United States

Environmental Protection

Agency

Air and Radiation EPA420-R-00-024

December 2000

Control of Emissions of

Hazardous Air Pollutants

from Mobile Sources:

Response to Comments

 Printed on Recycled Paper
EPA420-R-00-024

December 2000

Control of Emissions of Hazardous

Air Pollutants from Mobile Sources:

Response to Comments

Assessment and Standards Division

Office of Transportation and Air Quality

U.S. Environmental Protection Agency

Docket A2000-12
i

December 20, 2000

RESPONSE TO COMMENTS DOCUMENT

CONTROL OF EMISSIONS OF HAZARDOUS AIR POLLUTANTS

FROM MOBILE SOURCES

Table of Contents

Page

ISSUE 1: GENERAL POSITION STATEMENTS .................................. 1

1.1: Supports Rule ................................................... 1

1.2: Opposes Rule ................................................... 1

ISSUE 2: ADEQUACY OF THE PROPOSAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1: Statutory Obligations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.2: Adequacy of Rule to Address Public Health & Welfare Concerns ........... 6

2.3: Environmental Justice Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.4: Consistency with UAT Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

ISSUE 3: DESIGNATION OF MSATS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.1: General Comments on MSAT List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2: Methodology for Identifying MSATs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3: Compounds on MSAT List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3.1: Specific Pollutants to Exclude from List . . . . . . . . . . . . . . . . . . . . . . 13

3.3.2: Additional Pollutants that EPA Should List . . . . . . . . . . . . . . . . . . . . 15

3.3.3: Listing of Diesel Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

ISSUE 4: CURRENT CONTROLS ON MSAT EMISSIONS . . . . . . . . . . . . . . . . . . . . . . . . 19

4.1: On-highway Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.2: Off-highway Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

ISSUE 5: VEHICLE-BASED CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

ISSUE 6: FUEL STANDARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

6.1: General Comments to Support Anti-Backsliding Program . . . . . . . . . . . . . . . . 21

6.2: General Comments Opposing Anti-Backsliding Program . . . . . . . . . . . . . . . . 22

6.3: State Pre-emption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

6.4: California Exemption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.5: Form of Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.5.1: Benzene Content Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.5.2: Toxics Performance Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.5.3: Benzene Emissions Standard . . . . . . . . . . . . . . . . 27

6.5.4: National Average-Based vs. Refinery-Based Standards . . . . . . . . . 28

6.5.5: Alternative Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.6: Ability to Meet Baseline Levels at No Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

6.7: Start Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

6.8: Separate Standards for RFG & CG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.9: Incremental Volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
RESPONSE TO COMMENTS DOCUMENT

TIER 2 MOTOR VEHICLE EMISSION STANDARDS AND

 GASOLINE SULFUR CONTROL REQUIREMENTS

Table of Contents (cont.)

Page

ii

6.10: Appropriate Baseline Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

6.10.1: Proposed 1998-99 Baseline Period . . . . . . . . . . . . . . . . . . . . . . . . 38

6.10.2: Alternative Baseline Periods and Adjustments . . . . . . . . . . . . . . . . 40

6.10.3: Petitions for Alternative Baseline . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

6.11: Flexibility Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

6.11.1: 1- or 2-year Compliance Period . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

6.11.2: 1-year Carryover Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

6.11.3: Trading Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

6.11.4: Hardship Waiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

6.11.5: Aggregation of Refineries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

6.11.6: Other Flexibility Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

6.12: Testing, Reporting and Recordkeeping, and Compliance/Enforcement Issues49

6.13: Economic Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

6.13.1: Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

6.13.2: Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.14: Other Fuel Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

6.14.1: Anti-dumping Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

6.14.2: Other Fuel Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.15: SBREFA and Small Refiner Flexibility Options . . . . . . . . . . . . . . . . . . . . . . . 59

ISSUE 7: TECHNICAL ANALYSIS PLAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

ISSUE 8: PROPOSED FUTURE RULEMAKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

ISSUE 9: COMMENTER SUPPORTS OTHER'S COMMENTS . . . . . . . . . . . . . . . . . . . . . 68
CONTROL OF EMISSIONS OF HAZARDOUS AIR POLLUTANTS

FROM MOBILE SOURCES: RESP0NSE TO COMMENTS

INTRODUCTION

Air toxics, which are also known as “hazardous air pollutants” or HAPs, are those

pollutants known or suspected to cause cancer or other serious health or environmental

effects. To address concerns about the potentially serious impacts of hazardous air

pollutants on public health and the environment, the Clean Air Act (the Act) as amended in

1990, includes a number of provisions that have led EPA to characterize, prioritize, and

control these emissions as appropriate. This rule on the control of hazardous air pollutants

from mobile sources addresses air toxics emissions from mobile sources in several ways. 

First, we identify 21 Mobile Source Air Toxics (MSATs), including various VOCs as well as

metal compounds and diesel particulate matter + diesel exhaust organic gases (collectively

DPM + DEOG). Second, we examine the mobile source contribution to national inventories

of these compounds and the impacts of existing and proposed mobile source control

programs. Third, we set new gasoline toxic emission performance standards which require

refiners to maintain current levels of overcompliance with RFG and anti-dumping toxic

emission performance requirements. Finally, we establish a process to continue to conduct

research and analysis on mobile source air toxics. This includes a Technical Analysis Plan

which we will implement to continue to conduct research and analysis on mobile source air

toxics. Based on the results of that research, EPA will conduct a future rulemaking, to be

completed no later than July 1, 2004, in which we will revisit the feasibility and need for

additional air toxics controls for nonroad and highway engines and vehicles and their fuels

EPA proposed this rule on August 4, 2000, at 65 FR 48058. The proposal

announced the opportunity for written public comment until September 20, 2000. The

proposal also provided notice of public hearing, which was held on August 21, 2000 in

Romulus, Michigan. 

Complete transcripts of the public hearings and the full text of each comment letter,

along with supporting information used in developing the regulation, are listed in Docket No.

A-2000-12. This docket is available for public inspection and copying between 8:00 a.m. and

5:30 p.m., Monday through Friday, excluding government holidays, at Room M-1500,

Waterside Mall, 401 M Street, S.W., Washington, D.C.

This document summarizes the written and oral comments submitted at the public

hearing as well as the comment letters received during the public comment period (Docket

Category IV-D), and records EPA's responses to those comments. In most cases in this

document, EPA has listed all of the commenters who made a specific comment. In other

instances, the Agency may have identified one or a representative number of commenters. 

The reader should note that many of the most significant comments are also addressed in

the preamble for the final rule. Where appropriate, we have included cross-references in this

document to the corresponding discussion in the preamble.

EPA received comments from a wide variety of stakeholders, including gasoline

refiners, marketers, distributors and retailers; automobile manufacturers and parts suppliers;

industry research and trade groups; state and local agencies; environmental organizations;

and private citizens. A copy of each comment letter received is included in the rulemaking
Response to Comments

Page iv

docket. A list of commenters and the EPA docket item number assigned to their

correspondence is also included in the docket. All of the comments have been carefully

considered and, where appropriate, changes have been made to the final regulation in

response to these comments.

Comments within a particular Issue (or Subissue) are divided into specific comments

(such as "Comment A" or Comment "A.1"), so that comments and responses on specific

aspects of an Issue (Subissue) are grouped together. The lettering and numbering of these

comments preserves the Agency's internal classification of points raised on a particular issue

in the various comment letters. This approach allows for cross-referencing between

responses to related comments. In certain places, comments have been consolidated in a

logical manner for the Agency's response. Even in these consolidated comments, the

comment identification in this document preserves the Agency's internal lettering and

numbering identification system within an issue (for instance a comment may be identified as

"Comments A, F, G, N, and S" if those individual comments have a single consolidated

response.
Response to Comments

December 20, 2000

Page 1

ISSUE 1: GENERAL POSITION STATEMENTS

1.1: Supports Rule 

(A) Expressed limited support for the rule as proposed by EPA.

(1) While providing some support, commenters recommended several significant

changes, including tightening the benzene requirement (see Issue 2.2 for

more detailed comments) or expanding the rule to cover all aromatic

compounds (see Issue 6.14.2).

Letters:

Bluewater Network (IV-D-29) p. 1

Commonwealth of MA DEP (IV-D-13) p. 2

Oregon Environmental Council (IV-D-9) p. 1

(2) Commenter provides discussion of personal health concerns raised by

MSATs and other forms of pollution.

Letters:

Norman White (IV-G-1) p. 1

Response to issues 1.1(A)(1) and (2): Several commenters expressed general support for

our proposed program. Many of them also urged us to finalize standards that would go

beyond the anti-backsliding standards we proposed and set tighter gasoline benzene limits to

reduce mobile source benzene emissions. After consideration of all comments, we are

finalizing a two-step approach to air toxics control. The first step retains the proposed

gasoline air toxics anti-backsliding approach but includes a much broader set of gaseous air

toxics. By requiring refiners to maintain their 1998-2000 average gasoline toxics

performance levels, the standards we are finalizing focus on the five toxics used in the

Complex Model to demonstrate performance (benzene, formaldehyde, acetaldehyde, 1,3-

butadiene, and POM) instead of only benzene. Thus, the mass of air toxics placed under the

anti-backsliding controls is substantially increased. This approach offers broad protection to

public health because all five of these are toxics are known or probable human carcinogens. 

At the same time, we remain sensitive to the potentially serious effects exposure to air toxics

may have on human health. Consequently, in the second step of this approach we will

implement the Technical Analysis Plan described in Section VII of the preamble for this rule. 

Through this Plan we will continue to improve our understanding of the risk posed by air

toxics to public health and welfare. We will also evaluate the need for and appropriateness

of additional mobile source air toxics controls for on-highway vehicles and their fuels. Based

on the information developed through this technical analysis plan, we will conduct a future

rulemaking to be completed no later than July 1, 2004. During this rulemaking, EPA also

intends to evaluate emissions and potential strategies relating to hazardous air pollutants

from nonroad engines and vehicles and nonroad sources.

(B) Supports major aspects of the proposal.
Response to Comments

December 20, 2000

Page 2

(1) See comments on specific topics in Issues 2-8.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 1

Alliance of Automobile Manufacturers (IV-F-1) p. 59

Association of International Automobile Manufacturers (IV-D-7) p. 1

Engine Manufacturers Association (IV-D-39) p. 10

Engine Manufacturers Association (IV-F-1) p. 10

Response to issue 1.1(B)(1): Commenters from the engine and vehicle manufacturing

industry generally supported our conclusion that additional vehicle-based controls are not

warranted at this time. Additional support for our conclusion that our Tier 2 light-duty vehicle

program and our proposed heavy-duty engine and vehicle standards achieve the greatest

degree of toxics control achievable at this time is provided in the preamble to this final rule

and our Technical Support Document.

1.2: Opposes Rule 

(A) Rule is not sufficient to address concerns associated with MSATs.

(1) See commenters' detailed concerns under Issues 2.1-2.4.

Letters:

Clean Air Network, et al (IV-D-38) p. 1

Consumer Policy Institute (IV-D-8) p. 1

EarthJustice Legal Defense Fund (IV-D-32) p. 1

IL EPA (IV-D-28) p. 2

Puget Sound Clean Air Agency (IV-D-27) p. 1

STAPPA, ALAPCO (IV-D-22) p. 1-2

STAPPA, ALAPCO (IV-F-1) p. 44

Response to issue 1.2(A)(1): Section 202(l)(2) of the Clean Air Act calls on EPA to set

standards for emissions of hazardous air pollutants from motor vehicles and their fuels that

“reflect the greatest degree of emission reduction achievable through the application of

technology which will be available, taking into consideration [existing standards] and the

costs of the technology, and noise, energy, and safety factors, and lead time.” Today’s rule

adopts an anti-backsliding program that is an appropriate near-term control under this

provision. The anti-backsliding requirement can be implemented using existing technology,

at negligible costs, with little lead time. More stringent near-term controls do not appear

reasonable at this time. Requiring more than an anti-backsliding standard could require

refinery upgrades that could not be completed without additional lead time. In the near term,

refineries are already planning and investing in capital improvements and pursuing the

permitting necessary to upgrade their facilities to meet our regulations limiting the sulfur

content of fuels. While we lack the information to fully assess the benefits and costs of

further controls in the 2002 time frame, we have serious concerns that further toxics control in

this time frame could interfere with refiners’ planning and affect their ability to meet our sulfur

standards.
Response to Comments

December 20, 2000

Page 3

Although we conclude that additional near-term controls are not reasonable under

section 202(l)(2), there may be additional reductions of MSAT emissions that can be

achieved in the long-term. We are not ready, however to address these possible long-term

controls in this rulemaking. There is a considerable amount of uncertainty about the

effectiveness and costs of vehicle, fuel, and nonroad controls as well as about exposure and

risk for sensitive subpopulations, the range of total public exposure to air toxics, and the

inventory impacts of nonroad sources. We will collect information about these issues as part

of the Technical Analysis Plan we will implement as described in Section VII of the preamble

for this rule and will use this information in a future mobile source air toxics rulemaking to be

completed no later than July 1, 2004.

While several commenters expressed concern that this two-step approach delays

more stringent action, we believe it is appropriate because it allows us to design long-term

controls that will optimally reduce exposure to mobile source air toxics while implementing

controls immediately that ensure that the toxics emissions performance of gasoline does not

deteriorate in response to potential changes in fuel production processes. 

(B) The rulemaking is without merit.

(1) The rule seeks to impose regulation on an already heavily burdened industry

while achieving no public health or demonstrated air quality benefit. Some of

these commenters added that EPA has failed to meet the basic regulatory

development requirement: to analyze the cost effectiveness of its regulations.

Letters:

American Petroleum Institute (IV-D-21) p. 1

American Petroleum Institute (IV-F-1) p. 33

Chevron (IV-D-34) p. 1

ExxonMobil (IV-D-16) p. 1

Marathon Ashland Petroleum, LLC (IV-D-15) p. 4-5

Murphy Oil Corporation (IV-D-17) p. 4-5

National Petrochemical and Refiners Association (IV-D-33) p. 1-2

Phillips Petroleum Company (IV-D-20) p. 2, 6

Silver Eagle Refining, Inc. (IV-D-18) p. 1

Response to issue 1.2(B)(1): The Clean Air Act requires EPA to set controls for at least

benzene and formaldehyde that “reflect the greatest degree of emission reduction achievable

through the application of technology which will be available, taking into consideration

[existing standards] and the costs of the technology, and noise, energy, and safety factors,

and lead time.” The standards we are finalizing are designed to be a reasonable approach to

ensure that there is no backsliding on the toxics performance of gasoline. They are clearly

achievable in the near-term without imposing burdens on the refining industry because they

require simply that refiners maintain their current toxics performance levels and so impose

only negligible costs, if any. To fail to promulgate these standards would be to ignore the

clear direction of the Act. With regard to long-term controls, we will assess their costs and

benefits as part of the Technical Analysis Plan and our future rulemaking. Responses to

specific concerns about our cost-benefit analysis can be found under Issue 6.13.1, below.
Response to Comments

December 20, 2000

Page 4

(2) The benzene content of gasoline is already limited under reformulated

gasoline and anti-dumping rules and it is not clear from the NPRM why this

level of control is not sufficiently protective of public health. Moreover, EPA

already expects the level of over-compliance to continue and even improve,

which appears to make a rule unnecessary. (See related comments under

Issue 6.13.2 about the lack of benefits.)

Letters:

U.S. Small Business Administration (IV-D-26) p. 2

American Petroleum Institute (IV-D-21) p. 2, app p. 3

Response to issue 1.2(B)(2): Because the air toxics addressed by the gasoline toxics

performance standard are known or probable human carcinogens, it is difficult to say what

level of control is sufficient to protect public health. What is clear, however, is that it is

desirable to avoid increases in exposure to these pollutants. The standards being finalized

will help prevent this from happening. As explained in our preamble and Technical Support

Document, the trend appears to be toward continued and perhaps further over-compliance

with the toxics requirements of the federal reformulated gasoline and anti-dumping programs. 

However, instead of making this rule unnecessary, these trends support our conclusion that

tighter standards may be achievable in the long term since some of the technologies used to

achieve current levels of over-compliance may be applicable to broader segments of the

refining industry. Consequently, we will explore additional fuel-based air toxics controls in

our Technical Analysis Plan and will address such controls in our July 2004 rulemaking. 
Response to Comments

December 20, 2000

Page 5

ISSUE 2: ADEQUACY OF THE PROPOSAL

2.1: Statutory Obligations 

(A) EPA has already met its statutory obligations, and is not required to further

regulate air toxics at this time.

(1) Any obligation under Section 202(l) to promulgate MSAT rules was met when

EPA promulgated the 1994 RFG/anti-dumping rulemaking. This point is

especially apparent given that there are no benefits assumed under this

proposal. Thus, EPA is under no further statutory or judicial obligation to

promulgate additional MSAT rules.

Letters:

American Petroleum Institute (IV-D-21) p. 3

American Petroleum Institute (IV-F-1) p. 34, 37-38

Chevron (IV-D-34) p. 1

ExxonMobil (IV-D-16) p. 1

Marathon Ashland Petroleum, LLC (IV-D-15) p. 5-6

Murphy Oil Corporation (IV-D-17) p. 5-6

Response to issue 2.1(A)(1): Our consent decree requires that we promulgate the

regulations described in section 202(l)(2). The regulations described in this section must

contain standards that respresent the greatest degree of emissions reductions achievable

considering the availability of the technology, cost, lead time and other factors. Our analysis

demonstrates that the current RFG and anti-dumping toxics performance standards do not

represent the greatest degree of emissions reductions achievable. We therefore disagree

with commenter’s assertion that nothing more is required.

We also think it unlikely that Congress expected RFG to satisfy our obligation to

consider fuel-based controls in 202(l)(2). Commenter’s suggestion would render 202(l)(2)

duplicative and meaningless. In fact, 202(l)(2) provides a broader scope for addressing toxics

for vehicles and fuels, a different criteria for determining the appropriate level of control and a

different time frame for action. If Congress had expected 1994 RFG/anti-dumping program

to satisfy its clearly-expressed concern about public exposure to air toxics, it would not have

required the Agency to establish, at a minimum, standards applying to benzene and

formaldehyde emissions in 1995 under section 202(l).

Finally, even if we could argue that, because of our RFG controls and anti-dumping,

nothing further is required under 202(l)(2), there is nothing in that section that precludes

further controls. Section 202(l)(2) clearly states that EPA shall “promulgate (and from time to

time revise” regulations...” In other words, Congress intended EPA to consider control of

emissions of hazardous air pollutants from motor vehicles and their fuels as an ongoing air

pollution issue. The Agency must consider potential controls and determine whether those

controls “reflect the greatest degree of emission reduction achievable through the application

of technology which will be available, taking into consideration [existing standards] and the

costs of the technology, and noise, energy, and safety factors, and lead time.” 
Response to Comments

December 20, 2000

Page 6

As to the benefits of this program, while it is true that we have not claimed that this

ani-backsliding program will result in some quantifiable emissions reduction benefit, we

disagree with the suggestion that there are no benefits from preventing backsliding. By

ratcheting down the toxics performance standards, we have ensured that emissions

performance will not deteriorate below today’s levels. Without today’s anti-backsliding

program, the current standards would leave room for toxics emissions from gasoline-fueled

motor vehicles to increase by 70,000 tons per year over 1996 inventory levels. In addition,

as noted by Environmental Systems Products in their comments (IV-D-25, p. 12-13), the

legislative history of the Act suggests that the benefits of the standards EPA would establish

under Section 202(l)(2) would be in addition to benefits resulting from standards established

under other provisions of the Act. With regard to the benefits of this mobile source air toxics

rule, there are air quality and public health benefits associated with preserving the existing

over-compliance with the federal reformulated gasoline and anti-dumping requirements.

(2) EPA has already met the legal standard for controlling HAP emissions from

mobile sources through the aggressive and technology-forcing Tier 2 and

HDDE requirements which "reflect the greatest degree of emissions reduction

achievable through the application of technology which [will be] available for

the model year to which such standards apply."

Letters:

International Truck and Engine Corp. (IV-D-30) p. 2-3

Response to issue 2.1(A)(2): We agree that our Tier 2 light-duty vehicle program and our

proposed heavy-duty engine and vehicle standards achieve the greatest degree of toxics

control achievable at this time. However, as noted above, Congress instructed EPA to “from

time to time” review these mobile source air toxics standards, and we will revisit the

technological feasibility and need for additional vehicle and fuel controls in a future

rulemaking, in 2003-2004. 

(B) EPA's proposed MSAT regulations fail to meet the statutory mandate under the

CAA.

(1) Section 202(l) of the CAA requires EPA to address air toxics by setting motor

vehicle and fuel standards which "reflect the greatest degree of emission

reduction achievable through the application of technology which will be

available...." EPA has identified the threats posed by MSATs while pushing

forward only with regulation of criteria pollutants from mobile sources. EPA

has failed to deal comprehensively with emissions of criteria and toxic

pollutants in its rulemaking, and now suggests it may be infeasible to require

further vehicle or fuel controls. EPA's narrow interpretation of its obligation

under 202(l) falls far short of a comprehensive assessment of the air quality

and public health impact of mobile sources burning gasoline and diesel fuels. 

One commenter added that EPA appears to establish as a precondition for

adopting additional requirements under section 202(l) that section 202(a)

controls are ineffective at controlling MSATs. That type of precondition is not

required by the statute and is erroneous.
Response to Comments

December 20, 2000

Page 7

Letters:

Clean Air Network, et al (IV-D-38) p. 1-2

Consumer Policy Institute (IV-D-8) p. 1-2

EarthJustice Legal Defense Fund (IV-D-32) p. 3-6, 8-9

IL EPA (IV-D-28) p. 2

NESCAUM (IV-D-10) p. 7-8, 10

STAPPA, ALAPCO (IV-D-22) p. 1-2

STAPPA, ALAPCO (IV-F-1) p. 43-44

Response to issue 2.1(B)(1): Section 202(l)(2) instructs us to set standards to control

hazardous air pollutants from motor vehicles, motor vehicle fuels, or both. These standards,

which may be revised from time to time, are to reflect the greatest degree of emission

reduction achievable through the application of technology which will be available, taking into

consideration the motor vehicle standards established under Section 202(a) of the Act, the

availability and cost of the technology, and noise, energy and safety factors, and lead time. 

The regulations are to apply, at a minimum, to benzene and formaldehyde emissions, and

are to be set under Section 202(a) or 211(c) of the Act.

We disagree with the assertion that we are suggesting it is infeasible to require

further vehicle or fuel controls, or that we are establishing as a precondition for adopting

additional requirements that the Section 202(a) controls are ineffective at controlling MSATs. 

As described in our preamble and in the Technical Support document for this rulemaking, we

believe that the standards being finalized represent the greatest degree of emission

reductions achievable in the short term. There may be vehicle- and fuel-based opportunities

in the future to achieve additional MSAT emission reductions. However, because there is a

considerable amount of uncertainty about the effectiveness and costs of vehicle, fuel, and

nonroad controls as well as about exposure and risk for sensitive subpopulations, the range

of total public exposure to air toxics, and the inventory impacts of nonroad sources, we do not

believe it is reasonable to establish long-term standards at this time. We will collect

information about these issues as part of the Technical Analysis Plan we will implement as

described in Section VII of the preamble for this rule and will use this information in a future

mobile source air toxics rulemaking to be completed no later than July 1, 2004. 

(2) The serious public health threats associated with MSATs in urban areas and

the clear statutory mandate of the CAA warrant immediate action by EPA. 

The Agency relies on mass emission reductions of toxics projected from

previous regulations. For health risks many times over health based

thresholds, mass emissions reductions are an insufficient measure of the

effectiveness of control programs. The absence of any demonstration of the

health risks for each U.S. urban area, and the long time period (until 2020) to

realize the expected mass emissions reductions from existing control

programs demonstrate the inadequacies of the proposal to protect public

health. EPA cannot justify waiting another three years to take action on

MSATs.

Letters:

Consumer Policy Institute (IV-D-8) p. 1-2
Response to Comments

December 20, 2000

Page 8

Response to issue 2.1(B)(2): As noted in the response to Issue 2.1.B(1) above, any action

that we take to reduce emissions of hazardous air pollutants from motor vehicles and their

fuels in response to the public health threats associated with MSAT emissions in urban areas

must meet the criteria of Section 202(l) of the Act. These criteria are clear: The standards set

by EPA must reflect “reflect the greatest degree of emission reduction achievable through the

application of technology which will be available, taking into consideration [existing

standards] and the costs of the technology, and noise, energy, and safety factors, and lead

time.” To fulfill our statutory obligation, we analyzed vehicle- and fuel-based control options

to determine if further reduction were achievable. Based on this review, we concluded that a

new anti-backsliding fuel measure satisfied these criteria in the near-term and that we could

not reasonably establish long-term fuel controls without additional information. Our analysis

of vehicle-based controls led us to conclude that our promulgated and proposed vehicle

controls satisfy the criteria in 202(l)(2). These conclusions were not based on a

determination that these controls will achieve a sufficient level of emissions reductions, but

instead were based on a evaluation of the achievability of further reductions considering the

availaibility of technology, cost, lead time and the other criteria in 202(l)(2). 

At the same time, we are sensitive to the potentially serious effects exposure to air

toxics may have on human health. Consequently, we will implement the Technical Analysis

Plan described in Section VII of the preamble for this rule. Through this Plan we will continue

to improve our understanding of the risk posed by air toxics to public health and welfare. We

will also evaluate the need for and appropriateness of additional mobile source air toxics

controls for on-highway and nonroad sources, and their fuels. Based on the information

developed through this technical analysis plan, we will conduct a future rulemaking to be

completed no later than July 1, 2004.

(3) The CAA requires that the regulations at a minimum apply to emissions of

benzene and formaldehyde. Yet in contrast to this clear direction from

Congress, EPA chose to consider only a benzene fuel control program in this

proposed rule. One commenter notes that EPA included no analysis of

formaldehyde fuel-based controls, and has had ample opportunity to do so.

Letters:

EarthJustice Legal Defense Fund (IV-D-32) p. 7-8

IL EPA (IV-D-28) p. 2

NESCAUM (IV-D-10) p. 2-3

Response to issue 2.1(B)(3): Several commenters urged us to consider establishing

controls for additional MSATs instead of focusing only on benzene. The standards we are

finalizing take these comments into account by setting toxics emissions performance

standards for gasoline instead of just a benzene standard. By requiring refiners to maintain

their 1998-2000 average gasoline toxics performance levels, the standards we are finalizing

focus on the five toxics used in the Complex Model to demonstrate performance (benzene,

formaldehyde, acetldehyde, 1,3-butadiene, and POM) instead of only benzene. Thus, the

mass of air toxics placed under anti-backsliding is substantially increased. It also offers

broader protection to public health because all five of these are toxics are known or probable

human carcinogens.
Response to Comments

December 20, 2000

Page 9

(4) Reliance on measures already taken and the capping of benzene levels at

1998-99 levels do not adequately address areas such as the Puget Sound

region that have fuel benzene concentrations above the national average and

have not enjoyed the benefits of reformulated gasoline.

Letters:

Puget Sound Clean Air Agency (IV-D-27) p. 1

Response to issue 2.1(B)(4): We recognize that one of the potential drawbacks of setting

an anti-backsliding standard is that areas that currently have high benzene concentrations

may not see a reduction in their levels. However, we believe the final standards adopted in

this rule do not alter current state authority to establish more stringent state standards for fuel

benzene. More specifically, because we are promulgating toxics performance requirements

that are identical in form to the toxic performance standards already in place, today’s rule

does not change the ability of States to regulate other gasoline characteristics or

components. As discussed in the NPRM, we believe a toxics performance requirement may

not cause States to be prohibited by section 211(c)(4) of the Act from setting their own fuel

benzene standard. Note, however, that any such State fuel benzene standard could only be

set for conventional gasoline because the reformulated gasoline regulations impose a federal

benzene standard on RFG, thus preempting States from setting a more stringent RFG

benzene standard.

(5) The text and statutory history of section 202(l) clearly contemplate that the

rules will provide air quality benefits over and above those obtained from

implementing other sections of the Act. A benzene cap that locks in current

practice cannot meet that statutory mandate.

Letters:

Environmental Systems Products (IV-D-25) p. 12-13

Response to issue 2.1(B)(5): The statute requires that we adopt controls that represent the

greatest degree of emissions reductions achievable. We have concluded that our vehiclebased controls fulfill this statutory requirement, and that further control are not appropriate at

this time. For fuel-based controls, we determined that the current RFG and anti-dumping

toxics performance standards do not reflect the greatest degree of emission reduction

achievable. Therefore we are adopting new anti-backsliding requirement. These standards

will ensure continued reductions of toxics emissions beyond those currently required. At the

same time, we have concluded that additional controls are not appropriate in the near term. 

As described in the preamble and Technical Support Document for this rule, the gasoline

toxics performance standard being finalized provides benefits over and above those obtained

from implementing other sections of the Act because it captures current levels of overcompliance with those other programs and will prevent refiners from increasing their toxics

emissions up to the limits contained in the federal reformulated gasoline and anti-dumping

programs.

(6) EPA is required to evaluate at least a 0.6% or 1% benzene cap as

"achievable" under 202(l). EPA also needs to consider control measures for
Response to Comments

December 20, 2000

Page 10

non-benzene HAPs and not just order a "toxics emission performance

standard." Individual caps for these pollutants must be considered. Likewise,

EPA fails to explain how the proposal addresses metals. If they are primarily

from lube oils, EPA fails to address the possibility of lube oil standards. 

Similarly, EPA suggests a relationship between diesel fuel and aldehydes

with dioxin/furans, but fails to analyze whether the standards it proposes

represent the greatest degree of emission reduction for these HAPs. EPA's

failure to consider vehicle standards also documents EPA's failure to analyze

whether the standards utilize the greatest degree of reductions possible. 

(See related comments under Issue 5.)

Letters:

EarthJustice Legal Defense Fund (IV-D-32) p. 4-5

Response to issue 2.1(B)(6): With regard to evaluating a 0.6% or 1% benzene cap,

Section 202(l)(2) does not require us to evaluate all possible control measures. Instead, we

are required to establish additional control measures that “reflect the greatest degree of

emission reduction achievable through the application of technology which will be available,

taking into consideration [existing standards] and the costs of the technology, and noise,

energy, and safety factors, and lead time.” As we explain in the preamble and Technical

Support document for this rule, the standards that are being finalized take immediate steps to

address toxics emissions from fuels in the near-term. This is a reasonable control on toxics

emissions from fuels because the technology to maintain the current toxics performance of

gasoline produced at each refinery is already available and continued compliance will not be

costly even with implementation of our recently adopted sulfur controls. We do not believe it

is reasonable to establish more stringent controls in this near-term time frame. First, the lead

time is too short to allow for investments and upgrading of refinery equipment in any

significant manner. Second, we have recently adopted, or proposed to adopt, two

regulations that will achieve very significant emissions reductions by setting tight limits on the

sulfur content of fuels used in on-highway vehicles. To comply with these new regulations,

industry is already planning and investing in capital improvements and pursuing the

necessary permitting to upgrade their refineries. 

We have serious concerns that further toxics controls in the 2002 time frame could

interfere with refiners’ planning and affect their ability to meet our recently promulgated, or

proposed, sulfur standards. Nevertheless, we believe it is desirable to act over a reasonably

short time frame to guarantee toxics controls in the near-term. We plan to address the

sufficiency of these controls and the appropriateness of further controls in a future

rulemaking. We lack a sufficient basis that would support further steps as part of this

rulemaking and allow us to conduct the evaluation of cost and energy considerations

required by §202(l). We need to collect the information outlined in our Technical Analysis

Plan (see Section V), so that we can assess the costs and benefits of potential fuel controls. 

This information will allow us to more accurately consider the impact of our recently

promulgated, or proposed, fuel sulfur controls and assess how toxics controls can be

incorporated. As part of the Technical Analysis Plan we will also collect information, which is

currently lacking, on the availability and feasibility of further controls and the risk posed to

public health and welfare by air toxic hot spots. Based on our conclusion that the antibacksliding controls are reasonable controls for the short-term, the fact that we lack
Response to Comments

December 20, 2000

Page 11

information suggesting further controls are appropriate in the short-term, and the fact that we

are not ready to address long-term controls in this rulemaking, we conclude that today’s antibacksliding requirement satisfies the criteria of section 202(l)(2).

Commenters are correct that this rule does not establish standards for metals. 

Metals in mobile source exhaust can come from fuel, fuel additives, engine oil additives, or

engine wear. We do not have good data about the precise sources of metals, and thus we

cannot yet target controls to reduce these emissions. Also, to the extent that metals are

present due to impurities in engine oil or from engine wear, EPA does not have clear

statutory authority to limit the metal content in oil. 

With regard to dioxin/furans, we searched available literature on the relationship

between diesel fuel and this set of air toxics. Unfortunately, there is only limited data in the

literature. Also, no standard test method is used in existing studies, and the methods that are

employed have poor accuracy. When future research clarifies this relationship, we will be

able to target emission controls and evaluate their effectiveness at reducing these emissions

and their costs.

Finally, this rulemaking does consider additional vehicle standards. Section IV of the

preamble and Chapter 6 of the Technical Support Document explain our conclusion that

additional vehichle-based controls are not warranted at this time. See also the answers to

Issue 6, below.

(C) Given the statutory requirements related to the section 202(l)(1) studies, EPA's

proposed standards are arbitrary and capricious.

(1) First, the proposal does nothing to address the significant risks found in the

studies. Thus, EPA cannot meet the statutory requirement that the rule be

"based on" the studies. Even if one assumes EPA could meet that

requirement, the commenter argues further that the studies themselves are

inadequate, which makes the rulemaking based on the studies arbitrary and

capricious. The commenter identifies a number of problems with the studies

and argues that EPA has not undertaken evaluations of health and

environmental impact as it has done in supporting other CAA regulations.

Letters:

EarthJustice Legal Defense Fund (IV-D-32) p. 1-2

Response to issue 2.1(C)(1): EPA’s 1993 study, Motor Vehicle-Related Air Toxics Study

(Report No. EPA 420-R-93-005, which can be accessed at

http://www.epa.gov/otaq/toxics.htm), was prepared pursuant to Section 202(l)(1) of the Act. 

Thus study provided estimates of motor vehicle emissions of several pollutants believed to

pose the greatest risk to public health, including benzene, formaldehyde, and 1,3-butadiene,

as required by the Act, as well as acetaldehyde, diesel particulate matter, gasoline particulate

matter, and gasoline vapors. Exposure and risk were evaluated for four different years: 

1990, 1995, 2000, and 2010. It should be noted that this study did not address whether to

promulgate air toxics standards or suggest what those standards should be. That discussion
Response to Comments

December 20, 2000

Page 12

was deferred to a future rulemaking under Section 202(l)(2). Instead, the study summarized

that was known about motor vehicle-related air toxics.

As described in the Technical Support Document for this rulemaking, we sought peer

review of this study in 1994. The comments from the peer review included suggestions for

improving EPA’s exposure modeling and risk assessment methodology. In response to

these comments, EPA updated its exposure model for motor vehicle-related air toxics. Also,

since 1993, significant new information on vehicle emission rates has been developed as

part of the Auto/Oil program, the development of the Complex Model for reformulated

gasoline, CARB test programs, and other sources, and much more is known about the

impact of fuel properties on toxic emissions. Furthermore, EPA has developed new

programs, such as the NLEV and Tier 2 standards, which have significant effects on

projections of toxic emissions and exposure. Finally, EPA has released an updated cancer

risk assessment for benzene, a draft reassessment for 1,3-butadiene, and a draft

assessment for diesel exhaust emissions. In light of this new information, and in response to

peer review comments, EPA has updated the estimates of emissions and exposure

contained in the 1993 study. The revised study, Analysis of the Impacts of Control Programs

on Motor Vehicles Toxics Emissions and Exposure in Urban Areas and Nationwide (Health

Assessment Document for Diesel (EPA 420-R-99-023/030), revises only inventory and

exposure estimates based on the new data; an updated risk analysis will be part of a

separate updated study that will be completed in connection with our Technical Analysis

Plan. We expect the revised risk estimates to be significantly different from the 1993 study

results because they will take into account the various emission control programs that have

been established since 1990.

Section 202(l)(2) instructs EPA, based on the study required under Section 202(l)(1),

to set standards for emissions of hazardous air pollutants from motor vehicles and their fuels. 

