federal register

24211

Friday

May 2, 1997

Part III

Environmental

Protection Agency

40 CFR Part 60, et al.

Revised Technical Standards for

Hazardous Waste Combustion Facilities;

Proposed Rule
24212 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 60, 63, 260, 261, 264, 265,

266, 270, and 271

[FRL–5818–9]

Revised Technical Standards for

Hazardous Waste Combustion

Facilities

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Notice of data availability and

request for comments.

SUMMARY: This document is a notice of

availability and invitation for comment

on the following information pertaining

to the proposed revised standards for

hazardous waste combustors (61 FR

17358 (April 19, 1996)): Report on the

status of setting national emission

standards for hazardous air pollutants

(NESHAPS) based on the revised

emissions database; Report on the

selection of pollutants and source

categories, including area and major

sources; report on the status of various

implementation issues, including

compliance dates, compliance

requirements, performance testing, and

notification and reporting requirements;

and report on the status of permit

requirements, including waste

minimization incentives.

DATES: Written comments must be

submitted by June 2, 1997.

ADDRESSES: Commenters must send an

original and two copies of their

comments referencing docket number

F–97–CS4A–FFFFF to: RCRA Docket

Information Center, Office of Solid

Waste (5305G), U.S. Environmental

Protection Agency Headquarters (EPA,

HQ), 401 M Street, SW., Washington,

DC 20460. Deliveries of comments

should be made to the Arlington,

Virginia address listed below.

Comments may also be submitted

electronically through the Internet to:

rcra-docket@epamail.epa.gov.

Comments in electronic format should

also be identified by the docket number

F–97–CS4A–FFFFF. All electronic

comments must be submitted as an

ASCII file avoiding the use of special

characters and any form of encryption.

For other information regarding

submitting comments electronically or

viewing the comments received or

supporting information, please refer to

the proposed rule (61 FR 17358 (April

19, 1996)).

Commenters should not submit

electronically any confidential business

information (CBI). An original and two

copies of the CBI must be submitted

under separate cover to: RCRA CBI

Document Control Officer, Office of

Solid Waste (5305W), U.S. EPA, 401 M

Street, SW., Washington, DC 20460.

Public comments and supporting

materials are available for viewing in

the RCRA Information Center (RIC),

located at Crystal Gateway One, 1235

Jefferson Davis Highway, First Floor,

Arlington, Virginia. The RIC is open

from 9 a.m. to 4 p.m., Monday through

Friday, except for Federal holidays. To

review docket materials, the public

must make an appointment by calling

703–603–9230. The public may copy a

maximum of 100 pages from any

regulatory docket at no charge.

Additional copies cost $0.15 per page.

FOR FURTHER INFORMATION CONTACT: For

general information, contact the RCRA

Hotline at 1–800–424–9346 or TDD 1–

800–553–7672 (hearing impaired). In

the Washington metropolitan area, call

703–412–9810 or TDD 703–412–3323.

The RCRA Hotline is open Monday–

Friday, 9 a.m. to 6 p.m., Eastern

Standard Time. The RCRA Hotline can

also provide directions on how to access

electronically some of the documents

and data referred to in this notice via

EPA’s Cleanup Information Bulletin

Board System (CLU-IN). The CLU-IN

modem access phone number is 301–

589–8366, or Telnet to clu-in.epa.gov for

Internet access. The files posted on

CLU-IN are in Portable Document

Format (PDF) and can be viewed and

printed using Acrobat Reader.

For more detailed information on

specific aspects of this notice, contact

Larry Denyer, Office of Solid Waste

(5302W), U.S. Environmental Protection

Agency, 401 M Street, SW., Washington,

DC 20460, 703–308–8770, e-mail

address: denyer.larry@epamail.epa.gov.

SUPPLEMENTARY INFORMATION:

The Agency specifically solicits

comment on the following documents:

(1) Draft Technical Support Document

for HWC MACT Standards (NODA),

Volume I: MACT Evaluations Based on

Revised Database, April 1997.

(2) Draft Technical Support Document

for HWC MACT Standards (NODA),

Volume II: Evaluation of CO/HC and

DRE Database, April 1997.

(3) Draft Technical Support Document

for HWC MACT Standards (NODA),

Volume III: Evaluation of Metals

Emissions Database to Investigate

Extrapolation and Interpolation Issues,

April 1997.

In preparing this notice, the Agency

considered comments on the proposed

rule, including those listed below. EPA

is soliciting responsive comments

regarding certain data and information

presented in these comments:

(1) Cement Kiln Recycling Coalition

(2) Chemical Manufacturers

Association

(3) Coalition for Responsible Waste

Incineration

(4) Don Clay Associates

(5) The Dow Chemical Company

(6) Environmental Technology

Council

(7) Holnam Inc.

(8) Lafarge Corporation

(9) Molten Metal Technology, Inc.

(10) The Natural Resources Defense

Council, Inc.

(11) Rollins Environmental Services,

Inc.

(12) Safety-Kleen Corp.

(13) Texas Natural Resource

Conservation Commission

(14) vonRoll/WTI

Readers should note that only

comments about new information

discussed in this notice will be

considered by the Agency. Issues related

solely to the April 19, 1996 proposed

rule and other subsequent notices that

are not directly affected by the

documents or data referenced in today’s

Notice of Data Availability are not open

for further comment.

Glossary of Acronyms

acfm—Actual Cubic Feet per Minute

ACI—Activated Carbon Injection

APCD—Air Pollution Control Device

BIF—Boiler and Industrial Furnace

BTF—Beyond-the-Floor

CAA—Clean Air Act

CEMS—Continuous Emissions

Monitoring System

D/F—Dioxins/Furans

ESP—Electrostatic Precipitator

gr/dscf—Grains per Dry Standard Cubic

Foot

HAP—Hazardous Air Pollutant

HC—Hydrocarbons

HWC/HWI—Hazardous Waste

Combustor/Incinerator

IWS—Ionizing Wet Scrubber

LVM—Low-volatile Metals

LWAK—Lightweight Aggregate Kiln

MACT—Maximum Achievable Control

Technology

MTEC—Maximum Theoretical Emission

Concentration

NESHAPs—National Emission

Standards for HAPs

NODA—Notice of Data Availability

NPRM—Notice of Proposed Rulemaking

NSPS—New Source Performance

Standards

PM—Particulate Matter

RCRA—Resource Conservation and

Recovery Act

SRE—System Removal Efficiency

SVM—Semi-volatile Metals

TEQ—Toxic Equivalent

μg/dscm—Micrograms per Dry Standard

Cubic Meter
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24213

TABLE OF CONTENTS

Part One: Background and Overview of

Today’s Notice

I. Background

II. Overview of Today’s Notice

Part Two: Standards For Hazardous Air

Pollutants (NESHAPs)

I. Regulation of Area Sources

A. Approach to Regulate Area Sources, as

Proposed

B. Positive Area Source Finding for HWCs

C. Title V Permitting Requirements for

Area Sources

II. Revisions to Proposed Standards Using the

Revised Emissions Database and Data

Analysis Methods

A. Notice of Data Availability on the

Revised Emissions Database

B. PM as a Surrogate for Non-Hg Metals

C. Options for Controlling Emissions of

Organic HAPs

D. Accounting for Emissions Variability in

Establishing Emission Standards

E. Re-Evaluation of Proposed MACT

Standards for Incinerators

F. Re-Evaluation of Proposed MACT

Standards for Cement Kilns

G. Re-Evaluation of Proposed MACT

Standards for Lightweight Aggregate

Kilns

Part Three: Implementation

I. Compliance Date Considerations

A. Definition of Compliance Date

B. Pre-Certification of Compliance

C. Consequences of Non-compliance

II. Compliance Requirements

A. Compliance with CO and/or HC

Emission Standards

B. Startup, Shutdown, and Malfunction

Plans

C. Metals Extrapolation and Interpolation

Considerations

D. Consideration of Site-Specific Variances

for Cement Kilns and LWAKs

E. Emissions Averaging for Cement Kilns

III. DRE Testing Considerations

A. Options for Ensuring Compliance with

a DRE Standard

B. DRE As a MACT Versus RCRA Standard

IV. Notification and Reporting Requirement

Considerations

A. Public and Regulatory Notification of

Intent to Comply

B. Data Compression Allowances

V. Waste Minimization and Pollution

Prevention

A. Overview

B. EPA Proposed Flexible Waste

Minimization Incentives

C. Comments Received

D. Comments Requested on Additional

Waste Minimization Incentives

VI. Permit Requirements

A. Coordination of RCRA and CAA

Permitting Processes

B. Permit Process Issues

C. Omnibus and RCRA/CAA Testing

Coordination

Part Four: Miscellaneous Issues

I. 5000 Btu per Pound Policy for Kiln

Products

II. Foundry Sand Thermal Reclamation Units

A. Background

B. Deferral and Variance Options for

Consideration

III. Status of Gaseous Fuels Generated from

Hazardous Waste Management Activities

IV. Regulatory Flexibility Analysis

Part One: Background and Overview of

Today’s Notice

I. Background

On April 19, 1996, EPA proposed

revised standards for three source

categories of hazardous waste

combustors (i.e., hazardous waste

incinerators and hazardous wasteburning cement kilns and lightweight

aggregate kilns (LWAKs)), 61 FR 17358.

After an extension, the comment period

closed on August 19, 1996.

The Agency subsequently published

two Notices of Data Availability

(NODA). The first NODA, published on

August 23, 1996 (61 FR 43501) invited

comment on information pertaining to a

peer review of three aspects of the

proposed rule, additional analyses of

fuel oils that would be used to establish

a comparable fuels exclusion, and

information on a synthesis gas process.

The comment period on that NODA

closed on September 23, 1996. The

second NODA, published on January 7,

1997 (62 FR 960) provided notice and

opportunity to comment on an updated

hazardous waste combustor database

containing the emissions and ancillary

data that the Agency plans to use to

develop the final rule. The comment

period on that NODA closed on

February 6, 1997.

EPA’s proposal to revise standards for

hazardous waste incinerators and

hazardous waste-burning cement kilns

and LWAKs is under joint authority of

the Clean Air Act, as amended, (CAA)

and the Resource Conservation and

Recovery Act, as amended (RCRA). The

proposed emission standards were

developed under the CAA provisions

concerning the maximum level of

achievable control over hazardous air

pollutants (HAPs), taking into

consideration the cost of achieving the

emission reduction, any non-air quality

health and environmental impacts, and

energy requirements. These Maximum

Achievable Control Technology (MACT)

standards, also re ferred to as National

Emission Standards for Hazardous Air

Pollutants (NESHAPs), were proposed

for the following HAPs: dioxins/furans

(D/F), mercury, two semi-volatile metals

(lead and cadmium), four low volatility

metals (antimony, arsenic, beryllium,

and chromium), particulate matter, and

hydrochloric acid/chlorine gas. Other

toxic organic emissions were addressed

by standards for carbon monoxide (CO)

and hydrocarbons (HC).

Because of the joint authorities for

this rule, the proposal also contained an

implementation scheme to harmonize

the RCRA and CAA programs to the

maximum extent permissible by law. In

pursuing a common-sense approach

towards this objective, the proposal

sought to establish a framework that: (1)

Provides for combined (or at least

coordinated) CAA and RCRA permitting

of these facilities; (2) allows maximum

flexibility for regional, state, and local

agencies to determine which of their

resources will be used for permitting,

compliance, and enforcement efforts;

and (3) integrates the monitoring,

compliance testing, and record keeping

requirements of the CAA and RCRA so

that facilities will be able to avoid two

potentially different regulatory

compliance schemes.

II. Overview of Today’s Notice

The Agency received a large number

of public comments in response to the

proposal. The Agency evaluated the

public comments received and their

applicability to the proposed rule. In

those instances where comments

provided new information or new

insights, the Agency has reevaluated

certain aspects of the proposal based on

this new information. The Agency is

issuing this NODA in an effort to inform

the public of: (1) Significant changes the

Agency is considering on aspects of the

proposal based on public comments and

new information; and (2) the Agency’s

own reevaluation (and to some degree

narrowing) of MACT standard-setting

approaches based on new data and (at

least in part) on public comments.

Part Two: Standards for Hazardous Air

Pollutants (NESHAPs)

I. Regulation of Area Sources

In this section, we solicit comment on

making a positive area source finding to

subject hazardous waste combustor area

sources to the same MACT standards

that would apply to major sources and

on whether, under such a finding, area

sources should be subject to Title V

permit requirements.

A. Approach To Regulate Area Sources,

as Proposed

A major source is a source that has the

potential to emit (considering controls)

either 10 tons per year of any hazardous

air pollutant or 25 tons of any

combination of HAPs. Area sources are

any sources which are not major

sources.

The Agency proposed to subject area

sources to MACT standards under

authority of CAA section 112(c)(6). See

61 FR at 17365. That section requires
24214 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

1For area sources, section 112(c)(6) requires the

Agency to establish either MACT standards under

section 112(d)(2), or generally available control

technology (GACT) standards under section

112(d)(5). Given the similarities between major and

area source HWCs as discussed in subsequent

sections of the text, area sources should be subject

to MACT.

2Section 112(c)(6) enumerates the following highpriority hazardous pollutants for special regulation:

alkylated lead compounds, polycyclic organic

matter, hexachlorobenzene, mercury,

polychlorinated biphenyls, and 2,3,7,8-

tetrachlorodibenzofurans and p-dioxin.

3That is, MACT standards under section

112(d)(2) or GACT standards under section

112(d)(5).

4From a technical perspective related to the

nature of common air pollution control devices,

reducing HCl emissions would not generally reduce

emissions of other HAPs.

5For well-designed and operated combustion

systems, D/F emissions are related primarily to

post-combustion particle surface catalyzed

reactions and the temperature of the combustion gas

(the optimum temperature window for formation is

450–750 °F), virtually irrespective of HCl

concentrations in the gas.

6Some commercial incinerators may also be able

to lower their allowable HCl emission levels to

become area sources. It could be more problematic

for on-site incinerators to lower their emissions to

become area sources because facility-wide HAP

emissions must be considered when making the

major/area source determination. For example, onsite incinerators located at large chemical

production facilities would need to reduce HAP

emissions at a large number of sources.

the Agency to subject to MACT

standards 1 all sources in source

categories that account for not less than

90 percent of the aggregate emissions of

each enumerated pollutant. 2 The

enumerated pollutants emitted by

hazardous waste combustors (HWCs)

include mercury (Hg), D/F, and other

polycyclic organic HAPs. The Agency

explained at proposal that HWCs were

significant emitters of D/F and Hg, and

that much of the human health risk from

emissions of HAPs from HWCs comes

from these high priority HAPs, and

D/F in particular.

