^^^\TEO STAr^

^L 9R0TE

^

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY


WASHINGTON, D.C. 20460

OFFICE OF


AIR AND RADIATION 

The Honorable James M. Inhofe 

United States Senate 

Washington, D.C. 20510 

Dear Senator Inhofe: 

Thank you for your letter of February 4, 2013, co-signed by four of your colleagues, expressing 

concerns with the U.S. Environmental Protection Agency's forthcoming proposed regulations for motor 

vehicle emissions and gasoline standards known as the "Tier 3" standards. 

The EPA is developing proposed Tier 3 standards to improve air quality by reducing harmful pollutants 

emitted from motor vehicles, and to create a harmonized national vehicle emissions control program. 

Similar to the Tier 2 standards referred to in your letter, we expect the proposed Tier 3 standards to be 

based on a "systems approach" that includes proposed vehicle emission standards as well as proposed 

reductions in gasoline sulfur content. Considering the vehicle and its fuel as an integrated system 

enables technologically feasible and cost-effective emission reductions beyond what would be possible 

looking at vehicle and fuel standards in isolation. 

At the time the Tier 2 standards were developed, there was not sufficient data on vehicle operation and 

emission performance with gasoline sulfur levels below 30 ppm. Since that time, it has been 

demonstrated that catalyst efficiency would be significantly improved with even lower sulfur levels, 

including for Tier 2 vehicles. The Tier 3 gasoline sulfur standards that we are considering proposing 

would require sulfur levels similar to that already being achieved in California, Europe, Japan, SQuth 

Korea, and several other countries. Lower sulfur gasoline will lead directly to emission reductions and is 

necessary to operate the pollution control equipment to achieve new Tier 3 vehicle standards. 

The EPA understands the importance of potential cost impacts on refineries, and that is why we will 

include extensive refinery-by-refinery analyses of the costs associated with the proposed Tier 3 gasoline 

sulfur control program in the proposed rulemaking, and solicit comment. We estimate the cost of the 

forthcoming proposed standards to be on average about a penny per gallon. Our evaluation of gasoline 

sulfur control costs has undergone independent peer review and is corroborated by two independent 

studies (by Mathpro Inc. and Navigant Economics). The Baker & O'Brien study cited in your letter, 

which estimates a slightly higher average cost increase of 2.1 cents per gallon, is based on a number of 

problematic assumptions that bias the study towards overstatement of costs, including but not limited to 

a very stringent cap on gasoline sulfur content and a lack of programmatic flexibilities the EPA plans to 

propose.

Internet Address (URL) • http://www.epa.gov


Recycled/Recyclable • Printed with Vegetable OIl Based Inks on Recycled Paper (MInimum 50% Postconsumer content)
The proposed Tier 3 program we are considering would address significant public health issues that 

exist currently and are projected to continue in the future. The data and analysis detailing the need for 

and benefits of the proposed Tier 3 standards will be documented in the forthcoming notice of proposed 

rulemaking. By reducing motor vehicle emissions, the proposed standards would lead to improvements 

in ambient concentrations of harmful pollutants such as ozone and particulate matter (PM). Health 

benefits associated with reductions in ozone and PM are well-established, and the proposed Tier 3 

program would lead to reductions in adverse health impacts such as respiratory symptoms in children, 

exacerbation of asthma and premature mortality. Further, implementation of the proposed Tier 3 

program would assist areas with attainment dates in 2018 and beyond in attaining and maintaining the 

National Ambient Air Quality Standards for ozone and may relieve areas from some of the burden 

associated with adopting additional local controls. 

It's important to emphasize that this would be a proposal, subject to stakeholder and public input 

through the notice and comment process. We agree that major rules such as Tier 3 require robust and 

transparent analyses of air quality, technological feasibility, and potential costs and benefits. The 

forthcoming Tier 3 proposed rulemaking package, which has not yet been published for comment, will 

contain extensive, detailed analyses of the rule's potential impacts on the refining and auto industries as 

well as its anticipated health and air quality benefits and potential impacts on refinery greenhouse gas 

emissions. The EPA will, of course, carefully consider and respond to all timely comments on the 

proposed rule before promulgating a final rule. 

Again, thank you for your letter. If you have further questions, please contact me or your staff may call 

Patricia Haman in EPA's Office of Congressional and Intergovernmental Relations at (202) 564-2806. 

