This comment letter response contains two parts:   

(1) The original submittal from the commenter.

(2) A data base printout of EPA’s response to each point raised by the commenter.

Notes about the response letters:

• The response letters were generated by a data base used to track the content of all public

comment submittals and ensure that the Agency responds to each. Each comment letter

was assigned a Letter ID that corresponds to the last four digits of the docket number of the

original comment (as posted on www.regulations.gov).

• Each response letter includes: comment text; an EPA‐assigned comment code; and an

individual response. These are described and explained below.  

• The data base contains Comment text from the letters submitted by commenters.  

Many hard copy letters were scanned into electronic format for inclusion in the data

base. As a result, there may be some typographical errors attributable to optical

character recognition issues.  However, all original submittals were reviewed in the

process of drafting responses to ensure that the comment content was understood and

appropriately addressed.

• The content of each comment letter was divided into topic areas and assigned a unique

Comment ID.  Additionally, one or more Comment Codes (i.e., unique topic area ID) was

assigned to each discrete point raised by a commenter. This information was added to

the data base. To inform final rulemaking decisions, all comments and information

received on a given topic were reviewed by technical experts in each rule area (e.g., on

construction requirements).  

• Following decisions on the final rule requirements, Individual responses were drafted

by topic area to ensure completeness and consistency of the responses with the final

rule and other responses to similar comments.  Each discrete point made by a

commenter was given a unique response.

• Upon completion of comment responses, all information was entered into the data base.

Each letter response is a compilation of each comment and its individual response,

compiled in the order of the original comment letter.  As a result of this process, there is

repetition in the response text.  The Agency believes this approach ensures completeness

and attention to each comment letter that was submitted.   

• All comments in a topic area were reviewed, evaluated, and responded to concurrently.  

Responses on each topic area are compiled and are also available in the rulemaking docket.
September 29,2009 

Water Docket 

Environmental Protection Agency 

Mailcode: 2822T 

1300 Pennsylvania Avenue NW 

Washington, DC 20460 

Re: Docket ID No. EPA-HQ-OW-2008-0390 

Electronically Delivered: Via: www.regulations.gov 

To Whom It May Concern: 

Company Introduction and Frame of Reference for Comments 

Global Energy, Inc. (Global) appreciates the opportunity to comment on the Notice of 

Data Availability (NODA) in the Subject Docket, as issued in 74FR44802, on August 31, 

2009, regarding Federal Requirements under the Underground Injection Control (UIC) 

Program for Carbon Dioxide (C02) Geologic Sequestration (GS) Wells. 

As we noted in our December 2008 comments on the Proposed Rule, Global is actively 

developing gasification based energy production projects, with particular focus on the 

production of Synthetic Natural Gas (SNG), Fischer-Tropsch (F-T) liquids, Hydrogen, as 

well as electric power generation via Integrated Gasification Combined Cycle (IGCC) 

technology. Gasification technology can effectively capture carbon dioxide (C02) during 

manufacture of energy products such as Synthetic Natural Gas (SNG) or 

Fischer-Tropsch liquid fuels. Gasification related technologies can also adjust the 

synthetic gas fuel composition (i.e. lower the carbon monoxide and increase the 

hydrogen content) to enable combustion emissions comparable or superior to natural 

gas. Importantly, Global is committed to carbon capture and sequestration (GGS), and 

believe it can be done cost effectively. As also noted in our earlier submittal, our Lima 

Energy project is planning Geologic Sequestration (GS) in the Mt. Simon Sandstone, 

which lies directly beneath western Ohio and several adjacent states. 

We appreciate the recent NODA and the opportunity to comment on it here. Global 

Energy appreciates the analysis and development work provided to USEPA by the 

National Laboratories, and EPA's willingness to "be adaptive" and incorporate beneficial 

results into the rule making. We encourage USEPA to proceed with the rule making, 

and feel it is important that the rule is structured in an adaptable manner in order to 

accommodate knowledge and experience over time. 

Global offers specific comments below, relative to different aspects of the NODA: 

Clob,ll [w}r9V inc Suite 2,10(\ 312 \'1"lnu[ S(r8el CiI1Ginnnti, Oil 4;)2(1) ty:;!\ 

reI5'\3·t)/1-0Uf! '" Ft{x' :1L'.;AI:;:?1,,;){Jllf 
2 

1. We concur that the NODA provides helpful and informative new information and 

that USEPA should proceed with finalizing the rule. 

2. We believe that "Far Field" pressure is important to understand, but need not be a 

concern with proper and effective injection site characterization, which in this case 

would consider pressure effects more remote from the injection site. A practical 

approach should be able to monitor plume pressure migration and alter the 

operation if appropriate. This is an area where more experience is needed and the 

rule should be written to foster gaining this experience. 

3. We do not support the view of other com menter's that more rigorous attention to 

RCRA and CERCLA are necessary or appropriate. The rule already prohibits 

injection of the regulated wastes, as well as injection stream characterization that 

will demonstrate that these characteristics are avoided. This is a C02 injection rule 

not a waste management rule. Regular update of the stream qualities is 

reasonable, without making the process overly burdened. 

As we noted in our earlier comments, if the requirements are too onerous GS of 

C02 will not occur as desired. 

4. We strongly support the proposed "adaptive approach" to this rule, and that USEPA 

should have flexibility to implement changes that result from experience gained 

over time. 

5. Our evaluations of the geology in Ohio and preliminary modeling of the Mt. Simon 

Sandstone ("the Mt. Simon") in the vicinity of Lima in Allen County, reinforces US 

Department of Energy knowledge of this deep saline aquifer, and their view that it is 

generally ideal of GS. One USDOE Regional Carbon Sequestration Partnership 

intended to utilize the Mt. Simon at a location less than forty miles from our project 

in Lima, Ohio. For reasons unrelated to the suitability of the site, the project is 

understood to be on hold. Our results are also supported by the Ohio Geologic 

Survey, whose periodic newsletter, attached here, addressed the subject in 2007. 

6. We support the requirement for project design with a "robust monitoring plan" that is 

capable of corroborating modeling with actual performance. This should include 

assessment of dissolution or dissociation and effects on the mobilization of trace 

elements. 

7. We note that a LBNL study, referenced in the NODA, made an assumption in a 

release scenario that "leakage into a shallow aquifer would occur at a constant rate 

over a 100 year period". Constant rate leakage is not logical, especially over such 

a long time period -7 pressures (driving force) will decline, and mineralization will 

occur, to list two factors against constant rate leakage. The assumption is not even 

valid as a "worst case scenario". 
3 

8. While the LBNL work is appreciated, USEPA should view it as a "generalization" 

and still allow "local studies in local conditions". Specifically, assessment of 

leakage risk needs to be in context of local conditions. 

9. We appreciate the modeling LBNL conducted of a hypothetical sedimentary basin 

with several projects injecting high aggregate and cumulative quantities of C02 

annually over an extended period. The results, though hypothetical, argue in favor 

of case-specific consideration of: (a) large volume injections; and (b) defendable 

close proximity between injection points. That is local conditions may 

accommodate higher than normal injection rates and closer proximity to other 

injection activity. 

