**Cleveland Cliffs, Inc.**

**Comments on the Proposed**

**National Emission Standard for**

**Hazardous Air Pollutants for**

**Taconite Ore Processing**

**As Published in the Federal Register**

**on December 18, 2002**

**67 Fed. Reg. 77562**

**Submitted: February 18, 2003**

**TABLE OF CONTENTS**

[I. Introduction 4](#i.-introduction)

[II. Comments on the Preamble & specific rule language
5](#ii.-comments-on-the-preamble-specific-rule-language)

[A. Background Discussion on the Proposed Rule
5](#a.-background-discussion-on-the-proposed-rule)

[1. Taconite Iron Ore Processing Should be Split into Two Source
Categories
5](#taconite-iron-ore-processing-should-be-split-into-two-source-categories)

[2. The Material Handling Operations Should Not be Subject to NESHAP
5](#the-material-handling-operations-should-not-be-subject-to-neshap)

[3. The Preamble Contains Some Mischaracterizations
6](#the-preamble-contains-some-mischaracterizations)

[4. General Inaccuracies in the Preamble or Rule
7](#general-inaccuracies-in-the-preamble-or-rule)

[5. Not all Fluxuations in Operation Constitute Deviations
7](#not-all-fluxuations-in-operation-constitute-deviations)

[B. EPA's Summary of the Proposed Rule & Stated Rationale for the
Proposed Standard
8](#b.-epas-summary-of-the-proposed-rule-stated-rationale-for-the-proposed-standard)

[1. Definition of Affected Source 8](#definition-of-affected-source)

[a. Definition of Finished Pellet Handling Should be Clarified
9](#a.-definition-of-finished-pellet-handling-should-be-clarified)

[b. Definition of Vents Should be Clarified
9](#b.-definition-of-vents-should-be-clarified)

[2. Emission Limits and Work Practice Standards
10](#emission-limits-and-work-practice-standards)

[3. Development of the NESHAP Floors
10](#development-of-the-neshap-floors)

[4. Operation and Maintenance Requirements
11](#operation-and-maintenance-requirements)

[5. Initial Compliance Requirements
11](#initial-compliance-requirements)

[6. Continuous Compliance Requirements
13](#continuous-compliance-requirements)

[a. Bag Leak Detection Systems 13](#a.-bag-leak-detection-systems)

[b. Wet Scrubbers 15](#b.-wet-scrubbers)

[c. Continuous Opacity Monitors 16](#c.-continuous-opacity-monitors)

[d. Calibration Checks 17](#d.-calibration-checks)

[e. Pluggage Checks and Electrical Continuity Checks
18](#e.-pluggage-checks-and-electrical-continuity-checks)

[7. Notification, Recordkeeping, and Reporting Requirements
18](#notification-recordkeeping-and-reporting-requirements)

[III. General Comments 19](#iii.-general-comments)

[A. Section 112 Explicitly Provides For A Risk Based Approach To
Regulating HAPs
19](#a.-section-112-explicitly-provides-for-a-risk-based-approach-to-regulating-haps)

[1. Summary of Legal Framework for Regulating HAPs Under the CAA
20](#summary-of-legal-framework-for-regulating-haps-under-the-caa)

[2. Detailed Analysis of Legal Framework of Section 112 for Regulating
HAPs
21](#detailed-analysis-of-legal-framework-of-section-112-for-regulating-haps)

[**a.** **Section 112(b) -- List of HAPs**
21](#__RefHeading___Toc33352029)

[**b.** **Section 112(c) -- List of Source Categories**
22](#__RefHeading___Toc33352030)

[**c.** **Section 112(d) -- Emission Standards**
22](#__RefHeading___Toc33352031)

[**d.** **Section 112(f) -- Standard to Protect Health and Environment**
24](#__RefHeading___Toc33352032)

[***3.*** ***Miscellaneous Provisions of Section 112 for Regulating
HAPs*** 25](#__RefHeading___Toc33352033)

[***4.*** ***Section 112 of the CAA allows EPA Considerable Discretion
as to How to Regulate HAPs*** 26](#__RefHeading___Toc33352034)

[B. EPA Has the Authority to Implement and Utilize a Risk-Based Approach
to Section 112 of the CAA
26](#b.-epa-has-the-authority-to-implement-and-utilize-a-risk-based-approach-to-section-112-of-the-caa)

[1. Summary of Legal Framework for Utilizing a Risk Based Approach to
Regulating HAPs Under the CAA
27](#summary-of-legal-framework-for-utilizing-a-risk-based-approach-to-regulating-haps-under-the-caa)

[a. Potential Risk-Based Approaches to Regulating HAPs
28](#a.-potential-risk-based-approaches-to-regulating-haps)

[1. Applicability Cutoff for Threshold Pollutants Under Section
112(d)(4)
29](#applicability-cutoff-for-threshold-pollutants-under-section-112d4)

[2. Hazard Quotients and Indices 31](#hazard-quotients-and-indices)

[3. Tiered analytical approach for predicting exposure.
32](#tiered-analytical-approach-for-predicting-exposure.)

[4. Accounting for dose-response relationships.
33](#accounting-for-dose-response-relationships.)

[5. Risk assessment results 34](#risk-assessment-results)

[b. Subcategory Delisting Under Section 112(c)(9)(B) of the CAA
35](#b.-subcategory-delisting-under-section-112c9b-of-the-caa)

[c. Acceptable Levels of Risk 36](#c.-acceptable-levels-of-risk)

[C. EPA Has General Authority To Exempt *De Minimis* Emissions Based on
Concentration or Risk
38](#c.-epa-has-general-authority-to-exempt-de-minimis-emissions-based-on-concentration-or-risk)

[1. EPA's General De Minimis Authority
38](#epas-general-de-minimis-authority)

[a. EPA Has Authority to Exempt Emissions Which are "Trivial or of No
Value" to the Protection of Public Health or the Environment
39](#a.-epa-has-authority-to-exempt-emissions-which-are-trivial-or-of-no-value-to-the-protection-of-public-health-or-the-environment)

[b. EPA Has Wrongfully Attempted to Deny this De Minimis Authority
40](#b.-epa-has-wrongfully-attempted-to-deny-this-de-minimis-authority)

[2. Risk-Based Approach to De Minimis
40](#risk-based-approach-to-de-minimis)

[a. The Statute Provides Both Implicit and Explicit De Minimis Authority
41](#__RefHeading___Toc33352050)

[b. The Caselaw Supports EPA's De Minimis Authority
42](#b.-the-caselaw-supports-epas-de-minimis-authority)

[3. Concentration or Quantity-Based Approach to De Minimis
43](#concentration-or-quantity-based-approach-to-de-minimis)

[4. Practical Application of EPA's Health Risk-Based De Minimis
Authority
43](#practical-application-of-epas-health-risk-based-de-minimis-authority)

[D. Economic and Cost Issues 44](#d.-economic-and-cost-issues)

[1. EPA's own Analysis indicates that this Rule will Have Dire Economic
Impacts on the Taconite Iron Ore Processing Industry
44](#epas-own-analysis-indicates-that-this-rule-will-have-dire-economic-impacts-on-the-taconite-iron-ore-processing-industry)

[2. EPA's Economic Analysis Understates the Economic Impact of the
Rulemaking and is Riddled with Errors
44](#epas-economic-analysis-understates-the-economic-impact-of-the-rulemaking-and-is-riddled-with-errors)

[a. Executive Summary of the EIA 44](#a.-executive-summary-of-the-eia)

[b. Inaccuracies in the Introduction to the EIA
45](#b.-inaccuracies-in-the-introduction-to-the-eia)

[c. Industry Profile as Characterized by the EIA
45](#c.-industry-profile-as-characterized-by-the-eia)

[d. Summary of Costs According to the EIA
45](#d.-summary-of-costs-according-to-the-eia)

[e. Economic Impact Analysis 46](#e.-economic-impact-analysis)

[E. Background Information on the Taconite Iron Ore Processing Industry
47](#e.-background-information-on-the-taconite-iron-ore-processing-industry)

[[IV.]{.smallcaps} [R]{.smallcaps}ecommendations
47](#iv.-recommendations)

[A. Split the Taconite Ore Processing Category into Two Source
Categories
47](#a.-split-the-taconite-ore-processing-category-into-two-source-categories)

[B. EPA Should Carefully Review and then Grant the Delisting Petition
49](#b.-epa-should-carefully-review-and-then-grant-the-delisting-petition)

[C. Include Alternative Risk-Based or De Minimis Approaches for this
NESHAP
49](#c.-include-alternative-risk-based-or-de-minimis-approaches-for-this-neshap)

[V. CONCLUSION 50](#v.-conclusion)

**Comments on the Proposed National Emission Standard for**

**Hazardous Air Pollutants for Taconite Ore Processing**

**67 Fed. Reg. 77562, December 18, 2002**

**Submitted by the Cleveland Cliffs, Inc.**

**February 18, 2003**

# I. Introduction

These comments have been submitted on behalf of the Cleveland Cliffs,
Inc ("CCI"). CCI owns or operates, in full or in part, four (4) Taconite
Iron Ore Processing ("TIOP") operations in the United States. Two of
these operations are in Northern Minnesota Northshore Mining Company and
Hibbing Taconite Company) and two are located in Michigan's Upper
Michigan (Empire Iron Mining Partnership and Tilden Mining Company).

CCI has tremendous concern with the proposed NESHAP for Taconite Iron
Ore Processing. Based on our analyses, the cost of this rulemaking is
greatly disproportionate to the resulting reduction of Hazardous Air
Pollutants ("HAPs"). In fact, our preliminary studies indicate that the
entire TIOP source category should be de-listed in accordance with
Section 112(c)(9) of the Clean Air Act ("CAA")[^1]. CCI is participating
in an effort to prepare a de-listing petition for TIOP operations under
Section 112(c)(9). We anticipate submitting this petition by June 30,
2003.

In the interim, the TIOP source category should be split into two source
categories which more accurately reflect the two diverse types of
operations found at taconite iron ore processing operations: thermal
indurating furnace operations, and physical material handling
operations. Splitting this source category into two source categories is
well within EPA's discretion and is consistent both with the clear
language of the Clean Air Act ("CAA") and the intent of Congress.
Moreover, splitting the original source category into two categories is
consistent with EPA's concept of defining and regulating the "affected
sources" at TIOP operations. This approach would be consistent with the
proposed NESHAP for Brick and Structural Clay and Ceramic Clay products
(67 Fed. Reg. 47894, July 22, 2002) and the proposed decision not to
develop a NESHAP to regulate Chlorine and Hydrochloric Acid Emissions
from Chlorine Production (67 Fed. Reg. 44713, July 3, 2002).

In the event the delisting petition is delayed or denied for some
reason, we are also submitting detailed comments on provisions in the
proposed rule, and, comments on provisions that were not addressed or
included in the proposed rule, but that should be addressed in any final
rule regulating this source category.

Thus, the second section of these comments addresses what has been
presented in the proposed rule (preamble and proposed CFR language) and
then goes on to make recommendations for major changes in the manner in
which this source category is proposed to be regulated. For your
convenience, in addition to this narrative discussion in Section II, we
have also attached a redlined version of the language of the rule
reflected our specific suggestions.

Section III of these comments contains our general comments on issues
regarding the rulemaking. Many of these issues were not addressed in
either the preamble or the rule itself, such as splitting the source
category and many of the risk based approaches which should be
considered and adopted for TIOP operations. Finally, Section IV contains
our recommendations for how to proceed with handling this source
category.

# II. Comments on the Preamble & specific rule language

## A. Background Discussion on the Proposed Rule

### 1. Taconite Iron Ore Processing Should be Split into Two Source Categories

Section I.C. of the preamble describes the source category for the
proposed Taconite Iron Ore Processing ("TIOP") NESHAP. As discussed in
our comments below (Section IV, Recommendations), this source category
should be split into two source categories. One for the material
handling operations and the other for the indurating furnaces. The first
category should cover material handling operations for Taconite Ore
Processing and would consist of the ore crushing and handling units, ore
dryers, and finished pellet handling units located at the processing
facility. The second category would consist of the indurating furnaces
located at the processing facility. This latter category would then be
subcategorized into straight grate furnaces and grate kiln furnaces.
This subcategorization of the furnace operations is consistent with the
current proposal. (67 Fed. Reg. 77562,77570, December 18, 2002.) This is
also consistent with the form of the proposed rule, i.e., the manner in
which the rule is split into several different affected sources with
associated emission limitations.

Congress granted EPA great discretion in establishing source categories.
Splitting the category is clearly within the discretion of the Agency
and is appropriate in this case since the current category addresses two
very separate types of operations (material handling and indurating
furnaces). These two types of operations are sufficiently different and
distinct from each other to warrant revising the source category list.
Further explanation and support for this concept is discussed in Section
V of these comments.

### 2. The Material Handling Operations Should Not be Subject to NESHAP

According to EPA's own Background Information Document ("BID") for
Taconite Iron Ore Processing, the total metallic HAP emissions from
material handling operations is 8.66 tons per year.[^2] Approximately 98
percent of this is Manganese (\~ 8.45 tons per year) and the remaining
two percent accounts for all the other metallic HAPs. EPA estimates that
all of these other metallic HAPs are emitted at levels less than 130
pounds per year.[^3]

Recent data confirms that no individual facility has material handling
operations which have the potential to emit more than 10 tons per year
of any individual HAP, nor 25 tons per year of any combination of HAP.
Therefore, after splitting the material handling operations into a
source category separate from the furnace operations, the material
handling source category can be "delisted" because none of the
operations are, in and of themselves, major sources of HAP. This
approach is consistent with EPA's action in the July 3, 2002, federal
register notice announcing the Agency's proposed decision not to
regulate chlor-alkali plants.[^4] Also, as with the chlorine production
source category, there are a very limited number of facilities that fit
under the source category, i.e., 8 remaining taconite iron ore
processing operations in the United States.

In short, once split off, the material handling operations associated
with the Taconite Iron Ore processing NESHAP should be delisted since
none of the operations are a major source. Alternatively, EPA could also
adopt risk based provisions such as those proposed in various recent
NESHAP rulemakings and delist these operations based on Section
112(c)(9) of the CAA or Section 112(d)(4).[^5] [^6]

### 3. The Preamble Contains Some Mischaracterizations

Section I.D. describes the taconite mining process as "strip mining".
Actually, it is an "open pit" mining process. Section I.F. of the
preamble discusses the health effects associated with emissions from
Taconite Ore Processing Plants. We are concerned that the health effect
characterizations are stated so strongly that a member of the public
could misinterpret this section to state that such health effects will
occur with certainty to those populations around Taconite Iron Ore
Processing facilities. Instead, the health and environmental effects
noted in the preamble are specifically associated with certain exposures
(both in terms of frequency, duration, and quantity) to the listed
chemicals and compounds. Just because those compounds may be emitted in
some quantity from Taconite Iron Ore Processing facilities does not mean
that they are emitted in such a quantity, duration, and frequency that
would impact public health or the environment. We believe EPA
understands this principle, but again are concerned that members of the
public may become unnecessarily alarmed by reading the preamble and
misinterpreting it to state that such effects will occur. Instead, as
stated by the medieval alchemist, Paracelsus, generally regarded as the
"father of toxicology": "All substances are poisons; there is none that
is not a poison. The right dose differentiates a poison from a remedy."
Paracelsus (1493 -- 1541). This is particularly relevant since many of
the heavy metal compounds noted as pollutants are also noted as
nutritionally essential in humans.

### 4. General Inaccuracies in the Preamble or Rule

Subtitle E of Section I details the HAP emitted and the method of
control. The numbers given in the section need to be updated to
accurately reflect what is currently being emitted. U.S. Steel has
testing data that can replace the estimates. A more accurate depiction
of the emission will alter the economic analysis.

The air emission impacts stated on page 93 make assumptions that are not
definite. The rule is an emission based standard not a technology based
standard. The emissions being proposed to control are the ones that
should be reflected in the analysis. Depending on the final choice of
control technology for each individual source, the reduction in the HAP
emissions may be very minor. The EPA should adjust their calculations to
reflect the HAPs being controlled by this standard.

The cost impacts of \$47.3 million are not accurate. As discussed in
detail below in the section critiquing the EPA's Economic Impact
Analysis, the cost to the industry was grossly underestimated and
assumptions made do not reflect the current economic situation of the
country nor industry.

There is confusing language regarding the use and contents of a fugitive
emissions plan and an operation and maintenance plan (O&M Plan). Page
77567 mentions fugitive emission plans having control device procedures
and listing operating limits. The affected sources are already required
to have an O&M and fugitive plans per Title V requirements. All
provisions related to fugitive dust should be deleted so as to avoid
duplication and potentially even conflicts with existing Title V
permits.

The proposed rule requires compliance testing be completed within 2
years following the compliance date. Language either authorizing some
discretion on behalf of state agencies or otherwise allowing testing
completed between the promulgation date and compliance date to be
counted as initial compliance testing, should be added. This allows the
affected companies additional time to spread out the compliance testing
requirements. Also testing frequency should mimic Title V requirements.

### 5. Not all Fluxuations in Operation Constitute Deviations

Not all variations in operation constitute "deviations". All mechanical
and electrical equipment operates within a range of what would
constitute "proper operation". As long as a source is operating
properly, variations within the range of proper operation should not
constitute deviations. This reinforces our objection to using a
performance test to take a snapshot of an operation at a point in time
and then having the Agency assert that that snapshot alone set site
specific operating limits and that operating outside that range would
constitute a deviation. That is not only technically improper and
incorrect, but it is legally incorrect as well. The D.C. Circuit has
made it clear that the MACT standard is to represent the operations of
the best performing source on its worse day.[^7]

For example, if an alarm goes off and you follow procedures in your plan
and proceed appropriately to corrective action, then there shouldn't be
a requirement to report a deviation (unless there was truly an excess
emission). There may be a requirement to log such information and even
report it to the agency, but not necessarily as a deviation under Title
V.