However, Section 202(l)(2) also clearly sets out the criteria that those standards must meet: 

they are to “reflect the greatest degree of emission reduction achievable through the

application of technology which will be available, taking into consideration [existing

standards] and the costs of the technology, and noise, energy, and safety factors, and lead

time.” As discussed in the preamble and Technical Support Document for this rule and

elsewhere in this Response to Comments document, we believe the standards being

finalized meet these criteria. At the same time, we considered the findings of the studies

within the context of our statutory requirements. The results of the Section 202(l)(1) studies

will also be considered in and will help inform our Technical Analysis Plan, particularly as we

evaluate the availability and costs of the technology, noise, energy, and safety factors, and

lead time of different strategies that can be applied to reduce mobile source air toxics over

and above the reductions expected by our existing and recently proposed mobile source

emission control programs.

(D) The section 202(l) studies that EPA uses as the basis for its proposal fail to

meet the statutory requirements. (See related comments under Issue 2.2(D).)

(1) The studies fail to follow established EPA risk assessment protocol. EPA

should have estimated the total risk presented by the air toxics associated

with motor vehicles (based on ambient levels) and then determined, using an

adequate margin of safety, what additional controls on motor vehicles and

fuels are necessary to address those pollutants. The Motor Vehicle Related
Response to Comments

December 20, 2000

Page 13

Air Toxics Study (April 1993) and the Estimation of Motor Vehicle Toxic

Emissions and Exposure in Selected Urban Areas (1999) were based on a

source-specific assessment, rather than on assessment of ambient levels of

hazardous pollutants, as is normally the case with such EPA risk assessment

documents as required under CAA section 202(l). EPA has failed to offer a

reasoned explanation for this departure from this holistic and scientifically

sound approach as required of it by administrative law principles which

provide that an agency may not shift its position without supplying a reasoned

explanation for the shift.

Letters:

Environmental Systems Products (IV-D-25) p. 8-9

Response to issue 2.1(D)(1): Our study followed the requirements in 202(l)(1), is consistent

with our agency guidance, and has received extensive peer review. We would also like to

point out that, unlike other provisions that the commenter may be thinking of, 202(l)(2) does

not direct EPA to set health-based standards that provide an “adequate margin of safety.” 

Instead, 202(l)(2) is a technology-based standard that directs EPA to set the standard

according to what is technologically achievable considering the criteria in 202(l)(2). 

The Agency’s 1996 proposed risk characterization guidelines

(http://www.epa.gov/ORD/WebPubs/carcinogen/) call for risk characterization to be done

based on an exposure assessment. Thus it would be inconsistent with the Agency’s own

guidelines to estimate risks based on ambient concentrations. It may be that commenter has

confused a NAAQS-type analysis with the type of analysis we usually perform for HAP

sources. In any event, the suggestion that there has been a “shift” is mistaken. 

The Agency agrees that to the extent possible, we should look at risks in the

aggregate. The National Air Toxics Assessment currently being conducted will look at

aggregate inhalation risks from outdoor sources of air toxics. We will evaluate information on

aggregate risks as part of our 2004 rulemaking.

(2) EPA's regulatory studies are inadequate because they are inconsistent with

the broad mandate of Congress to study the need for controlling MSATs

which required a study of "controlling emissions of toxic air pollutants ...

associated with motor vehicles and motor vehicle fuels." The focus of this

language is on the pollutants associated with motor vehicles, and not on the

type of vehicle. The entire inventory of these pollutants, including those from

non-road vehicles, should have been taken into account. In contrast, EPA

adopted a source-specific approach, examining the cancer risk associated

with the toxic emissions contribution of on-road motor vehicles, rather than

undertaking a comprehensive assessment of the risks of the air toxics

associated with motor vehicles, including non-road sources.

Letters:

Environmental Systems Products (IV-D-25) p. 6-7
Response to Comments

December 20, 2000

Page 14

Response to issue 2.1(D)(2): Section 202(l) directs the Agency to address emissions from

motor vehicles and motor vehicle fuels. The term motor vehicle is used in the Clean Air Act

to mean on-road motor vehicles, and thus the rule is focused on on-road vehicles, both light

and heavy duty. The Agency included a chapter to discuss the importance to nonroad

sources of emissions. See response describing legal authority under section 202(l),

response to issue 2.1(B)(1).

2.2: Adequacy of Rule to Address Public Health & Welfare Concerns

(A) Because mobile sources are the leading emissions source of HAPs in the

country, EPA must adopt more comprehensive rules than EPA has proposed.

(1) One commenter stated that EPA's listing of the top twenty sources of toxic air

emissions in the 1993 OAQPS Air Pollutant Emission Trends Report

identified on-road vehicles as the largest source, and non-road vehicles as

the fifth largest source of HAPs. Commenters also noted that the 1998

Cumulative Exposure Project (CEP) identified mobile sources as responsible

for the majority of HAP emissions, and that NESCAUM determined that

mobile sources dominate the primary emissions (40-92% of the entire

inventory for these pollutants) in all Northeastern States. Other commenters

noted that the 1996 National Toxics Inventory shows that motor vehicles and

non-road sources are responsible for 40% of all HAPs. Some of these

commenters further noted that mobile sources represented 76% and 49% of

all emissions of benzene and formaldehyde, respectively. Finally, some

commenters stated that NATA modeling showed that even small communities

significantly exceed the health benchmarks for ambient benzene

concentrations.

Letters:

Clean Air Network, et al (IV-D-38) p. 1

Commonwealth of MA DEP (IV-D-13) p. 1

Consumer Policy Institute (IV-D-8) p. 4

Environmental Systems Products (IV-D-25) p. 2-3

IL EPA (IV-D-28) p. 1

NESCAUM (IV-D-10) p. 1-2

NESCAUM (IV-F-1) p. 22-23

STAPPA, ALAPCO (IV-D-22) p. 1-2

STAPPA, ALAPCO (IV-F-1) p. 43

(2) Not surprisingly given the automobile's prevalence, motor vehicle emissions

account for up to half of all cancers attributed to outdoor sources of air toxics.

Letters:

Environmental Systems Products (IV-D-25) p. 3

Response to issues 2.2(A)(1) and (2): The Agency agrees that mobile sources are major

contributors to exposure and risk from outdoor sources of air toxics. Programs currently in
Response to Comments

December 20, 2000

Page 15

1

Federal Register 54 (177): 38044 - 38072, September 14, 1989.

place will reduce inhalation exposure to gaseous air toxics from highway mobile sources by

about 50% in 2007 and 60% in 2020, relative to 1996 levels. EPA’s 2007 standards will

reduce exposure to diesel particulate matter by over 90% by 2020. Substantial reductions in

air toxic emissions from nonroad equipment are projected as well (as described in the

preamble and Chapter 8 of the Technical Support Document). Furthermore, this rulemaking

has taken steps to ensure that reductions which have resulted from reformulation of gasoline

are maintained.

The Agency acknowledges, however, that many data gaps exist which prevent it from

fully characterizing risks. These data gaps, which include a lack of nonroad emissions data

and an inability to adequately assess the potentially disproportionate impacts of air toxics in

“hotspot” areas, are more fully described in the technical analysis plan in the preamble. As

we address these data gaps we will evaluate what additional controls may be needed to

adequately protect public health.

Finally, we would like to point out that there are no risk levels, or “benchmarks,” which

represent regulatory thresholds. However, the 1989 Benzene National Emission Standard

for Hazardous Air Pollutants (NESHAP)1

 sets an upper limit of acceptability of 1 in 10,000

lifetime cancer risk for the most exposed individual, with other health and risk factors

considered below this level to complete an overall judgement on acceptability.

(B) Because ambient concentrations of cancer-causing compounds exceed health

protective thresholds in every area of the country, EPA must adopt more

comprehensive rules than EPA has proposed.

(1) The 1998 CEP predicted that seven cancer-causing compounds exceeded

health-protective thresholds in every census tract in the country in 1990. In

the Northeast ambient concentrations of acetaldehyde, benzene, 1,3-

butadiene and formaldehyde exceed risk-screening thresholds for cancer

and, in some cases, non-cancer effects throughout the region.

Letters:

Consumer Policy Institute (IV-D-8) p. 4

Environmental Systems Products (IV-D-25) p. 2

NESCAUM (IV-D-10) p. 2

NESCAUM (IV-F-1) p. 22-23

(2) In addition to causing cancer, human exposure to these air toxics at sufficient

concentrations and durations can result in poisoning, the rapid onset of

sickness such as nausea, as well as immunological, neurological,

reproductive, developmental and respiratory problems. Hazardous air

pollutants deposited onto soil or into lakes and streams adversely affect

ecological systems and eventually harm human health through consumption

of contaminated food.
Response to Comments

December 20, 2000

Page 16

2

Federal Register 54 (177): 38044 - 38072, September 14, 1989.

Letters:

Environmental Systems Products (IV-D-25) p. 2-3

Response to issues 2.2(B)(1) and (2): We agree that at certain exposure concentrations

some HAPs may cause a variety of cancer and non-cancer health effects. We also agree

with the commenter that, to the extent possible, future risk analyses should consider more

than just the cancer risk associated with inhalation exposure. Chapter 3 of our TSD describes

the potential health effects associated with each MSAT and the various exposure routes of

concern. 

Average nationwide exposures to benzene and formaldehyde exceed concentrations

which would result in a one in a million upper bound lifetime risk, and in many areas of the

country, exposure concentrations exceed one in a hundred thousand upper bound lifetime

risk levels. A one in a million lifetime cancer risk level represents an annual risk of about 1.4

in 100 million, or about 3.5 cancer incidences in the entire U.S. population. 

The EPA unit risk estimate for 1,3-butadiene is expected to be revised downward

substantially as a result of a reassessment which is nearing completion. As a result, it is

unlikely that average nationwide exposures will still exceed a one in a million upper bound

lifetime risk.

Draft concentration results from the National Air Toxics Assessment (NATA) suggest

that exposures to acrolein in many areas of the country may exceed the reference

concentration, or RfC. In a few areas of the country, exposures to formaldehyde and

acetaldehyde may also exceed the RfC. The RfC is an estimate (with uncertainty spanning

perhaps an order of magnitude) of a continuous inhalation exposure to the human population

(including sensitive subgroups) that is likely to be without an appreciable risk of deleterious

effects during a lifetime. It can be derived from various types of human or animal data, with

uncertainty factors generally applied to reflect limitations of the data used. Exposures above

the RfC are not necessarily harmful, but indicate a potential for adverse health effects.

Although there are no risk levels which represent regulatory thresholds, the 1989

Benzene National Emission Standard for Hazardous Air Pollutants (NESHAP)2

 sets an upper

limit of acceptability of 1 in 10,000 lifetime cancer risk for the most exposed individual, with

other health and risk factors considered below this level to complete an overall judgement on

acceptability. Available exposure assessment tools estimate population exposures rather

than the exposures experienced by the most exposed individuals. They lack the level of

refinement which would enable us to adequately assess the highest exposures found in

mobile source “hotspots.” The Technical Analysis Plan described in the preamble of the rule

discusses our plan for better characterizing “hotspot” exposures.

(C) While potentially supporting an anti-backsliding provision, the proposal is

inadequate as the sole regulation on air toxics to be proposed at this time.
Response to Comments

December 20, 2000

Page 17

(1) Commenters argue that EPA cannot just rely on other criteria pollutant rules,

especially because the turnover is too long. One of the commenters noted

that even under the best of circumstances, the proposed program will not

afford additional controls on any emissions of mobile source air toxics for at

least six or seven years, an unacceptably long time. Another commenter

argued that EPA cannot rely on vehicle fleet turnover to achieve emission

reductions of MSATs because fleet turnover is gradual and because the new

technology needed to meet the new standards is unproven and prone to

malfunction. This commenter also pointed out that the NAAQS control

measures relied upon by EPA for a continuing reduction in mobile source

toxic emissions are not all nationwide programs (while air toxics are a

nationwide problem). Also, these programs are not all permanent and EPA

has failed to address the potential for future relaxation of standards designed

for attainment purposes that may not be needed in the future. Commenter

urges EPA to adopt a strong nationwide I/M program as the most costeffective means of reducing air pollutant emissions.

Letters:

Clean Air Network, et al (IV-D-38) p. 1-3

Environmental Systems Products (IV-D-25) p. 13-16

Environmental Systems Products (IV-F-1) p. 53-57

Puget Sound Clean Air Agency (IV-D-27) p. 1

STAPPA, ALAPCO (IV-D-22) p. 2

STAPPA, ALAPCO (IV-F-1) p. 44-45

Response to issue 2.2(C)(1): EPA acknowledges that standards placed upon new motor

vehicles do not result in immediate emission reductions because of the practical and

statutory need to provide industry with reasonable lead time to implement the controls and

the unavoidable fact that motor vehicle fleet turnover is gradual. Unfortunately, this is an

inherent limitation of all standards for new vehicles, whether they are designed to address

criteria pollutants or air toxics.

EPA’s current and proposed vehicle standards will address gaseous and particulate

toxics just as well as non-toxic VOCs and PM. More stringent controls, either in terms of

shorter lead time or tighter standards, are not achievable.

For fuel controls, lead time is also an issue. Our anti-backsliding program can be

implemented with almost no lead time. As described in Section IV of the preamble and

Chapter 6 of the Technical Support Document for this rule, we have determined that

additional near term controls are not reasonable. We will continue to analyze log-term

controls to determine what is controls are appropriate.

The Agency agrees with the comment that not all NAAQS-based programs are

national in scope (e.g., RFG) nor are all criteria pollutant measures permanent (e.g., some

local controls). The rule is designed to avoid future increases in air toxics across the nation. 

See response to issue 5(C) for a discussion of I/M programs.
Response to Comments

December 20, 2000

Page 18

(2) The proposed benzene emissions standards are not sufficient to protect

public health, and should be set at a lower level. Instead of merely codifying

existing benzene levels, EPA should establish a nationwide fuel benzene cap

that is more stringent than the 1.0 percent cap under the Phase I RFG

program. Commenters added that the cap also should be no higher than the

lowest benzene level currently being achieved in the U.S. today. This cap

should be as low as feasible and should apply nationally. Another

commenter argued that, given the known health and environmental impacts of

benzene, EPA should ratchet down emissions below levels currently achieved

by refiners. Another commenter stated that, at the very least, EPA should

extend the RFG program's benzene cap to all gasoline. This commenter

added that by locking in benzene at baseline levels, EPA is establishing

regional standards, rather than a protective nationwide standard, which will

force those living in areas with a higher than average benzene content to

continue to bear this health burden. EPA needs to take more aggressive

action in terms of standards and timing to address public health concerns. 

Letters:

Commonwealth of MA DEP (IV-D-13) p. 2

Consumer Policy Institute (IV-D-8) p. 4

NESCAUM (IV-D-10) p. 6

NESCAUM (IV-F-1) p. 23-24

Oregon Environmental Council (IV-D-9) p. 1

STAPPA, ALAPCO (IV-D-22) p. 3

Response to issue 2.2(C)(2): Unlike other provisions of the Act, section 202(l)(2) does not

direct EPA to set standards to eliminate or achieve a certain level of risk. Section 202(l)(2)

directs to address pollutants that pose a health concern and impose standards that are the

most stringent feasible within the “technology-based” criteria described in the provision. As

discussed previously, programs currently in place will result in substantial reductions in

benzene and other hazardous air pollutants. In 2004, we will determine whether additional

fuel controls, or emission standards for highway vehicles and nonroad engines, are

appropriate under the Act. EPA regulations are not designed to eliminate risk, nor to achieve

a certain level of risk. They are intended to address pollutants that pose a health concern

and impose standards that are the most stringent feasible within criteria described in the

relevant statutory provision. As discussed previously, programs currently in place will result

in substantial reductions in benzene and other hazardous air pollutants. In 2004, we will

determine whether additional fuel controls, or emission standards for highway vehicles and

nonroad engines, are needed to protect public health.

(3) EPA should impose a nationwide limit that reflects the in-use benzene levels

in RFG areas and apply the RFG area benzene limits to non-RFG areas. 

This could reduce by half the present benzene levels in non-RFG areas and

maintain existing benefits in RFG areas. A single nationwide limit would also

be enforceable throughout the gasoline distribution system with minimum

recordkeeping and other administrative requirements. Another commenter

stated that EPA should acknowledge that the current proposed rule is but the

first step on benzene and should include a provision to revisit the issue by the
Response to Comments

December 20, 2000

Page 19

end of 2001 and explore the need for a nationwide benzene cap. Otherwise,

non-RFG areas will continue to experience elevated benzene levels. One

commenter in hearing testimony generally argued for nationwide standards to

address non-RFG areas.

Letters:

California Air Resources Board (IV-D-1) p. 2

Clean Air Network, et al (IV-D-38) p. 3-4

Michigan Environmental Council (IV-F-1) p. 67-71

Response to issue 2.2(C)(3): Section 202(l)(2) requires EPA to adopt regulations that

contain standards which reflect the greatest degree of emissions reductions achievable

through the application of technology that will be available, taking into consideration existing

motor vehicle standards, the availability and costs of the technology, and noise, energy and

safety factors. Today’s rule adopts an anti-backsliding requirement that EPA believes is

appropriate under section 202(l)(2) as a near-term control. We are not adopting long-term

controls such as uniform national gasoline air toxics limits because we lack the information

necessary to assess appropriate long-term controls.

Today’s rule addresses toxics emissions from fuels in the near-term. The rule will

cap the toxics performance levels of gasoline beginning in 2002. Adopting an antibacksliding program is a reasonable control on toxics emissions from fuels. The technology

to maintain the current toxics performance of gasoline produced at each refinery is already

available and continued compliance will not be costly even with implementation of our

recently adopted sulfur controls (see discussion in section V, and in chapter 7 of the technical

support document). 

We do not believe, however, that we could reasonably adopt further controls in this

near-term time frame. First, the lead time is too short to allow for investments and upgrading

of refinery equipment in any significant manner. For example, not all refiners produce

benzene at the national average level and also because they do not currently use the same

production techniques and so therefore cannot use the same or similar strategies to achieve

the national average level of benzene fuel content. Second, we have recently adopted, or

proposed to adopt, two regulations that will achieve very significant emissions reductions by

setting tight limits on the sulfur content of fuels used in on-highway vehicles. To comply with

these new regulations, industry is already planning and investing in capital improvements and

pursuing the necessary permitting to upgrade their refineries. While we lack the information

to fully assess the costs and benefits of further controls in the 2002 time frame, we have

serious concerns that further toxics controls in the 2002 time frame could interfere with

refiners’ planning and affect their ability to meet our recently promulgated, or proposed, sulfur

standards.

Even though today’s rule focuses on near-term options for controlling toxic emissions

from fuels, we plan to address the appropriateness of long-term controls in our future

rulemaking. We are not ready, however, to address these long-term controls in this

rulemaking. We need to collect the information outlined in our Technical Analysis Plan (see

Section V), so that we can assess the costs and benefits of potential fuel controls. This

information will allow us to more accurately consider the impact of our recently promulgated,
Response to Comments

December 20, 2000

Page 20

or proposed, fuel sulfur controls and assess how toxics controls can be incorporated. As part

of the Technical Analysis Plan we will also collect information, which is currently lacking, on

the availability and feasibility of further controls and the risk posed to public health and

welfare by air toxic hot spots. 

(4) Even if the controls EPA is relying upon to address mobile source air toxics

do result in a seventy-five percent reduction in certain pollutants, as EPA

claims, that may still not be enough. One of these commenters added that

the measure of successful regulation of hazardous air pollutants, according to

EPA practice in other rules and as interpreted by the court in the 1994

decision related to the benzene NESHAP, is the reduction in the risk to public

health to as close to one in one million as possible. In hearing testimony, one

commenter also stated that the 1 in 100,000 or 1 in 1,000,000 thresholds

were appropriate indicators of unacceptable risk.

Letters:

Commonwealth of MA DEP (IV-D-13) p. 1

NESCAUM (IV-F-1) p. 31

STAPPA, ALAPCO (IV-D-22) p. 2

STAPPA, ALAPCO (IV-F-1) p. 45-46

Response to issue 2.2(C)(4): The Agency agrees with the commenter that the expected

significant reductions in mobile source air toxic emissions from 1990/ 96 to 2020 may not be

sufficient to fully protect public health and welfare. One of the missing pieces of information

is hot spot exposures which the Agency has committed to explore in the future. The risk

targets for other program that are identified by commenters, while desirable goals in general,

are not necessarily relevant here where the statute requires a technology-based approach

even for emissions of toxics. EPA must evaluate the appropriateness of its controls

according to the criteria in section 202(l)(2).

(D) EPA's methodologies to evaluate health risk are not protective and distort the risk in

most urban areas.

(1) One of the commenters argued that the CAA requires EPA to establish

standards with an adequate margin of safety for special populations such as

children and those with compromised health. In addition, commenters stated

that the study methodology contained a number of problems; commenters

raised some or all of the following: EPA failed to evaluate health risks in

urban areas; EPA failed to evaluate cumulative exposure to respiratory

irritants; EPA has not considered "hotspots" of exposure; middle income

Caucasians do not represent those most exposed; in the absence of data

about particular microenvironments, EPA should assume ambient prevalent

concentrations for 24 hour/7 day a week exposure; EPA has not established

that carbon monoxide exposure is a good indicator for estimating toxics

exposures; EPA should be very concerned about the 30% underestimate of

ambient concentrations at the highest percentile of population exposure; and

the NATA assessment should assess more pathways than inhalation risks. 

As further documentation of these concerns, one of the commenters attached
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December 20, 2000

Page 21

(and provided a brief summary of ) the 1999 NESCAUM Peer Review of the

U.S. EPA's DRAFT Estimation of Motor Vehicle Toxic Emissions and

Exposure in Selected Urban Areas (October 1999). The commenter also

attaches a chart to show how the approach taken in the section 202(l) studies

differs from other EPA regulatory actions. Another commenter also cites to

NESCAUM's critique, and also notes that the studies relied on by EPA do not

properly account for either cumulative risk or emissions from non-road motor

vehicles. The commenter argues that these types of deficiencies cause EPA

to underestimate the dangers to the public posed by MSATs.

Letters:

Consumer Policy Institute (IV-D-8) p. 5

NESCAUM (IV-D-10) p. 9

Response to issue 2.2(D)(1): The Agency does not dispute the fact that the area of risk

assessment for air toxics is an evolving area of research. The commenter’s litany of

shortcomings in the Agency’s assessment capabilities identifies some areas where the

Agency has been working to make improvements, as well as some areas that need

additional improvement. In this case, the Agency’s action is based on the best information

available at this time. For the record, there has been significant progress over the last

decade in our understanding of adverse health effects related to air toxics. For example, the

1999 mobile source air toxics study contained superior modeling of urban air toxic emissions

and exposure concentrations due to extensive modeling of fuel properties within 10

metropolitan area across the nation. One limitation of the 1999 study was its reliance on

carbon monoxide personal exposures as a surrogate for air toxic exposures. Although CO is

a reasonable surrogate for exposure to toxics emissions, it is less reliable for more

photochemically reactive compounds than those that are relatively inert. The next generation

exposure model no longer relies on a CO-surrogate methodology. Instead of using direct CO

measurements as surrogates to model toxics exposures, it uses modeled toxics

concentrations as input. Although using modeled data instead of direct measurements as

input has its own inherent limitations, we believe this change represents an improvement for

most applications. The database of human activity diaries has been substantially improved

with thousands of additional entries, although results of sensitivity analyses indicate that had

the more extensive activity database been available when the exposure modeling was done,

it would have had a minimal impact on the results. In other areas, such as hot spots or

cumulative exposures, the Agency will continue to commit resources to further research.

(2) Commenters provided detailed criticism of the use of the Hazardous Air

Pollutant Exposure Model to support this rulemaking. Commenters

challenged a number of specific elements of these models, including that the

models: rely on limited time-activity diary data; do not account for the

evaporative loss of benzene; assume toxic concentrations are proportional to

the carbon monoxide concentration; assume an average ambient

concentration for carbon monoxide over a 50 km study area; do not justify

microenvironmental factors; do not provide ranges for average exposure

estimates; do not estimate exposure for the upper 10% of the population; do

not adequately represent the variance in the population exposures; have no

input parameters available for public review; and are too complicated for
Response to Comments

December 20, 2000

Page 22

interested parties to evaluate the model predictions more thoroughly. In

hearing testimony, one commenter stated that non-road emissions will be an

increasing problem and the lack of consideration of non-road sources was a

significant problem in this study. 

Letters:

Environmental Systems Products (IV-D-25) p. 9-11

NESCAUM (IV-D-10) p. 12-13

NESCAUM (IV-F-1) p. 24, 27-30

Response to issue 2.2(D)(2): We agree that, to the extent possible, cumulative risks across

source categories and pollutants should be addressed in a risk characterization, including

multiple pathways of exposure. The Technical Support Document for this rule includes a

review of available ambient concentration and exposure data. It also identifies significant

limitations associated with available tools and methods. Despite limitations in these tools

and methods, they are useful in helping the Agency develop priorities for research and

regulatory evaluations.

We would like to note that EPA has assessed population exposures in urban areas,

although the tools currently available lack the refinement to estimate individual exposures in

urban “hotspots.” Furthermore, the model is designed to estimate average population

exposures, and the Agency believes it is less accurate at the low and high end of the

exposure distribution. Although one commenter recommended using ambient concentrations

rather than exposure estimates to characterize risk, such an approach would be inconsistent

with the Agency’s own risk assessment guidelines (available at www.epa.gov/ncea ). 

Ambient concentrations do not take into account differences in concentration levels within

different microenvironments, or time people spend in these microenvironments.

The Technical Support Document for this rule presents on-highway mobile source

exposure estimates developed using the Hazardous Air Pollutant Exposure Model for Mobile

Sources, version 3 (HAPEM-MS3). All input parameters used in the model are publicly

available. This model uses CO as a tracer for toxics. Since most ambient CO comes from

cars and light trucks, we believe CO exposure is a reasonable surrogate for exposure to

toxics emissions. Since carbon monoxide is relatively inert, and some modeled compounds

are photochemically reactive, we adjusted results to account for differences in photochemical

reactivity. 

The model simulates the movement of individuals between home and work and

through a number of different micro-environments. Activity data used in the model were

obtained from a three-city database which included about 3600 person days of data from 23

demographic groups, including African Americans and Hispanic Americans, not just

Caucasians as stated by one commenter. However, data for non-English speaking

demographic groups are limited.

The CO concentration in each micro-environment is determined by multiplying the

ambient concentration by a micro-environmental factor. Ambient concentrations are obtained

from monitor data, with urban areas divided into 20km districts around each monitor, not

50km as one commenter stated. The microenvironmental factors were derived using paired
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December 20, 2000

Page 23

ambient and personal exposure monitor measurements from CO studies in Denver and

Washington. Modeled CO exposure attributable to on-highway vehicle emissions for 1990

was divided by 1990 CO grams per mile emission estimates to create a conversion factor. 

The conversion factor was applied to modeled toxic emission estimates (in grams per mile) to

determine exposure to on-highway vehicle toxic emissions. The modeling approach

accounts for evaporative benzene emissions, but does not account for differences in spatial

and temporal distributions of benzene evaporative emissions relative to benzene exhaust

emissions. The modeling also does not account for exposures to benzene emissions

originating in attached residential garages. These exposures may be significant, as

discussed in the Technical Support Document. Comparison of HAPEM-MS3 based

estimates of exposure to other available data sources suggest that the HAPEM-MS3

approach provides reasonable estimates of inhalation exposure.

The NATA National Scale Analysis will address cancer and noncancer inhalation risk

from all outdoor sources, assuming lifetime population exposure to 1996 levels. It also

addresses some of the limitations identified in the HAPEM-MS3 exposure methodology. For

instance, it estimates exposure based on modeled toxics concentrations, rather than relying

on the CO tracer approach described above. This assessment will include more extensive

time activity data than in previous exposure assessments done by the Office of

Transportation and Air Quality. Moreover, it will address non-cancer health endpoints across

pollutants for specific target organs and organ systems. This includes respiratory effects. 

It should be noted that the model cannot estimate individual exposures. The data are

also still limited for non-English speaking demographic groups. Moreover, the National Scale

Analysis will not include risks from indoor sources or non-inhalation pathways. The Agency

does not currently have the tools to conduct a comprehensive multimedia assessment that

includes indoor and outdoor sources. In addition, the National Scale Analysis will not

account for substantial reductions in risk as a result of current and future mobile source

control programs.

The purpose of this assessment is to help identify pollutants of greatest potential

concern, and to set priorities for collection of additional air toxics data to improve future

assessments. It is not designed to characterize risks sufficiently for regulatory action. 

(3) In addition to the problems identified in the methodology, commenters also

argued that the risk characterization and management methodology

conducted under the proposed regulation is not consistent with Agency

practice.

Letters:

Environmental Systems Products (IV-D-25) p. 1-2

NESCAUM (IV-D-10) p. 9-10, att.

Response to issue 2.2(D)(3): The commenter would like the Agency to use the regulatory

approach typically used when promulgating rules based on attainment and maintenance of

an established NAAQS. In NAAQS-based rulemakings, the Agency develops national and

regional emissions inventories and forecasts future ambient concentrations of air pollution of

concern across the nation. For the populations that live i areas with projected concentrations
Response to Comments

December 20, 2000

Page 24

above the relevant NAAQS, there is a reasonable risk of adverse health effects. This forms

that basis of a NAAQS-based rulemaking. 

The commenter would like the Agency to use the 10-6 risk level as a de facto

NAAQS. However, in the case of air toxics there are no agreed-upon health based standards

for ambient concentrations. An exposure model called HAPEM is used to translate ambient

concentrations into risk levels. This additional step is made necessary by the lack of a

standard for determining that ambient concentrations place the population exposed to them

at risk. 

Section 202(l)(2), however, does not establish this kind of health- or risk-based

scheme. Instead we are directed to address those emissions causing or contributing to air

pollution problems by adopting controls meeting the technology-based “achievability” criteria

in section 202(l)(2).

(E) EPA fails to clearly describe what it believes the framework to construct a

national MSAT program is or should be.

(1) Instead the NPRM describes what existing programs, not designed for toxics,

are expected to do. EPA also fails to describe what it will do between now

and 2004 to develop the 2004 proposal. Clearer descriptions are necessary

for adequate comment on the NPRM.

Letters:

Consumer Policy Institute (IV-D-8) p. 2

Response to issue 2.2(E)(1): As stated previously, the Agency acknowledges the fact that

the science of risk assessment for air toxics is evolving. The contribution from this

rulemaking is to identify and describe existing data gaps for future research. The

development of a framework for a national MSAT program will grow out of the workshops

and research agenda articulated in the rule. Interested readers should refer to our

description of the Technical Analysis Plan in the preamble for this rule, which contains

additional details.

2.3: Environmental Justice Concerns 

(A) Commenter supports EPA's plans to address "hotspots" in low income and

minority communities.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Oregon Environmental Council (IV-D-9) p. 1

Response to issue 2.3(A)(1): Several commenters expressed general support for our plan

to address “hot spots” in low income and minority communities. As noted in the preamble for

this rulemaking, the NATA National Scale Analysis reports distributions of concentrations
Response to Comments

December 20, 2000

Page 25

across census tracts nationally and at the county level. While providing a significant and

informative body of information, these studies do not address exposures to toxics in hot spot

areas. As the Agency has stated in the Integrated Urban Air Toxics Strategy, we also want to

consider the disproportionate impacts of air toxics in hot spot areas. Hot spots are generally

thought of as areas with elevated pollutant levels that could be associated with elevated

exposures and potentially serious health risks. At higher pollutant concentrations, the

potential for risk increases, making it important to characterize the distribution of exposure in

the population. States and local air pollution control agencies have raised the hot spots issue

as a major concern that needs to be addressed in a comprehensive air toxics risk

characterization.

To improve our ability to characterize MSAT exposures to highly exposed

subpopulations requires better information regarding ambient concentrations of MSATs in hot

spot areas and appropriate microenvironmental factor values for high-exposure

microenvironments. As part described in our discussion of the Technical Analysis Plan in the

preamble for this rule, EPA is developing local-scale emissions and dispersion models for

mobile sources to better inform the Agency and the public about potential hot spots. In

addition, EPA is conducting spatially refined urban area modeling (including mobile sources).

(B) The proposal fails to adequately address the issue of environmental justice.

(1) The proposal cannot meet the requirements of the President's Executive

Order on Environmental Justice. EPA must construct a national MSAT

program that protects those most exposed to unacceptably high

concentrations of mobile source emissions.

Letters:

Consumer Policy Institute (IV-D-8) p. 5

(2) Commenter provides no further supporting information or detailed analysis.

Letters:

EarthJustice Legal Defense Fund (IV-D-32) p. 2

Response to issues 2.3(B)(1) and (2): Executive Order 12898, Federal Actions to Address

Environmental Justice in Minority Populations and Low-Income Populations, is intended to

focus federal attention on the environmental and human health conditions of minority and

low-income populations with the goal of achieving environmental protection for all

communities. The Order directs federal agencies to develop environmental justice strategies

to aid federal identify and address disproportionately high and adverse human health or

environmental effects of their programs, policies, and activities on minority and low-income

populations. The Order is also intended to promote nondiscrimination in federal programs

substantially affecting human health and the environment, and to provide minority and

low-income communities access to public information on, and an opportunity for public

participation in, matters relating to human health or the environment. The Presidential 

Memorandum accompanying the Order underscores certain provisions of existing law that
Response to Comments

December 20, 2000

Page 26

can help ensure that all communities and persons across this nation live in a safe and

healthful environment. 

One of the provisions of the Executive established an Interagency Working Group

(IWG) on environmental justice chaired by the EPA Administrator and comprised of the

heads of eleven departments/agencies and several White House offices. EPA has also

developed a strategy to address environmental justice. The strategy contains five major

areas with include: 1) Public Participation and Accountability, Partnerships, Outreach, and

Communication with Stakeholders; 2) Health and Environmental Research; 3) Data

Collection, Analysis, and Stakeholder Access to Public Information; 4 American Indian and

Indigenous Environmental Protection; and 5) Enforcement, Compliance Assurance, and

Regulatory Reviews. 

The program established in this rule conforms with the requirements of the

Environmental Justice executive order. By setting new gasoline toxics performance

standards for a broad set of gaseous toxics that ratchet down existing requirements, we

ensure that emissions performance will not deteriorate below today’s levels in all areas as

well as in minority and low-income communities. In addition, as described in the response to

issue 2.3(A)(1) above, the Technical Analysis Plan described in the preamble for this rule

contains a plan to address more carefully urban hotspots and air toxics exposure for sensitive

subpopulations.

2.4: Consistency with Integrated Urban Air Toxics Strategy 

(A) The failure to substantively and comprehensively address MSATs in the

proposed rule is contrary to EPA's Integrated Urban Air Toxics Strategy

(IUATS).

(1) The Agency has spoken extensively and for years about the contribution of

mobile sources to air toxics, particularly when trying to justify not placing

additional controls on sources of air toxics, like area sources. The Urban Air

Toxics Strategy is a prime example of this. The Agency is playing a

dangerous shell game by promising to address air toxics including mobile

sources and then failing to put forward a mobile source toxics strategy that

meets that commitment. The danger lies in allowing the public to continue to

be exposed to air pollutants many times health based thresholds for many

years to come. For the Urban Air Toxics Strategy to succeed, EPA must

address mobile source air toxics.

Letters:

Consumer Policy Institute (IV-D-8) p. 2

Puget Sound Clean Air Agency (IV-D-27) p. 1-2

Response to issue 2.4(A)(1): As explained in greater detail in the Technical Support

Document for this rulemaking, the Integrated Urban Air Toxics Strategy (IUATS) has three

primary goals:
Response to Comments

December 20, 2000

Page 27

& Attain a 75-percent from reduction from 1990 levels in the incidence of cancer

attributable to exposure to HAPs emitted by stationary sources

& Attain a substantial reduction from 1990 levels in public health risks posed by

emissions from area sources

& Address disproportionate impacts of air toxics hazards across urban areas

The third goal will involve consideration of both stationary and mobile source

emissions of HAPs, as well as sources of HAPs in indoor air. Today’s rule fits into the IUATS

in that it provides the mobile source component of the Agency’s program to reduce air toxics

emissions from mobile sources. The standards being finalized are intended to maintain

current levels of over-compliance with gasoline toxics performance requirements under the

federal reformulated gasoline and anti-dumping programs, thus ensuring that the toxics

emissions performance of gasoline does not deteriorate. With regard to additional controls,

the Agency is not engaged in a “shell game” to defer action on mobile source air toxics to the

IUATS. Instead, the preamble for this rulemaking includes a description of a Technical

Analysis Plan that we will implement to obtain the information we need to assess the need for

and feasibility of additional control measures that may reduce exposure to mobile source air

toxics even more, both for the general population and for sensitive populations or those living

in “hot spot” areas.