Specifically, the rule should be finalized with language that allows consideration of 

injection projects that, based on modeling, that show the injection horizon to have 

characteristics favorable to high-volume injection and/or relatively close proximity 

injection sites. Injection pressure effects, plume migration rate, and avoidance of 

fracture pressure would be some of the considerations. 

10. As noted earlier, we support consideration of the potential effects of "far field" 

pressure build up in siting criteria to ensure the integrity of the injection horizon 

remote from the injection location. The rule should allow case specific 

determination of appropriate injection quantities and conditions. 

11. The rule should provide for data collection and reporting to facilitate EPA 

knowledge accumulation and its "adaptive" rule management. 

12. We support USDW protection, and argue for a practical rule and implementation to 

facilitate actual deployment of GS (Le. the process needs to be practical or it will 

not evolve timely). 

13. We strongly concur with the observation that "treating high-salinity" waters (i.e. 

those in excess of USDW protectiveness threshold) will be generally less costly 

than obtaining water rights. 

14. We support the view of some States that GS should be allowed where site-specific 

demonstration is made that USDW will be protected ~ even though depth criteria 

may not be in conformity with the basic rule requirement for injection below the 

lower most aquifer. A straightforward "waiver" process may serve in these cases. 

There should NOT be a blanket prohibition of injection above or between USDWs. 

Well completion technology and characterization of injection horizon and fluid 

interaction is a sufficiently developed state of the art to promote EPA's "adaptive 

rule making". 

Global [!~erpv Inc. Suits ?:lOO :11~' V\I,1Inlll Slm"L C !IlGiIHlati OH ,1 :';20;' US1\ 

Tel' ;)1:,; (l~'1,nO(1 <> Fa):, b 1 J b./l S~l4/ 
4 

15. We strongly support the EPA view that different well classes warrant different 

treatment, and that EPA approval criteria should therefore differ. C02 at injection 

pressures will greatly differ from other fluids regardless of well class. In EPA's 

phrase, "site-suitability" for GS is what needs to be determined. 

16. For pragmatic reasons, with respect to deployment of GS at least, State Discretion 

and Delegation should be maximized; as well as the cooperative relationships with 

external expertise, whether State or not, that USEPA has already established. 

Again, we appreciate the opportunity to provide these comments and look forward to 

well-founded regulations that provide a pragmatic, cost effective and expeditious path 

forward in the management of carbon dioxide via the utilization of Class VI wells. 

Respectfully Submitted, 

Dwight N. Lockwood, PE, QEP 

Group Vice President 

P: 

Email: 

513.621.0077 

dnlockwood@globalenergyinc.com 

Attachment: Ohio Geologic Survey Quarterly Newsletter, 2007 Issue 2 

Ci(,i)dl [nuIUY inc. SUits ::'300 W<llnul Sti e~)l C:ni~lI1n()!1 Of 145:0:02, USA 

TC'I 'in U:'1UU!f • f Sl:Hi!15'Qi 
Geologic sequestration of carbon 

dioxide in Ohio 

By Larry Wickstrom 

Much research on carbon dioxide sequestration is taking place worldwide, yet many people 

do not understand what sequestration is and 

why so much effort is going into researching it. 

Carbon dioxide (C02) naturally occurs in the 

air we breathe and within the earth's crust. We 

also use it in fire extinguishers and dry ice and 

as the source of bubbles in soda pop. So, why 

are we trying to get rid of such a common and 

useful gas? 

Carbon dioxide is one of many gases known 

to cause an elevated warming of the earth 

through the greenhouse effect. Known greenhouse gases (GHGs) include carbon dioxide, 

methane, nitrous oxides, and hydrofluorocarbons. Carbon dioxide comprises nearly 80% 

of the GHGs emitted into the atmosphere by 

humans. Many people feel that human contributions of GHGs into the atmosphere may be 

having a significant impact on global climate 

change. Thus, research is taking place on ways 

to reduce the amount of GHGs that society emits 

into the atmosphere. 

Infrared radiation is emitted from the earth's surface. Some 

passes through the atmosphere and some is absorbed and 

re-emitted in all directions by greenhouse gas molecules, 

which warms the earth. 

Greenhouse gases in 

the earth's atmosphere 

trap some solar 

radiation. 

warm the earth. 

The United States emits more CO2 than any 

other country in the world. Total world anthropogenic (human-made) CO2 emissions for 2002 

are estimated to have been 24.405 million metric tons. In 2005, the U.S. Energy Information 

Administration reported that the United States 

emitted 5,746 million metric tons of carbon 

dioxide. During the same year, Western Europe 

was the second-largest producer of CO2 emissions at 3,585 million metric tons, and China 

was the third-largest producer at 3,176 million 

metric tons (it is projected that China will emit 

more CO2 than the United States within the next 

several years). Within the United States, Ohio 

is the fourth-largest producer of CO2 emissions 

behind California, Texas, and Pennsylvania, 

respectively. 

It is estimated that in 2003, Ohio emitted 

265.5 million metric tons of CO2 into the atmosphere. This amount is distributed between 

electric power generation, transportation, industry, and commercial and residential output. 

The primary sources of anthropogenic CO2 are 

activities that involve burning hydrocarbons. 

Other activities, such as the manufacture of iron 

and steel. cement, and fertilizers, also contribute 

significantly to Ohio's carbon footprint (a carbon 

footprint is the total amount of carbon dioxide 

directly or indirectly caused by a specific activity. entity, or product life cycle). The two largest 

sources of Ohio's CO2 from hydrocarbons are 

electric power generation and transportation. 

Nearly 90% of Ohio's electricity comes from 

coal-burning power plants, and coal-burning 

power plants are the single largest emitter of CO2 

in Ohio. 

To be sustainable in the long-term, our 

SOciety must develop more fuel-efficient vehicles 

and, ultimately, an alternative energy source for 

transportation. For near-term planning, large 

industrial point-sources of CO2, such as coalburning power plants, provide the best and most 

cost-efficient opportunity to capture and sequester CO2 before it is emitted into the atmosphere. 

continued on page 3 
2 • ohio Geology • 2007, No.2 ....................................................... 

0

, ." "'N-'" " .... : -. I '1'-'0' ,~ :. . '. .' :a'-'- ~ '0' I " . "C'- I .'. . ~K'-~"'I' \ '. '. ,,: , \ , .. ....... ' ... ";' ~ ,'\,,.;,' ,_ . ~ ........ " ... I' ... _ ", . ~' ........ ' ... " ~ _. .~ ~ ... I. ."," ~' " . ,,' '+ 

Larry Wickstrom, 

Division Chief and State Geologist 

Recently, stakeholders in many natural 

resources issues have placed much emphasis 

on the term sustainable development, which was 

defined by the 1987 Brundtland Commission 

as "meeting the needs of the present without 

compromising the ability of future generations 

to meet their own needs." I think the popularity 

of this concept is long past due and I hope the 

momentum of sustainable development continues in its wise application. 