## B. EPA's Summary of the Proposed Rule & Stated Rationale for the Proposed Standard

### 1. Definition of Affected Source

Section II.A. of the preamble describes which emission points are
considered an "affected source". With respect to the descriptions of the
"affected sources" within the current source category, we concur that it
is appropriate to define all the ore crushing and handling emission
units located at the processing facility into an affected source.
However, as with the Portland Cement NESHAP, primary and secondary ore
crushing operations should be explicitly exempt from this
rulemaking.[^8]

Similarly, it is appropriate to define all the finished pellet handling
emission units into an affected source. However, instead of having each
individual furnace be an individual affected source, we believe the
furnace operations should be defined as the affected source. This would
allow companies to average emissions from across the furnace operations
in order to meet the emission limitation. As a result, companies would
have greater flexibility in determining what control strategy to use to
reduce HAP emissions to the appropriate level in the most cost effective
manner. For example, it may be more cost effective to over-control one
furnace while maintaining another in its current status provided that on
average the emissions limitation is met. The environment cannot
recognize or distinguish between which furnace an emission comes from,
and a HAP reduction is a HAP reduction. The rule should allow the
flexibility to achieve the reductions in the most cost effective means
possible.

Section II.A. goes on to discuss the emission limits associated with
each affected source. The preamble clearly describes the affected
sources and how the emissions should be calculated as a flow-weighted
mean concentration for the material handling operations. This concept is
not clear however in the language of the rule itself. We have
incorporated some suggested language changes in the attached redlined
version of the rule. The redlined version is intended to more accurately
reflect the intent of the rule.

Section III.A. discusses the affected sources. We agree with the
definition of the "affected sources" with the exception of defining each
individual furnace as an individual affected source. We believe the
affected source for indurating furnaces should cover all the furnaces at
that location. (Also, as discussed above, the source category itself
should be split so that one source category addresses the material
handling operations and the other addresses the furnace operations.
Consistent with the proposed rule, the affected source for the
indurating furnaces should be split into two subcategories.)

#### a. Definition of Finished Pellet Handling Should be Clarified

In the proposed rule, Section 63.9582 and Section 63.9652 address the
definition of "affected source and finished pellet handling. As drafted,
the proposal can be interpreted to include pellet coolers as a part of
the finished pellet handling affected source. During the development of
Subpart RRRRR, U.S. EPA considered regulating pellet coolers as an
affected source and determined that, due to their emission
characteristics, the regulation of pellet coolers under the taconite
NESHAP was not warranted.

In paragraph D of the background language in the preamble, U.S. EPA
states: "The finished pellet handling process begins where the fired
taconite pellets exit the indurating furnace cooler....." This preamble
language effectively excludes pellet coolers from the finished pellet
handling source category. Similarly in §63.9652, under the definition of
"grate kiln indurating furnace", the proposal states*:* ".....The
atmospheric pellet cooler vent stack is not included as part of the
grate kiln indurating furnace."

Thus the proposed rule language effectively excludes pellet coolers from
the indurating furnace source category. Since the preamble language will
not be included in the final rule language published in the Code of
Federal Regulations, a reader not familiar with the rule development
could incorrectly assume that pellet coolers are a part of the finished
pellet handling source category and are, therefore subject to applicable
emission limitations. We recommend that the rule be amended so that the
Section 63.9652 definition of "finished pellet handling" specifically
excludes the atmospheric pellet cooler vent stack. We have incorporated
suggested language into the attached redlined version of the rule

#### b. Definition of Vents Should be Clarified

Also, with respect to the description of the affected source, Sections
63.9582 and 63.9652 are drafted such that they could be interpreted to
include things like finished pellet conveyor gallery vents and other
vents designed to remove heat and water vapor from the structure as a
part of the affected source.

For example, a finished pellet conveyor gallery structure also typically
includes numerous vents, similar to residential attic vents, designed to
remove heat and water vapor from the structure and are not intended to
provide particulate emission control. These vents are necessary to
prevent equipment corrosion and to reduce gallery temperatures for
worker safety and comfort. The vents are not powered, they depend on
natural draft air which is limited by very low stack heights (max. \~20
ft.). They do not utilize particulate emission control devices and are
not configured in a way that particulate emission testing could be
conducted without extensive modification. The low natural draft implies
an exceedingly low particulate emission rate. Additionally, the natural
draft is subject to variability caused by changes in the weather
conditions including the ambient temperature, wind speed, wind
direction, barometric pressure and by the in-leakage air demands of the
induration process which cause negative pressure conditions in the
entire processing plant structure including the pellet handling areas.

Cleveland Cliffs does not believe that U.S. EPA intended that these
structures be regulated as a part of the finished pellet handling
source, however, such an interpretation is possible with the current
proposed rule language. Section 63.9652 of the rule should be amended so
as to clarify that the definition of "finished pellet handling"
specifically excludes the gravity conveyor gallery vents designed to
remove heat and water vapor from the structure. Again, we have
incorporated suggested language into the attached redlined version of
the rule.

### 2. Emission Limits and Work Practice Standards

Section III.B. of the preamble discusses how the Agency decided to use
particulate matter (PM) as a surrogate for total HAP emissions. We agree
that this is reasonable. Furthermore, it is far more appropriate to use
PM for total metal HAPs than to attempt to speciate individual metal
HAPs. The earthen material that is processed is not necessarily
identical in composition in each and every shovel-full of material. It
would be impossible to account for differences in individual HAP metal
content for each load processed.

### 3. Development of the NESHAP Floors

Section III.C. describes how the EPA established the NESHAP floor for
each affected source. We support the general methodology, but remind the
Agency that the emission limits are to reflect the worst day of the best
performing source.[^9] Thus, there must be allowances in the emission
limitations to allow for variability in the process. As such, we
strongly believe that the emission limitations should be set at 2
significant figures and not 3 significant figures. We believe that using
3 significant figures not only implies more precision in those numbers
than exists in reality, but that it is also unrealistically stringent
and will not allow for natural variations, even in the best performing
source.

We support EPA's analysis regarding beyond-the-floor options for the
affected sources. We concur that such a floor is not warranted for this
source category based on both the emissions and the cost of controlling
them. The marginal gain in emission reductions would be minimal but the
costs would be extraordinary.

### 4. Operation and Maintenance Requirements

Section II.C. discusses operation and maintenance requirements.
Specifically, the rule requires that companies "implement a written
startup, shutdown, and malfunction ("SSM") plan according to the
requirements of the NESHAP general provisions. Instead of referencing
the general provisions, we suggest simply stating the SSM requirements
in this rule. The general provisions are intended to be "gap-fillers",
i.e., requirements which apply unless the specific rule states
otherwise. In this instance, since the SSM general provisions appear to
be in flux due to litigation over the general provisions, we suggest
specifying the provisions in this rule and not having 40 C.F.R. §
63.6(e) apply. This approach will also avoid conflicts between state
rules for SSM plans, Title V requirements, and the NESHAP. Basically,
the SSM plan requirements need only state that such a plan be prepared
and implemented. Furthermore, that the plan be written and amended as
necessary to address SSM issues. There should not be any requirement to
submit the plans to the state agency for approval, instead simply a
requirement that the plan be "approvable" in the sense that it meets the
state requirements and those currently listed under 63.6

Also, this section of the preamble discusses the requirement under
63.9591(b)(2) to initiate corrective action to determine the cause of an
alarm on the bag leak detection system within 1 hour and to initiate
corrective action to fix the problem within 24 hours.

### 5. Initial Compliance Requirements

We strongly object to the use of performance testing to effectively
establish a case by case NESHAP standard for each individual operation.
The only purpose of performance testing should for determining the
compliance status of the operation. In the proposed rule, sources are
required to establish certain operating limits on control devices

> to ensure that control devices operate properly on a continuing basis.
> All operating limits must be established during a performance test
> that demonstrates compliance with the applicable emission limit.
> During the initial compliance tests, operating limits must be
> established for pressure drop and scrubber water flow rate for all wet
> scrubbers, and opacity (using a COMS) for dry ESP.
>
> (67 Fed. Reg. 77562 at 77567, December 18, 2002)

The proposal then goes on to mandate that semiannual reports include
reports of "deviations" from "operating limits". If a source conducts a
stack test, and during the stack test, the source demonstrates
compliance, then that is the sole purpose of that stack test.
Establishing these "operating limits" based on the operation of the
source during the stack test serves to effectively make the NESHAP floor
more stringent for each source on a case by case basis. For example, if
a source were to easily meet the emission limits set by the NESHAP under
certain operating parameters, the proposal would deem any operation
outside of those very specific parameters to be a "deviation". This is
wholly inappropriate. Again, it effectively sets a new NESHAP emission
limit as the emissions actually emitted during the performance test.

This approach goes far beyond the scope of the provisions in the Clean
Air Act, and even goes beyond the scope of EPA's regulations for
implementing compliance assurance monitoring ("CAM"). (40 C.F.R. Part
64.) As described by the D.C. Circuit Court in the NRDC v. EPA case on
EPA's CAM provisions, the court stated:

> Under CAM, EPA requires that major source owners \"establish \...
> appropriate range(s) \... for the selected indicator(s) such that
> operation within the ranges provides a reasonable assurance of ongoing
> compliance with emission limitations or standards.\" 40 C.F.R. §
> 64.3(a)(2). CAM also imposes an affirmative requirement on each major
> source to bring its emissions within the acceptable range when the
> source falls outside the acceptable range. See 40 C.F.R. § 64.7(d).
> Specifically, the source must \"restore operation of the
> pollutant-specific emissions unit (including the control device and
> associated capture system) to its normal or usual manner of operation
> as expeditiously as practicable\....\" Id. CAM expands upon prior
> emissions monitoring by providing major sources with a mechanism to
> implement self-monitoring and self-checks on compliance.[^10]

Section II.D. allows for grouping similar emission units together for
purposes of conducting initial performance tests by testing a
representative sample of units within the group. We strongly support
this approach, i.e., allowing for the determination of the performance
and compliance status of all of the sources to be determined by a
representative sample. It should be expanded to include testing of
furnaces as well. It would be extremely costly and unnecessary to
conduct tests on each point source.

Also, there is a requirement that for the furnace operations,
simultaneous stack testing of multiple stacks must be conducted. This
would be extremely costly, unpractical, and possibly not even feasible.
For example, for a furnace with 5 stacks, this would require that 5
stack testing teams be retained to conduct the tests. This is
unnecessary and unreasonable. Moreover, the requirement to test each
furnace stack twice in every five year Title V permit term is excessive.
Stack testing should only be required when the operation is modified.

For initial (and continuous) compliance testing, Section 63.63.9621
requires that during testing, "a minimum sample volume of 60 dry
standard cubic feet of gas" be obtained "during each particulate matter
test run." (67 Fed. Reg. xxxxx at 77584, December 18, 2002.) This NESHAP
should not include provisions that are different from already
established EPA test methods. Any specific provisions about sample
volume or sample time should be stricken from the language of the rule.

### 6. Continuous Compliance Requirements

Section II.E. of the preamble discusses a requirement to test the
indurating furnaces at least twice per 5 year Title V Renewable
Operating Permit ("ROP") term. There are 21 furnaces across the industry
and these furnaces have 47 stacks. That means that rule requires 92
stack tests for every 5 years. This could be very costly and excessive,
particularly if there has been no change in the operation of the source.
The Agency has already imposed other extensive parametric monitoring on
the furnaces which should suffice for demonstrating compliance unless
the source undergoes a change or modification that would reasonably be
expected to change the quantity or nature of the emissions.

In developing and evaluating monitoring methods for the General
Provisions to the NESHAP standards, EPA explained in the Background
Information Document that monitoring for each individual standard be
developed while ensuring that "the most cost-effective monitoring
methods that provide the needed data are allowed."[^11] The document
goes on to report that "in some cases, emissions monitoring is not
necessary to ensure that control devices are installed and operated
properly."[^12] Again, in 1994, the proposal for the Secondary Lead
Smelting NESHAP (59 Fed. Reg. 29750 at 29772, June 9, 1994) indicates
that monitoring requirements should be evaluated with respect to
"technical feasibility, cost, ease of implementation and relevance to
its underlying process emission limit or control device. The monitoring
requirements in this proposed rule are extremely costly, burdensome and
unnecessary.

In addition, at a minimum, there should be allowances for downtime and
excursions on monitoring equipment. This equipment is generally
complicated and temperamental. The proposal allows baghouses a 5%
allowance for operating in alarm conditions, but there is no such
equivalent condition for wet scrubbers. Such a provision should be
explicit in the rules. Similarly, a 5% downtime for COMs per semi-annual
reporting period should explicitly be defined in the rule as not
constituting a deviation.

#### a. Bag Leak Detection Systems

The proposal requires the installation and operation of an alarmed
baghouse leak detection system for each baghouse used to meet any
particulate emission limit specified in Table 1 of the proposal. While
the proposal does not require a specific type of baghouse leak detection
system, the installation, operation and maintenance requirements for the
required systems indicate that EPA has only considered systems that work
based on the triboelectric effect. Such systems, when installed, must be
installed, operated and maintained in a manner consistent with EPA\'s
guidance document, \"Fabric Filter Bag Leak Detection Guidance,\"
EPA--454/R--98-015, September 1997. Section 63.9590(b)(1) of the
proposal also specifies that bag leak detection system alarms may not
sound more than 5% of the operating time during any semi-annual
reporting period. There are several major problems associated with the
bag leak detection requirement.

First, EPA has not presented any information or justification to support
the requirement that the leak detection alarm must be triggered more
than 5% of the time. The 5% limitation is arbitrary and without basis.
Moreover, this limitation is unnecessary. Under §63.9590, if the bag
leak detection system is triggered, facilities have the obligation to
\"... initiate corrective action to determine the cause of the alarm
within 1 hour of the alarm, initiate corrective action to correct the
cause of the problem within 24 hours of the alarm, and complete the
corrective action as soon as practicable.\" This obligation serves the
dual purpose of minimizing bag leak alarms and assuring a prompt
response to a bag leak problem irrespective of the percentage of time an
alarm might be sounded. For these reasons, the 5% alarm limitation
should be deleted from the rule.

Second, EPA's guidance document states that, \"...only fabric filters
... with exhaust stacks are covered by this guidance.\" Some sources
listed in Table 1 use positive pressure baghouses, which typically do
not utilize an exhaust stack. The compartments of these types of
baghouses typically discharge into a common plenum, which discharges to
the atmosphere through louvered openings in the plenum. EPA recognized
this problem when promulgating its NESHAP standard for Ferroalloys
Production (40 CFR 63 Subpart XXX) by requiring the use of a bag leak
detection system [only]{.underline} for negative pressure baghouses and
positive pressure baghouses equipped with a stack. This approach is
consistent with the EPA guidance document. At a minimum, §63.9590 should
be revised to specify that bag leak detection systems are required only
for negative pressure baghouses and positive pressure baghouses equipped
with a stack.

If the 5% alarm limitation is retained, another problem with the
proposal is the requirement that the baghouse be operated in such a
manner that the bag leak detection system does not alarm for more than
5% of the \"total operating time\" in any semiannual reporting period.
It is unclear if the \"total operating time\" refers to the operating
time of the affected source (*i.e.*, the blast furnace, sinter plant,
*etc.*) or the time the baghouse is actually evacuating emissions
generated by the affected source. Some baghouses, by design, only
evacuate emissions for a few minutes each hour. Only after careful
reading of several sections of the proposal and review of the BID is it
possible to determine with any confidence that EPA intended that the
requirement refers to the total operating time of the
[affected]{.underline} [source]{.underline}.

In order to avoid confusion in interpreting this requirement, if the 5%
limitation is retained, then §63.9590(b)(1) should be revised to read:

(b)(1) For each negative pressure baghouse and each positive pressure
baghouse equipped with a stack applied to meet any particulate emission
limit in Table 1, you must operate the baghouse such that the bag leak
detection system does not alarm for more than 5 percent of the total
operating time of the affected source in any semiannual reporting
period.

Moreover, the 5% threshold appears to be arbitrary. We suggest a 10%
alarm time to be more realistic for these operations.

Another problem is the procedure for determining the percentage of time
the bag leak detection system alarms in any semiannual period. Section
63.7833(d)(1)(iii) specifies that one hour of alarm time be logged even
if procedures are implemented to determine the cause of the alarm and
take corrective action in less than one hour. This requirement
artificially and unfairly inflates the semiannual percentage of alarm
time and does not provide an incentive for sources to initiate
procedures as quickly as may be possible. In practice, this procedure
could result in a source being in violation of the requirement when the
actual alarm time is, in fact, less than 5%.

Also, in order to provide for accurate accounting of an alarm time
operating limit, the rule should state that the company "Count the
actual amount of time you took to initiate procedures to determine the
cause of the alarm."

#### b. Wet Scrubbers

With respect to the wet scrubber operating limits described in Section
63.9590(b)(2), the proposal requires that all wet scrubbers used to meet
a particulate emission limit in this rule must maintain an average
pressure drop at or above the minimum level established during the
initial performance test. As discussed above in Section II.B.5 of these
comments, we strongly object to using performance testing to establish
case-by-case, site specific NESHAP emission limitations. By setting the
average pressure drop at the minimum level established during the
performance test, the rule effectively uses the performance test to
establish not simply compliance, but monitoring parameters which may
well force the source to operate well below the emission limitation
established in the rule.

Moreover, depending on the equipment, it would be wholly inappropriate
to set a single (pressure drop) point for operating wet scrubbers. For
example, rod deck multiple venturi scrubbers have no provision for the
control of pressure drop via adjustable venturi throats or variable
speed fans. These scrubbers operate within a range of acceptable
pressure drop which is influenced by several parameters such as
scrubbing water flow rate, scrubber water flow distribution, water
temperature, gas temperature and , most importantly, the square of the
process gas flow rate. A scrubber pressure drop observed at one point in
time may not be repeatable at some later hour even though the system
exhibits acceptable particulate control efficiency in both cases.
Circumstances beyond the operator's control such as ambient temperature,
water temperature, variations caused by the computer driven automated
control system, or the permeability of the bed of material in process on
the traveling grate will affect the scrubber pressure drop~~s~~. It may
be impossible to maintain a minimum average pressure drop observed
during a performance test on a continuous basis. The procedures for
changing wet scrubber operating limits in §63.9622(c) in the proposal do
not provide an acceptable solution to this problem because of the long
delays associated with the required notifications, testing and approvals
required.