Gimf' McCarthy 

Assistant Administrator
OFFICE OF


AIR AND RADIATION 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY


WASHINGTON, D.C. 20460

The Honorable Mary L. Landrieu 

United States Senate 

Washington, D.C. 20510 

Dear Senator Landrieu: 

Thank you for your letter of February 4, 2013, co-signed by four of your colleagues, expressing 

concerns with the U.S. Environmental Protection Agency's forthcoming proposed regulations for motor 

vehicle emissions and gasoline standards known as the "Tier 3" standards. 

The EPA is developing proposed Tier 3 standards to improve air quality by reducing harmful pollutants 

emitted from motor vehicles, and to create a harmonized national vehicle emissions control program. 

Similar to the Tier 2 standards referred to in your letter, we expect the proposed Tier 3 standards to be 

based on a "systems approach" that includes proposed vehicle emission standards as well as proposed 

reductions in gasoline sulfur content, Considering the vehicle and its fuel as an integrated system 

enables technologically feasible and cost-effective emission reductions beyond what would be possible 

looking at vehicle and fuel standards in isolation. 

At the time the Tier 2 standards were developed, there was not sufficient data on vehicle operation and 

emission performance with gasoline sulfur levels below 30 ppm. Since that time, it has been 

demonstrated that catalyst efficiency would be significantly improved with even lower sulfur levels, 

including for Tier 2 vehicles. The Tier 3 gasoline sulfur standards that we are considering proposing 

would require sulfur levels similar to that already being achieved in California, Europe, Japan, South 

Korea, and several other countries. Lower sulfur gasoline will lead directly to emission reductions and is 

necessary to operate the pollution control equipment to achieve new Tier 3 vehicle standards. 

The EPA understands the importance of potential cost impacts on refineries, and that is why we will 

include extensive refinery-by-refinery analyses of the costs associated with the proposed Tier 3 gasoline 

sulfur control program in the proposed rulemaking, and solicit comment. We estimate the cost of the 

forthcoming proposed standards to be on average about a penny per gallon. Our evaluation of gasoline 

sulfur control costs has undergone independent peer review and is corroborated by two independent 

studies (by Mathpro Inc. and Navigant Economics). The Baker & O'Brien study cited in your letter, 

which estimates a slightly higher average cost increase of 2.1 cents per gallon, is based on a number of 

problematic assumptions that bias the study towards overstatement of costs, including but not limited to 

a very stringent cap on gasoline sulfur content and a lack of programmatic flexibilities the EPA plans to 

propose.

Internet Address (URL) • http://www.epa.gov


RecycledlRecyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (MinImum 50% Poatconsumer content)
The proposed Tier 3 program we are considering would address significant public health issues that 

exist currently and are projected to continue in the future. The data and analysis detailing the need for 

and benefits of the proposed Tier 3 standards will be documented in the forthcoming notice of proposed 

rulemaking. By reducing motor vehicle emissions, the proposed standards would lead to improvements 

in ambient concentrations of harmful pollutants such as ozone and particulate matter (PM). Health 

benefits associated with reductions in ozoneand PM are well-established, and the proposed Tier 3 

program would lead to reductions in adverse health impacts such as respiratory symptoms in children, 

exacerbation of asthma and premature mortality. Further, implementation of the proposed Tier 3 

program would assist areas with attainment dates in 2018 and beyond in attaining and maintaining the 

National Ambient Air Quality Standards for ozone and may relieve areas from some of the burden 

associated with adopting additional local controls. 

It's important to emphasize that this would be a proposal, subject to stakeholder and public input 

through the notice and comment process. We agree that major rules such as Tier 3 require robust and 

transparent analyses of air quality, technological feasibility, and potential costs and benefits. The 

forthcoming Tier 3 proposed rulemaking package, which has not yet ben published for comment, will 

contain extensive, detailed analyses of the rule's potential impacts on the refining and auto industries as 

well as its anticipated health and air quality benefits and potential impacts on refinery greenhouse gas 

emissions. The EPA will, of course, carefully consider and respond to all timely comments on the 

proposed rule before promulgating a final rule. 

Again, thank you for your letter. If you have further questions, please contact me or your staff may call 

Patricia Haman in EPA's Office of Congressional and Intergovermnental Relations at (202) 564-2806. 

