3/8/12

Screening Consideration of Four EPA Proposed Regulatory Actions 

and Supporting Science

Background: 

EPA has a new initiative to strengthen coordination with the Science Advisory Board (SAB) by 

providing the SAB with information about proposed agency actions (Attachment A). The process is 

intended to provide the SAB a meaningful opportunity to provide advice and comment, where 

appropriate, on the science supporting proposed agency actions. As the SAB develops an 

implementation process for this initiative, the SAB is conducting a pilot exercise to evaluate four 

proposed rules to determine whether or not the SAB wishes to provide advice and comment on the 

supporting science. The pilot exercise also will help the SAB to identify the types of information that it 

would need from the agency in the future in order to determine which proposed actions have scientific 

issues that should receive formal SAB review. 

SAB Pilot Process:

On December 23, 2011, the SAB Staff Office was informed by EPA’s Office of Air and Radiation of

proposed rules relating to (1) standards for air toxics from boilers and incinerators and (2) greenhouse 

gas emissions and fuel economy standards for light-duty vehicles (see Attachment B). Consistent with 

the SAB’s charge under the Environmental Research, Development and Demonstration Authorization 

Act (ERDDAA), the SAB will discuss whether or not it wishes to provide advice and comment to the 

agency on the science supporting these rules.

To assist the SAB deliberations, SAB members Drs. David Allen, Peter Thorne and Jerry Schnoor 

agreed to serve as lead discussants. In that capacity, they have worked with SAB staff to conduct factfinding (Attachments F, G and H) and have developed initial recommendations (Attachment C) to the 

chartered SAB on whether the SAB should develop advice and comment relating to the OAR proposed 

rules. Historical SAB evaluation criteria (Attachment D) were considered in the screening process.

During the March 22-23, 2012 meeting, the chartered SAB will hear public comments, consider the 

recommendations from the SAB lead discussants, and consider whether it wishes to offer advice and 

comment on the adequacy of the scientific and technical basis of the proposed agency actions.

CONTENTS OF THIS PACKET

Attachment A. Coordination with the Science Advisory Board Regarding Proposed Criteria 

Documents, Standards, Limitations and Regulations (Memorandum from 

Michael Goo, Associate Administrator for Policy)................................... 2

Attachment B. Summary of Four EPA Proposed Rules from December 2011 .................... 4

Attachment C. Recommendations for SAB Consideration from Lead Discussants ............... 5

Attachment D. SAB Evaluation Criteria .................................................................... 11

Attachment E. EPA’s Air Toxics Standards Major and Area Source Boilers and Certain 

Incinerators: Overview of Changes and Impacts (EPA Fact Sheet) ................ 12

Attachment F. Summary of Fact-Finding Meeting on Scientific and Technical Issues for EPA 

Proposed Rules Relating to HAPs Emission Standards for Boilers and 

Incinerators (SAB Staff Office Summary)............................................ 16

Attachment G. Science Topics Raised by Commenters at Public Hearings for Light-Duty 

2017-2025 GHG and CAFE Standards NPRM (EPA Staff Draft Summary) ... 20

Attachment H. Peer Reviewed EPA Studies Utilized in the LD 2017-2025 GHG and CAFE 

Standards NPRM (EPA Staff Summary) ............................................. 22
2

Attachment A. 
3
4

Attachment B. Summary of Four EPA Proposed Rules from December 2011

Regulatory Action and Fact 

Sheets

Status Public 

Comments 

Due

Affected Parties Supporting Technical 

documents

Commercial and Industrial 

Solid Waste Incineration 

(CISWI) Units: 

Reconsideration and Proposed 

Amendments; Non-Hazardous 

Secondary Materials That Are 

Solid Waste

• Fact Sheet: CISWI

• Fact Sheet: NHSM

Proposed Rule

Pages 80452 -

80530 [FR DOC 

# 2011-31648]

02/21/12

(60 days)

Commercial or 

industrial facilities with 

devices that burn solid 

waste (incinerators, 

energy recovery units, 

waste burning kilns)

http://www.epa.gov/ttn/atw/

boiler/boilerpg.html#TECH

National Emission Standards 

for HAPs for Area 

Sources: Industrial, 

Commercial, and Institutional 

Boilers

• Fact Sheet: Area 

Sources

Proposed Rule 

76 FR 80532-

80552

(12/23/11)

02/21/12

(60 days)

Facilities using boilers 

fired by oil, biomass, or 

coal: (1) industrial 

boilers, and (2) 

commercial and 

institutional boilers

National Emission Standards 

for Hazardous Air Pollutants 

for Major Sources: Industrial, 

Commercial, and Institutional 

Boilers and Process Heaters

• Fact Sheet: Major 

Sources

Proposed Rule

Pages 80598 -

80672 [FR DOC 

# 2011-31667]

02/21/12

(60 days)