Again, the purpose of the initial performance test is solely to
determine compliance with the NESHAP floor emission limitations. For
purposes of enhanced monitoring under Part 70, companies must have
operation and maintenance procedures in place in order to certify
compliance with applicable limitations. These operation and maintenance
plans are not fungible. Different operations have different
requirements. Rather than attempt to force a site by site emission
limitation on each source by selecting a snapshot parametric setting,
each source should merely have to develop, or revise their existing,
operation and maintenance plans. These plans generally contain
provisions such as vendor specifications for operation of the equipment,
or site specific indicators of proper operation.

It is important to remember that no company wants to improperly operate
their equipment. Not only can such operation result in violations of
various environmental permits, but it also will likely result in damage
to very expensive equipment and also can result in the manufacture of
product that does not meet the company's quality specifications.
Operating equipment improperly has far more negative economic
implications than those imposed by the civil penalty policy. Clearly,
that is not to say that companies do not care about compliance.
companies are very conscientious and operate as good citizens and good
neighbors in their communities. Environmental compliance as well as
natural resource protection is particularly important to these
operations and the communities in which they are located. The point is
that aside from compliance issues, companies fully intend to properly
operate equipment because damaging the equipment that manufacturers the
product, or diminishing the quality of the product will result in
limited sales, limited profits, and a very limited life of the company.

#### c. Continuous Opacity Monitors

The proposed rule requires installation of Continuous Opacity Monitors
("COMs") on each stack with a dry Electrostatic Precipitator ("ESPs").
(See Sections 63.9622(b), 63.9631(c), and 63.9634(f).). The proposal
goes on to require that during initial and subsequent stack tests the
COMS readings would be correlated to the stack test results in order to
establish an emission limit, or compliance point, based on percent
opacity. Then during operations, particulate emissions from dry ESPs
must be continuously measured by COMS. What EPA fails to acknowledge is
that during normal, compliant operations, opacity will likely be less
than

The actual opacity during compliant operations will be much less than
10% and normally very close to zero. EPA provides no evidence that COMS
can even accurately measure opacity when the actual opacity is less than
10%. Moreover, it is generally known that the accuracy of a COM
decreases as the actual opacity tends toward zero.

This sets up a very precarious situation for a facility since the
proposal requires that an initial performance test be conducted and that
COMS data would be used as a parametric measurement of compliance. Not
only is this objectionable because it uses the performance test to set a
case by case and site by site (and even stack by stack) opacity limit,
but since the opacity will generally be low enough to be outside the
range of error of the test method (the COMs), sources could technically
create a reportable "deviation" merely by operating normally and in
compliance with the actual opacity limit.

Just because a source may have a period of visible emissions or COMs
data over some arbitrary limit does not mean that the source is out of
compliance with a PM emission limit, nor even an opacity restriction.
Thus, there should not be any requirement to install nor operate a
continuous opacity monitor on these operations. Instead, there should
merely be a requirement for a visible emission check. We suggest the
same provisions as are contained in the Portland Cement NESHAP.
Specifically, that NESHAP provides:

> We are amending the requirements of § 63.1350(e)(2) of the final rule
> to conduct follow-up VE tests when VE were observed previously. This
> amendment allows the source to have 2 consecutive calendar days of
> visible emissions prior to having to conduct a follow-up test by
> Method 9 (40 CFR part 60, appendix A). The final rule as promulgated
> requires a Method 9 test be conducted within 24 hours for a particular
> raw or finish mill if VE are observed during the daily test by Method
> 22 (40 CFR part 60, appendix A). We agree with industry that this may
> be overly burdensome since the presence of VE does not necessarily
> indicate whether a source is in violation of the 10 percent opacity
> limit. Further, if VE are observed, corrective action may be taken by
> the source to eliminate the emissions prior to the subsequent Method
> 22 test and, thereby, eliminate the emissions and avoid having to do a
> more costly Method 9 test. (67 Fed. Reg. 16614, April 5, 2002.)

The Portland Cement NESHAP provides that "deviations" can only be
determined to occur if after 2 days of visible emissions, a certified
visible emission reader determines that the opacity were in excess of
the applicable opacity limit. Similar provisions for opacity should be
incorporated into this rulemaking.

#### d. Calibration Checks

Section 63.9632(b)(1)(iv) requires monthly transducer and quarterly
gauge calibration checks. Similarly, Section 63.9632(b)(2)(iii) requires
semiannual flow sensor calibration checks. These can be very costly and
the rule should be more flexible so as to allow for alternative methods
of assuring compliance. These provisions require extensive manual effort
for compliance. Specifically, the number of small wet scrubbers subject
to the cited provisions can be 100 or more at a facility. The emissions
from one of the small scrubbers represent a very small fraction of the
total facility emissions. The emissions improvement available by the
periodic checks required by the cited provisions represents an
exceedingly low fraction of the total facility emissions. The labor
hours required for the monthly transducer checks, the quarterly gauge
calibration checks, and the semiannual flow sensor calibration checks is
excessive compared to the potential emissions control improvement. The
labor cost for these checks must be factored into the economic analysis
for this NESHAP. Rather than mandatory monthly, quarterly, or
semi-annual calibration checks, any control unit which emits less than
five percent (5%) of the total annual PM emissions at the facility,
should be allowed reduce the periodic checks required by each of the
cited provisions to once annually.

#### e. Pluggage Checks and Electrical Continuity Checks

Section 63.9632(b)(1)(iii) mandates daily pressure tap pluggage check,
whereas Sections 63.9632(b)(1)(vi) and 63.9632(b)(2)(iv) mandate monthly
electrical connection continuity checks. These provisions are overly
burdensome and costly to implement. There are literally thousands of
electrical connections in each water flow meter monitoring system and
each air pressure measuring system. There are electronic components from
the field sensors to the central process computer and the cable network.
The manual labor and clock hours required for such continuity checks
would be so large that the monitoring systems would have to be shutdown
so frequently and of such a duration that they would have virtually no
operating time. The labor cost for the continuity checks must be
factored into the economic analysis for this NESHAP. These provisions
should be modified so as to provide that "A program within the CPMS to
alarm the process unit operator and to record the alarm for a zero value
indication and for a static value indication satisfies the requirement
of this provision".

### 7. Notification, Recordkeeping, and Reporting Requirements

Section II.F. addresses the notification, recordkeeping, and reporting
requirements. We have several comments on these provisions. First, there
is a requirement for an initial notification. Since the sources
regulated under this source category are all existing sources, we know
that they effectively already submitted initial notification to their
respective state agencies (on or before May 15, 2002) under the
requirements of Section 112(j) of the CAA and General Provisions of Part
63, i.e., the Part 1 applications. (40 C.F.R. § 63.53). Therefore, there
should be no requirement to re-notify under this NESHAP standard. It is
an unnecessary administrative exercise.

Also, this section of the preamble describes the semiannual reporting
requirements of the rule. Two provisions of this section pose conflicts
with applicable ROP requirements. First, there is a requirement in the
rule to submit semiannual reports 30 days after the end of the reporting
period. This conflicts with state reporting requirements in Michigan.
(Semiannual reports are due September 15^th^ for the period between
January 1^st^ and June 30^th^; and March 15^th^ for the period covering
July 1^st^ through December 31^st^. Semiannual reports for this NESHAP
should be submitted as required by the ROP.

In addition, the rule requires that if there are no deviations during a
compliance period, then an affirmative statement be submitted in the
semiannual report. The ROP programs in Michigan and Minnesota require
sources to use state generated forms for semiannual reports. These forms
do not provide for making such a statement specific to individual NESHAP
rules. Instead the forms require that the company certify compliance
except for the deviations reported. There is no reason for the NESHAP to
require anything separate or different from that already required by the
ROP. In short, since all eight of the affected facilities have already
received and are operating under ROPs, semiannual reports for this
NESHAP should be the same document as the semiannual reports submitted
under the applicable ROP.

# III. General Comments

Although this proposed rule does not address any innovative risk-based
approaches to regulating HAPs, we strongly support that type of approach
for sources posing little or no risk to public health or the
environment. The Taconite Iron Ore Processing source category only
applies to 8 operations. The emissions from these operations are
relatively low compared to most industrial operations, i.e.,
approximately 900 tons per year industry-wide. The material handling
operations are already controlled for particulate matter. (67 Fed. Reg.
77562 @ 77565) The preamble states that the "indurating furnaces are the
most significant sources of HAP emissions, accounting for about 99
percent of the total HAP emissions from the taconite iron ore processing
source category." However, these furnaces are also controlled for PM
emissions, e.g., using a multiclone, gravity collector, wet scrubbers,
or electrostatic precipitators. (67 Fed. Reg. 77562 @ 77566)

The proposed rule for this source category will impose severe economic
burdens on an already economically weak industry. Yet, the resulting
emission reductions will be very limited. As a result, taconite iron ore
processing operations are a good example of the type of operation which
should be either delisted from the program altogether, or, if for some
reason that is not possible to accomplish in a timely fashion, then this
source category should be subject to one of the more innovative
risk-based approaches that EPA has proposed recently in various other
NESHAPs including the Brick and Structural Clay Products and Clay
Ceramics NESHAP; the Surface Coating of Automobile and Light-Duty Truck
NESHAP; the Boiler and Process Heater NESHAP; the Wood and Composite
Material NESHAP standard; and the Reciprocating Internal Combustion
Engine NESHAP standard.[^13] We have reviewed these proposals and
believe that EPA has broad discretion in implementing an innovative
approach to satisfy the requirements of Section 112.

## A. Section 112 Explicitly Provides For A Risk Based Approach To Regulating HAPs

We strongly support EPA's attempt in various recently proposed NESHAP
rules to use a risk-based approach to mitigate the impact of section 112
on facilities that "pose little risk to public health and the
environment".[^14] We also agree that without utilizing this approach to
the implementation of section 112, the Agency will require facilities to
expend tremendous capital resources to control emissions even though the
current emissions "may not result in exposures which could pose an
excess individual lifetime cancer risk greater than one in one million
or which exceed thresholds determined to provide an ample margin of
safety for protecting public health and the environment from the effects
of hazardous air pollutants."[^15]

Specifically, in these recently proposed rules, EPA has indicated an
interest in utilizing a risk-based approach to mitigate the impact of
Section 112 on facilities that "pose little risk to public health and
the environment".[^16] We also agree that without utilizing this
approach to the implementation of Section 112, the Agency will require
facilities to expend tremendous capital resources to control emissions
even though the current emissions "may not result in exposures which
could pose an excess individual lifetime cancer risk greater than one in
one million or which exceed thresholds determined to provide an ample
margin of safety for protecting public health and the environment from
the effects of hazardous air pollutants."[^17]

From a public policy perspective, a health risk-based approach to
implementing section 112 is appropriate so as to focus the Agency's
limited resources on industries and emissions that pose unacceptable
risks to public health. Such a focused approach is not only consistent
with the clear language of the CAA, but it is also consistent with the
goals of the Act.

### 1. Summary of Legal Framework for Regulating HAPs Under the CAA

The 1990 Amendments to the Clean Air Act[^18] ("CAA" or "Act")
effectively re-wrote section 112 which contains the provisions of the
Act addressing Hazardous Air Pollutants ("HAPs"). Under the 1990 CAA,
EPA is regulating approximately 170 source categories which emit one or
more of the 188 chemicals and compounds denoted by Congress as Hazardous
Air Pollutants.[^19] To date, EPA has primarily regulated the source
categories using very stringent technology-based standards. EPA has done
very little with the statutory authority granted to them regarding
risk-based standards under section 112.

Section 112(d) requires the EPA to "promulgate regulations establishing
emission standards for each category or subcategory of major sources and
area sources of hazardous air pollutants listed for regulation".[^20] 42
U.S.C. § 7412(d)(1). The Act goes on to provide that these emission
standards be: 1) applicable to new and existing sources; 2) require the
maximum degree of reduction in emissions of HAPs (often referred to as
"Maximum Achievable Control Technology" emission limitation or
"MACT")[^21] that the Administrator deems achievable considering "the
cost of achieving such emission reduction, any non-air quality health
and environmental impacts and energy requirements" 42 U.S.C. §
7412(d)(2).

The Act does allow a less stringent MACT standard be imposed on existing
sources. For source categories with 30 or more sources, section
112(d)(3)(A) defines existing source MACT as "the average emission
limitation achieved by the best performing 12 percent of existing
sources". This determination is to be made excluding those sources that
have been subject to lowest achievable emission rate technology "within
18 months before the emission standard is proposed or with 30 months
before such standard is promulgated, whichever is later". 42 U.S.C. §
7412(d)(3)(A). For source categories (or subcategories) with less than
30 sources, existing source MACT is defined as "the average emission
limitation achieved by the best performing 5 sources" in the category.
42 U.S.C. § 7412(d)(3)(B). The Taconite Ore Processing source category
only contains 8 processing operations and thus, if subject to any MACT,
falls under this latter means of defining MACT.

In addition to the provision for technology-based standards under
section 112(d)(3), the CAA also contains a provision under section
112(d) which allows the Administrator to consider "health thresholds"
with an "ample margin of safety" when establishing emission standards.
Specifically, section 112(d)(4) states:

\(4\) Health threshold.- With respect to pollutants for which a health
threshold has been established, the Administrator may consider such
threshold level, with an ample margin of safety, when establishing
emission standards under this subsection.

The CAA does not define the term "threshold" nor does it define the term
"health threshold". However, the intent of these terms can be understood
in the context of the risk and health based provisions of the CAA
(particularly Sections 112(c) and (f)).

### 2. Detailed Analysis of Legal Framework of Section 112 for Regulating HAPs

[]{#__RefHeading___Toc33352029 .anchor}**a. Section 112(b) -- List of
HAPs**

Expressing dissatisfaction with EPA's implementation of section 112
under the 1970 CAA, Congress completely rewrote the requirements of the
NESHAP program.[^22] Rather than giving the EPA a blank slate as to the
chemicals to be regulated, Congress provided an initial list of 189
HAPs.

To develop this list, Congress looked to other environmental regulatory
programs such as the list of substances regulated under the Emergency
Planning and Community Right to Know Act ("EPCRA"), EPA's
"high-priority" environmental pollutants from section 104(i) of the
Comprehensive Environmental Response, Compensation, and Liability Act
("CERCLA"), and EPA's National Air Toxic Information Clearinghouse.[^23]
EPA reviewed the list and made several suggestions for both additions
and deletions from the initial list. This initial list, though slightly
different from the final list (in that it did not contain hydrogen
sulfide nor ammonia) was then adopted by the conference committee.[^24]
Although some of the chemicals were listed for their toxicity, many of
the substances listed were not necessarily the most toxic compounds, but
instead were compounds with relatively wide-spread industrial use. The
Act provides that the Administrator periodically review the list and
revise it by adding:

> pollutants which present, or may present, through inhalation or other
> routes of exposure, a threat of adverse human health effects
> (including, but not limited to, substances which are known to be, or
> may reasonably be anticipated to be, carcinogenic, mutagenic,
> teratogenic, neurotoxic, which cause reproductive dysfunction, or
> which are acutely or chronically toxic) or adverse environmental
> effects whether through ambient concentrations, bioaccumulation,
> deposition, or otherwise, but not including releases subject to
> regulation under subsection (r) as a result of emissions to the air.
> 42 U.S.C. §7412(b)(2)

Thus, in contrast to the 1970 CAA's focus on carcinogens under section
112, the pollutants regulated under the 1990 version of section 112 need
not be carcinogens, but instead may well be substances which pose
essentially any human health effects. In addition to the Administrator's
requirement to review and revise the list ("HAP list"), section
112(b)(3) allows "any person" to petition the Administrator to modify
the list by either adding or deleting substances. 42 U.S.C. §7412(b)(3).
Additions to the list require a showing that the "emissions, ambient
concentrations, bioaccumulation or deposition of the substance are known
to cause or may reasonably be anticipated to cause adverse effects to
human health or adverse environmental effects." 42 U.S.C.
§7412(b)(3)(B). To delete a substance from the list, there must be
"adequate data on the health and environmental effects of the substance
to determine that emissions, ambient concentrations, bioaccumulation or
deposition of the substance may not reasonably be anticipated to cause
any adverse effects to the human health or adverse environmental
effects." 42 U.S.C. §7412(b)(3)(C).

[]{#__RefHeading___Toc33352030 .anchor}**b. Section 112(c) -- List of
Source Categories**

The Act goes on to require that EPA develop a list of "all categories
and subcategories of major sources and area sources" responsible for
emitting the pollutants on the HAP list. For purposes of section 112, a
"major source" is defined as "any stationary source or group of
stationary sources located within a contiguous area and under common
control that emits or has the potential to emit considering controls, in
the aggregate, 10 tons per year or more of any hazardous air pollutant
or 25 tons per year or more of any combination of hazardous air
pollutants." 42 U.S.C. §7412(a)(1).[^25]

EPA published their first "draft" list of source categories for public
comment on June 21, 1991.[^26] The "final" initial list was published a
little over a year later on July 16, 1992.[^27] The 1992 list focused
primarily on major source categories. EPA stated that "the Agency agrees
that the language of section 112(c)(3) clearly requires that a finding
be made of threat of adverse effects to human health or the environment
warranting regulation under section 112 in order for a category of area
sources to be listed. Hence, the Agency has removed all categories from
today\'s list for which: (1) the available information indicates that
the category contains only area sources, and (2) the Agency has
insufficient information at this time to make a finding of threat of
adverse effects warranting regulation."[^28] The list of source
categories has been modified numerous times since 1992.

