of these wastestream
combinations, some of their principal characteristics are described below.
D001 F001 F002 F003 F005 U001 U002 U003 U019 UQ28: "other" organic liquid:
from product distillation in the industrial organic chemicals industry. Based on the
waste codes, EPA characterized the top-ranked wastestream combination as
consisting primarily of off-specification commercial products and spent solvents.
The Agency determined that 13 different constituents, including eight halogenated
organics, were likely to be present in the wastestream combination in
approximately equal concentrations (assumed to be 50,000 ppm for each
constituent). Of these, bis 2-(ethylhexyl) phthalate received the highest
constituent hazard score.
D002 D006: concentrated aqueous solution of other organics: from product
filtering; from the medicinal chemicals and botanical products industry. EPA
characterized the number two-ranked wastestream combination based on the
constituents and concentrations reported in the GENSUR, for an identical set of
RCRA codes and waste form. The composition of this wastestream combination
included cadmium at a concentration of 100,000 ppm, as reported in GENSUR;
cadmium received the highest constituent hazard score.
K022: organic sludge containing resins, tars, or tanv sludge: from product
distillation in the industrial organic chemicals industry. The RCRA code for this
wastestream combination indicates "distillation bottom tars from the production of
phenol/acetone from cumene." Based on constituent data from GENSUR for the
same RCRA code and SIC, EPA characterized this wastestream combination as
containing about 30 constituents. Based on the waste form tarry sludge the
Agency estimated that the polynuclear aromatic hydrocarbons (PAHs) present
would have relatively high concentrations, on the order of 10,000 ppm each.9 Of
the 30 organic and metal constituents, the highest hazard score was assigned to
fluoranthene, one of the PAHs.
D001 D002 D019 D032 D033 D034 D039 F002: "other organic liquid: from
product distillation in the industrial organic chemicals industry. This wastestream
combination includes five toxicity characteristic codes, as well as a halogenated
solvent code (F002). Based on the waste codes, the BRS notation that the
wastestream combination was the subject of a Toxics Release Inventory (TRI)
report that it contained chloropyridine, and GENSUR data, EPA characterized
this wastestream combination as containing 11 hazardous constituents plus
hydrochloric acid (assumed to impart the corrosivity characteristic). Chlct ;vndine
was assumed to have a concentration of 150,000 ppm; the other seven
Note that two other K022 wastestreams were among the top 100. One of them, generated by the same
SIC but in the form of an organic liquid, was assumed to have the exact concentrations reported in the
GENSUR (this wastestream has a rank of 69 in Exhibit 3-4). The other is generated by a different SIC, which
matched with another wastestream reported in the GENSUR, and was characterized based on constituents and
concentrations reported for the other SIC. It appears at rank 68 in Exhibit 3-4.
3-14
-------
present were assumed to have concentrations of 50,000 ppm each. The hazard-
driving constituent is hexachlorobutadiene.
D001 D007 D008 D018 D022 D026 D027 D028 D033 DQ36: "other organic liquid:
from an unspecified process in the "nonclassifiable establishments" SIC. This
wastestream combination includes nine toxicity characteristic codes. Based on the
waste codes and the waste form, EPA characterized this wastestream combination
as containing the nine TC hazardous constituents, and assumed that ignitability was
imparted by one or more of these constituents. The organics present were
assumed to have concentrations of 15,000 ppm each. As with the fourth-ranked
wastestream combination, the hazard-driving constituent is hexachlorobutadiene.
The scores of the five top-ranked wastestream combinations are driven by constituents
that are non-halogenated organics (bis 2-(ethylhexyl) phthalate, fluoranthene), metals (cadmium),
or halogenated organics (hexachlorobutadiene). Exhibit 3-5 further illustrates this point, i.e., that
the top hazard-driving constituents belong to all three classes (non-halogenated organics, metals,
and halogenated organics).10 The hazard-driving constituents are ranked in Exhibit 3-5
according to their total hazard score, summed across all 100 ranked wastestream combinations.
Bis 2-(ethylhexyl) phthalate appears to account for almost 40 percent of the total hazard score;
this is consistent with the fact that it is the hazard-driving constituent for the top-ranked
wastestream combination, which has a high hazard score relative to all other wastestream
combinations. Again, the results indicate that about 86 percent of the total hazard score is due to
just four of the top-ranking constituents.