Industries using boilers 

or process heaters 

located at major sources 

of HAPs

EPA and DOT’s Proposed 

Light-duty GHG and CAFE 

Vehicle Standards

• Fact Sheet

Proposed Rule

Pages 74854-

75420 [FR DOC 

# 2011-30358]

02/13/12

(extended 

from 

01/30/2012)

Motor vehicle 

manufacturers, 

importers of vehicles or 

vehicle components, 

alternative fuel vehicle 

converters

http://epa.gov/otaq/climate/r

egulations.htm#1-1
5

Attachment C. Recommendations for SAB Consideration from Lead Discussants

1. “The Boiler/Incinerator MACT Reconsideration Proposal” 

(SAB Fact-Finding Leads: Drs. Allen and Thorne)

Background: On March 21, 2011, the EPA promulgated 4 final rules that set national emission 

standards for control of hazardous air pollutants from industrial, commercial and institutional boilers at 

major and area source facilities, revised the definition of non-hazardous secondary material (NHSM) to 

clarify the scope of biomass and other solid wastes used as fuels, and emissions from commercial and 

industrial solid waste incineration (CISWI) units. At that time, the agency announced its intention to 

reconsider certain portions of the final standards to consider additional issues and public comments.

EPA Proposed Action: On December 23, 2011, the agency proposed a limited number of amendments 

to the 4 final rules, with public comments due within 60 days (i.e., by February 21, 2012). The proposed 

amendments for the set of rules are summarized in an EPA overview fact sheet (Attachment E).

Supporting Technical Documents: Regulatory and technical background information for the boiler 

rules for major and area sources is provided at http://www.epa.gov/ttn/atw/boiler/boilerpg.html#TECH, 

including documents specific to the proposed reconsideration. Technical issues include the timing of 

compliance tune-ups for seasonal boilers, fuel-specific PM emission limits, new CO emissions limits, 

and replacing numeric dioxin emissions limits with work practice standards.

SAB Screening Analysis and Recommendation:

In addition to the proposed rule and the summary factsheet, EPA provided additional information 

requested by Drs. Allen and Thorne in a fact-finding telephone call (meeting summary, Attachment F). 

Science and technical issues associated with the EPA proposed action, and relevant evaluation criteria 

that would suggest that the SAB review and comment on these issues, are summarized in the tables

below. 

1a. HAPS for Boilers at Major and Area Sources

Proposed Rule Underlying Science/Technical Issues Evaluation Criteria

HAPS for Boilers at 

Major Sources

• Large risk reduction 

• Large numbers of impacted facilities 

• Replacement of required dioxin 

measurements with workplace practice 

requirements 

involves major 

environmental risks; 

supports major regulatory or 

risk management activities

involves scientific 

approaches that are new to 

the agency

addresses areas of substantial 

uncertainty

requires the commitment of 

substantial resources to 

scientific or technological 

development

HAPS for Boilers at 

Area Sources

• Large risk reduction 

• Large numbers of impacted facilities 

involves major 

environmental risks; 
6

• Replacement of required dioxin 

measurements with workplace practice 

requirements 

supports major regulatory or 

risk management activities

involves scientific 

approaches that are new to 

the agency

addresses areas of substantial 

uncertainty

requires the commitment of 

substantial resources to 

scientific or technological 

development

Recommendation to the chartered SAB: 

I reviewed documents related to the rules on Boilers (both major source and area source). These are 

major rules with large estimated air quality and risk reduction benefits, and with large populations of 

impacted facilities. Thus, both rules meet at least two of the criteria for SAB activities (“involves major 

environmental risks”; “supports major regulatory or risk management activities”). However, if these 

criteria alone are applied to the selection of regulations for the SAB to examine, the number of rules that 

the SAB would need to review would be large. 

Therefore, in reviewing the regulations, I also focused on additional criteria for SAB activities 

(“involves scientific approaches that are new to the agency”, “addresses areas of substantial 

uncertainty”, and “requires the commitment of substantial resources to scientific or technological 

development”). In both of the rules that I examined, there are scientific issues underlying the regulations 

that may meet these criteria. One example (and there could be others) is the replacement of required 

dioxin emission measurements with the use of certain workplace practices. It would require additional 

review by individuals with expertise in flame chemistry, boiler practices and analytical methods to 

determine the relative significance of the scientific issues related to this part of the rule.

The lessons I learned from this exercise are:

• All major rules and regulations would satisfy some of the criteria for SAB activities. The Board 

will need to perform a relative ranking of rules in determining which should be reviewed by the 

Board, rather than simply determining whether rules meet one or more criteria for Board 

activities. The number of rules that could be examined would depend on the resources available 

to the Board.

• The review of rules and regulations will likely need to be at least a three step process, with an 

initial screening by the Board followed by more detailed analysis by individuals with regulationspecific scientific expertise to refine the Board’s understanding of the scientific issues, and 

ending with possible review of the scientific issues underlying some of the rules and regulations. 