The Division of Geological Survey investigates many aspects of Ohio's geology that are 

relevant to sustainable development in the state. 

Geology is the ground we live on; the rocks and 

minerals we use to produce building materials and energy; the geologic hazards (such as 

landslides and earthquakes) that threaten us; and 

so much more. How our society uses natural resources and interacts with our geology (building 

roads or shopping malls, for example) affects the 

sustainability of such developments. By striving 

for sustainable development, we are recognizing 

that we cannot control what nature gives us any 

more than we can control earth processes like 

erosion or the rising and falling of water levels. 

We can only control how we use our natural resources for short- and long-term development. 

Each of us uses a large amount of energy 

and mineral resources every day. To meet our 

own demands, we must operate sand, gravel, 

and limestone quarries; mines; and oil and gas 

wells. To obtain sustainable development, we 

must practice conservation methods on an 

individual and national level. The United 

States, and Ohio in particular, have 

some of the highest environmental 

standards and regulations in the 

world. When we deny development 

of extractive industries locally, we 

are often transferring the burden 

of producing the commodities 

that we use to somebody who will 

develop the resources using environmental standards that are lower 

than our own. By displacing this 

responsibility, we make environmental 

problems worse and increase commodity prices for ourselves, especially when 

the commodities have to be transported from 

remote locations to our own localities. 

The Five pIs-Proper Planning Prevents 

Poor Performance. We've all heard this saying 

before, but, until recently, few of our communities actually took into account their natural 

resources management when planning for development (even though communities are built 

and maintained using natural resources). Here's 

a scenario that has happened over and over 

again across the nation: A local zoning commission allows developers to build wherever they 

want; for example, next to an existing quarry. In 

this situation, rock material from the quarry is 

used to build houses and roads in the development, and then the quarry cannot be expanded 

because of the dense housing development 

around it. Soon, all of the "neighbors" complain about the dust and noise from the quarry 

and start efforts to shut it down. Inevitably, the 

quarry operator is portrayed as the source of 

the problem when in reality the lack of planning from developers and community leaders 

began the problem. This is just one example of 

how our society needs to take control of our 

development in a sustainable manner. Thankfully, some local and regional commissions are 

now conSidering our natural resources when 

planning. It is short-sighted to develop over our 

best sand and gravel deposits and our access to 

the best groundwater just as it is short-sighted 

to build in landslide prone areas. 

The work products of the Ohio Geological 

Survey are an integral part of long-range planning for sustainable development, which helps 

prevent future conflicts, shortages, and myriad 

other problems. Our mapping shows where the 

best sand and gravel, aggregate, and coal deposits exist and helps identify and delineate lake 

coastal erosion and other geohazards, as well as 

groundwater resources. 

While on the topic of sustainable development, readers should know that the Division of 

Geological Survey has been very involved for 

several years in characterizing the geology of 

the state for geologic sequestration of carbon 

dioxide, which is released during many natural 

and human-caused processes, such as when coal 

is burned for electric power generation. The lead 

article in this month's Ohio Geology attempts 

to explain a little more about carbon dioxide 

sequestration and how it affects our state. 

www.ohiodnr.com/geosurvey/ 
· ..................................................... . Ohio Geology • 2007, No.2· 3 

continued from page 1 

Methane Nitrous 

9.5% oxide 

5.8% 

Percentage breakdown of greenhouse gases (excluding 

water vapor) that humans emit into the atmosphere. 

(Data source: < http://www.climatetechnology.gov » 

What is CO2 Sequestration? 

Carbon dioxide sequestration, simply put, 

is capturing and securely storing carbon dioxide from the atmosphere and/or human-made 

sources before it is released into the upper atmosphere. There is a natural carbon cycle in which 

earth processes consume carbon (e.g., photosynthesis; weathering of silicate rocks) as well as 

produce carbon dioxide (e.g., volcanoes; oxidation of plant life). Most of the C02 released into 

the atmosphere is from these natural processes. 

Anthropogenic CO2 emissions account for only 

3 to 4 % of the world's carbon output, but many 

scientists feel that this amount is enough to 

cause global climate change. 

We can use natural processes to sequester 

C02 from the atmosphere and mitigate anthropogenic CO2. Through agriculture, development, 

mining, and other activities, humans have removed a significant amount of carbon from our 

soil systems. Terrestrial sequestration methods 

such as no-till farming seek to replenish this lost 

carbon by capturing carbon from the atmosphere via photosynthesis and locking it into 

the soil. However, there is a limit to how much 

carbon the soil can hold, so terrestrial sequestration cannot mitigate the effects of all anthropogenic CO2. 

Geological sequestration involves injecting 

C02 into appropriate rock units in the deep subsurface (generally greater than 2,500 feet deep) 

where it is securely stored, or trapped. Once it is 

trapped in the subsurface, it will slowly combine with the native fluids found in the rocks 

and react with the minerals and organic matter 

in the geologic formation to form (precipitate) 

stable compounds/minerals, primarily calcium, 

iron, and magnesium carbonates. Mapping of 

geologic sequestration capacities by the Division 

of Geological Survey and other resource professionals has shown hundreds of years of storage 

capability in Ohio. The wide-scale deployment 

of geologic and terrestrial sequestration technologies appears to be key in facilitating sustained 

and significant reductions in CO2 emissions. 

The primary attraction of geologic sequestration for public planners and resource professionals is the potential for direct and long-term storage of C02 emissions in close proximity to large 

CO2 sources (such as ethanol or power plants). 

However, to achieve this objective, the potential 

capacity of any geologic reservoir needs to be 

verified by detailed regional assessments, as well 

as site-specific investigations to allow decisionsmakers to fully understand the characteristics of 

the geologic sequestration system. The Division 

of Geological Survey has been working on both 

regional and site-specific projects over the past 

seven years. 

Natural geologic reservoirs have held oil, 

natural gas, water, and even CO2 for millions of 

years with minimal to no leakage. These same 

systems are thought to offer both near-term 

opportunities and longer-term possibilities 

for future management of anthropogenic CO2. 

Some industries use these natural reservoirs 

for storage of industrial wastes (hazardous and 

industrial waste injection wells) and the disposal 

of oilfield brines (brine injection wells). Natural 

gas is also stored in geologic reservoirs for later 

withdrawal during peak (winter) usage periods to 

lessen the demand on the interstate pipeline system. Additionally, the injection of C02 in oil field 

reservoirs to stimulate additional oil production 

(enhanced oil recovery [EOR)) has been taking 

place since the early 1 970s and is a growing 

methodology in the petroleum industry. Thus, 

substantial experience with geologic injection 

operations already exists. 

mt = million tons 

Ohio's anthropogenic C02 emissions by sector (2003). 

(Data source: U.S. Energy Information Agency) 

www.ohiodnr.com/geosurvey/ 
4 • Ohio Geology • 2007, No.2 ....................................................... 

What are Ohio's primary potential 

geologic reservoirs for CO2? 