We received many comments

pertaining to this part of the proposal,

and we will address those comments in

the final rule. The area source issue is

discussed in today’s notice because

commenters said that another, more

appropriate reading of section 112(c)(6)

is that this authority could be used to

apply MACT control to area sources

only for the enumerated HAPs, not the

full array of HAPs that the Agency

proposed to regulate (e.g., particulate

matter (PM), semivolatile metals (SVM),

low volatile metals (LVM)).

Nonetheless, were EPA to adopt this

reading, the Agency continues to believe

that area sources need to be regulated

for this full array of HAPs.

In light of issues commenters raised,

we solicit comment on an alternative

approach that would subject area

sources to all of the MACT standards for

major sources based on the Agency

making a positive area source finding.

B. Positive Area Source Finding For

HWCs

Area sources must be regulated by

technology-based standards 3 if the area

source category is listed pursuant to

section 112(c)(3) based on the Agency’s

finding that these sources (individually

or in the aggregate) present a threat of

adverse effects to human health or the

environment. Such a finding is termed

a positive area source finding. The

Agency is today soliciting comment on

whether a positive area source finding is

appropriate for hazardous waste

incinerators and hazardous waste

burning cement kilns and lightweight

aggregate kilns.

A positive area source finding would

be based on the risk assessment

performed for the proposed rule and

ultimately the final rule. Even though

the sources modeled in support of the

proposed rule may have met the

definition of a major source, EPA

believes their HAP emissions, other

than HCl, are also representative of area

source emissions. This is because, as

discussed below, these example sources

may be able to reduce their HCl

emissions to become area sources

without reducing emissions of D/F, Hg,

or other metal HAPs that could pose

significant health risk.4

Many comments were submitted on

the risk assessment methodology used

to support the proposed rule. We are

considering these comments in

development of the final rule and are

making appropriate changes to the risk

methodology, including modeling

additional facilities. These changes

could affect the Agency’s findings for

both major and area sources. The

Agency is not today reopening the

comment period on the risk assessment.

1. Risks that could be posed by area

source incinerators. We showed at

proposal that baseline emissions from

incinerators could pose high end

individual lifetime cancer risks from D/

F up to 9E–5. See 61 FR at 17389. In

addition, although the risk from low

volatile metals (i.e., As, Be, Cr, and Sb)

was not estimated to exceed 4E–6, the

example sites modeled were not

representative of the short stacks of

many on-site incinerators. The direct

inhalation component of the individual

cancer risk estimates may increase when

incinerators with short stacks are

included in the risk assessment

supporting the final rule.

2. Risks that could Be posed by area

source cement kilns. The Agency

showed at proposal that baseline

emissions from cement kilns could pose

high end individual lifetime cancer

risks from D/F up to 9E–5. See 61 FR at

17402. Although several high D/Femitting cement kilns have recently

reduced their D/F emissions

significantly, a revised risk assessment

may well show that cement kilns (both

area and major sources) can pose

significant health risk at current

emission levels.

3. Risks that could Be posed by area

source lightweight aggregate kilns.

Although the Agency did not show high

baseline D/F cancer risks for LWAKs at

proposal, the risk assessment assumed

extremely low D/F emissions—0.04 ng

TEQ/dscm—based on very limited data

from a single LWAK. However, as

discussed below in section II.G, new

data from two additional LWAKs show

substantially higher emission levels—up

to 4.1 ng TEQ/dscm. At these emission

levels, the high end individual lifetime

cancer risk from D/F could exceed

1E–5.

4. Basis for a positive area source

finding. In evaluating these estimated

risk levels to determine whether they

are sufficient to make a positive area

source finding, the Agency considered

other factors which EPA believes to be

relevant in determining how to exercise

its discretion regarding area source

determinations for these sources:

a. HWC area sources can pose the

same hazard to human health or the

environment as major sources. An area

source may have the same emission

rates of HAPs other than hydrogen

chloride (HCl, the principal HAP that

causes a HWC to be a major source) as

a major source, and thus pose

essentially the same hazard to human

health or the environment. In other

words, sources could have HCl

emissions low enough to avoid a major

source classification, but have emissions

of D/F that could pose a health risk

given that there is no direct correlation

between HCl and D/F emissions.5

In addition, some HWCs that would

currently be classified as major sources

because of their HCl emissions may be

able to lower their HCl emissions to

become area sources. The Agency

projects that all LWAKs are currently

major sources principally because of

their HCl emissions, and that

approximately 80 percent of cement

kilns are major sources, again because of

HCl. These HWCs may be able to lower

their HCl emissions to otherwise

become area sources.6

Sources have until the compliance

date of the MACT standards (i.e., three

years after publication in the Federal
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24215

7Only approximately 30 percent of incinerators

appear to be major sources. This estimate is based

on only the incinerators’ stack emissions, however.

Given that facility-wide emissions of HAPs are

considered when making a major source

determination, many on-site incinerators are likely

to be classified as major sources because they are

located at large petrochemical facilities.

8 It would be particularly problematic from a

RCRA perspective for commercial incinerators that

are area sources to be exempt from MACT

standards.

Register) to make a major source

determination. Many kilns spiked

chlorine in the hazardous waste feed

during compliance testing to get

approval to feed chlorine (and emit HCl/

Cl2) at levels ostensibly higher than

normal. Given that sources ‘‘have the

potential to emit’’ at these ostensibly

higher than normal emission rates, these

emission rates must be used for the

major source determination. See CAA

section 112(a)(1), definition of major

source. These sources may be able to

operate successfully at lower allowable

chlorine feedrates and emission rates,

however. If so, they can elect to retest

their units and base the major/area

source determination on potentially

lower HCl/Cl2 emission rates.

b. RCRA sections 3004(o)(2) and

3004(q) essentially command regulation

of all HWCs. Under this RCRA mandate,

the Agency has regulated all (i.e., both

major and area sources) hazardous

waste incinerators since 1981 (see 46 FR

7678 (Jan. 23, 1981) as amended at 48

FR 14295 (Apr. 1, 1983)) and all

hazardous waste burning cement and

lightweight kilns since 1991 (see 56 FR

7134 (Feb. 21, 1991)). Deferring

regulation of HWCs to the CAA would

not be appropriate unless all HWC

sources were covered. In addition,

although somewhat more than half of

the commercial incinerators appear to

be area sources, the majority of on-site

incinerators are likely to be major

sources.7 The public expectation is that

all HWCs would continue to be

regulated.8

c. MACT controls are reasonable and

appropriate for both major and area

sources. The emission control

equipment (and where applicable,

feedrate control) defined as floor or

beyond-the-floor (BTF) control for each

source category is applicable and

appropriate to area sources. There is

nothing unique about the types and

concentrations of emissions of HAPs

from area sources versus major sources

that would make MACT inappropriate

for an area source.

d. Area source HWCs contribute

significantly to D/F and Hg emissions.

Both area and major source HWCs

contribute significantly to aggregate

emissions of D/F and Hg, two high

priority HAPs. See CAA section

112(c)(6) and proposal discussion at 61

FR at 17366.

For these reasons, the Agency is

taking comment on making positive area

source findings for each of the three

source categories covered by the

proposal. Again, the effect would be to

subject all sources within these

categories to MACT standards, which

also would be the effect of the original

proposal.

C. Title V Permitting Requirements for

Area Sources

Under § 63.1(c)(2), area sources

subject to MACT (or GACT) are subject

to the requirement to obtain a Title V

permit unless the standard for the

source category (e.g., Subpart EEE for

HWCs) specifies that: (1) States will

have the option to exclude area sources

from Title V permit requirements; or (2)

States will have the option to defer

permitting of area sources. The Agency

has determined that if it makes a

positive area source finding and subjects

area sources to MACT standards as

discussed above, the Agency would also

consider subjecting area sources

immediately to Title V permitting

requirements, as provided by

§ 63.1(c)(2)(iii). The Agency has

determined that area source compliance

with Title V permit requirements would

not be ‘‘impracticable, infeasible, or

unnecessarily burdensome’’. See CAA

section 502(a). As noted above, area

sources can be virtually identical to

major sources with respect to size, type

of combustor, and commercial versus

on-site status, except that their mass

emissions of HCl are lower. Thus,

waiver of Title V permitting would not

be warranted.

In addition, if the Agency were to

waive the Title V permit requirement for

area sources, we would be concerned

about the confusion it would likely

create for the regulated community and

the public if the air emissions standards

for some hazardous waste combustors

(even in the same source category) were

addressed in the Title V permitting

process and the air emissions standards

for others were addressed in the RCRA

permitting process. Since a source can

make modifications to their emissions

levels that could change their major/

area source determination, a source

could move from one permitting

program to the other, creating

difficulties for the permitting agencies

in tracking sources and for the public in

trying to participate in or follow the

permitting process. Therefore, it appears

most appropriate from an

implementation standpoint to subject

area sources to Title V permitting. In

this way, all HWCs (both major and area

sources) would be subject to the same

Title V permitting requirements.

II. Revisions to Proposed Standards

Using the Revised Emissions Database

and Data Analysis Methods.

In this section, the Agency discusses

comments on the revised emissions

database and the revised standards that

would result from applying an

engineering evaluation and data

analysis methods to that revised

database. In addition, we discuss several

issues that are generic to the MACT

standards for all three source categories:

(1) Consideration of PM as a surrogate

for non-Hg metal HAPs; (2) options for

controlling emissions of organic HAPs;

and (3) emissions variability.

A. Notice of Data Availability on the

Revised Emissions Database

On January 7, 1997 the Agency

published a NODA on an updated

database of emissions and ancillary

information. See 62 FR 960. The Agency

updated the database used at proposal

to correct errors and include additional

emissions data. The NODA explained

that the updated database would be

used to identify MACT standards for the

final rule and to evaluate economic

impacts and, for RCRA purposes, risks

associated with the final MACT

standards.

The Agency received comments on

the revised database from 16

stakeholders representing the cement

industry, lightweight aggregate industry,

and on-site and commercial

incinerators. The database was revised

again to accommodate the comments

received on the database NODA. The

Agency then re-analyzed the database to

determine the MACT floor standards

discussed below.

We received several specific

comments (i.e., as opposed to generic

and undocumented comments that, for

example, the Agency’s data are

inconsistent with the commenter’s) that

were not accompanied with supporting

documentation. Most of these comments

pertain to miscellaneous data on

feedstream feedrates and equipment

design information that do not have a

significant impact on developing MACT

floor standards under the data analysis

methods discussed in today’s NODA.

Where there was a significant possibility

that the data might affect the Agency’s

determinations, references were rechecked to determine the more accurate

number to be used.

The Cement Kiln Recycling Coalition

(CKRC) provided an extensive run-byrun, HAP-by-HAP comparison of the

Agency’s database with theirs. While
24216 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

9Note, however, that the example incinerators

modeled for the risk assessment had relatively tall

stacks which may not result in the higher ground

level concentrations (and thus higher direct

inhalation risk) that could result from small

incinerators.

10 This is at least partly because a PM control

device alone does not give the same targeted degree

of control for individual metals that a combination

of metal feed control plus a PM control device does.

11 Sb is a non-carcinogen with relatively low

toxicity compared with the other five non-Hg

metals, and would have to be present in hazardous

waste (and emitted PM) at extremely high levels

(perhaps over 1000 times the current levels) to pose

a health hazard. Current data suggest that metals

feedrates generally are either not increasing or

increasing at much lower rates.

potentially useful in some cases, their

submission unfortunately did not

distinguish between significant versus

insignificant differences; nor did they

verify which data were more accurate

for the purposes in question. Within

current time constraints, the Agency has

identified which appear to us to be

significant and relevant differences and

then checked these data to determine

which appear to be more accurate and

has made necessary changes. The

current database, as updated and

revised, is appropriate and sufficient

considering the engineering and data

analysis methods discussed below to

identify MACT standards. For example,

although there may still remain

differences between CKRC’s and the

Agency’s database regarding

electrostatic precipitator (ESP) and

fabric filter design and performance

characteristics, those characteristics are

not germane to the engineering and data

analysis methods for determining

relevant MACT standards, as discussed

below. In these situations, the Agency

has elected not to revise inconsequential

data, particularly where it is not clear

which data are more accurate.

Some overall decisions on data

quality issues have also been made for

purposes of revising the database.

Regarding assigning values to reported

nondetects, we are assuming that

nondetected values were present at onehalf the detection limit. We considered

assuming nondetected values were

present at the full detection limit, but

found in most cases no significant

difference in the MACT data analysis

results. It represents a judgment by the

Agency based on its experience that, for

assessing standards and risk, this more

conservative approach increases our

confidence that standards and risk are

appropriate and acceptable.

In addition, we are excluding data

from sources no longer burning

hazardous waste, as suggested by

several commenters on the proposed

rule. Although such data may well be

indicative of the capabilities of control

equipment and thus relevant, the

resulting database is still large enough

to ensure that potential final MACT

standards can be judged to be

achievable (or not as the case may be)

without including these more

controversial data. Regarding older

emissions data when more recent data

was available for a source, we are

considering all data sets for sources that

currently burn hazardous waste. Both

recent and old data are instructive in

assessing the capabilities of the control

equipment at these operating facilities.

Finally, we screened out so-called

‘‘normal’’ emissions data from the

MACT analyses. Although doing so may

appear counterintuitive at first blush,

one must consider that facility

compliance will generally be based on

operating limits established during the

MACT performance test (except if

compliance is based on a continuous

emissions monitoring system (CEMS)).

During these MACT performance tests,

sources will likely operate under the

same worst-case conditions as they did

during trial burns and Boiler and

Industrial Furnace (BIF) rule

certification of compliance testing.

Operating under worst-case conditions

with respect to emissions and operating

parameters gives operators a wide

allowable envelope of operating limits

needed to efficiently and economically

operate the combustor and yet maintain

compliance. Considering normal

emissions data in the MACT analysis

could inappropriately result in the

Agency establishing a MACT standard

based on normal emissions and

conditions while the source would be

operating under worst-case conditions

to demonstrate compliance. Thus,

emissions while complying with

operating limits would be

inappropriately constrained to below

current normal emission levels, even for

sources equipped with well-designed

and operated MACT floor control.