David Allen, SAB Member
7

1b. Rules for CISWI and NHSM

Proposed Rule Underlying Science/Technical Issues Evaluation Criteria

Amendments to the New 

Source Performance 

Standards and Emission 

Guidelines for CISWI* Units

*Commercial and Industrial 

Solid Waste Incineration

Proposed reconsiderations would produce 

significant reductions in toxic air emission, 

including mercury and soot.

MACT Floor Limits are established for nine 

pollutants across six subcategories of CISWI 

Units (year 2000 limits were for “incinerators”). 

The new limits are more restrictive for all but 

“small, remote incinerators.”

Supports EPA strategic 

priorities (reduction of air 

toxics emissions)

Involves major environmental 

risks (Hg, Pb, Cd, PM2.5, 

dioxins & furans, NOX, SO2, 

HCl and CO)

Revisions to the Final Rule 

on Identification of NonHazardous Secondary 

Materials (NHSM) that are 

Solid Wastes

New information has emerged that will facilitate 

implementation of rules as originally intended.

Clarification was needed as to what constitutes a 

non-waste fuel (e.g., clean cellulosic biomass, tires 

managed under tire collection programs, etc.)

Supports EPA strategic 

priorities (to simplify 

regulations and facilitate 

compliance)

Recommendations to the chartered SAB:

CISWI Units

Background:

CISWI Units include incinerators, energy recovery units (ERUs), waste burning kilns and small remote 

incinerators. Amendments to the New Source Performance Standards and Emission Guidelines for 

Commercial and Industrial Solid Waste Incineration (CISWI) Units center on four revisions:

• Revise some monitoring requirement to add flexibility and reduce costs of compliance.

• Revise emission limits to reflect updated inventories.

• Change corrections of CO emissions during startup and shutdown.

• Clarification of what units are defined as CISWI units.

There are many more CISWI Units than EPA knew about in March 2011 and some types EPA had not 

considered. New and existing source MACT floor limits are established for nine pollutants across six 

subcategories of CISWI Units (year 2000 limits were for “incinerators”). The new limits are more 

restrictive for all but “small, remote incinerators. All limits are measured at or corrected to 7% oxygen. 

The nine pollutants are: HCl, CO, Pb, Cd, Hg, PM, dioxins & furans, NOX and SO2. The six CISWI Unit 

subcategories are: incinerators, ERUs-coal, ERUs-biomass, waste burning kilns, small remote 

incinerators. These rules exclude cyclonic burn barrels, burn-off units, soil treatment units, lab analysis 

units and space heaters. 

Estimated compliance costs are $859 million capital investment and $270 million annual outlay. 

Estimated health benefits are $330 to $800 million in 2015 for reduction of PM2.5 with comparable 

benefits thereafter.

Recommendation:

These revisions seem appropriate and responsive to additional data supplied by regulated CISWI Unit 

operators. I do not find that these revisions significantly meet the criteria for SAB advisory activities. 

Thus, I recommend that the Science Advisory Board not undertake further review of this set of revisions 

to the March 2011 rules.
8

Identification of NHSM

Background:

Revisions to the Final Rule on Identification of Non-Hazardous Secondary Materials (NHSM) that are 

Solid Wastes include the following:

• Definition of Clean Cellulosic Biomass to include e.g., crop residues, wood debris, untreated 

wood pallets.

• Allow operators to petition to have EPA accept a NHSM as a non-waste fuel.

• Identification of resinous wood and tires managed under other programs as non-wastes when 

used as fuel.

• Facilities burning fuels from different categories (e.g., coal and biomass) can use facilities that 

burn either one alone for comparison.

Recommendation:

These proposed revisions to the March 2011 rules provide clarification to facilitate implementation of 

rules as originally intended. The available science supports these revisions on a long-standing 

environmental issue. I recommend that the Science Advisory Board not undertake further review of this 

set of revisions to the March 2011 rules.

Peter Thorne, SAB Member
9

2. Proposed Light-Duty Vehicle Greenhouse Gases (GHG) and CAFE Vehicle Standards

(SAB Fact-Finding Lead: Dr. Schnoor)

Background: In a 2007 ruling, the U.S. Supreme Court concluded that “greenhouse gases fit well within 

the Clean Air Act’s capacious definition of ‘air pollutant’” and that the EPA has authority under CAA 

Section 202(a) “to regulate GHG emissions from new motor vehicles in the event that it forms a 

‘judgment’ that such emissions contribute to climate change.” Thus, the authority to establish GHG 

emissions standards for vehicles under the Clean Air Act was a result of EPA’s December 7, 2009, 

findings that current and projected concentrations of 6 GHG in the atmosphere threaten the public health 

and welfare of current and future generations (the Endangerment Finding) and that emissions from 

vehicles contribute to GHG pollution (see http://www.epa.gov/climatechange/endangerment.html).

