United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Publication 9320.7-04 FS
November 1990
&EPA Closing the NPL Book
Under the Original MRS
Office of Emergency and Remedial Response
Hazardous Site Evaluation Division (OS - 230)
Quick Reference Fact Sheet
Since 1982, the U.S. Environmental Protection Agency (EPA) has been preparing the National Priorities List
(NPL). This list informs the public of uncontrolled hazardous waste sites that warrant further investigation to de-
termine if they pose risks to public health or the environment. Such sites are eligible for long-term "remedial action"
financed under the Trust Fund established by the Comprehensive Environmental Response, Compensation, and Lia-
bility Act as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA).
Sites are placed on the NPL
primarily on the basis of their
scores under EPA's Hazard
Ranking System (HRS) model
developed in 1982. EPAhasnow
revised the HRS in response to
SARA. The revised HRS, which
will become effective late in Feb-
ruary 1991,90 days after its pub-
lication in the Federal Register, is
a more comprehensive and ac-
curate scoring system than the
original HRS and will add new
types of sites to the NPL.
During 1981-90, 1,301 sites
were proposed to the NPL, most
of them because their HRS scores
wereabovethe28.5Qcut-off. The
remaining sites were proposed
on the basis of one of two mecha-
nisms that do not require an HRS
score of 28.50 or greater:
• The State has designated a
site as its top priority.
• The Agency for Toxic Sub-
stances and Disease Registry has
issued a health advisory that rec-
ommends removingpeople from
the site, and certain other techni-
cal criteria are met.
EPA proposed 1,301 NPL sites under original HRS
Sites placed on final NPL
Federal Facility Sites (116)
Others (1,071)
Sites remaining on proposed NPL
1,207
m
Sites deleted from final NPL
Sites dropped from proposed NPL
65
Policy Issues
Technical Issues
Sites proposed (1981-1990)
(30)
(35)
total 1,301
HRS Score 28.5 or above (1,259)
State Top Priority (38)
ATSDR Health Advisory (4)
(November 1, 1990)
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NPL has grown since 1981
1500-1
0207)
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
Year
The NPL has grown steadily
over the years. As the original
HRS winds down, 1,187 sites
are on the final NPL, and 20 are
in proposed status. Final action
will be taken on the proposed
sites before the effective date of
the revised HRS.
The growth of the NPL is the
result of Superfund's site assess-
ment process, which starts when
a site is identified and entered
into CERCLIS, EPA's compu-
terized inventory of potential
hazardous waste sites. EPA
identifies sites through a vari-
ety of methods, including rec-
ords and information provided
by States and handlers of haz-
ardous materials, as well as re-
ports from concerned citizens.
Superfund's Site Assessment Program closes the gap
40000 -
35000 -
Jg 30000 -\
(f)
3 25000 -|
O
QC
111
O 20000 -
"o
2 15000 -
3
10000 -
5000
0
68.8%
Percent of CERCLIS sites needing
initial evaluation drops
7.6%
-^B.
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
YMF
Sites in CERCUS
Total Preliminary
Assessments
Completed to Date
Total Site Inspections
Completed to Date
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
Year
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Next, EPA or the State conducts a preliminary assess-
ment (PA), a low-cost review of existing information to
determine if the site poses a potential hazard. If the PA
shows that the site does not present a potential hazard,
no further remedial action is planned under Superfund.
If the site does present a serious imminent threat, EPA
may use the Trust Fund to take immediate "removal"
action.
If the PA shows that an actual or potential contamina-
tion problem exists but does not pose an imminent
threat, EPA will perform a more extensive study called
the site inspection (SI). The SI involves collecting addi-
tional information to better understand the extent of the
problem at the site, to screen out sites that will not qualify
for the NPL, and to obtain data necessary to calculate an
MRS score for sites which warrant placement on the NPL
and further study. The SI usually includes collection and
analysis of environmental and waste samples to deter-
mine what substances are present at the site and whether
they are being released. Following the SI, a site can receive
a decision that no further remedial action is planned
under Superfund, or that it will be scored to determine
whether it should be proposed for the NPL.
Few CERCLIS sites still need initial evaluation
hitial Evaluation Needed
Site Inspection Completed
No Further Remedial Action Pinned
Stte Inspection Completed •
Decision Pending
Preliminary Assessment Completed •
No Further Remedial Action Planned
She Inspection Needed
(November 1,1990)
31,317 of 33,575 (92.4%) sites in CERCLIS
have received initial evaluation.
To date, 92 percent of the more than 33,000 sites in
CERCLIS have received an initial evaluation. Almost
half of the sites in CERCLIS have received a "no further
action" decision.
In the past, the decision on whether a site should con-
tinue on for HRS scoring or be dropped from further
consideration for the NPL may have been delayed for
some time after each evaluation step was completed. As
a result, the program is looking at ways to improve the
technical decision-making process and reduce the time
involved in placing sites on the NPL.
Generally, the site assessment program will follow the
same steps in implementing the revised HRS as it did
with the original HRS, although the information gath-
ered may differ. Standard operating guidance for PA's,
Si's, and HRS packages as well as training sessions are
being developed to guarantee rapid and consistent appli-
cation of the revised HRS. In addition, a "PreScore"
computer program will be used to perform the calcula-
tions required by the HRS. This allows quick sensitivity
analysis to focus SI sampling on the most important HRS
factors, resulting in more nationally consistent, focused,
and better-quality decisions. Another computer program
will automatically supply data to PreScore on over 300
chemicals. These changes will enable EPA to improve the
quality and timeliness of Superfund's evaluation of thou-
sands of potential hazardous waste sites annually and
place the worst on the NPL.
For further information, contact:
Hazardous Site Evaluation Division
Office of Emergency and Remedial Response
Mail Code OS-230
tU», Environmental Protection Agency
401M Street SW
Washington, DC 20460
or
Superfund Hotline, (800) 424-9346 in the continental
U.$., or (202) 382-3000 in the Washington, DC area.
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National Priorities List Sites
1187 FINAL NPL SITES +
20 PROPOSED NPL SITES X
1207 TOTAL NPL SITES
GU-1 +
AK-6+
PR-9+
HI-6X
HI-1 +
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