GinavIcCarthy 

Assistant Administrator
·^ıTED ST.ır^

^^^

^LPROTE^

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY


WASHINGTON, D.C. 20460

OFFICE OF


AIR AND RADIATION 

The Honorable Heidi Heitkamp 

United States Senate 

Washington, D.C. 20510 

Dear Senator Heitkamp: 

Thank you for your letter of February 4, 2013, co-signed by four of your colleagues, expressing 

concerns with the U.S. Environmental Protection Agency's forthcoming proposed regulations for motor 

vehicle emissions and gasoline standards known as the "Tier 3" standards. 

The EPA is developing proposed Tier 3 standards to improve air quality by reducing harmful pollutants 

emitted from motor vehicles, and to create a harmonized national vehicle emissions control program. 

Similar to the Tier 2 standards referred to in your letter, we expect the proposed Tier 3 standards to be 

based on a "systems approach" that includes proposed vehicle emission standards as well as proposed 

reductions in gasoline sulfur content. Considering the vehicle and its fuel as an integrated system 

enables technologically feasible and cost-effective emission reductions beyond what would be possible 

looking at vehicle and fuel standards in isolation. 

At the time the Tier 2 standards were developed, there was not sufficient data on vehicle operation and 

emission performance with gasoline sulfur levels below 30 ppm. Since that time, it has been 

demonstrated that catalyst efficiency would be significantly improved with even lower sulfur levels, 

including for Tier 2 vehicles. The Tier 3 gasoline sulfur standards that we are considering proposing 

would require sulfur levels similar to that already being achieved in California, Europe, Japan, South 

Korea, and several other countries. Lower sulfur gasoline will lead directly to emission reductions and is 

necessary to operate the pollution control equipment to achieve new Tier 3 vehicle standards. 

The EPA understands the importance of potential cost impacts on refineries, and that is why we will 

include extensive refinery-by-refinery analyses of the costs associated with the proposed Tier 3 gasoline 

sulfur control program in the proposed rulemaking, and solicit comment. We estimate the cost of the 

forthcoming proposed standards to be on average about a penny per gallon. Our evaluation of gasoline 

sulfur control costs has undergone independent peer review and is corroborated by two independent 

studies (by Mathpro Inc. and Navigant Economics). The Baker & O'Brien study cited in your letter, 

which estimates a slightly higher average cost increase of 2.1 cents per gallon, is based on a number of 

problematic assumptions that bias the study towards overstatement of costs, including but not limited to 

a very stringent cap on gasoline sulfur content and a lack of programmatic flexibilities the EPA plans to 

propose.

Internet Address (URL) • http://www.epa.gov


Recycled!Recyclable • Printed with Vegetable Oil Based inks on Recycled Paper (Minimum 50% Poatconsumer content)
The proposed Tier 3 program we are considering would address significant public health issues that 

exist currently and are projected to continue in the future. The data and analysis detailing the need for 

and benefits of the proposed Tier 3 standards will be documented in the forthcoming notice of proposed 

rulemaking. By reducing motor vehicle emissions, the proposed standards would lead to improvements 

in ambient concentrations of harmful pollutants such as ozone and particulate matter (PM). Health 

benefits associated with reductions in ozone and PM are well-established, and the proposed Tier 3 

program would lead to reductions in adverse health impacts such as respiratory symptoms in children, 

exacerbation of asthma and premature mortality. Further, implementation of the proposed Tier 3 

program would assist areas with attainment dates in 2018 and beyond in attaining and maintaining the 

National Ambient Air Quality Standards for ozone and may relieve areas from some of the burden 

associated with adopting additional local controls. 

It's important to emphasize that this would be a proposal, subject to stakeholder and public input 

through the notice and comment process. We agree that major rules such as Tier 3 require robust and 

transparent analyses of air quality, technological feasibility, and potential costs and benefits. The 

forthcoming Tier 3 proposed rulemaking package, which has not yet been published for comment, will 

contain extensive, detailed analyses of the rule's potential impacts on the refining and auto industries as 

well as its anticipated health and air quality benefits and potential impacts on refinery greenhouse gas 

emissions. The EPA will, of course, carefully consider and respond to all timely comments on the 

proposed rule before promulgating a final rule. 

Again, thank you for your letter. If you have further questions, please contact me or your staff may call 

Patricia Haman in EPA's Office of Congressional and Intergovernmental Relations at (202) 564-2806. 