The hazard scores for 65 of the 100 wastestream combinations were derived based on two
HRS pathways: (1) surface water/environmental threat pathway, and (2) surface water/human
food chain threat pathway (both for the overland flow/flood component). Together, these two
"hazard-driving pathways," i.e., pathways for which the hazard-driving constituent received the
maximum score, account for about 96 percent of the total hazard score, across all wastestream.
combinations. Constituents are assigned pathway scores for the surface water environmental or
human food chain threat pathways based on ecological/human toxicity, persistence, and
bioaccumulation potential.
Exhibit 3-6 shows how the form codes rank according to the hazard score. Three waste
forms "other" organic liquids, concentrated aqueous solution of other organics, and resins
comprise almost 92 percent of the total hazard score (primarily because they are associated with
the top five wastestream combinations). Non-halogenated and halogenated solvents comprise
most of the remaining share of the total hazard score.
10 Note that, by definition, the top 100 wastestream combinations were selected because they contained
metals and/or halogenated organics. In addition to these constituents, the wastestreams may also contain non-
halogenated organic constituents. Depending on their relative hazard, the non-halogenated organics can
appear as the "hazard-driving constituents".
3-15
-------
EXHIBIT 3-5
HAZARD-DRIVING CONSTITUENTS, RANKED BY HAZARD SCORES
(for Top 100 Wastestream Combinations)
OBS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Constituent
Bis (2-ethylhexyl) phthalate
Cadmium
Hexachlorobutadiene
(hexachloro-l,3-butadiene
Fluoranthene
Lead
Tetrachlorobenzene
Mercury
Benzo(a)anthracene
Benzene
Aniline
Hexachlorocyclopentadiene
Acrolein
Selenium
Hexachlorobenzene
Phenol
Xylene
1,3-Dichlpropropene
Benzo(a)pyrene
Acrylonitrile
Carbon tetrachloride
1, 1,2-Trichloroethane
Chlorobenzene
1,2-Dichloropropane
Toluene
Chloroform
Copper
Ethyl benzene
Methylene chloride
Key
Other Constituent
Metal
Halogenated Organic
Other Constituent
Metal
Halogenated Organic
Metal
Other Constituent
Other Constituent
Other Constituent
Halogenated Organic
Other Constituent
Metal
Halogenated Organic
Other Constituent
Other Constituent
Halogenated Organic
Other Constituent
Other Constituent
Halogenated Organic
Halogenated Organic
Halogenated Organic
Halogenated Organic
Other Constituent
Halogenated Organic
Metal
Other Constituent
Halogenated Organic
Total
Hazard
Score
7.12e-H3
3.91e+13
3.12e+13
2.326+13
5.39e+12
4.796+12
3.906 + 12
2.43e+12
2.39e+12
2.086+12
1.93e+12
1.12e+12
7.296+11
6.25e+ll
2.416+11
2.126+11
1.04e+ll
9.986+10
5.45e+10
3.426+10
2.616+10
2.316+10
1.01e+ 10
'2.10e+09
I.16e+09
7.98e+08
5.33e+08
7.236+07
1.916+14
% of Hazard
Score
37.28
20.49
16.33
12.17
2.82
2.51
2.04
1.27
1.25
1.09
1.01
0.59
0.38
0.33
0.13
0.11
0.05
0.05
0.03
0.02
0.01
0.01
0.01
0.00
0.00
0.00
0.00
0.00
99.98
Cum. % of
Hazard Score
37.28
57.77
74.10
86.27
89.09
91.60
93.64
94.91
96.16
97.25
98.26
98.85
99.23
99.56
99.69
99.80
99.85
99.90
99.93
99.95
99.96
99.97
99.98
99.98
99.98
99.98
99.98
99.98
3-16
-------
EXHIBIT 3-6
FORM CODES, RANKED BY HAZARD SCORES
Hazard
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Form Code Description
Other organic liquids
Concentrated aqueous solution of other organics
Resins
Non-halogenated solvent
Halogenated/non-halogenated solvent mixture
Halogenated solvent
Waste oil
Unknown
Still bottoms of non-halogenated solvents
Oil-water emulsion or mixture
Aqueous waste with low solvent
Oily sludge
Concentrated solvent-water solution
Other halogenated organic solids
Other aqueous waste with low dissolved solids
Solid resins or polymerized organics
Lime sludge with metals/metal hydroxide sludge
Unknown
Acidic aqueous waste
Still bottoms of halogenated solvents
Aqueous waste with low other toxic organics
Other non-halogenated organic solids
Form
Code
B219
B207
B606
B203
B204
B202
B206
Unk.