With regard to the continuing exposure to mobile source air toxics, as explained in

the preamble and Technical Support Document for this rulemaking, inventories of onhighway vehicle air toxics are expected to decline substantially over the next 20 years as a

result of emission control programs that were put in place primarily to reduce ambient

concentrations of criteria pollutants through volatile organic compound (VOC), carbon

monoxide (CO) and particulate matter (PM) controls. By 2020, these programs are expected

to reduce the levels of on-highway emissions of benzene by 73 percent, formaldehyde by 76

percent, 1,3-butadiene by 72 percent, and acetaldehyde by 67 percent from 1990 levels. In

addition, by 2020, we expect to see on-highway diesel PM emission reductions of 94 percent

from 1990 levels. The reductions expected from our existing nonroad control programs are

also expected to be significant, although not as substantial as the reductions for on-highway

vehicles. Consequently, public exposure to mobile source air toxics is expected to decline

substantially over the next 20 years.

(2) One commenter argued that the IUATS deferred risk characterization and

emission reduction goals to the section 202(l) rulemaking. EPA needs to

clarify how the proposal addresses the risk reduction goals of the IUATS

when it addresses only benzene and does not seek any emission reductions. 

Moreover, this and another commenter noted that the IUATS commits EPA to

consider cumulative risks presented by exposure to HAPs, but the studies

relied on in the section 202(l) rulemaking use a narrow evaluation of the

average, population-based, risk contribution of on-road sources.

Letters:

Environmental Systems Products (IV-D-25) p. 8

NESCAUM (IV-D-10) p. 9-10
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December 20, 2000

Page 28

NESCAUM (IV-F-1) p. 26-28

Response to issue 2.4(A)(2): See response to 2.4.A(1), above. While this rule does not

contain specific emission control programs that reduce exposure and risk from mobile source

air toxics, and instead seeks to maintain over-compliance with the federal reformulated

gasoline and anti-dumping programs, it nevertheless addresses the risk reduction goals of

the IUATS. First, it estimates the reductions in mobile source air toxics inventories that are

associated with current mobile source programs that were put in place primarily to reduce

ambient concentrations of criteria pollutants. This information will be used in our upcoming

risk analysis study, to be completed as part of our Technical Analysis Plan. Second, the rule

identifies the data gaps that must be filled to perform a more comprehensive analysis of

mobile source air toxics control measures. This includes information about the effectiveness

and costs of vehicle, fuel, and nonroad controls as well as about exposure and risk for

sensitive subpopulations, the range of total public exposure to air toxics, and the inventory

impacts of nonroad sources. We will collect information about these issues as part of the

Technical Analysis Plan we will implement as described in Section VII of the preamble for

this rule and will use this information in a future mobile source air toxics rulemaking to be

completed no later than July 1, 2004. These three activities, the risk analysis, Technical

Analysis Plan, and future rulemaking, further our progress toward the goals of the IUATS.

EPA will also be looking at cumulative risk as part of our IUATS and National Air

Toxics Assessment activities as well as through our Technical Analysis Plan.
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December 20, 2000

Page 29

ISSUE 3: DESIGNATION OF MSATS

3.1: General Comments on MSAT List

(A) Generally supports the proposed MSAT list.

(1) Commenter notes that the listing process may move EPA to monitor the listed

pollutants more closely in urban and surrounding areas.

Letters:

Clean Air Network, et al (IV-D-38) p. 2

Response to issue 3.1(A)(1): We will continue to focus toxics monitoring on pollutants that

current information suggests may pose the greatest risk based on the quantity of emissions

in urban and surrounding areas. Specific studies designed to assess the potential health

effects associated with exposure in mobile source hotspots will include an assessment of the

MSATs to the degree possible. 

(B) Mobile Source Air Toxics (MSAT) should be changed to Mobile Source HAPS

(or MSHAPS) to better convey that these chemicals have the potential to be

toxic (i.e., cause harm) but only at high enough concentrations at long enough

exposures.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Koch Petroleum Group (IV-D-36) p. 2

Response to issue 3.1(B)(1): We disagree that the MSATs should be renamed to convey

an understanding of potential to cause harm. The compounds on the MSAT list were not

chosen based on the potential risk associated with exposure to these compounds. Inclusion

of a compound on the MSAT list does not constitute a determination by EPA that emissions

of the compound in fact present a risk to public health or welfare, or that it is appropriate to

adopt controls to limit the emissions of such a compound from motor vehicles or their fuels. 

The purpose of the list is to provide a screening tool that identifies those compounds emitted

from motor vehicles or their fuels for which further evaluation of emissions controls is

appropriate. In conducting any such further evaluation, pursuant to sections 202(a) or 211(c)

of the Act, EPA would consider whether emissions of the compound cause or contribute to air

pollution which may reasonably be anticipated to endanger public health or welfare. Such an

evaluation would also consider the appropriate level of any controls, based on the criteria

established in section 202(l)(2). Inclusion of a compound on the MSAT list does not decide

these issues, but instead identifies those compounds for which such an evaluation would

appear to be warranted.

(C) An independent third party review should be conducted by EPA of the Mobile

Source Air Toxics (MSAT) list of compounds.
Response to Comments

December 20, 2000

Page 30

(1) Commenter questions the selection of some of the compounds EPA has

identified as MSATs, in particular the commenter does not believe diesel

exhaust is appropriate for inclusion in the MSAT list. The commenter

discusses the ability of the Health Effects Institute (HEI) to conduct health

effects testing on specific compounds of interest as well as their ability to

assist the Agency in assessing which pollutants might be of pubic health

concern.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 2

Response to issue 3.3(C)(1): We have and will continue to invite comment and review of

our Mobile Source Air Toxics list as new information becomes available. We are actively

engaged with HEI in setting priorities and directions for work funded through this

organization. Research funded through HEI is used by EPA in determining the cancer and

noncancer health effects of the compounds listed in the Integrated Risk Information System

that EPA uses in the approach to list MSAT. The specific issue of inclusion of diesel exhaust

in our list of MSAT is addressed under the response to comment on issue 3.3.3 (B)(1)

through 3.3.3 (B)(5).

3.2: Methodology for Identifying MSATs

(A) MSATs should not be limited to those compounds identified on the Integrated

Risk Information System (IRIS).

(1) EPA should use emission speciation profiles as the primary data source used

to list a MSAT. Commenter notes several reports on toxic compounds other

than IRIS that could be used to flesh out EPA's MSAT list.

Letters:

NESCAUM (IV-D-10) p. 4-6

Response to issue 3.2(A)(1): Since the MSAT list specifically identifies those compounds

that have the potential to cause a serious health effect, we cannot rely solely on emission

speciation profiles as the primary source of data to list a compound as an MSAT. The

Agency has established IRIS as the clearinghouse for all Agency consensus information

related to the potential cancer and noncancer health effects of individual compounds. While

other databases exist that report potential toxic effects of specific compounds, the review

process for these databases is not consistent with that for IRIS.

3.3: Compounds on MSAT List

3.3.1: Specific Pollutants to Exclude from List 

(A) Commenter proposes that lead, manganese or manganese compounds,

dioxin/furan, arsenic compounds, chromium compounds, mercury compounds,
Response to Comments

December 20, 2000

Page 31

3

Ball, James C. (1997) Emission Rates and Elemental Composition of Particles

Collected from 1995 Ford Vehicles Using the Urban Dynamometer Driving Schedule, the

Highway Fuel Economy Test, an the US06 Driving Cycle. Society of Automotive Engineers,

SAW paper No. 97Fl-376.

4

EPA (1993) Volatile Organic Compound (VOC) / Particulate Matter (PM) Speciation

Data System (SPECIATE), Version 1.5. http://www.epa.gov/ttn/chief/software.html#speciate.

Arsenic is found in profiles 32102 and 32103, for light duty diesel vehicles. These data were

originally from the PM10 Source Composition Library for the South Coast Air Basin,

Prepared by NEA, Inc., July 15, 1987.

and nickel compounds be removed from the list because they are either already

regulated by EPA or they do not occur in high enough levels.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Koch Petroleum Group (IV-D-36) p. 2-3

Response to issue 3.3.1(A)(1): See response under 3.3.1(C)(1) below.

(B) Arsenic should not be included on the list at least with respect to on-road

sources.

(1) Arsenic is not found in the exhaust of modern gasoline-fueled vehicles. 

However, commenter notes that it may be emitted by non-road and aircraft

sources. Commenter cites an SAE report that arsenic was found to be not

significantly greater than zero in 1995 Ford vehicle tests. Commenter

recommends that the Draft Support Document indicate that arsenic was

below the limits of detection.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 3

Response to issue 3.3.1(B)(1): While in the speciation study to which the commenter

refers,3

 arsenic was not found in motor vehicle exhaust at levels above the method detection

limit, we include arsenic on the motor vehicle list of MSATs due to the presence of this

element in the SPECIATE database for motor vehicle emissions.4

 Updates to the SPECIATE

database are planned for the future which may change the listing of some compounds,

including arsenic. When we re-open the rulemaking in 2003 any changes to the SPECIATE

database will be used to revise the MSAT list as required.

(C) N-hexane has little or no inherent activity and should not be included on the

list.
Response to Comments

December 20, 2000

Page 32

(1) The health effects of n-hexane are only at very high concentrations, and it is

likely that n-hexane at ambient concentrations has no effects on any

organism.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 3

Response to issue 3.3.1(A)(1) and (C)(1): As explained above, our approach for listing a

compound as an MSAT is based on the presence (not the quantity of emissions) of the

compound in the emissions from motor vehicles or their fuels and an Agency consensus

view, as expressed on IRIS, that the compound has the potential to cause serious adverse

health effects. In keeping with this approach, we will maintain n-hexane, lead compounds,

manganese compounds, dioxin/furan, arsenic compounds, chromium compounds, mercury

compounds, and nickel compounds on our list of MSATs. As discussed above, it should be

noted that inclusion of these compounds on the MSAT list is not itself a determination by

EPA that environmental exposures to emissions of the compound in fact present a risk to

public health or welfare, or that it is appropriate to adopt controls to limit the emissions of

such a compound from motor vehicles or their fuels. The purpose of the list is to provide a

screening tool that identifies those compounds emitted from motor vehicles or their fuels for

which further evaluation of emissions controls is appropriate. While some of these

compounds may be regulated under separate EPA programs, this list is specific for those

compounds emitted from motor vehicles.

(D) Propionaldehyde should not be added to the list.

(1) Given the low expected toxicity of propionaldehyde, it should not be included

as a HAP from mobile sources.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 3

Response to issue 3.3.1(D)(1): We are not including propionaldehyde on the list of MSATs

at this time because we do not have an Agency consensus view as expressed on IRIS

regarding the potential serious adverse health effects associated with exposure to this

pollutant. EPA will continue to assess the possible inclusion of this compound on the list of

MSATs when we re-open this rulemaking in 2003.

(E) Styrene should be removed from the list.

(1) Styrene is not a fuel component and is only present as a product of

combustion. Because EPA does not establish any specific regulatory

requirements or criteria relating to styrene, because the toxicological review

of styrene is still underway, because its presence in gasoline is questionable,

and because of technical inconsistencies and data gaps relating to styrene

and mobile source emissions, EPA should defer the determination of whether

styrene is an MSAT to a future rulemaking. The current toxicological review
Response to Comments

December 20, 2000

Page 33

being conducted under the IRIS program will allow for an appropriate

technical determination in the future.

Letters:

Styrene Information and Research Center (IV-D-12) p. 2

Response to issue 3.3.1(E)(1): The Agency re-assessment of styrene is being conducted to

incorporate new information regarding potential noncancer and cancer health effects

resulting from exposure to this compound and will not result in the removal of styrene from

the IRIS database. In the NPRM we mistakenly listed styrene as a component of gasoline. 

Styrene is a product of gasoline combustion and is currently listed in IRIS for ingestion and

inhalation noncancer health effects. In keeping with our approach to list a compound as an

MSAT based on the presence of the compound in the emissions from motor vehicles or their

fuels and an Agency consensus view, as expressed on IRIS, that the compound has the

potential to cause serious adverse health effects, we are maintaining styrene on our list of

MSATs.

3.3.2: Additional Pollutants that EPA Should List

(A) EPA should investigate whether methanol and/or methyl nitrite should be

added to the MSAT list.

(1) Commenter attaches two articles discussing how the combustion of gasoline

with methanol and MTBE may create methyl nitrite, and that the production of

methyl nitrite in MTBE may be contributing to epidemics of asthma. The

commenter states the need to establish whether methanol and/or methyl

nitrite should be added to the list of mobile source air toxics. (Troops et al.,

"NO reduction over La2O3 using methanol, Catalysis Letters 2000, 64; P.M.

Joseph, "New Hypotheses for MTBE Combustion Products, 92nd Annual

Meeting Air & Waste Management Association, June 20-24, St. Louis,

Missouri.)

Letters:

Browne, William G. (IV-D-6) p. 1-2

Response to issue 3.3.2(A)(1): Regarding methyl nitrite, the Agency does not have an

Agency consensus as expressed on IRIS regarding the potential health effects of methyl

nitrite and therefore will not list methyl nitrite as an MSAT at this time. We did not include

methanol on our proposed list of MSAT because it was not identified in our analysis of

speciated emissions from motor vehicles. Instead, in the NPRM, we requested comment on

whether methanol and ethanol, by virtue of their use in alternative fuel vehicles, should be

included on the list. The commenter directed EPA to studies that identify methanol as an

emissions product of motor vehicles burning reformulated gasoline. In order to provide a full

opportunity for public comment regarding the information received, we will address the

addition of methanol to the MSAT list in a future rulemaking. We believe it is reasonable to

defer making a decision on listing methanol until after today’s rulemaking, because listing in

today’s rulemaking would not result in additional controls. The existing motor vehicle VOC
Response to Comments

December 20, 2000

Page 34

controls will reduce emissions of methanol along with other gaseous toxics and fuel controls

will need to be considered in subsequent rulemakings. As part of the future notice

addressing addition of methanol to our list of MSAT, we will also evaluate possible controls in

accordance with section 202(l)(2) as appropriate.

(B) EPA should include propionaldehyde and 2,2,4-trimethylpentane on the MSAT

list.

(1) The CAAA has specifically listed these pollutants as HAPs, and therefore

EPA need not draw any conclusions on the potential adverse health effects

associated with exposure to these pollutants.

Letters:

Consumer Policy Institute (IV-D-8) p. 4

(C) EPA should further study 2,2,4-trimethlypentane for potential inclusion.

(1) Acute and chronic testing of this compound should be continued to better

understand its potential toxicity.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 4

Response to issue 3.3.2 (B)(1) and (C)(1): We are not including propionaldehyde or

2,2,4-trimethylpentane on the list of MSATs at this time because we do not have an Agency

consensus view as expressed on IRIS regarding the potential serious adverse health effects

associated with exposure to this pollutant. EPA will continue to assess the possible inclusion

of these compounds in the list of MSATs when we re-open this rulemaking in 2003.

3.3.3: Additional Pollutants that EPA Should Not List

(A) EPA should not add methanol to the MSAT list.

(1) EPA did not make a full, reasonable and good faith effort to solicit broad

public input on the question of listing methanol as an MSAT. Without full

notice and comment on this issue, a decision on the part of EPA to list

methanol on the MSAT list could be viewed as arbitrary and capricious. 

Thus, if EPA chooses to press forward with listing methanol, it should do so

only in a supplemental or separate proposed rulemaking.

Letters:

American Methanol Institute (IV-G-03) p. 1-2, 4-5

Response to issue 3.3.3(A)(1): We did not include methanol on our proposed list of

MSAT because it was not identified in our analysis of speciated emissions from motor

vehicles. Instead, in the NPRM, we requested comment on whether methanol and ethanol,
Response to Comments

December 20, 2000

Page 35

by virtue of their use in alternative fuel vehicles, should be included on the list. During the

comment period, one commenter directed EPA to studies that identify methanol as an

emissions product of motor vehicles burning reformulated gasoline. In order to provide a full

opportunity for public comment regarding information received we will address the addition of

methanol to the MSAT list in a separate rulemaking.

(2) Even if EPA could overcome the procedural problems, EPA has produced no

data to support listing methanol as an MSAT. The data used for listing

methanol in IRIS are out-of-date and not comprehensive. The AWMA article

that EPA appears to rely on, although published in 1994, is based on

unrepresentative fuel in vehicles that are 16-24 years old. In addition, the

only comment mentioning methanol is more concerned with methyl nitrite; if

EPA wants to list an additional MSAT, it should consider that substance, not

methanol. Also, in listing methanol but not ethanol (which does yield toxic

exhaust products), EPA is treating ethanol and methanol inconsistently. 

Finally, EPA fails to analyze the overwhelming preponderance of biogenic

methanol versus mobile source emissions.

Letters:

American Methanol Institute (IV-G-03) p. 2-4

Response to issue 3.3.3(A)(2): As stated above, in order to provide a full opportunity for

public comment regarding the information received, we will address the addition of methanol

to the MSAT list in a separate rulemaking. In that action we will address any comments on

the data used at that time to support EPA’s decision.

(B) EPA should not add ethanol to the MSAT list.

(1) The Agency is correct in not listing fuel ethanol as an MSAT. 

Letters:

Renewable Fuels Association (Insert Comment Identification) p. 1-2

Response to issue 3.3.3(B)(1): The Agency agrees that ethanol should not be included in

the list of MSATs at this time because we don’t have peer-reviewed consensus Agency

opinion on the toxicity of ethanol as reflected in the Integrated Risk Information System. 

3.3.4: Listing of Diesel Exhaust 

(A) Commenter supports listing of whole diesel exhaust rather than just

particulate.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:
Response to Comments

December 20, 2000

Page 36

Commonwealth of MA DEP (IV-D-13) p. 1

NESCAUM (IV-D-10) p. 7

(2) Emissions control technologies could control diesel particulate while leading

to increased risks from exposure to gaseous diesel emissions.

Letters:

Consumer Policy Institute (IV-D-8) p. 4

(3) Diesel exhaust is a known or suspected cause of cancer or other serious

health consequences, and EPA should control it accordingly. One of the

commenters notes that according to a study by the State and Territorial Air

Pollution Program Administrators, more than 1100 people in the Portland

metro area will get cancer from diesel emissions over a lifetime of exposure. 

Another commenter supported the listing because it will help EPA address

diesel exhaust concerns, especially from non-road sources.

Letters:

Clean Air Network, et al (IV-D-38)

Oregon Environmental Council (IV-D-9) p. 1

Response to issues 3.3.4 (A)(1) through (A)(3): We agree that diesel exhaust should not

be listed as diesel particulate matter only because currently available science, while

suggesting an important role for the particulate phase component of diesel exhaust, does not

attribute the serious cancer and noncancer health effects independently to diesel particulate

matter separate from the gas phase components. We agree that, in part because of the

health effects attributed to diesel exhaust, appropriate controls on diesel exhaust should be

implemented. We are promulgating heavy-duty engine and vehicle standards and onhighway diesel fuel sulfur control requirements to achieve the greatest degree of control that

is technologically feasible. We do not agree that the data currently available provide

sufficient information from which to estimate the possible number of cancer cases attributable

to diesel exhaust in specific geographic regions. Instead of listing whole diesel exhaust, we

have chosen to be more specific about the toxic components of diesel exhaust by listing

diesel particulate matter and diesel exhaust organic gases.

(B) Commenter opposes classification of diesel exhaust as a mobile source toxic.

(1) One commenter stated that individual compounds and components of diesel

exhaust can be controlled with aftertreatment technology, but "diesel exhaust"

can only be controlled by restricting or eliminating the diesel engine. The

commenter argued that the Act was intended to focus not on the type of

engine but on the specific compounds emitted from vehicles which may pose

health concerns. Another commenter raised similar concerns and argued that

the listing would penalize unfairly the diesel engine because "diesel exhaust"

can not be reduced or eliminated even if the nature of the compounds within

the exhaust are modified. These and other commenters argued that EPA

must identify the specific components of diesel exhaust, study these
Response to Comments

December 20, 2000

Page 37

components, and establish controls for these components if necessary based

on those studies. For instance, one commenter noted, CO2 and water vapor

are the primary components of diesel exhaust, but clearly are not toxics. 

Another commenter argued that one of the criteria EPA used to list MSATs

was speciated emissions data, which clearly cannot apply to diesel exhaust.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 4-5

Alliance of Automobile Manufacturers (IV-F-1) p. 64

American Petroleum Institute (IV-D-21) p. 6

Engine Manufacturers Association (IV-D-39) p. 2-5, att.

Engine Manufacturers Association (IV-F-1) p. 10, 14, 16

Koch Petroleum Group (IV-D-36) p. 3

Marathon Ashland Petroleum, LLC (IV-D-15) p. 2, 6

National Petrochemical and Refiners Association (IV-D-33) p. 15

(2) A broad and vague listing of diesel exhaust fails to give diesel fuel producers

and diesel engine manufacturers a clear target to consider for potential

engineering changes. One commenter noted that even if manufacturers

eliminated all toxic compounds in the exhaust, diesel engines would still be

deemed to have toxic "diesel exhaust" emissions, which documents the illogic

of EPA's proposal. This vague listing also makes it impossible to establish a

metric for measuring the listed compound in the ambient air or in emissions,

or to determine the emissions reduction levels achievable through various

controls.

Letters:

Engine Manufacturers Association (IV-D-39) p. 3, 5, att.

Engine Manufacturers Association (IV-F-1) p. 14

Tosco (IV-D-41) p. 2

(3) Commenter cites its previous comments under the HDDE rule, and states that

the data supporting a connection between diesel exhaust and lung cancer are

extremely weak, with conflicting results, and limited evidence of causality in

the epidemiological database. These weak data are insufficient to support

inclusion of diesel exhaust as the only non-HAP on the MSAT list. Moreover,

as EPA acknowledges in the Technical Support Document for this

rulemaking, the non-cancer health effects identified for diesel exhaust appear

to be the same as those caused by fine PM. Thus there is no basis for

including diesel exhaust as an MSAT based on non-cancer health effects, but

not including other contributors to PM.

Letters:

International Truck and Engine Corp. (IV-D-30) p. 3
Response to Comments

December 20, 2000

Page 38

(4) Commenter argues that listing diesel exhaust is not scientifically supportable.

The composition of diesel exhaust is variable based on numerous factors. 

Moreover, over 99% of diesel exhaust consists of N, O2, CO2 and H2O, none

of which are toxic. In addition, diesel exhaust is not being treated equally with

other emission sources: by listing diesel exhaust as toxic, EPA is indicating

that emissions from one source are toxic while those same emissions from

any other source are not toxic. Finally, any listing should await the final

outcome of the formal review process by CASAC of the Diesel Health

Assessment Document prepared by EPA.

Letters:

Engine Manufacturers Association (IV-D-39) p. 2-6, att.

Engine Manufacturers Association (IV-F-1) p. 14-15

(5) While opposing the listing of diesel emissions as an MSAT, some

commenters did indicate that, at most, EPA should consider only diesel

particulate as a potential toxic contaminant, which is the only fraction of diesel

exhaust that EPA has identified as being of potential concern. EPA would

have to study diesel PM further to determine if it should be reported as a

separate toxic substance. One of these commenters noted that the Tier 2

and HDDE rules likely would address many of the concerns with diesel

exhaust, and that by focusing only on diesel PM, EPA would be able to

consider any remaining toxic issues with diesel exhaust. Another commenter

suggested listing particulate matter generally, and then studying the issue

further with a later decision as whether any particular subset of particulate

matter should be listed. Another commenter similarly noted that the IRIS

listing (which EPA uses as a basis for its proposal) used studies based on

diesel particulate matter, not whole diesel exhaust. This background is one

reason why EPA should not list diesel exhaust. However, this and other

commenters also believe that even diesel particulate matter should not be

listed. One reason is that the IRIS listing is currently under review because of

uncertainty. The commenters opposed to listing diesel PM stated that it is

unclear whether diesel PM is distinguishable from other sources of PM. The

appropriate listing, if any, would have to be PM generally, or PM within a

certain size range, because EPA cannot distinguish diesel PM from other

sources of PM. 

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 5

Alliance of Automobile Manufacturers (IV-F-1) p. 64-65

Detroit Diesel (IV-F-1) p. 75-76

Engine Manufacturers Association (IV-D-39) p. 5, att.

Engine Manufacturers Association (IV-F-1) p. 15

ExxonMobil (IV-D-16) p. 1-2

International Truck and Engine Corp. (IV-D-30) p. 4

Marathon Ashland Petroleum, LLC (IV-D-15) p. 6
Response to Comments

December 20, 2000

Page 39

Response to issues 3.3.3 (B)(1) through (B)(5): We have changed our designation of

diesel exhaust as an MSAT to diesel particulate matter and diesel exhaust organic gases

(DPM + DEOG). This listing approach is more precise about the components of diesel

exhaust expected to contribute to the observed cancer and noncancer health effects and

provides a framework for developing regulatory control strategies. Currently available

science, while suggesting an important role for the particulate phase component of diesel

exhaust, does not attribute the serious cancer and noncancer health effects independently to

diesel particulate matter separate from the gas phase components. Because the studies

cannot separate the health effects of the particulate and gaseous components of diesel

exhaust, nor identify specific compounds responsible for the health effects of diesel exhaust,

we are listing them together as a single MSAT.

We have made this change in listing diesel exhaust in response to the commenters

concerns. This listing excludes the nontoxic components of diesel exhaust (e.g., water

vapor, nitrogen, oxygen) while still including the components of diesel exhaust that are likely

to contribute to the cancer and noncancer hazard (with the exception of the gaseous phase

criteria pollutants, such as NOx, SO2 and CO which are subject to National Ambient Air

Quality Standards). The listing of DPM + DEOG provides Federal and State government,

industry, and public interest groups an ability to focus on the components of diesel exhaust

that pose a potential concern for public health as well as providing specific targets for

emissions reductions should future analysis indicate that additional controls become

necessary.

The Integrated Risk Information System (IRIS) listing for diesel engine emissions and

the summary of cancer and noncancer health effects described in the draft Health

Assessment Document for Diesel Exhaust are based on studies linking serious adverse

health effects to whole diesel exhaust exposure, using diesel particulate matter as the

measure of dose. Speciation of diesel exhaust is not a criteria for listing as an MSAT. To be

listed as an MSAT the candidate pollutant must be present in the emissions of motor vehicles

and have a listing on the EPA IRIS database.

We disagree with the comment that the data supporting a connection between diesel

exhaust and lung cancer are extremely weak. Individual epidemiological studies numbering

about 30 show increased lung cancer risks of 20 to 89 percent within the study populations

depending on the study. The draft Health Assessment for Diesel Exhaust evaluated only 22

of these studies because those were identified as being the most relevant for risk

assessment. Among these 22 studies, 16 reported statistically significant increased lung

cancer risks, ranging from 20 to 167 percent, associated with diesel exhaust exposure. Of

the remaining six studies, the authors report either negative or inconclusive results. 

Additional evidence supporting the identification of a cancer hazard for diesel exhaust

includes the observation of tumors in animals following applications of various fractions of the

diesel exhaust mixture to skin, and implantation of diesel particles in respiratory tissue. 

Recognizing that diesel exhaust is a complex mixture of carbon particles and associated

organics and other inorganics, it is unclear what fraction or combination of fractions is

responsible for the carcinogenicity and other respiratory effects. It has been shown,

however, that the carbon particles as well as the organics have the potential to be active

toxicological agents, either because of the potential to be irritants which cause inflamation, or

because of a capacity to produce mutagenic and/or carcinogenic activity. In the case of the
Response to Comments

December 20, 2000

Page 40

5

Health Effects Institute (1995) Diesel Exhaust: A Critical Analysis of Emissions,

Exposure, and Health Effects. Health Effects of Diesel Exhaust: Epidemiology; A.J. Cohen

and M.W.P. Higgins. p. 268.

6

Health Effects Institute (1995) Diesel Exhaust: A Critical Analysis of Emissions,

Exposure, and Health Effects. Health Effects of Diesel Exhaust: Epidemiology; A.J. Cohen

and M.W.P. Higgins. p. 268.

7

 National Institute for Occupational Safety and Health (NIOSH) (1988) Carcinogenic

effects of exposure to diesel exhaust. NIOSH Current Intelligence Bulletin 50. DHHS,

Publication No. 88-116. Centers for Disease Control, Atlanta, GA.

8

 International Agency for Research on Cancer (1989) Diesel and gasoline engine

exhausts and some nitroarenes, Vol. 46. Monographs on the evaluation of carcinogenic risks

to humans. World Heath Organization, International Agency for Research on Cancer, Lyon,

France.

organics (which exist both in particle and gaseous states in diesel exhaust) some have potent

mutagenic and carcinogenic properties. In addition, some evidence for the bioavailability of

these particle-adsorbed compounds supports a hypothesis that the adsorbed organics are

bioavailable to the lung as well as being transported to sites distant from the lung.

We conclude that the consistent finding of elevated lung cancer risk across several

different occupational workers (including truck drivers, railroad workers, heavy equipment

operators, and farm tractor drivers) support our determination that diesel exhaust is likely to

be carcinogenic to humans by inhalation exposure. The Clean Air Scientific Advisory

Committee (CASAC) of the Science Advisory Board concurred with the Agency that the

available data form a basis for the conclusion that diesel exhaust is likely to be carcinogenic

to humans by inhalation (public session October 12-13, 2000).

Our interpretation of the data is consistent with that of several experts, including an

expert panel (the Diesel Working Group) formed by the Health Effects Institute.5

 In the 1995

HEI study, Cohen and Higgins reviewed 34 epidemiological studies and concluded that “The

studies reviewed above suggest that exposure to diesel exhaust in a variety of occupational

circumstances is associated with small to moderate relative increases in lung cancer

occurrence and/or mortality. These elevations do not appear to be fully explicable by

confounding due to cigarette smoking or other sources of bias. Therefore, at present,

exposure to diesel exhaust provides the most reasonable explanation for these elevations.”6

 

EPA joins many other organizations in finding that diesel exhaust or diesel particulate

matter is a likely or probable human carcinogen. In the late 1980s, the International Agency

for Research on Cancer (IARC) determined that diesel exhaust is “probably carcinogenic to

humans” and the National Institute for Occupational Safety and Health classified diesel

exhaust a “potential occupational carcinogen.”7 8

 In 1996, the International Programme on

Chemical Safety of the World Health Organization listed diesel exhaust as a “probable”
Response to Comments

December 20, 2000

Page 41

9

 World Health Organization (1996) Diesel fuel and exhaust emissions: International

program on chemical safety. World Health Organization, Geneva, Switzerland.

10 Office of Environmental Health Hazard Assessment (1998) Health risk assessment

for diesel exhaust, April 1998. California Environmental Protection Agency, Sacramento, CA.

11U.S. Department of Health and Human Services (2000) Ninth report on

carcinogens. National Toxicology Program, Research Triangle Park, NC. 

ehis.niehs.nih.gov/roc/toc9.html.

human carcinogen.9 In 1998, the California Office of Environmental Health Hazard

Assessment (OEHHA, California EPA) identified diesel PM as a toxic air contaminant due to

the noncancer and cancer hazard and because of the potential magnitude of the cancer

risk.10 Most recently, the U.S. Department of Health and Human Services National

Toxicology Program designated diesel exhaust particles as “reasonably anticipated to be a

human carcinogen” in its Ninth Report on Carcinogens.11

We state in the NPRM that there is overlap between the noncancer health effects

observed with exposure to diesel exhaust and ambient PM, however, there is a wealth of

information available regarding noncancer health effects attributable to ambient PM relative

to the existing database for diesel exhaust. In addition, there are endpoints specific to diesel

exhaust such as the potential to stimulate allergen-induced allergic airway disease in

sensitive humans that have not been reported for ambient PM. Diesel engine emissions are

listed in the IRIS database for the observed noncancer health effects and therefore this

pollutant satisfies our listing approach for an MSAT. This listing is not based on health

effects attributable solely to diesel PM as the commenter asserts. Diesel PM was used as

the measure of dose in these studies which exposed laboratory animals to whole diesel

exhaust. The animal test data are quite definitive in providing a basis to anticipate a hazard

to the human lung resulting from diesel exhaust exposure based on the irritant and

inflammatory reactions observed in test animals. Thus, EPA believes, and CASAC

concurred, that it is appropriate to use the animal data to determine a reference

concentration for diesel exhaust (as measured by diesel PM). In the public session on

October 12-13, 2000, CASAC concurred with the calculation of the inhalation reference

concentration (RfC) presented in the July 2000 Health Assessment Document with the

addition of an uncertainty factor of three to extrapolate the observed health effects in animals

to humans. This additional uncertainty factor is being used on the recommendation of

CASAC and will result in an RfC of approximately 5 ug/m3

 which matches the current RfC

listed on IRIS. The CASAC of the Science Advisory Board has concurred with the findings in

the draft Health Assessment Document for Diesel Exhaust (public session October 12-13,

2000) and the Agency is in the processes of preparing a final Health Assessment Document

that will address the comments made by the CASAC panel. 

We are not listing ambient PM as an MSAT because it does not conform to the

approach described above for listing an MSAT. The Agency has specific information

regarding the cancer and noncancer hazard posed by diesel exhaust and we are acting on

this basis. It would be under inclusive to list only those compounds for which we have health

effects data because the myriad of compounds potentially responsible for the cancer and

noncancer health effects observed with exposure to diesel exhaust have not been identified.
Response to Comments

December 20, 2000

Page 42

12 “Update Heavy-Duty Engine Emission Conversion Factors for MOBILE6: Analysis

of Fuel Economy, Non-Engine Fuel Economy Improvements, and Fuel Densities,” U.S.

Environmental Protection Agency, EPA-420-P-98-014, May 1998.

(6) EPA has overstated the emissions benefits of the proposal by relying on

overly optimistic projections of the increase of diesel vehicle use. The Energy

Information Administration (EIA) projections of VMT growth rates are lower,

calling into question the reasonableness of EPA's estimates. EPA used EIA's

Annual Energy Outlook to forecast highway diesel consumption, yet the

difference in projected growth rates is significant. EPA has not adequately

justified the growth projections of new vehicle HDDEs. Similarly, EPA's

projected diesel production estimates are also out of line with EIA data. EPA

overstated highway diesel demand and baseline emissions, and as a result,

has overstated the emissions reductions benefits of the rulemaking.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 12-15

Response to issue 3.3.3.(B)(6): The emission inventories presented in this rule have been

revised from the proposal based on updated modeling information for on-highway vehicles. 

The modeling incorporates the impact of all our current and proposed on-highway control

programs, including the proposed 2007 heavy-duty engine standards. We base our onhighway inventory estimates on our assumptions of vehicle miles traveled (VMT) and

emission factor estimates. We base our on-highway diesel fuel consumption estimates on

our assumptions of vehicle miles traveled (VMT) and fuel economy.

With regard to VMT, the analysis uses updated heavy-duty vehicle VMT estimates. 

The revised VMT estimates were based on the Federal Highway Administration total VMT for

all motor vehicles apportioned to the various vehicle categories. New VMT splits broken out

by vehicle class and fuel type were developed in our efforts to create an updated version of

MOBILE5. As a result, the VMT projections increased by 40 percent for heavy-duty diesel

vehicles.

With regard to emission factors, we have updated the PM emission factors and HC

emission factors. The new PM emission factors were also developed in our efforts to create

an updated version of MOBILE5. The new HC emission factors incorporate revised

estimates of the levels to which manufacturers will certify under the proposed 2007 heavyduty engine standards.

With regard to fuel economy, historical fuel consumption estimates (1987-1996)

come from a report performed to support the upcoming MOBILE6 model.12 These historical

fuel consumption estimates suggest that fuel economy is improving. For future fuel

consumption estimates, we extrapolate the historical estimates into the future using a

constant, linear improvement in terms of miles per gallon.

As a check on our diesel fuel consumption estimates, we used EIA’s 1999 Annual

Energy Outlook (AEO 1999) to project highway diesel fuel production for use in the U.S. 
Response to Comments

December 20, 2000

Page 43

13 “Early Release of the Annual Energy Outlook 2001,” available at

www.eia.doe.gov/oaif/aeo/earlyrelease/index.html, Energy Information Administration,

downloaded from EIA web site on December 12, 2000.

According to AEO 1999, highway fuel consumption was projected to increase 1.5% per year. 

Commenters correctly point out that this is inconsistent with AEO 2000 which projects the

lower growth rate of 1.0% per year. This change in growth rate projections is based on

calculations using the gross domestic product index which are described in the EIA report. 

EIA is currently in the process of finishing AEO 2001 which is expected to show even higher

diesel fuel growth projections than AEO 1999. Based on preliminary information13, we

estimate that AEO 2001 will project an annual diesel consumption growth rate in the range of

1.6% to 1.9%. Based on these estimates, we believe that our fuel consumption projections

are supported by the projections made by EIA.