B. PM as a Surrogate for Non-Hg Metals

The Agency proposed a MACT PM

standard as a surrogate for non-D/F

organic HAPs (that are adsorbed onto

the PM) and for the metal HAPs not

individually regulated under the

proposed metal standards (i.e., Co, Mn,

Ni, and Se). See 61 FR at 17376.

Since proposal, the Agency has

reconsidered in the context of this joint

RCRA-CAA rulemaking whether a

MACT PM emission standard could

serve as a surrogate for six non-Hg metal

HAPs for which the Agency did propose

specific standards—semivolatiles (Cd

and Pb) and low volatiles (As, Be, Cr,

and Sb). This issue arises, in part,

because the risk assessment at proposal

on the MACT standards estimated that

the high-end individual lifetime cancer

risks using 90th percentile metal

emission levels were well below 10¥6

for cement kilns and LWAKs. For

incinerators, the highest estimated

cancer risks exceeded 10–6 but were

below 10¥5.9

To evaluate PM as a surrogate for nonHg metals in the context of this joint

RCRA-CAA rulemaking, questions that

must be addressed are: (1) Would a

MACT PM standard control the six nonHg metals to MACT emission levels in

the special context of hazardous waste

combustors; and (2) would there be

significant health risk at MACT

emission levels that would have to be

addressed with RCRA controls (based at

least in part on site-specific risk

assessments using omnibus authority)?

Because, in the case of hazardous

waste combustors, there are significant

levels of metals in the hazardous wastederived fuel being burned, the Agency

has initially concluded that a MACT PM

emission standard in this particular rule

may not adequately control the six nonHg metals to the nominal MACT

emission levels. The residual risk that

could result from emissions of some of

the six non-Hg metals could be

significant 10, and regulation of these

problematic metals under RCRA would

therefore be warranted. From an

implementation standpoint, this result

of mixed statutory controls is not

desirable. Although establishing six

additional specific limits on the non-Hg

metals eliminates this particular

implementation disadvantage, this

would add to the compliance and

implementation burdens on facility and

regulator alike. Consequently, it does

not currently appear appropriate to use

PM as a surrogate for all six toxic, nonHg metals.

In investigating this issue, however,

we determined that antimony (Sb), one

of the four low volatile metals, may not

warrant direct control. That is, the

MACT PM standard may serve as an

adequate surrogate for Sb to ensure that

it is not emitted at levels that pose a

health risk. 11 We also considered

whether beryllium (Be), another LVM,

warranted control given that it is not

generally present in significant

concentrations in hazardous waste, and

baseline emissions of Be do not appear

to be posing a health hazard. Given that

Be is a toxic carcinogen, however, direct

MACT controls should be provided

even if current feedrates (and emission

rates) are low.

Only a preliminary analysis (see

discussion below) was used to

investigate whether some of the
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24217

12 In addition, metal collection efficiency of the

PM control device varies at different metal

feedrates.

13See, for example, comments submitted by

Chemical Manufacturers Association, RCRA Docket

# F–96–RCSP–FFFFF comment # RCSP–00128.

14 Other metal HAPs (other than Hg and the six

toxic metals covered at proposal) would be

controlled indirectly by the PM standard and any

individual or volatility group metal standards. This

is essentially unchanged from the proposal.

remaining semivolatile and low volatile

metals—Cd, Pb, As, and Cr—may

warrant only indirect control through a

PM standard for any or all of the HWC

source categories. We continue to

believe that direct standards are

warranted for these four metals (either

individually or in volatility groups). For

purposes of public comment, we have

identified MACT standards for these

individual metals in case individual

standards are ultimately deemed more

appropriate than continuing to group

the metals by relative volatility.

However, we remain concerned about

the compliance and implementation

complexities that would be introduced.

(See the discussion below of revised

SVM and LVM standards for each

source category.)

We solicit further comment on how to

ensure appropriate and effective control

of non-Hg metal HAPs while ensuring

that the regulatory scheme and

associated compliance elements are

implementable and not unnecessarily

burdensome. Some of the pertinent

issues are highlighted below for

commenter response.

1. Can PM serve as a surrogate for

SVM and LVM? A MACT PM standard

would provide MACT emissions control

technology (i.e., the air pollution control

device) for non-Hg metals. This is

because stack emissions of non-Hg

metals in combustion gases are

controlled by the PM control device.

Thus, MACT control (i.e., the emission

control device) for PM would also be

MACT control for non-Hg metals.

However, emissions of non-Hg metals

from HWCs are also controlled by the

feedrate of non-Hg metals (for kilns, the

feedrate of non-Hg metals in hazardous

waste) in addition to the PM control

device. Thus, a MACT PM standard

alone may not result in control of nonHg metals to MACT emissions levels

because emissions of non-Hg metals will

vary at a given PM level as feedrate

varies (i.e., emissions of non-Hg metals

will be a greater percentage of PM

emitted as the feedrate rises).

Some commenters have argued that

PM is not a good surrogate for non-Hg

metals emissions. When sources (within

a source category) are considered in the

aggregate, a poor correlation between

PM and non-Hg metals emissions

appears to exist. This is because sources

have various feedrates of the metals and

because different types of PM control

devices have different collection

efficiencies for these metals.12. 13

Nonetheless, at a given source with a

given non-Hg metal feedrate, metal

emissions will correlate with PM

emission levels. Although the

correlation will be different for more

volatile versus less volatile metals,

emissions of these metals will increase

as PM emissions increase.

In summary, although there is a

correlation between PM and non-Hg

metal emissions on a facility-specific

basis, and the MACT PM standard likely

would ensure use of MACT emission

control device for these metals, it may

not ensure attainment of MACT

emission levels of these metals. Given

the potential for HWCs to emit high

levels of some of these metals, metalspecific emission controls—MACT

standards—are warranted either

individually or in volatility groups.

2. Which non-Hg metals warrant

specific control by establishing MACT

emission standards? As an alternative to

establishing MACT standards for SVM

and LVM as proposed, we are reevaluating which non-Hg metals

warrant special control and whether to

establish individual MACT emission

standards for them. 14 As discussed

above, our preliminary analysis

indicates that standards may not be

warranted for Sb. We are continuing to

investigate whether any of the

remaining metals—As, Be, Cd, Cr, and

Pb—may not warrant direct emission

standards but may warrant only indirect

controls via the PM standard. Further,

we are investigating how the metal

standards should be structured: (1)

MACT standards for individual metals;

or (2) MACT standards for volatility

groupings (SVM and LVM) if we

determine, as currently contemplated,

that direct standards for all five

remaining metals are warranted (i.e., as

proposed).

For cement kilns and LWAKs, we

examined a comparison of potentially

allowable emission levels for non-Hg

metals under the BIF rule and actual

allowable (i.e., levels emitted during

Certificate of Compliance (CoC) testing)

emission levels. (Note that the actual

allowable levels are generally much

higher than normal emission levels

because sources spiked metals during

CoC testing.) A wide margin exists—

generally an order of magnitude or

greater—between BIF potentially

allowable emission levels and CoC

allowable emission levels. This means

that: (1) Cement kilns and LWAKs are

not emitting these metals at levels

posing a risk using BIF risk assessment

procedures; and (2) cement kilns and

LWAKs are feeding these metals at rates

well below those that would be allowed

under BIF risk-based limits and, thus,

indirect PM control under MACT may

similarly keep feedrates (and emission

rates) of these metals low.

We also examined data on the

percentage of emitted particulate matter

that each non-Hg metal would have to

comprise to pose a health risk, assuming

BIF risk assessment procedures were

applied. Under this analysis, Pb and Sb

would have to comprise from 10–100

percent of emitted PM to pose a health

risk. Data suggest that these percentages

are not approached in today’s

operations by a wide margin.

These preliminary analyses were

performed assuming BIF risk assessment

procedures. Thus, our evaluation may

not be representative of results that will

be forthcoming shortly using updated,

more detailed procedures for evaluating

risks under the final MACT standards.

For example, the risk assessment for this

rule considers indirect exposure (i.e.,

ingestion and food-chain uptake) while

BIF procedures consider only direct

inhalation. On the other hand, BIF

direct inhalation exposure assessment

procedures are more conservative (i.e.,

result in a higher estimate of risk) than

those that will be used for the final

MACT standards because the Agency

has revised those procedures in part to

consider more realistic exposure

scenarios. Nonetheless, the analyses

discussed above are viewed as

suggestive that regulation of each and

every semivolatile and low volatile

metal as proposed may not be

warranted.

We could not perform similar

preliminary analyses for incinerators

because we do not have dispersion

coefficients readily available that would

be representative of the short stacks

used by many on-site incinerators.

However, a review of the emissions

database indicates that, as expected,

some incinerators—both commercial

and on-site incinerators—emit much

higher levels of these metals than

cement kilns or LWAKs. Nonetheless,

we may find (as may be the case for

cement kilns and LWAKs) that Sb may

not warrant a direct metal-specific

standard for incinerators as well, either

as part of the LVM group or an

individual standard.
24218 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

15The Agency proposed to establish MACT

standards for both CO and HC, but solicited

comment on whether a standard based on one

surrogate or the other may be sufficient. See 61 FR

at 17376.

16The Agency proposed to retain DRE as a RCRA

standard because of concerns that it would be

difficult to self-implement under MACT

implementation procedures. See 61 FR at 17447.

The Agency is reconsidering this issue and solicits

comment on alternative approaches to ensure

compliance with the DRE standard, including

incorporating DRE as a MACT standard.

17See, for example, proposed rule (61 FR at

17367).

18See USEPA, ‘‘Draft Technical Support

Document for HWC MACT Standards (NODA),

Volume I: MACT Evaluations Based on Revised

Database’’, April 1997.

19Or, in the case of LWAKs, where the data set

is essentially complete (i.e., where we have data

from all or most of the sources in the source

category).

20No patterns in process design or operation in

the information we have explain why some sources

thought to be using floor control had significantly

higher emissions than other sources thought to be

using floor control. Where floor control is based on

an emission control device, these high emitters are

likely not in fact using floor controls—considering

the suite of design, operation, and maintenance

factors that affect performance of the control

equipment but on which the Agency has no data.

Where floor control is based on finite control such

as combustion gas temperature or feedrate control,

the high emitters may be experiencing emissions

during the compliance test on the high end of the

range of emissions variability.

21When data are available from fewer than 30

sources, MACT floor is defined as the median

emission limitation achieved by the best five

performing sources. Thus, the best performing three

sources (representing the median (and better

performers)) define MACT in this case.

C. Options for Controlling Emissions of

Organic HAPs

Based on evaluation of the revised

emissions database, the Agency is

soliciting comment on options to

control emissions of organic HAPs by:

(1) Establishing MACT standards for

carbon monoxide (CO) and/or HC

emissions as surrogate indicators of

good combustion conditions; 15 and (2)

ensuring that sources achieve 99.99

percent destruction and removal

efficiency (DRE).16 These options are

presented in Part Three:

Implementation, Sections II and III,

because the DRE issue has

implementation implications, and the

CO/HC issue relates to the DRE issue.

D. Accounting for Emissions Variability

in Establishing Emission Standards

At proposal, the Agency used a

statistical approach to identify an

emission level that MACT floor control

could achieve routinely considering that

the emissions database was comprised

of ‘‘short-term’’ test data. See 61 FR at

17366. To identify an appropriate

standard, a computed variability factor

considering within-test condition

emissions variability was added to the

log-mean of the highest test condition

average for any source using floor

control. The log-mean of the runs for the

standard-setting test condition is the

‘‘design level’—the emission level the

source would be designed to meet to

ensure emissions were less than the

standard 99 percent of the time,

assuming a source had average withintest condition emissions variability

(average based on all sources using floor

control).

We are concerned that this computed

variability factor approach may be

inappropriate in this particular

rulemaking.17 For example, this

computed variability factor led to

illogical results for the PM standards for

incinerators and LWAKs. In the case of

PM, the calculated standard using the

computed variability factor is 50 percent

higher than the current legallymandated RCRA PM limit for

incinerators. For LWAKs, using the

variability factor results in a PM

standard of approximately 0.04 gr/dscf

(corresponding to a design level of 0.022

gr/dscf) nearly twice as high as any PM

emission value in the entire LWAK

database. Further, given that floor

control would be a fabric filter, our

engineering evaluation 18 (and the

LWAK database itself) indicates that a

fabric filter can readily achieve levels of

0.022 or below, not the calculated 0.04.

These inappropriate and illogical

results may flow from either the

variability factor itself or the test

condition average identified as the

standard-setting test condition (to which

the variability factor is added). For

example, the variability factor itself

(which considers within-test conditions

emissions variability) could be

inappropriately high if there are outlier

runs within test conditions that are not

screened out. Although runs in many

test conditions appear to be outliers

(and analytical tests may show them to

be outliers) it can be difficult to justify

screening them out unless there is a

specific technical explanation (e.g.,

unique design or operation feature or

inadequacy) that can be identified.

Unfortunately, this information is often

not available for many potential outlier

data.

As noted, identifying the standardsetting test condition inappropriately

could be a factor. We have very limited

information on the design, operation,

and maintenance characteristics of the

emission control devices and

combustors. Accordingly, we have had

to define MACT floor control very

generically (e.g., ESP or fabric filter), as

discussed below, without attempting to

specify design, operation, and

maintenance characteristics.

Given these concerns and the statute’s

direction to establish the maximum but

achievable floor standard, we request

comment on an alternative approach to

account for emissions variability. This

alternative has two elements. First,

when a large data set from sources using

floor control 19 exists, the range of

emission levels from those sources

should adequately reflect emissions

variability. That is, a standard

established as the highest test condition

average for sources using floor control

represents an emission level that the

control technology is capable of

achieving, considering normal

variability in combustor operations,

emission control device operations, and

test methods. Where these data show

that many sources using floor control

can achieve well below the standard,

this demonstrates that additional

emissions variability considerations are

not warranted. Source(s) with emission

levels close to the standard should be

able to determine how to emit at levels

below the standard based on the specific

design, operation, and maintenance

information available to them,

especially since many other sources

with the same basic equipment are

doing so.20 Second, where only a small

set of data from sources using floor

control exists, the range of emission

levels from these sources may be less

likely to reflect emissions variability. In

this case, consideration of an additional

variability factor (to be added to the

highest test condition average for a

MACT-control facility) may be

appropriate.

