Documentation for RSEI Geographic
Microdata (RSEI-GM)

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RSEI Geographic Microdata Documentation

Contents

RSEI Geographic Microdata are summarized differently than the RSEI facility-level data	6

Microdata users should familiarize themselves with RSEI methods and data	8

Outliers should be checked	8

Adjustments must be made for time-series analysis	9

Air and water Microdata are distributed separately	10

Microdata file types	11

File Descriptions and Naming Conventions	13

Grid Cell Microdata files	13

Block Group Microdata files	14

Census Tract Microdata files	15

ZIP Code Microdata files	16

Water Microdata files	17

Census crosswalk files	18

Public Release Data files (data tables)	19

Grid Shapefiles	19

Linking RSEI tables	19

Appendix 1. Field Descriptions for Microdata Tables	23

Disaggregated Grid Cell Microdata	23

Aggregated Grid Cell Microdata	24

State Aggregated Grid Cell Microdata Shapefiles	24

Disaggregated Block Group Microdata	25

Block Group Shapefiles (dbf file)	26

Block Group Aggregated Data (csv file)	26

Disaggregated Census Tract Microdata	27

Census Tract Shapefiles (dbf file)	28

Census Tract Aggregated Data (csv file)	28

Disaggregated ZIP Code Microdata	29

ZIP Code Shapefiles (dbf file)	30

ZIP Code Aggregated Data (csv file)	30

Water Microdata: Annual Aggregated Shapefiles	31

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Water Microdata: All Years Discharges	31

Census Crosswalk Table	32

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Documentation for RSEI Geographic
Microdata (RSEI-GM)

The Risk-Screening Environmental Indicators (RSEI) Geographic Microdata (GM) (RSEI-GM)1 are
unique datasets that provide detailed air and water modeling results at various levels of
aggregation, spatial geographies, and time periods for data users. RSEI Geographic Microdata
allow for a flexible ability to analyze RSEI model outputs and results from a receptor-based
perspective of potentially impacted geographic areas. In contrast to the suite of RSEI results
that are distributed in tools such as EPA's EasyRSEI dashboard and in EPA's Envirofacts data
warehouse,2 RSEI Microdata are not aggregated and assigned to the facility level, but rather
include values resulting from where the chemical releases and potential impacts may occur.

RSEI Microdata are made available in a variety of data and file formats to meet analytical needs.
The most detailed files are disaggregated grid cell files, meaning values are presented for each
modeled chemical release and each impacted 810 meter by 810 meter grid cell. These
disaggregated files are very large in size (up to 120 gigabyte (GB) per year for the entire United
States) and can be difficult to download and manipulate from a technical perspective. To make
data analysis easier for users, EPA also produces Microdata files at less granular levels, including
census block groups, census tracts, and zone improvement plan (ZIP) codes, and produces
aggregated files that sum up RSEI results into single values for each geographic unit. In the RSEI
Microdata for air, the modeling results available include chemical concentrations, toxicity-
weighted concentrations, and RSEI Scores. In the RSEI Microdata for water, the modeling
results available include chemical concentrations and toxicity-weighted concentrations for each
stream segment or flowline downstream of a water discharge.

More information about downloading the RSEI Microdata can be found on the RSEI website.

Beginning with the 2018 Toxics Release Inventory (TRI) reporting year, RSEI Microdata
datasets are typically produced on a two-year alternating schedule. In even TRI reporting
years (2018,2020, etc.), expanded Microdata datasets are produced that include RSEI model
results for all TRI reporting years (1988-current) at different geographies (i.e., grid cell, block
group, census tract, and ZIP code) for different chemical sets (e.g., all chemicals, core
chemicals/original industries, 2001 core chemicals). In odd TRI reporting years (2019, 2021,
etc.), Microdata are only produced for the three most recent TRI reporting years. Non-routine
or ad hoc Microdata datasets may also be produced in odd years and will be made available
to the public.

1	The use of the word "Microdata" throughout this document should be interpreted to be synonymous and interchangeable
with the words "RSEI-GM" and "Geographic Microdata".

2	In order to make the RSEI data small enough to work with in a desktop database application, EasyRSEI adds up potential
impacts from certain waste management activities involving TRI chemicals and attributes them to the facilities of origin. These
facility-level results are also presented in Envirofacts.

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Each time a new RSEI version is released, the most recent three years of grid-cell level
Microdata will be available on the RSEI file transfer protocol (FTP) site, accessible through
ftp://newftp.epa.gov/RSEI/Current Version or https://gaftp.epa.gov/rsei/Current Version.
Previous versions will also be maintained on the ftp site.

Microdata files for different geographies, or for earlier years in the case of the even-year
expanded Microdata datasets, are available upon request; use the Contact Us form on the
RSEI website to send an email with your request.

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RSEI Geographic Microdata are summarized
differently than the RSEI facility-level data

RSEI facility-level results are distributed in a compact form in tools like EasyRSEI and in
applications like EPA's Envirofacts data warehouse. The RSEI facility-level data use the same
underlying modeling results as the Microdata, but then sum and assign RSEI result values
resulting from each modeled chemical waste management activity (e.g., releases to the
environment, transfers off site) back to the original waste-generating facility. For example,
when ranking counties or states in EasyRSEI, you are actually ranking the sum of facility-level
RSEI results resulting from all waste-originating facilities who are located in each county or
state. Being that the chemical release is the ultimate unit of analysis for the RSEI model,3
potential impacts resulting from chemical waste management activities may occur elsewhere in
another county or state. The RSEI facility-level results do not account for where these potential
impacts may be occurring geographically, but rather attribute the potential impacts to where
the chemical waste originated from.

To highlight this dichotomy, using Figure 1 below as a hypothetical example, a facility located in
the state of Delaware impacts air quality across the borders in the nearby states of
Pennsylvania and Maryland. In EasyRSEI and other applications that present RSEI facility-level
results, the RSEI pounds-based, hazard-based, and risk-related (score) result values associated
with this facility will all be attributed to the state of Delaware in a query that looked at RSEI
results by state. In a separate query that now looked at the RSEI Microdata (not the RSEI
facility-level results) by state, the RSEI-modeled result values resulting from this facility would
be split among the three states (Delaware, Pennsylvania, and Maryland) according to where the
potential impacts may ultimately be occurring.

3 More specifically, it is the chemical release pathway; for instance, water releases can be split into different pathways for fish
consumption and drinking water exposure. Chemicals in wastes may also be transferred off site for further waste management
(such as for disposal or further treatment) and may ultimately be released to the environment at the off-site location.