Both we and EIA project similar improvements in fuel economy into the future. This

means that both we and EIA project higher growth in VMT than in fuel consumption. As a

result, we estimate that the AEO 2001 VMT growth estimates will be as high or higher than

those we use in our emissions benefits calculations. Therefore, if anything, we may be

conservative in our estimates of the emission benefits of the proposed 2007 heavy-duty

engine standards.

(7) Supports EMA comments on this issue.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 5

Tosco (IV-D-41) p. 2

Response to issue 3.3.3.(B)(7): No response required

3.4: Suggestions to improve the Draft Technical Support Document

(A) Commenter offers suggestions to improve the Draft Technical Supporting

Document.

(1) EPA should discuss the need for chlorine to generate dioxin and document

the ability to separate diesel PM from other forms of PM.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 7-8

Response to issue 3.4(A)(1): Dioxin formed during the combustion process requires a

source of chlorine. Sources of chlorine in internal combustion engines include fuel, motor oil

and intake air. The ability of investigators to use chemical source profiles to separate diesel

PM from other sources of ambient PM has been demonstrated by 1) Fujita, E; Watson, JG;

Chow, JC; et al. (1998) Northern Front Range Air Quality Study, volume C: source

apportionment and simulation methods and evaluation. Prepared for Colorado State
Response to Comments

December 20, 2000

Page 44

University, Cooperative Institute for Research in the Atmosphere, by Desert Research

Institute, Reno, NV; 2) Schauer, JJ; Rogge, WF; Hildemann, LM; et al. (1996) Source

apportionment of airborne particulate matter using organic compounds as tracers. Atmos

Environ 30(22):3837-3855; and 3) Maricopa Association of Governments (1999) The 1999

Brown Cloud Project for the Maricopa Association of Governments Area, Final Report,

December 1999.

(2) EPA should: describe the oral slope factor; go into more detail in the

discussion of the toxicity of acetaldehyde and formaldehyde.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 7-8

Response to issue 3.4(A)(2): Using the EPA 1986 Risk Assessment Guidelines, a

carcinogen can be classified as a known, probable, or possible human carcinogen (Group A,

B or C, respectively). A quantitative assessment is performed depending on the

weight-of-evidence and the suitability of the available information regarding a relationship

between the dose of a compound and the effect it causes (dose-response data). If suitable

dose-response data are available, a quantitative assessment is calculated which can be

presented in one or more of three ways. If the agent is active upon ingestion, then the slope

of a dose-response curve generated from orally exposed animals or humans is calculated. 

This is referred to as the oral slope factor and is presented as risk per milligram of agent

ingested per kilogram of body weight per day. 

We disagree that there is a need to provide additional detail regarding the toxicity of

acetaldehyde and formaldehyde. The toxicity of each of the MSATs was discussed in

Chapter 3 in the Technical Support Document in enough detail to provide the essential

information regarding the cancer and noncancer health effects of each compound. Additional

information regarding the toxicity of each of these compounds can be found on EPA

Integrated Risk Information System web page: http://www.epa.gov/iris.

(3) EPA should: provide further support for diesel PM's contribution to emission

inventories presented in Section 3, Chapter 3 of the Technical Support

Document and clarify the discussion related to interpolating toxics emissions

over the full range of fuel TOG emissions.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 7-8

Response to issue 3.4(A)(3): EPA provides further support for the contribution of diesel PM

to emission inventories in Chapter 2 of the Health Assessment Document for Diesel Exhaust

that can be found at: http://www.epa.gov/ncea/dieslexh.htm. Regarding the interpolation of
Response to Comments

December 20, 2000

Page 45

toxics emissions over the full range of fuel TOG emissions, EPA has data on toxic versus

TOG emissions for normal emitters as a class versus high emitters as a class, obtained from

the Complex Model database. However, data are inadequate to establish a relationship

between toxics and TOG across the full range of TOG emissions. It is possible, as the

commenter suggests, that emissions of photochemically reactive toxics will not increase

linearly with TOG, but in the absence of adequate data, the Agency made a conservative

assumption that the relationship was linear.
Response to Comments

December 20, 2000

Page 46

ISSUE 4: CURRENT CONTROLS ON MSAT EMISSIONS

4.1: On-highway Controls 

(A) Current vehicle and fuel controls will achieve a significant reduction in air

toxics.

(1) Commenter notes that significant emissions will result from both Tier 2 and

the HD diesel fuel rules, achieving a 75-95% reduction in air toxics emissions

from mobile sources. Current controls are also estimated to reduce emissions

of benzene and total VOCs by 35% and diesel PM by 23%.

Letters:

Association of International Automobile Manufacturers (IV-D-7) p. 1

Engine Manufacturers Association (IV-D-39) p. 6, att.

Engine Manufacturers Association (IV-F-1) p. 11

(2) Efforts to reduce particulate and criteria pollutant emissions will also

concurrently reduce air toxics. For example, in-use testing of particulate

aftertreatment devices and BP Amoco ultra-low sulfur fuel in CA showed that

not only was PM reduced to non-detectable levels, but hydrocarbon

emissions were also reduced to near zero.

Letters:

Engine Manufacturers Association (IV-D-39) p. 7, att.

Engine Manufacturers Association (IV-F-1) p. 12

Response

See response to issue 5(A).

4.2: Off-highway Controls 

(A) Commenter notes that EPA has in place a comprehensive and stringent

program to control emissions from non-road sources, including increasingly

restrictive Tier 2 and Tier 3 emission standards.

(1) For non-road sources, Phase I regulations for spark-ignited engines less than

25 horsepower reduced VOC emissions by 30%, and Phase 2 regulations will

provide an additional 60-70% reductions over and above Phase I. Thus, the

continuing successes achieved in reducing MSAT emissions from on-highway

sources should be obtained from non-road sources as well, without the need

for any additional regulatory programs.

Letters:

Engine Manufacturers Association (IV-D-39) p. 7, att.
Response to Comments

December 20, 2000

Page 47

Response: We agree that the emission control programs we have put in place for sparkignited engines less than 25 horsepower will result in substantial MSAT reductions from that

category. However, we do not agree that the reductions we anticipate from those engines

make additional regulatory programs from nonroad sources unnecessary. As was stated in

the proposal, there are a lot of information gaps in our understanding of nonroad MSAT

emissions. These gaps need to be filled before we can make a determination on the need

for additional nonroad regulatory controls. Further, spark-ignited engines less than 25

horsepower represent only a part of all nonroad engines, and we believe that other

categories of nonroad engine types should be looked at to determine whether further

nonroad controls are appropriate.
Response to Comments

December 20, 2000

Page 48

ISSUE 5: VEHICLE-BASED CONTROLS 

(A) Commenter supports EPA's proposed conclusion not to impose further

controls on motor vehicle engines to control HAPs from mobile sources.

(1) Existing and proposed motor vehicle regulations developed to reduce

emissions of criteria pollutants will result in significant additional reductions of

MSAT emissions in the future, which further obviates the need for any

additional mobile source controls. Tier 2 and HDDE emissions standards will

result in substantial reductions in emissions of HAPs. EPA has predicted that

by 2020 these two regulations will reduce by 75% emissions of benzene,

acetaldehyde, formaldehyde, and 1,3-butadiene. VOCs are expected to

decrease by 76%, and diesel PM by 94% by 2020. (See related comments

under Issue 4.)

Letters:

Association of International Automobile Manufacturers (IV-D-7) p. 1

Engine Manufacturers Association (IV-D-39) p. 1, att.

International Truck and Engine Corp. (IV-D-30) p. 1-2

(B) EPA should evaluate several available options for MSAT vehicle standards.

(1) EPA should evaluate: fuel efficiency standards; an effective inspection and

monitoring program; use of OBD; and regulation of non-road vehicles. 

Another commenter stated similarly that, to control benzene and 1,3-

butadiene, EPA could introduce not only a more stringent fuel benzene cap,

but also could require OBD and the use of emission controls in non-road

engines. To control aldehydes, this commenter recommended that EPA: 

require existing trucks and buses be retrofitted with oxidation catalysts,

extend the useful life of HDDE, and introduce OBD for HDDE. For non-road

engines, EPA should apply the same standards listed above, as well as

impose the 15 ppm sulfur cap, and introduce more stringent PM and HC

engine standards.

Letters:

EarthJustice Legal Defense Fund (IV-D-32) p. 6

NESCAUM (IV-D-10) p. 3, 13-15

(C) Vigorous motor vehicle inspection and maintenance (I/M) programs are

essential to any motor vehicle emission control strategy, and should be

included as part of EPA's MSAT program.

(1) 10-30% of vehicles cause the majority of vehicle-related air pollution, as

emissions control equipment deteriorates in older vehicles and as general

wear and tear increase the rate of evaporative emissions. Enhanced I/M

programs are the single most cost-effective air pollution control program at a
Response to Comments

December 20, 2000

Page 49

cost of only $500 per ton of VOCs reduced. The commenter also noted that

EPA has recognized the importance of enhanced I/M programs to ensure that

the expected benefits of reducing tailpipe emission standards are realized.

Letters:

Environmental Systems Products (IV-D-25) p. 5, 16

Environmental Systems Products (IV-F-1) p. 53-57

Response to issues 5(A), (B), and (C): We proposed this rulemaking under Section 202(l)

of the Act which directs us adopt regulations to control MSAT emissions under Sections

202(a)(1) and 211(c)(1) of the Act. Section 202(a)(1), in turn, authorizes us to set emission

standards for new motor vehicles. In this context, we believe that our Tier 2 light-duty vehicle

program and our recently proposed heavy-duty engine and vehicle standards will achieve the

greatest degree of toxics control achievable under Section 202(l) at this time, and thus, fulfills

the statutory requirements. We agree with the commenters that other approaches such as

inspection and maintenance (I/M) may be able to reduce MSAT emissions from the in-use

fleet. However, we did not propose any such in-use programs in this rulemaking. 

Nevertheless, we will continue to consider the potential for in-use programs to achieve MSAT

reductions along with reductions in criteria pollutants.

While we are not establishing additional controls for MSAT emissions from new motor

vehicles in this rulemaking, it is worth discussing some of these promising in-use approaches

that may ultimately achieve further reductions in both MSAT and criteria pollutant emissions,

especially with respect to in-use maintenance and tampering. To address the

malmaintenance issue, EPA has established onboard diagnostic (OBD) requirements for

vehicle manufacturers. These OBD provisions require that vehicle manufacturers install

dashboard indicators that alert drivers to the need for emission-related maintenance, and

electronic monitors that store codes in the vehicle's computer to assist mechanics in the

diagnosis and repair of the malfunction. To address both the malmaintenance and tampering

issues, EPA is working with states to develop and optimize I/M programs that monitor the

emission performance of in-use vehicles. Recently we have been investigating how to best

integrate these programs to use the OBD systems to identify the high-emitting vehicles, as

well as the cause of the emission problem. For heavy-duty vehicles, I/M is more difficult

because it is not as easy to test the larger vehicles. However, we recently established new

OBD requirements for heavy-duty gasoline vehicles under 14,000 pounds GVWR, and

expect to propose similar requirements for all other heavy-duty vehicles within the next year. 

As these heavy-duty OBD programs take effect, it will be much more practical to develop

heavy-duty I/M programs that will achieve real emission reductions, especially for PM. With

respect to retrofitting existing vehicles with improved emission control devices, we believe

that it will be appropriate to address diesel retrofits after we have established the new

requirements for in-use diesel fuel. Some of the exhaust aftertreatment technologies being

considered in the recent heavy-duty diesel rule are especially appealing for use in retrofits

because they can be fitted to an existing vehicle as add-on devices without major engine

modifications. However, these technologies are not possible without the proposed changes

to the fuel.

We agree with the commenters that it is important that our useful life values be long

enough to adequately ensure that manufacturers design durable emission controls. That is
Response to Comments

December 20, 2000

Page 50

why we recently extended the minimum useful life for heavy heavy-duty engines from

290,000 miles to 435,000 (62 FR 54694 October 21, 1997). In that rulemaking we also

created new provisions that would require an even longer useful life in some cases. The

commenter did not provide data that would allow us to establish longer useful life values. 

Thus, while we may extend the minimum useful life values in the future we do not have a

sufficient basis to do so at this time. It is also important to note that the length of the useful

life is an important part of the standard setting process. If we were to change the minimum

requirements for useful life, we would need to reconsider the feasibility of the associated

emission standards. 

Nonroad engines are not mentioned in Section 202(l) of the Act. Therefore we did

not propose any new controls engines in this rulemaking. However, we will continue to

consider the potential for MSAT control along with control of other pollutants in our

rulemakings for nonroad engines under Section 213 of the Act. We have implemented

emission standards for most nonroad engines and are in the process of setting standards for

virtually all of the remaining uncontrolled classes of nonroad engines, as well as setting

newer more stringent standards for classes already controlled. These standards will reduce

MSAT emissions significantly from nonroad engines. 

(D) EPA should examine vehicle manufacturer's position on octane requirements

in case those might be reduced through improved engine technology or more

realistic engine fuel standards.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Gary Williams Energy Corporation (IV-D-3) p. 4

Response to issue 5(D): As described in the previous response, we do not have the

authority to specify the level of octane that a vehicle manufacturer can require solely to

control MSAT emissions. In addition, since higher octane allows higher combustion ratios,

lowering octane could increase fuel consumption. 

(E) Commenter writes to apprize EPA of innovative technology to control

emissions and increase fuel economy.

(1) Technology exists to prevent emission of partially oxidized fuel during the first

90 seconds of vehicle operation (which is responsible for almost 90% of

vehicle emissions). Commenter has enclosed two patents for this technology.

Letters:

Brooks, Timothy J. (IV-D-4) p. 2

Response to issue 5(E): See Response to issue 5(F) below.
Response to Comments

December 20, 2000

Page 51

(F) Commenter is developing an insulated catalytic converter designed to

significantly reduce hydrocarbon emissions, especially toxics, to reach low

emissions.

(1) Commenter notes, however, that EPA needs to develop the test procedures

to certify vehicles equipped with insulated converters. Commenter has

attached test results from real-world conditions to demonstrate the

effectiveness of such technology at reducing toxic emissions during cold-start. 

Commenter attached: MECA Demonstration Program of Advanced Emission

Control Systems for Light-Duty Vehicles, Final Report, May 1999; and Burch

and Biel, SULEV and "Off-Cycle" Emissions Benefits of a Vacuum-Insulated

Catalytic Converter, SAE 1999. In follow-up comments, the commenter

argued that adjustments to FTP-75 could be made to allow certification of this

technology without invalidating the test.

Letters:

Benteler Automotive (IV-D-24) p. all

Benteler Automotive (IV-G-4) p. all

Response to issues 5(E) and (F): We are aware of this innovative technology, and believe

that it has the potential to reduce MSAT emissions. However, as noted in the Technical

Support Document, we are uncertain whether it would be cost-effective. Thus we are not

basing new tighter emission standards on it. Nevertheless, we do recognize that our existing

test procedures are not appropriate to test vehicles equipped with these devices. We will

consider making the necessary modifications to the procedures in the future.

(G) EPA should use its section 202(l) authority to promote non-toxic and less toxic

mobile source alternatives that will change the reliance on the internal

combustion engine.

(1) This approach is warranted especially for this program given the long time

horizon for achieving the full benefits of the program (not until 2020). By that

time, many of these concerns can be addressed through increased use of fuel

cell and similar technology.

Letters:

Clean Air Network, et al (IV-D-38) p. 3

Response to issue 5(G): See response to 5(A,B&C).
Response to Comments

December 20, 2000

Page 52

ISSUE 6: FUEL STANDARDS 

6.1: General Comments to Support Anti-Backsliding Program

(A) Supports proposal to reduce benzene levels in fuels.

(1) Doing so will reduce levels of toxics emissions because benzene is a

combustion precursor of xylene, toluene and ethylbenzene.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 5

Response to 6.1(A)(1): We agree with this comment.

(2) Commenter provides no further supporting information or detailed analysis.

Letters:

Association of International Automobile Manufacturers (IV-D-7) p. 1

Response to 6.1(A)(1): No response required

6.2: General Comments Opposing Anti-Backsliding Program

[Note: Many refiner interests opposed the anti-backsliding program, and their general

positions are summarized in Issue 1.2. Their specific objections to elements of the antibacksliding program are detailed in the remaining subissues under Section 6.]

(A) The proposed rule will establish a regulatory program with multiple standards

throughout the country for an otherwise identical product, complicating facility

and company operations, regulatory enforcement, and the functioning of the

fuel markets.

(1) A single company will have different benzene content requirements for each

facility, which also will be different for current production and further

incremental production levels, and different from imported fuel levels. Not

only does this create complicated operations for refiners, but also, if the

market defaults to the tightest specification or the current average level, the

rule will, de facto, be requiring a cleaner product, on average, than currently

produced and will have deviated significantly from its "no backsliding"

purpose and assumed "no cost" premise.

Letters:

U.S. Department of Energy (IV-G-2) p. 2
Response to Comments

December 20, 2000

Page 53

Response to 6.2(A)(1): The commenter provided only a qualitative justification for its

allegation that our anti-backsliding program would unduly complicate operations and would

make coordination of operations within and between companies increasingly difficult. In fact

refineries already comply with fuel standards that are different for each facility under the antidumping program. Our anti-backsliding program would simply make these requirements

more stringent for CG, and would extend the refinery-specific nature of the requirements to

the RFG toxics requirement. The fact that we have changed to a toxic performance

requirement instead of the benzene content standard we proposed, and have included a

compliance margin, means that refiners not only have wide flexibility in how they meet their

refinery-specific toxic performance standard, but they can also take advantage of the low

sulfur standard of 30 ppm which begins phasing-in in 2004.

The market as a whole is unlikely to default to the tightest specification of all those applicable

to refineries across the U.S. Our anti-backsliding program will be enforced only at the

refinery gate, thus freeing downstream parties from the need to either comply with a current

national average toxics performance level or to guarantee that all product conforms to the

most stringent possible standard. As a result there is no reason to believe that our antibacksliding program will result in further reductions in toxics emissions than are strictly

required.

(B) The imposition of a new specification for gasoline will reduce blending

flexibility and limit refiners' ability to increase production or modify product

slates in response to market changes.

(1) The use of historical baselines, which will also require refiners to build in an 

additional compliance margin, minimizes increased production opportunities.

It also removes flexibility to blend, which reduces the ability to shift from CG

to RFG, substitute oxygenates, make changes to achieve early

desulfurization, or make similar changes.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 3-4

Response to 6.2(B)(1): Any new control on fuel places some limitations on a refiner's

flexibility. In the case of the anti-backsliding program we are finalizing in today's rulemaking,

however, we believe that the limitations are minimal and the corresponding costs negligible. 

The fact that we are finalizing a toxics performance requirement instead of the benzene

content standard we proposed, and are including a compliance margin, maximizes refiners'

ability to react to market changes while maintaining the overcompliance benefits exhibited in

1998 - 2000.

As described in Chapter 7 of our Technical Support Document, we do not believe that in

general production volumes over and above a refiner's baseline (1998 - 2000) volume will

result in significant increases in fuel benzene content. As a result it appears unlikely that our

anti-backsliding program will limit a refiner's ability to increase future production volumes for

either CG or RFG. In addition, the toxics performance requirement will allow refiners to take

the low sulfur gasoline requirements, including early sulfur credit generation, into account

when they comply with our anti-backsliding program, further maximizing their ability to
Response to Comments

December 20, 2000

Page 54

produce greater volumes of gasoline in the future, change the amount or type of oxygenate

used, or make other changes to their operations.

Finally, as described in our response to issue 6.8, establishing separate toxics performance

requirements for RFG and CG is an important element of our anti-backsliding program. 

Doing so ensures that the overcompliance benefits exhibited in RFG areas in 1998 - 2000

are not lost due to a shift in toxics performance between RFG and CG. Although this does

somewhat limit refiners' flexibility, we believe that the other elements of our anti-backsliding

program sufficiently maximize refiner's flexibility so that our program will not represent an

onerous burden.

6.3: State Pre-emption 

(A) States should not be allowed to impose any additional controls on air toxics.

(1) Differing State specifications would create "boutique" fuels and increase the

nation's vulnerability to supply disruptions and market volatility; reduce

flexibility; and contribute to logistical and pipeline problems. Some of these

commenters also noted that State and local specifications increase the need

for segregated batches, thus straining available refinery, pipeline, and

terminal tankage along with other blending and distribution resources.

Letters:

American Petroleum Institute (IV-D-21) p. 5

American Petroleum Institute (IV-F-1) p. 36

Chevron (IV-D-34) p. 2

Citgo Corporation (IV-D-5) p. 4

ExxonMobil (IV-D-16) p. 4

Koch Petroleum Group (IV-D-36) p. 2

Marathon Ashland Petroleum, LLC (IV-D-15) p. 2, 6

Phillips Petroleum Company (IV-D-20) p. 3-4

U.S. Department of Energy (IV-G-2) p. 3

Response to issue 6.3(A)(1): EPA recognizes the concerns expressed by the petroleum

industry that a patchwork of different state fuel standards, sometimes referred to as

“boutique” fuels, may increase the likelihood of disruptions in the fuel supply. In most

situations, EPA believes that a uniform national program is the best way to protect public

health and minimize disruption to the efficiency of the country’s fuel distribution network.

EPA’s general expectation is that States will limit the adoption of State fuel programs to

situations where local or unique circumstances warrant control.

Today’s rule does not change the existing scope of preemption under section

211(c)(4)(A). By adopting a toxics performance standard that mirrors the existing toxics

performance controls under the RFG and anti-dumping programs, we are not changing the

characteristics or components subject to control under 211(c)(1). As a result, today’s
Response to Comments

December 20, 2000

Page 55

rulemaking will not change the current ability, or the restrictions on the current ability, of

States to adopt fuel controls to address local toxics concerns.

 

(2) Commenters disagree that either of the two options in the preamble are

permissible under the Act to avoid State preemption. EPA's first option would

be to rescind the federal benzene standard if petitioned to do so by a State. 

This process is beyond the scope of section 211(c)(4). Under the CAA,

States can only avoid preemption if the fuel proposal is necessary to achieve

the NAAQS, and EPA cannot create other mechanisms to allow States to

regulate benzene. It is also inconsistent with the purpose of section 211(c)(4)

which is to avoid disruptions to the fuel distribution system. EPA's second

option is to regulate toxics instead of benzene which EPA believes could

enable States to specify benzene controls. However, State benzene controls

are already preempted by RFG and antidumping regulations. Section

211(c)(4) of the CAA prohibits States from imposing any control "respecting"

any fuel characteristic or component regulated by EPA. "Respecting"

generally means "related to," and certainly a State benzene control is related

to toxics control, particularly because benzene comprises 70% of toxics.

Letters:

American Petroleum Institute (IV-D-21) p. 3-5

American Petroleum Institute (IV-F-1) p. 36-37

ExxonMobil (IV-D-16) p. 2-4

Marathon Ashland Petroleum, LLC (IV-D-15) p. 6

National Petrochemical and Refiners Association (IV-D-33) p. 10-12

Response to issue 6.3(A)(2): Commenters argue that State controls on benzene are

controls “respecting” toxics performance and are therefore preempted under 211(c)(4)(A)

even in CG areas. Resolution of this issue would depend on how narrowly or broadly a court

decides to interpret the scope of preemption in 211(c)(4)(A). Because EPA is not changing

the scope of preemption as it existed before promulgation of this rule, EPA does not believe it

is necessary to resolve commenters’ argument at this time. 

(3) EPA has clearly stated in prior rules such as the RFG and anti-dumping rules,

that federal rules should preempt State action to avoid an inefficient

patchwork of potentially conflicting regulations. EPA should recommit to strict

adherence with the CAA's preemption rule.

Letters:

American Petroleum Institute (IV-D-21) p. 5

Chevron (IV-D-34) p. 2

National Petrochemical and Refiners Association (IV-D-33) p. 10-12

Sunoco, Inc. (IV-D-23) p. 2

Response to issue 6.3(A)(3): We continue to believe that the characteristics and

components subject to controls under our RFG regulations preempt non-identical State

controls respecting those characteristics or components in RFG areas. Likewise, our anti-
Response to Comments

December 20, 2000

Page 56

dumping controls preempt State controls in CG areas respecting those characteristics or

components. Today’s rulemaking does not alter the preemptive effect of our RFG and antidumping rules, but instead mirrors these controls. 

(B) States should be allowed to regulate MSATs to protect their citizens from

significant health risks.

(1) EPA has failed to fulfill its mandate to protect the public from risks posed by

MSATs, and at the same time preempts States from taking action to protect

their citizens. In the absence of an effective national MSAT program, EPA

should set a framework that avoids State preemption and allows States to

address these risks.

Letters:

Commonwealth of MA DEP (IV-D-13) p. 1

Consumer Policy Institute (IV-D-8) p. 3-4

NESCAUM (IV-D-10) p. cvr. ltr.

STAPPA, ALAPCO (IV-D-22) p. 3-4

STAPPA, ALAPCO (IV-F-1) p. 46-48

Response to issue 6.3(B)(1): Today’s rule adopts toxics performance standards that apply

to the same characteristics and components as the existing RFG total toxics performance

standard and CG exhaust toxics performance standard. As a result, today’s standards do not

change the scope of preemption that existed prior to promulgation of this rule. As discussed

in the preamble to both the final and proposed rules, we believe a toxics performance

standard may not cause States to be prohibited under section 211(c)(4)(A) from setting their

own fuel benzene standard. At the same time, as discussed in the response to 6.3(A)(2),

there is an argument that State controls on benzene are preempted as controls “respecting”

toxics performance even in CG areas where there is no benzene standard. Because EPA is

not changing the scope of preemption as it existed before promulgation of this rule, EPA

does not believe it is necessary to resolve commenters’ argument at this time.

(2) States should have the option to develop programs tailored to address

problems specific to that State.

Letters:

Bluewater Network (IV-D-29) p. 2

Commonwealth of MA DEP (IV-D-13) p. 2

Puget Sound Clean Air Agency (IV-D-27) p. 1

STAPPA, ALAPCO (IV-D-22) p. 3-4

Response to issue 6.3(B)(2): Today’s proposal does not change the scope of preemption

and preserves whatever authority States currently have to address local problems. 

6.4: California Exemption 
Response to Comments

December 20, 2000

Page 57

(A) Commenter concurs that California gasoline should be excluded from these

requirements.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

ExxonMobil (IV-D-16) p. 6

Response to 6.4(A)(1): See response below 6.4(B)(1)

(2) California's program for controlling gasoline benzene emissions is already

more stringent than the federal RFG program and will become more stringent

when CARB Phase 3 gasoline is introduced.

Letters:

American Petroleum Institute (IV-D-21) p. 9

British Petroleum (IV-D-19) p. 2-3

California Air Resources Board (IV-D-1) p. 1-2

Chevron (IV-D-34) p. 1

Kern Oil & Refining, Inc. (IV-D-31) p. 5

National Petrochemical and Refiners Association (IV-D-33) p. 9

Tosco (IV-D-41) p. 4

Western Independent Refiners Association (IV-D-40) p. 3

Response to 6.4(A)(2): See response below 6.4(B)(1)

(3) California's gasoline should be exempted so long as the California standard is

more stringent.

Letters:

Bluewater Network (IV-D-29) p. 2

Response to 6.4(A)(3): See response below 6.4(B)(1)

(4) Commenter also agrees that the production of non-California RFG or CG by a

California refinery should not be excluded from this rule. (But see Issue 6.11.6

for flexibility related to this non-CA production.)

Letters:

Tosco (IV-D-41) p. 4

Response to 6.4(A)(4): See response below 6.4(B)(1)

(B) Commenter finds EPA's rationale for the California exemption to be lacking

continuity with other portions of the proposal.
Response to Comments

December 20, 2000

Page 58

(1) EPA has shown that future California standards may be less stringent than

those proposed by EPA for RFG. Under the current proposal, some nonCalifornia refiners will be held to benzene content levels far lower than those

of California refiners.

Letters:

Phillips Petroleum Company (IV-D-20) p. 5

Response to 6.4(A)(1), 6.4(A)(2), 6.4(A)(3), 6.4(A)(4), 6.4(B)(1): In the NPRM, we

proposed to exempt California gasoline from the proposed fuel benzene standard because it

would be highly unlikely that California gasoline benzene levels would backslide, or increase,

relative to the benzene levels of the proposed baseline period. We indicated that current

California benzene levels and the upcoming more stringent California benzene requirements

(Phase 3) would preclude benzene increases. As can be seen from the comments above,

most commenters on this issue agreed with this approach, and most of those commenters

agreed because of the increased stringency of the upcoming California Phase 3 gasoline

rules. We believe the support of these commenters would extend to the final form of the rule,

a toxics performance requirement.

The commenter at 6.4(B) questions EPA’s rationale for exempting California gasoline

because some non-California refineries (producing presumably non-California gasoline)

would be held to a more strict standard (under the proposal, benzene levels lower than the

average required of California refiners under California’s rules). Under the proposed rule, it

is possible that a producer of gasoline would have baseline period benzene levels of less

than 0.7 percent by volume (the Phase 2 California average gasoline standard). However,

both the proposed rule and today’s final rule were anti-backsliding requirements; that is, the

standard was relative to what each individual refinery produced during the baseline period. 

We are not providing an exemption to producers of California gasoline because of the

magnitude of their average fuel benzene (in the case of the proposal) or their average toxics

emissions performance (for our final rule). Rather, we are exempting California gasoline

because we believe that the combination of the current California gasoline regulations and

the upcoming more stringent California gasoline regulations effectively limit backsliding of

California gasoline by producers of California gasoline.

6.5: Form of Standard

6.5.1: Benzene Content Standard 

(A) Commenter supports a standard for gasoline benzene content over one based

on total toxics emissions.

(1) Because benzene accounts for about 67% of the total toxic mass emissions

from mobile sources, benzene is a reasonable surrogate for other toxics. If a

toxics standard were promulgated, refiners would likely focus on current

benzene controls to reduce total toxics. Some commenters noted that a

benzene content standard provided greater flexibility and would be simpler to

administer than a toxics performance standard. One commenter also argued
Response to Comments

December 20, 2000

Page 59

that the simplicity of the benzene content standard made the 2002 start date

manageable, which may not be the case for a toxics performance standard.

Letters:

American Petroleum Institute (IV-D-21) p. 10

British Petroleum (IV-D-18) p. 1

Marathon Ashland Petroleum, LLC (IV-D-14) p. 7

Phillips Petroleum Company (IV-D-20) p. 4

Response to 6.5.1(A)(1): We agree that benzene emissions account for a majority of total

toxics emissions from gasoline-powered light-duty cars and trucks for those toxic compounds

included in the Complex Model. This fact is one reason that we proposed controls on

gasoline benzene content. See also Table IV.A-1 in the Technical Support Document. 

However, as stated in the NPRM, an anti-backsliding program that focuses on gasoline

benzene content ignores emissions of other toxic compounds which could theoretically

increase. In addition, as described more fully in our responses to Issue 6.13, a gasoline

benzene content standard could actually result in non-negligible costs.

A gasoline benzene content standard does not offer refiners an advantage over a toxic

emissions performance requirement. As the commenter correctly points out, refiners may

very well focus on control of fuel benzene content even under a toxic performance

requirement. However, under a toxic performance requirement refiners would also have the

flexibility to make other changes to their fuel in order to meet the standard, providing

opportunities for doing that which benefits each individual refinery the most.

We do not believe that a benzene content standard would be simpler to administer than a

toxics performance requirement. Since CG currently has no controls for fuel benzene

content, a benzene content standard for CG would actually represent a new compliance

requirement for refiners, complicating the set of fuel standards that they must already comply

with for gasoline. A toxics performance requirement, on the other hand, would simply replace

the existing requirements for CG and RFG with a new numerical standard. See also our

response to issue 6.5.3(A)(1). We also believe that the 2002 start date for our antibacksliding program is no less manageable with a toxics performance requirements than with

a benzene content standard, since refiners will have substantial control over toxics emissions

through fuel benzene controls and can choose to focus on the latter if doing so is most

beneficial for them. See also our responses under Issue 6.7.

(2) Control on benzene versus toxics, without new downstream standards, would

also be more appropriate within the current regulatory environment. As EPA

notes, benzene is the primary element of the toxics control strategy in

meeting RFG and anti-dumping requirements.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 4-5
Response to Comments

December 20, 2000

Page 60

Response to 6.5.1(A)(2): Designing our anti-backsliding program to be consistent in form

with the currently regulatory requirements does offer some advantages in terms of testing

and reporting requirements as well as compliance familiarity. However, the toxic

performance requirement we are finalizing today is actually a more direct extension of current

regulatory requirements than the benzene content standard we proposed in the NPRM. 

Although fuel benzene content is controlled directly under the RFG program, it is not directly

controlled under the anti-dumping program applicable to conventional gasoline (CG). In

contrast, we have designed our anti-backsliding toxic performance requirement to be

consistent with the total toxics standard for RFG, measured in percent from the statutory

baseline, and the exhaust toxics standard for CG, measured in mg/mi.

6.5.2: Toxics performance requirement 

(A) Supports a toxics performance standard instead of a gasoline benzene content

standard.

(1) An exhaust toxics standard would allow a refiner more flexibility in meeting

the compliance targets while meeting EPA's objectives. Because a reduction

in gasoline sulfur results in a decrease in toxics, a toxics standard would

eliminate the problems associated with an increase in benzene content

resulting from the Tier 2 and diesel fuel sulfur standards.

Letters:

Placid Refining Company, LLC (IV-D-1) p. 3

Response to 6.5.2(A)(1): We agree with this comment. According to the refinery modeling

discussed in Chapter 7 of our Technical Support Document, fuel benzene content would in

fact increase concurrent with the low sulfur standard of 30 ppm which will begin phasing-in in

2004. Since a toxics performance requirement allows increases in toxics emissions due to

increasing fuel benzene content to be offset with decreases in toxic emissions due to lower

sulfur, refiners will in fact reap the benefits of low sulfur when complying with the toxics

performance requirement we are finalizing today.

(B) Supports continued exploration of a toxics compliance formula.

(1) In theory, this approach limits overall pollution while maintaining refiner

flexibility, but this theory has not been analyzed thoroughly. To date, it

appears EPA's moves on sulfur and benzene actually undermine the refiner's

ability to adjust various components in order to manufacture a gasoline that

meets EPA's requirements.

Letters:

Gary Williams Energy Corporation (IV-D-2) p. 4
Response to Comments

December 20, 2000

Page 61

Response to 6.5.2(B)(1): We agree that a toxics performance requirement places more

direct controls on toxics emissions than a fuel benzene content standard while

simultaneously providing refiners with the flexibility to comply with our anti-backsliding

requirement in the way that most benefits their economic situation. This is one reason why

we have decided to finalize a toxic performance requirement instead of the benzene content

standard we proposed. In so doing, the toxics requirements already in place in the RFG and

anti-dumping programs will effectively become more stringent (on average across the U.S.)

and there will be no new controls on fuel benzene content in this rulemaking that might limit a

refiner's flexibility to meet the toxics requirements for RFG and CG.

We believe that the refinery modeling described in Chapter 7 of the Technical Support

Document sufficiently analyzed the impacts of a toxics performance requirement on average

refiner flexibility. That modeling allowed us to conclude that a toxics performance

requirement would be more appropriate for our anti-backsliding program than the proposed

benzene content standard, due in part to the potentially non-negligible costs associated with

a benzene content standard. The modeling also indicated that toxics emissions would likely

decrease after the low sulfur gasoline standard of 30 ppm goes into effect, suggesting that

the 30 ppm sulfur standard will not impose an additional burden on refiners in terms of

compliance with the RFG and anti-dumping toxics requirements. Note that the low sulfur

standard of 30 ppm was implemented only to enable the next generation of light-duty

aftertreatment to operate effectively.

(C) IF EPA promulgates a TES in the future, then EPA must at that time retire the

BCS.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Phillips Petroleum Company (IV-D-20) p. 4-5

Response to 6.5.2(C)(1): The comment implies that the combination of a toxics

performance requirement and a benzene content standard at any point in the future would be

redundant and would represent an unfounded burden upon refiners. Since we are not

finalizing the benzene content standard, there will be no need to retire it in the future should

we determine, as part of our Technical Analysis Plan, that additional controls on toxics are

warranted sometime after 2003. 

(D) Supports a regional approach to toxics, rather than refinery-by-refinery for

RFG.

(1) If EPA decides to use a baseline toxics performance standard approach, EPA

should establish a regional toxics performance standard. The regional

standard would be translated appropriately back to the refinery gate for

refineries supplying that region. This approach, in conjunction with a regional

refiner trading program, would minimize the overall cost of the program,

facilitate its earlier implementation, and have less adverse impact on gasoline
Response to Comments

December 20, 2000

Page 62

supply. Another commenter recommended that this approach also should be

coupled with no further controls on CG and the elimination of the oxygenation

mandate.

