Risk-Screening Environmental Indicators Version 2.3.1

The Risk-Screening Environmental Indicators (RSEI) Version 2.3.1 is a computer-
based screening tool for the evaluation of toxic chemical emissions and transfers
from industrial facilities. RSEI can quickly assess important factors related to
potential chronic human health risks from industrial pollution and waste
management (chronic effects are associated with low-level and long-term
exposure). Whether a pounds-based, hazard-based, or risk-related perspective is
chosen, the RSEI model delivers results in a matter of minutes or hours that
previously would have required weeks, months, or even longer to produce. RSEI
can help identify opportunities with the greatest potential for hazard or risk
reduction, while saving considerable analytical resources.

What factors does the RSEI Model consider?

The RSEI model uses annual reporting from individual industrial facilities along with
a variety of other information to evaluate chemical emissions and other waste
management activities. RSEI incorporates detailed data from EPA's Toxics
Release Inventory (TRI), the Integrated Risk Information System, the U.S. Census
of population, and other sources. Using existing EPA models, RSEI incorporates
the full spectrum of risk-related factors by considering:

¦	the amounts of toxic chemicals that facilities release;

¦	the environmental concentrations attributable to these releases;

¦	the doses that people receive from these environmental concentrations;

¦	the relative long-term toxicity of these doses; and

¦	the number of people who are affected.

How does the RSEI Model work?

The RSEI model generates unique numerical values known as "Indicator Elements"
using the factors listed above. Indicator Elements are unitless—like an index
number, they can be compared to one-another, but they do not represent actual
risk. Indicator Elements are proportional to the relative risk of each release, with
incrementally higher numbers reflecting greater estimated risk. These elements are
generated for every possible combination of reporting facility, chemical, release
medium, exposure pathway (inhalation or ingestion), and year. They serve as the
building blocks for RSEI and are summed in various ways to produce risk-related
results for scenarios of interest to users.

How can the RSEI Model be used?

As its name implies, RSEI can be used for screening level activities. It does not
serve as a detailed or quantitative risk assessment, but can be used to identify
situations where a more formal risk assessment is needed. RSEI can compare
many of the pertinent risk-related chronic human health aspects associated with
industrial releases of toxic chemicals and can provide risk-related comparisons for
facilities, chemicals, geographic areas, and/or time periods. Results can be
generated for virtually any level of aggregation—from individual facilities to entire
industries, or from local areas to the entire nation. Tracking changes in risk-related
results over time is a way to measure progress in environmental protection and
pollution prevention programs.

RSEI supports ranking and prioritization, strategic planning, targeting, trend

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analysis, and other assessments. Important questions that can be addressed with
RSEI include:

¦	What are the national trends in hazard and risk associated with toxic
chemical releases and other waste management activities at industrial
facilities?

¦	What industries have comparatively more chronic human health risk
associated with them?

¦	What is the relative contribution of specific chemicals to overall risk?

¦	For any given scenario, what release pathway for a particular chemical
poses the greatest risk-related concerns?

Once RSEI addresses the broader questions, it can be used to interpret the risk-
related results and explore which factors contribute most to a given ranking or trend.
RSEI Version 2.3.1 provides a risk-related perspective for air and water releases
(including those from certain off-site transfers) for the 1996-2010 TRI reporting data.
It also provides other valuable perspectives for all release pathways and other
waste management activities at industrial facilities, such as pounds of release and
pounds of release weighted by toxicity (for a hazard-based perspective). RSEI also
provides results for important groups such as children, men and women of
reproductive age, and the elderly. Results can be exported to database or
spreadsheet formats for additional analyses or for use with other data sets. A user-
friendly interface allows the quick display of graphs or tables of information, and the
RSEI Welcome Screen provides tutorials on how to use the model (these tutorials
can also be found in the User's Manual).

Where can I obtain the RSEI Model?

The installation program for RSEI Version 2.3.1 can be downloaded from the RSEI
Home Page atwww.epa.gov/oppt/rsei.

Where is more information available?

The RSEI Home Page at http://www.epa.gov/oppt/rsei/ provides additional
information. This site has information on the RSEI methodology, the comprehensive
peer review of RSEI, important caveats, and the strengths and limitations of the
model. For more specific inquiries, contact the RSEI Team in EPA's Office of
Pollution Prevention and Toxics (OPPT) by email at RSEI_lndicators@epa.gov or
by telephone at (202) 564-8790.

The members of the RSEI Team are

Lynne Blake-Hedges
Richard Engler
Cody Rice


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