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Figure 1. Hypothetical scenario of an emissions plume crossing state boundaries (not to scale)

The RSEI facility-level and the RSEI Microdata datasets are both based on the same underlying
modeling, and as a result, total RSEI-modeled result values will be the same at the national-
scale level in either dataset. The facility-level dataset is appropriate for prioritizing chemicals,
facilities, industries, and pollution prevention opportunities or for screening for situations that
may warrant further investigation. Ranking or looking at trends for geographic areas can be
useful as long as users understand the nature of the RSEI facility-based data.

With the Microdata, geographic-based analyses are more intuitive; when you rank states, you
are ranking the potential impacts that may occur within the geographic confines of each state,
regardless of where the chemical releases or generated wastes originate. Impacts resulting
from on-site or off-site management of chemical waste are attributed to the geographic areas
located around the facilities that ultimately release the chemical into the environment. The
Microdata are provided for looking at small-scale geographic areas, and users can examine the
potential impacts that environmental releases of toxic chemicals from multiple facilities may
have on a particular area from a relative risk-related perspective.

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Microdata users should familiarize themselves

with RSEI methods and data

As with any screening-level model, RSEI is subject to the limitations, caveats, and assumptions
of the underlying data sources and models that it incorporates. You should carefully consider
and contextualize the strengths, weaknesses, and meaning that the RSEI methodology and
results may have on any analysis or investigation. RSEI relies primarily on TRI-reported data,
which only captures information regarding certain toxic chemical waste management activities
from facilities subject to TRI reporting requirements. RSEI does not provide information
regarding many other sources of environmental pollution or potential risk, including mobile
sources, small industrial or commercial facilities, and contaminated hazardous waste
(Superfund) sites. The RSEI website contains more description about RSEI, TRI, and other
important environmental data sources and useful resources in gathering more information.

Outliers should be checked

The accuracy and validity of TRI data submitted to EPA is entirely the responsibility of the
facilities that submit the data. Given the importance of the TRI to the public and other users of
the data, EPA is committed to helping facilities submit TRI data of optimal quality, and has
implemented activities to support this goal. The data in the TRI database are subject to ongoing
data quality review and corrective actions by both EPA and by TRI-reporting facilities. The RSEI
model uses the same TRI dataset used for EPA's annual TRI National Analysis, which represents
data contained in the TRI database at a given point in time in the autumn season following the
July TRI reporting deadline for toxic chemical release reporting forms. Data received by EPA too
late to be included in this dataset used for the TRI National Analysis and the RSEI model update
are made available to the public the following spring season (after the TRI database has been
updated and refreshed) through Envirofacts and other online tools and data sources made
available by EPA for accessing and analyzing TRI data. Depending on timing, these online tools
and data sources may contain more current TRI data that should be checked for any revisions to
anomalously high RSEI result values seen in RSEI data products.

In addition, some high toxicity-weighted concentrations in RSEI are driven by reporting of TRI
chemical categories, like certain glycol ethers or various metal compounds such as lead
compounds or nickel compounds. Because specific data on the exact identities of these
compounds are not reported to TRI, RSEI models a worst-case scenario and assumes that the
most toxic form of the chemical or chemical compound is being released for the majority of
scenarios. Exceptions to this include polycyclic aromatic compounds (PACs) and chromium and
chromium compounds, for which RSEI assumes a more likely release scenario and toxicity
profile based on EPA's National Emissions Inventory (NEI) data.4 In all of these cases, additional
investigation needs to be done to determine the exact identities and forms of the chemicals

4 The RSEI toxicity topic page provides more information. Also see https://www.epa.gov/air-emissions-inventories/national-
emissions-inventorv-nei to learn more about NEI data.

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being released to the environment before any conclusions about potential impacts or risks can
be drawn.

Adjustments must be made for time-series
analysis

When using the Microdata over more than one year, users should take care to ensure that the
same set of TRI reporting requirements are in force for the whole time period of the analysis.
The Chemical table (Chemical.csv, available in the Public Release Data tables or through the
RSEI data dictionary) has a series of fields (e.g., CoreOlChemicalFlag) to help with picking the
appropriate chemical set for a given time-series analysis; the year in the field name is the
beginning TRI reporting year for which reporting requirements have not changed over time. For
instance, the Core98ChemicalFlag field is "1" (or "True") for any TRI-Iisted chemical whose
reporting requirements have been constant over the TRI reporting years from 1998-present.
Users should limit their time series to those chemicals whose requirements have not changed
over the period of time being considered; otherwise differences in reporting may skew results
(e.g., increases in number of reportable chemicals may erroneously imply increases in potential
impacts). Microdata files for "Core" (1988-current) and "CoreOl" (2001-current) are produced
every other year in the extended Microdata set. The following table shows the core fields
available in the chemical table, along with the time period to which each flag pertains.

Core Flags Available in the Chemical Table*

Field Name

Time Period

Core88ChemicalFlag

1988-current

Core95ChemicalFlag

1995-current

Core98ChemicalFlag

1998-current

CoreOOChemicalFlag

2000-current

CoreOlChemicalFlag

2001-current

CorellChemicalFlag

2011-current

Corel2ChemicalFlag

2012-current

*The RSEI core chemical lists are defined by the lists found on the TRI
Explorer website here, under "Chemical".

Users should also be aware that the following seven industry groups were added to list of
facilities subject to the TRI reporting requirements for reporting year 1998:

•	Metal mining

•	Coal mining

•	Electric utilities

•	Commercial hazardous waste treatment

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•	Chemicals and allied products-wholesale

•	Petroleum bulk terminals and plants-wholesale

•	Solvent recovery services

If a time-series analysis includes 1998, those seven industry groups are recommended to be
removed prior to analysis. The RSEI Facility table (Facility.csv) also has a True/False field called
NewlndustryFlag that is "1" (or "True") for facilities in the seven industry groups added for
reporting year 1998. More information on the TRI industry expansion.

The TRI Program's Factors to Consider When Using Toxics Release Inventory Data contains
additional important information to consider when accessing and analyzing TRI data over the
years.

Air and water Microdata are distributed
separately

RSEI water Microdata are produced with different spatial geography than the RSEI air
Microdata. Instead of the RSEI grid cell that is used in the air Microdata, the water Microdata
use the flowline, or stream segment, as the basic unit of analysis. Before using the water
Microdata, users should familiarize themselves with the RSEI water modeling methodology and
be aware that TRI data do not include all toxic chemical discharges to water (see the RSEI
website for more information on the TRI reporting universe and where to find other sources of
environmental release data). The RSEI modeled concentrations for each flowline reflect annual
chemical water releases discharged upstream, assumed to be released to surface waters at a
constant rate over the year, and do not generally reflect the current state of impairment of the
receiving stream or water body.

The RSEI water Microdata is indexed by flowline Common ID (COMID), which is a unique
identifier assigned by the NHDPIus data set. Version 2. NHDPIus is based on the U.S. Geological
Survey (USGS)'s medium resolution National Hydrography Dataset (NHD), and adds important
information like stream flow and velocity estimates that are necessary for water modeling.