The impact of this alternative

approach has been examined. We do not

have a large data set in the expanded

universe for two standards: D/F

standards for incinerators equipped

with waste heat recovery boilers and D/

F standards for LWAKs. In each case,

we have data from only three sources,

and consequently floor control is based

on the suite of controls used by all three

sources.21 If the data set were large, we

would identify the floor level as the test

condition with the highest run average.

But, given the small data set, it is

reasonable from an engineering vantage

point to identify the standard as the

highest single run for the highest test

condition (when the unit was properly

operated).

We discuss below engineering and

data analysis methods and the resulting

standards for each HAP and source

category where a computed variability

factor is not used to establish emission

standards.
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24219

22Additional details of the engineering and data

analysis evaluations performed on the revised

emissions database can be found in the Agency’s

background document: USEPA, ‘‘Draft Technical

Support Document for HWC MACT Standards

(NODA), Volume I: MACT Evaluations Based on

Revised Database’’, April 1997.

23An analysis of gas flowrates in actual cubic feet

per minute (ACFM) indicated that a maximum

flowrate of 20,000 acfm would be within the range

of values that could be selected to designate small

versus medium incinerators. We performed a

similar analysis at proposal and selected a flowrate

of 23,127 to designate small incinerators. See 61 FR

at 17372.

24The Agency requested at proposal comments

on other means of reducing costs to small, on-site

incinerators (e.g., waiving requirements for CEMS).

We will consider all submitted comments on

options to reduce costs on these units in the final

rule.

25Mixture of low level radioactive waste and

hazardous waste.

26See summary of DOE/EPA meeting at RCRA

Docket # F–96–RCSP–FFFFF item # S00270.

Finally, we are using an engineering

evaluation to identify a design level for

each standard for purposes of estimating

economic impacts and, for RCRA

purposes, the risk associated with the

design level for a given MACT standard.

The design level is the emission level to

which the control equipment must be

designed to ensure compliance with the

standard. For the RCRA risk analysis of

the final MACT standards, we will

analyze risks under the more realistic

assumption that a source is emitting at

the design level on average, rather than

right at the standard all of the time.

Based on discussions with several air

pollution control device vendors and

facility operators, a design level of 70

percent of the standard is deemed

appropriate because it is within the

range of reasonable values that may be

encountered—50 percent to 90 percent.

To the extent that industry engineering

experience suggest that a different

design level assumption would be more

typical and reasonable, we invite

commenters to provide that information.

We also considered whether the

design level as a percentage of the

standard (i.e., design factor) should vary

depending on whether the control is

finite (e.g., temperature control or

feedrate control) versus an emission

control device that is affected by various

parameters, or the type of emission

control device (e.g., metals controlled by

feedrate and an ESP or fabric filter).

However, we do not have enough

information to establish such tailored

and case-specific design factors. If

commenters supply sufficient

information, we will consider using this

approach.

As noted, we will use the design

factor to estimate costs of retrofitting for

all sources with emissions exceeding

the standard. For these sources, we will

estimate the costs of upgrading emission

control equipment to meet the design

level. For sources using floor control

(i.e., sources in the expanded universe)

that have emissions greater than the

design level, however, we will not

attribute retrofit costs for compliance.

Given that these sources are using floor

control and that, as discussed above, the

large data set of sources using floor

control and meeting the floor standard

amply accounts for emissions

variability, we will presume that these

relatively high emissions for such floorcontrolled sources represent the high

end of the range of emissions variability.

In other words, when these sources

retest emissions under the same

conditions, their emissions should meet

the standard.

E. Re-Evaluation of Proposed MACT

Standards for Incinerators

We discuss in this section the basis

for the revised standards for incinerators

that result from applying engineering

and data analysis to the revised

emissions database. We also discuss

refinements to analytical approaches

used in the proposal for identifying

floor controls and levels.22 A

comparison of the originally proposed

and potentially revised standards for

existing and new sources is presented in

the table below:

TABLE II.E.—REVISED STANDARDS FOR EXISTING AND NEW INCINERATORS 1

HAP or HAP surrogate

Existing sources New sources

Proposed

standard

Revised

standard

Proposed

standard

Revised

standard

D/F (ng TEQ/dscm) .................................................................................................. 0.20 0.20 0.20 0.20

Hg (μg/dscm) ............................................................................................................ 50 40 50 40

PM (gr/dscf) .............................................................................................................. 0.030 0.015 0.030 0.015

HCl/Cl2 (ppmv) ......................................................................................................... 280 75 67 75

CO (ppmv) ................................................................................................................ 100 100 100 100

HC (ppmv) ................................................................................................................ 12 10 12 10

SVM (μg/dscm) ......................................................................................................... 270 100 62 100

LVM (μg/dscm) ......................................................................................................... 210 55 60 55

1All emission levels are corrected to 7% O2.

1. Subcategorization considerations.

Since proposal, the Agency has refined

potential options for subdividing the

incinerator source category to determine

if subdivided standards would be

appropriate: (1) Small 23 versus large

sources; (2) commercial versus on-site

sources; and (3) small on-site sources

versus large on-site and commercial

sources. In large part, commenters

believed that small, on-site incinerators

should have less stringent standards to

reduce costs of compliance. However,

given that our analysis shows that the

revised standards for the small on-site

sources would either remain the same or

be more stringent under these options,

we continue to believe that subdividing

would be inappropriate.24

We also received comments from the

US Department of Energy (DOE)

suggesting that DOE’s mixed waste 25

incinerators had several unique features

(discussed below) that would warrant

subcategorization.26 We are

investigating whether DOE’s

incinerators pose unique

implementation and compliance

problems and therefore are considering

several options for the final rule: (1) no

subcategorization; (2) subcategorization

for mixed waste incinerators; and (3)

deferral of MACT regulation for mixed

waste incinerators (with RCRA rules

continuing to apply).

Under the No Subcategorization

Option, we would find that the MACT

controls and emission standards

applicable to other incinerators are

appropriate for DOE’s mixed waste

incinerators. Under this option we

could still define special compliance

requirements that account for any

unique features of mixed waste

incinerators.
24220 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

Under the Subcategorization Option,

we would find that because of unique

design or operating features, the MACT

controls or emission standards

identified for other incinerators are not

appropriate for mixed waste

incinerators. MACT standards unique to

these incinerators would be developed,

and special compliance requirements

could be defined.

Under the Deferral Option, we would

determine that we do not have the

resources to make an appropriate MACT

determination on mixed waste

incinerators in time to meet the

schedule for the HWC rulemaking (i.e.,

the Phase I rule establishing MACT

standards for incinerators, cement kilns,

and LWAKs). Regulation of mixed waste

incinerators would be deferred to the

Phase II rule where the Agency will

establish MACT standards for hazardous

waste burning boilers, halogen acid

furnaces, and sulfur recovery furnaces.

The RCRA rules which now apply

would continue to do so.

DOE suggests that its mixed waste

incinerators have several unique

features that would require

subcategorization and special

compliance standards:

• Each of DOE’s four conventional

incinerators meet the Agency’s

definition of small incinerators (i.e.,

<20,000 acfm gas flow rate), and one is

batch-operated only once or twice a year

with a gas flow rate of 3,000 acfm.

• Several mixed waste thermal

treatment units meeting the Agency’s

definition of an incinerator are small

vitrification devices designed to process

metal bearing wastes and feed wastes

with extremely low organic content.

• Given that most of the mixed waste

incinerators are very small units, a

mass-based emission limit would be

more appropriate than a concentrationbased emission limit.

• Approximately 95 percent of the

mixed waste that is incinerated is

‘‘legacy waste’’ generated during

production of nuclear weapons from

1943 until 1989 and may contain high

levels of mercury that cannot be

lowered by source reduction.

• Control of mercury emissions using

activated carbon injection (ACI) would

be problematic because the spent carbon

would be a mixed waste, and if it

contained more than 260 ppm of

mercury, mercury retorting would be

required under the Agency’s land

disposal restrictions even though there

are no retorters in the country that

manage mixed waste (and so a variance

would have to be obtained under

§ 268.44).

• Given that CEMS are not yet

demonstrated for multi-metals (and a

CEMS requirement for mercury alone is

also problematic for the final Phase I

rule), compliance with MACT metal

emission limits would be based on

feedrate limits for metals in feedstreams,

a potentially unworkable approach for

mixed waste since sampling and

analysis of radioactive feedstreams

raises serious human health concerns.

• DOE has negotiated plans and

agreements with States under Site

Cleanup Agreements mandated by

RCRA section 3021(b) and CERCLA

section 120(e), and such plans and

agreements would probably require

renegotiation (and delay) to comply

with the proposed MACT standards.

The Agency is continuing to

investigate these issues and will make a

determination regarding the appropriate

regulatory option in the final rule.

2. Dioxins and Furans (D/F) a. MACT

floor for existing sources. We proposed

a MACT floor standard of ‘‘0.20 ng TEQ/

dscm or gas temperature at the PM

control device ≤400°F’’ based on floor

control of temperature at the PM control

device. During subsequent analysis of

the revised database, we noticed again

that incinerators equipped with waste

heat boilers have significantly higher D/

F emissions than other incinerators.

This is likely because the heat recovery

boiler precludes rapid temperature

quench of combustion gases to a

temperature of ≤400°F (usually with a

wet scrubber), which would be floor

control for non-waste heat boilers. Floor

control for waste heat boilers would be

rapid quench of combustion gases at the

exit of the boiler to a temperature of

≤400°F.

Based on the revised database, the

floor standard for waste heat boilers

would be ‘‘0.20, or 12 ng TEQ/dscm and

a temperature of ≤400°F at the PM

control device.’’ Given that the waste

heat boiler expanded universe (i.e., the

entire database) is comprised of only

three sources, the highest single run for

the test condition with the highest run

average is a reasonable floor level. (Note

that if this were a large data set, we

would define the floor level simply as

the highest test condition average.) This

floor level is 50 percent higher than the

highest test condition average, and thus

appears to be a level that waste heat

boilers should be able to meet routinely

using floor control.

The floor standard for non-waste heat

boilers would be ‘‘0.20, or 0.40 ng TEQ/

dscm and a temperature of ≤400°F at the

PM control device.’’ This standard is

based on arraying emission levels for

sources using floor control and

screening out four test conditions with

anomalously high emissions. Three of

these test conditions were from sources

for which we had other test conditions

with emissions averages well below 0.40

ng TEQ.

We did not originally propose

separate standards for waste heat boilers

because the floor standard at proposal

was ‘‘0.20 ng TEQ/dscm or temperature

at the PM control device of <400°F.’’

Waste heat boilers could meet that

standard, and moreover, we proposed a

BTF standard of 0.20 ng TEQ/dscm for

all incinerators (a preference we do not

depart from in today’s notice). Today,

however, we are presenting the option

of stating the standard in the form of a

TEQ level combined with a maximum

temperature at the PM control device.

This form of the standard is consistent

with the revised data, and would result

in somewhat lower emissions. This is

because, without the TEQ limit, some

sources could exceed that TEQ level at

the specified temperature.

b. BTF considerations for existing

sources. Incinerators can be equipped

with ACI at temperatures ≤400 °F to

achieve D/F levels below 0.20 ng TEQ/

dscm. Given the limited application of

the technology to control D/F emissions

from hazardous waste incinerators and

given that control efficiency is likely to

decrease at D/F emission levels below

0.20, a BTF standard of 0.20 ng TEQ/

dscm would continue to be appropriate.

See proposal for extended discussion,

61 FR at 17382.

Another option arising from the

refinement of our original analysis is to

establish a BTF standard for waste heat

boilers at ‘‘0.20, or 0.40 ng TEQ/dscm

and a temperature of ≤400 °F at the PM

control device’’, and to remain at the

floor standard for non-waste heat

boilers. These standards would ensure

that most, but not all, sources would

have emissions ≤0.20 ng TEQ/dscm.

Given that only a few sources would

need to take additional measures to get

their emissions below 0.20, however, it

would be appropriate to establish a 0.20

BTF standard, assuming this level

remains appropriate after considering

statutory factors for establishing

standards more stringent than the floor.

c. MACT floor for new sources. At

proposal, we identified the same floor

control for new sources as for existing

sources: wet scrubbing and ≤400 °F at

the PM device. This is because the

sources with the lowest emissions used

this control. In re-evaluating the

database for this NODA, however, an

engineering evaluation may be more

appropriate to identify ACI as floor

control because one source (i.e., the

single best controlled source) uses it.

Even though most sources using rapid

quench by wet scrubbing can achieve D/

F levels less than 0.20 TEQ, some
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24221

27USEPA, Section 5 of ‘‘Draft Technical Support

Document For HWC MACT Standards, Volume III:

Selection of Proposed MACT Standards and

Technologies,’’ February 1996.

sources using wet scrubbing have higher

D/F levels. ACI operated at 400 °F or

lower can universally achieve D/F levels

of 0.20 ng TEQ/dscm or less and is thus

the better performing technology. (Note

that waste heat boilers cannot use rapid

quench of combustion gases but can use

ACI.)

Although the source equipped with

ACI (Waste Technologies Industries) is

achieving D/F levels of 0.07 ng TEQ/

dscm, we believe that it is appropriate

to conclude that ACI can routinely

achieve a standard of 0.20 ng TEQ/dscm

given the limited application to date of

the technology for hazardous waste

incinerators and the uncertainties about

how much ACI control efficiency is

reduced at extremely low D/F emission

concentrations. However, we

specifically invite comment on the

potential levels that can be reached with

ACI, and on industry-wide achievability

of 0.07 ng TEQ/dscm as the floor for

new sources.

d. BTF considerations for new

sources. At proposal, BTF for new

sources was based on performance of

ACI given that floor control was based

on performance of rapid quench. Under

today’s analysis, MACT floor for new

sources would be based on ACI.

Although carbon beds would be able to

achieve lower emissions, they are not

thought to be cost-effective (particularly

if the floor for new sources was well

below 0.20 ng TEQ/dscm), and a BTF

standard would likely not be

appropriate.