There are several types of geologic reservoir 

systems that are being investigated for potential 

CO2 sequestration. In Ohio, two types have the 

largest near-term capacity for storage and use. 

These are deep saline formations and oil and 

gas fields. 

Deep saline formations are natural saltwaterbearing intervals of porous and permeable rocks 

that occur beneath the level of potable groundwater. Currently, a number of saline formations 

in Ohio are used for waste-fluid disposal; thus, a 

long history of technological and regulatory factors exists that could be applied to CO2 injectionl 

storage. Saline formations are widespread, close 

to many large CO2 sources, and are thought to 

have large pore volumes available for potential injection. In order to maintain the injected 

CO2 in liquid form, the injection zone must be 

approximately 2,500 feet or greater in depth. 

Impervious confining rock 

C02 displaces methane 

from deep unmineable 

coal seams 

Impervious confining rock 

CO2 displaces trapped 

oil and gas 

Impervious confining rock 

Depleted oil and gas 

reservoirs store CO2 

Impervious confining rock 

Deep saline reservoirs 

store C02 

Maintaining the C02 in a liquid phase is desirable because it can more readily mix and go into 

solution with a native formation's brine and, as a 

liquid, it takes up less volume than when it is in 

gaseous form. One ton of CO2 at surface temperature and pressure (in its gaseous phase) occupies almost 18,000 cubic feet. The same amount 

of C02 injected to a depth of approximately 

2,500 feet will occupy only 50 cubic feet. The 

2,500-foot minimum sequestration depth also 

helps insure that there is an adequate interval 

of rocks (confining layers) above tFte potential 

injection zones to serve as a geologic seal. 

In these types of reservoirs, C02 is injected 

under pressure down a specially constructed 

wen into the reservoir where it displaces and 

mixes with saline water and fins the pore spaces 

between the mineral grains of the rocks in the 

reservoir. The CO2 is trapped within the rock 

matrix. Depth, permeability, injectivity, reservoir 

pressure, reservoir integrity, and water chemistry 

are some of the variables that control the sequesGeneralized block diagram illustrating CO2 from an industrial source being injected in deep 

saline formations for storage and 

for use in enhanced oil recovery 

(EOR). 

Sand and gravel 

Limestone 

www.ohiodnr.com/geo5urvey/ 
· ..................................................... . Ohio Geology • 2007, No.2' 5 

tration potential of deep saline formations. In 

addition to the properties of the injection zone or 

reservoir, characterization of the overlying seal 

units (confining layers) is necessary. The injected 

CO2 has a lower specific gravity than natural 

formation fluids, thus it is more buoyant and will 

rise to the top of the porous zones. Cap rock units 

must be relatively impermeable and sufficiently 

thick to arrest any appreciable vertical movement of the CO2 within the sequestration interval, 

thereby trapping it in the deep subsurface. 

Oil and gas fields represent geologic traps 

(structural or stratigraphic) that contain hydrocarbons within a reservoir with a known cap or 

seal. In depleted or abandoned petroleum fields, 

CO2 sequestration would take place by injecting 

CO2 into the reservoir to fill the pore volume left 

by the extraction of oil or natural gas resources. 

The injected C02 would be trapped by the same 

limits as the original hydrocarbon for secure 

storage in the reservoir. Volume, permeability, 

injectivity, pressure, reservoir integrity. water 

chemistry. the nature of the cap rock or reservoir seal, and the history of production are some 

of the variables that control the sequestration 

potential of depleted oil and gas fields. This may 

be an attractive sequestration option in some 

parts of Ohio because large areas of the state 

have a long history of oil and gas recovery (to 

view an Ohio oil and gas fields map online, go to 

< www.ohiodnr.com/Portals/1 O/pdf/pgO 1. pdf> . 

However, much caution must be exercised when 

investigating this potential because of the large 

number of old, undocumented wells abandoned 

within some areas of the state. These wells could 

provide pathways for the CO2 to leak upward. 

In active oil fields, it has been demonstrated 

in other parts of the country that CO2 can be 

used for enhanced oil recovery (EOR). In this 

process, some of the oil that remains in reservoirs after primary production is recovered by 

injecting CO2 that 1) repressurizes the reservoir 

and displaces and drives the remaining oil to a 

recovery well, and 2) directly mixes and chemically interacts with the remaining oil to make 

it more mobile, allowing more oil to be pushed 

to the producing wells (miscible flooding). Approximately 70 oil fields worldwide (most of 

these in the western US) currently inject C02 for 

EOR, and over 1 billion barrels of additional oil 

have been produced, which demonstrates the 

effectiveness of this value-added sequestration 

option. The Division of Geological Survey maintains the oil and gas field maps of Ohio and performs research to characterize the reservoirs for 

more efficient production of oil and gas and for 

possible use of them as CO2 containers. The Division of Geological Survey is currently attempting 

to form partnerships and the funding necessary 

to investigate the effectiveness of using specific 

Ohio reservoirs for C02 EOR. 

A third type of geologic reservoir, deep, unmineable coal beds. may have (limited) potential 

for storing CO2 in Ohio. Carbon dioxide injected 

into unmineable coal beds would not only occupy 

pore space but bond, or adsorb, onto the carbon 

in the coal. Because of this adsorption. miscibility would not be a concern like in oil and gas 

reservoirs and saline formations, and C02 injection (and resulting enhanced recovery of coalbed 

methane) could occur at shallower depths than in 

depleted oil reservoirs or saline formations. 

Coal beds often contain large amounts of 

methane within the pore space of the coal as 

well as adsorbed onto the coal itself. The adsorption rate for CO2 in coals is approximately twice 

that of methane; thus. injected CO2 displaces 

methane and allows for potentially enhanced 

gas recovery while sequestering CO2. 

Is Ohio well suited for geologic 

CO2 sequestration? 

The Division of Geological Survey has been 

analyzing data from tens of thousands of wells 

and producing dozens of maps of favorable Ohio 

sequestration reservoirs and cap rocks as part of 

a multi-state partnership, the Midwest Regional 

Carbon Sequestration Partnership (MRCSP). 

Some of the resultant maps and data can be 

viewed as an interactive map available on the 

Division's website < www.dnr.state.oh.us/ 

website/geosurvey/MRCSPGEO/disclaimer.htm> ; 

you may also want to visit the MRCSP website 

< www.mrcsp.org> for more information about 

the partnership and CO2 sequestration in general. The Division of Geological Survey will soon 

release a publication about the regional mapping and capacities estimate for the state and the 

Midwest region. 

The partnership's initial assessments of 

Ohio's deep C02 storage capacity indicate that 

Ohio can potentially sequester approximately 

45 billion tons of CO2• This represents about 350 

years of Ohio's current output of CO2 from stationary point sources. However. that capacity is 

not equally distributed around the state-some 

geologic areas have high storage potential while 

other areas have little to no potential. This is 

very important information to help the public 

and large CO2-producing industries plan for 

future CO2 sequestration sites and/or pipelines 

that distribute CO2 from point-source iocations 

to appropriate storage sites. 

www.ohiodnr.com/geosurvey/ 
6 • Ohio Geology • 2007, No.2 

Drill rig on location at the Ohio 

Geological Survey C02 No. I carbon 

sequestration research well in Tuscarawas County, Ohio. 

