[Federal Register Volume 67, Number 245 (Friday, December 20, 2002)]
[Notices]
[Pages 77981-77994]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-31672]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-7421-4]


Notice of Intent To Grant an Exemption for the Injection of 
Certain Hazardous Wastes to Environmental Disposal Systems, Inc. for 
Two Injection Wells Located at 28470 Citrin Drive, Romulus, MI

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: The United States Environmental Protection Agency, Region 5, 
Chicago office, proposes (through this notice) to grant an exemption 
from the ban on disposal of hazardous wastes through injection wells to 
Environmental Disposal Systems Inc. (EDS) of Birmingham, Michigan. If 
the exemption is granted, EDS may inject all Resource Conservation and 
Recovery Act (RCRA) regulated hazardous wastes through waste disposal 
wells 1-12 and 2-12. The regulations promulgated 
under the Hazardous and Solid Waste Amendments to RCRA, prohibit the 
injection of restricted hazardous waste into an injection well. Persons 
seeking an exemption from the prohibition must submit a petition 
demonstrating that, to a reasonable degree of certainty, there will be 
no migration of hazardous constituents from the injection zone for as 
long as the waste remains hazardous.
    On January 21, 2000, EDS submitted a petition to the EPA, Region 5, 
Chicago office, seeking an exemption from the ban based on a showing 
that any fluids injected will not migrate vertically out of the 
injection zone or laterally to a point of discharge or interface with 
an underground source of drinking water (USDW) within 10,000 years. The 
EPA has conducted a comprehensive review of the petition, its 
revisions, and other materials submitted and has determined that the 
petition submitted by EDS, as revised on October 3, 6, 27, and 31, 
2000; January 12, April 24, and October 16, 2001; and January 31 August 
22, September 25, and October 23, 2002, meets the requirements of 40 
CFR part 148, subpart C.

DATES: The EPA, Region 5, Chicago office, requests public comments on 
today's proposed decision. Comments

[[Page 77982]]

will be accepted until January 22, 2003. Comments post-marked after the 
close of the comment period will be stamped ``Late.'' Late comments do 
not have standing and will not be considered in the decision process. 
EPA will schedule a public hearing to allow comment on this proposed 
action. EPA will publish a notice of this hearing in a local paper and 
send it to people on its mailing list. If you wish to be notified of 
the date and location of the public hearing please contact the person 
listed below. EPA will cancel the hearing if it has no evidence of a 
need for a hearing.

ADDRESSES: Submit written comments, by mail, to: Ms. Sally Swanson, 
Acting UIC Branch Chief, United States Environmental Protection Agency, 
Region 5, Underground Injection Control Branch (WU-16J), 77 West 
Jackson Boulevard, Chicago, Illinois 60604-3590; or, to use e-mail, 
direct comments to [email protected].

FOR FURTHER INFORMATION CONTACT: Mr. Harlan Gerrish, Lead Petition 
Reviewer, at the same address, Office Telephone Number: (312) 886-2939, 
or, to use e-mail, direct comments to [email protected].

SUPPLEMENTARY INFORMATION:

I. Background

A. Authority

    HSWA, which was enacted on November 8, 1984, imposed substantial 
additional responsibilities on those who handle hazardous waste. The 
amendments prohibit the land disposal of untreated hazardous waste 
beyond specified dates, unless the EPA determines that the prohibition 
is not required in order to protect human health and the environment 
for as long as the waste remains hazardous (RCRA section 3004(d)(1), 
(e)(1), (f)(2), (g)(5)). RCRA specifically defines land disposal to 
include any placement of hazardous waste into an injection well (RCRA 
section 3004(k)). After the effective date of prohibition, hazardous 
waste can only be injected under two circumstances:
    (1) When the waste has been treated in accordance with the 
requirements of 40 CFR part 268 as required by section 3004(m) of RCRA, 
(the EPA has adopted the same treatment standards for injected wastes 
in 40 CFR part 148, subpart B); or
    (2) When the owner/operator has demonstrated that, to a reasonable 
degree of certainty, there will be no migration of hazardous 
constituents from the injection zone for as long as the waste remains 
hazardous. Applicants seeking an exemption from the ban must 
demonstrate that the hydrogeological and geochemical conditions at the 
site and the physicochemical nature of the waste stream(s) are such 
that reliable predictions can be made either:
    (a) That fluid movement conditions are such that the injected 
fluids will not migrate within 10,000 years: (1) Vertically upward out 
of the injection zone; or (2) laterally within the injection zone to a 
point of discharge or interface with an Underground Source of Drinking 
Water (USDW) (the no-migration standard); or
    (b) That before the injected fluids migrate out of the injection 
zone or to a point of discharge or interface with USDW, the fluid will 
no longer be hazardous because of attenuation, transformation or 
immobilization of hazardous constituents within the injection zone by 
hydrolysis, chemical interactions or other means.
    EDS has submitted a petition that uses mathematical models to 
demonstrate that the injected fluids will not migrate within 10,000 
years.
    The EPA published regulations setting forth the requirements for 
petitions for exemption from the disposal prohibition in the Federal 
Register on July 26, 1988 (53 FR 28118). The demonstrations are based 
on direct measurements of geological properties of the injection zone 
made during the construction and subsequent testing of the wells at the 
EDS facility on Citrin Drive or on values measured at similar locations 
where conditions can be expected to be near equivalents. Because the 
model encompasses a region which is much larger than sampling 
techniques employed along and between the well bores can reach, the 
demonstration allows for uncertainty by using values which are more 
conservative than those which the petitioner believes are most 
appropriate. The measurements are used to create a conceptual model of 
the geological framework into which waste is injected. Models must 
account for such geological properties as the porosity, permeability, 
and compressibility of the strata within the injection zone which will 
serve as the reservoir and the strata which are expected to confine the 
waste within the injection zone. Characteristics, such as density and 
viscosity, of the brine currently within the injection zone and of the 
waste which will be injected are also considered. Equations have been 
developed to calculate the pattern and extent of pressure increase 
resulting from injection for many different geologic models. When the 
proposed injection is simulated, computer programs use the appropriate 
equations to calculate the amount and distribution of increased 
pressure in the disposal reservoir. The distance which fluid and then 
independent molecules of the injected waste will move through the 
reservoir and confining zone are also calculated.
    During the period of injection, fluids are pumped through the 
injection wells into porous geological formations at pressures which 
are sufficient to force the fluids to flow thousands of feet into the 
formations. In most cases, the operator of a particular group of 
injection wells controls the only injection occurring in the area. If 
there are other nearby injection or production wells, however, they 
will also affect how fluids move.
    Injection moves the fluids at a relatively high velocity. This 
movement slows immediately, but continues at greatly reduced speed for 
a time after injection ends. The length of that time is approximately 
equal to the length of the injection phase. By the end of that time, 
the continued movement has allowed the hydraulic pressures around the 
injection wells to return to the pre-injection level, if it is a large 
injection formation. After the pressure dissipates, significant 
movement of waste fluid results from three phenomena: Natural 
background or regional flow, density differences, and diffusion of 
individual molecules through geological materials.
    The simulation of waste movement is carried forward for a period of 
10,000 years. EPA chose a time limit of 10,000 years for the 
demonstration because a demonstration over that time period would both 
suggest containment for a substantially longer time period and a 
10,000-year time frame would allow time for geochemical transformations 
which might render the waste nonhazardous or immobile. (See 53 FR 
28126). The EPA's Science Advisory Board agreed that the 10,000 year 
time frame is appropriate in a 1984 study dealing with the storage of 
radioactive wastes. The EPA's standard does not imply that leakage will 
occur at some time after 10,000 years. It requires a demonstration that 
leakage will not occur within that time frame. Understanding geological 
factors such as the permeability of intact rock, the presence of 
transmissive fractures, and the identification of artificial 
penetrations of the confining zone provides the key to constructing an 
accurate model and performing a valid simulation. Because 10,000 years 
is a relatively short interval of geologic time, we assume that only 
the three phenomena listed above affect the rate of movement. Each of 
these phenomena is well understood, and their effects can be 
calculated. If the simulation