Gina .4cCarthy 

Assistant Administrator
6

^,TEDSTAr^ ^^

A LPWTEC,

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY


WASHINGTON, D.C. 20460

OFFICE OF


AIR AND RADIATION 

The Honorable David Vitter 

United States Senate 

Washington, D.C. 20510 

Dear Senator Vitter: 

Thank you for your letter of February 4, 2013, co-signed by four of your colleagues, expressing 

concerns with the U.S. Environmental Protection Agency's forthcoming proposed regulations for motor 

vehicle emissions and gasoline standards known as the "Tier 3" standards. 

The EPA is developing proposed Tier 3 standards to improve air quality by reducing harmful pollutants 

emitted from motor vehicles, and to create a harmonized national vehicle emissions control program. 

Similar to the Tier 2 standards referred to in your letter, we expect the proposed Tier 3 standards to be 

based on a "systems approach" that includes proposed vehicle emission standards as well as proposed 

reductions in gasoline sulfur content. Considering the vehicle and its fuel as an integrated system 

enables technologically feasible and cost-effective emission reductions beyond what would be possible 

looking at vehicle and fuel standards in isolation. 

At the time the Tier 2 standards were developed, there was not sufficient data on vehicle operation and 

emission performance with gasoline sulfur levelsbelow 30 ppm. Since that time, it has been 

demonstrated that catalyst efficiency would be significantly improved with even lower sulfur levels, 

including for Tier 2 vehicles. The Tier 3 gasoline sulfur standards that we are considering proposing 

would require sulfur levels similar to that already being achieved in California, Europe, Japan, South 

Korea, and several other countries. Lower sulfur gasoline will lead directly to emission reductions and is 

necessary to operate the pollution control equipment to achieve new Tier 3 vehicle standards. 

The EPA understands the importance of potential cost impacts on refineries, and that is why we will 

include extensive refinery-by-refinery analyses of the costs associated with the proposed Tier 3 gasoline 

sulfur control program in the proposed rulemaking, and solicit comment. We estimate the cost of the 

forthcoming proposed standards to be on average about a penny per gallon. Our evaluation of gasoline 

sulfur control costs has undergone independent peer review and is corroborated by two independent 

studies (by Mathpro Inc. and Navigant Economics). The Baker & O'Brien study cited in your letter, 

which estimates a slightly higher average cost increase of 2.1 cents per gallon, is based on a number of 

problematic assumptions that bias the study towards overstatement of costs, including but not limited to 

a very stringent cap on gasoline sulfur content and a lack of programmatic flexibilities the EPA plans to 

propose.

Internet Address (URL) • http:I/www.epa.gov


Recycled/Recyclable • Printed with Vegetable OIl Based Inks on Recycled Paper (MInimum 50% Postconsumer Content)
The proposed Tier 3 program we are considering would address significant public health issues that 

exist currently and are projected to continue in the future. The data and analysis detailing the need for 

and benefits of the proposed Tier 3 standards will be documented in the forthcoming notice of proposed 

rulemaking. By reducing motor vehicle emissions, the proposed standards would lead to improvements 

in ambient concentrations of harmful pollutants such as ozone and particulate matter (PM). Health 

benefits associated with reductions in ozone and PM are well-established, and the proposed Tier 3 

program would lead to reductions in adverse health impacts such as respiratory symptoms in children, 

exacerbation of asthma and premature mortality. Further, implementation of the proposed Tier 3 

program would assist areas with attainment dates in 2018 and beyond in attaining and maintaining the 

National Ambient Air Quality Standards for ozone and may relieve areas from some of the burden 

associated with adopting additional local controls. 

It's important to emphasize that this would be a proposal, subject to stakeholder and public input 

through the notice and comment process. We agree that major rules such as Tier 3 require robust and 

transparent analyses of air quality, technological feasibility, and potential costs and benefits. The 

forthcoming Tier 3 proposed rulemaking package, which has not yet been published for comment, will 

contain extensive, detailed analyses of the rule's potential impacts on the refining and auto industries as 

well as its anticipated health and air quality benefits and potential impacts on refinery greenhouse gas 

emissions. The EPA will, of course, carefully consider and respond to all timely comments on the 

proposed rule before promulgating a final rule. 

Again, thank you for your letter. If you have further questions, please contact me or your staff may call 

Patricia Haman in EPA's Office of Congressional and Intergovernmental Relations at (202) 564-2806. 