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Microdata file types

There are different kinds of files that contain Microdata results, and over time additional files
will likely be produced to help users get the information they need in the easiest way possible.

Universes. There are three possible universes of chemicals and facilities provided:

•	Core- limited to the set of TRI-listed toxic chemicals whose reporting requirements have
not changed over the entire TRI reporting time period and to the set of original
industries subject to TRI reporting requirements.5 This is the smallest universe of
chemicals and facilities.

•	CoreOl- limited to the set of TRI-listed toxic chemicals whose reporting requirements
have not changed since TRI reporting year 2001. Includes all reporting facilities.

•	All chemicals- includes all TRI-listed toxic chemicals reported to TRI and all reporting
facilities. Any Microdata file with no core specification in the file name contains all TRI-
listed chemicals and reporting facilities.

EPA's TRI program maintains a list of regulatory activities with respect to changes in TRI
chemical and facility reporting requirements, which can be found through the TRI website here:
https://www.epa.gov/toxics-release-inventorv-tri-program/tri-laws-and-regulatory-activities
Also, in the RSEI data dictionary tables, the Chemical table has a field FirstReportingYear which
indicates the first TRI reporting year for a given chemical (not the calendar year in which the
given chemical was added to the TRI list), and fields like CoreOlChemicalFlag which is "1" or
"True" if that chemical is on that particular core chemical list. Using these flags, users can
extract any other core chemical subset from the set of all TRI-listed chemicals.

Aggregations. The Microdata can be presented at two different levels:

•	Disaggregated. This is the most detailed and granular level of data available, where each
chemical release and corresponding RSEI result values are presented separately, so that
users can see what chemicals and facilities are affecting geographic spatial units (grid
cell, census tract, etc.).

•	Aggregated. In aggregated files, chemical releases and corresponding RSEI result values
(e.g., toxicity-weighted concentrations and risk-related (score) results) are summed
together for each geographic spatial unit.6

Geography. Microdata are created for the following geographic spatial units:

Air Microdata

•	Grid cell. The 810 meter by 810 meter basic unit of the RSEI grid cell system, defined by
an x,y address. Section 5.1 of the RSEI methodology document contains more detailed
information on the technical specifications for the RSEI grid, as well as equations for
translating latitude and longitude coordinates into a locational (x,y) address. RSEI grid

5	Facilities in North American Industry Classification System (NAICS) codes that correspond to the seven industry groups added
in TRI reporting year 1998 are not included.

6	Chemical concentrations are not summed in the aggregated Microdata files, therefore RSEI-modeled chemical concentrations
are not available at this level of aggregation.

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shapefiles that define the grid are available for download on the RSEI FTP site for use in
mapping.

•	Block group. The 2010 U.S. census boundaries are used.

•	Census tract. The 2010 U.S. census boundaries are used.

•	ZIP code. 2017 ZIP code boundaries are used.

Water Microdata

•	Flowline. Stream segments as defined in the NHDPIus Version 2 dataset. Each flowline is
indexed by a unique identifier called "COMID".

Coverage.

•	Grids. The aggregated grid cell Microdata is split into separate grids. One file contains
only the conterminous U.S.; other files contain Alaska, Hawaii and island areas. Only grid
cells with non-zero concentrations are included; if a grid cell is not affected by any
releases, it will not be in the file. The grid codes are as follows:

o 14 = Conterminous US
o 24 = Alaska
o 34 = Hawaii

o 44 = Puerto Rico/Virgin Islands
o 54 = Guam/Marianas Islands
o 64 = American Samoa

•	National. Most files are for the entire U.S., including island areas. As with the
aggregated grid cell files, if a geographic unit is not affected by any releases, it will not
be included in the file.

•	State. State-level shapefiles are provided that include all RSEI grid cells that define the
state, regardless of RSEI modeled concentrations. Users can use the state-level
shapefile as a template set of x,y addresses to then extract state-specific Microdata
results from other grid cell level files (e.g., for other TRI reporting years).

File Type. There are two basic kinds of file types produced:

•	Comma-delimited text file. See field descriptions in Appendix 1 at the end of this
document for more specifics.

•	Shapefiles. Each zip file contains a comma-delimited text file as well as the set of files
that define the shapefile. Note that some of these files are very large and may not be
viewable in some entry-level geographic information system (GIS) software programs.

The files are generally zipped in gzip (file extension ".gz"), or Winzip (file extension ".zip")
formats, both of which can be unzipped using Windows Explorer or a command line. The
following sections describe each type of Microdata file and how they are named. Field names
and descriptions for each type of file can be found in Appendix 1.

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File Descriptions and Naming Conventions

Grid Cell Microdata files

Disaggregated Microdata files
Approximate Size: 110 GB, 25 GB when zipped

Description: These are the Microdata files that contain the most disaggregated data possible.
For each 810m by 810m grid cell, the file includes RSEI result values such as risk-related results
(scores), concentrations, and toxicity-weighted concentrations for each modeled chemical
release. There may be multiple records for any one particular grid cell. As an example, if two
releases of the same chemical impact the same grid cell, there will be separate records for each
release.7

Naming: These annual files are named as microXXXX_YYYY, where XXXX is the TRI reporting
year (RY) data freeze used for the RSEI model, and YYYY is the TRI reporting year data contained
in the file. For example, micro2014_2010 is from the TRI RY 2014 RSEI update, and contains
data for chemicals released in 2010.

See the Disaggregated Grid Cell Microdata table in Appendix 1 for field names and descriptions.
Aggregated Microdata files

Approximate Size: 700 MB, 200 MB when zipped (for GC 14, the conterminous U.S.)
Description: Aggregated Microdata files use the same data as the disaggregated files, but sum
the RSEI result values over all the chemical releases affecting each grid cell. Because the values
are summed, unweighted concentrations are not available.

Naming: These annual files are named aggmicroXXXX_YYYY_gcZZ, where XXXX is the TRI
reporting year (RY) data freeze used for the RSEI model, YYYY is the TRI reporting year data
contained in the file, and ZZ is the grid code. For example, aggmicro2017_2010_gcl4 is from
the TRI RY 2017 RSEI update, contains data for chemicals released in 2010, for grid code 14 (the
conterminous United States).

See the Aggregated Grid Cell Microdata table in Appendix 1 for field names and descriptions.
State Shapefiles

Approximate Size: less than 100 MB when all files zipped

Description: These zip files contain shapefiles with aggregated grid cell-level data for individual
states for the most recent data year only. The data are presented in a shapefile format for use
with GIS programs. Due to the size of the national-scale grid cell Microdata files, a set of state-
specific files are made available. For this set only, RSEI grid cells with no impacts are included; in
this way, each state file includes every grid cell within the state, and it can be merged with the

7 Note that this may either occur from releases from different facilities or from multiple types of releases (e.g., stack air
emissions, fugitive air emissions) from the same facility.