3. Mercury (Hg). a. MACT floor for

existing sources. At proposal, the

Agency identified floor control as either

(1) feedrate control of Hg at an

maximum theoretical emission

concentration (MTEC) not to exceed 19

μg/dscm, or (2) wet scrubbing with

feedrate control of Hg at an MTEC not

to exceed 51 μg/dscm. We proposed a

floor standard of 130 μg/dscm.

Mercury emissions from incinerators

are currently controlled by limiting the

feedrate of Hg combined with some

removal by air pollution control systems

(APCS). There are two APCS techniques

currently used by hazardous waste

incinerators (HWIs) to control Hg: wet

scrubbers and ACI. Although primarily

intended for acid gas control, nearly all

incinerators employ wet scrubbers that

capture the soluble forms of Hg species

(e.g., mercury salts). ACI is used by one

incinerator for control of Hg (and D/Fs).

The Agency also has data from one

additional facility using ACI; however,

these data were generated during a

demonstration testing program.

Review of the updated Hg data in the

revised database shows that feedrates

vary substantially. Generally the higher

feedrates are the result of Hg spiking.

We re-evaluated the revised database for

today’s notice using a data analysis

method similar to that used at proposal

to determine floor levels: (1) Rank Hg

emissions from lowest to highest; (2)

define as floor control the air pollution

control device (APCD) and associated

highest Hg MTEC for the 6 percent of

sources with the lowest emissions; and

(3) define as the floor standard the

highest test condition average emissions

of any test condition operated at or

below the Floor MTEC. Using the

revised database, MACT control would

be defined as wet scrubbing with a

MTEC of 50 μg/dscm, and the revised

floor standard would be 40 μg/dscm.

Nearly 60 percent of HWIs for which we

have data are achieving this level.

b. BTF considerations for existing

sources. The Agency originally

considered flue gas temperature

reduction to 400 °F or less followed by

ACI as the BTF option for improved Hg

control. As discussed at proposal, EPA

believes that ACI incinerator

applications can achieve Hg emission

reductions greater than 90 percent. In

the Notice of Proposed Rulemaking

(NPRM), the Agency proposed a BTF

standard of 50 μg/dscm.

As mentioned above for existing

sources, the Agency has in its database

Hg data from one facility (with two test

conditions) currently employing ACI as

a permanent application. Both test

conditions achieved Hg removal

efficiencies between 97 and 98 percent

at varying Hg feedrates. The Agency also

has data from a second facility

generated during a demonstration test

that show about a 98 percent

effectiveness at capturing Hg though at

one of the highest feedrates in the

database. These data, in addition to ACI

applications on full-scale municipal

waste combustors and medical waste

incinerators,27 support the Agency’s

assumption that ACI systems can

readily achieve capture efficiencies of

90 percent or more on incinerators.

In light of the revised database, EPA

can initially identify 4 μg/dscm as the

potential BTF standard based on ACI

and flue gas temperature reduction to

400 °F or less. This is based on a source

achieving the floor level of 40 μg/dscm

and then applying ACI with a 90

percent removal efficiency. However, a

BTF level of 4 μg/dscm will likely raise

significant cost-effectiveness

considerations. Given that the floor

level discussed today would be

substantially lower than the proposed

floor, a BTF standard of 4 μg/dscm

would be less cost-effective than the

BTF levels of 30 μg/dscm and 5 μg/dscm

analyzed at proposal.

c. MACT floor for new sources. At

proposal, the floor control for new

sources was similar as for existing

sources: wet scrubbing with feedrate

control of Hg at an MTEC not to exceed

51 μg/dscm. We proposed a floor

standard of 115 μg/dscm.

As discussed for existing sources,

both wet scrubbing and ACI are used for

Hg control. The single best performing

source for Hg control in our database,

measured by lowest emissions, is a wet

scrubber with Hg feedrate, expressed as

a MTEC, of 50 μg/dscm. Since MACT for

new HWIs is identical to MACT for

existing sources, analysis of emissions

using these or better controls would

result in a floor level for new HWIs of

40 μg/dscm.

The Agency also considered a MACT

floor based on ACI, a technology more

effective at Hg control than typical wet

scrubbing applications. The three test

conditions in the database indicate that

ACI was effective in removing over 97

percent of Hg. However, the Hg feedrate

during the single best ACI test condition

was higher than the feedrate associated

with the single best performing wet

scrubber. In fact, Hg feedrates during the

ACI test conditions ranged from 5 to 300

times greater than the wet scrubber

MTEC level. To determine an emissions

level that ACI could routinely achieve,

we applied a capture efficiency of 90

percent to a Hg MTEC of 500 μg/dscm,

a typical feedrate identified by a MTEC

breakpoint analysis. Thus, using the

revised database, the floor level for the

ACI evaluation would be 50 μg/dscm

which is slightly higher than the wet

scrubber floor analysis. The floor for

new sources based on the wet scrubber

evaluation appears to be more

appropriate because the floor level for

new sources should be at least as

stringent as for existing sources.

d. BTF considerations for new

sources. At proposal, BTF for new

sources was based on ACI. Similar to

existing sources, the Agency reconsidered the use of ACI as the BTF

technology. We identified a level of 4

μg/dscm as a potential BTF standard for

new sources based on ACI and flue gas

temperature reduction to 400 °F or less.

As discussed for existing sources, this

BTF level based on ACI will likely raise

significant cost-effectiveness

considerations.

4. Particulate Matter (PM). a. MACT

floor for existing sources. At proposal,

EPA defined floor control based on

either (1) a fabric filter with an air-to-
24222 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

cloth ratio of 10 acfm/ft2, or (2) a venturi

scrubber used with an ionizing wet

scrubber (IWS). The resulting floor

level, which included a statisticallyderived variability factor, was 0.107 gr/

dscf. Since this level is higher than the

current federal standard of 0.08 gr/dscf,

the Agency identified the floor level as

0.08 gr/dscf.

Today, in light of the revised

database, EPA is taking comment on two

refined engineering and data analysis

methods to identify the PM MACT floor

for HWIs. The evaluation technique and

results from both analyses are presented

below.

For the first (and possibly EPA’s

preferred) data method, EPA would use

the following steps to identify the PM

floor level: (1) Identify all PM control

equipment currently in use within the

HWI source category, regardless of

measured performance; (2) identify as

MACT control those PM APCD

applications used by at least 6 percent

of sources that could be expected to

routinely and consistently achieve

superior PM performance relative to all

control strategies considered; and (3)

identify an emissions level that welldesigned, operated and maintained

MACT controls can readily achieve

based on generally-accepted technical

and engineering information.

Using this approach, MACT controls

would be fabric filter, IWS, and ESP.

Based on the revised database, EPA’s

evaluation of the MACT floor

performance level readily achievable by

a well designed, operated and

maintained MACT control device (fabric

filter, IWS, ESP) is 0.015 gr/dscf. Note

that even though the PM MACT floor is

based on fabric filter, IWS and ESP

APCDs, a source is not required to

employ MACT floor control but rather

only achieve the standard.

Approximately 75 percent of sources

employing MACT (measured by

available test condition data) currently

are achieving 0.015 gr/dscf. An

evaluation of the remaining PM data

exceeding 0.015 gr/dscf from sources

ostensibly employing MACT indicate

that 20 to 40 percent of these data may

be inappropriate for inclusion (e.g., an

incinerator with multiple test

conditions well below and a few above

0.015 gr/dscf). Generally, over 50

percent of HWIs, regardless of the PM

control currently employed, are

currently achieving a 0.015 gr/dscf

level.

The second refined data evaluation

method EPA is considering for PM Floor

analysis is similar to the standardsetting process applied at proposal. This

evaluation is a four-step process: (1)

Rank all PM emissions data and identify

the MACT floor controls used by the

best performing 6 percent of sources; (2)

develop the expanded universe to

include all sources employing MACT

control, without further characterizing

MACT control (e.g., air-to-cloth ratio of

the fabric filter, specific collection area

for an ESP) as done in the proposal

because of the absence of reliable

detailed design, operating, and

maintenance information in the

database; (3) for each PM test condition,

evaluate the corresponding SVM system

removal efficiency (SRE) and screen out

sources that have relatively poor SREs

(i.e., outliers above a breakpoint in the

data array), which are indicators of poor

design, operation, and maintenance

characteristics of the MACT controls at

the source; and (4) identify the MACT

floor equal to the highest test condition

average of all test conditions in the PM

expanded universe.

Using this alternative evaluation

approach as applied to the revised

database, MACT would be based on any

of the following PM controls: (1) Fabric

filter, (2) IWS, (3) ESP, or (4) venturi

scrubber burning liquid low ash wastes.

The resultant MACT floor would be

0.029 gr/dscf. Over 70 percent of HWIs,

regardless of the PM control equipment

employed, are currently achieving this

level. A potential drawback of using this

second alternative evaluation technique

is that nearly 75 percent of the available

incinerator PM data do not have

corresponding SVM data such that a

SRE could be calculated. This impacts

our ability to identify and screen out

poorer performing MACT APCDs from

the expanded universe, a critical step in

evaluating an appropriate performance

level achievable by MACT control. As a

result, this evaluation technique may

not be appropriately identifying a PM

floor level representative of MACT. For

these reasons, the first data method

evaluation appears to be more reliable

and sound for the Agency’s revised

database. The Agency requests

comments on the both data analysis

methods presented.

In the NPRM, the Agency proposed

that sources maintain continuous

compliance with the PM standard

through the use of a PM CEMS. A

decision whether to require incinerators

to install a PM CEMS will be made at

the completion of an on-going

demonstration testing program to

determine if at least one PM CEMS can

meet the proposed performance

specifications. Since the floor standards

discussed above were based on manual

test method data, the Agency will reevaluate at the completion of the CEMS

testing program whether these PM floor

standards would be appropriate in the

event that the final rulemaking requires

continuous compliance with a PM

CEMS. The Agency will notice the

results and conclusions of the

demonstration test program in the

docket for the HWC rule.

b. BTF considerations for existing

sources. In the NPRM, the Agency

proposed a BTF level of 0.030 gr/dscf

and solicited comment on an alternative

BTF level of 0.015 gr/dscf based on

improved PM control.

Based on the revised database, we can

evaluate a reduced PM emissions level

lower than 0.015 gr/dscf as the BTF

standard (in conjunction with

corresponding BTF reductions in SVMs

and LVMs) for existing HWIs. This

would require an improved PM

collection technology such as the use of

more expensive bag material for fabric

filters or increased plate area or power

input to an ESP. Given that the

alternative floor level analyses

presented today would be substantially

lower than the proposed floor and BTF

levels, significant cost-effectiveness

considerations come into play and

suggest that a BTF standard may not

ultimately prove to be appropriate.

c. MACT floor for new sources. At

proposal, the Agency defined floor

control as a fabric filter with an air-tocloth ratio of less than 3.8 acfm/ft2. The

proposed floor level was 0.039 gr/dscf.

Based upon our evaluation of the

revised database, the floor control and

emission level discussed above for

existing sources would also appear to be

appropriate for new sources. If this

eventuates, then MACT floor control

would be a well-designed and properly

operated PM control device (e.g., fabric

filter, IWS, or ESP), and the MACT floor

for new HWIs would be around 0.015

gr/dscf.

d. BTF considerations for new

sources. At proposal, EPA proposed the

same BTF standard of 0.030 gr/dscf

(based on improved PM control) as that

proposed for existing sources.

Today, given the cost-effectiveness

considerations discussed above for

existing sources, the Agency is inclined

to think that a BTF standard beyond a

PM floor level of 0.015 gr/dscf (and

corresponding BTF reductions for SVMs

and LVMs) would not ultimately prove

to be acceptable.

5. Semivolatile metals (SVM)

(cadmium and lead) a. MACT floor for

existing sources. At proposal, EPA

defined floor control as either (1) a

venturi scrubber with a MTEC not to

exceed 170 μg/dscm, (2) a combination

of an ESP and wet scrubber with a

MTEC not to exceed 5,800 μg/dscm, or

(3) a combination of venturi scrubber

and IWS with a MTEC less than 49,000
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24223

μg/dscm. The proposed floor level was

270 μg/dscm.

HWIs use a combination of good PM

control and limiting hazardous waste

feedrates to control SVM emissions.

SVMs, which typically vaporize at

combustion chamber temperatures and

recondense onto small-size particulates

in the APCD, are controlled most

efficiently by technologies that are

effective at capturing fine PM. EPA’s

revised database shows that SVM

emissions vary substantially from 2 to

nearly 30,000 μg/dscm.

The refined data analysis method

used by EPA to evaluate and identify a

MACT floor would be based directly on

the results from the PM floor analyses

discussed above. As mentioned there, a

floor of 0.015 gr/dscf would appear to

represent the MACT floor for HWIs

based on good PM control. Since SVMs

are controlled, in part, by a welldesigned and operated PM control

devices, it follows that sources

achieving this PM performance level at

typical SVM feedrates should also be

controlling SVMs emissions.

Therefore, in its refined SVM analyses

of the revised database, the Agency first

considers all SVM data when

corresponding PM measurements are

below 0.015 gr/dscf. To identify the

SVM floor from these data, we would

determine either the highest SVM test

condition average or the level that

excludes sources achieving substantially

poorer SVM control than the majority of

sources. It is most likely appropriate to

use the latter approach—excluding

sources with significantly poorer SVM

performance—because their higher SVM

emissions may be the result of

exceedingly high SVM feedrates or some

other factor that cannot be readily

identified with available information

(e.g., sampling or analysis anomalies).

An SVM emissions breakpoint analysis

is the approach for excluding these

poorer performing test conditions.

Applying this evaluation technique to

the revised HWI SVM database results

in a MACT floor of 100 μg/dscm.

Approximately 53 percent of all HWI

SVM test condition data, regardless of

PM emissions level, are currently

achieving this emissions level.

As discussed above for PM, the

Agency is soliciting comment on an

alternative evaluation of the HWI PM

data which identified a floor of 0.029 gr/

dscf. Conducting the same SVM floor

analysis discussed above when PM

measurements were below 0.029 gr/dscf

also results in the same floor of 240 μg/

dscm. Approximately 60 percent of all

HWI SVM test condition data, regardless

of PM emissions level, are currently

achieving this emissions level.

Finally, as discussed in an earlier

section, a preliminary analysis indicates

that MACT standards may not be

warranted for one HAP metal, antimony.