[]{#__RefHeading___Toc33352031 .anchor}**c. Section 112(d) -- Emission
Standards**

Section 112(d) then requires the EPA to "promulgate regulations
establishing emission standards for each category or subcategory of
major sources and area sources of hazardous air pollutants listed for
regulation".[^29] 42 U.S.C. § 7412(d)(1). The Act goes on to provide
that these emission standards be: 1) applicable to new and existing
sources; 2) require the maximum degree of reduction in emissions of HAPs
(often referred to as "Maximum Achievable Control Technology" emission
limitation or "MACT")[^30] that the Administrator deems achievable
considering "the cost of achieving such emission reduction, any non-air
quality health and environmental impacts and energy requirements" 42
U.S.C. § 7412(d)(2).

Section 112(d)(3) however appears to negate the consideration of "the
cost of achieving such emission reduction, any non-air quality health
and environmental impacts and energy requirements" by defining MACT for
new sources as not less stringent "than the emission control that is
achieved in practice by the best controlled similar source"[^31]. The
Act does allow a less stringent MACT standard be imposed on existing
sources. For source categories with 30 or more sources, section
112(d)(3)(A) defines existing source MACT as "the average emission
limitation achieved by the best performing 12 percent of existing
sources". This determination is to be made excluding those sources that
have been subject to lowest achievable emission rate technology "within
18 months before the emission standard is proposed or with 30 months
before such standard is promulgated, whichever is later". 42 U.S.C. §
7412(d)(3)(A). For source categories (or subcategories) with less than
30 sources, existing source MACT is defined as "the average emission
limitation achieved by the best performing 5 sources" in the category.
42 U.S.C. § 7412(d)(3)(B).

In addition to the provision for technology-based standards under
section 112(d)(3), the CAA also contains a provision under section
112(d) which allows the Administrator to consider "health thresholds"
with an "ample margin of safety" when establishing emission standards.
Specifically, section 112(d)(4) states:

> \(4\) Health threshold.- With respect to pollutants for which a health
> threshold has been established, the Administrator may consider such
> threshold level, with an ample margin of safety, when establishing
> emission standards under this subsection.

EPA has not made much use of this provision to date. Up until June 2002,
the most prominent NESHAP rulemaking discussing this provision was the
1998 proposal for the Pulp and Paper industry.[^32] More recently, EPA
has proposed to use section 112(d)(4) to not regulate chlorine and
hydrochloric acid emissions for the Chlorine Production source category.
In both cases, EPA used the authority of section 112(d)(4) to not
regulate the affected HAPs on the grounds that the emissions were below
threshold values and within an ample margin of safety.

In the proposed Chlorine Production rule, EPA states that the Agency has

> the discretion under section 112(d)(4) to develop risk-based standards
> which may be less stringent than the corresponding floor-based MACT
> standards for some categories emitting threshold pollutants". The
> evaluation they conducted included an assessment that "every source in
> the category or subcategory are less than the threshold level for an
> individual exposed at the upper end of the exposure distribution. The
> upper end of the exposure distribution is calculated using the "high
> end exposure estimate," defined as a plausible estimate of individual
> exposure for those persons at the upper end of the exposure
> distribution, conceptually above the 90^th^ percentile, but not higher
> than the individual in the population who has the highest exposure. We
> believe that assuring protection to persons at the upper end of the
> exposure distribution is consistent with the "ample margin of safety"
> requirement in section 112(d)(4).

In this proposed rule, EPA stressed that the use of section 112(d)(4)
was "wholly discretionary". The Agency also indicated that in evaluating
whether or not to use the authority of section 112(d)(4), other
considerations such as uncertainty and potential "adverse environmental
effects" would be taken into account.

EPA goes on to discuss the methodology used for the risk assessment.
Although EPA states that the methodology is not to be interpreted as a
standardized approach nor any sort of precedent for the use of section
112(d)(4) in the future.

[]{#__RefHeading___Toc33352032 .anchor}**d. Section 112(f) -- Standard
to Protect Health and Environment**

Section 112(f), often referred to as the "residual risk" provision of
the 1990 CAA, provides that "within 8 years after promulgation of
standards for each category or subcategory of sources pursuant to
subsection (d) of this section, promulgate standards for such category
or subcategory if promulgation of such standards is required in order to
provide an ample margin of safety to protect public health in accordance
with this section (as in effect before November 15, 1990) or to prevent,
taking in consideration costs, energy, safety and other relevant
factros, an adverse environmental effect." 42 U.S.C. § 7412(f)(2).

The Act goes on to provide that:

> emission standards promulgated under this subsection shall provide an
> ample margin of safety to protect public health in accordance with
> this section (as in effect before the date of enactment of the Clean
> Air Act Amendments of 1990), unless the Administrator determines that
> a more stringent standard is necessary to prevent, taking into
> consideration costs, energy, safety, and other relevant factors, an
> adverse environmental effect. If standards promulgated pursuant to
> subsection (d) and applicable to a category or subcategory of sources
> emitting a pollutant (or pollutants) classified as a known, probable
> or possible human carcinogen do not reduce lifetime excess cancer
> risks to the individual most exposed to emissions from a source in the
> category or subcategory to less than one in one million, the
> Administrator shall promulgate standards under this subsection for
> such source category. (B) Nothing in subparagraph (A) or in any other
> provision of this section shall be construed as affecting, or applying
> to the Administrator\'s interpretation of this section, as in effect
> before the date of enactment of the Clean Air Act Amendments of 1990
> and set forth in the Federal Register of September 14, 1989 (54
> Federal Register 38044). 42 U.S.C. § 7412(f)(2)

By specifically referring to provisions "in effect before the date of
enactment of the Clean Air act Amendments of 1990" and citing to the
Benzene NESHAP (promulgated under the pre-1990 section 112),[^33]
Congress appears to be explicitly approving the risk methodology set
forth in the D.C. Circuit's *Vinyl Chloride* decision[^34] and followed
by EPA in the Benzene NESHAP. This explicit approval appears to provide
some additional definition of how Congress intended risk to be addressed
under the 1990 CAA.

Unfortunately, there is some indication in the legislative history and
in the Vinyl Chloride decision and related documents (including EPA's
guidelines for carcinogenic risk assessment) that carcinogens are
"non-threshold" compounds. Although not necessarily supportable by
science, it is a common practice to assume a linear model for the dose
response curve for carcinogens which then indicates that any dose of a
carcinogen, no matter how small, will result in a response. Hence the
non-threshold label. EPA has indicated that they are willing to consider
alternative methodologies, but has not finalized any such procedures or
guidelines.

[]{#__RefHeading___Toc33352033 .anchor}***3. Miscellaneous Provisions of
Section 112 for Regulating HAPs***

EPA has numerous other provisions under Section112 for regulating HAPs.
First and foremost, their initial decisions regarding chemicals to be
regulated, source categories to be listed, levels of emission
limitations to impose, are not eternally binding. To the contrary, the
statute directs EPA to "review and revise" their decisions on a regular
basis, e.g., every 8 years. The fact that Congress explicitly provided
that for this "reconsideration" is clear evidence that they saw the
process of regulating HAPs as iterative in the sense that as technology
improves, and as the science advances towards greater understanding of
what constitutes a true risk, EPA can re-evaluate the emission
limitations set under Section 112 (both the technology and risk-based
emission limits) and revise them as necessary.

In addition to the program for regulating HAPs from major sources, the
1990 CAA amendments also included miscellaneous provisions allowing for
the regulation of HAPs. For example, in addition to major sources,
Congress specifically included a provision for the regulation of
non-major, i.e., area sources. Specifically, Section 112(k) provides:

> \(k\) AREA SOURCE PROGRAM.--- (1) FINDINGS AND PURPOSE.---The Congress
> finds that emissions of hazardous air pollutants from area sources may
> individually, or in the aggregate, present significant risks to public
> health in urban areas. Considering the large number of persons exposed
> and the risks of carcinogenic and other adverse health effects from
> hazardous air pollutants, ambient concentrations characteristic of
> large urban areas should be reduced to levels substantially below
> those currently experienced. It is the purpose of this subsection to
> achieve a substantial reduction in emissions of hazardous air
> pollutants from area sources and an equivalent reduction in the public
> health risks associated with such sources including a reduction of not
> less than 75 per centum in the incidence of cancer attributable to
> emissions from such sources.[^35]

In addition, Section 112(k) goes on to require EPA to develop a national
strategy for regulating "emissions of hazardous air pollutants from area
sources in urban areas."[^36] Specifically, the CAA provides:

> \(B\) The strategy shall--- (i) identify not less than 30 hazardous
> air pollutants which, as the result of emissions from area sources,
> present the greatest threat to public health in the largest number of
> urban areas and that are or will be listed pursuant to subsection (b),
> and (ii) identify the source categories or subcategories emitting such
> pollutants that are or will be listed pursuant to subsection (c). When
> identifying categories and subcategories of sources under this
> subparagraph, the Administrator shall assure that sources accounting
> for 90 per centum or more of the aggregate emissions of each of the 30
> identified hazardous air pollutants are subject to standards pursuant
> to subsection (d).

Also, the CAA requires EPA to provide updated status reports to Congress
regarding the risks that area sources are providing to public
health.[^37]

In addition urban air toxics, Section 112(m) of the 1990 CAA amendments
also contained specific provisions for addressing atmospheric deposition
of HAPs to the Great Lakes and other precious water systems. Moreover,
there are numerous provisions for advancing the science required for
developing appropriate regulations under Section 112 and for EPA to
formally report to Congress.

[]{#__RefHeading___Toc33352034 .anchor}***4. Section 112 of the CAA
allows EPA Considerable Discretion as to How to Regulate HAPs***

As described above, EPA have numerous paths of which to avail themselves
for regulating HAPs. They can regulate major sources, minor sources,
sources posing high risks, sources located in urban areas, etc. The
level of discretion provided to EPA by Congress under the CAA is
consistent with allowing EPA to utilize any approach necessary to arrive
at useful, meaningful, and productive regulations which are productive
of public health. Nothing in the CAA requires EPA to regulate sources
which are not posing an unacceptable risk to the public health or
environment.[^38]

### 

## B. EPA Has the Authority to Implement and Utilize a Risk-Based Approach to Section 112 of the CAA

EPA has recently proposed several innovative risk-based approaches to
implementing Section 112. Recently proposed NESHAP standards such as the
Brick and Structural Clay Products and Clay Ceramics MACT, the Surface
Coating of Automobile and Light-Duty Truck MACT, the Boiler and Process
Heater MACT, the Wood and Composite Material MACT standard, and the
Reciprocating Internal Combustion Engine MACT standard.[^39] These
proposals discuss EPA's broad discretion in implementing an innovative
approach to satisfy the requirements of Section 112.

Specifically, in these recently proposed rules, EPA has indicated an
interest in utilizing a risk-based approach to mitigate the impact of
Section 112 on facilities that "pose little risk to public health and
the environment".[^40] We also agree that without utilizing this
approach to the implementation of Section 112, the Agency will require
facilities to expend tremendous capital resources to control emissions
even though the current emissions "may not result in exposures which
could pose an excess individual lifetime cancer risk greater than one in
one million or which exceed thresholds determined to provide an ample
margin of safety for protecting public health and the environment from
the effects of hazardous air pollutants."[^41]

From a public policy perspective, a health risk-based approach to
implementing Section 112 is appropriate so as to focus the Agency's
limited resources on industries and emissions that pose unacceptable
risks to public health. Such a focused approach is not only consistent
with the clear language of the CAA, but it is also consistent with the
goals of the Act.

### 1. Summary of Legal Framework for Utilizing a Risk Based Approach to Regulating HAPs Under the CAA

The 1990 Amendments to the Clean Air Act[^42] ("CAA" or "Act")
effectively re-wrote Section 112 which contains the provisions of the
Act addressing Hazardous Air Pollutants ("HAPs"). Under the 1990 CAA,
EPA is regulating approximately 170 source categories which emit one or
more of the 188 chemicals and compounds denoted by Congress as Hazardous
Air Pollutants.[^43] To date, EPA has primarily regulated the source
categories using very stringent technology-based standards. EPA has done
very little with the statutory authority granted to them regarding
risk-based standards under Section 112.

Section 112(d) requires the EPA to "promulgate regulations establishing
emission standards for each category or subcategory of major sources and
area sources of hazardous air pollutants listed for regulation".[^44] 42
U.S.C. § 7412(d)(1). The Act goes on to provide that these emission
standards be: 1) applicable to new and existing sources; 2) require the
maximum degree of reduction in emissions of HAPs (often referred to as
"Maximum Achievable Control Technology" emission limitation or
"MACT")[^45] that the Administrator deems achievable considering "the
cost of achieving such emission reduction, any non-air quality health
and environmental impacts and energy requirements" 42 U.S.C. §
7412(d)(2).

The Act allows a less stringent MACT standard be imposed on existing
sources. For source categories with 30 or more sources, Section
112(d)(3)(A) defines existing source MACT as "the average emission
limitation achieved by the best performing 12 percent of existing
sources". This determination is to be made excluding those sources that
have been subject to lowest achievable emission rate technology "within
18 months before the emission standard is proposed or with 30 months
before such standard is promulgated, whichever is later". 42 U.S.C. §
7412(d)(3)(A). For source categories (or subcategories) with less than
30 sources, existing source MACT is defined as "the average emission
limitation achieved by the best performing 5 sources" in the category.
42 U.S.C. § 7412(d)(3)(B).

Most importantly, in addition to the provision for technology-based
standards under Section 112(d)(3), the CAA also contains a provision
under Section 112(d) which allows the Administrator to consider "health
thresholds" with an "ample margin of safety" when establishing emission
standards. Specifically, Section 112(d)(4) states:

\(4\) Health threshold.- With respect to pollutants for which a health
threshold has been established, the Administrator may consider such
threshold level, with an ample margin of safety, when establishing
emission standards under this subsection.

The CAA does not define the term "threshold" nor does it define the term
"health threshold". However, these intent of these terms can be
understood in the context of the risk and health based provisions of the
CAA (including Section 112(c) and 112(f)).

### 

### a. Potential Risk-Based Approaches to Regulating HAPs

Until June 2002, the most prominent NESHAP rulemaking discussing this
provision was the 1998 proposal for the Pulp and Paper industry wherein
EPA decided to handle HCl emissions under the authority of Section
112(d)(4).[^46] This past June, EPA decided to use section 112(d)(4) to
not regulate chlorine and hydrochloric acid emissions for the Chlorine
Production source category. In both cases, EPA used the authority of
section 112(d)(4) to not regulate the affected HAPs on the grounds that
the emissions were below threshold values and within an ample margin of
safety.

In the proposed Chlorine Production rule, EPA states that the Agency has
"the discretion under Section 112(d)(4) to develop risk-based standards
which may be less stringent than the corresponding floor-based MACT
standards for some categories emitting threshold pollutants."[^47] The
evaluation they conducted included an assessment that:

every source in the category or subcategory are less than the threshold
level for an individual exposed at the upper end of the exposure
distribution. The upper end of the exposure distribution is calculated
using the "high end exposure estimate," defined as a plausible estimate
of individual exposure for those persons at the upper end of the
exposure distribution, conceptually above the 90^th^ percentile, but not
higher than the individual in the population who has the highest
exposure. We believe that assuring protection to persons at the upper
end of the exposure distribution is consistent with the "ample margin of
safety" requirement in § 112(d)(4).[^48]

Other recently proposed standards have included the including the Brick
and Structural Clay Products and Clay Ceramics NESHAP,[^49] the Surface
Coating of Automobile and Light-Duty Truck NESHAP[^50] , the Boiler and
Process Heater NESHAP[^51], the Wood and Composite Material NESHAP[^52],
and the Reciprocating Internal Combustion Engine NESHAP.[^53] In
addition to discussing the 112(d)(4) provision for purposes of chlorine
related emissions, these proposals address a much broader approach to
using Section 112(d)(4).

More specifically, EPA has recently proposed several NESHAP rules and is
accepting comments on various approaches to alleviating the cost burdens
of these NESHAP regulations for source categories where the imposition
of the costly MACT controls will result in little benefit to the
environment. Specifically, EPA has proposed to use various alternative
risk-based approaches to address these situations. This approach could
be characterized as "accelerating the "residual risk" analysis provided
in the CAA. Rather than set a MACT standard and wait 8 years to
determine if there are any residual risks, this "accelerated approach"
allows the Agency to evaluate the risks posed by sources in these source
categories. Those source categories, or sources within those categories,
that do not pose unacceptable health risks, based on guidance provided
by the CAA, would not have to undergo further emission reductions. In
short, provisions such as 112(d)(4) which allows for MACT controls to be
based on the level of control required to attain an emission limitation
which provides for an ample margin of safety.

One of the approaches being proposed by EPA involves the use of
"applicability cutoff" for threshold pollutants. This approach would be
implemented under the authority of CAA section 112(d)(4). Generally
speaking, Section 112(d) of the CAA sets for the provisions and criteria
to be used in establishing emission limitations for purposes of MACT
standards.

The second approach proposed by EPA involves creating subcategories and
then delisting those subcategories that meet the criteria set forth in
Section 112(c)(1) and (c)(9) of the CAA. In short, Section 112(c)(9)
allows EPA to avoid setting MACT standards for categories or
subcategories of sources that pose less than a specified level of risk
to public health and the environment.

The third approach involves the use of a concentration-based
applicability threshold. There is also a fourth approach, though not
specifically addressed in the proposal set forth to date, and that
involves the EPA's broad *de minimis* authority under the CAA. This *de
minimis* authority could also be imposed to reduce the imposition of
costly regulations which provide little or no environmental or public
health benefits.

#### 1. Applicability Cutoff for Threshold Pollutants Under Section 112(d)(4)

As described by EPA, the applicability cutoff approach could be handled
three different ways.