Authority to set Corporate Average Fuel Economy (CAFÉ) Standards rests with the National Highway

Traffic Safety Agency (NHTSA).

On April 1, 2010, EPA and the National Highway Traffic Safety Agency (NHTSA) issued standards for 

GHG and fuel economy for 2012-2016 model year light-duty vehicles and for 2014-2018 model year 

heavy-duty vehicles (e.g., heavy-duty pickup trucks, vans and buses) on August 9, 2011. This National 

Program allows vehicle manufacturers to develop one fleet that would satisfy both the national and 

California requirements. (California set GHG standards for light-duty vehicles in 2004 and these 

standards have been adopted by 13 states and D.C.)

EPA Proposed Action: On December 1, 2011, the EPA and NHTSA issued a proposed rule to extend 

the National Program of light-duty vehicle GHG emissions and corporate average fuel economy (CAFE) 

standards to model years 2017–2025. The proposed rule would set GHG emissions and fuel economy 

standards on the basis of vehicle size (or “footprint”), with larger vehicles held to less stringent 

standards than smaller vehicles and with standards becoming more stringent in each model year.

Supporting Technical Documents: regulatory and technical background documents are provided at 

http://www.epa.gov/otaq/climate/regulations.htm and include the Draft Joint Technical Support 

Document (November 2011) and the Draft RIA (November 2011). Technical analytical issues include 

the build-up of the baseline and reference fleets, the derivation of the shape of the footprint-based 

attribute curves, estimated costs and effectiveness of vehicle technologies, and estimation of costs and 

benefits of the proposed rules.

SAB Screening Analysis and Recommendation:

In addition to the proposed rule and summary factsheet, EPA provided additional information requested 

by Dr. Schnoor to summarize technical issues raised at three public hearings on the proposed rule 

(Attachment G) and to summarize the peer review of technical documents that support the rule 

(Attachment H). Science and technical issues associated with the EPA proposed action, and relevant 

evaluation criteria that would suggest that the SAB review and comment on these issues, are 

summarized in the table below. 
10

Proposed Rule Underlying Science/Technical Issues Evaluation Criteria

GHG/fuel economy 

standards for 2017-

2025 model year lightduty vehicles 

• Endangerment Finding 2009 

• Cause & Contribute Finding

• EPA + NHTSA Joint Proposal 2010

• GHG + CAFÉ Stds (both required?)

Major envir. risks

Major regulatory initiative

Transcends org boundary

Making difference in 

science; model for future

• 1st GHG regs for Heavy Duty Vehicles HDV Major regulatory initiative

• Net Benefit Calculations (Benefit:Cost) Model for future methods

• Advanced Tech Credits for EVs & PHEVs 

Zero CO2 equiv/mi emissions 2012-16

Area of substantial 

uncertainty

Recommendation to the chartered SAB: Pursuant to the SAB Criteria for Advisory Activities, these 

GHG/fuel economy standards represent a major regulatory initiative at the specific charge of The 

President of the United States, and in keeping with the 2007 Supreme Court ruling in Massachusetts v. 

EPA, the EPA Endangerment and Cause/Contribute Findings of 2009, the Clean Air Act, and the Energy 

Independence and Security Act of 2007. It also represents a good example of EPA working with another 

agency on a major regulatory initiative, the National Highway Traffic Safety Administration (NHTSA) 

to produce a new generation of clean vehicles through reduced GHG emissions and improved fuel use 

from on-road vehicles and engines. 

However, the recent November 2011 proposed rules for 2017-2025 are mostly an extension of the 

previous rule (April 1, 2010) establishing standards for 2012-2016 model year vehicles. There is not 

new science or technical issues with the possible exception of the advanced technical credits for electric 

vehicles and (partially) plug-in electric vehicles (PHEVs) that are being proposed in which incentives 

are provided for a quota of vehicles at 0 g CO2 equivalents/mile. This is somewhat controversial because 

a life cycle analysis would show that these vehicles obtain electrical charge from the grid which 

certainly causes greenhouse gas emissions. But EPA has proposed this as an incentive to facilitate 

market penetration of the most advanced vehicle technologies as rapidly as possible, so it is touted as an 

economic incentive and not as a proposition of the actual GHG emissions from these vehicles. In 

addition, the new regulations address a methodology for compressed natural gas (CNG) vehicles for the 

first time.

Overall, my recommendation to the SAB would be that there is not a major new scientific issue 

associated with these regulations, and it should not be a high priority for action on our part.

Jerry Schnoor, SAB Member
11

Attachment D. SAB Evaluation Criteria

Because time and resources are always limited, the Science Advisory Board uses criteria for selection of 

advisory activities. Activities that are best suited for consideration by the SAB are those that meet 

several criteria. The following criteria have been used in the past to select advisory activities that are 

best suited for consideration by the SAB. 

General Criterion

A. Provides an opportunity to make a difference in the science that supports the agency’s 

mission.