Since the number of metals being

considered for MACT standards may

change, we are investigating the

appropriate structure of metals

standards (e.g., retain the volatility

groups or establish individual metals

standards). Using the refined method

discussed above for SVM, we analyzed

the revised database with respect to Cd

and Pb data. The floor analysis

corresponding to PM measurements

below 0.015 gr/dscf would result in the

following floor levels: Cd 20 μg/dscm,

and Pb 95 μg/dscm. The alternative data

analysis method for individual metals

when corresponding PM measurements

were below 0.029 gr/dscf would result

in the following floor levels: Cd 57 μg/

dscm, and Pb 95 μg/dscm.

b. BTF considerations for existing

sources. In the NPRM, the Agency

considered a BTF standard for SVMs

based on improved PM control below

0.030 gr/dscf. However, the Agency

concluded that a BTF standard would

not be cost-effective given that the floor

level alone would result in an estimated

94 percent SVM reduction in emissions.

As discussed for PM BTF

considerations, we also re-evaluated the

possible appropriateness of using a

reduced PM emissions level based on

improved PM control as a BTF standard

(taking into consideration

corresponding BTF reductions in SVMs)

for existing HWIs. Given that the

alternative PM floor level analyses

presented today would be lower than

the proposed floor and BTF floor levels,

significant cost-effectiveness

considerations emerge and suggest that

a BTF standard for either SVMs or

individual Pb or Cd standards based on

improved PM control may not

ultimately prove to be cost-effective.

If, however, the revised risk

assessment yet to be conducted would

show significant risk at a SVM floor

standard of either 100 μg/dscm or 240

μg/dscm, which are floor levels from the

two data analysis methods discussed

above, the Agency will determine

whether a BTF standard based on

control of SVM feedrate to levels below

those at the floor would be appropriate.

This feedrate limitation would in turn

reduce SVM emissions. The BTF

standard and the corresponding level of

feedrate control would be dictated by

considerations of cost-effectiveness and

the need to establish more stringent

RCRA-related controls.

c. MACT floor for new sources. At

proposal, the Agency defined floor

control, based on the best performing

source, as a combination of venturi

scrubber and IWS with a MTEC less

than 49,000 μg/dscm. The proposed

floor level for new HWIs was 240 μg/

dscm.

Based upon our re-evaluation of the

database, the floor control and emission

level discussed above for existing

sources for PM and SVMs would also

appear to be appropriate for new

sources. In this event, MACT floor

control would be a well-designed,

operated and maintained PM control

device (e.g., fabric filter, IWS, or ESP)

achieving the PM floor level of 0.015 gr/

dscf, and the MACT floor would be

around 100 μg/dscm.

As discussed above, the Agency is

soliciting comment on an alternative

evaluation of the revised SVM database

which concludes that MACT floor

control is a well designed, operated and

maintained PM control device (i.e.,

fabric filter, IWS, or ESP) achieving a

PM level of 0.029 gr/dscf. The floor

analysis considering all revised SVM

data when corresponding PM

measurements are below 0.029 gr/dscf

results in a floor for new sources of 240

μg/dscm.

Finally, we have evaluated what

individual metal floor levels for new

sources would be. When PM

measurements are below 0.015 gr/dscf,

the analysis would result in floor levels

for Cd of 20 μg/dscm and for Pb 95 μg/

dscm. Under the alternative data

analysis method for individual metals

when PM measurements were below

0.029 gr/dscf, floor levels would be 57

μg/dscm for Cd and 95 μg/dscm for Pb.

d. BTF considerations for new

sources. In the NPRM, the Agency

proposed a BTF level of 62 μg/dscm

based on improved PM control below

0.030 gr/dscf.

As discussed for PM, a reduced PM

emissions level based on improved PM

control could be considered in

evaluating a potential BTF standard

(considering corresponding BTF

reductions in SVMs and LVMs) for new

HWIs. Because the PM floor level

presented today would be substantially

lower than the proposed floor and

proposed BTF floor level, costeffectiveness issues are again raised and

suggest that a BTF standard for either

SVMs or individual Pb or Cd standards

based on improved PM control may

likewise ultimately prove to be

inappropriate.

6. Low volatile metals (LVM) (arsenic,

beryllium, and chromium). a. MACT

Floor for Existing Sources. At proposal,

EPA defined floor control as either (1)

a venturi scrubber with a MTEC not to

exceed 1,000 μg/dscm, or (2) an IWS

with a MTEC less than 6,200 μg/dscm.
24224 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

28Although a specific feedrate (i.e., MTEC) level

is not used to define MACT floor, feedrate control

is part of floor control to achieve the 75 ppmv

standard using wet scrubbing (i.e., a source would

probably not be able to feed chlorine at extremely

high rates and still achieve the standard using wet

scrubbing). Further, as discussed below in the text,

The proposed floor level was 210 μg/

dscm, which included antimony.

HWIs use a combination of good PM

control and limiting hazardous waste

feedrates to control LVM emissions.

LVMs are less likely to vaporize at

combustion temperatures and therefore

partition primarily to the residue or

adsorb onto particles in the combustion

gas. EPA’s database shows that LVM

emissions from HWIs vary widely from

1 to over 130,000 μg/dscm.

To identify a LVM MACT floor, the

Agency used the same data analysis

method applied to the revised SVM

database. As was determined in the PM

analysis of the revised database, a floor

of 0.015 gr/dscf represents MACT for

HWIs based on good PM control.

Considering all LVM data from sources

achieving a PM level 0.015 gr/dscf or

better, the Agency’s evaluation of the

revised HWI data results in a LVM floor

of 55 μg/dscm (excluding sources above

a breakpoint and therefore achieving

substantially poorer LVM emissions

than the majority of sources). Over 70

percent of HWI LVM test condition data

are currently achieving this emissions

level.

As discussed earlier, the Agency is

soliciting comment on an alternative

evaluation of the revised HWI PM data

which identified a floor of 0.029 gr/dscf.

Evaluating the revised LVM data using

this method results in a LVM floor of

190 μg/dscm. Approximately 90 percent

of HWI LVM test condition data are

currently achieving this level.

Finally, as discussed in an earlier

section, a preliminary analysis indicates

that MACT standards may not be

warranted for one HAP, antimony. Since

the number of metals being considered

for MACT standards may change, we are

investigating the appropriate structure

of metals standards (e.g., retain the

volatility groups or establish individual

metals standards). Using the refined

method discussed above for LVM, we

analyzed the revised database with

respect to As, Be, and Cr (hexavalent).

The floor analysis corresponding to PM

measurements below 0.015 gr/dscf

results in the following floor levels: As

21 μg/dscm, Be 2 μg/dscm, and Cr

(hexavalent) 3 μg/dscm. The alternative

data analysis method for individual

metals when corresponding PM

measurements were below 0.029 gr/dscf

results in the following Floor levels: As

21 μg/dscm, Be 2 μg/dscm, and Cr

(hexavalent) 5.5 μg/dscm.

The Agency is concerned that some of

the potential floor standards for some

individual metals (e.g., Be, Cr

(hexavalent)) may be present at levels

approaching practical quantitation

limits (PQLs). PQLs are the lowest level

of quantification that the Agency

believes a competent analytical

laboratory can be expected to reliably

achieve. The Agency will investigate

whether this issue may need to be

addressed in the development of any

individual metals standards that may be

considered for the final rulemaking. We

invite comment on the issue of PQLs

and LVM BTF standards.

b. BTF considerations for existing

sources. In the NPRM, the Agency

considered a BTF standard for LVMs

based on improved PM control below

0.030 gr/dscf. However, the Agency

concluded that a BTF standard would

not be cost-effective given that the floor

level alone would result in an estimated

91 percent LVM reduction in emissions.

As discussed for PM, a reduced PM

emissions level based on improved PM

control could be considered in

evaluating a potential BTF standard

(taking into consideration

corresponding BTF reductions in LVMs

and SVMs) for existing HWIs. Because

the PM floor level presented today

would be substantially lower than the

proposed floor and BTF floor levels, a

BTF standard for either LVMs or

individual As, Be, and Cr (hexavalent)

standards based on improved PM

control would raise significant costeffectiveness concerns and may not be

appropriate.

If, however, the revised risk

assessment yet to be conducted would

show significant risk at a LVM floor

standard of either 55 μg/dscm or 190 μg/

dscm, which are floor levels from the

two data analysis methods discussed

above, the Agency will determine

whether a BTF standard based on

control of LVM feedrate to levels below

those at the floor would be appropriate.

This feedrate limitation would in turn

reduce LVM emissions. The BTF

standard and the corresponding level of

feedrate control would be dictated by

considerations of cost-effectiveness and

the need to establish more stringent

RCRA-related controls.

c. MACT floor for new sources. At

proposal, the Agency defined floor

control, based on the best performing

source, as a venturi scrubber with a

MTEC less than 1,000 μg/dscm. The

proposed floor level for new HWIs was

260 μg/dscm.

Based upon our re-evaluation of the

database, the floor control and emission

level discussed above for existing

sources for PM and LVMs would also

appear to be appropriate for new

sources. MACT floor control is a welldesigned, operated and maintained PM

control device (e.g., fabric filter, IWS, or

ESP) achieving the PM floor level of

0.015 gr/dscf, and analysis of the

revised data results in a LVM MACT

floor of 55 μg/dscm.

As discussed above, the Agency is

soliciting comment on an alternative

evaluation of the revised LVM database

which identifies MACT floor control as

a well-designed, operated and

maintained PM control device (e.g.,

fabric filter, IWS, or ESP) achieving a

PM level of 0.029 gr/dscf. The floor

analysis considering all revised LVM

data when corresponding PM

measurements are below 0.029 gr/dscf

results in a floor for new sources of 190

μg/dscm.

Finally, individual metal floor levels

for new sources, when PM

measurements are below 0.015 gr/dscf,

are: As 21 μg/dscm, Be 2 μg/dscm, and

Cr (hexavalent) 3 μg/dscm. Under the

alternative data analysis method for

individual metals when PM

measurements are below 0.029 gr/dscf,

the floor levels are: As 21 μg/dscm, Be

2 μg/dscm, and Cr (hexavalent) 5.5 μg/

dscm. [Note: The same PQL concerns

would be present here as well.]

d. BTF considerations for new

sources. In the NPRM, the Agency

proposed a BTF level of 60 μg/dscm

based on improved PM control below

0.030 gr/dscf.

As discussed for PM BTF

considerations, the Agency considered a

reduced PM emissions level based on

improved PM control as the BTF

standard (taking into consideration

corresponding BTF reductions in LVMs

and SVMs) for new (and existing) HWIs.

Because the alternative PM floor level

presented today is substantially lower

than the proposed floor and BTF floor

levels, a BTF standard for either LVMs

or individual As, Be, or Cr (hexavalent)

standards based on improved PM

control may be inappropriate in light of

the cost-effectiveness issues inherent in

this scenario.

7. Hydrochloric Acid and Chlorine

(HCl/Cl2). a. MACT Floor for Existing

Sources. At proposal, the Agency

defined floor control as wet scrubbing

with a chlorine MTEC (i.e., maximum

theoretical emission concentration) up

to 2.1E7 ‘‘μg/dscm and proposed a floor

standard of 280 ppmv. While evaluating

the revised database, we investigated

another data analysis method whereby

floor control would be defined as wet

scrubbing combined with chlorine

feedrate control to achieve an emission

level of 75 ppmv.28 Under this method,
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24225

sources with anomalously high emissions were

screened from consideration. One reason that a

source may have anomalously high emissions is

that it may be feeding unusually high levels of

chlorine.

29The anomalously high emissions could have

been caused by: (1) Poor design, operation, or

maintenance of the scrubber, and thus the device

would not represent MACT (e.g., a dry scrubber was

screened from the analysis because dry scrubbers

are generally less efficient than wet scrubbers); (2)

unusually high chlorine feedrates; or (3) sampling

or analysis anomalies.

30The floor standard under this alternative

analysis method—75 ppmv—would be substantially

lower than the proposed floor standard—280

ppmv—even though feedrate control of chlorine

would not be used explicitly to help define floor

control under this alternative method because, to

identify the proposed standard, the Agency: (1)

Selected as the standard-setting test condition the

highest test condition for sources appearing to be

using floor control without screening anomalous

test conditions; and (2) added a computed

emissions variability factor to emissions from that

standard-setting test condition.

31Considering approximately 50 test conditions

where emissions levels on both HCl and Cl2 were

available.

32Additional details of the engineering and data

analysis evaluations performed on the revised

emissions database can be found in the Agency’s

background document: USEPA, ‘‘Draft Technical

Support Document for HWC MACT Standards

(NODA), Volume I: MACT Evaluations Based on

Revised Database’’, April 1997.

emissions data from sources using wet

or dry scrubbing were arrayed from

lowest to highest (without explicit

regard to chlorine feedrate) and sources

achieving substantially poorer HCl/Cl2

control than other sources were

screened from the analysis.

Accordingly, after five of 48 test

conditions were screened from the

analysis for anomalously high emission

rates,29 the floor standard was

established as the highest remaining test

condition average—75 ppmv.30 Nearly

90 percent of test conditions 31 in the

revised database have emission levels

below 75 ppmv.

The Agency requests comment on

whether this alternative approach to

define floor control and a floor level

would be more appropriate than the

proposed approach.

b. BTF considerations for existing

sources. At proposal, the Agency

determined that a BTF standard would

not be warranted. Specifically, the

Agency noted that risk from emissions

at the floor standard would not likely

trigger the need for additional control

under RCRA.

Although that may prove to be the

case as well for the alternative standard

discussed in today’s notice (i.e., 75

ppmv), the risk assessment

accompanying the final rule will

consider incinerators with short stacks

and will also consider acute risk from

HCl and Cl2 during short-term

exposures. The risk assessment at

proposal modeled emissions only from

incinerators with relatively tall stacks,

and did not consider acute exposure to

HCl and Cl2. If, however, the revised

risk assessment yet to be conducted

shows significant risk at a floor standard

of 75 ppmv, the Agency will determine

whether a BTF standard would be

appropriate considering costeffectiveness of such a standard and the

need to establish more stringent controls

under RCRA. In that case, BTF control

could be based on a minimum system

removal efficiency (e.g., 99.9 percent)

and/or control of chlorine feedrate.

c. MACT floor for new sources. At

proposal, the Agency identified floor

control for new incinerators as wet

scrubbing with an MTEC of 1.7E7 μg/

dcsm See 61 FR at 17388. Although the

floor control for new sources was based

on the single best performing source and

was more stringent than floor control for

existing sources, the floor emission level

was the same for new and existing

sources: 280 ppmv.