> The first approach is an "applicability cutoff" for threshold
> pollutants that is based on EPA's authority under CAA section
> 112(d)(4) to establish standards for HAP which are "threshold
> pollutants." A "threshold pollutant" is one for which there is a
> concentration or dose below which adverse effects are not expected to
> occur over a lifetime of exposure. For such pollutants, section
> 112(d)(4) allows EPA to consider the threshold level, with an ample
> margin of safety, when establishing emission standards. Specifically,
> section 112(d)(4) allows EPA to establish emission standards that are
> not based upon the MACT specified under section 112(d)(2) for
> pollutants for which a health threshold has been established. Such
> standards may be less stringent than MACT. Historically, EPA has
> interpreted section 112(d)(4) to allow categories of sources that emit
> only threshold pollutants to avoid further regulation if those
> emissions result in ambient levels that do not exceed the threshold,
> with an ample margin of safety.[^54]

The Agency goes on to state:

> A different interpretation would allow us to exempt individual
> facilities within a source category that meet the section 112(d)(4)
> requirements. There are three potential scenarios under this
> interpretation of the section 112(d)(4) provision. One scenario would
> allow an exemption for individual facilities that emit only threshold
> pollutants and can demonstrate that their emissions of threshold
> pollutants would not result in air concentrations above the threshold
> levels, with an ample margin of safety, even if the category is
> otherwise subject to MACT. A second scenario would allow the section
> 112(d)(4) provision to be applied to both threshold and non-threshold
> pollutants, using the 1 in 1 million cancer risk level for
> decision-making for non-threshold pollutants.
>
> A third scenario would allow a section 112(d)(4) exemption at a
> facility that emits both threshold and non-threshold pollutants. For
> those emission points where only threshold pollutants are emitted and
> where emissions of the threshold pollutants would not result in air
> concentrations above the threshold levels, with an ample margin of
> safety, those emission points could be exempt from the MACT standards.
> The MACT standards would still apply to non-threshold emissions from
> other emission points at the source. For this third scenario, emission
> points that emit a combination of threshold and non-threshold
> pollutants that are co-controlled by MACT would still be subject to
> the MACT level of control. However, any threshold HAP eligible for
> exemption under section 112(d)(4) that are controlled by control
> devices different from those controlling non-threshold HAP would be
> able to use the exemption, and the facility would still be subject to
> the sections of the standards that control non-threshold pollutants or
> that control both threshold and non-threshold pollutants.

Importantly, though not necessarily correctly, EPA appears to interpret
that the term "threshold" itself seems to exclude "carcinogens" on the
basis that carcinogens are generally considered by the EPA to not have
any threshold (i.e., they pose some response regardless of the dose of
the exposure). For example, the Agency has asserted that exposure to
even one molecule of a carcinogenic agent can cause cancer. Besides
being absurd, particularly given that it is highly likely that all
Americans have come into contact with at least one molecule of a
carcinogen and not all Americans have cancer, this theory also ignores
the inherent "legal threshold" for carcinogens that congress put into
the Clean Air Act, i.e., "lifetime excess cancer risks to the individual
most exposed to emissions from a source in the category or subcategory
to less than one in one million".[^55]

At a minimum, EPA's proposed second approach under the "applicability
cut-off" approach should be adopted, i.e., that Section112(d)(4)
provision "be applied to both threshold and non-threshold pollutants,
using the 1 in 1 million cancer risk level for decision-making for
non-threshold pollutants." This approach is consistent with the
Congressional use of the term "threshold" as well as the approach taken
by the D.C. Circuit court in *NRDC v. EPA* which is discussed in detail
below. *NRDC v. EPA*, 824 F.2d 1146 (1987) (Finding that something is
"safe" does not mean it is "risk-free").

#### 2. Hazard Quotients and Indices

EPA states that under the section 112(d)(4) approach, EPA would have to
determine that emissions of each of the threshold pollutants emitted by
operations at the facility would not result in exposures which exceed
the threshold levels, with an ample margin of safety. EPA methodology
provides that the

> common approach for evaluating the potential hazard of a threshold air
> pollutant is to calculate a "hazard quotient" by dividing the
> pollutant's inhalation exposure concentration (often assumed to be
> equivalent to its estimated concentration in air at a location where
> people could be exposed) by the pollutant's inhalation Reference
> Concentration (RfC). An RfC is an estimate (with uncertainty spanning
> perhaps an order of magnitude) of a continuous inhalation exposure
> that, over a lifetime, likely would not result in the occurrence of
> adverse health effects in humans, including sensitive individuals.

The Agency goes on to state:

> The EPA typically establishes an RfC by applying uncertainty factors
> to the critical toxic effect derived from the lowest- or
> no-observed-adverse-effect level of a pollutant[^56]. A hazard
> quotient less than one means that the exposure concentration of the
> pollutant is less than the RfC and, therefore, presumed to be without
> appreciable risk of adverse health effects. A hazard quotient greater
> than one means that the exposure concentration of the pollutant is
> greater than the RfC. Further, EPA guidance for assessing exposures to
> mixtures of threshold pollutants recommends calculating a hazard index
> (HI) by summing the individual hazard quotients for those pollutants
> in the mixture that affect the same target organ or system by the same
> mechanism[^57]. The HI values would be interpreted similarly to hazard
> quotients; values below one would generally be considered to be
> without appreciable risk of adverse health effects, and values above
> one would generally be cause for concern.
>
> To establish an applicability cutoff under section 112(d)(4), EPA
> would need to define ambient air exposure concentration limits for any
> threshold pollutants involved. There are several factors to consider
> when establishing such concentrations. First, we would need to ensure
> that the concentrations that would be established would protect public
> health with an ample margin of safety. As discussed above, the
> approach EPA commonly uses when evaluating the potential hazard of a
> threshold air pollutant is to calculate the pollutant's hazard
> quotient, which is the exposure concentration divided by the RfC.

#### 3. Tiered analytical approach for predicting exposure. 

In the proposed NESHAP for Plywood and Composite Wood Products, EPA goes
on to discuss a "tiered analytical approach for predicting exposure" for
purposes of implementing a risk-based MACT emission limitation.
Specifically, EPA states that:

> Establishing that a facility meets the cutoffs established under
> section 112(d)(4) will necessarily involve combining estimates of
> pollutant emissions with air dispersion modeling to predict exposures.
> The EPA envisions that we would promote a tiered analysis for these
> determinations. A tiered analysis involves making successive
> refinements in modeling methodologies and input data to derive
> successively less conservative, more realistic estimates of pollutant
> concentrations in air and estimates of risk.
>
> As a first tier of analysis, EPA could develop a series of simple
> look-up tables based on the results of air dispersion modeling
> conducted using conservative input assumptions. By specifying a
> limited number of input parameters, such as stack height, distance to
> property line, and emission rate, a facility could use these look-up
> tables to determine easily whether the emissions from their sources
> might cause a HI limit to be exceeded.
>
> A facility that does not pass this initial conservative screening
> analysis could implement increasingly more site-specific and
> resource-intensive tiers of analysis using EPA-approved modeling
> procedures in an attempt to demonstrate that exposure to emissions
> from the facility does not exceed the HI limit. Existing EPA guidance
> could provide the basis for conducting such a tiered analysis[^58].

Moreover, states with existing and mature air toxics programs could be
delegated such responsibility under Section 112(l) of the CAA.

#### 4. Accounting for dose-response relationships. 

Traditionally, EPA has considered carcinogens to be non-threshold
pollutants. The Agency appears to be re-evaluating that position as
evidenced by the 1999 draft "Guidelines for Carcinogen Risk
Assessment."[^59] Not only do these guidelines imply that carcinogens
may have non-linear dose-response relationships, but that for some
pollutants, there may well be a threshold wherein the response would not
be measured until some dose above zero were administered. In short,
according to EPA there could be carcinogens that will clearly be
threshold compounds.[^60]

In the various recent rulemakings wherein EPA proposes risk-based
approaches EPA requests comment on how to handle the threshold issue.
Clearly if a carcinogen demonstrates that it has a threshold
dose-response curve, then it should be considered a threshold compound.
Had Congress intended to restrict the application of Section 112(d)(4)
to non-carcinogens, then Congress would certainly have used the term
"non-carcinogen" rather than "threshold." Instead, as discussed above,
by using the term "threshold," Congress was mandating that there is a
level of exposure below which is acceptable for the protection of public
health. Again, just looking at the provisions of Section 112(c)(9),
Congress makes it clear that not all emissions of all HAPs must be
regulated -- regardless of whether they are carcinogens or
non-carcinogens. Instead, Congress illustrates what they consider to be
an appropriate threshold. Specifically, in Section 112(c)(9) (which
addresses the criteria for delisting source categories), Congress
states:

\(9\) Deletions from the list.

\(A\) Where the sole reason for the inclusion of a source category on
the list required under this subsection is the emission of a unique
chemical substance, the Administrator shall delete the source category
from the list if it is appropriate because of action taken under either
subparagraphs (C) or (D) of subsection (b)(3).

\(B\) The Administrator may delete any source category from the list
under this subsection, on petition of any person or on the
Administrator\'s own motion, whenever the Administrator makes the
following determination or determinations, as applicable:

\(i\) In the case of hazardous air pollutants emitted by sources in the
category that may result in cancer in humans, a determination that no
source in the category (or group of sources in the case of area sources)
emits such hazardous air pollutants in quantities which may cause a
**lifetime risk of cancer greater than one in one million to the
individual in the population who is most exposed to emissions of such
pollutants** from the source (or group of sources in the case of area
sources).

\(ii\) In the case of hazardous air pollutants that may result in
**adverse health effects in humans other than cancer or adverse
environmental effects,** a determination that emissions from no source
in the category or subcategory concerned (or group of sources in the
case of area sources) exceed a level which is **adequate to protect
public health with an ample margin of safety and no adverse
environmental effect** will result from emissions from any source (or
from a group of sources in the case of area sources). The Administrator
shall grant or deny a petition under this paragraph within 1 year after
the petition is filed. *(emphasis added)*

Similarly, in Section 112(f)(2) Congress again discusses the concept of
"threshold" by requiring the Agency to evaluate residual risks so as to
ensure that there was "an ample margin of safety" and, for carcinogens,
a limit on "lifetime excess cancer risks to the individual most exposed
to emissions . . . to less than one in one million. Again, even for
those compounds which have not necessarily demonstrated a "threshold" to
EPA, and which may or may not be a carcinogen, EPA must consider that by
using the guidance set forth by Congress, all compounds have a
threshold.

#### 5. Risk assessment results 

In the various risk based proposals, EPA expresses great concern
regarding the uncertainty surrounding "quantifying exposure, risk, and
cancer incidence that carry significant assumptions, uncertainties, and
limitations." The rules can address this by the very nature of the
methodology that will be used and by the very conservative nature of the
assessments of exposures and toxicity. Clearly it is not yet an exact
science, but Congress foresaw that and thus requires EPA to revisit
NESHAP standards every 8 years and to advance the study of health and
environmental impacts from HAPs (as described in Section 112(f)) so that
as science and the state of knowledge progresses, the new information
can be taken into account in future regulations.

Any program involving risk assessment for HAPs should carefully include
ALL aspects of traditional risk assessment including hazard
identification, dose-response assessment, exposure assessment, and risk
characterization, and finally, risk management. The simplest approach
would be to set up a tiered approach wherein a relatively simple
analyses could be conducted by the company to determine if they met
"screening" criteria for meeting the health risk-based emissions
limitations. If so, then the requirements are met, if not, then further
assessment using more site-specific, refined information including more
accurate exposure assessments and evaluations of uncertainty in both
dose-response assessments and modeling exercises.

### b. Subcategory Delisting Under Section 112(c)(9)(B) of the CAA

EPA has broad discretion to tailor source categories as appropriate to
best reflect the source category. Specifically, the statute provides
that EPA:

> establish categories and subcategories of sources, as appropriate,
> pursuant to CAA section 112(c)(1), in order to facilitate the
> development of MACT standards consistent with section 112 of the CAA.
> Further, section 112(c)(9)(B) allows EPA to delete a category (or
> subcategory) from the list of major sources for which MACT standards
> are to be developed when the following can be demonstrated: (1) in the
> case of carcinogenic pollutants, that \". . .no source in the
> category. . .emits (carcinogenic) air pollutants in quantities which
> may cause a lifetime risk of cancer greater than 1 in 1 million to the
> individual in the population who is most exposed to emissions of such
> pollutants from the source. . ."; (2) in the case of pollutants that
> cause adverse non cancer health effects, that \". . .emissions from no
> source in the category or subcategory. . .exceed a level which is
> adequate to protect public health with an ample margin of safety. .
> .\"; and (3) in the case of pollutants that cause adverse
> environmental effects, that "no adverse environmental effect will
> result from emissions from any source. . .."[^61]

This level of discretion clearly grants EPA the authority to

> establish subcategor\[ies\] of facilities within the larger source
> category that would meet the risk-based criteria for delisting. Such
> criteria would likely include the same requirements as described
> previously for the second scenario under the section 112(d)(4)
> approach, whereby a facility would be in the low-risk subcategory if
> its emissions of threshold pollutants do not result in exposure which
> exceed the HI limits, and if its emissions of non-threshold pollutants
> do not result in exposures which exceed a cancer risk level of
> 10-6.[^62]
>
> Since each facility in such a subcategory would be a low-risk facility
> (i.e., each would meet these criteria), the subcategory could be
> delisted in accordance with section 112(c)(9), thereby limiting the
> costs and impacts of the proposed MACT rule to only those facilities
> that do not qualify for subcategorization and delisting. The EPA
> estimates that the maximum potential of utilizing this approach would
> be the same as that of applying the section 112(d)(4) approach for
> threshold and non-threshold pollutants, though the actual impact is
> likely to be less.

EPA goes on to state that:

> Facilities seeking to be included in the delisted subcategory would be
> responsible for providing all data required to determine whether they
> are eligible for inclusion. Facilities that could not demonstrate that
> they are eligible to be included in the low-risk subcategory would be
> subject to MACT and possible future residual risk standards.

The concern EPA raised with this approach was that if this delisting
were to occur and then a new MACT floor analysis conducted, it could
lead to a less stringent MACT floor. For purposes of the Taconite Iron
Ore Processing source categories, this could be easily addressed by
leaving the MACT floor as established (with the minor corrections to the
data and the significant figures used in the standard) and, as EPA
suggests, merely "allow low-risk facilities to use the section 112(c)(9)
exemption without affecting the MACT floor calculation. The EPA requests
comment on this suggested approach."[^63]

In these risk based proposals, EPA also suggests that another
alternative approach would be

> to define a subcategory of facilities within the source category based
> upon technological differences, such as differences in production
> rate, emission vent flow rates, overall facility size, emissions
> characteristics, processes, or air pollution control device viability.

The EPA goes on to state that if it was "determined that each source in
this technologically-defined subcategory presents a low risk to the
surrounding community, the subcategory could then be delisted in
accordance with section 112(c)(9)."

The Taconite Iron Ore Processing source category presents an ideal
scenario for this latter approach. For example, the current Taconite
Iron Ore Processing source category includes multiple "affected sources"
and substantially dissimilar types of operations under the singular
heading of one source category. In this instance it would be appropriate
to divide the source category into two source categories: one for the
thermal operations and the other for the material handling operations.
Based on preliminary evaluations, emissions from the material handling
operations present such a low ambient impact, that they easily meet the
criteria set forth in Section 112(c)(9)

### c. Acceptable Levels of Risk

In the recently proposed rulemakings, EPA seems to ponder what
constitutes an acceptable level of risk, particularly for
non-carcinogens. There really is no mystery involved. Congress spoke to
this question in Section 112(f) when it cited to the Benzene NESHAP
stating:

\(2\) Emission standards.

\(A\) If Congress does not act on any recommendation submitted under
paragraph (1), the Administrator shall, within 8 years after
promulgation of standards for each category or subcategory of sources
pursuant to subsection (d), promulgate standards for such category or
subcategory if promulgation of such standards is required in order to
provide an ample margin of safety to protect public health in accordance
with this section (as in effect before the date of enactment of the
Clean Air Act Amendments of 1990) or to prevent, taking into
consideration costs, energy, safety, and other relevant factors, an
adverse environmental effect. Emission standards promulgated under this
subsection shall provide an ample margin of safety to protect public
health in accordance with this section (as in effect before the date of
enactment of the Clean Air Act Amendments of 1990), unless the
Administrator determines that a more stringent standard is necessary to
prevent, taking into consideration costs, energy, safety, and other
relevant factors, an adverse environmental effect. If standards
promulgated pursuant to subsection (d) and applicable to a category or
subcategory of sources emitting a pollutant (or pollutants) classified
as a known, probable or possible human carcinogen do not reduce lifetime
excess cancer risks to the individual most exposed to emissions from a
source in the category or subcategory to less than one in one million,
the Administrator shall promulgate standards under this subsection for
such source category.

\(B\) Nothing in subparagraph (A) or in any other provision of this
section shall be construed as affecting, or applying to the
Administrator\'s interpretation of this section, as in effect before the
date of enactment of the Clean Air Act Amendments of 1990 and set forth
in the Federal Register of September 14, 1989 (54 Federal Register
38044).

Subsection 112(f)(2)(B) explicitly defers to the holding in the
pre-eminent *Vinyl Chloride* case and thus sets for the standards for
evaluating acceptable health limits for Hazardous Air Pollutants.[^64]
For purposes of carcinogens, the standard is clearly a "lifetime excess
cancer risks to the individual most exposed to emissions from a source
in the category or subcategory to less than one in one million."[^65]
This case and the underlying risk issues are discussed in detail
beginning on page 34 of these comments.

Note, contrary to EPA's assertions that Congress may have intended the
concept of a "threshold" compound to automatically mean
"non-carcinogen", is effectively destroyed by the clear and literal
language of Subsection 112(f)(2)(A), i.e., that the provisions for
carcinogens under Section 112(f) are not limited to technology-based
NESHAP standards promulgated under Section 112(d)(3), but instead merely
addresses "standards promulgated pursuant to subsection (d)". Had
Congress intended Section 112(d)(4) to apply only to non-carcinogens,
then it would not have included the provisions of Section 112(d)(4) when
addressing constraints on emissions of carcinogens under Section
112(f)(2)(A). (Also, as mentioned above, there is no indication that
Congress meant the term "threshold" to be a code word for
"non-carcinogen". To the contrary, had Congress intended Section
112(d)(4) to be limited to non-carcinogens, then it would have clearly
stated so by using the term "non-carcinogen".)