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national-scale files to extract data for one state from other grid cell-level files. For state
shapefiles, a comma-delimited text file is not included.

Naming: These files are named ss_aggmicroYYYY.zip, where ss is the 2-letter state abbreviation
and YYYY is the TRI reporting year (RY) data freeze used for the RSEI model and also the TRI RY
data contained in the file. The state-level shapefiles are only produced for the most recent TRI
reporting year for each expanded Microdata datasets.

See the State Aggregated Grid Cell Microdata Shapefiles table in Appendix 1 for field names and
descriptions.

Block Group Microdata files

Disaggregated Block Group Microdata
Approximate Size: 15 GB, 3 GB when zipped

Description: These files are the same as the grid cell disaggregated Microdata files, but instead
of being presented at the grid cell level, the values are averaged and presented for census block
groups. For each census-defined block group, the file includes RSEI result values such as risk-
related results (scores), concentrations, and toxicity-weighted concentrations for each modeled
chemical release. There may be multiple records for any one block group; for instance, if two
releases for the same chemical (either from different facilities or one from a stack release and
one from a fugitive release from the same facility) affect the same block group, there will be
separate records for each release.

Naming: These annual files are named as censusmicroblockgroupXXXX_YYYY, where XXXX is
the TRI reporting year (RY) data freeze used for the RSEI model, and YYYY is the TRI reporting
year data contained in the file. For example, censusmicroblockgroup2017_2010 is from the TRI
RY 2017 RSEI update, and contains data for chemicals released in 2010.

See the Disaggregated Block Group Microdata table in Appendix 1 for field names and
descriptions.

Block Group Shapefiles

Approximate Size: less than 1 GB when all files zipped

Description: These zip files contain the same data as the disaggregated block group files, but
sum the chemical releases and corresponding RSEI result values over each block group, so that
there is only one record in each table for each affected block group. The data are presented in a
shapefile format for use with GIS programs. For user convenience, a standard database file
(dbf) and a comma-delimited text file (provided as a comma-separated values (csv) file) are
included in each zip file; that text file is the same as the text file for the aggregated Microdata.
These files do not contain chemical- or facility-specific information, except the number of
facilities and chemicals affecting each block group. These files also contain percentile fields to
help in mapping.

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Naming: These annual files are named as censusmicroblockgroupXXXX_YYYY_aggregated,
where XXXX is the TRI reporting year (RY) data freeze used for the RSEI model, and YYYY is the
TRI reporting year data contained in the file. For example,

censusmicroblockgroup2017_2010_aggregated is from the TRI RY 2017 RSEI update, and
contains data for chemicals released in 2010.

See the Block Group Shapefiles (dbf file) table in Appendix 1 for field names and descriptions.

Aggregated Block Group Microdata
Approximate Size: 20 MB, 7 MB when zipped

See block group shapefiles description above; the aggregated block group data are available in
the zip shapefile or as a separate comma-delimited csv text file. The fields differ slightly
between the dbf and csv files.

See the Block Group Aggregated Data (csv file) table in Appendix 1 for field names and
descriptions.

Census Tract Microdata files

Disaggregated Census Tract Microdata
Approximate Size: 5 GB, 1 GB when zipped

Description: These files are the same as the grid cell disaggregated Microdata files, but instead
of being presented at the grid cell level, the values are averaged and presented over census
tracts. For each census-defined tract, the file includes RSEI result values such as risk-related
results (scores), concentrations, and toxicity-weighted concentrations for each modeled
chemical release. There may be multiple records for any one census tract; for instance, if two
releases for the same chemical (either from different facilities or one from a stack release and
one from a fugitive release from the same facility) affect the same census tract, there will be
separate records for each release.

Naming: These annual files are named as censusmicrotractsXXXX_YYYY, where XXXX is the TRI
reporting year (RY) data freeze used for the RSEI model, and YYYY is the TRI reporting year data
contained in the file. For example, censusmicrotracts2017_2010 is from the TRI RY 2017 RSEI
update, and contains data for chemicals released in 2010.

See the Disaggregated Census Tract Microdata table in Appendix 1 for field names and
descriptions.

Census Tract Shapefiles

Approximate Size: less than 500MB when all files zipped

Description: These zip files contain the same data as the disaggregated census tract files, but
sum the chemical releases and corresponding RSEI result values over each census tract, so that
there is only one record in each file for each affected census tract. The data are presented in a
shapefile format for use with GIS programs. For user convenience, a standard database file

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(dbf) and a comma-delimited text file (provided as a comma-separated values (csv) file) are
included in each zip file; that text file is the same as the text file for the aggregated Microdata.
These files do not contain chemical- or facility-specific information, except the number of
facilities and chemicals affecting each census tract. These files also contain percentile fields to
help in mapping.

Naming: These annual files are named as censusmicrotractsXXXX_YYYY_aggregated, where
XXXX is the TRI reporting year (RY) data freeze used for the RSEI model, and YYYY is the TRI
reporting year data contained in the file. For example,

censusmicrotracts2017_2010_aggregated is from the TRI RY 2017 RSEI update, and contains
data for chemicals released in 2010.

See the Census Tract Shapefiles (dbf file) table in Appendix 1 for field names and descriptions.

Aggregated Census Tract Microdata
Approximate Size: 6 MB, 3 MB when zipped

See census tract shapefiles description above; the aggregated census tract data are available in
the zip shapefile or as a separate comma-delimited csv text file. The fields differ slightly
between the dbf and csv files.

See the Census Tract Aggregated Data (csv file) table in Appendix 1 for field names and
descriptions.

ZIP Code Microdata files

Disaggregated ZIP Code Microdata
Approximate Size: 1.2 GB, 200 MB when zipped

Description: These files are the same as the grid cell disaggregated Microdata files, but instead
of being presented at the grid cell level, the values are averaged and presented over ZIP codes.
For each ZIP code, the file includes RSEI result values such as risk-related results (scores),
concentrations, and toxicity-weighted concentrations for each modeled chemical release. There
may be multiple records for any one ZIP code; for instance, if two releases for the same
chemical (either from different facilities or one from a stack release and one from a fugitive
release from the same facility) affect the same ZIP code, there will be separate records for each
release.

Naming: These annual files are named as censusmicrozipcodeXXXX_YYYY, where XXXX is the TRI
reporting year (RY) data freeze used for the RSEI model, and YYYY is the TRI reporting year data
contained in the file. For example, censusmicrozipcode2017_2010 is from the TRI RY 2017 RSEI
update, and contains data for chemicals released in 2010.

See the Disaggregated ZIP Code Microdata table in Appendix 1 for field names and descriptions.