[[Page 77983]]

establishes that the injected waste will not escape a defined volume of 
rock which is some distance below the USDWs or discharge to a USDW for 
a period of 10,000 years, the operation meets the regulatory no 
migration standard.

B. Facility Operation

    EPA previously issued permits to the proposed EDS facility to 
commercially dispose of liquid wastes by deep well injection. The 
operator has constructed two wells. The proposed exemption is based on 
a long term average injection rate, for the facility as a whole, of 166 
gallons per minute (gpm) averaged over one-month periods for a total of 
7,275,780 gallons per month. The instantaneous injection rate may reach 
270 gpm for the facility. The long term average rate limit is used to 
bound the area of the waste plume so that the plume will be no larger 
than the area estimated in the petition. The instantaneous limit will 
allow EDS to inject more waste for some periods of time than others to 
accommodate deliveries during normal business hours and other 
occurrences. The rate at which EDS may inject is also limited by the 
maximum allowable surface injection pressure.
    The conservative nature of the demonstration is a significant 
aspect of the demonstrations. The result of the simulations which 
comprise the demonstration are not predictions of the distance to which 
the hazardous waste plume will move. Rather, they are predictions of a 
distance beyond which movement will not occur. That is, the actual 
distance of movement is expected to be considerably less than that 
simulated.

C. Submission

    On January 21, 2000, EDS submitted a petition for exemption from 
the land disposal restrictions of hazardous waste injection under the 
HSWA of RCRA. EPA reviewed this submission for completeness and 
provided comments. EPA received revised documents on October 3, 6, 27, 
and 31, 2000; January 12, April 24, and October 16, 2001; and January 
31, August 22, September 25, 2002 and October 23, 2002, responding to 
EPA comments.

II. Basis for Determination

A. Waste Description and Analysis (40 CFR 148.22)

    Under the proposed exemption, EDS can inject wastes from a variety 
of industrial sectors and processes including: pharmaceutical 
production, steel pickling operations, automobile parts fabrication, 
and other commercial disposal operations at facilities which do not 
have the means to dispose of hazardous liquid wastes. EDS has 
petitioned the EPA, Region 5, to grant an exemption to allow injection 
of wastes bearing the following RCRA waste codes:

[[Page 77984]]



                                                                                             List of RCRA Waste Codes Approved for Injection
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D001     D022     D043     F027     K015     K036     K071     K106     K141     K174     P017    P042    P067    P094    P118    P203    U020    U042    U064    U086    U109    U130    U151    U172    U194    U210    U249    U382
D002     D023     F001     F028     K016     K037     K073     K107     K142     K175     P018    P043    P068    P095    P119    P204    U021    U043    U066    U087    U110    U131    U152    U173    U196    U220    U271    U383
D003     D024     F002     F032     K017     K038     K083     K108     K143     K176     P020    P044    P060    P096    P120    P205    U022    U044    U067    U088    U111    U132    U153    U174    U197    U221    U277    U384
D004     D025     F003     F034     K018     K039     K084     K109     K144     K177     P021    P045    P070    P097    P121    U001    U023    U045    U068    U089    U112    U133    U154    U176    U200    U222    U278    U385
D005     D026     F004     F035     K019     K040     K085     K110     K145     K178     P022    P046    P071    P098    P122    U002    U024    U046    U069    U090    U113    U134    U155    U177    U201    U223    U279    U386
D006     D027     F005     F037     K020     K041     K086     K111     K147     P001     P023    P047    P072    P099    P123    U003    U025    U047    U070    U091    U114    U135    U156    U178    U202    U225    U280    U387
D007     D028     F006     F038     K021     K042     K087     K112     K148     P002     P024    P048    P073    P101    P127    U004    U026    U048    U071    U092    U115    U136    U157    U179    U203    U226    U328    U389
D008     D029     F007     F039     K022     K043     K088     K113     K149     P003     P026    P049    P074    P102    P128    U005    U027    U049    U072    U093    U116    U137    U158    U180    U204    U227    U353    U390
D009     D030     F008     K001     K023     K044     K093     K114     K150     P004     P027    P050    P075    P103    P185    U006    U028    U050    U073    U094    U117    U138    U159    U181    U205    U228    U359    U391
D010     D031     F009     K002     K024     K045     K094     K115     K151     P005     P028    P051    P076    P104    P188    U007    U029    U051    U074    U095    U118    U139    U160    U182    U206    U234    U364    U392
D011     D032     F010     K003     K025     K046     K095     K116     K156     P006     P029    P054    P077    P105    P189    U008    U030    U052    U075    U096    U119    U140    U161    U183    U207    U235    U365    U393
D012     D033     F011     K004     K026     K047     K096     K117     K157     P007     P030    P056    P078    P106    P190    U009    U031    U053    U076    U097    U120    U141    U162    U184    U208    U236    U366    U394
D013     D034     F012     K005     K027     K048     K097     K118     K158     P008     P031    P057    P081    P108    P191    U010    U032    U055    U077    U098    U121    U142    U163    U185    U209    U237    U367    U395
D014     D035     F019     K006     K028     K049     K098     K123     K159     P009     P033    P058    P082    P109    P192    U011    U033    U056    U078    U099    U122    U143    U164    U186    U210    U238    U372    U396
D015     D036     F020     K007     K029     K050     K099     K124     K160     P010     P034    P059    P084    P110    P194    U012    U034    U057    U079    U101    U123    U144    U165    U187    U211    U239    U373    U400
D016     D037     F021     K008     K030     K051     K100     K125     K161     P011     P036    P060    P085    P111    P196    U014    U035    U058    U080    U102    U124    U145    U166    U188    U213    U240    U375    U401
D017     D038     F022     K009     K031     K052     K101     K126     K169     P012     P037    P062    P087    P112    P197    U015    U036    U059    U081    U103    U125    U146    U167    U189    U214    U243    U376    U402
D018     D039     F023     K010     K032     K060     K102     K131     K170     P013     P038    P063    P088    P113    P198    U016    U037    U060    U082    U105    U126    U147    U168    U190    U215    U244    U377    U403
D019     D040     F024     K011     K033     K061     K103     K132     K171     P014     P039    P064    P089    P114    P199    U017    U038    U061    U083    U106    U127    U148    U169    U191    U216    U246    U378    U404
D020     D041     F025     K013     K034     K062     K104     K136     K172     P015     P040    P065    P092    P115    P201    U018    U039    U062    U084    U107    U128    U149    U170    U192    U217    U247    U379    U407
D021     D042     F026     K014     K035     K069     K105     K140     K173     P016     P041    P066    P093    P116    P202    P119    U041    U063    U085    U108    U129    U150    U171    U193    U218    U248    U381    U408
         .......  .......  .......  .......  .......  .......  .......  .......  .......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  U409
         .......  .......  .......  .......  .......  .......  .......  .......  .......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  U410
         .......  .......  .......  .......  .......  .......  .......  .......  .......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  ......  U411
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[[Page 77985]]