Client-Related Criteria

B. Supports major regulatory or risk management initiatives.

C. Serves leadership interests (e.g., the Administrator, the Congress)

D. Supports EPA strategic priorities.

Science Driven Criteria

E. Involves scientific approaches that are new to the agency.

F. Addresses areas of substantial uncertainties.

Problem Driven Criteria

G. Involves major environmental risks.

H. Relates to emerging environmental issues.

I. Exhibits a long-term outlook.

Organizational Criteria

J. Serves as a model for future agency methods.

K. Requires the commitment of substantial resources to scientific or technological development.

L. Transcends organizational boundaries, within or outside EPA (includes international 

boundaries).

M. Strengthens the agency’s basic capabilities.
12

Attachment E. EPA’s Air Toxics Standards for Major and Area Source Boilers and Certain 

Incinerators: Overview of Changes and Impacts.
13
14
15
16

Attachment F. Summary of Fact-Finding Meeting on Scientific and Technical Issues for EPA 

Proposed Rules Relating to HAPs Emission Standards for Boilers and Incinerators

(SAB Staff Office Summary)

Teleconference Date: February 3, 2012 (2:00 - 3:15 p.m. Eastern Time)

Participants:

SAB Members: David Allen and Peter Thorne

SAB Staff Office: Stephanie Sanzone, Angela Nugent

EPA Representatives: Carl Mazza, Robert Wayland, David Cozzie

Welcome: Ms. Sanzone thanked the EPA program representatives for taking time to provide background 

on four proposed rules and answer questions from the Science Advisory Board (SAB) members. 

Explanation of the Process: Ms. Sanzone briefly described the context for the meeting and made the 

following points. In a memorandum from the Associate Administrator for Policy, dated January 19, 

2012, the EPA articulated a process for coordinating with the SAB on upcoming proposed actions. Prior 

to that, the EPA Office of Air and Radiation (OAR) had notified the SAB Staff Office on December 23, 

2011, of a set of proposed rules that had been published in the Federal Register. The SAB is piloting a 

process for evaluating proposed EPA actions to determine for which, if any, the SAB wishes to provide 

advice and comment. The screening process will include applying some general criteria to identify 

which proposed actions would be suitable for SAB comment. Since the SAB does not have a standing 

committee that addresses air quality issues, several SAB members agreed to take the lead to develop an 

initial recommendation to the full SAB regarding the four proposed air rules. This discussion will be one 

of the agenda items for an SAB meeting on March 22-23, 2012.

The SAB is a federal advisory committee, so its deliberations are held in public. However, individual 

members are permitted to conduct fact-finding discussions as needed. Ms. Sanzone noted that her role as 

Designated Federal Officer (DFO) for the meeting is to facilitate that fact-finding and keep a summary 

of the discussions for the record. 

Background on the Proposed Rules: Ms. Sanzone requested that the EPA representatives provide a brief 

overview of the rationale for the proposal to reconsider aspects of the final rules released in 2011, after 

which Drs. Allen and Thorne would ask any technical questions they had about the science underlying 

the proposed rules.

Dr. Wayland, EPA Office of Air and Radiation, gave a brief overview of the Boiler Major Source 

proposed rule, noting that the agency had been under a tight schedule to finalize the original rules and 

had decided to provide an additional opportunity for public comment. The final rules were issued in 

March 2011, with concurrent notice of the agency’s intent to reconsider certain provisions of the rules. 

In May 2011 the agency issued a stay pending the reconsideration and in December 2011 the agency 

published the proposed rules with a 60-day period for public comment. The proposed revisions to the 

rule are intended to provide maximum flexibility, while maintaining the significant health benefits, in 

response to Congressional and public stakeholder concerns.

He noted some of the changes being proposed, including considering particulate matter (PM) emissions 

associated with various fuels as a function of the combustion process and control systems; adjusted 

carbon monoxide (CO) emission limits based on new data; and a shift to a work practice standard for 
17

dioxins and furans rather than an emission limit because much of the data showed that emissions were at 

or below detection limits for these compounds.

Proposed changes for Area Sources include providing an additional year for area source boilers to meet 

the goal, and changes to the tune-up schedule for units that operate on a seasonal basis.

Mr. Cozzie, EPA Office of Air and Radiation, gave a brief introduction to the proposed Commercial and 

Industrial Solid Waste Incinerator (CISWI) rule, noting that the agency had similar reasons for the 

reconsideration of the rule as with the boiler rules (i.e., the short time between proposal and final rule). 

The agency is required to set numerical standards for nine pollutants listed in the Clean Air Act (CAA). 

The CISWI applies to nonhazardous wastes burned in an incinerator so the definition of hazardous waste 

is important. The non-hazardous secondary material (NHSM) rule defines the types of wastes that can be 

treated as fuels thereby determining whether they are subject to the boiler rule or the CISWI rule. He 

noted that the revisions to the rule were based on additional data and information.