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ZIP Code Shapefiles

Approximate Size: less than 500MB when all files zipped

Description: These zip files contain the same data as the disaggregated ZIP code files, but sum
the chemical releases and corresponding RSEI result values over each ZIP code, so that there is
only one set of records for each affected ZIP code. The data are presented in a shapefile format
for use with GIS programs. For user convenience, a standard database file (dbf) and a comma-
delimited text file (provided as a comma-separated values (csv) file) are included in each zip file;
that text file is the same as the text file for the aggregated Microdata. These files do not contain
chemical- or facility-specific information, except the number of facilities and chemicals affecting
each ZIP code. These files also contain percentile fields to help in mapping.

Naming: These annual files are named as censusmicrozipcodeXXXX_YYYY_aggregated, where
XXXX is the TRI reporting year (RY) data freeze used for the RSEI model, and YYYY is the TRI
reporting year data contained in the file. For example,

censusmicrozipcode2017_2010_aggregated is from the TRI RY 2017 RSEI update, and contains
data for chemicals released in 2010.

See the ZIP Code Shapefiles (dbf file) table in Appendix 1 for field names and descriptions.

Aggregated ZIP Code Microdata
Approximate Size: 2 MB, 1 MB when zipped

See ZIP code shapefiles description above, the aggregated ZIP code data are available in the zip
shapefile or as a separate comma-delimited csv text file. The fields differ slightly between the
dbf and csv files.

See the ZIP Code Aggregated Data (csv file) table in Appendix 1 for field names and
descriptions.

Water Microdata files

Water Microdata files come in two basic forms: yearly shapefiles containing toxicity-weighted
concentrations for each affected flowline, and all-years discharge-based files which contain
modeled concentrations for individual discharges at each downstream flowline. In both cases,
on-site discharges from TRI reporters are distributed separately from discharges from publicly-
owned treatment works (POTWs) resulting from off-site transfers from TRI reporters.

Annual Aggregated Shapefiles for Water Microdata
Approximate Size: 40 MB, 25 MB when zipped

Description: For these files, the individual toxicity-weighted concentrations from each
discharge are summed for each flowline. The data are presented in a shapefile format for use
with GIS programs. For user convenience, a standard database file (dbf) and a comma-delimited
text file (provided as a comma-separated values (csv) file) with toxicity-weighted
concentrations are included in each zip file; note that the text file has additional fields with
coordinates for three points on each flowline. These files do not contain chemical- or facility-

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specific information. The data are indexed by the flowline identifier (COMID), and the reach
code associated with each flowline is also provided.

Naming: These annual files are named as NHDMicroResults_Zsite_YYYY, where Z is "On" or
"Off" depending on whether the file contains results for on-site discharges or from discharges
resulting from off-site transfers to POTWs, and YYYY is the TRI reporting year data contained in
the file. For example, NHDMicroResults_Onsite_2015 is for on-site discharges, and contains
data for chemicals released in 2015.

See the Water Microdata: Annual Aggregated Shapefiles table in Appendix 1 for field names
and descriptions.

All Years Discharges for Water Microdata
Approximate Size: 5 GB, 1 GB when zipped

Description: These text files contain data for individual discharges, including concentration,
toxicity-weighted concentrations, downstream travel time, and year of release. Each record is
for a single discharge (defined by the ReleaseNumber) and single downstream flowline (defined
by the COMID). The reach code is also provided. Information on the discharging facility and the
chemicals discharged can be found by linking the ReleaseNumber contained in this file to the
Public Release Data files. See the section on linking RSEI tables for details.

Naming: These files are named as NHDMicroResults_conc_aggZsite, where Z is "On" or "Off"
depending on whether the file contains results for on-site discharges or from discharges
resulting from off-site transfers to POTWs. For example, NHDMicroResults_conc_aggOffsite is
for off-site discharges, and contains data for chemicals released in all years (1988-current).

See the Water Microdata: All Years Discharges table in Appendix 1 for field names and
descriptions.

Census crosswalk files

Each set of census crosswalk files links the RSEI grid cell geography to a different U.S. decennial
census year. There is one crosswalk for each area and decennial census year (i.e., 1990, 2000,
2010). Crosswalk files are named by area (Alaska, Con(terminous) U.S., etc.). The last three
fields in each crosswalk file contain percent values that can be used to adjust the census block
or grid cell contents when performing the crosswalk. The percent of the census block that is
within the grid cell (PCT_B_C) and the percent of the grid cell that is within the census block
(PCT_C_B) are area-weighted and can be used for metrics that do not involve population, such
as concentration and toxicity-weighted concentration. The percent of the grid cell's population
that is within the census block (PCT_PC_B) is population-weighted, and can be used to
crosswalk fields that involve population, such as risk-related (score) results. Note that the
"PCT_PC_B" field is not available for the territories (VI, PR, GU, AS, MP). The Northern Mariana
Islands are in the Guam file and the Virgin Islands are in the Puerto Rico file. There are no
crosswalks for Puerto Rico, the Virgin Islands, Mariana Islands, Guam, or American Samoa for

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1990. For these areas, the RSEI model uses 2000 census block boundaries and scales each grid
cell's population by the overall ratio of 1990/2000 population for each area.

If census geographies larger than block level are desired, users are advised to use the RSEI
Microdata geography files which are already crosswalked from grid cells to census block groups,
census tracts, and ZIP codes.

See the Census Crosswalk table in Appendix 1 for field names and descriptions.

Public Release Data files (data tables)

These data tables contain TRI reporting data and other data used in RSEI modeling, including
input parameters such as facility information and chemical toxicity. Figure 2 below shows the
relationships between the main Public Release Data tables. The RSEI Data Dictionary provides
field descriptions and data tables that are made available in comma-separated values (csv) and
spreadsheet (xlsx) formats for the most recent RSEI model version. The Public Release Data files
for current and older RSEI model versions can be found through the RSEI FTP site.

Grid Shapefiles

RSEI grid shapefiles define the RSEI grid and can be used for mapping purposes. These files do
not contain any RSEI modeled results. New grid shapefiles were posted on the RSEI FTP site in
early 2017. The shapes are the same as previous to 2017; however, the fields and format are
different, and now additional files for grid cell sizes other than 810 meter x 810 meter are
available. Shapefiles of the RSEI grid geography are available by grid region, in two versions:
polygon and center point. The RSEI Data Dictionary provides additional descriptions and
attribute data for the grid shapefiles.

Linking RSEI tables

The Microdata tables must be used with the RSEI Public Release Data files (data tables) of the
same RSEI model version.