1/ ...... /" • 

Revised karst map 

available 

....................................................... 

In addition, we still have much to learn about the rate at which reservoirs will 

accept C02 and how pressure buildup from neighboring injection operations might 

interact with one another. This information is vital in determining how many wells 

would be needed and the spacing intervals between them, which determine the 

level of compression needed, pipeline lengths, and the overall distribution of operations. Therefore, the Division of Geological Survey continues to develop more 

detailed data, maps, and models related to CO2 sequestration. Working with the 

Ohio Air Quality Development Authority, Battelle Memorial Institute, and the U.S. 

Department of Energy, we recently completed drilling a deep test well < www. 

ohiodnr.com/Home/ogcim/ogcim/C02/tabid/17870IDefault.aspx > in Tuscarawas 

County. We are now performing detailed analyses on its rock materials and data 

and will issue a report on this important project in early 2008. We also continue to 

gather and analyze data from existing and new deep wells. 

Through geologic sequestration research, the Division of Geological Survey 

has gained close partnerships with dozens of companies and trade associations, 

including the U.S. Department of Energy, Battelle Memorial Institute, the Ohio 

Coal Development Office, the Ohio State University, Western Michigan University, 

the Interstate Oil and Gas Compact Commission (IOGCC), and the state geological surveys of Indiana, Illinois, Kansas, Kentucky, Maryland, Michigan, Pennsylvania, and West Virginia. Through these efforts and partnerships, the Division of 

Geological Survey has assumed a regional leadership role in carbon sequestration 

and is nationally recognized for this role. The knowledge gained and the contacts 

maintained through this work have helped prepare Ohio for future greenhouse gas 

registries and regulations and for companies that plan to build clean fuel and power 

plants in our state. 

Further Reading 

The Brundtland Commission, 1987, Our Common Future: Oxford, Oxford University Press, 

400 p. The full text of the Brundtland Report, hosted by the Swiss Federal Office for Spatial 

Development ARE, can be downloaded as a scanned copy of the UN General Assembly 

document A1421427-a 16 MB pdf file at < http://www.are.admin.ch/themen/nachhaltig/ 

00266100540100542Iindex.html?lang = en > . 

''Z > 'i 

• The 2007 release of Known and ProQabl~ .... 

Karst in Ohio, originally released in.1999 and 

revised in 2002, includes new /drift thickness'.{~ .. 

and karst data-including 57 newly documented 

sinkhole/s andcaves~giving map ,users a more 

comprehensive product to use when identifying karsfareas. The map depicts areas of kndwn 

and probable karst terrain, where dissolution 

processesin carbonate rocks (limestQne ,and . 

dolomite) and gypsum have pr()dw;:e4;.net,Works. 

of<;onduits below the ~lJrfctCe and siflkholesand') 

caves at the surfaqe. Environm.ental anqsoCietal'\t 

concerns 'related to karst inc~t.1de groundwater: .' 

contam.ination and unlfxpectedcbnstruction 

costs and delays. . . 

Known and Probable KarsUn Ohio can be' 

purchased from theOhio Geological;~urv:y for' 

. S15. Please see ordering information on page 8. > 

WWW~.9hi9dnr .• com/ge(;su.r.veYI • 
· ..................................................... . Ohio Geology • 2007, No.2· 1 

Book review of Roadside Geology of Ohio 

Roadside Geology oj Ohio is University of Toledo Geology Professor Dr. Mark 

Camp's second book in Mountain Press's 

Roadside Geology series. The series' 

six-by-nine-inch paperback format and 

vision-friendly text and graphics make the 

book easy to use while traveling. Instead 

of chapters in a book or a map in an atlas, 

this book features 25 driving routes, such as 

"1-71: Columbus to Cincinnati." Each route 

has an overview map, usually with several 

geologic or historic features labeled on it, 

and a few pages describing the geology along the 

route. Camp expands on his book's introductory 

review of geology by including a discussion on 

the geology, bedrock formations, and Ice Age deposits and features in four Ohio regions. He also 

describes significant geologic and historic events 

specific to each region. 

In addition to the route maps and text, there 

are numerous sidebar features on points of 

geologic, historic, and economic interest that are 

either quickly accessible or visible from many of 

the routes. This well-illustrated book has numerous historic and present-day black and white 

photographs highlighting Ohio's geology and 

how it played a role in the state's development. 

The book also includes a glossary, a list of additional reading material, and a thorough index. 

This book will be a valuable asset to anyone 

living in or visiting Ohio who wants to make 

traveling through the state both entertaining and 

educational. 

-Doug Shrake 

Roadside Geology oj Ohio can be purchased 

from the Ohio Geological Survey for $24. Please 

see ordering information on page 8. 

Revised Ohio earthquake map available 

Earthquake Epicenters in Ohio and Adjacent Areas was originally developed in 2002 

to document the magnitude and spatial 

distribution of earthquakes with epicenters 

in Ohio and surrounding areas. More than 

30 earthquakes in the Ohio region have occurred since 2002 and are included on the 

new 2007 map, which allows map users 

to easily gain information about the most 

recent earthquakes, as well as earthquakes 

dating back to 1776: earthquake event time, 

location, depth, magnitude, felt-area size 

and information source. This dataset allows 

users to determine which portions of the 

state are historically more susceptible to 

earthquakes and to apply this knowledge to 

varied applications, including earthquake 

insurance rate determinations, construction 

strength determinations for bridges and buildings, and research on deep-earth structures such as 

hidden faults. 

The new map shows a concentration of earthquake epicenters in two areas of the state: 

western Ohio in the vicinity of Shelby County, and along the Lake Erie coast in Lake County at 

Painesville. While it might seem like earthquakes are occurring more frequently in recent years, 

the Ohio Seismic Network attributes this perceived change to improved technology and communication among people who experience the earthquakes. 

Earthquake Epicenters in Ohio and Adjacent Areas can be purchased from the Ohio Geological 

Survey for S 1 O. Please see ordering information on page 8. 

www.ohiodnr.com/geo5urvey/ 
8 • Ohio Geology • 2007, No.2 ....................................................... 

Survey staff changes 

Comings: 

• Mike P. Angle-Geology Program Supervisor, 

Geologic Mapping and Industrial Minerals 

Group 

• Christopher P. Gordon (promoted)-Geologist 

2, Energy Resources Group 

• Katy H. Pan-Publications Editor, Technology 

Transfer Group 

Goings: 

• Paul M. Harbulak-Geographic Information 

Management Systems Specialist 2, Lake 

Erie Geology Group 

• Christiana A. Tickle-Publications Editor, 

Technology Transfer Group 

Ordering information 

To order any of the Survey's publications 

or maps, contact the Geologic Records Center, 

2045 Morse Road, Bldg. C-l, Columbus, Ohio 

43229-6693; telephone: 614-265-6576; fax: 

614-447-1918; email: geo.survey@dnr.state. 

oh.us. In-state sales tax rates are based upon 

the county where the map is shipped. Handling 

charges apply to all mailed orders (please call for 

rates). Visa and MasterCard are accepted . 