SAB Member Questions and Answers: Dr. Allen noted that the current SAB fact-finding is part of its 

response to the Environmental Research Development and Demonstration Authorization Act 

(ERDDAA) of 1978, whereby the SAB has an opportunity to provide advice and comment on the 

adequacy of the science supporting proposed agency actions. To fulfill that role, the SAB needs to 

identify whether there are science issues associated with the proposed rules that should be considered by 

the SAB. Dr. Thorne also noted that this exercise is consistent with the SAB’s mission to serve the 

public by bringing forth the best science. The following is a summary of questions posed by the 

members, and answers provided by agency representatives.

Q. Regarding the proposal to replace numeric dioxin emission limits with work practice standards, how 

will the agency balance consideration of public health risks at low levels of dioxin emissions with the 

limitations of detection methods? Would required sampling times be too long and costs too high, or are 

methods just not available?

A. The EPA approaches to hazardous air pollutant (HAP) regulation (e.g., 3-hour samples) cannot 

accurately and reliably measure dioxins and furans at the levels emitted from these sources. Also, there 

is no control technology available other than to reduce the fuel use, so that is why the focus is on 

ensuring that tune-ups assure best combustion conditions. More than 80 percent of dioxin emission 

measurements were below three times the detection limit. Many public comments raised this issue, and 

the agency agreed. 

Q. For the flame to produce dioxins, there needs to be a source of chlorine. What is the source (i.e., the 

air, the fuel)?

A. Small amounts of chlorine are in natural fuels, although some coals or biomass have more chlorine 

than others. The tune-up of the boiler provides the most efficient flame zone ensuring the most efficient 

destruction of these compounds. 

Q. How does the proposal for work practices relate to the enforcement provisions of the CAA?

A. CAA section 112(h) says that if it is technologically and economically infeasible to monitor a 

pollutant, EPA can issue a work practice standard. In the proposed rule, the agency makes the case that 
18

both are true for dioxins/furans (i.e., there is not a consistently reliable test method at that level, and a 

requirement to sample over multiple days would be too costly). 

Q. Is there evidence not based on dioxin emission measurements that a tuned-up boiler produces less 

dioxin? 

A. This approach is consistent with engineering practice logic used by EPA for other pollutants 

(greenhouse gases, etc). The collection of considerations was used to support the approach. Also, the 

quantified benefits are associated mostly with reductions in primary PM and SO2. Other HAPs don’t 

have epidemiology studies that can be used to quantify the benefits.

Q. Will combustion characteristics change as a result of the tune-ups? e.g., if a tune-up increases the 

flame temperature, that can increase NOx formation. Is there something similar for dioxins? 

A. No, in fact boilers are used to destroy chlorine-rich waste streams. If conditions push CO too low, 

that might increase NOx, so the goal is to minimize both. There are lots of data for those two pollutants. 

However, for dioxins, furans, PCBs, etc., there are not continuous emission monitoring data. 

Q. If anticipated risks are at levels lower than analytical methods can detect, how does the agency decide 

to evaluate or develop alternative methods?

A. EPA engineers coordinate with the EPA monitoring personnel with regard to monitoring methods 

and capabilities. In addition, the Office of Research and Development (ORD) works to refine test 

methods and instrumentation, works with instrument manufacturers, etc. For the 1990 CAA 

Amendments, municipal waste combustors were the largest sources of dioxins and existing techniques 

worked well for assessing those levels. However, the industrial units covered under the current proposed 

rule are not burning high-chlorine fuels so the dioxin emissions are many orders of magnitude lower 

than the levels for which EPA had been using the test method. Sulfur actually inhibits dioxin formation, 

so that is a factor when burning coal. For these reasons, the agency is proposing to set a work practice 

standard and continue to work with ORD, etc. 

Q. When the SAB talks to ORD about research strategies, what is the message on the need to develop a 

new federal reference method? In other words, how much residual risk is associated with these dioxin 

emissions and what priority is needed for new methods development? 

A. The ORD expert on dioxin has worked with OAR on both of these rules, so he is aware of the issue. 

One consideration is that only a half dozen laboratories in the U.S. are eligible to run these tests, and 

only one or two of those are reliable and reputable. In contrast, PM analysis is easy to get. So, regulation 

requires all three: a reliable test method; engineering that goes with it; and private sector testing 

expertise.

Q. Pick an example of a waste (e.g., tires, treated lumber) and explain the implications of the proposed 

NHSM rule.

A. Detailed discussion of that rule should come from the Office of Solid Waste. In brief, however, the 

NHSM defines what is a waste versus what is a potential fuel thereby determining which emission 

standards apply. The proposed rule clarifies the legitimacy criteria for being considered a fuel, such as 

BTU value and comparability with other fuels.
19

Q. The proposed rule sets PM emissions limits for different fuel categories. How will that be 

operationalized? 