Disaggregated Microdata data files provide information on each modeled chemical release
affecting each spatial geography.8 To save space, the facility, chemical, media, and release
details are stored in the RSEI Public Release Data tables. Each Public Release Data table links
into the Microdata tables using a key field (such as ChemicalNumber, FacilityNumber, etc.), as
illustrated in Figure 2, below. Field descriptions for these tables can be found in the RSEI Data
Dictionary. As an example, if a record in the disaggregated grid cell Microdata had a very high
toxicity-weighted concentration, you could find its ChemicalNumber (Field Number 5 in the
Disaggregated Grid Cell Microdata table in Appendix 1) and look it up in the Chemical table and

8 Aggregated Microdata data files combine release information and RSEI modeled results for each spatial geography, and thus
cannot be linked back to the RSEI data tables.

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find its chemical name, toxicity information, and when it was added to the TRI list of toxic
chemicals. Similarly, you could look up the FacilityNumber in the Facility table, and find the
facility name, location, and facility modeling parameters.

The air Microdata contains both on-site and off-site releases in the same file. If you are
interested in facility information for a given record in a disaggregated Microdata file, the
FacilityNumber links to the RSEI Facility table if the release is an on-site release from a TRI-
reporting facility (the value in the Media field will be 1 or 2); if the release is from an off-site
facility, the value in the Media field will be 6, 750, or 754 and the FacilityNumber in the
Microdata file links to the Off-site table. If you want information on the originating facility for
an off-site transfer (the TRI reporting facility that transferred the waste to, for instance, an off-
site incineration facility), use the ReleaseNumber in the Microdata file to link to the Releases
table. The FacilityNumber for the record in the Releases table links to the Facility table.9

It is very important to use the Public Release Data tables for the same RSEI model version as the
Microdata tables. For instance, you must use the RSEI model version V2.3.10 (TRI reporting year
2020) Public Release Data tables with the RSEI model version V2.3.10 (TRI reporting year 2020)
Microdata. The key field values change with each RSEI model version and update, so if you use
a different RSEI model version's tables to do analysis with the Microdata, you will get erroneous
results.

9 Each record in the Releases table includes the reporting facility (FacilityNumber) and the off-site facility, if applicable
(OffsiteNumber). The OffsiteNumber field in the Releases table is the same as the FacilityNumber field in the Offsite table.

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\

Submission

'ff DCN

SubmissionNurnbe

FacilityNumber

ChernicalNumber

SubmissionYear

Use

LongOrShort

MaxOnsite

TotalPounds

Facility

FacilitylD
$ FacilityNumber
Latitude
Longitude
GridCode
X
V

RadialDistance
StackHeight
StackVelocity
StackDiameter

Release

ReleaseNumber

SubmissionNumber

Media

PoundsReleased
OffsiteNumber
TotalScore
TEF

DateUpdated

Chemical

CASNumber j
CAS Standard
$ ChemicalNumb* -
Category
SortCAS
SortName
FullChemicalWa
Chemical
Added

ToxicitySource

RfCInhale

RfCUF

RfCMF

RfCConf

RfCSource

Elements

$ ElementNumbei

jk.



ReleaseNumber





PoundsPT





ScoreCategory

=



Score





Population





Score A





PopA





ScoreB





PopB





ScoreC
rv^r

~



Off site

OffsitelD

a.

$ FacilityNumber



NewNumber

m

POTW Incin



DataSource



Name



Street



City



State



ZIPCode



ZIP9



Latitude

~

Figure 2. Example relationships between RSEI Public Release Data tables

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RSEI Geographic Microdata Documentation

Recent RSEI model version numbers and TRI reporting year (RY) data freeze used for that RSEI
model update:

•	V2.3.1- RY 2010

•	V2.3.2- RY 2011

•	V2.3.3- RY 2012

•	V2.3.4- RY 2014

•	V2.3.5- RY 2015

•	V2.3.6- RY 2016

•	V2.3.7- RY 2017

•	V2.3.8- RY 2018

•	V2.3.9- RY 2019

•	V2.3.10- RY 2020

•	V2.3.11-RY 2021

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Appendix 1. Field Descriptions for
Microdata Tables	

These Microdata tables, along with the tables for the RSEI facility-level data, can also be found
in the RSEI Data Dictionary.

Disaggregated Grid Cell Microdata

Field Number Name

Description

1 GridCode

Identifies grid.
14=Conterminous US
24=Alaska
34=Hawaii

44=Puerto Rico/Virgin Islands
54=Guam/Marianas
64=American Samoa

2 X

X-coordinate of grid cell.

3 Y

Y-coordinate of grid cell.

4 ReleaseNumber

Internal unique identifier for release
(lookup in Releases table)1.

5 ChemicalNumber

Internal unique identifier of released chemical
(lookup in Chemical table)1.

6 FacilityNumber

Internal unique identifier of releasing facility
(If media = 1 or 2, then lookup in Facility table;
If media = 6 or 750 or 754, then lookup in Off-site
table)1.

7 Media

Code describing media into which chemical is
released.

(lookup in Media table)1.

8 Cone

Concentration of chemical for release/media at
grid cell (ng/m3).

9 ToxConc

Concentration multiplied by inhalation toxicity
weight.

10 Score

Risk-related score (estimated dose * toxicity
weight * potentially exposed population).

11 ScoreCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for cancer effects.

12 ScoreNonCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for noncancer effects.

13 Pop

Number of people in grid cell (may be
interpolated).

1 Other tables can be found in the Public Release Data tables, on the RSEI FTP site (ftp://newftp.epa.gov/RSEI/) or

https://saftp.epa.sov/RSEI, or in the RSEI data dictionary (https://www.epa.sov/rsei/rsei-data-dictionarv). Be sure to use the

data tables from the same RSEI model version as the Microdata.

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Aggregated Grid Cell Microdata

Field Number

Name

Description

1

X

X-coordinate of grid cell.

2

Y

Y-coordinate of grid cell.

3

NumberOf Facilities

Number of facilities with releases affecting grid
cell.

4

NumberOf Releases

Number of individual releases affecting grid cell.

5

NumberOfChemicals

Number of chemicals with nonzero concentrations
for grid cell.

6

ToxConc

Concentration multiplied by inhalation toxicity
weight, summed over all chemicals impacting grid
cell.

7

Score

Risk-related score (estimated dose * toxicity
weight * potentially exposed population), summed
over all chemicals impacting grid cell.

8

Pop

Population of grid cell.

9

ScoreCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for cancer effects.

10

ScoreNonCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for noncancer effects.

State Aggregated Grid Cell Microdata Shapefiles

Field Number

Name

Description

1

CELLX

X-coordinate of grid cell.

2

CELLY

Y-coordinate of grid cell.

3

CLAT

Latitude in decimal degrees of center of grid cell.

4

CLONG

Longitude in decimal degrees of center of grid cell.

5

PRIFIPS

5-digit FIPS code associated with the county in
which the largest percentage of the grid cell is
found.

6

NUMFACS

Number of facilities with releases affecting grid
cell.

7

NUMRELEASES

Number of individual releases affecting grid cell.