B. Well Construction and Operation (Sec.  148.22)

    EDS plans to operate the disposal wells for at least 20 years. The 
physics of well injection is well understood because of theoretical 
studies conducted by oil production companies and observations through 
the long history of injection and production in oil fields. EPA has 
developed the UIC program under the Safe Drinking Water Act to prevent 
underground injection which endangers USDWs. The program regulates 
construction and operation of most injection wells. The regulations 
impose extra requirements on hazardous waste injection wells. The 
operations of wells used for the disposal of hazardous wastes are 
subject to an exacting permitting program, monthly review of monitoring 
records, and periodic testing of the well and disposal reservoir. 
Additional safeguards, such as those set forth in the proposed 
decision, are also imposed.
    Figure 1 includes a schematic diagram of the construction of Well 
2-12 and the formations penetrated by the wells. The EDS wells 
have been constructed using four strings of steel casing for each well. 
As the wells were drilled, increasingly smaller casings were placed in 
the well and cemented to the surface. The first cemented casings are 20 
(in 1-12) and 16 (in 2-12) inches in diameter and 
were set at 119 and 177 feet, respectively, to stabilize the well bores 
through the unconsolidated glacial drift. The second strings of casing 
are 13\3/8\ inches in diameter and were set at 396 and 598 feet, 
respectively, to prevent loss of drilling fluid into cavernous zones in 
the shallow bedrock. The third strings of casing were planned to 
provide the safest possible conduit through the near-surface USDWs. 
These casings are 9\5/8\ inches in diameter and are set at 824 and 1444 
feet, respectively. The final casing is set from the surface to within 
the top of the formations which will be used as the waste reservoir. 
These casings are 7 inches in diameter and are set at 4,080 and 3,983 
feet, respectively. The space around each of the casings was sealed 
with cement from the base of the casing to the surface. Cementing 
eliminates potential avenues for either the injected fluid or fluid 
from other, shallower zones to flow outside the casings and into USDWs.
    EDS will inject the waste through a tubing set on a packer and 
isolated from the casing by a fluid-filled annulus, which will be 
continuously monitored for pressure change. The monitoring system is 
designed to trigger alarms and shut off injection if the injection 
pressure exceeds the maximum permitted levels, or if the difference 
between the injection and annulus pressures falls below the minimum 
permitted level.
    Thus, the integrity of the construction will be monitored 
constantly by measuring the pressure within the annulus between the 
casings and tubing and tracking the amounts of liquid added to or 
removed from the annulus system. Even a small leak should be detected 
before environmental injury occurs. More rigorous annual testing 
ensures that even very small leaks are discovered. The pressure in the 
annulus will be maintained at a higher level than the pressures in 
either the formations outside the casing or within the injection 
tubing. Therefore, even if a leak occurs, the waste will not leak into 
the annulus; instead, annulus fluid will leak into the injection tubing 
through which waste is being injected and be carried downward into the 
waste disposal reservoir or, in the case of a casing leak, annulus 
fluid, not waste, will leak into the formations surrounding the well.
    As described, the construction provides for a replaceable tubing 
and a system to detect when replacement of the tubing is necessary. The 
tubing prevents the waste from contacting all except the lowermost few 
tens of feet of casing, which are made of a corrosion resistant alloy. 
The three casing strings and layers of cement through the fresh water 
bearing formations provide extra protection from contamination.
    In order to ensure that the wastes, once safely injected into the 
disposal formation, remain there, the UIC program regulates injection 
pressure and waste properties, and requires regular testing of the 
integrity of injection wells' construction. The injection pressure is 
important because injection pressure drives fluid movement through both 
the reservoir rock and the overlying confining rock. No rock is 
completely impermeable. Because the confining rock is usually less than 
one thousandth as permeable as reservoir rock, the distance of vertical 
movement through the confining rock is less than one thousandth as 
great as the horizontal movement through the reservoir rock. If 
sufficiently high, the injection pressure will fracture the reservoir 
rock and, at higher pressures, may fracture the confining rock. 
Therefore, EDS conducted tests during well construction to measure the 
resistance of the rock of the injection and confining zones to 
fracturing. These tests showed that injecting at pressures below 903 
pound per square inch (psi) measured at the surface will not create 
fractures in the injection zone. The permits are being modified to 
limit the injection pressure at the surface to 903 psi.
    The permits for the injection wells will limit the rate of 
injection, the pressure at which injection takes place, and the 
concentration of hazardous constituents to ensure that the actual 
conditions under which injection occurs are less likely to cause 
increased migration of hazardous constituents than those proposed and 
simulated as described in section F of this Fact Sheet. This will 
ensure that injected wastes will remain in the disposal formations, at 
depths below 3,700 feet, for at least 10,000 years.
    Information available includes results of testing a well which EDS 
drilled in 1993, four miles away from the locations of wells 
1-12 and 2-12. This well is the nearest well drilled 
into the Mt. Simon, Eau Claire, and lower Franconia Formations, which 
will serve as reservoirs; or into the upper Franconia-Dresbach, 
Trempealeau, Greenwood, and lower Black River Formations, which will 
serve as the arresting interval for wastes injected by EDS. Information 
from this well and other wells in Michigan and Ohio was used to 
determine the extent and shape of the important geological formations. 
Other nearby wells tend to go no deeper than the Trenton Formation 
which was penetrated at about 2,950 feet in the EDS wells.
    Additional information was gained through testing of the new wells. 
Among other information, the UICB reviewers looked at the distribution 
of porosity and permeability along the well bore, the hydrostatic 
pressure in the reservoirs to be used for disposal, and the fracture 
opening and closure pressures in the disposal formation as well as in 
the overlying formations. The interaction of these factors determines 
the rate at which waste can be injected without having effects on the 
injection zone that can result in vertical movement through created 
fractures. The cementing and condition of the casing were also reviewed 
and found adequate.