Letters:

American Petroleum Institute (IV-D-21) p. 7

ExxonMobil (IV-D-15) p. 8

(2) Commenter provided no further supporting information or detailed analysis.

Letters:

Marathon Ashland Petroleum, LLC (IV-D-14) p. 5

Response to 6.5.2(D)(1) and (D)(2): There are several ways in which we could have set and

applied the baseline for our anti-backsliding program, all of which would in theory maintain

the same toxics performance levels for the U.S. as a whole. These include a single

nationwide baseline applicable to all refineries, regional baselines applicable to all refineries

within each region, and refinery-by-refinery baseline. In the absence of credit trading,

however, a nationwide or regional approach would mean that some refineries would be over

the applicable toxics baseline and some would be under. Those that were over the baseline

would be forced to change their operations or install new equipment in order to comply with

the nationwide or regional baseline. As a result the national average toxics emissions would

fall below the level strictly required by an anti-backsliding program, with some refiners

incurring non-negligible costs in the process. We do not consider these costs and the

associated emission reductions to be warranted in the short term.

Inclusion of credit trading under a nationwide or regional program might minimize or even

eliminate the additional toxics emission reductions that would otherwise result. However, the

costs to many refiners could continue to be significant even though toxics emissions are no

better than they were in 1998 - 2000 for the nation as a whole. Under credit trading, refiners

that overcomply with the applicable toxics performance requirement would sell credits to

those refiners who undercomply. According to economic theory, refiners that undercomply

would be willing to pay an amount for those credits which is equal to, but no greater than, the

cost of meeting the toxics performance requirement on their own. The result is that the

economic burden on many refiners who undercomply with a nationwide or regional standard

could be the same whether or not credit trading is allowed. For further discussion of credit

trading, see our responses under Issue 6.11.3.

As part of its justification for a regional program, one refiner commented that the significant

overcompliance in toxics emissions exhibited in 1998 - 2000 is predominately due to those

refineries that overcomplied on fuel benzene content. We agree that the majority of toxics

overcompliance is due to fuel benzene content overcompliance. However, it would appear

that a regional program, with or without credit trading, would actually increase costs because

the economic incentive to reduce fuel benzene content would continue to be refinery-specific. 

Refineries for which benzene reduction was not profitable in 1998 - 2000 would likely

undercomply with a regional standard in the future, and so would need to either buy credits or

install new equipment. Thus it appears that a refinery-by-refinery set of toxic performance
Response to Comments

December 20, 2000

Page 63

baselines is the most appropriate means for minimizing costs while simultaneously

preserving the overcompliance toxics benefits exhibited in 1998 - 2000.

6.5.3: Benzene Emissions Standard 

(A) Opposes benzene emissions standard.

(1) A BES offers no simplicity over a toxics emissions performance standard and

is not a meaningful alternative at this time.

Letters:

ExxonMobil (IV-D-15) p. 8

Phillips Petroleum Company (IV-D-20) p. 5

Response to 6.5.3(A)(1): Both the benzene emissions standard on which we took comment

and the toxic performance requirement we are finalizing today are functions of several fuel

properties, most notably fuel benzene content. As a result, the limitations that they impose

on the formulation of gasoline are largely overlapping. Therefore, from the perspective of a

refiner complying with our anti-backsliding program, a benzene emissions standard would be

no simpler to administer or manage than a toxics performance requirement. 

(B) Supports a benzene emissions standard over a benzene content standard.

(1) Benzene in fuel is an imperfect determinant of vehicle benzene emissions

because the benzene present in vehicle fuels is largely combusted. Fuel

sulfur levels and Reid Vapor Pressure can also affect vehicle benzene

emissions. A successful program to limit ambient benzene concentrations

will have to address total vehicle benzene emissions.

Letters:

U.S. Department of Energy (IV-G-2) p. 1-2

Response to 6.5.3(B)(1): By far the fuel property that has the largest impact on benzene

emissions is fuel benzene content. According to the Complex Model, our current best

indicator of the effects of fuel properties on toxics emissions, the effect of fuel benzene

content on benzene emissions is several times greater than the fuel property with the next

highest impact, aromatics. For this reason it was appropriate for us to consider fuel benzene

content in the NPRM as a means for controlling benzene emissions. However, the

commenter is correct in that other fuel properties can have significant effects on toxics

emissions, and that the most direct and certain means of limiting ambient concentrations of

toxic pollutants is to place direct controls on tailpipe emissions. This is one reason that we

have decided to finalize a toxics performance requirement instead of a benzene content

standard. 

As described in the Technical Support Document, we do not believe that a focus only on

benzene emissions provides the greatest degree of protection against backsliding with
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December 20, 2000

Page 64

respect to 1998 - 2000 toxic emission levels. It is true that by setting controls on benzene

emissions one has the greatest possible degree of control over ambient benzene

concentrations. However in this case emissions of other toxic compounds could theoretially

increase without any limitations other than the current RFG and anti-dumping standards with

which refiners are significantly overcomplying. We have therefore concluded that a toxics

performance requirement is a better means for maintaining the overcompliance exhibited in

1998 - 2000 than a simple benzene emissions standard.

6.5.4: National Average-Based vs. Refinery-Based Standards 

(A) Commenter expressed support for a nationwide standard for CG and RFG.

(1) A nationwide standard would prevent the cleaner refinery from being

penalized for early reductions and would encourage future voluntary

reductions. The limit could be set at 1998-99 industry average levels. One

commenter added that overall benzene levels would not suffer because

refiners over the average would have to reduce their levels.

Letters:

Amerada Hess Corporation (IV-D-14) p. 3, 7-8

Citgo Corporation (IV-D-5) p. 1, 3

Response to issue 6.5.4(A)(1): While EPA may consider such a program in the future, the

current rule is designed to avoid increases in total toxic emissions from gasoline while

imposing the least cost on the refining industry. The approach ensures that the control is

achievable in the near term. EPA’s modeling predicts that even after RFG II and Tier 2 low

sulfur gasoline, the typical refinery in PADDs I and III will not incur more than negligible costs. 

The regulations also contain provisions for baseline adjustments and temporary relief in the

event of unforeseen circumstances. 

EPA does not believe the refinery-specific anti-backsliding approach unfairly

penalizes early reductions. Some refineries have found it economically advantageous to

overcomply with the toxics performance standard for RFG and, to a lesser extent, CG. In

many cases, the financial incentive of overcomply is due to proximity to a market for chemical

benzene. Since each refinery is unique in terms of construction and location, any single

standard will create varying degrees of challenges. In this case, those refineries that have

taken advantage of a local benzene market will find themselves without the significant

cushion of overcompliance that they had previously enjoyed. If EPA establishes a nationwide standard, those refineries not located near a petrochemical market will be “penalized” in

a different way.

(2) A nationwide baseline set at a level just higher than the 1998-99 industry

average baseline would enable refiners to remain in compliance despite

uncertainties in equipment operation, crude supply, market requirements,

weather, and other variables.

Letters:
Response to Comments

December 20, 2000

Page 65

Koch Petroleum Group (IV-D-36) p. 1

Response to issue 6.5.4(A)(2): The Agency has established a compliance margin for the

final rule for RFG and CG and expanded the baseline period from two year to three years. 

These changes should allow refineries to remain in compliance despite the typically

fluctuations in equipment operation, crude supply, market requirements, weather, and other

variables.

(3) Commenter noted this preference especially for CG.

Letters:

Phillips Petroleum Company (IV-D-20) p. 2-3

Response to issue 6.5.4(A)(3): See response to issue 6.5.4 (A)(2). 

(B) Supports a refinery-based program.

(1) Refinery-based anti-backsliding averages are important for consistency,

simplicity, flexibility, and quicker implementation. More complicated programs

would necessitate implementation delays. The commenter notes that the

current RFG toxic and conventional anti-dumping exhaust toxic averaging

control programs are refinery-based and do not impose control requirements

on downstream entities.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 4-5

Response to issue 6.5.4(B)(1): The Agency agrees with the comment.

6.5.5: Alternative Standards 

(A) EPA should establish a minimum benzene level or floor.

(1) Those refiners which extract almost all the benzene from their reformate have

little flexibility to control benzene to very low baseline levels. Any unexpected

spike in benzene levels would make it difficult to compensate with future

operations because the refinery's normal operation is maximizing benzene

extraction. Establishing a floor would allow EPA to maintain the basic

structure of the proposal while not adversely affecting the cleanest refiners.

This approach also could provide incentives to produce additional RFG

volumes. Also, the use of a floor should not affect future benzene levels

because refiners that invested in extraction facilities will not intentionally

increase benzene levels.

Letters:

Citgo Corporation (IV-D-5) p. 1-4
Response to Comments

December 20, 2000

Page 66

National Petrochemical and Refiners Association (IV-D-33) p. 6

Response to issue 6.5.5(A)(1): EPA has made significant changes from proposal to final in

order to create greater flexibility for refineries. Changes which have enhanced flexibility

include: increasing the baseline period from two to three years; shifting to a toxics

performance requirement; adding a compliance margin; and allowing for credit and deficit

carryforward. Given these substantial flexibilities provided in the final rule, the Agency does

not agree with the commenter that establishing a minimum floor for those refineries that have

established the lowest baselines is necessary.

(2) Commenters recommended that a reasonable floor would be a minimum of

0.7 vol.% for CG and either 0.5 or 0.65 vol.% for RFG.

Letters:

Citgo Corporation (IV-D-5) p. 1-4

National Petrochemical and Refiners Association (IV-D-33) p. 6

Response to issue 6.5.5(A)(2): See response to issue 6.5.5(A)(1).

(B) Refiners that produced benzene for the chemicals market during the baseline

period should be allowed to increase their baselines to an established

minimum.

(1) Doing so would avoid the economic hardship which would accompany a

reduction in the benzene chemicals market.

Letters:

Tosco (IV-D-41) p. 3

Response to issue 6.5.5(B)(1): See response to comment 6.5.5(A)(1).

(C) EPA should establish a standard that will provide maximum public health and

environmental protection and full flexibility for state and local agencies that

wish to go beyond the federal program.

(1) Whether this is accomplished through a toxics performance standard, another

of the identified options, or an approach that was not presented in the EPA

proposal, EPA should make health and environmental protection and

state/local flexibility very high priorities in developing the rule.

Letters:

STAPPA, ALAPCO (IV-D-22) p. 4

Response to issue 6.5.5(C)(1): The final rule was designed to capture the greatest amount

of overcompliance while imposing less costs on industry than the proposed benzene content

standard. The final form of the standard does not alter the legal status quo in terms of a
Response to Comments

December 20, 2000

Page 67

state’s ability to establish more stringent controls on components of conventional gasoline

that produce toxic emissions.

6.6: Ability to Meet Baseline Levels at No Cost

(A) One reason the proposal is too stringent and will impose costs on refiners is

because refiners will need to maintain a compliance cushion so that

unanticipated exceedances do not jeopardize compliance.

(1) Reducing the compliance cap would force refiners to further reduce the

benzene content to maintain a "compliance comfort zone." One commenter

suggests that, at a minimum, EPA should consider a 20-25% compliance

cushion for those refiners with very low baselines. Another commenter

suggests a 10% compliance margin. Another commenter stated that, based

on its operating experience, annual benzene levels can vary by 10-25%. So,

EPA should consider a compliance margin in that range, with a maximum

limit for RFG. The commenter argued that this approach would provide

necessary flexibility to refiners while minimizing any air quality impact.

Letters:

American Petroleum Institute (IV-D-21) p. 2

American Petroleum Institute (IV-F-1) p. 35

Citgo Corporation (IV-D-5) p. 3

ExxonMobil (IV-D-16) p. 2, 5

Gary Williams Energy Corporation (IV-D-3) p. 1-2

Koch Petroleum Group (IV-D-36) p. 1

Marathon Ashland Petroleum, LLC (IV-D-15) p. 4-5

Murphy Oil Corporation (IV-D-17) p. 4

Phillips Petroleum Company (IV-D-20) p. 3, A-2, A-3

Sunoco, Inc. (IV-D-23) p. 2

Response to 6.6(A)(1): We agree that, in the process of complying with a given standard,

refiners will generally aim for some level below that standard to ensure compliance. In the

context of this final rulemaking, we recognize that requiring refineries to be no higher than

their average 1998 - 2000 production may actually cause refineries to reduce the toxic

performance of their gasoline below the applicable standard resulting in costs to the industry

that are not reasonable in the short term. It is for this reason that we have decided to include

a compliance margin in the toxics performance requirement we establish for every refinery.

To determine the average compliance margin necessary to ensure that refineries will not

need to overcomply with the new anti-backsliding requirement, we analyzed batch data from

a random selection of refineries. The analysis allowed us calculate the magnitude of the

compliance margin to apply to each refinery's anti-backsliding baseline that would forestall a

refinery's need to reduce toxic emissions further than required under our anti-backsliding

program. A detailed discussion of the calculation of compliance margins is given in Chapter

7 of the Technical Support Document.
Response to Comments

December 20, 2000

Page 68

Our analysis of toxic performances indicates that year-to-year variations in the national

average are very small. As a result, we have not incorporated the effects of year-to-year

variations in the determination of the compliance margin. However, despite the fact that the

national average toxic performance appears quite stable from year to year, variations can be

more substantial for individual refineries. This is one reason that we have expanded our

baseline period from two to three years. The three year baseline period of 1998 - 2000

should reduce the impacts of any year-to-year variations for individual refineries.

(2) Small refiners will have to adopt measures to over-comply in order to ensure

compliance consistently and risk free with the new standards for 2002. 

Otherwise, they may not be able to avoid the significant penalties associated

with a violation.

Letters:

U.S. Small Business Administration (IV-D-26) p. 2

Response to 6.6(A)(2): There is no reason to think that small refiners need a larger

compliance margin than large refiners, since the distribution of toxic performance levels in a

given year is not dependent upon the size of the refinery. As a result, we believe that the

compliance margin that we have generated and will apply to the toxic performance

requirement for every refinery will be sufficient for small refiners as well as large.

(3) Refiners must provide for a level of safety margin in meeting any regulatory

requirement. Some allowance must be provided first for day-to-day test

variability and reproducibility. For a longer-term program based on an annual

or longer compliance period, over-compliance must be provided throughout a

major portion of the period to be sure that the average can be met in the

event of unforseen market, operating or other situations occurring at the end

of the compliance period. The appropriate level of compliance margin will

depend on a number of factors, i.e., testing reproducibility, benzene extraction

reliability, market trends, etc., but in no event should exceed 0.95 vol.%. The

commenter argues that the failure to provide a compliance cushion could lead

to unintended consequences, such as increased use of MTBE or reduced

production of low baseline RFG with higher baseline CG.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 5-6

Response to 6.6(A)(3): We agree that a compliance margin is appropriate for the toxics

performance requirement we are finalizing today. See response to issue 6.6(A)(1). 

However, we do not believe that our annual averaging program is highly sensitive to day-today test variability. Although test variability can be quite important when the standard in

question is established on a per-gallon basis, annual averaging has the benefit of

substantially muting the impacts of test variability on compliance; over many batches, test

variability is just as likely to produce results that are too low as results that are too high. Still,

test measurement variability combines with blending tolerances, contamination, changes in
Response to Comments

December 20, 2000

Page 69

crude composition, and other sources of variability in such a way that refiners cannot

maintain perfect control over the toxic performance levels of every one of their batches all the

time. The compliance margin that we are including in our anti-backsliding program is

intended to account for the combined effect of all this variability, and will also protect against

potential increases in the use of oxygenates or pressure to change relative production

volumes of RFG and CG. It should be noted that the deficit carryover provision in our final

rulemaking will also provide refiners the flexibility they need to comply with their baseline at

negligible cost, even in those instances where unforseen market, operating or other

situations occur at the end of the compliance period.

(B) Another reason that the proposal is too stringent is because refinery

compliance is dependent in large part on uncontrollable operating or market

circumstances that may change and interfere with refiners' ability to maintain

1998-99 baseline levels without additional controls.

(1) Overcompliance in 1998-99 is partially explained by unusual market

conditions that resulted in abnormally low benzene levels. One refiner

provides data to show that levels were abnormally low that year as part of an

operational strategy to manufacture high levels of premium gasoline. 

Because of these types of situations, refiners will not necessarily be able to

maintain the baseline levels if operating circumstances, raw material supply,

or product demands fluctuate.

Letters:

Gary Williams Energy Corporation (IV-D-3) p. 2

Silver Eagle Refining, Inc. (IV-D-18) p. 1

Response to 6.6(B)(1): Since we have switched to a toxics performance requirement for this

final rule, refiners will have more flexibility to address fluctuations in the benzene content of

fuel. But, as discussed in Chapter 7.A.3 of the Technical Support Document, we find no

reason to expect the market for benzene to change. In fact, future forecasts suggest that 

benzene consumption in the U.S. will increase over the next several years. 

Nonetheless, we are allowing a refiner to petition EPA for a permanent adjustment of

its toxics baseline. The refiner must demonstrate how circumstances during 1998-2000

materially affected the baseline toxics value determination. Because we believe that the 

changes made to this final rule - deficit and credit carryforward, compliance margin, inclusion

of a third baseline year - sufficiently consider and minimize the potential compliance burden

for those refiners that experience unusual refinery operational issues, we expect that the

number of baseline adjustments will be small. 

(2) Refiners with very low benzene levels during the baseline period are now

faced with no operating flexibility under the proposed rule. One commenter

noted that refiners with significant benzene extraction (because of favorable

market conditions) can only achieve further reductions from reformate and

catalytic cracker streams, the science of which is not well understood. 
Response to Comments

December 20, 2000

Page 70

Furthermore, one commenter noted that if the benzene market shrinks,

refiners that significantly overcomplied with the benzene standards due to

strong benzene extraction and sales may not be able to meet the very low

benzene baseline in the future. One commenter provided detailed summary

of operations at two refineries to document these concerns.

Letters:

American Petroleum Institute (IV-D-21) p. 3

Citgo Corporation (IV-D-5) p. 2-3

ExxonMobil (IV-D-16) p. 5

Sunoco, Inc. (IV-D-23) p. 1

Tosco (IV-D-41) p. 3

U.S. Department of Energy (IV-G-2) p. 2-3

Response to 6.6(B)(2): Since we have switched to a toxics performance requirement for this

final rule, refiners will have more flexibility to address fluctuations in the benzene content of

the fuel. With regard to refineries that achieved low toxics emissions levels due to benzene

extraction, we do not believe there is any basis for expecting the benzene market to change

in such a way that warrants setting a minimum toxics performance level. In fact, projections

of the benzene market suggest continued growth (see TSD, Chapter 7.A.3). Nevertheless,

as we explain in the response to 6.6(B)(1), we are allowing a refiner to petition EPA for a

permanent adjustment of its toxics baseline. 

In addition, because we are promulgating a toxics performance requirement , which is

a function of all of the fuel parameters evaluated by the Complex Model, and not a single fuel

parameter requirement (like a fuel benzene content requirement), it is not clear how we

would set such a minimum toxics emission level to account for changes in the petrochemical

market. We would have to consider each of the eight Complex Model fuel parameters

separately, and this would be complicated by the fact that the fuel parameters’ effects on

toxics emissions vary considerably. Nonetheless, we can address the issue raised by the

commenter since it is relevant, in a broad sense, to the baseline setting process. 

We do realize that even for a toxics anti-backsliding program, unusual situations may

happen which can significantly affect refinery operations, and which could cause the refinery

to be out of compliance with its requirement. To this end, we proposed and are finalizing a

one year deficit carryforward. This will allow a refinery to exceed its anti-backsliding toxics

requirement for one year. In the next year, it must make up the deficit as well as be in

compliance for that year. Additionally, though not proposed, we are also including a one year

credit carryforward. Under this provision, a refinery producing gasoline that is cleaner than

required by its toxics anti-backsliding requirement may use the overcompliance to cover any

deficit in the following year. 

(3) To overcome variations in observations of benzene, refiners might have to

change their crude oil selection decisions, sell components, or change

processing, all of which would have large financial impact. The proposed rule

does not consider these variations and the costs refiners will incur to

overcome the variations to meet a historic benzene level.
Response to Comments

December 20, 2000

Page 71

Letters:

Sunoco, Inc. (IV-D-23) p. 2

Response to 6.6(B)(3): In today’s final rule we have switched to a toxics performance

requirement which provides refineries with additional flexibility to account for variation in the

benzene content of fuel . Moreover, in determining the compliance margin of 2.5 mg/mi for

CG and 0.7 percent for RFG, we took batch variation into account by analyzing several batch

reports from several refiners which varied in terms of annual gasoline volume, geographic

location, and whether it produced CG only or CG and RFG. Finally, our analysis of refinery

reports submitted for the years 1997 and 1999 showed no significant difference in benzene

levels between these years, or for either type of gasoline, RFG or conventional. In any event,

we have added the flexibility of deficit/credit carryforward to allow refiners to address

unexpected changes at the end of the compliance period. 

(4) The demand for gasoline is estimated to grow by at least one percent over

the next twenty years. To meet this increased demand, refiners will likely

have to increase reformate throughput, which would reduce octane. To

improve octane, refiners likely will need to increase the benzene content of

gasoline.

Letters:

U.S. Small Business Administration (IV-D-26) p. 3

U.S. Department of Energy (IV-G-2) p. att

Response to 6.6(B)(4): If a refinery were to increase reformate throughput in order to help

meet a demand for gasoline production, we agree that the octane of the reformate product

would be decreased. However, we also believe the benzene produced in the reformate

would decrease. In general, as throughput in the reformate is increased, the benzene formed

in the reformate decreases. Since reformate is the gasoline refinery stream that contains the

most benzene, if reformate throughput is increased to meet a demand for more gasoline

production at a refinery, we do not believe that the benzene content of gasoline would

necessarily increase. Furthermore, since we have switched to a toxics performance

requirement for this final rule, refiners will have more flexibility to address fluctuations in the

benzene content of the fuel. Finally, because we have decided not to control incremental

volumes in today’s final rule, refinery concerns regarding increased gasoline production due

to increased demand in future years is no longer a concern.

(5) It is highly unlikely that, given the normal variability in refining and product

markets, refining operations or all product quantities will remain stable over a

period of years. As an example, one commenter provides a list of changes

that have occurred recently in the industry. Another commenter noted that

increasing RFG production or reduced volatility also could lead to the need to

replace octane and potentially increase benzene levels.

Letters:
Response to Comments

December 20, 2000

Page 72

American Petroleum Institute (IV-D-21) p. 2-3

American Petroleum Institute (IV-F-1) p. 35

Marathon Ashland Petroleum, LLC (IV-D-15) p. 4-5

National Petrochemical and Refiners Association (IV-D-33) p. 3

U.S. Small Business Administration (IV-D-26) p. 3

Response to 6.6(B)(5): Today’s final rule accounts for variability in a number of ways. The

rule finalizes toxics emission performance requirements for gasoline that require, beginning

with calendar year 2002, that a refinery’s or importer’s annual average total toxics emission

performance for its RFG not exceed its 1998-2000 baseline RFG total toxics emissions

performance. Likewise for CG, this rule will require that the exhaust toxics emissions

performance of a refinery’s or importer’s CG not exceed its 1998-2000 baseline exhaust

toxics emissions performance for CG. This baseline period is one year longer than proposed

and provides baseline values that are truer to a refiner’s normal operating mode. By

including the one additional year (2000) into the baseline, we are including the beginning of

the Phase II RFG program into the baseline which improves the baseline because it adds

data to the baseline determination which is most recently available. Including 2000 also

helps to further offset the effects of unit turnarounds by extending the baseline to a 3-year

average . We believe that the 1998-2000 baseline sufficiently accounts for changes in

refinery operations or product. Furthermore, since we have switched to a toxics performance

requirement for this final rule, refiners will have more flexibility to address fluctuations in the

benzene content of the fuel.

We do realize that even for a toxics anti-backsliding program, unusual situations may

happen which can significantly affect refinery operations, and which could cause the refinery

to be out of compliance with its requirement. To this end, we proposed and are finalizing a

one-year deficit carryforward. This will allow a refinery to exceed its anti-backsliding toxics

requirement for one year. In the next year, it must make up the deficit as well as be in

compliance for that year. Additionally, though not proposed, we are also including a one-year

credit carryforward. Under this provision, a refinery producing gasoline that is cleaner than

required by its toxics anti-backsliding requirement may use the overcompliance to cover any

deficit in the following year. 

Finally, we are providing an additional flexibility in the form of a baseline adjustment

for those refiners that can demonstrate how circumstances during 1998-2000 materially

affected the baseline toxics value determination. Thus we have provided refiners with

compliance flexibility in several forms.

We believe the changes described above will adequately address commenters’

concerns regarding variability. Our analysis projects that even with future controls and

increases in production the cost of meeting a toxics performance requirement will be

negligible. For a more detailed discussion of costs see Chapter 7.C of the Technical Support

Document, and for a more detailed discussion on increases in production (i.e., incremental

volumes) see Chapter 7.D.

(C) The proposed rule is unfair because it penalizes refiners that over-complied.
Response to Comments

December 20, 2000

Page 73

(1) The proposal penalizes refiners that have overcomplied by forcing them to

maintain that level of performance. If cleaner refineries have a lower limit

than dirtier ones, the marketplace will penalize them for being cleaner. 

Overcompliance should be rewarded, not punished. Some of these

commenters argued that could discourage sources from voluntarily going

beyond compliance under other programs for fear that EPA would use the

voluntary efforts to justify tighter standards.

Letters:

American Petroleum Institute (IV-D-21) p. 3, 9

Citgo Corporation (IV-D-5) p. 3

Marathon Ashland Petroleum, LLC (IV-D-15) p. 5

Phillips Petroleum Company (IV-D-20) p. 2-3

Sunoco, Inc. (IV-D-23) p. 1

U.S. Department of Energy (IV-G-2) p. 2-3

(2) EPA should not penalize refiners for voluntary efforts to reduce emissions. 

Commenter offers detailed comment that because its St. Croix refinery

voluntarily participated in the EPA's 33/50 Program during the proposed

baseline period, it believes that it is inappropriate to penalize refiners for

reductions in benzene achieved by these efforts.

Letters:

Amerada Hess Corporation (IV-D-14) p. 1, 6-8

Response to 6.6(C)(1) and (C)(2): The purpose of today’s action is to prevent future

increases above the current level of air toxics emissions derived from existing fuel properties. 

This toxics anti-backsliding measure will ensure that mass emission rates (in milligrams per

mile, mg/mi) of air toxics from motor vehicles do not increase while the Agency gathers

additional information for a forthcoming rulemaking in 2003-2004.

The Clean Air Act identified five air toxics in the federal reformulated gasoline

program: benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and POM. The RFG

program established a toxics emission performance standard for RFG, and an antibacksliding toxics standard for conventional gasoline based on 1990 baseline toxics levels

for each refinery. On average, refiners have overcomplied with the toxics emisisons

performance standards for both RFG and CG. Overcompliance of RFG standards resulted in

substantial toxics reductions beyond what was required by law. We have estimated

reductions in the total toxics inventories due to overcompliance of 70 thousand tons in 1996

and 40 thousand tons in 2007 (see TSD). Today’s program will ensure that these benefits

are maintained for the foreseeable future. This is important because without these antibacksliding requirements, refiners could increase the toxic emissions from their fuels up to

existing legal limits. This could happen if refineries increase benzene or aromatics to

increase octane levels, or if they change their refinery operations in reaction to unforeseen

future circumstances.
Response to Comments

December 20, 2000

Page 74

It is our belief that, in general (and absent refinery disasters or other similar, critical

events), during the baseline period, every refinery was operating to maximize profits,

considering its crude slate, operating units, product mix, marketing plan, etc. “Cleaner”

refiners must have found it profitable to be overcomplying compared to “dirtier” refiners or

they would have already been penalized by the market from being cleaner. Nevertheless, to

be fair, we are providing an additional flexibility in the form of a baseline adjustment for those

refiners that can demonstrate how circumstances during 1998-2000 materially affected the

baseline toxics value determination. 

(D) Commenters note that the effect of the MTBE, Tier 2 and HDDE rules will result

in an increase in the benzene content of fuels and thus refiners will not be able

to maintain baseline levels at no cost.

(1) Because the likely future reductions of MTBE and other oxygenates in

gasoline will result in reduced volume dilution and/or reduced octane, refiners

may need to change operations to offset these impacts. Those changes,

such as increased reformer severity, likely will increase benzene content. 

Therefore, EPA must consider the effects of oxygenate reduction on any

additional benzene control program. Some of these commenters argued that

EPA needs to use a "systems approach" to evaluate the relationship of

oxygenate reductions with benzene levels. Another commenter also noted

that ethanol can only partially compensate for the loss of octane from the

MTBE phase-out. The higher oxygen content and volatility of ethanol

precludes it from being blended at the same volume levels as MTBE.

Letters:

Amerada Hess Corporation (IV-D-14) p. 4, 9

American Petroleum Institute (IV-D-21) p. 2

Citgo Corporation (IV-D-5) p. 3

ExxonMobil (IV-D-16) p. 2, 5

Kern Oil & Refining, Inc. (IV-D-31) p. 2-4

Marathon Ashland Petroleum, LLC (IV-D-15) p. 5

Murphy Oil Corporation (IV-D-17) p. 3-4

U.S. Small Business Administration (IV-D-26) p. 3

U.S. Department of Energy (IV-G-2) p. att

Western Independent Refiners Association (IV-D-40) p. 2-3

Response to 6.6(D)(1): We did not conduct a detailed analysis of potential MTBE controls

because we are still currently working on our MTBE proposal and it would be premature to

consider the possible impacts from this effort. The primary mechanism for controlling MTBE

emissions would be to limit the use of MTBE in gasoline, and any toxics emissions impacts 

will be addressed in a separate rulemaking under the Toxic Substances Control Act (TSCA). 

This rule will be considering whether to phase-down or phase-out MTBE use. We believe it

is reasonable to defer consideration of MTBE controls to that rulemaking, which will address

the important concerns of preserving water resources, as well as any air pollution impacts,

including today’s toxics performance requirement. In addition, the EPA and the United States
Response to Comments

December 20, 2000

Page 75

Department of Agriculture jointly announced, on March, 2000, the Administration’s legislative

principles for protecting drinking water supplies, preserving clean air benefit and promoting

renewable fuels and urged Congress to take action consistent with these principles,

including providing EPA the authority significantly reduce or eliminate the use of MTBE in

gasoline.

While we have not tried to predict how controls on MTBE might affect the costs of

complying with today’s rule, we note that since we have switched to a toxics performance

requirement for this final rule, refiners will have more flexibility to address fluctuations in the

benzene content of the fuel or fluctuations in octane. 

Finally, some of these commenters argued that EPA needs to use a “systems

approach” to evaluate the relationship of oxygenate reductions with benzene levels. 

Because the Agency is currently working on potential controls on MTBE in a separate

rulemaking, we believe it is premature to conduct a detailed analysis on the potential control

of MTBE in today’s rulemaking. Rather, we believe it is more appropriate for today’s toxics

performance requirement to be addressed in the MTBE TSCA rulemaking.

(2) The new refinery processing configuration necessary to meet the Tier 2

requirements will likely require the production of higher aromatics (benzene)

gasoline to compensate for the octane losses experienced in making the

lower sulfur gasoline. Similarly, other commenters argued generally that

benzene levels will increase to compensate for octane loss from desulfurizing

FCC gasoline to meet the Tier 2 standards. Some of these commenters also

noted that to compensate for the lost octane, small refiners will increase

reformer severity (and run the platformer harder), which results in more

benzene. EPA may want to use this proposal as a means to avoid that

potential outcome, but EPA must assess the costs incurred by refiners to

maintain current benzene levels in the face of these fuel changes. Other

commenters also noted generally that to maintain baseline levels in the light

of market, operational or fuel changes, refiners may choose from several

strategies, but each option to decrease the benzene content of fuel would

require significant capital investment and increase the operating expenses of

the refiner. 

One refiner estimates that its cost of compliance will be approximately $10

million, necessary to upgrade the splitter and to add a benzene saturation

unit. Another refiner estimates that, based on changes to meet Tier II

requirements, it will need to invest an additional $35 million for a reformate

splitter and an isomerization unit to maintain baseline benzene levels. 

The DOE provides a detailed analysis and estimate of the cost impacts

associated with the no-backsliding approach given: (1) transition to low sulfur

gasoline; (2) expected near-term production increases; and (3) an MTBE ban. 

The DOE used a refinery modeling technique to develop the cost impact

estimates. The comments include an attachment that describes the study

methodology and findings. In each modeled case, the importance of octane

and reformate gasoline under any of these three changes in the overall

gasoline pool result in cost increases to maintain 1998-99 baseline benzene

levels. Moreover, the model assumes liberal increases in demand for
Response to Comments

December 20, 2000

Page 76

benzene as petrochemical feedstock, and DOE's analysis notes that more

conservative assumptions would increase the modeled cost impacts of EPA's

proposal. For the low-sulfur gasoline issue, DOE estimates that the refiners'

cost of complying with the proposed rule will be approximately 0.3 cents per

gallon. Assuming that near-term gasoline production increases at expected

levels (and assuming that those increased volumes must meet the baseline

benzene levels), the refiners' costs would increase approximately by an

additional 0.3 cents/gallon. Finally, the Department's analysis suggests that

reducing or eliminating MTBE as a fuel component will further increase the

cost of maintaining current gasoline benzene levels by 0.36 cents/gallon. 

Thus the combined effect of all three changes in the overall gasoline pool

would be an approximate one cent/gallon increase in refiners' production

costs.

Letters:

Amerada Hess Corporation (IV-D-14) p. 4, 9

American Petroleum Institute (IV-D-21) p. 2-3, 5-6

Citgo Corporation (IV-D-5) p. 3

ExxonMobil (IV-D-16) p. 2, 5

Gary Williams Energy Corporation (IV-D-3) p. 2

Marathon Ashland Petroleum, LLC (IV-D-15) p. 5

Murphy Oil Corporation (IV-D-17) p.1, 3-4

Placid Refining Company, LLC (IV-D-2) p. 2

U.S. Small Business Administration (IV-D-26) p. 3

U.S. Department of Energy (IV-G-2) p. att

Response to 6.6(D)(2): The refinery modeling overseen by the Agency for this rulemaking

predicted only negligible costs related to a toxics emissions performance baseline

requirement, despite capturing a greater amount of the overcompliance with toxic emissions. 

This situation is the result of the reduction in fuel sulfur levels which operate to reduce

emissions of VOCs and air toxics by enabling the next generation of light-duty aftertreatment

to operate effectively. Thus the refinery modeling predicted that even with potential changes

to octane and possibly benzene content, benzene and toxic emissions will not increase

above 1999 levels even after Tier 2, low-sulfur diesel fuel, and Phase II RFG. In sum,

accounting for future fuel requirements known to the Agency at this time, our regional refinery

modeling and emissions performance analysis does not forecast that on average refineries

will need to invest additional resources to comply with the new baseline requirements

finalized today. Based on our regional refinery modeling, we conclude that a toxics

performance requirement would be more appropriate for our anti-backsliding program under

202(l)(2) than the proposed benzene content standard, due in part to the potential costs

associated with a benzene content standard. The reader should refer to the TSD, Chapter

7.C for a more detailed discussion of the refinery modeling. Please see response 6.6(D)(1)

for our response regarding MTBE. 

(3) Small refiners have restricted feedstocks, limited gasoline processing

capabilities, and limited access to financing, engineering, and other

resources. To the extent operational changes are needed to maintain
Response to Comments

December 20, 2000

Page 77

baseline benzene levels, the proposed regulations may force small refiners to

either shut down or operate at production levels that may be uneconomical. 

Small refiners also may be forced to increase their dependence on outside

gasoline blendstocks which may not be available at economical prices. One

commenter also argued that small refiners do not have sufficient benzene

volumes to cost effectively sell benzene feedstock to overseas chemical

plants. One commenter also argued to meet the tighter diesel fuel sulfur

standards, hydrogen consumption in hydrotreaters will increase significantly,

resulting in the need to increase reformer severity. An increase in reformer

severity will result in increased benzene levels in gasoline. Because of these

constraints, benzene sales are not economical for small refiners. Another

commenter stated that small refiners have indicated that market changes

alone could mean a $5-10 million increase in equipment costs to meet the

lowest average benzene level from 1996-1999 versus the highest level. The

commenter argues that these cost impacts will only increase as a result of

operational changes that will be necessary to meet MTBE, desulfurization,

and MACT requirements and that may affect benzene levels.