B602
B205
B101
B603
B201
B407
B114
B403
BS03
B494
B105
B601
B102
B409
Hazarc
Score
1.13e+14
3.91e+13
2.32e+13
3.54e+12
2.97e+12
2.446+12
1.87e+12
1.21e+12
7.98e+ll
6.77e+ll
6.26e+ll
5.036+11
4.156+11
Z46e+ll
1.82e+ll
1.12e+ll
9.98e+10
6.42e+10
2.63e+10
2.61e+10
8.16e+08
4.44e+08
%0f
59.05
20.49
12.18
1.86
1.55
1.28
0.98
0.63
0.42
0.35
0.33
0.26
0.22
0.13
0.10
0.06
0.05
0.03
0.01
0.01
0.00
0.00
Cum % o:
59.05
79.54
91.72
93.57
95.13
96.41
97.39
98.02
98.44
98.79
99.12
99.39
99.60
99.73
99.83
99.89
99.94
99.97
99.99
100.00
100.00
100.00
3-17
-------
3.2.2 Scores and Ranks Based on Waste Origins
Exhibit 3-7 shows how the SIC Code/Source Code combinations rank in terms of their
hazard scores. Again, about 85 percent of the total hazard score (sum of scores across all SIC
Code/Source Code combinations) is contributed by three combinations:
SIC Code 2869 (Industrial Organic Chemicals)/Source Code A33 (Product
Distillation);
SIC Code 2833 (Medicinal Chemicals and Botanical Products)/Source Code A32
(Product Filtering); and
Non-classifiable SIC Code/Unspecified Source Code.
These constitute the combinations representing the top five wastestream combinations. The next
combination, unknown SIC and unknown source, primarily comprises non-halogenated solvents
(the seventh-ranked wastestream combination) and waste oils (the tenth-ranked wastestream
combination).
Exhibits 3-8 and 3-9 indicate how the hazard scores apportion to the SIC Codes and
Source Codes individually. These exhibits again show that overall wastestream combination
hazard is being dominated by just a handful of $IC Code and Source Code combinations.
Finally, most of the ten top-ranked wastestream combinations represent a small number of
BRS records of wastestreams at a few facilities, as shown in Exhibit 3-10. The nine top-ranking
wastestream combinations are focused in 20 or fewer facilities; slightly less than half of these
facilities manage their wastes on site. This indicates that for the nine highest-hazard wastestream
combinations, there is an opportunity to focus the next phase of the prioritization and waste
minimization effort within a relatively small set of facilities. This may allow for site-specific data
collection and evaluation of waste minimization potential. The tenth-ranked wastestream
combination, waste oils, is generated by a much larger set of facilities, many of whom ship waste?
off site.
Also, the draft results indicate that a majority of the nine top-ranking wastestream
combinations are focused primarily in the States of Texas, Connecticut, Pennsylvania, and
Virginia. Three of these states account for a large percentage of the total hazard score across all
wastestream combinations, i.e., Texas (=53 percent), Connecticut (» 20 percent), and
Pennsylvania (3 13 percent); see Exhibit 3-11. A detailed listing of states and regions
corresponding to the top 100 ranked wastestream combinations is provided in Appendix 9.
3.23 Summary
EPA emphasizes that this report presents draft results, and views this effort as a work in
progress rather than a final analysis. The Agency is interested in receiving comments on how the
methodology for prioritization can be improved and how better data for use in the scoring and
ranking can be obtained. The draft results in this report should be viewed in light of the
following points:
EPA's primary objective in developing the prioritization methodology is to create a
useful overall framework for national-level screening analysis, that while initially
3-18
-------
EXHIBIT 3-7
SIC CODE/SOURCE CODE COMBINATIONS, RANKED BY HAZARD SCORES
1 lazard
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
SIC Code Description
Industrial Organic Chemicals, N.E.C
Medicinal Chemicals and Botanical Products
Nonclassifiable Establishment*
Unknown
Plastics Materials, Synthetic Resins, and Nonvulcanizable Elastomers
Refuse Systems
Industrial Organic Chemicals, N.E.C.
Industrial Organic Chemicals, N.E.C.
Industrial Organic Chemicals, N.E.C.
Petroleum Refining
Cyclic Organic Crudes and Intermediates, and Organic Dyes and Pigments
Plastics Materials, Synthetic Resins, and Nonvulcanizable Elastomers
Petroleum Refining
Industrial Inorganic Chemicals, N.E.C.