Re ... release Of popular 

local geology book 

With help from their supporters, including the Ohio Geological Survey, the Kentucky 

Geological Survey recently released the second 

edition of University of Cincinnati (UC) Geology 

Professor Emeritus Paul E. Potter's Exploring 

the Geology oj the Cincinnati/Northern Kentucky 

Region. Potter's 128-page report-style paperback 

is popular with amateur and professional geologists, historians, teachers, and planners because 

it carefully balances technical information about 

the area with many illustrations, sidebars, and 

interesting photographs. Potter says about half 

of the 87 illustrations in the book have been updated for the new version. The text also reflects 

new information about subsurface geology and 

how it affects people at the surface. 

Sections of the book are dedicated to today's 

geological issues, such as land movements, how 

geology affects groundwater levels, and use of 

geographic information systems (GIS). However, 

the immediate and local relevance of geology is 

present throughout the history sections of the 

book as well. 

Potter's publication is unique in that it focuses on a primarily urban area. It is timely because 

it reflects the significant population growth of 

the Cincinnati area in recent years. When the 

book was first released in 1996, the area's population was 1.7 million. Today it is 2 million. 

Exploring the Geology oj the CincinnatilNorth~ 

ern Kentucky Region can be purchased from 

the Ohio Geological Survey for $15. Please see 

ordering information at left. 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

Ted Strickland, Governor 

Sean 0 Logan, Director 

Larry Wickstrom, State Geologist & Chief 

OhiO Department of Natural Resources 

DiViSion of Geological Survey 

2045 Morse Road, Bldg C-1 

Columbus, OhiO 43229-6693 

614-265-6576 

geo survey@dnrstate all us 

www ohlodnr com/geosurvey/ 

OhiO Geology IS a free publication To become a 

subscnber please contact the DIVISion of Geological 

Slirvey at tile above address, phone number, or email 

Back Issues can be found on the DIVISIOn'S webSite 

Compilers Mac SWinford, Greg Schumacher, 

and Mark Wolfe 

Editor Katy Pan 

Layout!Deslgn Lisa Van Doren 

An Equal Opportunity Employer-M/F/H 

Pnnted on recycled paper 

PRSRTSTD 

U.S. Postage 

PAID 

Columbus, OH 

Permit No. 5767 

Administration/State Geo\o9lst GeoJo9ic Mapping and Energy Resourcfui Group Lake Erfe Geology Group Techoolo9yTransfer Group Geologic Records Center 

614·265·6988 In~"strial Minerals Group 614,265·6602 614·~65·6597 419·626·4296 614·265·6591 614·~65·6576 Or 614·265·6585 
Letter ID: 0332  

Commenter: Dwight N. Lockwood  

Organization: Global Energy, Inc.  

Letter ID: 0332 Comment ID: 28187 Letter Lines: 53 to 64  

Comment Code: 1000 1. General Comments on the Notice of Data Availability  

Comment: We appreciate the recent NODA and the opportunity to comment on it here. Global  

Energy appreciates the analysis and development work provided to USEPA by the  

National Laboratories, and EPA’s willingness to "be adaptive" and incorporate  

beneficial results into the rule making. We encourage USEPA to proceed with the  

rule making, and feel it is important that the rule is structured in an  

adaptable manner in order to accommodate knowledge and experience over time.  

Global offers specific comments below, relative to different aspects of the  

NODA:  

1. We concur that the NODA provides helpful and informative new information and  

that USEPA should proceed with finalizing the rule.  

Individual Response: EPA is finalizing the rule and intends to follow an adaptive approach to the GS

rulemaking to incorporate new research, data, and information about GS. For more information on the

adaptive approach, see the responses to comments on the proposed rule in the rulemaking docket.  

Letter ID: 0332 Comment ID: 28188 Letter Lines: 66 to 71  

Comment Code: 2220 2.2.2. Basin‐Scale Hydrologic Impacts of CO2 Storage (seeking comment)  

Comment: 2. We believe that "Far Field" pressure is important to understand, but need not  

be a concern with proper and effective injection site characterization, which in  

this case would consider pressure effects more remote from the injection site. A  

practical approach should be able to monitor plume pressure migration and alter  

the operation if appropriate. This is an area where more experience is needed  

and the rule should be written to foster gaining this experience.  

Individual Response: EPA agrees that proper site characterization, together with predictive modeling

and far‐field pressure monitoring are important components of siting and managing GS projects. The
final GS rule requires a detailed site‐specific evaluation of local geologic conditions (§146.82) and

modeling to delineate the AoR based on the detailed geologic data collected during the site

characterization process (§146.84). Monitoring of the plume and the pressure front are required

throughout the operational phase (§146.90). One goal of the siting and AoR delineation process is to

identify the potential for pressure changes that may cause unacceptable fluid movement, even if they

occur far from the injection well. If such pressure increases were predicted at levels that could

potentially endanger USDWs, a GS site would not be permitted. If far field pressures were to increase

above predicted levels, pressure management schemes via brine extraction from the storage reservoir

may be an appropriate remedial action; however prevention of such impacts is the focus of the GS rule.

For additional information regarding EPA’s requirements for AoR delineation and monitoring for GS

projects, see the responses to comments on the proposed rule in the rulemaking docket.  

Letter ID: 0332 Comment ID: 28189 Letter Lines: 73 to 81  

Comment Code: 1100 1.1 Comments on the Comprehensive Approach  

Comment: 3. We do not support the view of other commenter’s that more rigorous attention  

to RCRA and CERCLA are necessary or appropriate. The rule already prohibits  

injection of the regulated wastes, as well as injection stream characterization  

that will demonstrate that these characteristics are avoided. This is a CO2  

injection rule not a waste management rule. Regular update of the stream  

qualities is reasonable, without making the process overly burdened.  

As we noted in our earlier comments, if the requirements are too onerous GS of  

CO2 will not occur as desired.  

Individual Response: EPA acknowledges that GS falls within the broader context of CCS and the need for

regulatory clarity to ensure that USDWs are protected from endangerment. In developing the final GS

rule, the Office of Water coordinated with other Agency program offices and across federal agencies

(e.g., with the Department of Energy; United States Geological Survey; Bureau of Ocean Energy

Management, Regulation, and Enforcement, formerly the Minerals Management Service; Bureau of

Land Management). The Agency continues to evaluate areas of potential applicability of other Federal

environmental statutes including, but not limited to: the Clean Air Act; the Resource Conservation and

Recovery Act; the Comprehensive Environmental Response, Compensation, and Liability Act; and the

Marine Protection, Research and Sanctuaries Act to various aspects of GS and CCS. The Agency will

continue to coordinate on GS and CCS related issues to minimize redundancy and maximize efficiencies

for owners or operators. For additional information, please see the discussion entitled "How Does This

Rulemaking Relate to Other Federal Authorities and GS and CCS Activities?" in the preamble to the final

GS rule.  
Regarding RCRA, the final GS rule requires owners or operators to characterize their CO2 stream as part

of their permit application process to determine whether the injectate is a RCRA hazardous waste. If the

CO2 stream is determined to be a hazardous waste, injection may only occur in a Class I hazardous

waste injection well. Additionally, EPA clarifies that a determination as to whether the presence of

hazardous substances in CO2 results in CERCLA liability from a sequestration facility depends entirely on

the composition of the specific CO2 stream and the environmental media in which it is stored (e.g., soil

or ground water). For additional information, see the preamble to the final rule and the responses to

comments on the proposed GS rule.  