Letters:

Gary Williams Energy Corporation (IV-D-3) p. 2-3

Kern Oil & Refining, Inc. (IV-D-31) p. 4-5

Placid Refining Company, LLC (IV-D-2) p. 2

Silver Eagle Refining, Inc. (IV-D-18) p. 1

U.S. Small Business Administration (IV-D-26) p. 3

Western Independent Refiners Association (IV-D-40) p. 2-3

Response to 6.6(D)(3): See response to 6.6(D)(2). In addition, our refinery modeling

comparing the year 1999 as a base case year to the year 2005 as the reference case year

(accounting for expected changes in fuel properties due to Phase II RFG, Tier 2 low-sulfur

gasoline and 15 ppm low-sulfur diesel fuel (based on the proposed HD07rule)) showed that

for CG, the toxics emissions are likely to remain at or below 1999 levels and that for RFG,

refiners are likely to be able to meet or exceed the new toxics baseline requirements. 

Therefore, on average we do not anticipate that benzene levels will increase significantly for

small refiners during the implementation of these future fuels programs. To help ensure that

this toxics emission anti-backsliding program is achievable for all refiners in the near term,

we are also including a deficit and credit carry forward, a compliance margin and an

expanded baseline period.

(4) One commenter estimates that the MTBE and desulfurization rules will

increase gasoline benzene content by 20% from the 1998/1999 baseline

levels.

Letters:

Placid Refining Company, LLC (IV-D-2) p. 2

Response to 6.6(D)(4): See response to 6.6(D)(1) and 6.6(D)(2).
Response to Comments

December 20, 2000

Page 78

(E) Gasoline benzene levels will be impacted by shortages in the availability of

ethanol as MTBE is phased out.

(1) Should ethanol supplies become limited due to the proposed MTBE phaseout, benzene levels will increase as the octane from ethanol will be replaced

by operating at higher reformer severities.

Letters:

Amerada Hess Corporation (IV-D-14) p. 4

Placid Refining Company, LLC (IV-D-2) p. 2

Response to 6.6(E)(1): See response to 6.6(D)(1).

(F) Small refiners subject to the interim standards for sulfur in gasoline from 2004-

2007 will likely experience an increase in gasoline benzene levels during the

interim compliance period.

(1) To meet the interim standards, small refiners will likely undercut the heavy

FCC gasoline (which is essentially benzene-free) into the distillate pool which

will proportionately increase the percentage of benzene in the gasoline pool.

Letters:

Placid Refining Company, LLC (IV-D-2) p. 1

Response to 6.6(F)(1): The refinery modeling predicted that even with potential changes to

octane and possibly benzene content, benzene and toxic emissions will not increase above

1999 levels even after Tier 2, low-sulfur diesel fuel, and Phase II RFG. In sum, accounting

for future fuel requirements known to the Agency at this time, our regional refinery modeling

and emissions performance analysis does not forecast that on average refineries will need to

invest additional resources to comply with the new baseline requirements finalized today. 

Our regional refinery modeling allowed us to conclude that a toxics performance requirement

would be more appropriate under 202(l)(2) than the proposed benzene content standard, due

in part to the potential costs associated with a benzene content standard. The reader should

refer to the TSD, Chapter 7.C for a more detailed discussion of the refinery modeling. Since

we have switched to a toxics performance requirement in today’s rule, refiners will have more

flexibility to address fluctuations in the benzene content of the fuel, because other fuel

properties may be altered in order to meet the toxics performance requirement besides

benzene. Because our refinery modeling accounted for the introduction of low-sulfur

gasoline, we do not believe that refiners will have significant costs in meeting a toxics

performance requirement during the interim period. 

6.7: Start Date
Response to Comments

December 20, 2000

Page 79

(A) EPA should implement the rule earlier than the proposed 2002 start-date.

(1) The serious public health threats associated with MSATs in urban areas and

the clear statutory mandate of the CAA warrant immediate action by the

Agency, sooner than 2002.

Letters:

Consumer Policy Institute (IV-D-8) p. 2

Response to 6.7(A): Given that this final rule is being issued late in December 2000, and

that the reporting period is the calendar year, it is not practical to implement this program

sooner than the beginning of 2002. Though it is simply an anti-backsliding program, and

refiners will easily and quickly be able to determine their baseline, there are baseline-related

issues which will take some time to figure out. Additionally, though we could start the

program early, and perhaps pro-rate baselines for that first year, there would be little or no

environmental or economic value in that exercise. The Act does not specify a start date for

the toxics program created out of the mandate of section 202(l), so we created a program

that limits toxics emissions to recent historical levels which can be implemented as soon as

practically possible. 

(B) Supports a 2002 start date.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Tosco (IV-D-41) p. 3

Response to 6.7(B): We agree with commenter.

(C) EPA should implement the rule later than the proposed 2002 start date.

(1) EPA should delay the effective date of this proposal until after 2005 when Tier

2 and MTBE requirements are completed. Only then will the costs of this

program and the magnitude of the benzene reductions be quantifiable. Other

commenters stated generally that the timing should be consistent with Tier 2

and/or MTBE implementation.

Letters:

American Petroleum Institute (IV-D-21) p. 7

Marathon Ashland Petroleum, LLC (IV-D-15) p. 7

Phillips Petroleum Company (IV-D-20) p. 4

(2) Compliance with the benzene level standard by 2002 will be problematic. 

Once baseline determinations are made, refiners need time to develop

operational plans, and perhaps some capital projects, to ensure compliance

with the new standards. One commenter suggests a lead time of at least 2
Response to Comments

December 20, 2000

Page 80

years from final promulgation of the rule, and a longer lead time of up to 4

years may be required.

Letters:

American Petroleum Institute (IV-D-21) p. 7

ExxonMobil (IV-D-16) p. 5

Phillips Petroleum Company (IV-D-20) p. 4

Response to 6.7(C)(1) and 6.7(C)(2): We are finalizing the start date as proposed. 

Because this is an anti-backsliding program, lead time is not needed to install hardware or

make operational changes. As indicated in the preamble to the final rule, refinery modeling

indicates that, on average, refineries’ toxics emissions will tend to be lower than 1999 levels

(approximating our baseline period) after Tier 2. Thus, there is no need to wait for

implementation of future controls to evaluate the achievability of these anti-backsliding

standards. 

6.8: Separate Standards for RFG & CG

(A) Supports a single pool benzene program.

(1) A single pool would not affect the level of total benzene in gasoline but would

provide refineries with much more flexibility. Otherwise, the flexibility for a

refiner to shift production depending on their own needs, market incentives or

future opt-ins to the RFG program will be very restricted.

Letters:

American Petroleum Institute (IV-D-21) p. 8

Citgo Corporation (IV-D-4) p. 5

Response to 6.8(A)(1): The commenter(s) specifically raises the issue of separate antibacksliding requirements for RFG and CG. It is true that setting a single standard for the

benzene content of all gasoline, whether RFG or CG, would not allow the total amount of

benzene in gasoline to increase above 1998 - 2000 levels. However, doing so could result in

increases in RFG fuel benzene content, which would result in increased benzene emissions

in RFG areas. We have have set separate anti-backsliding baselines for RFG and CG

because we have determined that separate standards represent the greatest degree of

control achievable in the short term at negligible cost. A single pool for control of toxics

emissions under our anti-backsliding program would not represent the greatest degree of

control achievable.

6.9: Incremental Volumes

(A) Supports the use of the 0.95% volume requirement for incremental volumes of

RFG above baseline levels.
Response to Comments

December 20, 2000

Page 81

(1) Removing additional benzene from incremental RFG production does not

make economic sense and will result in added cost to refiners. Some

commenters noted that subjecting incremental RFG production to baseline

levels would penalize refiners that have overcomplied. A 0.95% by vol.

requirement will encourage incremental RFG production where needed and

provide needed flexibility for refiners to respond to increased RFG demand

and avoid supply disruptions. One commenter added that, with gasoline

demand increasing, more stringent standards on incremental volumes would

likely have a significant negative impact on the market. One of the

commenters also suggested that, because incremental volumes will be

subject to Phase II RFG, a simpler solution may be to exempt incremental

volumes from this rule.

Letters:

American Petroleum Institute (IV-D-21) p. 8

British Petroleum (IV-D-18) p. 2

ExxonMobil (IV-D-15) p. 7

Marathon Ashland Petroleum, LLC (IV-D-14) p. 7

National Petrochemical and Refiners Association (IV-D-33) p. 7

Phillips Petroleum Company (IV-D-20) p. A-3

Sunoco, Inc. (IV-D-23) p. 2

Response to 6.9(A)(1): The use of the current 0.95 vol% benzene requirement for

incremental volumes of RFG above baseline volumes is equivalent to excluding incremental

volumes from this rulemaking. As described in the preamble, we have in fact determined that

it is appropriate to exclude incremental volumes.

According to our analysis of the relationship between fuel benzene content and increasing

gasoline production volumes, as summarized in the Technical Support Document, we believe

that incremental volumes will exhibit very small, if any, increases in fuel benzene content. As

a result, we would not expect that the application of our anti-backsliding requirement to

incremental volumes would result in added cost to refiners. However, since our analysis

focused on fuel benzene content only, and since it did not take into account the potential for

increased gasoline imports to meet growth in gasoline consumption over time, we cannot be

confident that the toxics emissions performance levels of gasoline will not deteriorate as

production volumes increase above baseline levels. If the toxics emissions performance

deteriorates with increasing production, our standard could impose significant costs on

refiners by requiring them to control the toxics performance of these incremental volumes. 

Because we do not believe that a program that imposes these costs is achievable in the near

term, and because we do not want to create a disincentive for RFG producers to increase

production, we are excluding these incremental volumes from today’s rule. These

incremental volumes, however, will remain subject to the existing RFG standards in 40 CFR

§80.41.

Concerning the comment that subjecting incremental RFG production to baseline levels

would penalize refiners that have overcomplied, please see our response to Issue 6.6(C). 
Response to Comments

December 20, 2000

Page 82

(B) Incremental CG should be limited to original 1990 CG industry average benzene

levels.

(1) Such an approach is consistent with the existing regulations and is consistent

with the approach suggested by many commenters for RFG. One commenter

added that, with gasoline demand increasing, more stringent standards on

incremental volumes would likely have a significant negative impact on the

market.

Letters:

American Petroleum Institute (IV-D-21) p. 8

British Petroleum (IV-D-18) p. 2

ExxonMobil (IV-D-15) p. 7

National Petrochemical and Refiners Association (IV-D-33) p. 8

Phillips Petroleum Company (IV-D-20) p. A-3

Response to 6.9(B)(1): For the reasons stated in the preamble and in our response to Issue

6.9(A)(1), on the basis of the information available to us at this time we cannot guarantee that

the toxics emission performance levels of incremental volumes will not deteriorate. This

holds true for CG as well as RFG. As a result, we have determined that the exclusion of

incremental volumes from our anti-backsliding program should apply to CG as well as RFG

to ensure that today’s rule is achievable in the near term.

(C) Incremental volumes should be subject to national average benzene levels

(0.66% RFG and 1.11% CG).

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Amerada Hess Corporation (IV-D-13) p. 3, 8

Response to 6.9(C)(1): We have decided to exclude incremental volumes from this rule,

rather than applying a separate standard to these volumes. We believe this approach is the

most reasonable way to avoid imposing potentially significant costs on refiners and ensure

that today’s standards are achievable in the near term. 

(D) For incremental volumes of CG and RFG, EPA should use the industry-wide

average for the baseline period selected in the final rule.

(1) Such an approach will provide needed flexibility while maintaining the intent

of the anti-backsliding approach. If EPA does not take this approach to

incremental volumes, refineries with the highest baselines will have the

greatest incentive to increase production at the lowest cost.
Response to Comments

December 20, 2000

Page 83

Letters:

Chevron (IV-D-34) p. 1

Response to 6.9(D)(1): See our response to Issue 6.9(C). We believe the exclusion of

incremental volumes from this rule addresses commenter’s concern regarding disincentives

to increase production.

(E) EPA should propose a single weighted annual standard rather than 2 separate

compliance periods and compliance levels (one applicable to baseline

production and another applicable to incremental production).

(1) Most commenters suggested this for both RFG and CG. Commenters

generally provided no further supporting information or detailed analysis,

although one commenter supported this approach only for CG and provided

an example of how this approach would work for CG.

Letters:

American Petroleum Institute (IV-D-21) p. 8

ExxonMobil (IV-D-15) p. 7

National Petrochemical and Refiners Association (IV-D-33) p. 8

Phillips Petroleum Company (IV-D-20) p. A-3

Response to 6.9(E)(1): As discussed in our response to Issue 6.8, we have determined that

our anti-backsliding program should apply separately to RFG and CG. However, we agree

that within these two pools of gasoline, our anti-backsliding program should set a single

standard rather than two standards, one applicable to baseline volumes and another to

incremental volumes. 

Since we have determined that our program should exclude incremental volumes, it was

necessary to adjust the compliance calculations accordingly without requiring refiners to

identify the specific volumes of their gasoline which might be labeled the incremental

volumes. Otherwise there would in fact be separate standards applicable to baseline and

incremental volumes. As described in the Technical Support Document, we have finalized a

compliance procedure in which the existing standards for RFG or CG, as applicable, are

volume-weighted with a refinery's own baseline toxics performance levels to obtain the

compliance baseline applicable to all future production. This procedure effectively excludes

incremental volumes from the compliance calculation while avoiding separate standards for

baseline and incremental volumes.

(F) Additional volumes (or gasoline produced by importers/foreign producers

should meet the most stringent of: the individual refiner's 1998-99 baseline or

1998-99 national average baseline.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:
Response to Comments

December 20, 2000

Page 84

Bluewater Network (IV-D-29) p. 1-2

Response to 6.9(F)(1): See our response to issue 6.9(C).

6.10: Appropriate Baseline Period

6.10.1: Proposed 1998-99 Baseline Period

(A) Expressed support for the proposed baseline period.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Commonwealth of MA DEP (IV-D-13) p. 1

Response to 6.10.1(A): While a 1998-1999 baseline period was proposed, after further

consideration, we believe that a baseline period of 1998-2000 is more appropriate because it

includes the most recent gasoline production of a refinery. A three-year baseline period also

averages out the effects on gasoline from operational irregularities and changes such as

equipment turnarounds. 

(B) Expressed opposition to the proposed baseline period.

(1) The arbitrary choice of the 1998/1999 period penalizes those refiners who,

because of various operating or market conditions during those years, had

lower benzene levels than would otherwise be normal or reasonable. (See

related comments under Issue 6.6.) A number of these commenters

proposed alternative baseline periods (see Issue 6.10.2). One commenter

added that the choice of a 1998-99 baseline year restricts small refiners and

does not allow the flexibility small refiners need to operate efficiently.

Commenter points to conflicts with recent design changes at its plant and the

likely restrictions on blend stock mixes as adverse effects caused by use of

the 1998-99 baseline period.

Letters:

Amerada Hess Corporation (IV-D-14) p. 1, 3, 6

Citgo Corporation (IV-D-5) p. 1

Countrymark Cooperative, Inc. (IV-D-35) p. 2

Gary Williams Energy Corporation (IV-D-3) p. 2

Phillips Petroleum Company (IV-D-20) p. A1-A2

Response to 6.10.1(B)(1): As indicated in the proposal, we believe, that in general, refiners

were operating during the proposed baseline period at a benzene level that was the best for

them at the time. Many of the refiners with the lowest baseline benzene levels remove

benzene from their gasoline pool by extracting it and selling it to the petrochemical market.

This extraction technology is quite costly, and is not likely to be underutilized. Additionally,
Response to Comments

December 20, 2000

Page 85

we do not expect a downturn in the petrochemical market’s need for benzene as a feedstock. 

Thus, those refiners that have low benzene levels (mostly those with extraction capability) will

likely be able to continue extracting benzene, thus maintaining their low baseline benzene

levels. The form of the standard finalized today, a toxics performance standard, may be

more flexible for most refiners than the proposed benzene standard. Finally, the start of the

Tier 2 gasoline sulfur program should provide yet additional flexibility in meeting today’s

toxics requirement, as our refinery modeling predicts that, on average, toxics emissions after

start of Tier 2 should be lower than during the baseline period.

With regard to the small refiner comment, we do not have provisions for small refiners

because we determined that this rule does not affect small refiners differently than it affects

all other refiners. We have provided a number of flexibilities, including deficit and credit

carryforward, which are available to all refiners. Additionally, we believe that adding the year

2000 to the baseline period (now, 1998-2000) helps to smooth out year-to-year

inconsistencies at the refinery, due to operational factors, marketing, etc. We have also

included a provision which allows a refiner to petition for a different baseline for its refinery in

certain situations.

(2) The proposed baseline period ignores the impact of compliance with recently

promulgated and pending fuels regulations which will impact the benzene

concentration in the gasoline pools. (See related comments under Issue 6.6.)

Letters:

Countrymark Cooperative, Inc. (IV-D-35) p. 2

Murphy Oil Corporation (IV-D-17) p. 2

Response to 6.10.1(B)(2): We disagree that the proposed baseline period, or the baseline

period finalized today, ignore the recently promulgated rules (presumably, Tier 2 gasoline

sulfur). We used refinery modeling results in our analysis for this rule which showed that, on

average, toxics emissions after the start of the gasoline sulfur program will be lower than in

the baseline period (for the refinery modeling work, 1999). Thus, it is likely that by virtue of

complying with the gasoline sulfur rules, refiners may find it easier to comply with today’s

toxics requirements. It is premature at this time to consider the impact on toxics performance

of the upcoming MTBE rule because we do not know what that rule will look like.

(3) The proposed baseline period penalizes those refiners who have optimized or

revised their operation in such a manner that has inadvertently increased

gasoline pool benzene levels, such as changes in availability of feedstock or

purchased gasoline blendstocks. One commenter's facility is no longer able

to procure the same lower benzene content blendstocks that it purchased in

1998-1999.

Letters:

Amerada Hess Corporation (IV-D-14) p. 1-2

Response to 6.10.1(B)(3): We expanded the baseline period to encompass three years

instead of two. The three year baseline period should help to smooth out operational
Response to Comments

December 20, 2000

Page 86

irregularities and bring the baseline closer to the most recent operational year. And, as

explained above, the gasoline sulfur program will likely cause toxics emissions levels to

decrease beyond those of the baseline period, thereby further ensuring that the costs

associated with this rule will be negligible. Additionally, the switch from the proposed

benzene standard to today’s finalized toxics standards should provide more flexibility for a

refiner.

(4) The proposed baseline period penalizes those refiners who supplied

Oxygenated Fuels Program Gasoline to States as mandated by EPA due to

certain States' designation as CO non-attainment areas. The baseline also

penalizes any refiner who has recently completed capital project work to

improve refinery operations in such a way that may increase overall gasoline

pool benzene. In addition, the proposed baseline penalizes those refiners

that ran without downtime of benzene extraction equipment during the period. 

When these extraction units are shut down for required maintenance, the

refiner will not be able to match baseline benzene levels.

Letters:

Amerada Hess Corporation (IV-D-14) p. 2-3, 6-7

Response to 6.10.1(B)(4): We agree that the use of oxygenate reduces fuel benzene levels

due to dilution. However, considering the switch from the proposed fuel benzene content

standard to a toxics performance standard, and the compliance margin and other flexibilities

provided as part of today’s rule, we believe that refiners have sufficient flexibility to address

these types of changes. Nonetheless, we have provided limited provisions for baseline

adjustments under today’s rule. 

(5) If refiners met more stringent benzene levels in 1999-2000, EPA should use

that period as the point of reference to ensure that there is no backsliding

from current benzene levels.

Letters:

Clean Air Network, et al (IV-D-38) p. 3

Response to 6.10.1(B)(5): We have expanded the baseline period to include the year 2000,

creating a baseline period that spans 1998-2000. We did not choose this period to capture

the lowest average benzene levels of refiners. Rather, we chose this period to encompass

recent activity. The period 1999-2000 may have been the lowest average benzene period for

some refiners, but certainly not all refiners. We chose the baseline period for this antibacksliding rule to ensure that the standard would be achievable in the near term. 

Additionally, we included 2000 data to reflect the most recent operations and extended the

baseline period to three years to account for operational irregularities and changes.

(C) EPA should revise section 80.690(c)(2)(i) to delete the term "annual."

(1) The benzene baseline is a volume-weighted average over a 24-month period,

not an annual average.
Response to Comments

December 20, 2000

Page 87

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 16

Response to 6.10.1(C)(1): We have taken commenter’s suggestion into account in

modifying the regulations to the new toxics performance approach .

6.10.2: Alternative Baseline Periods and Adjustments

(A) Several years of data should be used to establish a baseline in order to account

for the many factors that influence a refinery's gasoline volume, benzene level,

and RFG/CG ratio from year to year.

(1) A longer timeframe, such as 1996-1999 or 1997-1999 at a minimum, is

preferred because a longer period would be more representative of actual

refinery operations over time, and less influenced by short-term shifts in

operations or markets, than a two-year period. This approach would reduce

the need to petition for an alternative. One commenter specifically

recommended a 1996-99 baseline period because that period: covers the

RFG Phase I period with exclusion of the first transition year (1995); covers a

4-year span that is likely to include and recognize most major turnarounds at

refineries and at least allows their impact to be averaged over four years; and

is consistent with the anti-dumping blendstock controls.

Letters:

American Petroleum Institute (IV-D-21) p. 7

British Petroleum (IV-D-19) p. 2

ExxonMobil (IV-D-16) p. 7

National Petrochemical and Refiners Association (IV-D-33) p. 7

Tosco (IV-D-41) p. 3

(B) Opposes an individual refiner/importer baseline, but if EPA determines one is

necessary, it should include as many years as practical.

(1) One commenter suggested a four-year baseline (1996-1999) which includes

operational fluctuations at any given refinery, while another commenter

suggested using the entire RFG Phase I period (1995-1999). This approach

would reduce the need for a refiner to petition for a different baseline period if,

during a portion of the baseline period, operations were significantly different

from average. 

Letters:

Citgo Corporation (IV-D-5) p. 4

Phillips Petroleum Company (IV-D-20) p. A1-A2
Response to Comments

December 20, 2000

Page 88

(2) Commenter suggests a 3-year baseline period from 1998-2000. Inclusion of

the year 2000 into the baseline period will incorporate recent operational

history and help compensate those refiners that have undergone recent

operational changes.

Letters:

Amerada Hess Corporation (IV-D-14) p. 3, 8

Response to 6.10.2(A)(1), (B)(1), and (B)(2): We are finalizing a three-year baseline

period, encompassing the years 1998, 1999 and 2000. This baseline period, which is one

year longer than the baseline period we proposed, provides baseline values which are truer

to a refinery’s “normal” operating mode. We believe that including 2000, precisely because

it is a Phase II RFG year, improves the baseline because it adds data to the baseline

determination which is the most recent available. Including 2000 also helps to further offset

(by virtue of a 3-year average versus a 2-year average) the effects of unit turnarounds at the

refinery. At the same time, we do not expect significant differences, on average, between a

baseline established using the 2-year averaging approach and one developed using the 3-

year approach. However, we believe that for an individual refinery, the 3-year averaging

approach provides that refinery with a more robust baseline. Finally, given that compliance

with this rule is unlikely to require any capital improvements or operational changes by

refiners to achieve its goals, and since refiners will have the 2000 data, we believe this data

should be included in the baseline determination.

(C) A refiner should be allowed to adopt as its baseline either their average

benzene level in 1998-99 or their highest average level from the last five years. 

Or the baseline choice could be between the 1998-99 average or an average

based on any two years of the refiner's choice from the last five years.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Countrymark Cooperative, Inc. (IV-D-35) p. 3

(2) Offering refiners, especially small refiners, a baseline choice might provide

some flexibility. However, this would not fully address the likely future

changes in the baseline beyond 2000 that will be necessary because of other

fuel control regulations.

Letters:

U.S. Small Business Administration (IV-D-26) p. 4

(3) Commenter prefers a small refiner exemption for Phase I, but in the absence

of an exemption believes that this type of baseline flexibility could provide

some flexibility for small refiners in the interim period before 2004.

Letters:
Response to Comments

December 20, 2000

Page 89

Gary Williams Energy Corporation (IV-D-3) p. 4

Response to 6.10.2(C)(1), (C)(2), and (C)(3): We disagree that a refinery’s baseline should

be its highest level during any time period, or the refiner’s choice of any two years (which

likely would result in the highest average level), even under a toxics performance standard. 

We set a uniform baseline period because it sets a standard, based on the most recent

activity for every refiner, which likely was the most economical manner in which to run the

refinery. Additionally, we have not included small refiner provisions because we do not

believe small refiners are affected differently by today’s rule than other refiners. However, we

have included a provision which allows a refiner to petition for an alternative baseline for its

refinery in certain situations.

(D) Opposes inclusion of the years 1995 and 2000 in the baseline.

(1) Commenters oppose use of these years because they were RFG transition

years, and therefore are not representative of actual refinery operations over

time.

Letters:

American Petroleum Institute (IV-D-21) p. 7

ExxonMobil (IV-D-16) p. 7

(E) Opposes the use of the year 2000 in the baseline because, since the time EPA

published its proposed rule, some refiners may choose to modify data for the

final quarter of the year 2000.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Phillips Petroleum Company (IV-D-20) p. A-2

Response to 6.10.2(D) and (E): We believe that including 2000, precisely because it is a

Phase II RFG year, improves the baseline because it adds data to the baseline determination

which is the most recent available. Including 2000 also helps to further offset (by virtue of a

3-year average versus a 2-year average) the effects of unit turnarounds at the refinery. While

transition year issues were probably significant in 1995 at the start of the RFG and antidumping programs, we believe that the switch to the Phase II RFG requirements was less

significant, in part because of the familiarity with the regulations and the production of fuels

even before 2000 that met the Phase II standards. For conventional gasoline, transition is

not an issue because the baseline fuel is the same, only the emissions, by virtue of the

Phase II Complex Model, are different. We are not concerned about refiners modifying data

for the final quarter of 2000 because this rule will not be issued until its court-ordered

deadline of December 20, 2000 and it is our understanding that most operating plans for

December have been finalized much earlier. We do not believe refiners would (or could)

significantly modify their operations for 11 days in order to affect a baseline determined over

a 3-year period.
Response to Comments

December 20, 2000

Page 90

(F) Commenter proposes a baseline using the 2-year period following the first year

in which a refinery meets the Tier 2 standards.

(1) Doing so will assure that the goals of the proposed rule and the Tier 2

standards will be met in the most efficient and fair means possible.

Letters:

Murphy Oil Corporation (IV-D-17) p. 2

Response to 6.10.2(F)(1): We do not agree with this comment. The toxics baseline after a

refinery meets the Tier 2 standards will likely be more stringent than a baseline determined

for the baseline period finalized today. As discussed in the preamble, refinery modeling

indicates that toxics emissions after the start of the gasoline sulfur program are, on average,

expected to be lower than during the 1998-2000 baseline period. Additionally, we do not

believe it would be appropriate nor practical from an enforcement point-of-view, for the

purposes of this anti-backsliding rule, to have refineries subject to the rule at different times. 

If we were to implement such a rule, we likely would have to consider interim toxics

standards for those not immediately subject to their baseline standard. As part of the 2004

rulemaking, we will likely consider whether further changes to today’s rule are appropriate

given implementation of Tier 2 and other programs.

(G) Commenter suggests that EPA keep the original 1990 refinery baseline

numbers derived from the Anti-dumping Regulation in Subpart E.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Countrymark Cooperative, Inc. (IV-D-35) p. 3

Response to 6.10.2(G): We disagree with this comment. Refineries have demonstrated

that, for at least some of them, standards beyond the 1990 levels are achievable even in the

near term, considering cost, lead time and other factors. In some cases, however, a refinery

did not overcomply with their anti-dumping baseline. For these refineries, their 1998-2000

baseline will be the same as their 1990 anti-dumping standard.

(H) EPA should allow certain baseline adjustments.

(1) First, for those refiners who supplied OPRG during the baseline period to

those control areas that no longer require high oxygen fuel, EPA should allow

refiners to back out the oxygenate dilution effect associated with oxygenate

blending beyond the 2.0% wt. required by the Federal RFG program.

Letters:

Amerada Hess Corporation (IV-D-14) p. 3-4, 8
Response to Comments

December 20, 2000

Page 91

(2) Second, if refiners began capital projects before the proposal that could affect

benzene levels, EPA should allow the refiners to factor in the impact of these

projects in determining the baseline.

Letters:

Amerada Hess Corporation (IV-D-14) p. 4, 8

(3) Third, EPA should allow refiners to include the effects of turnarounds on the

1998/1999 benzene baseline determination. Refiners operate their process

units on 4-5 year maintenance cycles; and many did not conduct any major

turnaround activities during the 1998-1999 baseline period.

Letters:

Placid Refining Company, LLC (IV-D-2) p. 3

(4) Fourth, in determining 1998-99 benzene levels, the rule should allow small

refiners to back out blendstocks and oxygenates purchased solely for antidumping or other regulatory compliance.

Letters:

Silver Eagle Refining, Inc. (IV-D-18) p. 1-2

Response to 6.10.2(H): See response to Issue 6.10.3(A).

6.10.3: Petitions for Alternative Baseline

(A) Refiners should be allowed to petition for a different baseline period if, during a

portion of the baseline period, operations were significantly different from

normal.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

American Petroleum Institute (IV-D-21) p. 7

British Petroleum (IV-D-19) p. 2

ExxonMobil (IV-D-16) p. 7

National Petrochemical and Refiners Association (IV-D-33) p. 7

Response to 6.10.3(A): In general, we are not allowing baseline adjustments under this rule,

as were allowed under anti-dumping. The toxics baselines of this rule are based on actual

data – refinery modeling is not being used to estimate the quality or quantity of gasoline

during the baseline period. Nonetheless, we have provided limited provisions for baseline

adjustments under today’s rule. 

6.11: Flexibility Provisions
Response to Comments

December 20, 2000

Page 92

6.11.1: 1- or 2-year Compliance Period 

(A) EPA should consider a two-year average for compliance purposes.

(1) Commenter makes clear, however, that neither this approach nor a one-year

deficit carryover option provides adequate protection for small refiners.

Letters:

Gary Williams Energy Corporation (IV-D-3) p. 4

(2) Commenter provides no further supporting information or detailed analysis.

Letters:

Countrymark Cooperative, Inc. (IV-D-35) p. 3

Response to 6.11.1(A): See response to Issue 6.11.2(B).

(B) A one-year averaging/compliance period is preferred provided that a refiner

would be allowed to make up any deficit and be in compliance the following

year.

(1) Refiners should also be allowed to carry-over any benzene credit to the

following year, which could be used to demonstrate compliance. Most of

these commenters added that, absent any deficit/carryover provision, a twoyear compliance period is preferred.

Letters:

American Petroleum Institute (IV-D-21) p. 8-9

British Petroleum (IV-D-19) p. 2

Citgo Corporation (IV-D-5) p. 4

ExxonMobil (IV-D-16) p. 6

Response to 6.11.1(B)(1): See response to Issue 6.11.2(B).

6.11.2: 1-year Carryover Option 

(A) Opposes a one year deficit carry-over provision.

(1) A one-year standard is more protective of human health and the environment

and is a long enough averaging period for refiners to account for production

fluctuations.

Letters:

Bluewater Network (IV-D-29) p. 2
Response to Comments

December 20, 2000

Page 93

(B) Supports a one-year deficit carry-over provision.

(1) Commenter provides no further supporting information.

Letters:

Amerada Hess Corporation (IV-D-14) p. 3, 8

(2) Such a provision allows a refiner the opportunity to correct a problem that

occurs unexpectedly toward the end of a year.

Letters:

American Petroleum Institute (IV-D-21) p. 8-9

Citgo Corporation (IV-D-5) p. 4

Marathon Ashland Petroleum, LLC (IV-D-15) p. 7-8

National Petrochemical and Refiners Association (IV-D-33) p. 9

Tosco (IV-D-41) p. 3

(3) Moreover, commenters supported a program that would allow a refiner to

carry-over credits as well as deficits to year two. The net result would be the

same as benzene levels remain at baseline levels for any two year period, but

more flexibility is granted to refiners.

Letters:

American Petroleum Institute (IV-D-21) p. 8-9

British Petroleum (IV-D-19) p. 2

Citgo Corporation (IV-D-5) p. 4

ExxonMobil (IV-D-16) p. 6

Marathon Ashland Petroleum, LLC (IV-D-15) p. 8

Phillips Petroleum Company (IV-D-20) p. A-2

(4) IF EPA does not provide a deficit carry-over provision, then a two-year

compliance period is necessary to provide flexibility and EPA also should

include a benzene trading program for refiners.

Letters:

ExxonMobil (IV-D-16) p. 6

(5) Although generally supportive, one commenter notes that such a provision (or

a 2-year compliance period) provides only a very minimal safety net because

of the more stringent operating levels required for offset.

Letters:

Gary Williams Energy Corporation (IV-D-3) p. 4
Response to Comments

December 20, 2000

Page 94

(6) One commenter argued that the carry-over should be allowed for every period

even if used in the prior period, so long as the deficit from the prior period has

been fulfilled.

Letters:

Phillips Petroleum Company (IV-D-20) p. A-2

Response to 6.11.2(A) and (B): In the NPRM we discussed compliance periods of varying

length different from the proposed single calendar year compliance period. We believe a

one-year compliance period is consistent with the compliance periods of other gasoline

programs (and thus represents minimal additional reporting burden for refiners and

importers), and it is short enough that temporal variations in toxics emissions are minimized. 

For these reasons, we are finalizing a one-year compliance period as proposed.

We do realize, however, that even for an anti-backsliding program, unusual situations may

happen which can significantly affect refinery operations, and which could cause the refinery

to be out of compliance with its requirement. To this end, we proposed and are finalizing a

one-year deficit carryforward. This will allow a refinery to exceed its anti-backsliding toxics

requirement for one year. In the next year, it must make up the deficit as well as be in

compliance for that year. Additionally, though not proposed, we are also including a one-year

credit carryforward. Under this provision, a refinery producing gasoline that is cleaner than

required by its toxics anti-backsliding requirement may use the overcompliance to cover any

deficit in the following year. Because we are also providing a toxics performance standard

compliance margin, overcompliance will be creditable for purposes of a credit carryforward

only to the extent that it is overcompliant beyond the compliance margin. The

overcompliance credits may not be traded to another company, and they expire at the end of

the next calendar year. Thus we have provided refiners with compliance flexibility in several

forms.

6.11.3: Trading Program 

(A) Commenter opposes a credit and trade program.

(1) The commenter argued that a credit program provides no environmental or

public health benefit.

Letters:

Bluewater Network (IV-D-29) p. 2

(2) Although credit programs are established to provide flexibility, in practice they

can cause unfair competitive advantage. This has occurred with the oxygen

credit program when Gulf Coast refiners have used oxygen credits generated

from ethanol use in the Midwest. A refinery-specific average with a

compliance margin would enable refiners to comply and would provide equity

among refiners.

Letters:
Response to Comments

December 20, 2000

Page 95

Sunoco, Inc. (IV-D-23) p. 2

RESPONSE to 6.11.3(A)(1) and (A)(2): In the NPRM, we discussed the possibility of

including another flexibility in the form of a credit trading program. Comments about this

option were mixed. Some refiners supported such a program, and offered other suggestions

to enhance or clarify the program. At least one refiner did not support such a program,

saying it would provide an unfair competitive advantage. Other industry commenters were

unsure of the actual implementation and feasibility of the program, given the unequal

baselines among refiners. Additionally, a trading program could result in gasoline quality

shifts from area to area. The goal of this anti-backsliding program is to maintain gasoline

quality (with respect to toxics emissions) at the refinery level; we do not expect geographic

gasoline quality shifts as a result of this program. Thus, because of these implementation,

feasibility and anti-competitive concerns, and because of the many other compliance

flexibilities provided in today’s program, we are not including a credit program as part of this

rulemaking.

(B) Commenter supports a credit and trade program.

(1) Such a program would allow refiners additional flexibility in meeting the

proposed standard and thus would be beneficial. Some commenters stated

that the program would reward those refiners who can reduce benzene levels

below the baseline. One commenter noted that credits could be separately

traded in RFG and CG categories, with the net effect of no increase in overall

benzene. One commenter, although generally supportive, raised concerns of

fairness in that those refiners with the highest baselines may most easily

generate benzene credits.

Letters:

Amerada Hess Corporation (IV-D-14) p. 3, 8

American Petroleum Institute (IV-D-21) p. 9

British Petroleum (IV-D-19) p. 2

Citgo Corporation (IV-D-5) p. 4

ExxonMobil (IV-D-16) p. 6

Marathon Ashland Petroleum, LLC (IV-D-15) p. 7-8

Phillips Petroleum Company (IV-D-20) p. 5, A-3

Placid Refining Company, LLC (IV-D-2) p. 3

Response to 6.11.3(B)(1): See response to 6.11.3(A)

(2) A credit program in conjunction with a standard based on a national average,

but set slightly higher than the 1998-99 industry average baseline, would

insure that no new construction is required and alleviate the concerns of small

refiners.

