### 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.

### California State Water Resources Control Board (SWRCB) Comments to:

Federal Requirements under the Underground Injection Control (UIC)

Program for Carbon Dioxide (CO 2 

### ) Geologic Sequestration (GS) Wells;

Notice of Data Availability and Request for Comment

SWRCB Comment #1 on : “ 2. Basin-Scale Hydrologic Impact of CO 2 

### Storage”

The Lawrence Berkeley National Labor atory (LBNL) modeled an area, 570

kilometers (km) by 550 km, with 20 carbon dioxide (CO 2 

### ) injection points at 5

million tons of CO 2 

### per year, total 100 mln. tons per year. (Humans breathing

about 6-million tons of CO 2 

### /day, which equates to over 2-billion tons/year). To

store human CO 2 

### alone would require over 20 these areas. The LBNL simulation

indicated that the subsurface pressure change induced by injection extends over

area of 400 km 2 

### after 50 years. Model’s a ssumption was that there was an

extensive confining la yer over the entire CO 2 

### sequestration area. A specific code

was used for simulation was developed for m odeling of water or solute migration

in porous media, not for subs urface gas migration.

Findings:

• Confining layer(s) for fluids (w ater or oil) may not confine CO 2 

### -type gases.

• CO 2 

### dissolved in water creates carbonic acid. Carbonic acid is corrosive

to several types of rocks which wi ll dissolve rock. This will increase

porosity by enlarging existing rock frac tures, which creates a conduit for

CO 2 

### gases to escape from the repositor y formation into the atmosphere.

• Injection of CO 2 

### into exhausted oil and natur al gas bearing formations will

have high potential for CO 2 

### to migrate back to the atmosphere.

Additionally, the formation has been perforated by thousands of oil and

natural gas wells (abandoned or not) allowing CO 2 

### to escape to the

atmosphere.

• Future tectonic events (earthquakes) will likely cause catastrophic release

of CO 2 

### into drinking or potentially drinking water aquifers and the

atmosphere.

B. SWRCB Comment #2 on : “IV. Injection De pth for GS Projects A. What

did EPA propose for Class VI well injectio n depth relative to the location of

USDWs?”

• Injecting CO 2 

### above or below the water supply aquifer is irrelevant since

under extreme pressure and high temperature, CO 2 

### gas will migrate

downward and upward, following poros ity, fault zones or man-made

pathways. Plus, you cannot compare CO 2 

### gas to liquid injection since CO 2 

### gas will expand under pressure in all directions, and has much greater

mobility than fluids. Gas will penetra te rock with much smaller opening

### pores or fractures than those needed for fluid migration. Fluid

compressibility and subsequent expansibility is negligible compared to this

of gases. The LBNL modeling show ed injected gas will expand for

hundreds of miles, for many years after injection stops, and sooner or later

may reach area(s) where will be able to e scape to the surface or drinking

water aquifer.

• CO 2 

### is heavier than air and if release to the surface at high concentration

will be deadly.

• Example:

o In 1986, a tremendous explosion of CO 2 

### from the lake Nyos, West

of Cameroon, killed more than 1700 people and livestock up to 25

km away. The dissolved CO 2 

### is seeping from springs beneath the

lake and is trapped in deep water by the high hydrostatic pressure.

If the CO 2 

### saturation level is reached, bubbles appear and draw a

rich mixture of gas and water up. An avalanche process is triggered

which results in an explosive ov er-turn of the whole lake.

• CO 2 

### injection (to save earth from an uncertain climate changes) may result

in water supply contamination (EPA declared CO 2 

### as a pollutant that need

to be regulated) or even catastrophic re lease that can kill thousands.

• After 20 years of investigation and b illions dollars spent at Yucca Mountain

repository, the US EPA and some scientists cannot warrant that that

Yucca Mt repository is totally safe. After thousands of years radioactive

elements may leak from the reposito ry and in another thousands of years

may reach drinking ground water at concentration exceeding maximum

contaminant level. The reported CO 2 

### modeling by LBNL cited in this

document is limited to 100- years period.