## C. EPA Has General Authority To Exempt *De Minimis* Emissions Based on Concentration or Risk

In addition to the strict risk based approach in Section 112(c)(9) or
112(d)(4), EPA also has general authority to exempt *de minimis*
emissions. Emissions could be *de minimis* based on either the quantity
and/or ambient impact of the emissions or by establishing a risk-based
approach to establishing *de minimis* emissions. This approach could be
used for the Taconite Iron Ore Processing source category since many of
the emissions are low enough to be considered *de minimis* on either a
mass emission rate basis, a concentration basis, or even a *de minimis*
risk basis.

### 1. EPA's General De Minimis Authority

The case law under the CAA clearly interprets the CAA as providing EPA
with the authority to create exemptions based on de minimis emissions.
Specifically, in the preeminent case of *Alabama Power Co. v. Costle,*
636 F.2d 323 (D.C. Cir. 1979), the court is clear that the
administrative process allows for the inclusion of exemptions from a
statutory program, unless such exemptions are expressly prohibited by
Congress. Specifically, while addressing EPA's authority, under the
heading of "Exemptions for De Minimis Circumstances," the court stated:

> Categorical **exemptions may** also be permissible as an **exercise of
> agency power**, **inherent in most statutory schemes**, to **overlook
> circums**tances that in context may **fairly be considered de
> minimis**. It is commonplace, of course, that **the law does not
> concern itself with trifling matters**, \[See, e. g., *Washington v.
> Washington State Commercial Passenger Fishing Vessel Ass\'n*, 443 U.S.
> 658, 687 n. 29, 99 S. Ct. 3055, 3076 n. 29, 61 L. Ed. 2d 823 (1979)
> (Indian fishing rights); *Pennsylvania v. Mimms*, 434 U.S. 106, 110,
> 98 S. Ct. 330, 333, 54 L. Ed. 2d 331 (1977) (search and seizure);
> *Ingraham v. Wright*, 430 U.S. 651, 674, 97 S. Ct. 1401, 1414, 51 L.
> Ed. 2d 711 (1977) (due process liberty interest); *Sniadach v. Family
> Finance Corp.*, 395 U.S. 337, 342, 89 S. Ct. 1820, 1823, 23 L. Ed. 2d
> 349 (1969) (Harlan, J., concurring).\] and this principle has often
> found application in the administrative context. See, e. g., *FPC v.
> Texaco*, Inc., 417 U.S. 380, 399, 94 S. Ct. 2315, 2327, 41 L. Ed. 2d
> 141 (1974); *Volkswagenwerk, A.G. v. FMC*, 390 U.S. 261, 276-77, 88 S.
> Ct. 929, 937-38, 19 L. Ed. 2d 1090 (1968); *Monsanto Company v.
> Kennedy*, 198 U.S.App.D.C. 214, 222, 613 F.2d 947, 955 (1979); *United
> Glass & Ceramic Workers v. Marshall*, 189 U.S.App.D.C. 240, 242, 584
> F.2d 398, 440 (1978); *Marine Space Enclosures, Inc. v. FMC*, 137
> U.S.App.D.C. 9, 16, 420 F.2d 577, 584 (1969).\] **Courts should be
> reluctant to apply the literal terms of a statute to mandate pointless
> expenditures of effort**. As we wrote in *District of Columbia v.
> Orleans*, 132 U.S.App.D.C. 139, 141, 406 F.2d 957, 959 (1968),
> **\"(t)he \"de minimis\' doctrine that was developed to prevent
> trivial items from draining the time of the courts has room for sound
> application to administration by the Government of its regulatory
> programs** . . .\" The ability, which we describe here, **to exempt de
> minimis situations from a statutory command is not an ability to
> depart from the statute, but rather a tool to be used in implementing
> the legislative design**. \[In this respect, the principle is a cousin
> of the doctrine that, notwithstanding the \"plain meaning\" of a
> statute, **a court must look beyond the words to the purpose of the
> act where its literal terms lead to [\"absurd or futile
> results]{.underline}**.\" *United States v. American Trucking
> Ass\'ns*, 310 U.S. 534, 543, 60 S. Ct. 1059, 1063, 84 L. Ed. 1345
> (1939); *District of Columbia v. Orleans*, 132 U.S.App.D.C. 139, 141,
> 406 F.2d 957, 959 (1968).\] *(emphasis added)*

The clear language of the case illustrates the types of factors EPA must
look to when determining whether or not an emission could be considered
*de minimis*. It is important to note that the Court cited multiple
cases, all with the same basic message -- that the regulatory agency has
"inherent *de minimis* power" so as to avoid "pointless expenditures of
effort", because the "law does not concern itself with trifling
matters", nor is the Agency required to regulate to the point where the
regulations will lead to "absurd or futile results", but instead to
exercise common sense so as to implement "legislative design" given the
inherent limitations on regulatory and judicial resources. Based on the
discussion in *Alabama Power Co. v. Costle, t*he constraint on the
Agency's *de minimis* authority appears to be that they cannot use it
"depart from the statute."[^66]

### a. EPA Has Authority to Exempt Emissions Which are "Trivial or of No Value" to the Protection of Public Health or the Environment

The *Alabama Power* Court went on to state that the Agency can create
*de minimis* exemptions, as warranted on a case-by-case basis, if
imposing the "plain meaning" of the statute would yield "a gain of
trivial or no value"[^67]. Specifically, the Court stated:

> Determination of when matters are truly *de minimis* naturally will
> turn on the assessment of particular circumstances, and the agency
> will bear the burden of making the required showing. But we think most
> regulatory statutes, including the Clean Air Act, permit such agency
> showings in appropriate cases.
>
> While the difference is one of degree, the difference of degree is an
> important one. Unless Congress has been extraordinarily rigid, there
> is likely a basis for an implication of de minimis authority to
> provide exemption when the burdens of regulation yield a gain of
> trivial or no value.[^68] *Alabama Power Co. v. Costle* 636 F.2d 323,
> 361 (D.C. Cir. 1979).

Hence *Alabama Power* supports the concept that EPA has the authority to
craft de minimis exemptions if, in the Agency's opinion, the strict
implementation of the statute leads to "a gain of trivial or no value"
or "absurd or futile results."[^69]

### b. EPA Has Wrongfully Attempted to Deny this De Minimis Authority

Although EPA attempted to deny this de minimis authority in *National
Lime Association v. EPA,* 233 F.3d 625, (D.C. Cir. 2000), the *National
Lime* case can be distinguished in that the concept of de minimis in
that case was addressed in the narrow context of developing
technology-based MACT floors.[^70] Specifically, the court found, in
part, that the CAA does not provide for exemptions from the emission
standards based upon either **cost concerns** or a source emitting a
***de minimis* quantity** of HAPs **when a MACT floor exists for the
source category**. The *National Lime* court did not address the issue
of the Agency's authority to provide for exemptions based upon either
***de minimis* emissions nor *de minimis* effect** upon human health and
the environment.[^71] Also, we are not arguing that there should be
exemptions based on cost, rather we are arguing that EPA can structure
the MACT rules such that de minimis levels of emissions or de minimis
levels of risks to public health[^72] not be subject to the technology
based standards developed under section 112(d)(3).

### 2. Risk-Based Approach to De Minimis

Promulgation of a technology-based MACT standard under section
112(d)(3), which will provide a "gain of trivial or no value" or which
will result in "absurd or futile results" is unwarranted and clearly not
mandated by the CAA. Instead, EPA can utilize the authority under
section 112(d)(4) to establish the emission standards for the source.
This is effectively a risk-based *de minimis* approach to the
applicability of section 112(d)(3) technology-based standards. In this
sense, EPA is clearly not precluded by statute nor case law from
developing *de minimis* applicability limits under section 112.

Although EPA has the authority to propose and promulgate *de minimis*
exemptions within the NESHAP regulatory scheme, admittedly, this
authority is not absolute. Instead, as discussed above, any exemption
must be limited to addressing situations where the strict implementation
of the statute leads to "a gain of trivial or no value" or "absurd or
futile results."

As addressed in the AF&PA white papers discussed in the recently
proposed NESHAP for Plywood and Composite Wood Products,[^73] *de
minimis* applicability exemptions based on risk and the risk-based
delisting of sources appear to be prime examples of EPA's authority to
consider de minimis and to make the determination of whether a NESHAP
regulation promulgated under Section 112(d)(3) of the Act may result in
"a gain of trivial or no value" or leads to "absurd or futile results"
can be made in terms of the risk to human health and the environment.

### a. The Statute Provides Both Implicit and Explicit De Minimis Authority

This position is supported by the statute itself in that sections
112(c)(9)(B), 112(d)(4), and 112(f)(2)(A) all discuss the objectives of
the section 112(d) standards in terms of the effect of the pollutants on
human health and the environment. None of these provisions require that
HAPs be regulated simply for the sake of regulation. Instead they all
clearly provide some level of guidance as to what constitutes
"acceptable" emissions of HAPs based on the health impact of those
emissions. For example, section 112(c)(9)(B) provides that

> The Administrator may delete any source category from the list \* \*
> \* whenever the Administrator makes the following determination or
> determinations, as applicable: (i) In the case of hazardous air
> pollutants emitted by sources in the category that may result in
> **cancer** in humans, a determination that no source in the category
> (or group of sources in the case of area sources) emits such hazardous
> air pollutants in quantities which may cause a **lifetime risk of
> cancer greater than one in one million to the individual in the
> population** who is most exposed to emissions of such pollutants from
> the source (or group of sources in the case of area sources). (ii) In
> the case of hazardous air pollutants that may result in adverse health
> effects in humans **other than cancer** or adverse environmental
> effects, a **determination that emissions from no sourc**e in the
> category or subcategory concerned (or group of sources in the case of
> area sources) **exceed a level which is adequate to protect public
> health with an ample margin of safety and no adverse environmental
> effect** will result from emissions from any source (or from a group
> of sources in the case of area sources). (*emphasis added*)

Section 112(f)(2)(A) and (B) contains similar language indicating what
level of emission limitation is necessary in order to meet the intent of
the CAA.[^74] Similarly, section 112(d)(4) provides that MACT standards
set under section 112(d)(3) need not be any more stringent than
necessary to protect public health with an ample margin or safety.[^75]
Hence, there is no requirement to control HAPs simply for the purpose of
controlling HAPs, instead the statute provides guidelines which allow
the EPA to consider the level of emissions and the impact of those
emissions when deciding what level of control, if any, is required. In
short, EPA can promulgate a *de minimis* exemption from a technology
based emission limitation based upon such *de minimis* effect upon human
health and the environment.

In proposing and promulgating any exemptions based upon a *de minimis*
effect upon human health and the environment, EPA must exercise judgment
regarding what constitutes a *de minimis* effect. Fortunately, this
principle has already been addressed by both the courts and Congress.

### b. The Caselaw Supports EPA's De Minimis Authority

In *Natural Resources Defense Council v. US EPA* (824 F.2d 1146 (1987))
(also known as the *Vinyl Chloride* case), the Court outlined EPA's
authority for determining what constitutes a de minimis or "safe" level
of exposure to a hazardous air pollutant (HAP), specifically with
respect to carcinogenic HAPs. The court found that:

> the congressional mandate to provide "an ample margin of safety" "to
> protect the public health" requires the Administrator to make an
> initial determination of what is "safe." This determination must be
> based exclusively upon the Administrator's determination of the risk
> to health at a particular emission level. ... We do wish to note,
> however, that **the Administrator's decision does not require a
> finding that "safe" means "risk-free**," *see Industrial Union Dep't,
> 448 U.S. at 642*, **or a finding that the determination is free from
> uncertainty**. Instead, we find only that the Administrator's decision
> must be based upon an expert judgment with regard to the **level of
> emission that will result in an "acceptable" risk to health**.
> *Environmental Defense Fund, 598 F.2d at 83-84*. In this regard, the
> Administrator must determine what inferences should be drawn from
> available scientific data and decide what risks are acceptable in the
> world in which we live. *(emphasis added)*

Thus, EPA is empowered to promulgate a *de minimis* exemption from a
NESHAP based upon the Administrator's determination of an acceptable
level of exposure to a HAP that protects human health and the
environment with an ample margin of safety. Again, EPA's authority in
this matter is clearly expressed in §112(d)(4) which reads:

> Health Threshold. -- With respect to pollutants for which a health
> threshold has been established, the Administrator may consider such
> threshold level, with an ample margin of safety, when establishing
> emission standards under this subsection.

Furthermore, in section 112, Congress provides clear guidance to EPA
regarding what it considers "an ample margin of safety to protect human
health in accordance with this section" (i.e., §112 in whole) for
compounds that may be carcinogens. Specifically, as alluded to earlier,
in section 112(f)(2)(A), Congress states that, unless the EPA determines
that a more stringent standard is necessary, a "safe" level is that
which reduces the risk of excess cancer to the most exposed individual
to less than one in one million. Section 112(f)(2)(A) reads, in part:

> ... Emission standards promulgated under this subsection shall provide
> an ample margin of safety to protect public health in accordance with
> this section (as in effect before the date of enactment of the Clean
> Air Act Amendments of 1990), unless the Administrator determines that
> a more stringent standard is necessary to prevent, taking into
> consideration costs, energy, safety, and other relevant factors, an
> adverse environmental effect. If standards promulgated pursuant to
> subsection (d) and applicable to a category or subcategory of sources
> emitting a pollutant (or pollutants) classified as a known, probable
> or possible human carcinogen do not reduce lifetime excess cancer
> risks to the individual most exposed to emissions from a source in the
> category or subcategory to less than one in one million, the
> Administrator shall promulgate standards under this subsection for
> such source category.

Thus EPA has the authority to determine the "safe" level of exposure to
any HAP and, upon determining such "safe" level, propose and promulgate
exemptions or alternative health-based emission limitations (i.e., under
112(d)(4)) for sources determined to have a *de minimis* effect upon
human health and the environment.

### 3. Concentration or Quantity-Based Approach to De Minimis

Indeed, as mentioned in the white paper provided by the American Forest
and Paper Association ("AF&PA") regarding EPA's proposed MACT standards
for Plywood and Composite Wood Products, EPA makes applicability
determinations based on de minimis criteria on a regular basis. The
paper raises numerous examples such as exemptions from monitoring under
the Hazardous Organic NESHAP ("HON") for equipment leaks with
concentrations of volatiles below certain limits.[^76]

A recent example of the use of even more general "*de minimis*
authority" can be found in 67 Fed. Reg. 55129, wherein the EPA issued a
direct final rule to exempt " 'Noncommercial incineration of dead
animals, the on‑site incineration of resident animals for which no
consideration is received or commercial profit is realized, as
authorized in section 269.020.6, RSMo 2000.' The MDNR has submitted
emission inventory information which confirms that emissions from these
sources is minimal (for example, particulate emissions are approximately
one ton per year, or less), and that this exemption is not likely to
have an adverse impact on ambient air quality. No existing incinerators
in this source category are subject to the operating permit program, due
to their de minimis size."[^77] This is clearly an exemption based on
*de minimis* emissions.

### 4. Practical Application of EPA's Health Risk-Based De Minimis Authority

In some instances, there will be situations where the selection of a
MACT floor technology will result in the setting of an emission
limitation (and thus a resultant level of exposure) well below the
determined "safe" level. EPA should consider these situations and
provide, based upon a proper demonstration, and consistent with the CAA
and relevant caselaw, an exemption from the regulations when such MACT
controls will result in emission reductions of "trivial or no value."

There will likely also be situations wherein an evaluation of existing
sources would show that the emissions from those sources were not posing
an adverse impact on public health and the environment. Any reductions
achieved by the technology-based standard will merely reduce
insignificant exposures to an even more insignificant level. In short,
the implementation of the MACT standard will provide no benefit to human
health or the environment. In this instance, the agency should utilize
its administrative authority to provide exemptions based on the de
minimis benefit to human health and the environment.

Another scenario would be where implementation of the MACT standard
would result in significant emission reductions which will reduce
exposures from a potentially "significant" level of HAPs to a level
below what would be considered acceptable and with an adequate margin of
safety. EPA's regulatory approach should focus on those sources. Such
prioritization is not only sound public policy, but it will also provide
the greatest reduction in emissions of HAPs that may be impacting public
health and the environment.

## D. Economic and Cost Issues

### 1. EPA's own Analysis indicates that this Rule will Have Dire Economic Impacts on the Taconite Iron Ore Processing Industry

EPA's own Economic Impact Analysis of the proposed Taconite Iron Ore
NESHAP estimates that "the total capital costs of complying with the
proposed rule to be approximately \$47 million, and the total annualized
cost (including the costs of new capital equipment and new operation,
maintenance, monitoring, recordkeeping, and reporting activities) to be
\$7.09 million.[^78] Further, EPA acknowledges that along with prices
increases of taconite iron ore, 30 people could lose their jobs as a
result of this rulemaking. Moreover, EPA's own analysis states that 2 or
3 of the 8 remaining operations could be shuttered as a result of this
rule.[^79] [^80]

### 2. EPA's Economic Analysis Understates the Economic Impact of the Rulemaking and is Riddled with Errors

#### a. Executive Summary of the EIA

The executive summary appears to focus on only the best-case scenario.
The first inconsistency is stating a price increase of \$0.01 per metric
ton. This is based on a baseline price of \$55.13 per ton for taconite.
Table 2-12 and page 2-24 state that taconite prices range from \$25.51
to \$31.61. There is however no support in the document as to how this
baseline price was derived, particularly since this derived value
deviates from current actual prices by over 75%.

Another obvious yet confusing error in the analysis is that the
Market-Level Impacts (Table 4-1) show the quantity of domestic taconite
produced as 11.135 (10^6^ metric tons). However, Table 2-8, 2-11, and
2-12 all show domestic production at approximately 62.400 (10^6^ metric
tons). This is a huge discrepancy, and yet again, there is no
explanation.

The executive summary also asserts that a decrease of 3,000 metric tons
would be realized by the affected companies and that EPA estimates that
only 30 people would be laid-off as a result of the rule. Yes this
assertion is completely contradicted on page 4-8 and 4-9 when in
consecutive paragraphs it is stated, "...we conclude that possible 2 to
3 firms may close or sell..." and the next paragraph states that
domestic employment is projected to decline by only one employee.
Clearly there is no true analysis as to the employment impacts of this
proposed rulemaking.