Letter ID: 0332 Comment ID: 28190 Letter Lines: 83 to 85  

Comment Code: 1000 1. General Comments on the Notice of Data Availability  

Comment: 4. We strongly support the proposed "adaptive approach" to this rule, and that  

USEPA should have flexibility to implement changes that result from experience  

gained over time.  

Individual Response: EPA is finalizing the rule and intends to follow an adaptive approach to the GS

rulemaking to incorporate new research, data, and information about GS. For more information on the

adaptive approach, see the responses to comments on the proposed rule in the rulemaking docket.  

Letter ID: 0332 Comment ID: 28192 Letter Lines: 97 to 100  

Comment Code: 2120 2.1.2. SWP (Aneth Field, UT)  

Comment Code: 5450 5.9. Comments on the Proposed Monitoring Requirements (146.90)  

Comment: 6. We support the requirement for project design with a "robust monitoring plan"  

that is capable of corroborating modeling with actual performance. This should  

include assessment of dissolution or dissociation and effects on the  

mobilization of trace elements.  

Individual Response: EPA agrees that GS project design requires a robust monitoring plan. An essential

part of that monitoring plan must be obtaining data to validate computational model performance. The

GS rule includes requirements at 146.90(d) for ground water monitoring for geochemical changes, which

can be used to detect mobilization of metals and dissolution of CO2 in subsurface brine. See the

response to comments document for the proposed rule for additional information on EPA’s final

approach to monitoring for GS projects.  
Letter ID: 0332 Comment ID: 28193 Letter Lines: 102 to 112  

Comment Code: 2210 2.2.1. Groundwater Quality and Mobilization of Trace Elements (seeking

comment)  

Comment: 7. We note that a LBNL study, referenced in the NODA, made an assumption in a  

release scenario that "leakage into a shallow aquifer would occur at a constant  

rate over a 100 year period". Constant rate leakage is not logical, especially  

over such a long time period ‐> pressures (driving force) will decline, and  

mineralization will occur, to list two factors against constant rate leakage.  

The assumption is not even valid as a "worst case scenario".  

8. While the LBNL work is appreciated, USEPA should view it as a  

"generalization" and still allow "local studies in local conditions".  

Specifically, assessment of leakage risk needs to be in context of local  

conditions.  

Individual Response: EPA agrees that the LBNL study is a generalization with the objective to better

understand, in a global sense, the vulnerability of representative and relevant aquifer types in the case

of CO2 intrusion, in order to provide sound scientific information as a basis for further studies on

groundwater quality concerns. The study was not meant to be site specific; rather the authors suggest

the work should be followed by site‐specific investigations, such as in situ experiments with associated

modeling. Furthermore, the LBNL study focused on the potential consequences of CO2 leakage into

USDWs, without assessment of the probability for leakage. It is understood (and mentioned in the

NODA) that the risk of CO2 leaking from deep storage is low for properly managed GS projects.

However, the potential conse¬quences of unlikely leakage events need to be understood and predictive

capabilities need to be developed as a basis for risk and vulnerability assessment.  

As to the leakage case chosen for the LBNL modeling study, EPA notes that even a comprehensive

sensitivity study cannot encompass all possible aquifer conditions and release scenarios. The 100‐year

time period selected in the LBNL study is reasonable, assuming that the leak remains undetected. The

time period was chosen to be able to evaluate both the short‐term and the long‐term geochemical

consequences of leakage.  

EPA agrees over‐pressures necessary to inject CO2 into a storage reservoir will decline following

cessation of injection, which may reduce the risk of leakage in certain cases. However, buoyancy forces

causing upward migration of CO2 through geologic formations will remain for hundreds if not thousands

of years following injection, long after over‐pressures due to injection have dissipated in the injection

zone. Furthermore, sequestration of CO2 by the aqueous phase and by precipitation of carbonates is

very slow in relation to the 100‐year time period specified. Finally, the specified leakage rate is very

small compared to the expected volume of CO2 in geologic storage reservoirs, i.e., only about 2.4 tonnes

CO2/yr.  
EPA clarifies that site‐specific data are necessary to understand the potential geochemical reactions at a

GS site. For this reason, all GS project owner or operators must submit detailed, site‐specific information

about a proposed GS site, including information on the porosity, permeability, mineralogy, and

geochemistry of the targeted injection and confining zones as well as all USDWs within the Area of

Review. Operators must also present information on the compatibility of the CO2 stream with fluids in

the injection zone and minerals in the injection and confining zones (§146.82(c)(3)). The data can help

the Director determine the potential for geochemical reactions between the injectate (CO2) and the

host geologic formations. For additional information on EPA’s approach to site characterization for Class

VI GS wells, see the responses to comments on the proposed rule in the rulemaking docket.  

Letter ID: 0332 Comment ID: 28194 Letter Lines: 114 to 132  

Comment Code: 2220 2.2.2. Basin‐Scale Hydrologic Impacts of CO2 Storage (seeking comment)  

Comment: 9. We appreciate the modeling LBNL conducted of a hypothetical sedimentary basin  

with several projects injecting high aggregate and cumulative quantities of CO2  

annually over an extended period. The results, though hypothetical, argue in  

favor of case‐specific consideration of: (a) large volume injections; and (b)  

defendable close proximity between injection points. That is local conditions  

may accommodate higher than normal injection rates and closer proximity to other  

injection activity.  

Specifically, the rule should be finalized with language that allows  

consideration of injection projects that, based on modeling, that show the  

injection horizon to have characteristics favorable to high‐volume injection  

and/or relatively close proximity injection sites. Injection pressure effects,  

plume migration rate, and avoidance of fracture pressure would be some of the  

considerations.  

10. As noted earlier, we support consideration of the potential effects of "far  

field" pressure build up in siting criteria to ensure the integrity of the  

injection horizon remote from the injection location. The rule should allow case  

specific determination of appropriate injection quantities and conditions.  

Individual Response: The LBNL modeling study of the hypothetical basin was not meant to provide

arguments in favor of large‐volume projects and close proximity between sites. Rather, LBNL started

with the assumption that in order to have GS make a contribution to climate change mitigation, large

volumes of CO2 may have to be injected and individual projects may have to be in proximity to each

other. The example study cited assumes that one third of the current annual emissions from large
stationary sources in the hypothetical sedimentary basin are being captured and stored.