A. The final March 2011 rule considered Hg and HCl as fuel-based pollutants, vs. dioxins and furans 

which are a function of the type of combustor. PM emissions profiles are more related to combustor type 

than fuel type. Therefore, instead of a single PM limit for solid vs. liquid vs. gas fuels, the proposed rule 

sets limits that are combustor-specific. CAA section 112 gives broad discretion to set subcategories 

where class, size or type differences exist. For PM, there are differences in particle sizes, efficiency of 

downstream control devices, and the ways these emissions can be measured for different types of 

combustors. The data supported the conclusion that PM emissions primarily are combustion-related, 

rather than fuel-related.

Q. Does PM from each of the 16 subcategories have different toxicities? 

A. CAA section 112(d) is a technology-driven program, whereas section 112(f) is the residual risk 

program. Section 112(d) requires establishment of broad national regulations that provide maximum 

achievable control technology (MACT), so the agency identifies the best available control that can 

reduce emissions. Under Section 112(f), EPA will look at risks from every remaining source to see if 

residual risks are reduced to the 1 in a million criterion. If not, EPA is to use a risk-based approach to 

look at the issue. EPA cannot do both steps at once because of the way the statute is written. (Residual 

risk assessment happens within eight years of setting the MACT.)

Q. If the data show that different processes have different efficacies, is there a way to phase out the less 

desirable processes? 

A. Under section 112, EPA sets a numerical limit (based on the best-performing 12 percent of facilities) 

but doesn’t specify how to comply. For example, if a unit is burning biomass and can’t meet the 

emission limit, it could switch to natural gas, etc. Some units choose to retire because of the costs to 

comply in comparison to the utility of the facility. Or, facilities may change from a wet to a dry process, 

etc. 
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Attachment G. Science Topics Raised by Commenters at Public Hearings for Light-Duty 2017-

2025 Greenhouse Gas and CAFE Standards Notice of Proposed Rulemaking 

(EPA Staff Summary, February 17, 2012)

This document was prepared in response to a request from Stephanie Sanzone, Designated Federal 

Officer for the EPA Science Advisory Board, for a summary of the science related comments provided 

by commenter’s at the recently held public hearing for the Joint Notice of Proposed Rulemaking for 

Model Year 2017-2025 light-duty vehicle greenhouse gas and CAFE standards.

- EPA & the National Highway Traffic Safety Administration (NHTSA) held 3 public hearings in 

January 2012 regarding the Joint Notice of Proposed Rulemaking for Model Years 2017-2025 

light-duty vehicle GHG and CAFE standards.

- Several hundred individual’s provided oral testimony regarding the proposed 2017-2025 

standards, including private citizens, representatives from individual companies and trade

associations, labor unions, elected officials at the local, state and federal level, and a range of 

non-governmental organizations.

- This document is a brief listing of the comments received at the public hearing related to 

scientific issues. It should be noted that commenters were asked to keep their testimony to no 

more than 5 or 10 minutes. Given that time constraint, EPA staff believe it is very likely that 

many stakeholders will cover a wider range of topics, and in more detail, in their written 

comments then they were able to cover in testimony at the public hearings. Our initial review of 

the comments which have been submitted to the public docket for this rulemaking is confirming 

this view.

Vehicle life cycle modeling (not including fuels) – the American Iron and Steel Institute (AISI) 

commented that while the NPRM proposed primarily vehicle tailpipe emission standards, for the 

mid-term review, EPA and NHTSA should consider life cycle GHG emission standards which 

taken into account the production related emissions of all components which go into a vehicle. 

AISI was silent on the topic of the inclusion of life cycle emissions for vehicle fuels – their 

comments focused on the production of the vehicle. AISI cited studies from UC Santa Barbara, 

UC Davis, and the University of Michigan to support their recommendations. Comments on this 

topic were also made by U.S. Steel.

- Upstream emissions from electric vehicles – in the Joint NPRM, EPA proposed both a 

methodology to account for upstream GHG emissions from electric vehicles (and the electric 

drive portion of driving for plug-in hybrid electric vehicles), as well as a specific time frame and 

sales volume threshold which would trigger an individual auto companies requirements to begin 

accounting for upstream emissions for electric vehicles. During the public hearings, several 

commenter’s discussed the policy implications of EPA’s proposal, however, no comments were 

made on the specific accounting methodology proposed by EPA. The policy-related 

commenter’s included General Motors Corporation, Nissan, Honda Motor Company, the 

Northeast States for Coordinated Air Use Management, BMW, and a large number of 

environmental non-governmental organizations.
21

- Off-cycle emission credit opportunities for additional technologies- several companies, including 

SABIC, Bayer Material Science, and the American Chemistry Council, commented that EPA 

and NHTSA should consider the potential environmental benefits of using polycarbonate glazing 

coatings for windows which can reduce thermal loading on a vehicle and thus reduce the need 

for air conditioning use in a vehicle. Companies cited a number of specific properties or 

characteristics of polycarbonate materials which they said would result in environmental 

benefits.