C. Mechanical Integrity Test Information

    The mechanical integrity tests described below were witnessed by 
EPA's contract inspectors. The test records were examined by UICB 
employees who recorded their observations and concluded that the tests 
were successfully passed.
    To assure that the waste does not leak from the tubing prior to 
reaching the injection zone, 40 CFR 148.20(a)(2)(iv) requires 
submission of results from a

[[Page 77986]]

satisfactory annulus pressure test and a Radioactive Tracer Survey to 
test the cement seal at the base of the casing which were performed 
within one year of petition submission. On April 4, 2002, EDS used a 
pressure test to demonstrate the absence of leaks in the casing, tubing 
and packer of well 1-12 by forcing water into the annulus to 
create a pressure of 1,130 psi and then closed the valve used to add 
water to the annulus. The test standard is a pressure change of less 
than 3% in one hour. The pressure declined by 11 psi, which is just 
less than 1%. On April 4, 2002, EDS tested the construction of well 
2-12 by using 1,110 psi. The pressure declined to 1,090 psi. 
Twenty psi is about 2%, so both wells passed the test and demonstrated 
the absence of leaks in the tubing and casing, and packers. This aspect 
of mechanical integrity (MI) is discussed in the federal regulations at 
40 CFR 146.8(a)(1). The sealing of the casing to the rock surrounding 
the well bore immediately above the injection interval was tested using 
a short-lived radioactive (RA) tracer material which was carried deep 
into each well by a geophysical logging tool lowered into the wells on 
a cable on January 8, 2002, in the case of well 1-12, and on 
December 6, 2001, in the case of well 2-12. The tracer was 
released during injection of fresh water. The same tool which releases 
the tracer also contains detectors that are used to trace the movement 
of the RA tracer. If the cement sealing the well bore is not sound, RA 
material will go up the well bore outside the casing. The logging tool 
is used to determine the depth to which the tracer moves before it 
leaves the well bore. There was no indication of upward movement during 
either test. Both of these tests will be repeated annually.
    In addition, EDS made temperature measurements at short intervals 
along the well bores to determine if liquid is moving from any 
formations penetrated by the well, along the well bore, and into a 
USDW. New temperature logs will be made at five-year intervals. These 
two tests (radioactive tracer surveys and temperature logs) offer very 
effective means of determining whether the injected waste remains in 
the injection zone.

D. Site Description

    The EDS injection wells are located at 28470 Citrin Drive within 
the City of Romulus in Wayne County, Michigan, near Detroit.
1. Geological Location
    Geologically these wells are located on the eastern edge of the 
Michigan Basin. Locally, dip is to the northwest at about 100 feet per 
mile. About 4,350 feet of Paleozoic sedimentary rocks covered by about 
100 feet of glacially deposited materials overlie the granitic 
Precambrian basement.
    The injection wells at the EDS facility have approximately 2,980 
feet of separation between the lowermost USDW, found in the Detroit 
River Formation, less than 390 feet below the surface, and the top of 
the injection zone 3,369 feet below the surface (See Figure 1). This 
separation zone is composed of dolomites, shales, sandstones and 
siltstones which are predominantly characterized by low permeability at 
this location. Pressure bleed-off zones are an important factor in the 
containment of wastes. All sedimentary formations are made up of 
horizontal layers which have differing permeabilities. Layers with low 
permeability retard upward movement and layers with high permeability 
allow both upward and horizontal movement. Because upward movement is 
resisted again and again by layers with low permeability, fluids tend 
to flow horizontally. As a result, the pressure which drives the 
movement is reduced by the horizontal flow which occurs in any layer 
having higher permeability than the layer above it. The regulations 
require at least one major permeable bleed-off zone between the 
injection zone and the base of the USDWs. At the EDS facility, the 
major bleed-off zones are the White Niagaran between 2,133 and 2,227 
feet and the Sylvania Sandstone between 400 and 550 feet below the 
surface. In addition, numerous other zones are composed of sand or 
dolomitized limestone which have sufficient porosity and permeability 
to function as pressure bleed-off zones.
    Seismicity. Michigan is an area of low seismic risk. Earthquakes 
felt in Michigan have been generally minor. Moreover, the steel casings 
of deep injection and production wells are more flexible and resilient 
than the rock through which they pass. As a result, they are not 
damaged as a result of earthquakes unless actually sheared as a result 
of movement along a fault which they penetrate as demonstrated by wells 
in seismically active areas like California and Alaska. Because the 
Midwestern earthquakes are widely scattered, with none reported in the 
immediate vicinity of the EDS location, and have epicenters deep within 
the Precambrian granitic rocks far below the injection reservoir, there 
is virtually no possibility of damage as a result of seismic activity.

2. Injection Zone Description

    The injection zone must have reservoir strata with sufficient 
permeability, porosity, thickness, and areal extent to allow the 
injected fluid to be distributed through a large volume of rock so that 
there is no long term increase in pressure in the injection zone. Above 
the reservoir zone, the injection zone must have strata which have low 
vertical permeability and are continuous across the area within which 
the reservoir strata will be affected by injection. These are called 
arresting strata, and they prevent upward movement of wastes from the 
injection zone to USDWs or the surface.
    The injection zone for the EDS facility is between 3,369 and 4,468 
feet below the surface. It consists of 900 feet of reservoir and 
overlying arresting strata, and includes upper Precambrian rocks at the 
base and the Mt. Simon, Eau Claire, Franconia-Dresbach, Trempealeau, 
Glenwood, and lower Black River Formations (See Figure 1). EDS has 
subdivided the injection zone into an injection interval and an 
arrestment interval. The Mt. Simon, Eau Claire, and Franconia-Dresbach 
Formations at depths from 3,937 to 4,550 feet below the surface will 
actually contain the injected wastes. They make up the injection 
interval. The Trempealeau, Glenwood and Black River Formations between 
3,369 and 3,937 feet below the surface will prevent the waste from 
moving upward. They make up the arrestment interval. Each of these 
formations extends far beyond the vicinity of the EDS facility. The Mt. 
Simon and Eau Claire Formations reach the surface in Wisconsin, 
hundreds of miles from the EDS facility.
    Waste is injected directly into the injection interval from the 
open-hole portion of the waste disposal wells. The Mt. Simon and Eau 
Claire Formations are composed of sandstones interbedded with 
siltstone, limestone, dolomite, and shale. These formations contain a 
number of zones which appear capable of accepting injected waste. The 
lower limit for porosity of rock which seems to accept injected liquids 
is 12%. The open-hole geophysical logs identified a total of 255 feet 
of section with porosity greater than 12%.
    The permeability for the receptive intervals of the Eau Claire and 
Mt. Simon as a whole has been calculated by analyzing the pressure 
changes occurring during injection tests. A two-layer model was 
required in order to simulate the pressures actually recorded. The two 
layers are actually a summation of the effects of numerous layers, some 
with higher permeability