• What fraction of CO 2 

### generated world-wide (30 b illion tons/year) can be

injected into selected formations in t he USA and at what cost? How this

fraction of stored CO 2 

### will affect earth atmosphere and subsequently

temperature on earth?

C. SWRCB Comment #3 on : “D. - Evaluation of concerns about injection

depth for Class VI wells”:

• Laterally continuous, impermeable conf ining units on large scale have not

been found to exist in nature.

• Laterally continuous, CO 2 

### injection zones with the required porosity and

chemistry are very rare in nature.

• Continuous zone free of fractures and faults have not been found to exist

in nature.

### • Characterization of fractures and f aults deep under ground is not currently

possible; the proposed Yucca M ountain waste repository site

characterization process includes access to deep zone through miles of

tunnels and boreholes. Even with all of this, there are still uncertainties

about its safety.

D. SWRCB Closing Comments:

• There are hundreds of thous ands of undocumented, abandoned

wells and boreholes across US t hat are either not mapped or

identified. These wells and boreholes are a conduit for CO 2 

### to

either escape to the atmosphere or to adjacent drinking water

aquifers. To identify, map and proper ly destroy theses “artificial

penetrations” before CO 2 

### injection can take place is such a great

task it borders on the impossible.

• No waiver should be issued in any area that has extensive

groundwater use, high density wate r or oil wells, seismically

unstable now or potentially in t he future, potential for earthquakes,

volcanic activities presently or in distant future.

• Injecting such a small fraction of CO 2 

### is high risk and its cost to

benefit-effect on climate change is negligible. Also, the State of

California does not allow for permits to dispose of hazardous

materials through injection wells.Letter ID: 0339

Commenter: John Borkovich

Organization: California State Water Resources Control Board (SWRCB)

Letter ID: 0339 Comment ID: 28009 Letter Lines: 22 to 50

Comment Code: 2220 2.2.2. Basin

‐ Scale Hydrologic Impacts of CO2 Storage (seeking comment)

Comment: SWRCB Comment #1 on: "2. Basin

‐ Scale Hydrologic Impact of CO2 Storage"

The Lawrence Berkeley National Laboratory (LBNL) modeled an area, 570 kilometers

(km) by 550 km, with 20 carbon dioxide (CO2) injection points at 5 million tons

of CO2 per year, total 100 mln. tons per year. (Humans breathing about 6

‐

million tons of CO2/day, which equates to over 2

‐ billion tons/year). To store

human CO2 alone would require over 20 these areas. The LBNL simulation

indicated that the subsurface pressure change induced by injection extends over

area of 400 km2 after 50 years. Model's assumption was that there was an

extensive confining layer over the entire CO2 sequestration area. A specific

code was used for simulation was developed for modeling of water or solute

migration in porous media, not for subsurface gas migration.

Findings:

Confining layer(s) for fluids (water or oil) may not confine CO2

‐ type gases.

CO2 dissolved in water creates carbonic acid. Carbonic acid is corrosive to

several types of rocks which will dissolve rock. This will increase porosity by

enlarging existing rock fractures, which creates a conduit for CO2 gases to

escape from the repository formation into the atmosphere.

Injection of CO2 into exhausted oil and natural gas bearing formations will have

high potential for CO2 to migrate back to the atmosphere. Additionally, the

formation has been perforated by thousands of oil and natural gas wells

(abandoned or not) allowing CO2 to escape to the atmosphere.

Future tectonic events (earthquakes) will likely cause catastrophic release of

CO2 into drinking or potentially drinking water aquifers and the atmosphere.

Individual Response: In response to the commenter’s criticism of the specific code used in the study,EPA clarifies that the TOUGH2 model used is a general purpose simulation program designed for multi

‐

dimensional fluid and heat flows of multiphase and multi

‐ component fluid mixtures in porous and

fractured media. TOUGH2/ECO2N simulates water and solute transport together with gas migration of

supercritical CO2.