- Climate change - while this specific Notice of Proposed Rulemaking does not include any new 

analysis regarding the science of climate change (this Joint NPRM proposes new greenhouse gas 

standards from EPA and CAFE standards from NHTSA), many commenters discuss the types of 

climate impacts which they believe could be partially mitigated as a result of the proposed 

standards, and in some cases cited specific literature or provided copies of articles from the 

literature to supplement their comments. The number of commenters with this view was very 

large, and includes many private citizens, as well as a large number of non-governmental 

organizations, including but not limited to the Natural Resources Defense Council, the Center for 

Biological Diversity, the Sierra Club, Union of Concerned Scientists, World Wildlife Federation, 

Environment America, Environmental Defense Fund, and the International Council for Clean 

Transportation.
22

Attachment H. Peer Reviewed EPA Studies Utilized in the Light-Duty 2017-2025 Greenhouse Gas 

and CAFE Standards Notice of Proposed Rulemaking (EPA Staff Summary)

The following is the list of key technical reports and models which were funded by EPA and utilized in 

the 2017-2025 light-duty vehicles NPRM. Note this is by no means the complete list of peer reviewed 

work relied upon by EPA and NHTSA for the Joint NPRM. Rather, this is a list of the important studies 

and models utilized by EPA in the Joint NPRM where EPA either performed the work or EPA 

commissioned the work – that is, EPA paid for the study or model.

“A Study of Potential Effectiveness of Carbon Dioxide Reducing Vehicle Technologies – Revised Final 

Report”, EPA Report 420-R-08-004a, June 2008

“Peer Review for the PQA/Ricardo Report ‘A Study of Potential Effectiveness of Carbon Dioxide 

Reducing Vehicle Technologies”, EPA Report 420-S-08-002, January 2008

“Automobile Industry Retail Price Equivalent and Indirect Cost Multipliers”, RTI International/U. of 

Michigan, EPA Report 420-R-09-003, Feb. 2009

“Peer Review for the RTI Report, Automobile Industry Retail Price Equivalent and Indirect Cost 

Multipliers”, EPA Report 420-R-004, June 2009

“Using indirect cost multipliers to estimate the total cost of adding new technology in the automobile 

industry”, International Journal of Production Economics, April 2010

“Light-Duty Technology Cost Analysis Pilot Study”, EPA Report 420-R-09-020, Dec. 2009

“Peer Review of Light-duty Technology Cost Analysis Pilot Study”, ICF International, Nov. 2009

“Response to Comments of Light-duty Technology Cost Analysis Pilot Study” EPA/FEV, EPA Report 

420-R-09-021

“OMEGA Model Documentation”, EPA Report 420-B-10-042 

Peer Review of OMEGA and EPA’s Response to Comments, EPA Report 420-R-09-016, Sept. 2009

FEV, Inc., “Light-Duty Technology Cost Analysis, Power-Split and P2 HEV Case Studies”, Contract 

No. EP-C-07-069, Work Assignment 3-3, EPA Report EPA-420-R-11-015, November 2011. 

ICF, “Peer Review of FEV Inc. Report “Light Duty Technology Cost Analysis, Power-Split

and P2 Hybrid Electric Vehicle Case Studies”, EPA Report EPA-420-R-11-016, November 2011. 

FEV, Inc. and U.S. EPA, “FEV Inc. Report ‘Light Duty Technology Cost Analysis, PowerSplit and P2 Hybrid Electric Vehicle Case Studies’, Peer Review Report – Response to Comments 

Document”, EPA Report EPA-420-R-11-017, November 2011. 

Ricardo Inc., “Project Report Computer Simulation of Light-duty Vehicle Technologies for

Greenhouse Gas Emission Reduction in the 2020–2025 Timeframe,” 2011, Contract No. EPC11-007, Work Assignment 0-12, November, 2011. EPA Report EPA-420-R-11-020
23

Systems Research and Applications Corporation (SRA), “Response to Peer

Review of: Ricardo, Inc. Draft Report, ‘Computer Simulation of Light-Duty Vehicle

Technologies for Greenhouse Gas Emission Reduction in the 2020-2025 Timeframe’” EPA

Contract No. EP-C-11-007, Work Assignment 0-12, November, 2011. EPA Report EPA-420-R-11-21

"How Consumers Value Fuel Economy: A Literature Review," by David Greene, Oak Ridge National 

Laboratory, EPA Report EPA-420-R-10-008, March 2010

"Peer Review for the Report, 'How Consumers Value Fuel Economy: A Literature Review,'" EPA 

Report EPA-420-S-10-001

“Evaluating the Consumer Response to Fuel Economy: A Review of the Literature.”, Gloria Helfand 

and Ann Wolverton of EPA, published in International Review of Environmental and Resource 

Economics 5 (2011): 103-146