Letters:

Koch Petroleum Group (IV-D-36) p. 1
Response to Comments

December 20, 2000

Page 96

Response to 6.11.3(B)(2): See response to 6.11.3(A)

(3) Such a program would be beneficial to small refiners only if they were able to

bank credits for any periods which were under the benzene baseline before

the rule's effective date.

Letters:

Gary Williams Energy Corporation (IV-D-3) p. 4

Response to 6.11.3(B)(3): See response to 6.11.3(A)

(4) EPA should consider giving added value to credits generated below the

national average benzene levels for CG and RFG.

Letters:

Citgo Corporation (IV-D-5) p. 4

Response to 6.11.3(B)(4): See response to 6.11.3(A)

(C) The RFG benzene credit trading program should be extended to the antibacksliding gasoline benzene program.

(1) It seems unreasonable for a benzene credit trading program to exist to

facilitate compliance with a maximum 0.95 vol% annual average for RFG

without applicability to a new program with a more stringent standard.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 8

Response to 6.11.3(C)(1): See response to 6.11.3(A)

(D) Even absent a trading program, EPA should allow cumulative banking of

benzene credits for a refiner's own use.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Countrymark Cooperative, Inc. (IV-D-35) p. 3

Response to 6.11.3(D)(1): Today’s rule contains a one-year credit carryforward provision

applicable to a refinery or aggregate of refineries. Under this provision, a refinery or an

aggregate may exceed (i.e., be cleaner than) its RFG or CG standard in one year, and use

the credit thereby created to offset a deficit the next year. This provision applies separately

to RFG and CG, and cannot be applied to other refineries or aggregates. We limited the

credit carryforward to one year, the same as the proposed and also finalized deficit
Response to Comments

December 20, 2000

Page 97

carryforward provision. As discussed in the NPRM, a one-year compliance period is

consistent with the compliance periods of other gasoline programs (and thus represents

minimal additional reporting burden for refiners and importers), and it is short enough that

temporal variations in toxics emissions are minimized.

6.11.4: Hardship Waiver

(A) Opposes provision for refiners to petition for economic hardship waiver.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

American Petroleum Institute (IV-D-21) p. 7

RESPONSE to 6.11.4(A): In general, because this is an anti-backsliding rule, and not a

standard requiring additional reductions in emissions, hardship should be limited. We are,

however, adopting a provision permitting a refiner to seek a temporary waiver from the toxics

anti-backsliding requirements in certain circumstances. Such a waiver will be granted at

EPA’s discretion. Under this provision, a refiner may seek permission to exceed its toxics

anti-backsliding requirements based on the refiner’s inability to produce complying gasoline

because of extreme and unusual circumstances outside of the refiner’s control that could not

have been avoided through the exercise of due diligence. This provision is similar to a

provision in EPA’s RFG and gasoline sulfur regulations. It is intended to provide refiners

limited relief in unanticipated circumstances that cannot be reasonably foreseen at this time

or in the near future. The conditions for obtaining such a waiver are similar to those in the

RFG regulations. These conditions are necessary and appropriate to ensure that any

waivers granted are limited in scope, and that a refiner does not gain an economic benefit

from a waiver. Therefore, a refiner seeking a waiver must show that the waiver is in the

public interest, that the refiner was not able to avoid the nonconformity, that it will make up,

where practicable, the air quality detriment associated with the waiver, that it will pay back

any economic benefit from the waiver, and that it will meet its toxics anti-backsliding

requirements as expeditiously as possible. The refiner must also show that it will be unable

to meet its toxics anti-backsliding requirements even considering the deficit and credit

carryforward flexibility provisions included in today’s program.

(B) Sec. 80.775 in the proposed rule, which provides for a temporary waiver to

distribute non-conforming fuel, makes no sense because the proposed

benzene average would be an annual average.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Koch Petroleum Group (IV-D-36) p. 4

RESPONSE (6.11.4(B)): We agree with commenter that the language of the proposed

section 80.775 is awkward when applied to an annual average standard. Nonetheless, we

believe it is important to provide this type of flexibility in the toxics program we are
Response to Comments

December 20, 2000

Page 98

promulgating today, because it is possible that certain events (as specified in section 80.775)

could cause a refiner to significantly exceed its annual average standard by an amount which

cannot be remedied by the refiner the next year (deficit carryforward). Thus we are retaining

this provision with minor modification to the language to better fit the toxics program

promulgated today.

(C) Supports a hardship waiver, at least for small refiners.

(1) Commenter provides no further detailed analysis.

Letters:

Silver Eagle Refining, Inc. (IV-D-18) p. 2

Response to 6.11.4(C): See response to Issue 6.11.4(A)

6.11.5: Aggregation of Refineries

(A) Commenter supports additional flexibility by allowing multi-refinery refiners

and importers the choice of aggregating refineries to determine compliant

benzene baseline level for both RFG and CG individually.

(1) The overall benzene concentrations will be maintained while providing

needed flexibility to maintain and/or increase both RFG and conventional

gasoline.

Letters:

British Petroleum (IV-D-19) p. 2

Response to 6.11.5(A)(1): We agree with the commenter that the ability of multi-refinery

refiners to aggregate baselines for compliance is a flexibility. This flexibility is already

provided through the anti-dumping program. Because today’s toxics program is based on a

baseline period of 1998-2000, and because most refiners who have chosen to comply on an

aggregate basis did so during this time period, we are requiring them to also comply on the

same aggregate basis for this program.

6.11.6: Other Flexibility Options 

(A) EPA should allow refiners to include the effects of turnarounds or other

circumstances on the benzene compliance standard.

(1) If the baseline determination does not account for the fact turnarounds may

not have occurred during the baseline period, then EPA should include an

appropriate adjustment as part of the compliance determination process.

Letters:
Response to Comments

December 20, 2000

Page 99

Placid Refining Company, LLC (IV-D-2) p. 3

(2) Rule should have provision to account for aberrations in production levels and

benzene concentrations experienced in 1998-1999.

Letters:

Silver Eagle Refining, Inc. (IV-D-18) p. 2

Response 6.11.6(A)(1) and (A)(2): We are including a in the form of a baseline adjustment

provision for those refiners that can demonstrate how circumstances during 1998-2000

materially affected the baseline toxics value determination.

(B) EPA should establish a reasonable minimum for the number of batches

required to establish a baseline.

(1) If a refiner produced fewer batches during the baseline period than this

minimum, then the industry-average benzene levels would apply. This

exception would address, for example, non-CA RFG or CG produced by CA

refineries because those fuel types represent such a small portion of the

refineries' total production.

Letters:

Chevron (IV-D-34) p. 2

Tosco (IV-D-41) p. 4

Response to 6.11.6(B)(1): The regulations for this rule require that a refinery must have 12

consecutive months of data. Refineries with less than 12 months of data must comply with

the default baseline.

6.12: Testing, Reporting and Recordkeeping, and Compliance/Enforcement

Issues

(A) Proposed testing requirements are excessive.

(1) Since the proposed benzene content limit for CG is not a per gallon limit,

but rather an annual average, there is no need to impose a requirement

that the testing for benzene content be completed prior to batch

shipment. Furthermore, if EPA removes the testing prior to batch

shipment requirement of section 80.730(a)(1), the in-line blending

exemption requirement would not be needed.

Letters:

American Petroleum Institute (IV-D-21) p. 10

ExxonMobil (IV-D-16) p. 9

Koch Petroleum Group (IV-D-36) p. 4

National Petrochemical and Refiners Association (IV-D-33) p. 16

Phillips Petroleum Company (IV-D-20) p. A-4, A-5
Response to Comments

December 20, 2000

Page 100

Response to 6.12(A)(1): EPA agrees with the commenter’s recommendations on this issue. 

Since there is no per gallon standard for benzene or toxics emissions for conventional

gasoline, there is no need to test such gasoline prior to shipping. Therefore, EPA is

eliminating that requirement from today’s final rule. 

(2) Sample compositing is a less exact method for determining compliance

than every-batch analysis. Commenter suggests EPA not encourage

such approaches.

Letters:

American Petroleum Institute (IV-D-21) p. 13

Phillips Petroleum Company (IV-D-20) p. A-4

Response to 6.12(A)(2): EPA agrees that sample compositing is a less exact method for

determining compliance and therefore, EPA proposed eliminating sample compositing for

conventional gasoline in its 1997 proposal (62 FR 37337, July 11, 1997). However, it was

not the purpose of this rulemaking to address that matter. When EPA finalizes its 1997

NPRM, the issue of sample compositing for conventional gasoline will be addressed more

fully and today’s rule will be made consistent with that final rulemaking at that time with

regard to this issue.

(B) The dissimilar treatment of blending of downstream components into gasoline

raises questions as to the compliance approach intended by the Agency.

(1) EPA has explicitly excluded blenders of oxygenate and butane, but

failed to exclude the blending of other components, such as pentanes,

toluene and alkylate. EPA should maintain consistency in the treatment

of blendstocks in this rule with the treatment provided in other gasoline

antidumping and Tier 2 sulfur requirements.

Letters:

Phillips Petroleum Company (IV-D-20) p. A-4

Response to 6.12(B)(1): The commenter is only partially correct in its assessment of this

matter. All non-oxygenate blendstocks, including benzene, as well as those listed, are

included for compliance purposes in both the anti-dumping and Tier 2 requirements since

those blendstocks can adversely impact compliance with the applicable standards. However,

oxygenates and butane were explicitly excluded from the NPRM and today’s final rule

because they would not adversely impact annual average benzene or toxics emissions levels

which is not the case for the other blendstocks listed by the commenter.

 
Response to Comments

December 20, 2000

Page 101

(C) EPA should provide provisions to allow for effects of downstream oxygenate

blending to be adequately accounted for in determining benzene content.

(1) One commenter explained that as refiners switch from MTBE to ethanol,

oxygenate blending will shift from the refinery to the terminal. For RFG,

certain lab sample procedures apply, but for CG EPA needs to develop

appropriate procedures. The commenter added that EPA needs to

insure that this occurs without burdensome record keeping or

segregation requirements.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 9

Tosco (IV-D-41) p. 3-4

Response to 6.12(C)(1): At this time, there is no regulatory requirement that refiners shift

from the use of MTBE to ethanol. However, when, and if that occurs, the provisions

contained at 40 CFR §§ 80.69(a) and 80.101(d)(3) provide appropriate methods for refiners

to adequately account for the properties of gasoline at the refinery where oxygenates are

added downstream of the refinery. EPA does not believe that this creates any additional

burdensome record keeping or segregation requirements and is consistent with current

provisions contained in the RFG and anti-dumping programs.

(D) Opposes any new refinery reports as a result of this rulemaking.

(1) Any further reporting/attestation requirements should be added to

existing RFG and CG forms and reports.

Letters:

Tosco (IV-D-41) p. 4

Response to 6.12(D)(1): It was not EPA’s intention to create any additional reporting

requirements beyond those currently required for RFG and anti-dumping purposes. The

existing reports will be streamlined and/or modified as necessary to ensure their clarity and

the elimination of any incremental reporting burdens. 

(E) Because there are no downstream standards, enforcement should track

Subpart E, a similar annual averaging program that is refinery-based. Another

commenter stated that there is no need for anyone except the producer or

importer to retain records given the lack of downstream standards.

(1) Commenter provided no further supporting information or detailed

analysis.

Letters:

Koch Petroleum Group (IV-D-36) p. 4
Response to Comments

December 20, 2000

Page 102

National Petrochemical and Refiners Association (IV-D-33) p. 16

Response to 6.12(E)(1): The commenter suggests that since this is a refinery/importerbased program there is no need for downstream parties to retain records. EPA agrees and

therefore, has eliminated the requirements for records to be retained by any parties other

than refiners and importers in today’s final rule. 

(F) EPA should not adopt the proposed sampling compliance certification.

(1) A signed certification is already required under 80.770(c)(1), and

therefore 80.735(c) is redundant. If EPA decides to keep 80.735(c),

then it should be moved to 80.770 so that all reporting requirements are

in one location.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 16

(2) EPA should remove paragraph 80.730(c) that requires the

owner/operator to include in a compliance report a special certification

statement related to sampling compliance. Existing liabilities and noncompliance provisions provide EPA with adequate certification and

enforcement utility.

Letters:

Phillips Petroleum Company (IV-D-20) p. A-5

Response to 6.12(F)(1) and (2): The commenter suggest that the sampling compliance

certification under 80.735(c) is redundant and unnecessary in light of other regulatory

requirements and liabilities. EPA agrees and has eliminated that provision from the final

rule. 

(G) The rule should not require retention of sample portions for the most recent 20

samples collected because a refiner that produces one batch of gasoline per

year would be required to retain a sample portion for 20 years.

(1) Commenter provided no further supporting information or detailed

analysis.

Letters:

Koch Petroleum Group (IV-D-36) p. 4

Response to 6.12(G)(1): The commenter suggests that the requirement to retain portions of

the most recent 20 samples could result in samples being retained for an extraordinarily long

period of time if the refinery produces only one batch per year. EPA agrees and thus has
Response to Comments

December 20, 2000

Page 103

revised this provision to require sample retention for no more than 90 days in any case. This

same change is being made to the Tier 2 rule as well.

(H) EPA does not have the authority to set the parent corporation liability standard

found in section 80.795(a)(3) of the proposed rule.

(1) Commenter provides no further supporting information or detailed

analysis.

Letters:

Koch Petroleum Group (IV-D-36) p. 4

Response to 6.12(H)(1): The Clean Air Act, in §§ 211 and 301, provides very broad

authority for the Administrator to create necessary fuels regulations and appropriate means

to enforce them. Pursuant to this authority, the Agency has created presumptive liability

schemes in our fuels programs, which have been consistently upheld by the courts. Parent

corporation liability is derived from our presumptive liability scheme. It is also consistent with

our interpretation of the RFG regulations, as stated in the RFG and CG Questions and

Answer Document.

(I) Section 80.785(b) is unnecessary because it is not possible for a person to

"cause another person to commit" an averaging violation. Another commenter

argued that this provision and similar provisions in sections 80.795(a)(2) and

(b)(2) should be removed because they are not applicable to RFG or antidumping subpart in EPA's rules and will only create confusion amongst these

similar programs.

(1) Commenter provides no further supporting information or detailed

analysis.

Letters:

Koch Petroleum Group (IV-D-36) p. 4

National Petrochemical and Refiners Association (IV-D-33) p. 16

Response to 6.12(I)(1): The commenter suggests that it is not possible for another party to

cause a party to commit an averaging violation and therefore, prohibitions and liability for

such actions are not appropriate in this rule. EPA disagrees. While it is unlikely that this will

occur, it is possible for two parties to act in collusion whereby one party improperly shifts or

sells gasoline to another party for incorporation in the second party's compliance calculations

which leads to an averaging violation when the compliance calculations are corrected. 

Similarly, it is possible that a downstream party, for monetary reasons, might induce a refiner

to produce noncomplying fuel, which might be less expensive to produce, and to sell that less

expensive fuel to the downstream party. In these cases, EPA believes the collusive parties

would have caused the refiner to commit an averaging violation. Additionally, these same

requirements are contained in the Tier 2 final rule for similar standards and EPA is currently

standardizing its rules where appropriate. 
Response to Comments

December 20, 2000

Page 104

The Agency disagrees with the commenters’ additional argument that inclusion of the

causation liability in the toxics rule would cause confusion between programs because such

causation liability does not exist in the RFG and CG programs. Causation liability has been

an integral part of EPA’s typical presumptive liability schemes, including those found in the

RFG and CG programs. EPA’s effective, multi-party presumptive liability approach

established under our fuels programs has consistently been based on the fact that any of the

parties in the distribution system could have caused the violation. Further, the Tier 2 gasoline

sulfur rule specifically imposes causation liability similar to that found under the toxics rule.

(See the preamble to the final Tier 2 gasoline sulfur rule, 65 FR 6813.) Because of this prior

history of causation liability within the presumptive liability schemes of numerous fuels

programs, the Agency does not believe that specifically including causation liability in the

toxics rule will cause confusion. 

(J) Baseline information may qualify as CBI for disclosure purposes.

(1) One commenter notes that EPA-approved benzene baseline and batch

data for each refinery should be considered confidential business

information.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 15-16

Response to 6.12(J)(1): We agree that certain information in a refiner’s baseline

submission may be considered Confidential Business Information (CBI). Such information

would include batch and total gasoline volume information, batch data, and seasonal fuel

parameter and emissions information. However, it is possible that the annual average toxics

baseline emissions values determined for this rule may not be considered CBI. The annual

average baseline emissions under the anti-dumping program were not considered CBI. 

Nonetheless, a refiner should label all information in the baseline submission it deems to be

CBI as such.

6.13: Economic Impacts

6.13.1: Costs 

(A) The proposed rule is not cost effective. (See related comments under Issue

6.6.)

(1) No cost effectiveness analysis has been conducted, and no benefit-cost

analysis has been completed. EPA has not established the need for, nor any

benefits from, these more stringent standards. The proposed rule fails to take

into account the impact of other regulatory initiatives relating to gasoline

composition and other factors that could result in costs to refiners, and therefore

EPA cannot proceed without analyzing the costs and benefits of the proposed

rule. One commenter stated that because the costs will exceed $100 million,

EPA is required to do an analysis under UMRA. Some of these commenters

also argue that EPA must publish another notice for comment after completing

this type of analysis.
Response to Comments

December 20, 2000

Page 105

Letters:

American Petroleum Institute (IV-D-21) p. 1-2

ExxonMobil (IV-D-16) p. 2

Marathon Ashland Petroleum, LLC (IV-D-15) p. 1-2, 4-5

Murphy Oil Corporation (IV-D-17) p. 3-4

National Petrochemical and Refiners Association (IV-D-33) p. 2

Phillips Petroleum Company (IV-D-20) p. 2

Response to 6.13.1(A)(1): As described in the Technical Support Document, the

environmental benefit associated with our anti-backsliding program is that it

ensures the current overcompliance exhibited in both RFG and CG will be

preserved. This overcompliance will amount to approximately 40,000 tons of

toxics emissions in year 2007. Absent this rulemaking, there is a possibility that

some or all of this overcompliance could fail to manifest in 2007.

In the Notice of Proposed Rulemaking, we proposed a benzene content requirement 

in order to capture the significant amount of overcompliance above and beyond

the requirements of the federal reformulated gasoline and anti-dumping

programs. Our preliminary cost analysis predicted that the proposal would

impose only negligible costs. The Agency asked for comment on two other

forms of the today’s rule: benzene emissions performance and toxics emissions

performance. 

In response to these comments, and based on more detailed refinery modeling

performed for this rule, we are finalizing a toxics performance requirement

instead of a benzene content requirement. The Agency’s general rationale is

twofold: a toxics performance requirement captures a larger amount of the

overcompliance with the existing standards and imposes less costs on the

refining industry than the proposed benzene content requirement. 

 Even though this program does not require new capital investments or changes in

refinery operations, and thus should pose no additional burden on refiners, we

have included a number of compliance flexibilities, such as deficit and credit

carryforward provisions, and a compliance margin, to offset unexpected or

unusual variances in the gasoline quality of a refinery (or importer). For a more

detailed discussion of the refinery modeling for this rule, please see Chapter

7.C. of the Technical Support Document.

The results of our refinery modeling for a benzene anti-backsliding program showed

negligible costs to industry. Additional analysis for RFG and CG under a toxics

performance requirement showed that today’s action will impose only negligible

costs. Because today’s rule will result in only negligible costs far less than $100

million in any one year to State, local, and tribal governments, in the aggregate

or to the private sector, the Agency is not required to do an analysis under

UMRA. We believe that the analysis of our costs on today’s program is

sufficient and we are not required to publish a supplemental notice for comment

on the issue of costs from this program.
Response to Comments

December 20, 2000

Page 106

(2) EPA's claim to the contrary notwithstanding, EPA has been given information

demonstrating that the proposal will have significant costs. MAP presented

EPA with benzene reduction costs in January 2000. EPA participated in the

National Petroleum Council gasoline and diesel producibility study and is

therefore familiar with the costs to refiners and the loss of flexibility associated

with maintaining RFG toxics performance under an MTBE ban or reduction.

Letters:

Marathon Ashland Petroleum, LLC (IV-D-15) p. 1-2

Response to 6.13.1(A)(2): When EPA met with MAP in January 2000, the only confidential

business information on costs supplied to EPA at that time was on various

benzene cap programs, not a toxics anti-backsliding program. For more

information on costs due to a toxics anti-backsliding program please see the

TSD, Chapter 7.C and the response to 6.13(A)(1). For a response to comments

on the costs to refiners and the alleged loss of flexibility associated with

maintaining RFG toxics performance under an MTBE ban or reductions, please

see response 6.6(D)(1).

(3) In the 1994 RFG rule, EPA stated that the main control strategies for toxics,

benzene and aromatics are very expensive, in excess of $100 million/CI. EPA

could have imposed more stringent air toxics requirements on RFG, but

expressly declined to do so. Rather, EPA found that the costs of doing so

would far exceed the costs incurred in other programs for the same benefit.

Letters:

American Petroleum Institute (IV-D-21) p. 3

Chevron (IV-D-34) p. 1

Marathon Ashland Petroleum, LLC (IV-D-15) p. 4

Murphy Oil Corporation (IV-D-17) p. 4-5

Phillips Petroleum Company (IV-D-20) p. 2

Response to 6.13.1(A)(3): The RFG program established a toxics emission performance

standard for RFG, and an anti-backsliding toxics standard for conventional

gasoline based on 1990 baseline toxics levels for each refinery. On average,

refiners have overcomplied with the toxics emisisons performance standards for

both RFG and CG. Overcompliance of RFG standards resulted in substantial

toxics reductions beyond what was required by law. We have estimated that the

reduction in the total toxics inventories due to overcompliance was

approximately 70 thousand tons in 1996 and will be approximately 40 thousand

tons in 2007 (see TSD). The cost estimates in the 1994 RFG rule have

obviously proven to be excessive given the fact that refiners have voluntarily

reduced their benzene levels below the RFG requirements. The refinery

modeling that was completed for the toxics performance requirement shows that

we can capture current overcompliance at negligible costs. For a more detailed
Response to Comments

December 20, 2000

Page 107

discussion of the refinery modeling for this rule, please see Chapter 7.C. of the

Technical Support Document. 

(B) The proposed rule places an economic penalty on those refiners that

overcomplied during the baseline period. (See related comments under Issue

6.6.)

(1) EPA states that no refinery capital expenditures or operational changes will be

needed to comply with this proposal because it requires refineries to continue

what they did in 1998-99. However, there are market factors which may require

refiners to change their operations to comply with the proposed regulation. For

example, gasoline benzene levels are dependent on chemical market

economics for benzene production and recovery. A depressed chemicals

market will increase refinery costs to remove benzene. Such factors will

increase compliance costs for refiners with large RFG production volumes, very

low benzene baselines, and little operational flexibility to further reduce benzene

levels. Initial estimates suggest that an incremental baseline reduction of only

0.2% for these refineries can be in the range of 3-4 cents/gallon.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 3

Sunoco, Inc. (IV-D-23) p. 1-2

Response to 6.13.1(B)(1): Since we have switched to a toxics performance requirement for

this final rule, refiners will have more flexibility to address fluctuations in the

benzene content of fuel than they would under the proposed benzene content

standard. With regard to refineries that achieved low emissions levels due to

benzene extraction, we do not believe there is any basis for expecting the

benzene market to change in such a way that warrants setting a minimum toxics

performance level. In fact, projections of the benzene market suggest

continued growth (see TSD, Chapter 7.A.3). 

We do realize that even for a toxics anti-backsliding program, unusual situations may

happen that can significantly affect refinery operations, and which could cause

the refinery to be out of compliance with its requirement. To this end, we

proposed and are finalizing a one-year deficit carryforward provision. This will

allow a refinery to exceed its anti-backsliding toxics requirement for one year. 

In the next year, it must make up the deficit as well as be in compliance for that

year. Additionally, though not proposed, we are also including a one-year credit

carryforward provision. Under this provision, a refinery producing gasoline that

is cleaner than required by its toxics anti-backsliding requirement may bank the

credits from overcompliance to cover any deficit in the following year. 

Although we did not propose to include a compliance margin on the fuel benzene

content requirement in the NPRM, additional information gleaned from refinery

modeling and comments has led us to include a compliance margin on the TPS

being finalized today. Though refinery modeling shows that post-2004 RFG
Response to Comments

December 20, 2000

Page 108

total toxics and CG exhaust toxics emissions in PADDs I and III will, on average,

be lower than during the baseline period, the difference is not large enough to

ensure that refiners won’t have to go beyond what our anti-backsliding

requirements strictly call for. Also at this time, we do not know whether the

lower toxics emissions predicted by refinery modeling is true of gasoline in other

PADDs. Thus we have provided refiners with compliance flexibility in several

forms.

(2) Some refiners remove most of the benzene from their reformate streams. The

only way to further lower benzene content is to remove it from the catalytic

cracker gasoline stream, but the science of doing so is not well understood. 

The economic penalty for this control will likely be extreme and still have only a

minimal effect on actual benzene levels.

Letters:

Citgo Corporation (IV-D-5) p. 2

Phillips Petroleum Company (IV-D-20) p. 3

Response to 6.13.1(B)(2): Since we have switched to a toxics performance requirement for

this final rule, refiners will have more flexibility to address fluctuations in the

benzene content of fuel than they would under the proposed benzene content

standard. 

Our analysis of refinery reports submitted for the years 1997 through 1999 showed

little difference in fuel benzene levels between the years, or for either type of

gasoline, RFG or conventional. Since refiners would have already been

planning ahead for the implementation of the Phase II RFG program in 1999,

one would have expected a difference in either RFG or CG in 1999 compared to

1997 or 1998 if Phase II RFG were to have an impact on benzene levels. 

Therefore during the time that refiners will have to comply only with the Phase II

RFG, we do not believe that benzene levels will increase significantly. 

In addition, our refinery modeling comparing the year 1999 as a base case year to the

year 2005 as the reference case year (accounting for expected changes in fuel

properties due to Phase II RFG, Tier 2 low-sulfur gasoline and 15 ppm lowsulfur diesel fuel (based on the proposed HD07 rule)) showed that for CG, the

toxics emissions are likely to remain at or below 1999 levels and that for RFG,

refiners are likely to be able to meet or exceed the new toxics baseline

requirements. Therefore, on average we do not anticipate that benzene levels

will increase significantly for refiners during the implementation of these future

fuels programs. Based on the refinery modeling and analysis presented in

Chapter 7.C of the TSD, we believe that the new toxics performance

requirement finalized in today’s action will impose negligible costs on the

refining industry for both RFG and CG.

Because benzene levels are not expected to increase significantly during the early

part of the Phase II RFG program and because the toxics emissions

performance of both RFG and CG is expected to meet or exceed 1999 levels
Response to Comments

December 20, 2000

Page 109

after implementation of Tier 2 and low-sulfur diesel controls, we do not believe

that it will be necessary for refiners to remove benzene from catalytic cracker

gasoline streams in order to meet the requirements of today’s toxics antibacksliding program.

(C) Reducing benzene content reduces the quantity of premium gasoline a refiner

can economically produce.

(1) Benzene is a major component in high octane gasoline. Reducing benzene

results in reduced octane gasoline, and cuts overall premium gasoline

production. Another commenter similarly noted that by limiting refiner flexibility

to increase gasoline production, EPA will jeopardize gasoline supplies as

gasoline demand is projected by DOE to increase annually by 1.9%.

Letters:

American Petroleum Institute (IV-D-21) p. 2, 5

Gary Williams Energy Corporation (IV-D-3) p. 2

Response to 6.13.1(C)(1): Contrary to the commenters claims that benzene is a major

component in high octane gasoline, the 1996 API/NPRA survey seems to

indicate otherwise. According to the 1996 API/NPRA survey, Table 1 indicates

that for the total U.S., excluding California, CG premium has 16 percent less

benzene than CG regular, VOC Region 1 RFG premium has 11 percent less

benzene than VOC Region 1 RFG regular, and VOC Region 2 RFG premium

has 1 percent less benzene than VOC Region 2 RFG regular.

Nevertheless, because we have decided not to control incremental volumes in

today’s final rule, refinery concerns regarding increased gasoline production due

to increased demand in future years is no longer a concern.

(D) Small refiners will have difficulty complying with this rule given the need to

comply with the MTBE and gasoline sulfur rules at the same time.

(1) Small refiners would have to purchase additional equipment to ensure

compliance with all three sets of standards. It is not clear how they would be

able to obtain financing for the required equipment when all small refiners would

have to meet these standards in the same timeframe.

Letters:

U.S. Small Business Administration (IV-D-26) p. 3

Response to 6.13.1(D)(1): The results of our refinery modeling for the toxics performance

anti-backsliding requirement indicate that the costs of this program will be

negligible. We do not believe that additional significant equipment will be

required to comply with today’s toxics performance anti-backsliding requirement

for small refiners. Therefore no extra lead time is required to comply with a

today’s final rule. Thus, beginning with the 2002 calendar year, a refinery’s or
Response to Comments

December 20, 2000

Page 110

importer’s annual average toxics emissions performance, determined separately

for RFG and CG, cannot exceed its baseline toxics emissions performance,

determined over the three years 1998-2000. The first report associated with

today’s rule will be due February 28, 2003, the same date as the reformulated

gasoline and anti-dumping reports are due for calendar year 2002.

(2) Small refiners may be forced to rely on new or unproven performance additives,

or further change refinery production configurations.

Letters:

Countrymark Cooperative, Inc. (IV-D-35) p. 2

Response to 6.13.1(D)(2): We do not agree that this rule, in connection with future controls,

will force small refiners to change their formulations or production

configurations. Our refinery modeling for a toxics performance requirement

indicates that there will no significant impact on small or large refiners from the

Phase II RFG program, Tier 2 low-sulfur gasoline program, and/or the 15 ppm

low-sulfur diesel rule (based on the proposed HD07rule).

We did not conduct a detailed analysis of potential MTBE controls because we are

still currently working on our MTBE proposal and it would be premature to

consider the possible impacts from this effort. Any toxics emissions impacts

associated with a phase-down or phase-out MTBE under the Toxic Substances

Control Act (TSCA) will be considered in that rulemaking. 

6.13.2: Benefits

(A) EPA has failed to demonstrate any environmental benefit for moving forward

with this regulation.

(1) Commenter fails to understand the logic or the need for this regulation. 

Moreover, EPA has not demonstrated that refiners will fail to continue to overcomply even without this rule.

Letters:

Marathon Ashland Petroleum, LLC (IV-D-14) p. 1, 4

Response to 6.13.2(A)(1): The statute requires that we adopt controls for at least benzene

and formaldehyde that represent greatest degree of emission reductions

achievable. We believe that the anti-backsliding requirement being

promulgated today is achievable because refiners are already meeting these

levels. A failure to adopt at least this level of toxics control would therefore be

inconsistent with the statutory mandate.

We are not under an obligation to prove that refiners will fail to overcomply in the future with

the current RFG and anti-dumping toxics standards. In establishing an anti-
Response to Comments

December 20, 2000

Page 111

backsliding program, we are only protecting the environment against the

possibility that the overcompliance exhibited in 1998 - 2000 will degenerate in

the future through increases in fuel benzene content or changes in other fuel

properties. If in reality no changes to fuel properties occur that collectively

would place upward pressure on toxic emissions, our toxic performance

standard will impose no constraints on refiners. 

As described in the Technical Support Document, the environmental benefit associated with

this rule is that it ensures that the current overcompliance exhibited in both RFG

and CG will be preserved. We estimate that this preserved overcompliance will

amount to approximately 40,000 tons of toxics emissions in year 2007. Absent

this rulemaking, there is a possibility that some or all of this overcompliance

could fail to manifest in 2007.

(2) EPA acknowledges in the NPRM that the proposal is not expected to reduce

emissions beyond what is currently being achieved. One must conclude from

this assessment that public health is already being adequately protected. In

fact, EPA's "Latest Findings on National Air Quality: 1999 Status and Trends"

states that benzene levels in 84 urban areas dropped 39% from 1993 to 1998,

and EPA anticipates a 75% drop in key toxics from highway vehicles by 2020.

Letters:

American Petroleum Institute (IV-D-21) p. 1, 4

American Petroleum Institute (IV-F-1) p. 33

ExxonMobil (IV-D-16) p. 1

Murphy Oil Corporation (IV-D-17) p. 4

Phillips Petroleum Company (IV-D-20) p. 2

Response to 6.13.2(A)(2): It is true that ambient benzene concentrations have dropped in

recent years. Future reductions in total HC emissions due to the rollout of new

vehicle, engine, and fuel standards are predicted to result in continuing

reductions in toxics emissions. For these reasons and others, we have

determined that the most appropriate toxics control program to implement at this

time is one that preserves the reductions resulting from overcompliance with the

RFG and anti-dumping standards. 

However, despite the expectation that programs currently in place will reduce inhalation

exposure to gaseous air toxics from highway mobile sources by about 50% in

2007 and 60% in 2020, relative to 1996 levels, mobile sources will continue to

be major contributors to exposure and risk from outdoor sources of air toxics. 

Unfortunately, there are many data gaps which prevent us from fully

characterizing risks. As we address these data gaps over the next few years we

will evaluate what additional controls may be needed to adequately protect

public health. As a result we have decided to include a commitment in this

rulemaking to conduct further investigation into these issues in a Technical

Analysis Plan, and to promulgate additional toxic emission standards by July,

2004 if we deem them appropriate.
Response to Comments

December 20, 2000

Page 112

(3) According to EPA's "Summary of Peer Reviews of Motor Vehicle-Related Air

Toxics Study", one independent scientist stated that "there appears to be no

cause for a public health concern for cancer from exposure to mobile vehicle

exhaust, and it would seem that the agency could use its resources more

productively on matters of higher concern."

Letters:

American Petroleum Institute (IV-D-21) p. 1

American Petroleum Institute (IV-F-1) p. 34

Murphy Oil Corporation (IV-D-17) p. 5

Response to 6.13.2(A)(3): We do not believe that the existing data on toxics emission rates

from vehicles and engines, correlations between fuel properties and toxics

emissions, ambient concentrations of toxic pollutants and exposure to those

pollutants is sufficiently robust for us to conclude that no public health concern

exists. As a result we have established a Technical Analysis Plan to further

investigate these issues. In the meantime we are promulgating an antibacksliding program that is designed to preserve the emission benefits

associated with overcompliance with the RFG and anti-dumping programs, and

that represents the greatest degree of emissions reductions achievable in the

short term.

6.14: Other Fuel Issues

6.14.1: Anti-dumping Program

(A) EPA should repeal the antidumping requirements for CG after the proposed

benzene standard and Tier 2 sulfur controls go into effect.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Marathon Ashland Petroleum, LLC (IV-D-15) p. 8

Sunoco, Inc. (IV-D-23) p. 3

(2) With the MSAT standards and the Tier 2 rule, the anti-dumping regulations will

be unnecessary. Compliance with the Tier 2 and benzene standards will meet

or exceed the NOx and exhaust toxics specifications required by the

antidumping regulations, allowing refiners to save on analytical testing and

recordkeeping.

Letters:

American Petroleum Institute (IV-D-21) p. 9

Citgo Corporation (IV-D-5) p. 4

ExxonMobil (IV-D-16) p. 9-10

Phillips Petroleum Company (IV-D-20) p. 5
Response to Comments

December 20, 2000

Page 113

Placid Refining Company, LLC (IV-D-2) p. 3

(3) If the new anti-backsliding gasoline benzene regulations are effective in 2002,

then the anti-dumping exhaust toxics regulations should be repealed effective

January 1, 2002. However, the reports for 2001 anti-dumping compliance

should still be submitted to EPA in 2002.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 12

Response to 6.14.1(A)(1), (A)(2), and (A)(3): We are not repealing the anti-dumping

program. The anti-dumping program is required by the Clean Air Act and we

cannot ensure that today’s requirements and the Tier 2 gasoline sulfur

requirements will exactly duplicate the anti-dumping program. For example, the

gasoline sulfur standards do not guarantee that all conventional gasoline will

meet the individual NOx performance standards because some anti-dumping

individual baselines have even lower average sulfur levels than the gasoline

sulfur program will require. Additionally, the flexibilities provided in today’s rule,

such as deficit and credit carryforward, could cause the anti-backsliding toxics

emissions performance for certain refineries to exceed their anti-dumping toxics

performance requirement in a given year. Finally, because the anti-dumping

statutory baseline becomes a part of a refinery’s anti-dumping compliance

determinations when the refinery’s annual production exceeds its 1990 baseline

volume, depending on the refinery’s baseline, it’s standard for that year could be

more stringent than the anti-backsliding requirement. 