[[Page 77987]]

and some with lower. The zones with higher permeability can be 
described as 33 feet in thickness with an average permeability of 400 
millidarcies (md). The zone with lower permeability can be described as 
190 feet thick with an average permeability of 63.43 md.
    The arresting interval is the portion of the injection zone above 
the injection interval, and contains dense carbonates and shale units 
with low permeability and porous carbonates and sandstones which are 
pressure bleed-off units. EDS calculated an average permeability for 
the arresting interval by calculating the harmonic average of vertical 
permeability measurements from the core samples having less than 12% 
porosity. That analysis concluded that the effective vertical 
permeability of the arresting interval is less than 0.005 md.
    Fracture logging of the three wells drilled by EDS indicated 
several sub-vertical fractures in the arresting interval. These 
fractures have limited height and appear to be filled by mineral 
deposits, and do not compromise the integrity of the arresting 
interval. Because there are no known transmissive fractures or faults 
in the arresting interval, it is suitable for long term waste 
retention.
3. Confining Zone Description
    In addition to the arresting strata within the injection zone, the 
injection zone must be overlain by a second series of strata which are 
sufficient to prevent upward fluid movement. These strata are known as 
the confining zone. Like the arresting interval, the confining zone 
must be (1) laterally continuous, (2) free of transecting, transmissive 
faults or fractures over an area sufficient to prevent fluid movement, 
and (3) of sufficient thickness and lithologic and stress 
characteristics to prevent vertical propagation of fractures. The 
immediate confining zone above the injection zone at EDS is made up of 
the upper Black River Limestone, the Trenton Formation, and the Utica 
and Cincinnatian Shales which are found between 2,364 and 3,369 feet 
(See Figure 1). This confining zone is 1,000 feet in thickness, and the 
top is at an elevation 2,000 feet below the lowermost USDW. No 
fractures were detected in the well bores and no transmissive faults or 
fractures are otherwise known to exist in the confining zone within the 
area of review.
    The confining zone will resist vertical migration because of its 
low natural permeability. The confining zone must be separated from the 
lowermost USDW by at least one sequence of permeable and less permeable 
strata that will provide added layers of protection by either providing 
additional confinement (low permeability units) or allowing pressure 
bleed-off (high permeability units). Overlying the confining zone, the 
Clinton Formation is made up of shales and dolomite having low porosity 
and permeability. The Salina Formation contains thick beds of dense, 
plastic anhydrite and salt separated by dolomite, some of which is 
porous and permeable, and shale between 1,300 and 2,100 feet. The 
anhydrite and salt offer very effective barriers to fracturing and flow 
because they deform plastically under the weight of the overlying 
formations to reseal any void space. The White Niagaran between 2,133 
and 2,227 feet is a dolomite which the well site geologist described as 
``a new disposal formation'' in a letter mailed to the EPA on December 
27, 2001. In addition, the Sylvania Sandstone between the depths of 400 
and 550 feet is a thick, porous, and permeable formation which has been 
used extensively as an injection zone in the area. It is capable of 
accepting large amounts of fluid without developing hydrostatic 
pressures which would be high enough to either fracture it or even 
cause formation water to flow through an open conduit into the USDW. 
The layers are continuous for hundreds of square miles. They provide 
the added layers of protection required by the regulations.
4. Geochemical Conditions
    The petitioner must adequately characterize the injection and 
confining zone fluids and rock types to determine the waste stream's 
compatibility with these zones. The injection zone is composed mainly 
of quartz sandstone, with minor amounts of siltstone and dolomite. 
These rock types are known to be resistant to most chemical attack. 
These Mt. Simon rock types are found in all wells which inject into the 
Mt. Simon. Periodic measurements in other wells injecting corrosive 
wastes into the Mt. Simon do not show changes in the size and shape of 
the well bores. Because these rocks generally are very resistant to 
chemical degradation, we anticipate little, if any, compatibility 
problems. To alleviate any problems that may arise from reactions 
between the native formation fluids and the injected wastes, EDS will 
inject fresh water to serve as a buffer between the formation water and 
the injectate before it begins to inject wastes and between injecting 
each batch of waste. The fresh water buffers will prevent wastes which 
might react with each other to form solids from mixing in the near 
well-bore region and will dilute the mixtures when they do come into 
contact as a result of mixing due to dispersion so that the possibility 
of reactions will be reduced. The confining zone is composed of silty 
shale and shaley dolomite. The injected fluid should have little effect 
on the dolomitic layers because dolomite does not react with dilute 
acids at the temperatures which will exist in the injection zone. The 
shale layers are very stable and will be essentially unaffected by 
contact with the injectate.
5. Wells in Area of Review
    Under 40 CFR 146.63, the area of review (AOR) of class I hazardous 
waste wells is a two-mile radius around the well bore or a larger area 
specified by EPA based on the calculated cone of endangering influence 
of the well. The cone of endangering influence is the area within which 
pressurizing the injection interval can raise a column of formation 
fluid or injected fluid sufficiently to cause contamination of a USDW. 
When calculated using values for geological parameters which are 
accepted as most likely to be representative of actual conditions, the 
cone of endangering influence for the EDS injection wells has a radius 
of 23,275 feet, or 4.4 miles from the center of the line between the 
two wells. However, because this did not represent a worst-case 
scenario, EDS used more conservative values and calculated an enlarged 
cone of endangering influence which reaches 32,280 feet from the center 
of the line connecting the two wells. Under 40 CFR 148.20(a)(2)(ii), a 
petitioner must locate, identify, and ascertain the condition of all 
wells within the injection well's area of review that penetrate the 
injection zone or the confining zone. EDS conducted a well search over 
the larger cone of endangering influence consistent with the 
requirements of 40 CFR 148.20(a)(2)(ii) and 146.64, and identified two 
wells penetrating the confining zone and/or injection zone. As 
discussed below both of these wells have been properly plugged, 
completed or abandoned so no corrective action is required under 40 CFR 
148.20(a)(iii) and 146.64.
    The McClure Oil Co. Fritsch et al. 1 is located about 4.5 
miles south of the EDS site. That well was drilled to a depth of 2,885 
feet in 1955 and then plugged with heavy mud with a bridge plug at 1750 
feet. The plugging was approved on July 21, 1955, by the Michigan 
Department of Conservation. This well has been properly abandoned, and 
there is no potential for fluids to move through a conduit. Moreover, 
the maximum depth of this well is almost

[[Page 77988]]