When evaluating the revised

emissions database considering various

data analyses methods for today’s

notice, we determined that floor control

for new sources should be the same as

for existing sources: Wet scrubbing with

chlorine feedrate control to achieve an

emission level of 75 ppmv. This is stateof-the-art control for these HAPs.

Accordingly, the floor standard for new

sources would be 75 ppmv under this

data analysis method.

d. BTF considerations for new

sources. The Agency proposed BTF

control for new incinerators as 99

percent SRE and a BTF standard of 67

ppmv. This standard was based on

applying 99 percent reduction to the test

condition in the database with the

highest average emission without an

emission control device (i.e., 1100

ppmv). Then, considering other factors

including a computed emissions

variability factor, the Agency

determined that a BTF standard of 67

ppmv would be appropriate.

In retrospect, as we discussed above,

virtually all sources are already

equipped with some form of scrubber

and 90 percent are achieving emission

levels of 75 ppmv or below. Thus, this

would be an appropriate floor control

and standard for new sources. As

discussed above for existing sources, a

BTF standard appears to be

unnecessary, unless the upcoming final

risk analysis indicates that more

stringent controls under RCRA would be

warranted. A BTF standard could be

based on a minimum system removal

efficiency (e.g., 99.9 percent) and/or

control of chlorine feedrate.

8. Carbon Monoxide (CO). As

proposed, the Agency continues to

believe that floor control for CO (as a

surrogate for organic HAPs) for both

existing and new sources would be

operation under good combustion

practices. The preponderance of the

revised emissions data indicate that a

floor standard of 100 ppmv over an

hourly rolling average (HRA) would be

readily achievable. In addition, the

Agency continues to believe that a BTF

standard for CO based on better good

combustion practices is likely to raise

significant cost-effectiveness

considerations.

9. Hydrocarbons (HC). The Agency

proposed that floor control for HC (as a

surrogate for otherwise unaddressed

organic HAPs) for both existing and new

sources would be operated under good

combustion practices and that a floor

standard of 12 ppmv over an hourly

rolling average (HRA), would be

appropriate. In evaluating the revised

emission database for today’s notice, we

used the same general approach for HC

as at proposal—the entire database was

arrayed from the lowest to the highest

emission levels and assumed that test

conditions beyond a breakpoint were

not operated under good combustion

practices. Based on that analysis, a floor

level for HC of 10 ppmv, HRA, results.

(This 10 ppmv standard does not

include a variability factor for reasons

discussed above, unlike the proposed

standard of 12 ppmv that did.) Not only

does the revised database show that the

preponderance of the data are below 10

ppmv, but engineering experience and

other engineering information suggests

that a HC level of 10 ppmv is readily

achievable using good combustion

practices.

As discussed at proposal, the Agency

continues to be concerned about costeffectiveness considerations related to

BTF controls for HC based on operating

under better combustion practices.

F. Re-Evaluation of Proposed MACT

Standards for Cement Kilns

We discuss in this section the basis

for the revised standards for cement

kilns that result from applying

engineering and data analysis to the

revised emissions database.32 A

comparison of the proposed and

potentially revised standards for

existing and new sources is presented in

the table below:
24226 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

33The standard would be expressed in the form

of a TEQ level combined with a maximum

temperature at the PM control device. This form of

the standard is consistent with the revised data and

would result in somewhat lower emissions (i.e.,

because without the TEQ limit, some sources could

exceed that TEQ level at the specified temperature).

Thus, expressing the standard in this form better

achieves the statutory mandate to establish

standards that provide the maximum degree of

reduction that is achievable in practice.

34We considered whether nonwaste cement kiln

emission data should be pooled with HW cement

kiln data for other HAPs and determined that

emissions of other HAPs, except for PM, could be

affected by hazardous waste burning. For example,

hazardous waste can have higher levels of chlorine

and metals such as Pb. With respect to PM,

although it appears appropriate to pool the data

sets, the better-suited data analysis method is based

on the New Source Performance Standard, not an

analysis of the emissions database. Thus, pooling of

data would not affect the standard derived from that

data analysis method. See discussion on the PM

standard in the text.

TABLE II.F.—REVISED STANDARDS FOR EXISTING AND NEW CEMENT KILNS

HAP or HAP Surrogate

Existing sources New sources

Proposed

standard

Revised

standard

Proposed

standard

Revised

standard

D/F (ng TEQ/dscm) .................................................................................................. 1 0.20 0.20 0.20 0.20

Hg (μg/dscm) ............................................................................................................ 50 72 50 72

PM (gr/dscf) .............................................................................................................. 0.030 0.030 0.030 0.030

HCl/Cl2 (ppmv) ......................................................................................................... 630 120 67 120

CO (ppmv) ................................................................................................................ 100 100 100 100

HC (ppmv):

Main Stack 2 ...................................................................................................... 20 20 20 20

By-Pass ............................................................................................................. 6.7 10 6.7 10

SVM (μg/dscm) ......................................................................................................... 57 670 55 670

LVM (μg/dscm) ......................................................................................................... 130 63 44 63

1All emission levels are corrected to 7% O2. 2 Not applicable to preheater and/or precalciner kilns.

1. Subcategorization considerations.

After analyzing comments submitted by

the Cement Kiln Recycling Coalition

(CKRC) on the proposed rule, including

information on the types of cement kilns

that are currently burning hazardous

waste, we considered whether the

following subcategories would be

appropriate: (1) Short kilns with

separate by-pass and main stacks; (2)

short kilns with a single stack that

handles both by-pass and preheater or

precalciner emissions; (3) long dry kilns

that use kiln gas to dry raw meal in the

raw mill; and (4) others (i.e., wet kilns,

and long dry kilns not using raw mill

drying). Each of the first three categories

is comprised of only one cement kiln

facility while the kilns at the remaining

19 facilities are in the fourth category:

wet kilns or long dry kilns that do not

use raw mill drying. We find that these

subcategories should be considered

because the unique design or operating

features of these kilns could have a

significant impact on emissions of one

or more HAPs that the Agency proposed

to regulate.

To determine whether special

standards would be appropriate for any

of the three unique cement kiln types,

we identified floor control and emission

levels considering data only for the

other kilns (i.e., wet kilns, and long dry

kilns not using raw mill drying). We

then considered whether the unique

kiln types could apply the those MACT

controls and achieve those emission

standards. It appears that these unique

kilns can employ the MACT controls

and achieve the corresponding emission

levels identified in today’s notice for the

other kilns (i.e., wet kilns, and long dry

kilns not using raw mill drying). Thus,

subcategorization would not appear to

be needed to determine achievable

MACT floors for all cement kilns

burning hazardous waste.

2. Dioxins and Furans (D/F). a. MACT

Floor for Existing Sources. At proposal,

the Agency identified floor control as

‘‘temperature control at the inlet to the

ESP or fabric filter at 418 °F’’. The

proposed floor emission level was ‘‘0.20

ng TEQ/dscm, or temperature at the

inlet to the ESP or fabric filter not to

exceed 418 °F’’.

Upon re-evaluation of the revised

database, we have identified an

alternative data analysis method that

seems more appropriate to identify floor

control and the floor emission level.

Based on an engineering evaluation of

these data and other available

information, floor control would be

‘‘temperature control at the inlet to the

ESP or fabric filter at 400 °F’’. This

results in a floor emission level of ‘‘0.20

ng TEQ/dscm, or 0.40 ng TEQ/dscm and

temperature at the inlet to the ESP or

fabric filter not to exceed 400 °F’’.33

Temperature control to 400 °F or

lower is appropriate for floor control

because, from an engineering

perspective, it is within the range of

reasonable values that could have been

selected considering that: (1) The

optimum temperature window for

surface-catalyzed D/F formation is 450–

750 °F; and (2) below 350 °F, kiln gas

can fall below the dew point which can

increase corrosion in ESPs and fabric

filters and reduce performance of the

control devices. In addition,

approximately 20 percent of the test

conditions in our revised database

reflect operations at temperatures of 400

°F or below. Thus, this temperature

level is readily achievable.

To identify an emission level that

temperature control ≤400 °F could

achieve, it is appropriate to pool the

available emissions data for hazardous

waste burning kilns with data from

nonwaste burning kilns.34 This is

because we are not aware of an

engineering reason why hazardous

waste burning would affect emissions of

D/F. In fact, when the data sets are

evaluated separately, the highest

emitting HW cement kiln operating the

ESP or fabric filter at temperatures ≤400

°F had D/F emissions of 0.28 ng TEQ/

dscm. The highest emitting nonwaste

cement kiln operating at those

temperatures had D/F emissions of 0.37

ng TEQ/dscm. We believe that the

difference in emission levels is simply

a reflection of many design, operation,

and maintenance factors on which we

have little or no information, but which

could affect D/F emission levels. An

appropriate emission level associated

with that operating temperature for all

cement kilns would be 0.40 ng TEQ/

dscm. Thus, the floor standard would

be: ‘‘0.20 ng TEQ/dscm, or 0.40 ng TEQ/

dscm and temperature at the inlet to the

ESP or fabric filter not to exceed 400

°F’’.

b. BTF considerations for existing

sources. The Agency proposed a BTF

standard of 0.20 ng TEQ/dscm based on

ACI operated at a temperature of ≤400
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24227

°F. We continue to believe that this BTF

standard is appropriate given the

concerns the Agency has expressed

about the risks posed by D/F emissions,

and the Hg reductions that ACI would

also provide. See 61 FR at 17392. Only

sources emitting between 0.20 and 0.40

ng TEQ/dscm with temperature control

alone would need to take further

measures to reduce D/F levels to 0.20 ng

under the BTF standard. Although these

sources could achieve D/F emission

levels well below 0.20 ng TEQ/dscm

using ACI (i.e., ACI removal efficiency

should be in the 95–99 percent range),

a 0.20 ng TEQ/dscm appears still to be

appropriate because it may allow some

sources to meet the standard more costeffectively by lowering gas temperatures

at the ESP or fabric filter below 400 °F.

Further, a BTF standard of 0.20 ng TEQ/

dscm would likely avoid the need to

provide further controls under RCRA

authority.

c. MACT floor for new sources. At

proposal, the Agency identified floor

control for new sources as ‘‘temperature

control at the inlet to the ESP or fabric

filter at 409 °F’’. The proposed floor

emission level was ‘‘0.20 ng TEQ/dscm,

or temperature at the inlet to the ESP or

fabric filter not to exceed 409 °F’’.

Upon evaluation of the revised

database, the floor control and emission

level discussed above for existing

sources would also be appropriate for

new sources (i.e., ‘‘temperature control

at the inlet to the ESP or fabric filter at

400 °F’’ corresponding to an emission

level of ‘‘0.20 ng TEQ/dscm, or 0.40 ng

TEQ/dscm and temperature at the inlet

to the ESP or fabric filter not to exceed

400 °F’’. This is because our engineering

evaluation of available information and

facility operating experience indicates

that the best controlled source is one

that is controlling temperature control at

the inlet to the fabric filter at 400 °F.

d. BTF considerations for new

sources. The Agency proposed ACI as

BTF control and a BTF standard of 0.20

ng TEQ/dscm. We continue to believe

that this BTF standard is appropriate for

new sources for the same reasons

discussed above in the context of

existing sources.

3. Mercury (Hg). a. MACT floor for

existing sources. At proposal, the

Agency identified floor control as

hazardous waste feedrate control not to

exceed an MTEC of 110 μg/dscm. EPA

proposed a floor standard of 130 μg/

dscm.

All cement kilns employ either ESPs

and fabric filters for PM control.

However, since Hg is generally in the

vapor form in and downstream of the

combustion chamber, including the air

pollution control device, ESPs and

fabric filters do not achieve good

mercury control. Mercury emissions

from cement kilns are currently

controlled by the BIF rule which

establishes limits on the maximum

feedrate of Hg in total feedstreams (e.g.,

hazardous waste, raw materials, coal).

Thus, MACT is based on hazardous

waste feed control.

Review of the revised database

indicate that cement kilns only

infrequently conducted Hg spiking of

the hazardous wastes (contrary to the

Agency’s initial information), and thus

the Hg content in the wastes during

testing is likely representative of the Hg

content during typical operations. The

revised data also show that raw

materials can represent a significant

source Hg input to the kiln system.

Since cement kilns do not employ a

dedicated device capable of Hg control,

the Agency believes that the Hg data are

essentially ‘‘normal’’ even though

generated during worst case compliance

testing conditions for other parameters.

To evaluate these revised data for the

purpose of determining a MACT floor,

the Agency used the following data

analysis steps: (1) Rank Hg emissions

from lowest to highest; (2) conduct a

breakpoint analysis on the ranked Hg

emissions data, and (3) establish the

floor standard as the test condition

average of the breakpoint source. The

breakpoint analysis reflects an

engineering-based evaluation of the data

and ensures that the few cement kilns

spiking extra Hg do not drive the floor

level to levels higher than the

preponderance of this ‘‘normal’’ data

indicates is routinely achievable. The

Agency’s analysis results in a MACT

floor level of 72 μg/dscm. The revised

database indicates that approximately

80 percent of cement kilns are achieving

this floor level.

b. BTF considerations for existing

sources. The Agency proposed a BTF

standard of 50 μg/dscm based on flue

gas temperature reduction to 400 °F or

less followed by ACI. EPA continues to

believe that ACI is an appropriate BTF

technology for cement kilns. Although

ACI is not employed for Hg control at

any full-scale HW cement kiln, the

Agency is not aware of any cement kiln

flue gas conditions that would preclude

the applicability of ACI—which has

been demonstrated for other similar

types of combustion applications. As

discussed in the NPRM, EPA assumes

that cement kilns employing ACI to

meet a BTF standard would install the

ACI system after the existing ESP or

fabric filter, and then add on a new

fabric filter to remove the injected

carbon with the adsorbed Hg. Although

adding a new fabric filter in series is an

expensive approach, it will enable

cement kilns to continue current cement

kiln dust (CKD) recycling practices by

avoiding potential internal build-up of

Hg from CKD recycling.