#### b. Inaccuracies in the Introduction to the EIA

In another confusing part of the analysis, the introduction states there
are 13 iron ore companies that own 13 mining operations and 10
concentrating and pellet operations, yet the remainder of the report
mentions only 8 operations. is only familiar with 8 remaining operations
(and the idled LTV facility in Minnesota).

#### c. Industry Profile as Characterized by the EIA

Page 2-16 states that imports of foreign steel are projected to rise
10.1 million tons per year by 2003, thereby decreasing the need for
Michigan and Minnesota iron ore pellets. Page 2-24 continues along this
train of thought stating how domestic iron ore producers lowered prices
to domestic ore competitive with imported material. A comment on page
2-29 also follows this path in saying,"...each iron ore producer is
aware that it must reduce costs substantially to compete with foreign
producers." Therefore, how can a statement such as the one made on page
2-23 be made in good faith? They state that the taconite industry is
likely fairly concentrated and able to influence market prices.

The capacity and production number totals listed in Table 2-8 are off by
a margin of 12-18%. This is more than a rounding error. The numbers also
have an accuracy to the .01 place, so the rounding error should be no
greater than a tenth of a place.

#### d. Summary of Costs According to the EIA

The assumptions made for the cost analysis do not reflect the current
state of the economy. Capital costs are annualized over 25 years at 7%
interest. At this point, it could be difficult for a taconite operation
to procure a 25 year loan given the current economics of the industry.
The cost estimates for the individual taconite plants were based on cost
estimates from industry representatives, vendors, and the OAQPS control
cost manual. These estimates are widely variant from the estimates
provided by companies. In short, the EPA seems to believe that upgrades
on larger furnaces cost half as much as upgrades on smaller furnaces.

It is important to note that 98% of the costs are shown to be incurred
by only 4 facilities, with approximately 50% of the costs (as given)
incurred by two facilities. These facilities are already in a dire
economic situation. These added costs could push them over the edge and
into closure or bankruptcy.

#### e. Economic Impact Analysis

Page 4-1 asserts that no buyer or seller has market power and market
price is taken as a given when making production and consumption
choices. This is factually incorrect. In the iron ore market, price is
not taken as a given when the industry has such a large abundance of
foreign market products being pushed at customers at less than or equal
prices. The imported foreign products appear to be currently setting the
market price.

The analysis used elasticity numbers to gauge supply response. The logic
for choosing values is inconsistent. For example, domestic and foreign
supply elasticity values were midpoint values, but the import supply
elasticity value was the higher of the two, even though the lower number
represented the majority of the imports. This inconsistency was
unexplained.

Table 4-1 contains serious numeric flaws. Moreover, there was no
underlying support for the information in the table such as a breakdown
showing calculations and the source of the values in the table. Current
taconite prices and quantities do not reflect what is stated in prior
tables.

Section 4.2.3.1 examines conditions that contribute to capacity
reduction and closure. However, since no empirical work has been done on
this subject for taconite mines, the EPA used work prepared for the
steel industry. The majority of these studies were completed in the late
80's and early 90's. The one report done in 1998 stated that a change in
iron ore cost did not have a statistically significant impact on either
capacity or plant closures. It did not elaborate as to where the plant
would get iron ore nor what was considered significant. It also did not
take into account the increase in price for the four affected taconite
plants.

Even more confusing is that in one section of the EIA, the agency
concludes that this regulation alone is unlikely to lead to mine
closure, but on page 4-8 the report clearly states that its possible 2
to 3 firms may close or sell some or all of their operations. The only
consistent statement in the report is that the proposed rule will add to
existing financial stresses in the industry.

The employment impacts are inconsistently reported, and overwhelmingly
understated. Based on the assumption that taconite mining is a highly
capital intensive industry rather than labor intensive, lost domestic
production is not expected to lead to substantial layoffs. However,
because the industry is so capital intensive, funds are traditionally
diverted from manpower rather than capital expenditures to keep the
facilities operational. The employment numbers also take credit for
additional manpower needed for the MRR activities. The majority of these
activities will be computer controlled and recorded, adding no
additional manpower needs and may lead to additional areas for cuts in
the workforce by reducing the current monitoring workload. However, the
impact on indirect employment will be severe if 2 or 3 mines close.

It also appears that Table 4-1 (Market-Level Impacts of the Taconite
NESHAP, 2000) is inaccurate. We would estimate that actual industry
production in 2000 (no rounding) to be 55.07 (10^6^ metric tons). The
industry production cost should be \$1,677,400,000. Annualized costs in
Table 3-3 should be \$7,089,000

## E. Background Information on the Taconite Iron Ore Processing Industry

We have recently been reviewing some of the data that was used for not
only establishing the Taconite Ore Processing Industry as a Source
Category, but also for evaluating emissions and establishing the floor.
Once we have quality assured this data, we will provide it to EPA so
that the necessary corrections can be made.

# [IV. R]{.smallcaps}ecommendations

## A. Split the Taconite Ore Processing Category into Two Source Categories

The current source category called "Taconite Iron Ore Processing" should
be split into two source categories consistent with the two very
separate types of operations conducted in the Taconite industry.
Specifically, ore crushing and handling (including ore dryers) and
finished pellet handling operations should be a separate source category
from the indurating furnaces. Also, as discussed by EPA in the preamble
to the proposed rule, for some of the mining companies, these processes
are not even co-located with the indurating furnace operations. The ore
crushing and handling and finished pellet handling operations are truly
crushing and handling operations and are distinct in engineering, form,
and operation of indurating furnaces**[.]{.smallcaps}** They are
substantially different sources with different available and feasible
control technologies.

The CAA clearly gives EPA broad discretion to establish source
categories and subcategories. Specifically, Section 112(c)(1) of the CAA
states:

> the Administrator shall publish, and shall from time to time, but no
> less often than every 8 years, revise, if appropriate, in response to
> public comment or new information, a list of all categories and
> subcategories of major sources and area sources (listed under
> paragraph (3)) of the air pollutants listed pursuant to subsection
> (b). To the extent practicable, the categories and subcategories
> listed under this subsection shall be consistent with the list of
> source categories established pursuant to section 111 and part C.
> Nothing in the preceding sentence limits the Administrator\'s
> authority to establish subcategories under this section, as
> appropriate.

One of the first actions EPA undertook in the BSCP and CC proposal was
to split out BSCP and CC from the initial broader listing of a clay
products manufacturing source category. This appears to be appropriate
and well within EPA's authority under the CAA. Section 112(c) of the CAA
grants the Administrator broad discretion for establishing source
categories and subcategories.[^81] Specifically, section 112(c) provides
that the Administrator:

shall publish, and shall from time to time, but no less often than every
8 years, revise, if appropriate, in response to public comment or new
information, a list of all categories and subcategories of major sources
and area sources (listed under paragraph (3)) of the air pollutants
listed pursuant to subsection (b). To the extent practicable, the
categories and subcategories listed under this subsection shall be
consistent with the list of source categories established pursuant to
section 111 and part C. Nothing in the preceding sentence limits the
Administrator\'s authority to establish subcategories under this
section, as appropriate. 42 U.S.C. § 7412(c)(1).

In order to best meet the purpose and intent of Congress and to achieve
the goals of the CAA, it is best to tailor the scope and breadth of the
source category to the industry. EPA has already done this in several
instances including the recently proposed NESHAP for Brick and
Structural Clay Products ("BSCP") and Clay Ceramics ("CC")
manufacturing. As with the BSCP and CC MACT standards, this approach is
particularly supportable when the original source categories were
broadly defined and, by EPA's methodology for establishing NESHAPs
today, the original category would cover multiple "affected sources". As
EPA recently indicated, the agency believes that they have tremendous
discretion to define what constitutes an "affected source" under the
program.[^82]

As with the BSCP category, the Taconite Iron Ore Processing source
category should be split into two source categories: thermal operations
(including the indurating furnaces) and the material handling
operations. Then, upon review of recent emission data, EPA will find
that none of the material handling operations are in and of themselves
"major sources" of HAP under the CAA. Since the material handling
operations are co-located with major sources of HAPs, i.e., the
indurating furnaces, they should be handled analogously to the recently
proposed decision not to regulate Chlorine and Hydrochloric Acid
Emissions from Chlorine Production under a NESHAP rulemaking.[^83] In
that federal register notice, EPA noted

> None of the 20 chlor-alkali plants are major in and of themselves, but
> are major due to collocation. That is, they are part of a larger
> contiguous establishment that is a major source. These larger
> establishments include organic chemical manufacturers, polymer and
> resin producers, and pulp and paper mills, all of which are already
> subject to one or more NESHAP.[^84]

On that basis alone, EPA could have elected to not regulate the
chlor-alkali plants since they are not in and of themselves major
sources. Similarly, EPA could choose not to regulate Taconite Iron Ore
material handling operations. In short, as with the other delistings the
Administrator has unilaterally undertaken, Taconite Iron Ore Material
Handling Operations can be delisted.[^85]

In the Chlorine Production rules though, EPA went a step further and
stated that they could delist the category since it met the criteria of
Section 112(d)(4).[^86]

> We are proposing not to regulate chlorine and HCl emissions from
> chlorine production processes. Under the authority of section
> 112(d)(4), we have determined that no further control is necessary
> because chlorine and HCl are ''health threshold pollutants,'' and
> chlorine and HCl levels emitted from chlorine production processes are
> below their threshold values within an ample margin of safety.
> Further, due to the fact that these two pollutants are the only HAP
> emitted in significant quantities from chlorine production plants, we
> are proposing not to develop any NESHAP for the Chlorine Production
> source category, with the exception of a NESHAP for mercury emissions
> from mercury cell chlor-alkali plants.

## B. EPA Should Carefully Review and then Grant the Delisting Petition 

Following the submittal of this comment, the members of plan to continue
to develop a technically complete and scientifically sound petition to
delist all Taconite Iron Ore operations from regulation under Section
112(d). Based on preliminary data, we believe we can make a credible
scientific demonstration that these operations meet the criteria to be
delisted under Section 112(c)(9).

## C. Include Alternative Risk-Based or De Minimis Approaches for this NESHAP

As described in detail above, EPA has proposed numerous NESHAP rules
lately which include extensive discussions on alternative approaches to
implementing Section 112 of the CAA. Although the proposed Taconite Iron
Ore Processing NESHAP contained no such discussion, many of the proposed
alternative approaches could well be applied to these operations.

Although we are confident that we can present a case for delisting all
of the Taconite operations, we remain concerned about the timing of
processing and granting such a petition. Therefore, we should have the
opportunity to avail ourselves of the alternative approaches found in
the aforementioned proposed NESHAPs.[^87] Again, based on our
preliminary investigation, our operations would meet the criteria of
having an ambient impact which imposed far less than a lifetime excess
cancer risk of one in one million, and, based on EPA's own Reference
Concentrations (which represent virtually safe doses), the ambient
impact of the emissions easily provides an "ample margin" or safety.

Moreover, in terms of evaluating the impact of Taconite Iron Ore
Processing operations, by comparison to the other source categories
being evaluated (wood and composite wood materials, boilers, surface
coating operations, etc.) this industry is miniscule with only 8
operations across the country

# V. CONCLUSION

The proposed NESHAP for Taconite Iron Ore Processing will have a serious
and dramatic economic impact on taconite iron ore processing operations,
yet will result in little environmental or public health benefit. These
rules should be revised so as to better balance protection of public
health and welfare with the costs of achieving such protection.

Overall, based on preliminary analysis, the operations under this source
category meet the criteria to be de-listed under the provisions of
Section 112(c)(9) of the Clean Air and we fully intend to submit a
petition to de-list this source category, along with the appropriate
supporting documentation, by June 30, 2003.

However, the EPA has one year to review the petition. Since the Taconite
Iron Ore NESHAP is scheduled to be finalized by August 2003, that means
the industry will lose 10 months of preparation for designing,
engineering, budgeting, installing, testing, and implementing the
necessary steps to comply with the standard in the event the petition is
not processed or approved in time. Thus, in the interim, in the event
the delisting petition is unable to proceed through the necessary
administrative processes in a timely fashion, we would like to be able
to utilize other provisions of the Act and EPA's implementing authority
to mitigate the impact of this rule on the industry. For example, we
think the Taconite Iron Ore source category should be split into two
source categories: indurating furnaces and material handling operations.
The emissions from the material handling operations are so low, and
present such a low risk, EPA could easily determine that these
operations either meet the criteria of Section 112(c)(9) and delist the
category on the Agency's own motion, or since these operations have such
low emissions and such minimal ambient impact, EPA could also address
them through the Agency's inherent *de minimis* authority. Such an
approach could either be based on *de minimis* emissions or *de minimis*
risk. In addition, we are also interested in the use of Section
112(d)(4) for purposes of establishing MACT requirements (and
effectively accelerating the application of the residual risk provisions
contained in Section 112(f)).

As for immediate action, we request that the Taconite Iron Ore
Processing source category be split into two source categories which
more accurately reflect the two diverse types of operations found at
taconite iron ore processing operations: thermal indurating furnace
operations, and physical material handling operations. This proposal to
split this source category into two source categories is well within
EPA's discretion and is consistent both with the clear language of the
Clean Air Act ("CAA") and the intent of Congress. Moreover, this
proposal to split the original source category into two categories is
consistent with EPA's concept of defining and regulating the "affected
sources" in the current proposed Taconite Iron Ore NESHAP. Additional
discussion and support for this proposition is provided in the attached
comments.

As discussed in our cover letter, the domestic iron and steel industry
is in dire economic straits right now. U.S. Representative John Murtha's
editorial in the January 27, 2003, Washington Times, was particularly
timely and we hope, enlightening to the Agency. (See, January 27, 2003
Washington Times, "Essential Steel", by U.S. Representative John Murtha,
http://www.washtimes.com/op‑ed/20030127‑18935790.htm.)

As discussed above, using EPA's own Economic Impact Analysis, the result
of the implementation of this NESHAP could be devastating to at least
25% of the industry and their communities. This, in combination with
U.S. Representative Murtha's comments on the importance of the iron and
steel industry to national security, should help explain why the
industry is so concerned with the proposed rule.

Again, we urge the upper levels of management of EPA and OMB take a
close look at this proposed rulemaking and evaluate the costs of the
rulemaking and the nominal benefit to the environment of controlling
what EPA itself has characterized as "trace quantities" of metal HAPs
contained in particulate matter emitted from the taconite iron ore
industry. There are far better ways to spend limited resources in this
country and as leaders, we are relying on your judgment to prioritize
the risks posed by these operations and consider the lack of
environmental benefit that will result at great cost to the industry.

[^1]: 42 U.S.C.A. §§7401 *et. seq*.

[^2]: National Emission Standards for Hazardous Air Pollutants (NESHAP)
    for Taconite Iron Ore Processing Plants

    Background Information for Proposed Standards, EPA 453/R-02-015
    December 2002, page 3-11.

[^3]: Ibid.

[^4]: 67 Fed. Reg. 44713, July 3, 2002, National Emission Standards for
    Hazardous Air Pollutants: Chlorine and Hydrochloric Acid Emissions
    From Chlorine Production; proposed decision not to regulate.

[^5]: See 67 Fed. Reg. 47894, National Emission Standards for Hazardous
    Air Pollutants for Brick and Structural Clay Products Manufacturing;
    and National Emission Standards for Hazardous Air Pollutants for
    Clay Ceramics Manufacturing; Proposed Rule July, 22, 2002, See also,
    67 Fed. Reg. 77830, National Emission Standards for Hazardous Air
    Pollutants for Stationary Reciprocating Internal Combustion Engines,
    Proposed Rule, December 19, 2002. See also, 67 Fed. Reg. 78612
    National Emission Standards for Hazardous Air Pollutants: Surface
    Coating of Automobiles and Light-Duty Trucks, Proposed Rule,
    December 24, 2002. See also, 68 Fed. Reg. 1276, National Emission
    Standards for Hazardous Air Pollutants: Plywood and Composite Wood
    Products, Proposed Rule, January 9, 2003. See also, 68 Fed. Reg.
    1660, National Emission Standards for Hazardous Air Pollutants for
    Industrial/ Commercial/Institutional Boilers and Process Heaters,
    Proposed Rule, January 13, 2003.

[^6]: Since 98% of the emissions are manganese, and manganese is a
    non-carcinogen, it clearly has a health threshold and should be
    eligible for being treated under the provisions of section
    112(d)(4).

[^7]: See National Lime v. EPA, 233 F.3d 625, 51 ERC 1737 (D.C. Cir.
    2000). See also, Cement Kiln Recycling Coalition, 255 F.3d 855, 52
    ERC 1865 (D.C. Cir. 2001).

[^8]: 67 Fed. Reg. 16614, April 5, 2002.

[^9]:

[^10]: *NRDC v. EPA*, 194 F.3d 130, (D.C. Circuit, October 29, 1999).

[^11]: General Provisions, Background Information Document,
    EPA-450/3-91-019b, February 1994, page 2-49.

[^12]: General Provisions, Background Information Document,
    EPA-450/3-91-019b, February 1994, page 2-136.