EPA agrees that the factors cited by the commenter are important considerations. The GS rule requires

geologic site characterization to verify the presence of adequate confining layers, help predict

geochemical reactions which can lead to dissolution and/or precipitation of minerals, and identify the

presence of seismic sources and faults or fractures to address these concerns (§146.82).

EPA acknowledges that induced seismicity is a risk that may be associated with GS but maintains that

the risk is low (IPCC, 2005). The GS rule contains several requirements to address seismic risk. First, as

part of the site characterization process, owners or operators must submit information about the

seismic history of and seismic sources near a proposed GS site, data on known or suspected faults in the

AoR, geomechanical information on fractures, stress, ductility, rock strength, and in situ fluid pressures

within the confining zone (§146.82(a)(3)). Owners or operators must also conduct extensive monitoring

to detect possible CO2 movement from the injection zone (§146.90). For additional information

regarding EPA’s requirements for AoR delineation and monitoring of GS projects, see the responses to

comments on the proposed rule in the rulemaking docket.

Letter ID: 0339 Comment ID: 28010 Letter Lines: 52 to 68

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

Comment Code: 3220 3.2.2. Comments in Opposition to the Approach

Comment: B. SWRCB Comment #2 on: "IV. Injection Depth for GS Projects A. What did EPA

propose for Class VI well injection depth relative to the location of USDWs?"

Injecting CO2 above or below the water supply aquifer is irrelevant since under

extreme pressure and high temperature, CO2 gas will migrate downward and upward,

following porosity, fault zones or man

‐ made pathways. Plus, you cannot compare

CO2 gas to liquid injection since CO2 gas will expand under pressure in all

directions, and has much greater mobility than fluids. Gas will penetrate rock

with much smaller opening pores or fractures than those needed for fluid

migration. Fluid compressibility and subsequent expansibility is negligible

compared to this of gases. The LBNL modeling showed injected gas will expand for

hundreds of miles, for many years after injection stops, and sooner or later may

reach area(s) where will be able to escape to the surface or drinking water

aquifer.CO2 is heavier than air and if release to the surface at high concentration will

be deadly.

Individual Response: EPA believes proper siting, well construction, operation, monitoring, and post

‐

injection site care will allow CO2 to be sequestered, despite its buoyancy. The GS rule is designed to

ensure that appropriate requirements are in place to protect USDWs from endangerment. EPA

acknowledges that faults and artificial penetrations offer paths for fluid movement. For this reason, the

GS rule contains requirements at §146.82 for characterization of faults and fractures, and §146.84

requires an AoR evaluation and corrective action. For additional information on characterization of

faults and fractures, AoR, and corrective actions, see the preamble to the final rule and the responses to

comments on the proposed GS rule.

In addition, owners or operators seeking waivers from the injection depth requirements must provide

additional information about the injection zone; identification of confining units above and below the

injection zone; and tailored AoR modeling above and below the injection zone, as required at

§146.95(a).

Letter ID: 0339 Comment ID: 28011 Letter Lines: 94 to 109

Comment Code: 3310 3.3.1. Site Characterization

Comment: C. SWRCB Comment #3 on: "D.

‐ Evaluation of concerns about injection depth for

Class VI wells":

Laterally continuous, impermeable confining units on large scale have not been

found to exist in nature.

Laterally continuous, CO2 injection zones with the required porosity and

chemistry are very rare in nature.

Continuous zone free of fractures and faults have not been found to exist in

nature.

Characterization of fractures and faults deep under ground is not currently

possible; the proposed Yucca Mountain waste repository site characterization

process includes access to deep zone through miles of tunnels and boreholes.

Even with all of this, there are still uncertainties about its safety.

Individual Response: EPA disagrees that laterally continuous, impermeable confining zones and laterally

continuous injection zones are rare in nature. Existing geologic structures such as gas and oil fields andnatural CO2 domes have shown the ability to trap and retain gases for millions of years. Many owners or

operators of injection projects have made similar demonstrations to satisfy UIC permitting requirements

(e.g., Class I through V), including evaluating the existence of laterally continuous injection and confining

zones and the absence of transmissive faults and fractures. For additional information on site

characterization for GS projects, see the preamble to the final rule and the responses to comments on

the proposed GS rule.