EPA agrees with the commenter that the determination of appropriate injection quantities and

conditions is important, and the GS rule requires that the AoR delineation account for the types of site‐

specific circumstances the commenter describes. The rule requires that the owners or operators of GS

wells delineate the AoR for GS sites using computational fluid flow models appropriate to the site‐

specific conditions and injection regime (§146.84). These site‐specific conditions include the injectivity

and storage capacity to allow the appropriate volume of injection for the particular formation without

initiating or propagating fractures in the confining zone(s) and creating risk to any ground water

resources due to any effects of hydraulic perturbations. For additional information regarding EPA’s

requirements for AoR delineation for GS projects, see the responses to comments on the proposed rule

in the rulemaking docket.  

Letter ID: 0332 Comment ID: 28195 Letter Lines: 134 to 139  

Comment Code: 5700 5.14. Comments on Other Aspects of the Proposed Rule  

Comment: 11. The rule should provide for data collection and reporting to facilitate EPA  

knowledge accumulation and its "adaptive" rule management.  

12. We support USDW protection, and argue for a practical rule and  

implementation to facilitate actual deployment of GS (i.e. the process needs to  

be practical or it will not evolve timely).  

Individual Response: The final rule is based on the most recent GS‐related data, information, and

scientific research available. EPA intends to continue to collect data on GS and to incorporate such data

as it implements its adaptive approach to GS rulemaking. EPA plans to, every six years, collect and

review data on GS projects to determine whether the appropriate amount and types of information and

appropriate documentation are being collected, and to determine if modifications to the requirements

are appropriate or necessary.  

For additional information on the adaptive approach and site specific requirements, see the responses

to comments on the proposed rule in the rulemaking docket.  

Letter ID: 0332 Comment ID: 28196 Letter Lines: 141 to 143  

Comment Code: 3000 3. Injection Depth for GS Projects  

Comment: 13. We strongly concur with the observation that "treating high‐salinity" waters  
(i.e. those in excess of USDW protectiveness threshold) will be generally less  

costly than obtaining water rights.  

Individual Response: EPA acknowledges the concerns regarding water availability and interest in current

and future water resources and recognizes that advances in technology are making high TDS aquifers

more attractive as potential future water sources. EPA clarifies that the primary purpose of the GS rule is

the protection of USDWs from endangerment and the purpose of the permitting, siting, construction,

operation, monitoring, post‐injection site care, financial responsibility, and site closure requirements for

Class VI injection wells is to further this goal.  

Letter ID: 0332 Comment ID: 28197 Letter Lines: 145 to 154  

Comment Code: 3210 3.2.1. Comments Generally in Support of the Approach  

Comment: 14. We support the view of some States that GS should be allowed where site‐  

specific demonstration is made that USDW will be protected ‐> even though depth  

criteria may not be in conformity with the basic rule requirement for injection  

below the lower most aquifer. A straightforward "waiver" process may serve in  

these cases. There should NOT be a blanket prohibition of injection above or  

between USDWs.  

Well completion technology and characterization of injection horizon and fluid  

interaction is a sufficiently developed state of the art to promote EPA’s  

"adaptive rule making."  

Individual Response: EPA acknowledges the commenter's support of the waiver approach and site‐

specific flexibility in regulatory development and permitting as described in the NODA and Request for

Comment. The Agency acknowledges that there are some situations where injection into non‐USDW

formations above the lowermost USDW can be performed in a manner that protects USDWs.  

EPA agrees that a flexible, site‐specific approach to waiver determinations (and all Class VI permitting

decisions) is appropriate. Site‐specific demonstrations of injection zone integrity along with proper well

construction, operation, monitoring, and post closure site care are the best way to ensure USDW safety

while allowing flexibility for GS above or between USDWs. EPA believes that the additional requirements

that apply to owners or operators of Class VI wells granted a waiver of the injection depth requirements

will provide additional considerations for the owner or operator and Director when permitting such

wells to ensure protection of all USDWs. EPA adds that all determinations regarding the appropriateness

of a waiver will be made by the Director based on site‐specific information. Additionally, the final GS rule

does not categorically preclude or prohibit injection into any type of formation.
The Agency believes this approach: 1) responds to concerns about local and regional geologic storage

capacity limitations imposed by the proposed injection depth requirements; 2) allows for a more site‐

specific assessment of injection depth for GS projects; 3) accommodates injection into different

formation types; 4) allows for injection of CO2 for GS into non‐USDWs above and/or between USDWs

when appropriate and where it can be demonstrated that USDWs will be protected; and 5) responds to

concerns about the use of aquifer exemptions for GS. Finally, EPA's approach to addressing injection

depth variability through a waiver process responds to concerns about future drinking water resource

availability and the need to ensure that high quality water remains available in sufficient quantities to

supply drinking water needs.  

Letter ID: 0332 Comment ID: 28198 Letter Lines: 156 to 160  

Comment Code: 3100 3.1. Comments on Concerns About Injection Depth for Class VI Wells  

Comment: 15. We strongly support the EPA view that different well classes warrant  

different treatment, and that EPA approval criteria should therefore differ. CO2  

at injection pressures will greatly differ from other fluids regardless of well  

class. In EPA’s phrase, "site‐suitability" for GS is what needs to be  

determined.  

Individual Response: EPA agrees that site and project specific factors are important in determining the

applicability of GS in a specific formation. The final GS rule includes flexibility for the Director to consider

site‐specific geology and proposed operational conditions when making permitting decisions. EPA

believes that proper siting, well construction, operation, monitoring, and post‐injection site care are key

to determining site suitability for GS and ensuring USDW protection from endangerment.  

Letter ID: 0332 Comment ID: 28199 Letter Lines: 162 to 165  

Comment Code: 3390 3.3.9. Comments Regarding State Discretion to Adopt the Waiver Approach  

Comment: 16. For pragmatic reasons, with respect to deployment of GS at least, State  

Discretion and Delegation should be maximized; as well as the cooperative  

relationships with external expertise, whether State or not, that USEPA has  

already established.  

Individual Response: EPA clarifies that adoption of the waiver process remains at the discretion of

individual UIC programs. Therefore, States, Territories, and Tribes seeking primacy for Class VI wells are

not required to provide for injection depth waivers in their UIC regulations and may choose not to make

this process available to Class VI wells under their jurisdiction. Although some commenters asked EPA to
require that waivers be applied nationally, the Agency believes that the decision about whether a waiver

program is appropriate in a specific State, Tribe, or Territory should be made by each program. This

approach allows flexibility for individual program Directors to determine the appropriateness of allowing

for waivers based on regional or state‐specific conditions, such as the predominant geologic settings

anticipated to be used for GS or other land uses in the state while ensuring maximum protection of

USDWs. The final approach for injection depth waivers represents minimum Federal requirements. UIC

program Directors may adopt GS requirements that do not allow injection above or between USDWs if

they determine this to be appropriate (for conditions in their State, Territory, Tribe, or Region) and

protective.