8

NUMCHEMS

Number of chemicals with nonzero concentrations
for grid cell.

9

TOXCONC

Concentration multiplied by inhalation toxicity
weight, summed over all chemicals impacting grid
cell.

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Field Number Name

Description

10 SCORE

Risk-related score (estimated dose * toxicity
weight * potentially exposed population), summed
over all chemicals impacting grid cell.

11 EXPOP

Population of grid cell, for cells with nonzero
concentrations only.

12 CSCORE

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for cancer effects.

13 NCSCORE

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for noncancer effects.

Disaggregated Block Group Microdata

Field Number Name

Description

1 GEOID

US Census Block Group ID

2 ReleaseNumber

Internal unique identifier for release
(lookup in Releases table)1.

3 ChemicalNumber

Internal unique identifier of released chemical
(lookup in Chemical table)1.

4 FacilityNumber

Internal unique identifier of releasing facility
(If media = 1 or 2, then lookup in Facility table;
If media = 6 or 750 or 754, then lookup in Off-site
table)1.

5 Media

Code describing media into which chemical is
released.

(lookup in Media table)1.

6 Cone

Concentration of chemical for release/media at
block group (ng/m3).

7 ToxConc

Concentration multiplied by inhalation toxicity
weight.

8 Score

Risk-related score (estimated dose * toxicity
weight * potentially exposed population).

9 ScoreCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for cancer effects.

10 ScoreNonCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for noncancer effects.

11 Pop

Number of people in block group (may be
interpolated).

1 Other tables can be found in the Public Release Data tables, on the RSEI FTP site (ftD://newftD.eDa.eov/RSEI/) or
httDs://eaftD.eDa.eov/RSEI. or in the RSEI data dictionary (httDs://www.eDa.eov/rsei/rsei-data-dictionarv). Be sure to use the

data tables from the same RSEI model version as the Microdata.

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Block Group Shapefiles (dbf file)

Field
Number

Name

Description

1

GEOID

US Census Block Group ID.

2

NUMFACS

Number of facilities affecting the block group.

3

P NUMFACS

Percentile associated with field NUMFACS.

4

NUMRELEASES

Number of releases affecting the block group.

5

P NUMRELEASES

Percentile associated with field NUMRELEASES.

6

NUMCHEMS

Number of chemicals affecting the block group.

7

P NUMCHEMS

Percentile associated with field NUMCHEM.

8

TOXCONC

Average toxicity-weighted concentration of the cells in the
block group.

9

P TOXCONC

Percentile associated with field TOXCONC.

10

SCORE

Sum of the risk-related scores (estimated dose * toxicity
weight * potentially exposed population) of the cells in the
block group.

11

P SCORE

Percentile associated with field SCORE.

16

POP

Sum of the population of the cells in the block group.

17

P POP

Percentile associated with field POP.

14

CSCORE

Sum of the risk-related scores (estimated dose * toxicity
weight * potentially exposed population) of the cells in the
block group. Score is calculated using only cancer toxicity
weights.

15

P CSCORE

Percentile associated with field CSCORE.

12

NCSCORE

Sum of the risk-related scores (estimated dose * toxicity
weight * potentially exposed population) of the cells in the
block group. Score is calculated using only noncancer
toxicity weights.

13

P_NCSCORE

Percentile associated with field NCSCORE.

Block Group Aggregated Data (csv file)

Field Number

Name

Description

1

GEOIDIO

US Census Block Group ID.

2

NUMFACS

Number of facilities affecting the block group.

3

NUMRELEASES

Number of releases affecting the block group.

4

NUMCHEMS

Number of chemicals affecting the block group.

5

TOXCONC

Average toxicity-weighted concentration of the
cells in the block group.

6

SCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the block group.

7

POP

Sum of the population of the cells in the block
group.

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Field Number Name

Description

8 CSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the block group. Score is calculated
using only cancer toxicity weights.

9 NCSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the block group. Score is calculated
using only noncancer toxicity weights.

Disaggregated Census Tract Microdata

Field Number Name

Description

1 GEOID

US Census Tract ID.

2 ReleaseNumber

Internal unique identifier for release
(lookup in Releases table)1.

3 ChemicalNumber

Internal unique identifier of released chemical
(lookup in Chemical table)1.

4 FacilityNumber

Internal unique identifier of releasing facility
(If media = 1 or 2, then lookup in Facility table;
If media = 6 or 750 or 754, then lookup in Off-site
table)1.

5 Media

Code describing media into which chemical is
released.

(lookup in Media table)1.

6 Cone

Concentration of chemical for release/media at
census tract (ng/m3).

7 ToxConc

Concentration multiplied by inhalation toxicity
weight.

8 Score

Risk-related score (estimated dose * toxicity
weight * potentially exposed population).

9 ScoreCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for cancer effects.

10 ScoreNonCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for noncancer effects.

11 Pop

Number of people in tract (may be interpolated).

1 Other tables can be found in the Public Release Data tables, on the RSEI FTP site (ftp://newftp.epa.gov/RSEI/) or
https://eaftR.epa.eov/RSEI. or in the RSEI data dictionary (https://www.epa.eov/rsei/rsei-data-dictionarv). Be sure to use the

data tables from the same RSEI model version as the Microdata.

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Census Tract Shapefiles (dbf file)

Field Number

Name

Description

1

GEOID

US Census Tract ID.

2

NUMFACS

Number of facilities affecting the tract.

3

P_NUMFACS

Percentile associated with field NUMFACS.

4

NUMRELEASES

Number of releases affecting the tract.

5

P_NUMRELEASES

Percentile associated with field NUMRELEASES.

6

NUMCHEMS

Number of chemicals affecting the tract.

7

P_NUMCHEMS

Percentile associated with field NUMCHEM.

8

TOXCONC

Average toxicity-weighted concentration of the
cells in the tract.

9

P_TOXCONC

Percentile associated with field TOXCONC.

10

SCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the tract.

11

P_SCORE

Percentile associated with field SCORE.

16

POP

Sum of the population of the cells in the tract.

17

P POP

Percentile associated with field POP.

14

CSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the tract. Score is calculated using only
cancer toxicity weights.

15

P_CSCORE

Percentile associated with field CSCORE.

12

NCSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the tract. Score is calculated using only
noncancer toxicity weights.

13

P_NCSCORE

Percentile associated with field NCSCORE.

Census Tract Aggregated Data (csv file)

Field Number

Name

Description

1

GEOIDIO

US Census Tract ID.

2

NUMFACS

Number of facilities affecting the tract.

3

NUMRELEASES

Number of releases affecting the tract.

4

NUMCHEMS

Number of chemicals affecting the tract.

5

TOXCONC

Average toxicity-weighted concentration of the
cells in the tract.

6

SCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the tract.

7

POP

Sum of the population of the cells in the tract.

