Risk-Screening Environmental Indicators
(RSEI)
April 8, 2009
RSEI
Introduction
 What is the Risk-Screening Environmental
Indicators (RSEI) Model and How Does It
Work?
 What Kinds of Questions Can RSEI Answer?
 Who is using RSEI?
 Points to Remember
RSEI
What Is the Risk-Screening
Environmental Indicators Model?
RSEI is a screening-level model for assessing potential
chronic human health impacts of industrial releases of
toxic chemicals:
RSEI provides the following types of screening analyses:
 Pounds
 Hazard
 Risk-related
RSEI
Why Risk-Screening Environmental
Indicators?
The Need for Risk Context:
“The determination of potential
risk depends upon many
factors, including the toxicity of
the chemical, the fate of the
chemical, and the amount and
duration of human or other
exposure to the chemical after
it is released.”
Source: Toxics Release Inventory: Factors to Consider When
Using TRI Data, November 2002, emphasis added.
RSEI
RSEI and Risk Assessment
RSEI incorporates components of risk assessment:
 Amount of chemical released
 Fate and transport of the chemical
 Route and extent of human exposure
 Number of people affected
 Toxicity of the chemical
RSEI is not a formal risk assessment—RSEI uses
simplifying assumptions. It is useful for performance
measurement, prioritization, and trend analysis because it
incorporates toxicity and exposure considerations in
addition to amount released.
RSEI
How Does RSEI Work?
RSEI uses:



Toxics Release Inventory data
Existing exposure models and databases
Reviewed toxicity data
RSEI
What Kinds of Questions Can RSEI
Answer?
 What are the trends in hazard and risk scores
associated with toxic chemical releases and other
waste management activities at industrial facilities?
 When comparing industries, how can I rank which
industry sectors are associated with relatively more
potential risk?
 What is the relative contribution of specific
chemicals to the risk score in a community (state,
county, city), and how do I prioritize these for
follow-up activities?
 For any given scenario, what release pathway for a
particular chemical poses the greatest risk-related
concerns?
RSEI
What’s new in RSEI 2.2.0?
• TRI Reporting Years 1996-2006
• AERMOD. Previous versions of RSEI used EPA’s
ISC model to calculated chemical concentrations on
air. Version 2.2.0 uses AERMOD, which EPA fully
promulgated as a replacement to ISCLT in December
2006
• Updated Toxicity Weights for a number of chemicals
and include EPA's Provisional Peer Reviewed
Toxicity Values as a source.
• Include NAICs codes for 2006 data in addition to SIC
codes
• Location and characteristics of drinking water
intakes is now taken from USGS’s Public Supply
Database, instead of EPA’s Safe Drinking Water
Information System (SDWIS).
RSEI
Who is Using RSEI?
 OPPT: Annual Performance Goals; CARE prioritization; Tribal
activities
 OW: Modeling of Exposure from Fish Ingestion
 OECA: Targeting; Prioritization; Environmental Justice
 Regional Offices: Enforcement Prioritization;
Permitting; Environmental Justice
 States: P2 technical assistance; Prioritization
 Academia: Cross-media Risk Transfers;
Environmental Justice; MapEcos
 Private Sector: Tracking environmental performance;
investment analysis
 News Organizations: initial screening of children’s or other
issues
RSEI
Points to Remember
RSEI PROVIDES QUICK PERSPECTIVES ON HAZARD &
RISK, BUT IS ONLY THE FIRST STEP!
 RSEI uses facility-reported TRI data which can contain
reporting errors. Also, if it’s not reported to TRI, it’s not
modeled in RSEI.
 RSEI toxicity weights are based on chronic human
toxicity associated with long-term exposure and do not
address acute human toxicity or environmental toxicity.
 Many indirect exposure pathways not considered.
 TRI, and therefore, RSEI, do not cover all sources of
TRI-listed chemicals (e.g., small businesses, mobile and
agricultural sources).
RSEI
Points to Remember cont.
 Except for chromium, metals and metal
compounds are assumed to be present in the
most toxic form.
 Simplifying assumptions for stack heights,
diameters, and exit gas velocities are used
where facility-specific data are not available.
 RSEI results do not indicate whether hazard or
risk from a chemical or facility is “acceptable” to
a population or individual.
RSEI
Results from V. 2.2.0
2500
120
2000
100
80
1500
60
1000
40
500
Risk Index
(2001 Natl=100)
lbs (million)
Trend in RSEI Score and Pounds
20
0
0
2001
2002
2003
2004
Year
2005
2006
National lbs
National Risk
*This excludes the diisocyanates release from Kairak in 2003.
RSEI
Results from V. 2.2.0
Lead and lead
compounds
Top Chemicals in U.S. (2006)
Proportion Total RSEI Score
Mercury and mercury
compounds
Diisocyanates
Sulfuric acid
Nickel and nickel compounds
Phosphorus (yellow or white)
Polycyclic aromatic compounds
Manganese and
manganese
compounds
Copper and copper compounds
Diaminotoluene (mixed isomers)
All others
RSEI
Contacts
 Lynne Blake-Hedges: (202) 564-8807
blake-hedges.lynne@epa.gov
 Richard Engler:
(202) 564-8587
 Kristen Loughery:
(202) 564-8296
 Cody Rice:
(202) 564-8769
engler.richard@epa.gov
loughery.kristen@epa.gov
URL: http://www.epa.gov/oppt/rsei
RSEI