(B) Opposes NPRA suggestion to eliminate the CG antidumping program because

it is vitally important that conventional gasoline be protected from increased

benzene levels that could result from the proposed program.

(1) Instead, CG benzene limits should be set at 1998-99 baseline levels for each

refinery.

Letters:

Bluewater Network (IV-D-29) p. 2

Response to 6.14.1(B)(1): See response to 6.14.1(A)

(C) EPA should consider eliminating the anti-dumping requirements only if there

are no negative gasoline quality, vehicle emissions or air quality impacts.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Tosco (IV-D-41) p. 4
Response to Comments

December 20, 2000

Page 114

14 "Petition To Regulate Gasoline Distillation Properties," submitted by DaimlerChrysler Corporation, Ford

Motor Company, General Motors Corporation, and the Association of International Automobile Manufactuers. 

January 27, 1999. EPA Air Docket A-97-10, document number II-G-286.

Response to 6.14.1(C)(1): See response to 6.14.1(A)

6.14.2: Other Fuel Specifications 

(A) EPA should address other fuel components in addition to benzene.

(1) First, EPA should cap the Distillation Index at 1200 which would further reduce

benzene emissions during cold start. EPA should also cap levels of polynuclear

aromatic compounds in diesel fuel at 2% by volume to reduce tailpipe benzene

emissions. Finally, EPA should adopt the rest of the recommendations in the

World Wide Fuels Charter.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 5-6

Alliance of Automobile Manufacturers (IV-F-1) p. 63

Response to 6.14.2(A)(1): Controls on the Distillation Index (DI) of gasoline may result in

reductions in HC emissions, which in turn would reduce toxics emissions. 

However, toxics are a very small portion of total HC emissions, so that

controlling DI for the purposes of reducing toxics emissions would be highly

cost-ineffective. We received a petition in January 1999 requesting that we

control DI for the purposes of reducing tailpipe HC emissions14. We intend to

conduct a more thorough review of that petition early in 2001 and will at that

time determine if DI controls are warranted.

As described in Chapter VII of the the Draft Technical Support Document, benzene

emissions from gasoline-powered vehicles far exceeds that from diesel

vehicles; in 1997, highway emissions of benzene from gasoline-powered

vehicles were estimated to be over 50 times higher than diesel-based emissions

of benzene. Insofar as benzene represents a toxic pollutant meriting control,

therefore, it is much more efficient to target benzene emissions from gasolinepowered vehicles. Regardless, we do not currently have any correlations

between aromatic compounds in diesel fuel and the associated benzene

emissions, and so are not in a position to place controls on polynuclear aromatic

compounds in diesel fuel.

The World Wide Fuels Charter represents a selection of fuel specifications which

manufacturers have decided would maximize the efficient operation of their

vehicles and engines. The EPA has not received a formal petition requesting

that all elements of the World Wide Fuels Charter be adopted into regulation. 

Certainly we are aware of no analyses indicating how adoption of all elements

of the World Wide Fuels Charter would affect emissions of toxics pollutants. 

However, we continue to evaluate the benefits and cost-effectiveness of various
Response to Comments

December 20, 2000

Page 115

fuel control options, and future actions may include new or amended fuel

controls as we deem them appropriate.

(B) EPA fails to account for the roles of toluene, xylene and higher aromatics in the

formation of benzene.

(1) These compounds are precursors to benzene, and can be readily formed by the

catalytic converter. These compounds also are usually deliberately synthesized

in the fuel to increase fuel octane.

Letters:

NESCAUM (IV-D-9) p. 8-9

Response to 6.14.2(B)(1): We agree that benzene analogs such as toluene and xylene will

contribute to the formation of benzene emissions. However, we do not currently

have any means for correlating specific changes in the fuel concentration of

these compounds with benzene emissions. In addition, the available

information on the concentration of these benzene analogs in gasoline is quite

limited. The Complex Model does permit us to estimate the impacts of changes

in total aromatics content on benzene emissions, though as discussed in our

response to issue 6.5.3(B)(1), the impact of aromatic compounds on benzene

emissions is far less than the impact of fuel benzene content on benzene

emissions. It was for this reason that we proposed controls on fuel benzene

content in our NPRM.

Still, we recognize that properties other than fuel benzene content can affect emissions of

toxics compounds. This is one reason that we have decided to finalize a toxic

performance requirement instead of the benzene content standard we

proposed. As a result, it will not be necessary to account specifically for the role

of toluene and xylene in the formation of benzene emissions, but instead such

impacts will be taken into account implicitly when refiners comply with their 1998

- 2000 toxics emissions baselines.

(C) EPA should expand the rule to include all aromatic compounds in gasoline.

(1) Lowering aromatic levels in gasoline will significantly reduce these pollutants, as

well as directly reduce CO2 emissions. This is especially important in the

context of a likely national phase-out of MTBE (which the commenter supports). 

Without MTBE, refiners are likely to consider increasing aromatic content to

replace octane loss. EPA should adopt an anti-backsliding requirement for all

aromatics that mirrors the approach taken for benzene. Another commenter

raised general concerns about the potential for increased toxics from other

sources with a phase-out of MTBE.

Letters:

Bluewater Network (IV-D-29) p. 1-2
Response to Comments

December 20, 2000

Page 116

Michigan Environmental Council (IV-F-1) p. 68

Response to 6.14.2(C)(1): The EPA is committed to ensuring that any change in the

regulatory requirements regarding MTBE are promulgated in such a way that

the current and predicted future emission benefits of overcompliance with the

RFG and anti-dumping standards are preserved. The anti-backsliding program

that we are finalizing today will apply even if MTBE is phased-out. Although our

anti-backsliding program does not place controls on the benzene or aromatic

content of the fuel specifically, it does ensure that toxics emissions from both

RFG and CG can be no higher than they were in 1998 - 2000. As a result we

do not believe it is necessary to place individual controls on both the benzene

and aromatic contents of gasoline. Note that the forthcoming rulemaking on the

MTBE phaseout will address the issue of toxics emissions in the context of

octane corrections that may be necessary if MTBE is phased-out.

(D) EPA needs to evaluate fuel control options to regulate other toxic compounds

that contribute to unacceptable health risks, such as 1, 3-butadiene,

formaldehyde, and aromatics.

(1) Commenter provides no detailed analysis supporting this point.

Letters:

NESCAUM (IV-D-9) p. 7

Response to 6.14.2(D)(1): As described in the preamble, we have determined that an antibacksliding program which preserves the toxics overcompliance benefits

exhibited in 1998 - 2000 is most appropriate for this rulemaking. The most

comprehensive approach to preserving those overcompliance benefits is to

ensure that toxics emissions, as measured by the Complex Model, are no

higher in the future than they were in 1998 - 2000. Using this approach we

capture not only benzene emissions, but also 1,3-butadiene, formaldehyde,

acetaldehyde, and polycyclic organic matter. Currently we do not have any

precise means for evaluating the impact of fuel properties on emissions of

aromatic compounds, so we cannot place controls on aromatic compounds

specifically at this time. However, we believe that our anti-backsliding program,

with its focus on toxics performance, places controls on the primary toxic

compounds that are emitted from gasoline-powered vehicles and engines.

(E) If not well coordinated, conflicting fuel requirements could reduce refinery

flexibility without providing added environmental benefits.

(1) EPA should carefully coordinate this proposal with other rulemakings such as

MTBE, new renewable fuel requirements, and other toxics/aromatics limits on

RFG. The commenter noted that EPA specifically must coordinate the antibacksliding provision with other proposals that would add more stringent RFG

aromatics and toxics standards.
Response to Comments

December 20, 2000

Page 117

Letters:

Tosco (IV-D-19) p. 2

Response to 6.14.2(E)(1): We have evaluated the costs and benefits of our anti-backsliding

program by taking into account all promulgated programs. This approach is

consistent with the approach taken for past rulemakings; whenever a new

control program is proposed, it must be evaluated within the context of the other

controls programs that we know will be in effect at the same time. 

For potential future control programs which are not yet promulgated and thus have yet to be

clearly defined, such an evaluation is very imprecise and in fact can lead to

erroneous results if the final program differs substantially from the proposed

program. It is incumbant upon authors of control programs which have yet to be

finalized to calculate the costs and benefits of their program in the context of

those control programs that are already promulgated. As a result, we have not

evaluated the costs and benefits of our anti-backsliding program under the

assumption that MTBE will be phased-out, a renewable fuel requirement will be

implemented, or other toxics or aromatics limits will be placed on gasoline. All

of these potential programs are as yet unspecified and thus cannot form the

basis of a comparative analysis. On the contrary, when evaluating the impacts

of an MTBE phaseout, for example, EPA must do so assuming that the antibacksliding program for toxics is already in place, since the program in today's

final rulemaking will be promulgated before any MTBE phaseout program is

finalized. You should review the analyses in the forthcoming MTBE phaseout

rulemaking to determine how we have evaluated the coincident impacts of our

anti-backsliding program and the MTBE phaseout program on costs and

environmental benefits.

6.15: SBREFA and Small Refiner Flexibility Options

(A) EPA should initiate a SBREFA process.

(1) This rule is expected to impose significant costs on small refiners already

subject to Tier 2 gasoline requirements. Also, the "no-cost" analysis does not

factor in the anticipated MTBE phase-out or that other regulations may

disproportionately impact small refiners. [See related comments under Issues

6.6 and 6.13.1.]

Letters:

Gary Williams Energy Corporation (IV-D-3) p. 3

Placid Refining Company, LLC (IV-D-2) p. 1

Response to issue 6.15(A)(1): EPA disagrees with this comment. The Agency performed

refinery modeling for this rulemaking. Based on the results of the refinery

modeling, the Agency concluded that this rule is not expected to impose

significant costs on refiners, large or small, after Phase II RFG, Tier 2 low sulfur
Response to Comments

December 20, 2000

Page 118

gasoline and the heavy-duty vehicle low sulfur diesel fuel are taken into

account. MTBE phase out, or phase down, is too uncertain and unspecified at

this time. When and if a rule on MTBE is proposed, the new baseline

requirements established in this rule will be taken into consideration when

developing cost estimates for that rule.

(2) SBREFA requirements are applicable and must be engaged if small business

refiners are held to some future benzene standard established using an

inappropriate baseline time period during which EPA required oxygenate use,

which now appears likely to be followed by a period in which oxygenate use will

be prohibited or curtailed.

Letters:

Kern Oil & Refining, Inc. (IV-D-31) p. 4-5

Western Independent Refiners Association (IV-D-40) p. 3

Response to issue 6.15(A)(2): This rule will not impose a significant impact on a substantial

number of small entities (see response to 6.15(A)(1)). Therefore, the

SBREFA/RFA requirements for convening a panel and preparing a regulatory

flexibility analysis are not triggered by this rulemaking. 

(B) Small refiners should be exempt from the proposed regulation.

(1) The total volume of small refiners' gasoline is a very small percentage of the

total U.S. consumption. Any impact of this proposal on small refiners will be

disproportionately greater than on large refiners, and by EPA's own admission,

existing controls are reducing benzene emissions.

Letters:

Placid Refining Company, LLC (IV-D-2) p. 2

Response to issue 6.15(B)(1): EPA does not dispute the fact that small refineries do not

produce a large portion of total US domestic consumption. However, as

described in the preamble, we are implementing an anti-backsliding program for

toxics emissions that are expected to have only negligible costs. As a result we

are applying the program to all refiners.

(C) Supports an exemption from Phase I requirements for small refiners.

(1) Small refiners should be exempt from anti-backsliding standards until at least

2004 when EPA has completed further review. A one-step approach is

important so that small refiners can plan investment, engineering and

construction for a final standard. Phase-in approaches impose burdensome

and unnecessary equipment installation and expenditure. Also, because small

refiners contribute such a small fraction to the benzene problem or hot spots of

pollution, there is no need to include them in the first phase.

Letters:
Response to Comments

December 20, 2000

Page 119

Gary Williams Energy Corporation (IV-D-3) p. 3

Response to issue 6.15(C)(1): This anti-backsliding rule will not require refineries to invest

in new equipment. See our response to issue 6.13.1(D)(2).

(2) EPA should defer consideration of any anti-backsliding standards for small

refiners until 2003-04. A delay would allow EPA to study the impact of this rule

on the balance of the industry and to understand its interaction with the gasoline

sulfur rule and any MTBE phase-down.

Letters:

U.S. Small Business Administration (IV-D-26) p. 4

Response to issue 6.15(C)(2): EPA sees no reason to delay promulgation of these

regulations. Refinery modeling conducted for the rule shows that for PADDs I

and III, refineries are likely to incur only negligible costs. 

(D) EPA should provide for a two-year moratorium in the effective date for small

refiners.

(1) Commenter provided no further supporting information or detailed analysis.

Letters:

Countrymark Cooperative, Inc. (IV-D-35) p. 3

Response to issue 6.15(D)(1): Since our anti-backsliding program is expected to impose

only negligible costs on refiners and will require no capital investments, we do

not believe that small refiners need additional time to prepare for compliance. 

Therefore, we have imposed the same effective date on all refiners.

(E) Small refiners, and those refiners in Tier 2 geographic phase-in areas, should

be allowed to establish their baseline periods after they reach compliance with

the Tier 2 rule to account for potential baseline increases from Tier II

compliance efforts.

(1) This is especially important for small refiners that install Tier II gasoline

processing facilities prior to the 2008 deadline.

Letters:

Murphy Oil Corporation (IV-D-17) p. 2

Response to issue 6.15(D)(1): It is true that reductions in gasoline sulfur content tend

also to result in increases in fuel benzene content due to the octane corrections

that are often required in conjuction with desulfurization. However, according to

the modeling described in Chapter VII of the Technical Support Document, on

average toxics emissions are predicted to go down after the low sulfur standard
Response to Comments

December 20, 2000

Page 120

of 30 ppm is implemented. Since we are finalizing a toxics performance

requirements instead of a benzene content standard, we do not expect the Tier

2 sulfur standard to impose a burden on refiners in terms of complying with their

1998 - 2000 toxics performance levels. Therefore, we have made no provision

for any refiners to establish or re-establish their baselines after they reach

compliance with the 30 ppm sulfur standard.
Response to Comments

December 20, 2000

Page 121

ISSUE 7: TECHNICAL ANALYSIS PLAN

(A) Supports EPA's decision to continue mobile source air toxics research.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Association of International Automobile Manufacturers (IV-D-7) p. 1

(2) Commenter supports EPA's proposed review of in-use air toxic emissions and

its intention to consider additional measures in the future.

Letters:

Oregon Environmental Council (IV-D-9) p. 1

(3) EPA should form a close partnership with HEI as it progresses with the TAP in

order to provide an objective, independent resource to conduct the literature

reviews and research necessary to assist EPA in determining which pollutants

might be of public health concern.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 2

Alliance of Automobile Manufacturers (IV-F-1) p. 60-62

(4) The plan will provide the necessary research and analysis to help determine key

sources of individual toxics and risks associated with these toxics.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 2

Alliance of Automobile Manufacturers (IV-F-1) p. 60

(5) However, EPA should include appropriate provisions addressing the research

agenda for onroad and non-road sources in the proposed rule itself, otherwise

there will be no explicit commitment to carry out this research. It is essential

that EPA make a clear regulatory commitment to perform a comprehensive risk

characterization and control determination regarding the collective emissions

from road and non-road mobile sources and their fuels. EPA should follow

through with the commitments to conduct a comprehensive assessment by

placing them in the regulatory text of the final rule.

Letters:

NESCAUM (IV-D-10) p. 3, 15-16

NESCAUM (IV-F-1) p. 24-26

STAPPA, ALAPCO (IV-D-22) p. 4
Response to Comments

December 20, 2000

Page 122

STAPPA, ALAPCO (IV-F-1) p. 48-49

(6) It is very important that EPA continues periodically to assess the effect that the

proposed rules have on concentrations of mobile toxics nationwide and their

impacts on public health, particularly children's health. Commenter agrees that

a 3-year cycle for conducting ongoing assessments as proposed by a second

commenter may be appropriate.

Letters:

American Lung Association of Michigan (IV-F-1) p. 74-75

Michigan Environmental Council (IV-F-1) p. 69

Response to issues 7(A)(1) through (6): We are committed to conducting a

Technical Analysis Plan that will include development of

emission factors for nonroad sources analysis of

toxics exposures in microenvironments and examination of

additional fuel and vehicle based air toxics controls

for both motor vehicles and nonroad engines and equipment

We recognize the need to conduct additional work and to

focus on relevant scientific data to address the needs

we outline in the Technical Analysis Plan The issues

outlined are complex and while the work conducted as part

of the Technical Analysis Plan will begin to address the

significant data gaps resolution of some aspects of

these issues will require a long term effort This

effort will be coordinated across the Agency to maximize

available resources It is important to note that the Technical

Analysis Plan will not answer all relevant questions regarding the potential

impacts of mobile sources on public health risks due to exposure to toxic

compounds. The Technical Analysis Plan will provide important pieces of the

key studies necessary to help evaluate potential risks associated with several

important Mobile Source Air Toxics.

The Agency has made a regulatory commitment to reevaluate the need for and

technical feasibility of additional controls on on-highway mobile sources in the

2003-2004 timeframe. That re-evaluation will, by necessity, require significant

allocation of resources to attempt to fill data gaps identified in the Technical

Analysis Plan. Over the past several years, the Agency has redirected

significant resources to better understand ambient concentrations, exposure

and risk associated with air toxics from all sources, including mobile sources. 

Examples include the Cumulative Exposure Project which estimated ambient

concentrations of air toxics for the calendar year 1990, and the ongoing National

Air Toxics Assessment National-Scale Analysis which analyzes 1996 ambient

concentrations and inhalation exposures, and also conducts a characterization

of inhalation risks. The Agency fully intends to use these important previous

studies as screening tools to direct our future efforts in air toxics assessments. 

While it is inappropriate to place the Agency’s Technical Analysis Plan as
Response to Comments

December 20, 2000

Page 123

articulated in the preamble into the actual regulatory document, the Agency

commitment to the Technical Analysis Plan is real and its commitment to a

future rulemaking is identified in the regulatory document. 

We have an ongoing relationship with HEI that may be used as we

collect and analyze information to determine which pollutants

might be of public health concern In addition we will use

information from the Agency s National Air Toxics

Assessment Program The Agency plans to periodically update this

assessment. This would include revisions to the National Toxics Inventory and

the National-Scale Analysis based on newly available information. 

The Agency has developed a strategy for research on environmental risks to children. 

For more information see: http://www.epa.gov/nceawww1/risk2kids.htm.

(B) EPA fails to describe a research plan to continue to analyze MSATs.

(1) EPA has vaguely described data gaps without any serious plan to address

those gaps. Without a detailed research plan, the Agency will be in the same

position in 2004 as it is now. It is not even clear that the Agency requested

funding for NATA activities. Commenter notes that EPA should not rely on the

public to conduct this sort of research, and EPA should not settle for a handful

of poorly funded and limited tests to comprise its understanding of MSATs and

their health effects. Engine and vehicle manufacturers should be required to

conduct emissions testing of on-road and nonroad engines to fill the information

void.

Letters:

Consumer Policy Institute (IV-D-8) p. 3

Response to issue 7(B)(1): We have described a research plan to address the most critical

data gaps in our understanding of the potential health impacts of public

exposure to air toxics from mobile sources. We are coordinating work

underway within and outside the Agency regarding exposure monitoring,

modeling, and emissions characterization to provide the most comprehensive

analysis available in the 2003-2004 timeframe. As discussed above (Response

to issue on issue 7, section (A)(1) through (A)(6)), the issues outlined

are complex and while the work conducted as part of the

Technical Analysis Plan will begin to address the

significant data gaps resolution of some aspects of

these issues will require a long term effort The Agency

continues to direct significant resources to better

understand ambient concentrations exposure and risk

associated with air toxics from all sources including

mobile sources as evidenced by the National Air Toxics

Assessment The Agency has also developed the

Integrated Urban Air Toxics Strategy and is working on
Response to Comments

December 20, 2000

Page 124

development of an Air Toxics Research Strategy These

long-term efforts will provide substantial information on which to base future

regulatory decisions.

(C) EPA needs to modify the proposed treatment of non-road engines in the TAP.

(1) More information regarding air toxic emissions from non-road sources is

needed. Commenter supports EPA's decision to develop a TAP to study nonroad sources' contribution to ambient conditions because it makes sense to

gather the needed information before acting to establish controls that might not

be needed or would not be effective. Another commenter, however, argued that

the timeframe for the TAP was inconsistent with analyzing emissions from nonroad engines. There are a number of regulatory efforts that will affect emissions

from non-road engines, and EPA should wait until those requirements take

effect before attempting to study toxic emissions from non-road engines.

Letters:

Engine Manufacturers Association (IV-D-39) p. 7, att.

Engine Manufacturers Association (IV-F-1) p. 16-17

North American Equipment Dealers Association (IV-D-37) p. 2

Response to issue 7(C)(1): We currently have very little data regarding the emissions of

toxic compounds from nonroad sources. We are in the process of gathering

this information to assess the impact of these emissions on national and local

inventories, ambient concentrations, exposures and ultimately on the risk to the

public. We disagree that collection of this information can wait since the

information is needed to determine the need for additional regulatory controls

and to establish an understanding of baseline emissions.

 

(2) More research is needed to identify feasible and cost effective control

technologies applicable to the different and difficult demands of non-road

engines. Commenter notes that any study of nonroad emissions must

individually subcategorize the different categories of nonroad engines due to

significant differences in engine structure, fuel, and performance.

Letters:

North American Equipment Dealers Association (IV-D-37) p. 2

(3) At a minimum, small land-based SI engines should be excluded from further

study because these sources are an insignificant source of toxic emissions,

especially after considering recent regulatory controls on these sources.

Letters:

North American Equipment Dealers Association (IV-D-37) p. 3
Response to Comments

December 20, 2000

Page 125

Responses to issues 7(C)(2) and (3): We agree that additional research is needed to

identify feasible and cost effective control technologies applicable to nonroad

engines and we are currently looking into control area network devices,

electronic control and feedback of engine operations, and exhaust gas recirculation. As with our current regulatory program for non-road engines, an

assessment of emissions from these engines is broken into categories based

on the horsepower of the engine. We are not determining a priori which, if any

engines will be excluded from further study. 

(D) VOCs are on the decline, and EPA should assume that other MSATs are on the

decline as well. Therefore, EPA should consider whether it is cost-effective to

carry on with a study of non-road engines as indicated in the proposal.

(1) If EPA sees a correlation between VOCs and other gaseous MSATs, then this

proposed rule should be withdrawn. If EPA follows through with this rule and

the study, then the MSATs should be studied and listed specifically in relation to

each non-road engine category. 

Letters:

North American Equipment Dealers Association (IV-D-37) p. 3

Response to issue 7(D)(1): In order to understand the potential public health impact of

emissions of toxic compounds from nonroad engines we need to understand the

specific chemical composition of the VOCs emitted and our Technical Analysis

Plan includes work that will provide this information. MSATs studied will be

determined based on the type of engine, horsepower of the engine tested, and

operating conditions. These tests results will be extrapolated to other engines

as appropriate.

(E) EPA must also address indoor sources of toxics.

(1) From an exposure and risk perspective, toxics generated by indoor sources may

likely be the most important health concern, especially since people spend

nearly 90% of their time indoors. Because of their importance, it is imperative

that EPA incorporate and integrate indoor air toxic exposures into the TAP,

UAT, and NATA assessments.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 6

Alliance of Automobile Manufacturers (IV-F-1) p. 63

Response to issue 7(E)(1): We agree with the commenter that more research is needed. 

The Agency plans to assess the emissions of toxic compounds by indoor

sources and ultimately to assess the overall impact of these sources on

exposure. The Office of Radiation and Indoor Air is currently developing an

indoor air toxics strategy.
Response to Comments

December 20, 2000

Page 126

15Winebrake et al. 2000. Fuel Cycle Emissions for Conventional and Alternative Fuel

Vehicles: An Assessment of Air Toxics. Department of Energy, Center for Transportation

Research, Argonne National Laboratory. Report No. ANL/ESD-44.

(F) EPA should address emissions toxicity of other fuel/vehicle types.

(1) EPA needs to include analysis of other vehicle/fuel types (Such as CNG) to

evaluate toxics emissions from these vehicles. Policymakers often mistakenly

assume alternative fueled vehicles have zero toxic emissions. More research

on this issue is necessary so that future diesel technology can compete fairly

with other alternative technologies in producing ultra-low engine emissions.

Letters:

Tosco (IV-D-41) p. 2

Response to issue 7(F)(1): We agree with the commenter that analysis of the toxic

emissions from alternative fueled vehicles is important and we do not make the

assumption that alternative fueled vehicles have no toxic emissions. We agree

that additional research is necessary on this issue and we will follow the results

of this work. The Department of Energy, Center for Transportation Research is

doing work in this area, and has recently released an assessment of fuel cycle

emissions for conventional and alternative fueled vehicles.15 The Agency is

evaluating the implications of this work.

(G) The proposed rulemaking should have included a provision for monitoring of

HAP emission reductions.

(1) By establishing a system of monitoring sites in cities throughout the country, and

comparing actual HAPs monitoring data to predictions of emissions reductions,

EPA could have the ability to evaluate the effectiveness of various control

programs and strategies on an on-going basis. If such a proposal was included

as part of this rulemaking, more information would be available in 2004. 

Another commenter generally supports increased monitoring of HAPs to assist

EPA's ongoing evaluations of MSATs.

Letters:

Consumer Policy Institute (IV-D-8) p. 3

Michigan Environmental Council (V-F-1) p. 69

Response to issue 7(G)(1): We agree that a system of monitoring sites throughout the

country would be beneficial. We are providing funds for some such studies to

be initiated in ten areas of the U.S. (Providence, RI, Seattle, WA, Tampa Bay,

FL, Detroit, MI, San Jacinto, CA, Grand Junction, CO, Cedar Rapids, IA, Rio

Rancho, MN, Charleston/Huntington, WV, and San Juan/Barceloneta, PR).

However evaluation of the effectiveness of control options

using these data over short time periods e g between now
Response to Comments

December 20, 2000

Page 127

and is not possible Year to year variations in

meteorology alone can cause ambient air concentrations to

vary widely making an interpretation of a trend over a

short period very difficult to interpret
Response to Comments

December 20, 2000

Page 128

ISSUE 8: PROPOSED FUTURE RULEMAKING 

(A) EPA should include in the final rule a commitment to study MSATs and to

promulgate further rules.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Puget Sound Clean Air Agency (IV-D-27) p. 2

Response to issue 8(A)(1): The rule satisfies the commenter’s request.

(B) Commenter concurs with EPA's assessment, reflected in section 80.825 that it

may be appropriate to revisit emissions of HAPs from mobile sources in 2003.

(1) Commenter supports EPA's proposal to limit only benzene at the current time,

and determine in 2003 whether additional controls may be warranted at that

time.

Letters:

International Truck and Engine Corp. (IV-D-30) p. 3

Response to issue 8(B)(1): We agree. Although we have changed the control from a

benzene content standard to a toxics performance standard, we have

maintained the same general approach in setting a near-term anti-backsliding

standard and committing to further investigate long-term controls.

(C) Because they are significant contributors to MSATs, EPA should address in its

future rulemaking the pollution from non-road engines and vehicles.

(1) As on-road standards are phased in, non-road sources will become increasingly

significant contributors to MSATs. EPA needs to articulate a detailed plan for

addressing these sources.

Letters:

Clean Air Network, et al (IV-D-38) p. 4

Consumer Policy Institute (IV-D-8) p. 4

Response to issue 8(C)(1): The final rule articulates a plan to address emissions from

nonroad sources.

(2) EPA's intent to include those sources in the future should be stated clearly in

the final rule.

Letters:
Response to Comments

December 20, 2000

Page 129

Commonwealth of MA DEP (IV-D-13) p. 2

STAPPA, ALAPCO (IV-D-22) p. 5

Response to issue 8(C)(2): The final rule clearly states the Agency’s intent to address

emissions from nonroad sources in a future rule.

(D) EPA has predetermined the need for a rulemaking before it has evaluated the

underlying facts.

(1) It is inappropriate to publish a schedule for future rulemaking after declaring

EPA lacks sufficient information to support a future rulemaking. EPA should

study toxics, determine the need for a rulemaking, and only then establish a

timetable.

Letters:

American Petroleum Institute (IV-D-21) p. 5-6

American Petroleum Institute (IV-F-1) p. 38

ExxonMobil (IV-D-16) p. 8-9

Koch Petroleum Group (IV-D-36) p. 3

Marathon Ashland Petroleum, LLC (IV-D-15) p. 2, 6-7

Murphy Oil Corporation (IV-D-17) p. 6

Phillips Petroleum Company (IV-D-20) p. 4

Response to issue 8(D)(1): EPA has sufficient reason for concern about the potential risks

related to air toxics to commit to a future rulemaking in 2003-2004. However,

our commitment to that future rulemaking is to reevaluate the need and

technical feasibility of additional controls on mobile source air toxics. The action

we take at that time will depend on the results of the research we will undertake

as part of our Technical Analysis Plan. Based on that analysis, if no controls

are deemed appropriate for on-highway vehicles or fuels, the rulemaking will

confirm that the existing controls satisfy the criteria in Section 202(l)(2) of the

Act.

(2) EPA should not commit to a further rulemaking in 2004 until it analyzes the air

toxics research conclusions to determine the need for another rulemaking. EPA

should examine and assess new information regarding the proposed rule at

some time in the future. However, the timing of such a review and the need for

additional rulemaking should be based upon the Agency's continuing evaluation

and monitoring of MSAT trends as well as the results of the TAP. The TAP

should be completed and all information reviewed to determine if there is a need

for any additional rulemaking. If a need is identified, a rulemaking can be

initiated at that time. Otherwise, additional data from the studies may show there

is no need for a rule, and yet the commitment would otherwise still exist.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 9

Alliance of Automobile Manufacturers (IV-F-1) p. 65
Response to Comments

December 20, 2000

Page 130

Engine Manufacturers Association (IV-D-39) p. 7-8, att.

Response to issue 8(D)(2): As discussed in the response to the previous issue, the

commitment we are making in this fule rule is to reevaluate the need and

technical feasibility of additional controls on mobile source air toxics. The

Agency is not committing to promulgate new controls. If no controls are

deemed appropriate for on-highway vehicles or fuels, the rulemaking will

confirm that the controls promulgated at that time satisfy the criteria in Section

202(l)(2) of the Act. The decision to regulate will depend on the outcome of

future data analysis and research.

(E) EPA's proposal to engage in a future rulemaking cannot satisfy the

requirements of CAA section 202(l).

(1) The text and the legislative history of the CAA contemplate that additional,

aggressive action be taken to address MSATs in the current rulemaking.

Letters:

Environmental Systems Products (IV-D-25) p. 12-13

Response to issue 8(E)(1): The Agency agrees that a commitment to a future rulemaking

does not satisfy its requirements under section 202(l). The Agency views its

obligation under 202(l) as requiring a periodic reevaluation of the need for and

technical feasibility of additional controls on motor vehicles. 

(F) EPA does not have the authority under section 211(c) or any other provision of

the CAA to promulgate a rule establishing deadlines for future administrators

to conduct rulemakings.

(1) The commenter points to several examples to document that where Congress

intends for the statute to impose deadlines, Congress specifies the deadline in

the statute. EPA cannot in this rulemaking do what Congress has specifically

chosen not to do.

Letters:

American Petroleum Institute (IV-D-21) p. 6

Response to issue 8(F)(1): We disagree. The regulatory commitment in section 80.825 of

the regulations is reasonable and entirely within EPA’s authority. Nothing in the

Clean Air Act limits EPA’s discretion to set timetables for itself to complete nonmandatory regulatory actions, so long as those timetables are consistent with

any mandatory statutory deadlines. One example of a similar regulatory

deadline EPA has imposed on itself is codified at 40 C.F.R. § 86.004-

11(a)(1)(i)(E) (setting schedule for regulatory review of the on-highway heavyduty engine standards).

(G) Opposes the proposed timeline for the future rulemaking.
Response to Comments

December 20, 2000

Page 131

(1) EPA lacks statutory authority to extend a rulemaking deadline that it has already

failed to meet.

Letters:

National Petrochemical and Refiners Association (IV-D-33) p. 4

Response to Issue 8(G)(1): As noted in the response to issue 2.1(A)(1), EPA has a

continuing obligation under the statute to periodically revise regulations

established pursuant to Section 202(l)(2). Section 202(l)(2) clearly states that

EPA shall “promulgate (and from time to time revise” regulations...” In other

words, Congress intended EPA to consider control of emissions of hazardous

air pollutants from motor vehicles and their fuels as an ongoing air pollution

issue. 

(2) The proposed two-year study schedule does not provide sufficient time for EPA

to adequately assess the impacts of existing and upcoming controls on toxic

emissions.

Letters:

American Petroleum Institute (IV-D-21) p. 6

Response to issue 8(G)(2): The agency routinely projects emissions reductions from

control programs that have not been fully implemented. Today’s rule quantifies

expected future reductions, and we will be able to do so in two years as well. 

Moreover, in the next two years, we will have better information on inventory,

exposure, and risk, since we will be focusing on acquiring this information as

part of our Technical Analysis Plan.

(3) EPA should amend their schedule so that final standards for both on- and nonroad sources are promulgated by June 2004.

Letters:

Commonwealth of MA DEP (IV-D-13) p. 2

STAPPA, ALAPCO (IV-D-22) p. 3

Response to issue 8(G)(3): The final rule establishes July 1, 2004 at the date for final

promulgation of the rule for on-highway controls as appropriate. We have also

explained in the regulation that during this rulemaking EPA intends to evaluate

emissions and potential control strategies relating to hazardous air pollutants

from nonroad engines and vehicles.

(4) EPA should continue to study the issue and plan to propose additional rules by

the end of 2001. Also, EPA should establish a three-year cycle for reviewing

the rule's impact and the need for strengthening it.

Letters:
Response to Comments

December 20, 2000

Page 132

Clean Air Network, et al (IV-D-38) p. 5

Response to issue 8(G)(4): The Agency has established an ambitious research agenda in

the rule. The Agency does not believe that is would be appropriate or

reasonable to shorten the time period alloted for additional research and

analysis prior to the next rulemaking. It is premature to commit the Agency to a

three-year cycle of review for the mobile source air toxics rule until we gain a

more robust appreciation of the risks attributable to air toxics.

(H) Small land-based SI engines should be excluded from all further rulemakings.

(1) It is not cost-effective to continue to spend money studying or regulating

insignificant contributors of emissions.

Letters:

North American Equipment Dealers Association (IV-D-37) p. 2-3

Response to issue 8(H)(1): These engines may play an important role in contribution to

personal exposure to air toxics despite the fact that their contribution to national

inventories is relatively low. As part of the TAP, we will determine which

pollutants and categories of new nonroad engines are appropriate for further

controls.
Response to Comments

December 20, 2000

Page 133

ISSUE 9: COMMENTER SUPPORTS OTHER'S COMMENTS 

(A) Commenter supports comments made by API.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Chevron (IV-D-34) p. 1

Citgo Corporation (IV-D-5) p. 1

ExxonMobil (IV-D-16) p. 10

Marathon Ashland Petroleum, LLC (IV-D-15) p. 1

Phillips Petroleum Company (IV-D-20) p. 5

Response to issue 9(A)(1): No response required.

(B) Commenter supports comments made by NPRA.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Marathon Ashland Petroleum, LLC (IV-D-15) p. 1

Phillips Petroleum Company (IV-D-20) p. 5

Response to issue 9(B)(1): No response required.

(C) Commenter supports comments made by STAPPA/ALAPCO.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Commonwealth of MA DEP (IV-D-13) p. 1

(2) Commenter supports STAPPA/ALAPCO hearing testimony.

Letters:

Puget Sound Clean Air Agency (IV-D-27) p. 1

Response to issue 9(C)(1) and (2): No response required.

(D) Commenter supports comments made by NESCAUM.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:
Response to Comments

December 20, 2000

Page 134

Commonwealth of MA DEP (IV-D-13) p. 1

Response to issue 9(D)(1): No response required.

(E) Commenter supports comments made by EMA.

(1) Commenter provides no further supporting information or detailed analysis.

Letters:

Alliance of Automobile Manufacturers (IV-D-11) p. 5

International Truck and Engine Corp. (IV-D-30) p. 1

Response to issue 9(E)(1): No response required.

(2) Commenter supports EMA's hearing testimony generally.

Letters:

Detroit Diesel (IV-F-1) p. 75

Response to issue 9(E)(2): No response required.