Pharmaceutical Preparations
Industrial Organic Chemicals, N.E.C.
Cyclic Organic Crudes and Intermediates, and Organic Dyes and Pigments
Business Services, N.E.C.
Industrial Inorganic Chemicals, N.E.C.
Business Services, N.E.C.
Chemicals and Chemical Preparations, N.E.C.
SIC
Code'
2869
2833
9999
Unk.
2821
4953
2869
2869
2869
2911
2865
2821
2911
2819
2834
2869
2865
7389
2819
7389
2899
Source Code Description
Product distillation
Product filtering
Other
Unknown
Spent process liquids removal
Solvents recovery
Product rinsing
By-product processing
Incineration/Thermal treatment
Other pollution control or waste treatment
Product distillation
Product distillation
Wastewater treatment
Unknown
Spent process liquids removal
Spent process liquids removal
Product rinsing
Filtering/screening
Spent process liquids removal
Other pollution control or waste treatment
Other pollution control or waste treatment
Source
Code
A33
A32
A99
Unk
A37
A73
A31
A35
A74
A89
A33
A33
A75
Unk
A37
A37
A31
A71
A37
A89
A89
Hazard
Score
1.16e+14
3.72c+13
1.05e+13
8.34e+12
4.79e+12
2.43e+12
l'.93e+12
1.46e+12
1.33e+12
1.14e+12
7.01e+ll
5.86e+ll
5.42e+ll
4.57e+ll
4.22e+ll
3.94e+ll
2.86e+ll
2.59C+11
2.39e+ll
2.17e+ll
2.10e+ll
%of
Hazard
60.85
19.47
5.49
437
2.51
1.28
1.01
0.76
0.70
0.60
0.37
0.31
0.28
0.24
0.22
0.21
0.15
0.14
0.13
0.11
0.11
Cum % of
Hazard
60.85
80.32
85.81
90.18
92.69
93.%
94.98
95.74
96.44
97.03
97.40
97.71
97.99
98.23
98.45
98.66
98.81
98.95
99.07
99.19
99.30
3-19
-------
EXHIBIT 3-7 (continued)
SIC CODE/SOURCE CODE COMBINATIONS, RANKED BY HAZARD SCORES
Hazard
Rank
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
SIC Code Description
Refuse Systems
Cyclic Organic Crudes and Intermediates, and Organic Dyes and Pigments
Refuse Systems
Petroleum Refining
Glass Containers
Industrial Inorganic Chemicals, N.E.C.
Cyclic Organic Crudes and Intermediates, and Organic Dyes and Pigments
Photographic Equipment and Supplies
Plastics Materials, Synthetic Resins, and Nonvulcanizable Elastomers
Industrial Organic Chemicals, N.E.C.
Pesticides and Agricultural Chemicals, N.E.C.
Nonclassifiable Establishments
Wood Household Furniture, Upholstered
Cyclic Organic Crudes and Intermediates, and Organic Dyes and Pigments
Gaskets, Packing, and Sealing Devices
Medicinal Chemicals and Botanical Products
Industrial Organic Chemicals, N.E.C.
Industrial Organic Chemicals, N.E.C.
Pesticides and Agricultural Chemicals, N.E.C.
SIC
Code
4953
2865
4953
2911
3221
2819
2865
3861
2821
2869
2879
9999
2512
2865
3053
2833
2869
2869
2879
Source Code Description
Other
Product solvent extraction
Unknown
Unknown
Oil changes
Product distillation
Unknown
Other non-surface preparation processes
Solvents recovery
Other
Spent process liquids removal
Unknown
Routine cleanup wastes
By-product processing
Discontinue use of process equipment
By-product processing
Clean out process equipment
Unknown
By-product processing
Source
Code
A99
A34
Unk
Unk
A54
A33
Unk
A49
A73
A99
A37
Unk
A92
A35
A56
A35
A09
Unk
A35
Hazard
Score
1.82e+ll
1.72e+ll
1.53e+ll
1.46e+ll
l.lSe+11
1.04e+ll
8.63C+10
7.49e+10
6.80e+10
6.42e+10
S.lle+10
4.85e+10
Z59e+10
2.30C+10
2.28e+10
2.15e+09
7.98e+08
4.i2e+08
1.79e+07
%of
Hazard
0.10
0.09
0.08
0.08
0.06
0.05
0.05
0.04
0.04
0.03
0.03
0.03
0.01
0.01
0.01
0.00
0.00
0.00
0.00
Cum % of
Hazard
9939
99.48
99.56
99.64
99.70
99.75
99.80
99.84
99.87
99.91
99.94
99.96
99.97
99.99
100.00
100.00
100.00
100.00
100.00
3-20
-------
EXHIBIT 3-8
SIC CODES, RANKED BY HAZARD SCORE
Hazard
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
SIC Code Description
Industrial Organic Chemicals, N.E.C.