800 feet above the reach of the predicted upward migration of waste 
from the EDS well.
    The second well, the EDS 1-20, was drilled by EDS in 1993 
at a site which was to be used for the facility under review. This 
well, which was properly completed pursuant to an EPA UIC permit, 
penetrates the entire injection zone. The lower portion of the well has 
been plugged using a cast iron bridge plug above the injection zone 
with 50 feet of cement on top of the bridge plug. This meets Region 5's 
standards for plugging wells within the AOR, and will prevent the 
well's casing from serving as a conduit for the movement of fluids from 
the injection zone. Moreover, on January 12, 1999, EDS entered into a 
Stipulation and Consent Agreement with the Michigan Department of 
Environmental Quality (MDEQ). This agreement authorizes EDS 1-
20 to remain inactive and not be considered abandoned, so long as all 
applicable requirements are met, until 30 days after EDS' receipt of 
all MDEQ approvals for the Citrin Drive facility. The agreement 
requires EDS to permanently plug and abandon the well within that 30-
day period. When the well is abandoned, the EPA UIC permit for well 
1-20 requires that the well must be properly plugged and 
abandoned under a plan approved by EPA. Well  1-20 is properly 
completed, is not abandoned, and will be permanently plugged and 
abandoned pursuant UIC requirements. Therefore, a corrective action 
plan under 40 CFR 148.20(a)(iii) and 146.64 is not required.
    It is probable that Sun Pipe Line Company will drill at least one 
injection well slightly more than one half mile from the nearest EDS 
well. Region 5 issued a permit for the construction of a well to be 
used for the injection of non-hazardous salt brine about 2,800 feet 
northeast of the nearest EDS well. Any injection wells which the Sun 
Pipe Line Company drills will be constructed to standards approved by 
Region 5 for the protection of USDWs and the construction will be 
overseen by Region 5's contract inspectors.
    Because no wells penetrating the confining zone or injection zone 
are improperly plugged, completed or abandoned, a corrective action 
plan is not required under 40 CFR 146.64 and 148.20(a)(2)(iii).
6. Absence of Known Transmissive Faults
    There are no known transmissive faults in the Glenwood, 
Trempealeau, and Franconia Formations, the strata within the injection 
zone that will confine fluid movement. Moreover, the interference test 
conducted on June 12-15, 2002, indicates that there are no transmissive 
fractures cutting the injection interval within the area between and 
near the wells.

E. The Use of Predictive Models to Demonstrate No Migration

    The most practical and credible means for petitioners to 
demonstrate no migration of hazardous constituents from the injection 
zone is through the use of predictive mathematical models.
1. Conceptual Models
    As discussed in the preamble to the final rule for petitioning for 
exemption, no-migration demonstrations rely upon conservative modeling 
techniques to evaluate the potential for migration of hazardous 
constituents from the injection zone. Fluid flow modeling is a well-
developed and mature science and has been used for many years in the 
petroleum industry. A wide range of models exists that provide the 
capability to analyze pressure build up, lateral waste migration, 
vertical fluid permeation into overlying confining material, and 
leakage through defects in overlying aquitards; and models make it 
possible to predict tendencies or trends of events that have not yet 
occurred or that may not be directly observable. Under the no migration 
standard, a demonstration need not show exactly what will occur, but 
rather what conditions will not occur. Conservative modeling can be 
used to ``bound the problem'' and can legitimately form the basis for 
the petition demonstration. (See 50 FR 28126-28127 (July 26, 1988)).
2. Model Validation
    The conceptual model incorporated within the ``no-migration'' 
demonstration must be validated. The objective of model validation is 
to demonstrate that the model adequately represents the type of rock 
layers, the physical processes of the injection zone, and the boundary 
conditions of the modeled interval.
    In this case, a two-layer model was found to match the pressure 
responses measured during an interference test. We know from the 
measurements made during drilling that there are many layers of 
significantly different properties within the injection zone. However, 
it is often the case that the effects of many layers can be 
consolidated so that a simpler model can be used. The values determined 
for the two model layers are reasonable based on the type of rock in 
the injection zone and the actual measurements of physical properties. 
As a result, this part of the model is validated.
3. Verification of Mathematical Simulators
    When used to make predictions, the simulator must be adequately 
verified. The verification process has two principal objectives: (1) To 
ensure that the simulation code is mathematically accurate, and (2) to 
ensure that the various features of the code are used correctly. 
Frequently simulators are verified by comparing the results of the 
simulator to be verified against the results from a previously verified 
simulator or an analytical solution.
    Several different computer programs were used to simulate various 
phenomena in this demonstration. Pressurization was simulated using a 
computer code named INTERACT. The movement of the plume was simulated 
using empirical formulas which were verified by matching results of 
simulations incorporating similar models against those produced by 
SWIFT II, which has been extensively verified. Each of these methods 
and computer codes has been used in previous no migration 
demonstrations.

F. Application of Computer Simulation to the No-migration Demonstration

    The petitioner chose to demonstrate that waste injected at the EDS 
facility wastes will remain in the injection zone and will not migrate 
to a point of discharge or interface with an underground source of 
drinking water for a period of 10,000 years. This demonstration was 
based on a showing that a geological model representative of the 
disposal reservoir and the overlying rock strata would contain the 
waste constituents within the disposal reservoir for a period of 10,000 
years under the conditions of the simulation.
1. Model Development and Calibration
    The development of the EDS model was conceived to be conservative 
to account for the uncertainties which exist because of inherent 
geological variability and because the subject wells had not been 
constructed at the time the modeling was begun. A conceptual model was 
developed using information developed from logs, core and other testing 
carried out during drilling of the EDS 1-20 well. The model 
included hydrogeologic information such as porosity, permeability, and 
thickness of the various zones. Next, this initial set of hydrogeologic 
parameters was calibrated or fine-tuned by comparing pressure responses 
predicted using these parameters to pressure records from injection 
tests of wells 1-12 and

[[Page 77989]]