Gina!vfcCarthy 

Assistant Administrator
^^^ ^^TEO STA^^

^AL p^oTE

^

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY


WASHINGTON, D.C. 20460

OFFICE OF


AIR AND RADIATION 

The Honorable John Hoeven 

United States Senate 

Washington, D.C. 20510 

Dear Senator Hoeven: 

Thank you for your letter of February 4, 2013, co-signed by four of your colleagues, expressing 

concerns with the U.S. Environmental Protection Agency's forthcoming proposed regulations for motor 

vehicle emissions and gasoline standards known as the "Tier 3" standards. 

The EPA is developing proposed Tier 3 standards to improve air quality by reducing harmful pollutants 

emitted from motor vehicles, and to create a harmonized national vehicle emissions control program. 

Similar to the Tier 2 standards referred to in your letter, we expect the proposed Tier 3 standards to be 

based on a "systems approach" that includes proposed vehicle emission standards as well as proposed 

reductions in gasoline sulfur content. Considering the vehicle and its fuel as an integrated system 

enables technologically feasible and cost-effective emission reductions beyond what would be possible 

looking at vehicle and fuel standards in isolation. 

At the time the Tier 2 standards were developed, thre was not sufficient data on vehicle operation and 

emission performance with gasoline sulfurlevels below 30 ppm. Since that time, it has been 

demonstrated that catalyst efficiency would be 'significantly improved with even lower sulfur levels, 

including for Tier 2 vehicles. The Tier 3 gasoline sulfur standards that we are considering proposing 

would require sulfur levels similar to that already being achieved in California, Europe, Japan, South 

Korea, and several other countries. Lower sulfur gasoline will lead directly to emission reductions and is 

necessary to operate the pollution control equipment to achieve new Tier 3 vehicle standards. 

The EPA understands the importance of potential cost impacts on refineries, and that is why we will 

include extensive refinery-by-refinery analyses of the costs associated with the proposed Tier 3 gasoline 

sulfur control program in the proposed rulemaking, and solicit comment. We estimate the cost of the 

forthcoming proposed standards to be on average about a penny per gallon. Our evaluation of gasoline 

sulfur control costs has undergone independent peer review and is corroborated by two independent 

studies (by Mathpro Inc. and Navigant Economics). The Baker & O'Brien study cited in your letter, 

which estimates a slightly higher average cost increase of 2.1 cents per gallon, is based on a number of 

problematic assumptions that bias the study towards overstatement of costs, including but not limited to 

a very stringent cap on gasoline sulfur content and a lack of programmatic flexibilities the EPA plans to 

propose.

Internet Address (URL) • http://www.epa.gov


Recycled!Recyclable • Printed with Vegetable Oil Based inks on Recycled Paper (MinImum 50% Postconsumer content)
The proposed Tier 3 program we are considering would address significant public health issues that 

exist currently and are projected to continue in the future. The data and analysis detailing the need for 

and benefits of the proposed Tier 3 standards will be documented in the forthcoming notice of proposed 

rulemaking. By reducing motor vehicle emissions, the proposed standards would lead to improvements 

in ambient concentrations of harmful pollutants such as ozone and particulate matter (PM). Health 

benefits associated with reductions in ozone and PM are well-established, and the proposed Tier 3 

program would lead to reductions in adverse health impacts such as respiratory symptoms in children, 

exacerbation of asthma and premature mortality. Further, implementation of the proposed Tier 3 

program would assist areas with attainment dates in 2018 and beyond in attaining and maintaining the 

National Ambient Air Quality Standards for ozone and may relieve areas from some of the burden 

associated with adopting additional local controls. 

It's important to emphasize that this would be a proposal, subject to stakeholder and public input 

through the notice and comment process. We agree that major rules such as Tier 3 require robust and 

transparent analyses of air quality, technological feasibility, and potential costs and benefits. The 

forthcoming Tier 3 proposed rulemaking package, which has not yet been published for comment, will 

contain extensive, detailed analyses of the rule's potential impacts on the refining and auto industries as 

well as its anticipated health and air quality benefits and potential impacts on refinery greenhouse gas 

emissions. The EPA will, of course, carefully consider and respond to all timely comments on the 

proposed rule before promulgating a final rule. 

Again, thank you for your letter. If you have further questions, please contact me or your staff may call 

Patricia Haman in EPA's Office of Congressional and Intergovernmental Relations at (202) 564-2806. 

Gina 4cCarthy 

Assistant Administrator