Medicinal Chemicals and Botanical Products
Nonclassifiablc Establishments
Unknown
Plastics Materials, Synthetic Resins, and Nonvulcanizable Elastomers
Refuse Systems
Petroleum Refining
Cyclic Organic Crudes and Intermediates, and Organic Dyes and Pigments
Industrial Inorganic Chemicals, N.E.C.
Business Services, N.E.C.
Pharmaceutical Preparations
Chemicals and Chemical Preparations, N.E.C
Glass Containers
Photographic Equipment and Supplies
Pesticides and Agricultural Chemicals, N.E.C.
Wood Household Furniture, Upholstered
Gaskets, Packing, and Sealing Devices
SIC
Code
2869
2833
9999
Unk.
2821
4953
2911
2865
2819
7389
2834
2899
3221
3861
2879
2512
3053
Hazard
Score
1.216+14
3.72e+13
1.05e+13
8.34e+12
5.45e+12
2.77C+12
1.83e+12
1.27e+12
8.00C+11
4.77e+ll
4.22C+11
2.10e+ll
l.lSe+ll
7.49e+10
5.11C+10
2.59e+10
Z28e+10
%of
Hazard
63.56
19.47
5.52
4.37
2.85
1.45
0.96
0.67
0.42
0.25
0.22
0.11
0.06
0.04
0.03
0.01
0.01
Cum % of
Hazard
63.56
83.03
88.55
92.92
95.77
97.22
98.18
98.85
99.27
99.52
99V74
99.85
99.91
99.95
99.97
99.99
100.00
3-21 .
-------
EXHIBIT 3-9
SOURCE CODES, RANKED BY HAZARD SCORES
Hazard
Rank
1
2
3
4
5
6
7
8
9
W
11
12
13
14
15
16
17
18
Source Code Description
Product distillation
Product filtering
Other
Unknown
Spent process liquids removal
Solvents recovery
Product rinsing
Other pollution control or waste treatment
By-product processing
Incineration/Thermal treatment
Wastewater treatment
Filtering/screening
Product solvent extraction
Oil changes
Other non-surface preparation processes
Routine cleanup wastes
Discontinue use of process equipment
Clean out process equipment
Source
Code
A33
A32
A99
Unk
A37
A73
A31
A89
A35
A74
A75
A71
A34
A54
A49
A92
A56
A09
Hazard
Score
1.18e+14
3.72e+13
1.07e-fl3
9.23e+12
5.90e+12
2.50e+12
2.22e+12
1.57e+12
1.48e+12
1.33e+12
5.42e+ll
2.59e+ll
1.72e+ll
l.lSe+11
7.49e+10
2.59e+10
2.28e+10
7.98e+08
%of
Hazard
61.58
19.47
5.62
4.84
3.09
1.31
1.16
0.82
0.78
0.70
0.28
0.14
0.09
0.06
0.04
0.01
0.01
0.00
Cum. % of
Hazard
61.58
81.05
86.66
91.50
94.59
95.90
97.07
97.89
98.66
9936
99.65
99.78
99.87
99.93
99.97
99.99
100.00
100.00
3-22
-------
EXHIBIT 3-10
GENERATION AND MANAGEMENT PATTERNS FOR THE
TOP TEN-RANKED WASTESTREAM COMBINATIONS
Wastestream
Combination Rank
No. of BRS Records of
Wastestreams.