2-12 made during the period from June 12-15, 2002.
    Other model parameters, such as viscosity of the injected fluid, 
and diffusion coefficients of the waste constituents, were assigned 
from site-specific information when possible, and otherwise based on 
values which have been reported in similar situations and appeared in 
peer-reviewed writings. Where parameters were uncertain, conservative 
values were chosen. For those parameters most affecting pressure build 
up and waste migration, such as permeability, a range of values was 
modeled so that pressure and migration under less favorable conditions 
could be determined. This sensitivity analysis indicated that 
containment of wastes within the injection zone would occur even if 
actual conditions are much less favorable than there is reason to 
suspect.
    The original model assumed that flow within the injection zone 
would be within a single zone of uniform properties. This model failed 
to allow simulations of tests made in the 2-12 well to match 
pressures actually measured. EDS conducted an interference test by 
injecting water into one well and measuring the pressure in the other 
well to eliminate the pressure effects caused by residual blocking of 
pore throats in the sandstone reservoir adjacent to the well bores. 
Good data were obtained through this test, but the simulator could 
still not match the measured pressures. Other models were tried. A 
model incorporating layers having differing permeability with flow 
possible between the layers was found to result in a remarkably close 
match. The poorest match between correlative simulated and measured 
pressure values was within 1.5%. For the most part, the simulator was 
able to match the real data almost perfectly. The successful model 
includes one layer which is 33 feet thick with a permeability of 400 md 
and one which is 190 feet thick with a permeability of 63.43 md, as 
mentioned above in the Injection Zone Description. The porosity of both 
zones was set at 11%.
    This two-layer model is a reasonable explanation of how the 
disposal reservoir which was investigated during the drilling of the 
three EDS wells will react to injection. The logs and cores showed that 
there are many individual layers with varying permeability and that 
their effective net thickness is in the range of 200 to 250 feet. The 
average net porosity of these layers is about 11%. Other values used in 
the simulation also match those measured or calculated using standard 
procedures. As a result of approximating measurements made by tests in 
the wells, the model has been proved to be a valid surrogate for the 
reservoir itself. EDS actually modeled pressure buildup and plume 
movement only in the thinner zone (33 feet thick with 400 md 
permeability) to simplify the predictive modeling, This is conservative 
because it results in a more widespread plume and a larger radius for 
the zone of endangering influence than the use of the full two-layer 
model would. Although the results are less accurate than they might be, 
the deviation from accuracy is toward making the results appear to be 
``worse'' than we have reason to expect. Because we are less interested 
in accuracy than in ensuring we made conservative assumptions, such 
simplifications are an acceptable and commonly used practice.
2. Model Predictions
    Two simulation time periods were considered in the demonstration: A 
20-year operational period and a 10,000-year post-operational period. 
For the operational period, vertical migration was calculated as though 
the maximum allowable pressure was used for injection through the 
entire operational period. For the post-operational period, additional 
lateral migration due to the natural flow gradient and buoyancy, and 
additional vertical migration due to molecular diffusion were 
simulated. Modeling results, and the parameter choices which ensure 
that these results represent reasonably conservative conditions, are 
presented below.
    For the simulated operational period, the total simulated injection 
rate for the facility was set at 166 gpm for the first 19 years and 11 
months of the 20-year service life. For the final month, the simulated 
rate was increased to 270 gpm for a single well. This rate plan results 
in the highest possible pressurization of the reservoir. However, the 
33-foot reservoir layer accepted half of this volume while the 190 feet 
of the well bore with lower permeability accepted the remainder. This 
flow split was determined through the simulation. The product of the 
thickness and the average permeability of a zone relative to other 
available zones determines the fraction of flow which it will accept. 
The pressure increase in the 33-foot zone is the only result which was 
calculated. Assuming injection at the maximum rate into a portion of 
the injection zone provides a conservative cushion to the demonstration 
by causing an over-prediction of waste migration. To simplify 
computation and make the assumptions more conservative, the increase of 
1,176 psi, which was predicted to occur only at the end of the 
operational period as a result of increasing the injection rate to 270 
gpm, was assumed to exist for the length of the entire operational 
period. The maximum pressure buildup will be greatest near the 
injection wells and will decrease outward, declining to less than 89.6 
psi at a distance of 4.4 miles (the edge of the regulatory Area of 
Review) at the end of the 20-year operational period.
    Analytical solutions were also used to predict vertical waste 
migration. To be conservative, EDS doubled the length of the 
operational period, assumed that the maximum pressure will exist 
throughout this period, and found that injectate will penetrate through 
10.1 feet of the arresting strata.
    During the post-operational period, pressure in the injection zone 
will decrease and cease to cause movement. Molecular diffusion, which 
is random motion of individual molecules through the watery fluid which 
permeates even apparently dense rock, becomes the primary mechanism 
causing upward migration. EDS used an integrating method, taking into 
account lithologic differences for each foot of movement, to calculate 
vertical diffusion distance above the level reached by injectate during 
the operational period. This method also used the highest coefficient 
of molecular diffusion for any waste constituent and a concentration 
reduction to one trillionth (10 -12) of the starting 
concentration. This means that the resulting distance is that at which 
the concentration of any constituent will be less than one part in a 
trillion. For constituents which are still toxic at concentrations of 
one in a trillion, EPA will impose limits on starting concentrations in 
the injectate to ensure that no constituent will migrate beyond the 
resulting distance in hazardous concentrations. The EDS UIC permits 
will be modified to incorporate these limits. The maximum vertical 
movement of the waste front during the post-operational period is 227 
feet from the assumed starting point at 3,925 feet upward to 3,698 
feet, 239 feet below the top of the injection zone. This is a 
conservative estimate because it assumes 100% concentration of the most 
mobile constituent at the limit of pressure driven fluid movement for 
the entire post-operational period. Therefore, the waste will be 
contained within the vertical limits of the permitted injection zone 
throughout the post-operational period.
    Lateral migration of the waste plume during the operational period 
is driven almost exclusively by injection pressure. If 100% 
displacement of formation waters from a cylinder of rock

[[Page 77990]]