Letter ID: 0339 Comment ID: 28012 Letter Lines: 111 to 118

Comment Code: 5000 5. Comments on the Proposed Rule (out of NODA Scope)

Comment: D. SWRCB Closing Comments:

There are hundreds of thousands of undocumented, abandoned wells and boreholes

across US that are either not mapped or identified. These wells and boreholes

are a conduit for CO2 to either escape to the atmosphere or to adjacent drinking

water aquifers. To identify, map and properly destroy theses "artificial

penetrations" before CO2 injection can take place is such a great task it

borders on the impossible.

Individual Response: This comment pertains to EPA’s proposed GS rule (73 FR 43492) and is outside the

scope of the Notice of Data Availability. Please see responses to comments on the proposed rule for

EPA’s response to similar comments.

Letter ID: 0339 Comment ID: 28396 Letter Lines: 70 to 92

Comment Code: 6000 6. Other Comments that are Out of Scope for the NODA

Comment: Example:

In 1986, a tremendous explosion of CO2 from the lake Nyos, West of Cameroon,

killed more than 1700 people and livestock up to 25 km away. The dissolved CO2

is seeping from springs beneath the lake and is trapped in deep water by the

high hydrostatic pressure. If the CO2 saturation level is reached, bubbles

appear and draw a rich mixture of gas and water up. An avalanche process is

triggered which results in an explosive over

‐ turn of the whole lake.

CO2 injection (to save earth from an uncertain climate changes) may result inwater supply contamination (EPA declared CO2 as a pollutant that need to be

regulated) or even catastrophic release that can kill thousands.

After 20 years of investigation and billions dollars spent at Yucca Mountain

repository, the US EPA and some scientists cannot warrant that that Yucca Mt

repository is totally safe. After thousands of years radioactive elements may

leak from the repository and in another thousands of years may reach drinking

ground water at concentration exceeding maximum contaminant level. The reported

CO2 modeling by LBNL cited in this document is limited to 100

‐ years period.

What fraction of CO2 generated world

‐ wide (30 billion tons/year) can be injected

into selected formations in the USA and at what cost? How this fraction of

stored CO2 will affect earth atmosphere and subsequently temperature on earth?

Individual Response: This comment is outside the scope of the Notice of Data Availability and the UIC

Program’s authority under the GS rulemaking.

Letter ID: 0339 Comment ID: 28579

Comment: Individual Response:

Letter ID: 0339 Comment ID: 29236 Letter Lines: 120 to 127

Comment Code: 3220 3.2.2. Comments in Opposition to the Approach

Comment: No waiver should be issued in any area that has extensive groundwater use, high

density water or oil wells, seismically unstable now or potentially in the

future, potential for earthquakes, volcanic activities presently or in distant

future.

Injecting such a small fraction of CO2 is high risk and its cost to benefit

‐

effect on climate change is negligible. Also, the State of California does not

allow for permits to dispose of hazardous materials through injection wells.

Individual Response: EPA acknowledges the commenter's concerns about USDW protection and clarifies

that the mission of the UIC Program is to protect USDWs from endangerment. Based on an evaluation of

comments on the proposed injection depth requirements and the waiver process discussed in theNODA, and concerns about USDW protection, EPA believes that there are limited situations where

injection into non

‐ USDW formations above the lowermost USDW can be performed in a manner that

protects USDWs. The final GS rule at §146.95 establishes a process by which owners or operators can

seek a waiver of the Class VI injection depth requirements. The waiver approach establishes

requirements for extensive site

‐ specific information related to injecting above or between USDWs

(including ground water use and water supply needs, as the commenter suggests) that the owner or

operator must submit and the Director must consider, in consultation with PWSS Directors, to ensure

that water supplies in the area and all USDWs are protected.

EPA clarifies that any decision to grant a waiver (or a Class VI permit) will be based on extensive study of

the proposed area, including the number and condition of wells in the air and seismic history.