No. of Facilities
Place of Management
Region
State
1
3
1
on
site
VI
TX
2
1
1
on
site
I
CT
3
1
1
on
site
III
PA
4
2
1
on
site
VI
TX
5
1
1
off
site
V
IN
6
2
1
on
site
VI
TX
7
12
12
off site
I,II,III
CT.MA,
NJ.NY,
PA.VA,
wv
8
1
1
on
site
IV
KY
9
1
1
on
site
III
VA
10
450
450
both
many
many
3-23
-------
EXHIBIT 3-11
TOP 100 COMBUSTED WASTESTREAM HAZARD SCORES BY REGION AND STATE
Region
I
2
3
4
5
6
7
State
CT
MA
NJ
NY
PA
VA
AL
FL
GA
KY
TN
IL
IN
Ml
OH
WI
AR
LA
TX
MO
Other States
Total:
Hazard Score
3.72e+13
2.046+11
3.30e+12
3.17e+ll
2.38e+13
2.006+12
3.27e+ll
4.446+11
4.666+11
S.Ole+12
6.756+11
2.676+11
1.076+13
1.15e+ 12
1.22e+12
2.05e+ll
6.05e+ll
2.94e+ 12
l.Ole+14
3.20e+ll
3.336+11
1.91e+14
%of 1
Total
1950
0.10
1.70
0.20
12.50
1.00
0.20
0.20
0.20
1.60
0.40
0.10
5.60
0.60
0.60
0.10
0.30
1.50
53.10
0.20
0.17
100.00
Note: @ - States with hazard score percentages less than 0.1 percent are not listed.
3-24
-------
focused on combusted hazardous wastes, could also potentially be applied to
wastes managed by other practices.
EPA recognizes that factors other than hazard may also be important in setting
priorities for waste minimization. Some examples include:
technical and economic feasibility of waste minimization alternatives
potential to build on other ongoing pollution prevention activities
waste treatment/management capacity
environmental justice concerns
- potential for wastes to cause difficult remediation problems (e.g., dense
non-aqueous phase liquids are particularly difficult to remediate when they
contaminate ground water).
EPA will continue refining the prioritization methodology'and investigating
alternative data sources based on comments received.
3.3 LIMITATIONS
Most of the limitations associated with the scoring and ranking methodology fall into one
of two categories: (1) limitations due to the uncertainty of the underlying waste characterization
data; or (2) limitations inherent to the scoring method. A key limitation in the first category is
briefly described below:
Hazard scores are subject to the uncertainty in the underlying waste
characterization/constituent concentration data. As discussed in Chapter 2, there is
significant uncertainty associated with the constituent content and concentrations
that were estimated for each wastestream combination. For example, due to the
nature of the data sources used, constituent content and concentration estimates
may not correspond completely to current waste characteristics, and may not
reflect the variability of waste characteristics over time and across generators.
Because the scoring methodology relies directly on the constituent content and
concentration, the hazard scores are limited by the same uncertainty that is
inherent in the underlying data.
Limitations in the second category include those that are common to most screening-level
scoring and ranking approaches, those that apply to the HRS, and those associated with using
components of the HRS for this specific application, i.e., ranking wastestream combinations.
Method incorporates assumptions and limitations of the HRS. Because it is a
screening-level scoring and ranking approach, the HRS incorporates certain
simplifying assumptions. For example, ecosystem hazard is evaluated using an
aquatic ecosystem model only; terrestrial ecosystems are not accounted for.
Furthermore, human toxicity is not differentiated by route of exposure. The effect
of these simplifying assumptions is thus indirectly conveyed to the wastestream
scores and ranks. (For more discussion of the assumptions and their rationale in
the HRS, see 55 Federal Register 51532.)
3-25
-------
Approach does not account for hazards related to corrosive and
ignitable/flamtnahle nature of some hazardous wastestreams. Some of the
hazardous wastestreams contain constituents that render the wastestreams
ignitable, corrosive, or reactive. The hazard scoring methodology does not factor
into the final scores, the types of acute hazards to humans or ecosystems that these
wastestreams may pose.
Method does not directly address releases and exposures, particularly post-
combustion releases and exposures. The scoring methodology accounts for
constituent properties that relate to the potential for exposure; however, the
methodology contains no mechanism to account for direct releases and exposures
(or system controls that prevent or reduce releases). Therefore, unique aspects of
Subtitle C waste management to which the wastestreams are subject (e.g.,
destruction and removal in combustion) and site-specific characteristics (size of
population that could potentially be exposed if releases occur) are not considered
in this screening-level scoring methodology.
Method does not correspond directly to a measure of "absolute" risk. The scoring
system is intended to provide an indication of the relative hazard of different
wastestreams. It does not, however, indicate whether the risks posed by
combustion of the wastes are in the range that EPA typically considers significant
As a practical matter, any method that seeks to simulate complex environmental processes,
but is founded on simple scoring algorithms and uncertain data, will always carry with it severe
limitations. Some of these limitations may become less constraining as the approach is refined
and improved. The Agency looks forward to receiving comments and data on the proposed
approach for setting priorities for waste minimization, and will carefully consider all information it
receives.
3-26
------- |