33 feet thick with an effective porosity of 11% is assumed, the plume 
edge would be 3,199 feet from a single well at the end of the 20-year 
simulation period. This distance is further increased as a result of 
failure to displace 100% of native formation waters from the cylinder 
surrounding the wells. The effect of this failure and diversion of 
waste from straightline movement as a result of diversion around sand 
grains is called dispersion. The effects of dispersion can be 
calculated. The preparers of the EDS demonstration used a reasonably 
conservative estimate of 300 feet for longitudinal dispersivity and 25% 
of that value, 75 feet, for transverse dispersivity. Dispersion will 
increase the distance of flow by 13,607 feet in direction opposite the 
Sun wells. Therefore, at the end of the projected 20-year operational 
period, the total distance from the center of the plume to the 
southwest edge of the plume determined at the 10-12 concentration ratio 
(initial concentration/final concentration) is 16,806 feet. As 
mentioned in the Area of Review Section, it is possible that Sun 
Pipeline will be injecting 2000 gpm for about two years during the life 
of the EDS well at its Inkster Terminal one half mile to the northeast 
of the EDS facility. This injection would cause the center of the plume 
to be displaced 2,870 feet to the southwest, 141 degrees west of north. 
This would drive the southwest edge of the plume 6,069 feet from the 
center of EDS' injection. Dispersion would increase this to 16,806 
feet. Therefore, the plume could extend more than three miles from the 
wells at the end of the projected 20-year operational period. This 
distance is within the area of review.
    The simulation of plume-flow distance and direction during the 
post-operational period considered buoyancy and the natural flow within 
the Mt. Simon and Eau Claire Formations added to the movement which 
occurs during the operation of the wells. Buoyancy flow occurs because 
the strata into which waste will be injected dip slightly northwest 
into the Michigan Basin and the specific gravity of the injected waste 
will be different than that of the native water now filling the pores 
in the injection zone. Buoyancy resulting from either lighter waste 
being injected into a more dense native brine or a denser waste being 
injected into a less dense natural formation water results in a 
substantial movement of the waste front. Because of the conservative 
assumptions concerning the specific gravity of the injected waste, the 
amount of movement due to the effects of buoyancy is conservative.
    The direction of buoyancy flow is 42 degrees west of north for a 
heavier waste and 166 degrees east of north for a lighter waste. EDS 
assumed that 100% of the waste to be injected will be a brine with a 
specific gravity of 1.22 (the heaviest fluid which might be injected) 
when calculating the distance of flow down into the Basin. When 
calculating the distance of movement up dip they assumed 100% of the 
waste will be methanol (the lightest fluid which might be injected) 
with a specific gravity of 0.88. Because the difference between the 
specific gravities of the native brine (1.153) and methanol is greater 
than the difference between those of a heavy waste, 1.22, and the 
native brine, the distance of movement due to buoyancy will be greater 
to the southeast. The angle of dip must also be considered. The dip to 
the southeast is 1.14 degrees and that to the northwest is about 0.68 
degrees. To be conservative, the greater angle of dip was used to 
calculate the distances in both directions. The distance of updip 
movement of the centroid of the plume possible as a result of buoyancy 
is 14,792 feet in a direction 166 degrees east of north if the entire 
plume is as light as methanol.
    Calculations based on the measurements made at the 2-12 
well and several others indicated that the rate of flow is 0.4 ft/year 
in a northeasterly direction. The effect of regional flow could result 
in an additional 4,000 feet of drift plus associated dispersion to the 
movement of the waste plume over 10,000 years. Because the direction of 
flow is actually somewhat uncertain, the 4,000 feet of possible 
movement due to regional flow was added to the total distance of the 
movement regardless of which direction it was calculated. The net updip 
movement of the plume centroid is 20,672 feet in a direction 172 
degrees east of north.
    From that point, an analytical method was used to account for 
dispersive spread and project plume movement to the health-based 
limits. To make this calculation, the distance the center of the plume 
is displaced by regional flow (4,000 feet), the distance the center of 
the plume is displaced by buoyancy (14,792 feet), and the distance the 
center of the plume might be displaced by the proposed Sun injection 
(2,870 feet), each acting alone, are added, for a total distance of 
21,662 feet. As explained earlier, the edge of the plume of hazardous 
waste is found where the concentration of waste constituents is reduced 
to one trillionth of the original concentration. Dispersion will move 
the health-based limit 27,539 feet beyond the end of the undispersed 
plume edge. At this distance, all hazardous constituents will be below 
the health-based levels or detection limits. To calculate the total 
distance of movement in the updip direction, the original radius of the 
plume (3,199 feet), the distances which the centroid is displaced by 
injection through other wells (2,870 feet), regional flow (4,000 feet), 
buoyancy (14,792 feet), and the distance added by dispersion must all 
be added, taking into account differences in the directions of the 
component vectors, including an additional 1,580 feet which SWIFT 
modeling indicates should be added to the results determined using the 
analytical method. Therefore, the maximum predicted lateral migration 
of waste at the EDS site is 52,990 feet (10 miles) in the updip, or 
southsoutheast, direction.
    EDS used similar methods to calculate the distance of movement in 
various directions away from the injection wells. The downdip plume 
edge was found to be within 36,158 feet or 6.85 miles of the injection 
center in a northwesterly direction. The nearest point of discharge 
into a USDW is hundreds of miles to the west. Figure 2 shows the 
distances beyond which we can be very certain that the waste will not 
spread through a period of 10,000 years. Therefore, EDS has 
demonstrated to a reasonable degree of certainty that hazardous 
constituents will not migrate vertically out of the injection zone nor 
laterally to a point of discharge in a 10,000 year period.

G. Quality Assurance and Quality Control

    EDS and its consultants have demonstrated that adequate quality 
assurance and quality control plans were followed in preparing the 
petition. EPA approved a quality assurance project plan on November 1, 
2001. Some changes were made to accommodate changes in plans. These 
were reviewed and given informal approval as necessary. EDS followed an 
appropriate protocol for locating records for penetrations in the AOR, 
for collection and analyses of geologic and hydrogeologic data, for 
waste characterization, and for all tasks associated with the modeling 
demonstration.

III. Conditions of Petition Approval

    In order to receive an exemption from the ban on injection of 
certain hazardous wastes, the EDS injection operation must meet the no-
migration standard and the operation must be

[[Page 77991]]

protective of human health and the environment. Federal regulations at 
40 CFR 146.13(a) establish the standard for a safe injection pressure. 
Region 5 has determined that operation at or below fracture closure 
pressure is the best means of assuring that the facility's injection 
pressure will be protective of human health and the environment. 
Therefore, as a condition of granting this exemption from the ban on 
injection of certain hazardous wastes, the EPA will impose following 
conditions:
    (1) The permitted injection zone must be comprised of the 
Precambrian, Mt. Simon and Eau Claire, Franconia-Dresbach, Trempealeau, 
and Glenwood Formations from 3,369 to 4,550 feet below the surface;
    (2) Injection shall occur only into that part of the Fraconia-
Dresbach, Eau Claire, Mt. Simon, and Precambrian Formations which is 
more than 3,900 feet below the surface and less than 4,550 feet, true 
vertical depths, below the surface;
    (3) The volume of wastes injected in any month through both wells 
at the site must not exceed 7,275,780 gallons. This volume will be 
calculated each month;
    (4) Maximum concentrations of chemical contaminants which are 
hazardous at less than one part in a trillion (1:1,000,000,000,000) 
shall have limits for maximum concentration at the well head set 
through the permits;
    (5) The injection pressure at the well head shall be limited to 
fracture opening pressure at the casing shoe. The fracture opening 
pressure while injecting waste of the highest density to be allowed was 
determined to be 903 psi (gauge) at the well head by tests constructed 
during drilling of well 2-12.
    (6) The petitioner shall fully comply with all requirements set 
forth in Underground Injection Control Permits MI-163-1W-C007 
and MI-163-1W-C008 issued by the EPA.
    (7) This exemption is only granted while the underlying assumptions 
are valid. For instance, if the injection rate at the SPL facility 
exceeds 2000 gpm averaged over a period of a year, EDS must run a new 
simulation to evaluate the effect.
    (8) The exemption will become invalid 20 years after injection 
commences. EDS must halt operations at that time unless Region 5 has 
approved a new, valid demonstration of no migration from the injection.
    There are currently no extraction wells within the AOR, and the 
demonstration does not consider the effects of any extraction, such as 
the extraction of fluid from the Mt. Simon proposed by the SPL in the 
permit application denied by MDEQ. If SPL drills and operates one or 
more extraction wells in the AOR, then the conditions under which the 
EPA determined the no-migration demonstration to be valid would no 
longer exist and the Director will terminate the exemption. EDS would 
be prohibited from injection of hazardous wastes and authorization to 
inject nonhazardous wastes would probably be withdrawn. EDS would be 
allowed to resume injection only if a new demonstration, demonstrating 
compliance with the standards of 40 CFR part 148, subpart C were 
approved.

    Dated: November 15, 2002.
Sally K. Swanson,
Director, Water Division, Region 5.

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