[^13]: 67 Fed. Reg. 47894 at 47904, National Emission Standards for
    Hazardous Air Pollutants for Brick and Structural Clay Products
    Manufacturing; and National Emission Standards for Hazardous Air
    Pollutants for Clay Ceramics Manufacturing; Proposed Rule, July, 22,
    2002. See also, 67 Fed. Reg. 77830, National Emission Standards for
    Hazardous Air Pollutants for Stationary Reciprocating Internal
    Combustion Engines, Proposed Rule, December 19, 2002; 67 Fed. Reg.
    78612 National Emission Standards for Hazardous Air Pollutants:
    Surface Coating of Automobiles and Light-Duty Trucks, Proposed Rule,
    December 24, 2002; 68 Fed. Reg. 1276, National Emission Standards
    for Hazardous Air Pollutants: Plywood and Composite Wood Products,
    Proposed Rule, January 9, 2003; 68 Fed. Reg. 1660, National Emission
    Standards for Hazardous Air Pollutants for
    Industrial/Commercial/Institutional Boilers and Process Heaters,
    Proposed Rule, January 13, 2003

[^14]: 67 Fed. Reg. 47894, at National Emission Standards for Hazardous
    Air Pollutants for Brick and Structural Clay Products Manufacturing;
    and National Emission Standards for Hazardous Air Pollutants for
    Clay Ceramics Manufacturing; Proposed Rule, July, 22, 2002. See
    also, 67 Fed. Reg. 77830, National Emission Standards for Hazardous
    Air Pollutants for Stationary Reciprocating Internal Combustion
    Engines, Proposed Rule, December 19, 2002. See also, 67 Fed. Reg.
    78612 National Emission Standards for Hazardous Air Pollutants:
    Surface Coating of Automobiles and Light-Duty Trucks, Proposed Rule,
    December 24, 2002. See also, 68 Fed. Reg. 1276, National Emission
    Standards for Hazardous Air Pollutants: Plywood and Composite Wood
    Products, Proposed Rule, January 9, 2003. See also, 68 Fed. Reg.
    1660, National Emission Standards for Hazardous Air Pollutants for
    Industrial/ Commercial/Institutional Boilers and Process Heaters,
    Proposed Rule, January 13, 2003.

[^15]: 67 Fed. Reg. 47894, at 47904 (July 22, 2002)

[^16]: 67 Fed. Reg. 47894 at 47904, National Emission Standards for
    Hazardous Air Pollutants for Brick and Structural Clay Products
    Manufacturing; and National Emission Standards for Hazardous Air
    Pollutants for Clay Ceramics Manufacturing; Proposed Rule, July, 22,
    2002. See also, 67 Fed. Reg. 77830, National Emission Standards for
    Hazardous Air Pollutants for Stationary Reciprocating Internal
    Combustion Engines, Proposed Rule, December 19, 2002; 67 Fed. Reg.
    78612 National Emission Standards for Hazardous Air Pollutants:
    Surface Coating of Automobiles and Light-Duty Trucks, Proposed Rule,
    December 24, 2002; 68 Fed. Reg. 1276, National Emission Standards
    for Hazardous Air Pollutants: Plywood and Composite Wood Products,
    Proposed Rule, January 9, 2003; 68 Fed. Reg. 1660, National Emission
    Standards for Hazardous Air Pollutants for
    Industrial/Commercial/Institutional Boilers and Process Heaters,
    Proposed Rule, January 13, 2003.

[^17]: 67 Fed. Reg. 47894, at 47904 (July 22, 2002).

[^18]: Public Law 101-549, November 15, 1990, 104 Stat. 2399. Codified
    under the Clean Air Act, 42 U.S.C. §§ 7401 -- 7601q, as amended.

[^19]: 42 U.S.C.A. §§ 7412(b)

[^20]: section 112(e) of the CAA provides the schedule for promulgating
    emissions standards for the listed categories.

[^21]: Several earlier versions of the various bills that were proposed
    used the terminology "maximum achievable control technology emission
    limitation" (hence "MACT"). That terminology was changed to the more
    formal "maximum degree of reduction in emissions that is deemed
    achievable" just prior to enactment. (Section 112(g) is the only
    section of the Act that retains the phrase "maximum achievable
    control technology". Apparently the language of that section was
    added late in the legislative process after all of the other
    occurrences of MACT had already been modified to reflect the more
    formal terminology.)

[^22]: The 1990 CAA specifically preserved the NESHAP standards
    developed under the prior version of the CAA and codified under 40
    C.F.R. Part 61.

[^23]: Senate Legislative History, S. Rep. No. 231, 100th Cong., 1st
    Sess. 220 ( 1990)

[^24]: House of Representatives Legislative History, H.R. Conf. Rep. No.
    952, at 140-43.

[^25]: The Act also provides that the Administrator may establish lesser
    quantities for the major source threshold based on the potency of
    the substance, the persistence, bioaccumulation characteristics, or
    other relevant factors. 42 U.S.C. §7412(a)(1).

[^26]: 56 Fed. Reg. 28548, June 21, 1991.

[^27]: 57 Fed. Reg. 31576, July 16, 1992.

[^28]: 57 Fed. Reg. 31576, July 16, 1992.

[^29]: section 112(e) of the CAA provides the schedule for promulgating
    emissions standards for the listed categories.

[^30]: Several earlier versions of the various bills that were proposed
    used the terminology "maximum achievable control technology emission
    limitation" (hence "MACT"). That terminology was changed to the more
    formal "maximum degree of reduction in emissions that is deemed
    achievable" just prior to enactment. (Section 112(g) is the only
    section of the Act that retains the phrase "maximum achievable
    control technology". Apparently the language of that section was
    added late in the legislative process after all of the other
    occurrences of MACT had already been modified to reflect the more
    formal terminology.)

[^31]: 42 U.S.C. §7401(d)(3).

[^32]: National Emission Standards for Hazardous Air Pollutants;
    Proposed Standards for Hazardous Air Pollutants From Chemical
    Recovery Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone
    Semichemical Pulp Mills; Proposed Rule, 63 Fed. Reg. 18784, April
    15, 1998.

[^33]: 54 Federal Register 38044, September 14, 1989.

[^34]: *NRDC v Thomas*, 824 F.2d 1146, (D.C. Circuit, En Banc, July
    1987)

[^35]: 42 U.S.C. §7412(k)

[^36]: 42 U.S.C. §7412(B)

[^37]: 42 U.S.C. §7412(k)(5) states: "(5) REPORT.---The Administrator
    shall report to the Congress at intervals not later than 8 and 12
    years after the date of enactment of the Clean Air Act Amendments of
    1990 on actions taken under this subsection and other parts of this
    Act to reduce the risk to public health posed by the release of
    hazardous air pollutants from area sources. The reports shall also
    identify specific metropolitan areas that continue to experience
    high risks to public health as the result of emissions from area
    sources."

[^38]: What constitutes an "acceptable" level of risk is spelled out by
    various provisions in the CAA and the caselaw as described later in
    this paper.

[^39]: See footnote 20 of these comments for citations.

[^40]: 67 Fed. Reg. 47894 at 47904, National Emission Standards for
    Hazardous Air Pollutants for Brick and Structural Clay Products
    Manufacturing; and National Emission Standards for Hazardous Air
    Pollutants for Clay Ceramics Manufacturing; Proposed Rule, July, 22,
    2002. See also, 67 Fed. Reg. 77830, National Emission Standards for
    Hazardous Air Pollutants for Stationary Reciprocating Internal
    Combustion Engines, Proposed Rule, December 19, 2002; 67 Fed. Reg.
    78612 National Emission Standards for Hazardous Air Pollutants:
    Surface Coating of Automobiles and Light-Duty Trucks, Proposed Rule,
    December 24, 2002; 68 Fed. Reg. 1276, National Emission Standards
    for Hazardous Air Pollutants: Plywood and Composite Wood Products,
    Proposed Rule, January 9, 2003; 68 Fed. Reg. 1660, National Emission
    Standards for Hazardous Air Pollutants for
    Industrial/Commercial/Institutional Boilers and Process Heaters,
    Proposed Rule, January 13, 2003.

[^41]: 67 Fed. Reg. 47894, at 47904 (July 22, 2002).

[^42]: Public Law 101-549, November 15, 1990, 104 Stat. 2399. Codified
    under the Clean Air Act, 42 U.S.C. §§ 7401 -- 7601q, as amended.

[^43]: 42 U.S.C.A. §§ 7412(b).

[^44]: § 112(e) of the CAA provides the schedule for promulgating
    emissions standards for the listed categories.

[^45]: Several earlier versions of the various bills that were proposed
    used the terminology "maximum achievable control technology emission
    limitation" (hence "MACT"). That terminology was changed to the more
    formal "maximum degree of reduction in emissions that is deemed
    achievable" just prior to enactment. (§ 112(g) is the only section
    of the Act that retains the phrase "maximum achievable control
    technology". Apparently the language of that section was added late
    in the legislative process after all of the other occurrences of
    MACT had already been modified to reflect the more formal
    terminology.)

[^46]: National Emission Standards for Hazardous Air Pollutants;
    Proposed Standards for Hazardous Air Pollutants From Chemical
    Recovery Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone
    Semichemical Pulp Mills; Proposed Rule, 63 Fed. Reg. 18784, April
    15, 1998.

[^47]: Id. at 47715.

[^48]: Id.

[^49]: 67 Fed. Reg. 47894, National Emission Standards for Hazardous Air
    Pollutants for Brick and Structural Clay Products Manufacturing; and
    National Emission Standards for Hazardous Air Pollutants for Clay
    Ceramics Manufacturing; Proposed Rule July, 22, 2002.

[^50]: 67 Fed. Reg. 78612 National Emission Standards for Hazardous Air
    Pollutants: Surface Coating of Automobiles and Light-Duty Trucks,
    Proposed Rule, December 24, 2002

[^51]: 68 Fed. Reg. 1660, National Emission Standards for Hazardous Air
    Pollutants for Industrial/ Commercial/Institutional Boilers and
    Process Heaters, Proposed Rule, January 13, 2003

[^52]: 68 Fed. Reg. 1276, National Emission Standards for Hazardous Air
    Pollutants: Plywood and Composite Wood Products, Proposed Rule,
    January 9, 2003

[^53]: 67 Fed. Reg. 77830, National Emission Standards for Hazardous Air
    Pollutants for Stationary Reciprocating Internal Combustion Engines,
    Proposed Rule, December 19, 2002

[^54]: See 63 FR 18754, 18765-66 (April 15, 1998) (Pulp and Paper
    Combustion Sources Proposed NESHAP).

[^55]: 42 U.S.C. §7412(f)(2).

[^56]: "Methods for Derivation of Inhalation Reference Concentrations
    and Applications of Inhalation Dosimetry." EPA-600/8-90-066F, Office
    of Research and Development, USEPA, October 1994

[^57]: "Supplementary Guidance for Conducting Health Risk Assessment of
    Chemical Mixtures. Risk Assessment Forum Technical Panel,"
    EPA/630/R-00/002. USEPA, August 2000.
    http://www.epa.gov/nceawww1/pdfs/chem mix/chem mix 08 2001.pdf.

[^58]: "A Tiered Modeling Approach for Assessing the Risks due to
    Sources of Hazardous Air Pollutants." EPA-450/4-92-001. David E.
    Guinnup, Office of Air Quality Planning and Standards, USEPA, March
    1992.

[^59]: "Draft Revised Guidelines for Carcinogen Risk Assessment."
    NCEA-F-0644. USEPA, Risk Assessment Forum, July 1999. pp 3- 9ff.
    http://www.epa.gov/ncea/raf/pdfs/cancer_gls.pdf.

[^60]: EPA is evaluating formaldehyde, not only for its unit risk
    factor, but also to determine if it is a threshold carcinogen.

[^61]: 67 Fed. Reg. 77830

[^62]: 67 Fed. Reg. 77830 at 77850

[^63]: 67 Fed. Reg. 77830 at 77850

[^64]: Ibid.

[^65]: 42 U.S.C. § 7412(f)(2)(A).

[^66]: *Alabama Power Co. v. Costle* 636 F.2d 323 (D.C. Cir. 1979)

[^67]: *Alabama Power Co. v. Costle* 636 F.2d 323 at 361 (D.C. Cir.,
    1979)

[^68]: The *Alabama Power* Court went on to exclude situations where the
    Agency decides to adopt an exemption merely because the benefits are
    exceeded by the costs. Specifically, the Court stated: "That implied
    authority is not available for a situation where the regulatory
    function does provide benefits, in the sense of furthering the
    regulatory objectives, but the agency concludes that the
    acknowledged benefits are exceeded by the costs. For such a
    situation any implied authority to make cost-benefit decisions must
    be based not on a general doctrine but on a fair reading of the
    specific statute, its aims and legislative history. *Alabama Power
    Co. v. Costle* 636 F.2d 323 at 361 (D.C. Cir., 1979). We are not
    arguing that there should be exemptions based on cost, rather we are
    arguing that EPA can structure the MACT rules such that de minimis
    levels of emissions or de minimis levels of risks to public health
    (as defined by the act, e.g., ample margin of safety) not be subject
    to the technology based standards developed under section 112(d)(3).

[^69]: *Alabama Power Co. v. Costle* 636 F.2d 323 at 361 (D.C. Cir.,
    1979)

[^70]: The "MACT floor" is a term used by EPA to describe the statutory
    criteria for establishing the level of control technology. Thus the
    "MACT floor" is defined, for new sources, as "the emissions control
    \... achieved in practice by the best controlled similar unit\". For
    existing sources, the "MACT floor" is defined as \"the average
    emissions limitation achieved by the best performing 12 percent of
    units in the category\". 42 U.S.C. § 7412(d)(2). The term "MACT"
    itself is generally considered to be an acronym reflecting the
    "maximum degree of reduction in emissions of the hazardous air
    pollutants subject to this section (including a prohibition on such
    emissions, where achievable) that the Administrator, taking into
    consideration the cost of achieving such emission reduction, and any
    non-air quality health and environmental impacts and energy
    requirements." 42 U.S.C. § 7412(d)(2).

[^71]: *National Lime Association v. EPA*, 233 F.3d 625 (D.C. Cir.,
    2000)

[^72]: Where the concept of risk is defined by the Act, e.g., by
    providing for an ample margin of safety or individual excess cancer
    risks of not more than one in one million.

[^73]: 68 Fed. Reg. 1276 at 1301, January 9, 2003.

[^74]: Section 112(f)(2)(A) and (B) requires the Administrator to
    "promulgate standards for such category or subcategory if
    promulgation of such standards is required in order to provide an
    ample margin of safety to protect public health in accordance with
    this section (as in effect before the date of enactment of the Clean
    Air Act Amendments of 1990) or to prevent, taking into consideration
    costs, energy, safety, and other relevant factors, an adverse
    environmental effect. Emission standards promulgated under this
    subsection shall provide an ample margin of safety to protect public
    health in accordance with this section (as in effect before the date
    of enactment of the Clean Air Act Amendments of 1990), unless the
    Administrator determines that a more stringent standard is necessary
    to prevent, taking into consideration costs, energy, safety, and
    other relevant factors, an adverse environmental effect. If
    standards promulgated pursuant to subsection (d) and applicable to a
    category or subcategory of sources emitting a pollutant (or
    pollutants) classified as a known, probable or possible human
    carcinogen do not reduce lifetime excess cancer risks to the
    individual most exposed to emissions from a source in the category
    or subcategory to less than one in one million, the Administrator
    shall promulgate standards under this subsection for such source
    category. (B) Nothing in subparagraph (A) or in any other provision
    of this section shall be construed as affecting, or applying to the
    Administrator\'s interpretation of this section, as in effect before
    the date of enactment of the Clean Air Act Amendments of 1990 and
    set forth in the Federal Register of September 14, 1989 (54 Federal
    Register 38044).

[^75]: "With respect to pollutants for which a health threshold has been
    established, the Administrator may consider such threshold level,
    with an ample margin of safety, when establishing emission standards
    under this subsection." 42 U.S.C. § 7401(d)(4).

[^76]: See NESHAP standards under 40 C.F.R. Subparts F, G, and H.

[^77]: 67 Fed. Reg. 55129 at 55130, August 28, 2002.

[^78]: Economic Impact Analysis of the proposed Taconite Iron Ore
    NESHAP, FINAL REPORT, Environmental Protection Planning And
    Standards November 2002, EPA-452/R-02-013.

[^79]: Ibid.

[^80]: After concluding that this proposed rule could result in the
    closure of 2 or 3 operations, it is unclear how EPA actually arrived
    at the conclusion that only 1 employee would be laid off. We believe
    this assessment is wholly inaccurate and dramatically undercounts
    the number of jobs that would be lost if these operations are shut
    down. Not only would there be a direct loss of mining jobs, but many
    jobs and businesses that have grown up around the mines and are
    basically supported by the economy generated by the mines. These
    businesses would undoubtedly suffer severe and irreparable harm if
    this rule is promulgated in its current form. These costs are
    understated in the economic analysis.

[^81]: See the final revisions to the general provisions of 40 C.F.R.
    Part 63, 67 Fed. Reg. 16582, April 5, 2002.

[^82]: See the final revisions to the general provisions of 40 C.F.R.
    Part 63, 67 Fed. Reg. 16582, April 5, 2002.

[^83]: 67 Fed. Reg. 44713, July 3, 2002.

[^84]: Ibid.

[^85]: EPA has delisted numerous compounds on their own motion. See
    <http://www.epa.gov/ttn/atw/socatlst/socatpg.html> for a description
    of the appropriate federal register notices.

[^86]: Section 112(d)(4) of the Clean Air Act states: "(4) Health
    threshold. With respect to pollutants for which a health threshold
    has been established, the Administrator may consider such threshold
    level, with an ample margin of safety, when establishing emission
    standards under this subsection." 42 U.S.C. §7412(d)(4).

[^87]: See 67 Fed. Reg. 47894, National Emission Standards for Hazardous
    Air Pollutants for Brick and Structural Clay Products Manufacturing;
    and National Emission Standards for Hazardous Air Pollutants for
    Clay Ceramics Manufacturing; Proposed Rule July, 22, 2002, See also,
    67 Fed. Reg. 77830, National Emission Standards for Hazardous Air
    Pollutants for Stationary Reciprocating Internal Combustion Engines,
    Proposed Rule, December 19, 2002. See also, 67 Fed. Reg. 78612
    National Emission Standards for Hazardous Air Pollutants: Surface
    Coating of Automobiles and Light-Duty Trucks, Proposed Rule,
    December 24, 2002. See also, 68 Fed. Reg. 1276, National Emission
    Standards for Hazardous Air Pollutants: Plywood and Composite Wood
    Products, Proposed Rule, January 9, 2003. See also, 68 Fed. Reg.
    1660, National Emission Standards for Hazardous Air Pollutants for
    Industrial/ Commercial/Institutional Boilers and Process Heaters,
    Proposed Rule, January 13, 2003.