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Field Number Name

Description

8 CSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the tract. Score is calculated using only
cancer toxicity weights.

9 NCSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the tract. Score is calculated using only
noncancer toxicity weights.

Disaggregated ZIP Code Microdata

Field Number Name

Description

1 GEOID

US ZIP code

2 ReleaseNumber

Internal unique identifier for release
(lookup in Releases table)1.

3 ChemicalNumber

Internal unique identifier of released chemical
(lookup in Chemical table)1.

4 FacilityNumber

Internal unique identifier of releasing facility
(If media = 1 or 2, then lookup in Facility table;
If media = 6 or 750 or 754, then lookup in Off-site
table)1.

5 Media

Code describing media into which chemical is
released.

(lookup in Media table)1.

6 Cone

Concentration of chemical for release/media at ZIP
code (ng/m3).

7 ToxConc

Concentration multiplied by inhalation toxicity
weight.

8 Score

Risk-related score (estimated dose * toxicity
weight * potentially exposed population).

9 ScoreCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for cancer effects.

10 ScoreNonCancer

Risk-related score (estimated dose * toxicity
weight * potentially exposed population) using
only toxicity values for noncancer effects.

11 Pop

Number of people in ZIP code (may be
interpolated).

1 Other tables can be found in the Public Release Data tables, on the RSEI FTP site (ftp://newftp.epa.gov/RSEI/) or
https://eaftR.epa.eov/RSEI. or in the RSEI data dictionary (https://www.epa.eov/rsei/rsei-data-dictionarv). Be sure to use the

data tables from the same RSEI model version as the Microdata.

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ZIP Code Shapefiles (dbf file)

Field Number

Name

Description

1

GEOID

US ZIP code.

2

NUMFACS

Number of facilities affecting the ZIP code.

3

P NUMFACS

Percentile associated with field NUMFACS.

4

NUMRELEASES

Number of releases affecting the ZIP code.

5

P NUMRELEASES

Percentile associated with field NUMRELEASES.

6

NUMCHEMS

Number of chemicals affecting the ZIP code.

7

P NUMCHEMS

Percentile associated with field NUMCHEM.

8

TOXCONC

Average toxicity-weighted concentration of the
cells in the ZIP code.

9

P TOXCONC

Percentile associated with field TOXCONC.

10

SCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population)
of the cells in the ZIP code.

11

P SCORE

Percentile associated with field SCORE.

16

POP

Sum of the population of the cells in the ZIP code.

17

P POP

Percentile associated with field POP.

12

NCSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population)
of the cells in the ZIP code. Score is calculated
using only noncancer toxicity weights.

13

P_NCSCORE

Percentile associated with field NCSCORE.

14

CSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population)
of the cells in the ZIP code. Score is calculated
using only cancer toxicity weights.

15

P_CSCORE

Percentile associated with field CSCORE.

ZIP Code Aggregated Data (csv file)

Field Number

Name

Description

1

GEOIDIO

US ZIP code.

2

NUMFACS

Number of facilities affecting the ZIP code.

3

NUMRELEASES

Number of releases affecting the ZIP code.

4

NUMCHEMS

Number of chemicals affecting the ZIP code.

5

TOXCONC

Average toxicity-weighted concentration of the
cells in the ZIP code.

6

SCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the ZIP code.

7

POP

Sum of the population of the cells in the ZIP code.

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Field Number

Name

Description

8

CSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the ZIP code. Score is calculated using
only cancer toxicity weights.

9

NCSCORE

Sum of the risk-related scores (estimated dose *
toxicity weight * potentially exposed population) of
the cells in the ZIP code. Score is calculated using
only noncancer toxicity weights.

Water Microdata: Annual Aggregated Shapefiles

Field Number

Name

Description

1

Com ID

"Common Identifier" of a flowline (sub-segment of a
reach)- atomic unit of reach data that matches one-to-
one to NHDPIus.

2

ReachCode

Code for reach

3

ToxConc

Sum of toxicity-weighted concentrations in the
flowline. Concentration is in mg/L.

4

Latl

Latitude of the 25th point of the 100 that constitute a
flowline in NHDPIus.*

5

Longl

Longitude of the 25th point of the 100 that constitute a
flowline in NHDPIus.*

6

Lat2

Latitude of the 50th point of the 100 that constitute a
flowline in NHDPIus.*

7

Long2

Longitude of the 50th point of the 100 that
constitute a flowline in NHDPIus.*

8

Lat3

Latitude of the 75th point of the 100 that constitute a
flowline in NHDPIus.*

9

Long3

Longitude of the 75th point of the 100 that constitute a
flowline in NHDPIus.*

* Note that points may not be evenly spaced.

Water Microdata: All Years Discharges

Field Number

Name

Description

1

ReleaseNumber

Internal unique identifier for release
(links to Releases table).1

2

Counter

Auto-increment count of COMIDs

3

Com ID

"Common Identifier" of a flowline (sub-
segment of a reach)- atomic unit of reach
data that matches one-to-one to NHDPIus.

4

ReachCode

Code for reach

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RSEI Geographic Microdata Documentation

Field Number

Name

Description

5

Cone

Concentration of chemical in flowline
(mg/L)

6

Sequence

Number defining pathway of release (used
to indicate branching).

7

TravelTime

Time(s) for release to go from top of
flowline to bottom.

8

TravelLength

Distance (m) for release to go from top of
flowline to bottom

9

Paths

Number of branches in stream path

10

FCode

Descriptor from NHDPIus for type of
flowline (e.g., pipeline, stream)

11

ResCode

Internal code

12

OTW

Oral toxicity weight for the chemical.

13

ToxConc

Toxicity-weighted concentration in the
flowline for the discharge. Concentration is
in mg/L.

14

NCTW

Noncancer toxicity weight for the chemical.

15

CTW

Cancer toxicity weight for the chemical.

16

Year

Year the discharge occurred.

1 1 Other tables can be found in the public data set, on

the RSEI fto site (ftD://newftD.eca.^ov/RSEI/) or in the RSEI data

dictionary (https://www.eDa.sov/rsei/rsei-data-dictionarv). Be sure to use the data tables from the same RSEI version as the

Microdata.

Census Crosswalk Table

Field Number

Name

Description

1

GridID

Identifies grid.
14=Conterminous US
24=Alaska
34=Hawaii

44=Puerto Rico/Virgin Islands
54=Guam/Marianas
64=American Samoa

2

X

X coordinate of the cell address.

3

Y

Y coordinate of the cell address.

4

BlockJDOO

US Census Block ID.

5

UR

Internal.

6

PCT_B_C

Percent of the Census block that is within the cell
(Block to Cell).

7

PCT_C_B

Percent of the cell that is within the Census block
(Cell to Block).

8

PCT_CP_B

Percent of the cell's population that is within the
Census block (Population-Cell to Block).

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