In the NPRM, the cement kiln BTF

standard was based on the assumption

that an ACI system could routinely

achieve Hg emissions reductions of 80

to 90 percent. The Agency received

public comments from, among others,

the cement manufacturing industry

questioning whether a ACI application

on a cement kiln could routinely

achieve capture efficiencies as

proposed. The commenters went on to

say that removal efficiencies of

approximately 60 percent were perhaps

more realistic. We will address these

comments specifically as part in the

final rulemaking, but for the purposes of

today’s analysis, EPA has assumed an

ACI effectiveness of 60 percent in

identifying BTF levels for cement kilns.

Thus, the BTF standard for cement kilns

would be 30 μg/dscm based on an ACI

efficiency of 60 percent applied to the

potential floor level of 72 μg/dscm.

Ultimately adopting a BTF standard of

30 μg/dscm for cement kilns will likely

involve close scrutiny of costeffectiveness and other factors,

including the costs of retrofits that

sources will need to undertake (e.g.,

installing the ACI system, add-on of a

new fabric filter, managing the captured

carbon) relative to the emissions

reductions achieved. Without prejudging this issue, the Agency’s

experience to date suggests that the final

analysis may well reveal significant

drawbacks associated with the BTF

level.

c. MACT floor for new sources. At

proposal, the Agency identified floor

control for new sources as hazardous

waste feedrate control not to exceed an

MTEC of 28 μg/dscm. EPA proposed a

floor standard of 82 μg/dscm.

The Agency believes that the floor

control and emission level discussed

above for existing sources would also be

appropriate for new sources. Thus, the

MACT floor for new cement kilns would

be 72 μg/dscm based on the revised

database.

d. BTF considerations for new

sources. At proposal, BTF for new

sources was based on ACI and we

proposed a BTF standard of 50 μg/dscm.

As discussed for existing sources, the

Agency is considering the use of ACI

and flue gas temperature reduction to

400 °F as the BTF technology. In

evaluating the revised database, EPA

has identified a level of 30 μg/dscm as

the BTF standard for new sources based

on ACI. This is based on a source

achieving the MACT new floor level of
24228 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

72 μg/dscm and then applying ACI with

a 60 percent removal efficiency. For the

same reasons identified for existing

sources, the Agency is concerned about

whether this BTF level based on ACI

will ultimately prove to be cost-effective

for new cement kiln sources.

4. Particulate Matter (PM). a. MACT

floor for existing sources. At proposal,

EPA defined floor control as a fabric

filter with an air-to-cloth ratio of 2.3

acfm/ft2. The floor analysis led to a level

of 0.065 gr/dscf, but due to concerns

with the appropriateness of using a

statistically-derived variability factor,

the Agency instead established the floor

standard based on the cement kiln New

Source Performance Standard (NSPS).

The NSPS is a process emissions rate

that converts to an approximate flue gas

concentration of 0.03 gr/dscf.

Today, EPA is taking comment on two

data analysis methods to identify the

PM floor standard for cement kilns. The

first data analysis method would be to

establish the floor standard equivalent

to the NSPS, which is 0.3 lbs PM per ton

of dry raw material feed. Currently,

approximately 20 percent of HW cement

kilns are subject to the NSPS. Cement

kilns achieve the NSPS with welldesigned and properly operated ESPs or

fabric filters.

A second data analysis method

considered and potentially preferred

would be to express the NSPS as a stack

gas concentration limit as done in the

NPRM. The conversion of the NSPS to

a concentration standard will vary by

kiln process type (e.g., wet, dry,

preheater, preheater/precalciner)

because the amount of flue gas

generated per ton of raw material feed

varies by process type. Based on typical

factors of flue gas quantities generated

per ton of raw material feed and flue gas

moisture content, the NSPS equates to a

PM concentration of approximately 0.03

gr/dscf for wet process kilns (also the

least energy efficient) and 0.05 gr/dscf

for preheater kilns (the most energy

efficient). The total HW cement kiln

universe is comprised of 41 kilns with

varying process types: 27 wet, 12 long

dry, one preheater/precalciner, and one

preheater. Of the cement kilns currently

subject to the NSPS standard, four are

wet, two are long dry, one preheater/

precalciner, and one preheater.

Notwithstanding that the

concentration equivalent of the NSPS

can vary by process type, establishing

the floor standard for all cement kilns at

0.030 gr/dscf appears to be appropriate

regardless of manufacturing process

utilized, for the following reasons: (1)

The majority (66 percent) of the cement

kilns are wet process kilns for which the

NSPS concentration equivalent is 0.030

gr/dscf. For these kilns, this floor

method would not differ from the initial

NSPS method used in the proposal. (2)

Our database shows non-wet process

kilns have at least one test condition (in

addition to three quarters of all non-wet

process kiln data) achieving 0.030 gr/

dscf. Therefore, achievability of the

floor appears to be satisfied. (3) Even

though wet process kilns typically have

lower inlet grain loadings than the nonwet processes, non-wet kilns are

achieving the 0.030 gr/dscf level. Again,

the achievability requirement is met.

Thus, the Agency believes that it is

appropriate to establish the MACT floor

for existing sources at 0.030 gr/dscf.

In the NPRM, the Agency proposed

that sources maintain continuous

compliance with the PM standard

through the use of a PM CEMS. A

decision whether to require cement

kilns to install a PM CEMS will be made

at the completion of an on-going

demonstration testing program to

determine if at least one PM CEMS can

meet the proposed performance

specifications. Since the floor standards

discussed above were based on manual

test method data, the Agency will reevaluate at the completion of the CEMS

testing program whether these PM floor

standards would be appropriate in the

event that the final rulemaking requires

continuous compliance with a PM

CEMS. The Agency will make available

the results and conclusions of the

demonstration test program in the

docket for the HWC rule.

b. BTF considerations for existing

sources. In the NPRM, the Agency

considered a BTF level of 0.015 gr/dscf

based on improved PM control.

However, we determined that such a

standard would not likely be costeffective. We did not have adequate data

to ensure that, given the high inlet grain

loading caused by entrained raw

material, cement kilns could routinely

achieve 0.015 gr/dscf and below with a

single fabric filter or ESP.

In light of the revised database, the

Agency again considered a BTF PM

emissions level based on improved PM

control. Because the floor level of 0.030

gr/dscf presented today is the same as

the proposed floor, a BTF standard

lower than 0.030 gr/dscf (even with

corresponding BTF reductions for SVMs

and LVMs) appears not to be costeffective based on information

developed at proposal.

c. MACT floor for new sources. At

proposal, the Agency defined floor

control as a fabric filter with an air-tocloth ratio of less than 1.8 acfm/ft2. The

floor analysis lead to a level of 0.065 gr/

dscf. Due to concerns with the

appropriateness of the statisticallyderived variability factor, the Agency

instead established the floor standard

based on the cement kiln NSPS. The

NSPS is a process emissions rate that

the Agency converted to an approximate

flue gas concentration of 0.030 gr/dscf.

Upon evaluation of the revised

database discussed for existing sources,

EPA continues to believe that the floor

standard discussed above for existing

sources would also be appropriate for

new sources. Therefore, MACT floor

control is a well-designed and properly

operated PM control device (e.g., fabric

filter, ESP), and the MACT floor for new

cement kilns would be 0.030 gr/dscf.

d. BTF considerations for new

sources. In the NPRM, EPA considered

a BTF standard based on improved PM

control to be consistent with existing

sources. However, we found that the

BTF level would not be cost-effective.

Today, as discussed above for existing

source BTF considerations and based

upon examining the revised database in

light of the findings at proposal, a BTF

standard beyond a PM level of 0.030 gr/

dscf (and corresponding BTF reductions

for SVMs and LVMs) would not appear

to be cost-effective.

5. Semivolatile Metals (SVM)

(cadmium and lead). a. MACT Floor for

Existing Sources. At proposal, EPA

defined floor control as a fabric filter

with an air-to-cloth ratio less than 2.1

acfm/ft2 and a HW MTEC of 84,000 μg/

dscm. The proposed floor level was 57

μg/dscm.

Cement kilns use a combination of

good PM control and limiting hazardous

waste feedrates to control SVM

emissions. SVMs are controlled most

efficiently by technologies, such as

fabric filters, which are effective at

capturing fine PM. EPA’s database

shows that SVM emissions vary

substantially from 1 to over 6,000 μg/

dscm.

The engineering evaluation and data

analysis method used by EPA to

evaluate and identify a MACT floor

from the revised database is an

extension of the PM floor analyses of the

revised database. As discussed in the

PM analysis, a floor of 0.030 gr/dscf

could represent MACT based on good

PM control. Since SVMs are controlled,

in part, by a well-designed and operated

PM control device, it follows that

sources achieving this PM performance

level should also be controlling SVM

emissions at typical SVM feedrates.

Therefore, in its refined SVM analysis of

the revised database, EPA would first

consider all SVM data when

corresponding PM measurements are

below 0.030 gr/dscf. To identify the

SVM floor from these data, we would

identify the floor at the level that
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24229

excludes (by breakpoint analysis)

sources achieving substantially poorer

SVM control than the majority of

sources. As noted earlier in the case of

HWIs, it is appropriate to exclude

sources with significantly poorer SVM

performance because their higher SVM

emissions may be the result of

exceedingly high SVM feedrates or some

other factor that shows the test

condition did not actually reflect MACT

floor controls. The Agency does not

have available information to otherwise

screen out these non-MACT test

conditions from the expanded universe

for SVM.

The Agency’s evaluation of the

revised cement kiln SVMs data results

in a MACT floor of approximately 670

μg/dscm. Approximately 85 percent of

SVM test condition data are currently

achieving this emissions level.

Finally, as discussed in an earlier

section, a preliminary analysis indicates

that MACT standards may not be

warranted for one HAP metal, antimony.

Since the number of metals being

considered for MACT standards may

change, we are investigating the

appropriate structure of metals

standards (e.g., retain the volatility

groups or establish individual metals

standards). Using the refined method

discussed above for SVM, we analyzed

the revised database with respect to Cd

and Pb data. The floor analysis

corresponding to PM measurements

below 0.030 gr/dscf would result in the

following floor levels: Cd 60 μg/dscm,

and Pb 560 μg/dscm.

b. BTF considerations for existing

sources. In the NPRM, the Agency

considered a BTF standard for SVMs

based on improved PM control below

0.030 gr/dscf. However, the Agency

concluded that a BTF standard would

not be cost-effective given that the SVM

Floor level of 57 μg/dscm alone would

result in an estimated 94 percent SVM

reduction in emissions.

As discussed for PM BTF

considerations, the Agency also reevaluated the possible appropriateness

of using a reduced PM emissions level

based on improved PM control as a BTF

standard (with corresponding BTF

reductions in SVMs and LVMs). Even

though the SVM floor standard is higher

than at proposal, our preliminary

judgment is that significant costeffectiveness considerations will likely

be encountered in a final analysis of

whether to establish a BTF standard for

either SVMs or for Pb or Cd

individually.

If, however, the revised risk

assessment yet to be conducted would

show significant risk at a SVM floor

standard of either 670 μg/dscm, the

Agency will determine whether a BTF

standard based on control of HW SVM

feedrate to levels below those at the

floor would be appropriate. This

feedrate limitation would in turn reduce

SVM emissions. The BTF standard and

the corresponding level of feedrate

control would be dictated by

considerations of cost-effectiveness and

the need to establish more stringent

RCRA-related controls.

c. MACT floor for new sources. At

proposal, the Agency defined floor

control, based on the best performing

source, as a fabric filter with an air-tocloth ratio less than 2.1 acfm/ft2 and a

HW MTEC of 36,000 μg/dscm The

proposed floor level for new cement

kilns was 55 μg/dscm.

Upon evaluation of the revised

database, EPA believes that the floor

control and emission level discussed

above for existing sources for SVMs

would also be appropriate for new

sources. In this event, MACT floor

control would be a well-designed,

operated and maintained PM control

device (i.e., fabric filter or ESP)

achieving the PM floor level of 0.030 gr/

dscf. The Agency’s evaluation of the

revised SVM data results in a MACT

floor of 670 μg/dscm.

Finally, based on the revised

database, individual metal floor levels

for new sources are identical to those for

existing sources. Thus, individual Cd

and Pb standards are: Cd 65 μg/dscm

and Pb 550 μg/dscm.

d. BTF Considerations for new

sources. In the NPRM, the Agency

considered a SVM BTF level, but

determined that a BTF standard would

not be cost-effective.

As discussed for existing sources, the

Agency considered a more stringent PM

emissions level for improved control of

PM, SVM and LVM emissions for new

cement kilns in light of the revised

database. Even though the SVM floor

standard is higher than at proposal, our

preliminary judgment is that significant

cost-effectiveness considerations will

likely be encountered in a final analysis

of whether to establish a BTF standard

for either SVMs or for Pb or Cd

individually.

6. Low Volatile Metals (LVM) (arsenic,

beryllium, and chromium). a. MACT

floor for existing sources. At proposal,

EPA defined floor control as either (1)

a fabric filter with an air-to-cloth ratio

less than 2.3 acfm/ft 2 and a HW MTEC

of 140,000 μg/dscm, or (2) an ESP with

a specific collection area of 350 ft2/

kacfm. The proposed floor level was 130

μg/dscm, which included antimony.

The engineering and data analysis

method used by EPA to evaluate the

revised database and identify a MACT

floor for LVMs is also related directly to

the PM floor analysis. As was

determined in the PM analysis, a floor

of 0.030 gr/dscf represents MACT for

cement kilns based on good PM control.

Considering all LVM data from sources

achieving a PM level 0.030 gr/dscf or

better, EPA’s evaluation of the revised

cement kiln data would result in a LVM

floor of 63 μg/dscm (excluding sources

above a breakpoint and therefore

excluding those with substantially

poorer LVM emissions than the majority

of sources). Approximately 90 percent

of cement kiln LVM test condition data

are currently achieving this emissions

level.

Finally, as discussed for SVMs, EPA

is continuing to investigate the

appropriate structure of metals

standards (e.g., retain the volatility

groups or establish individual metals

standards). The Agency analyzed

individual As, Be, and Cr (hexavalent)

data and established individual metal

floor levels consistent with the

engineering evaluation and data

analysis method. Where PM

measurements are below 0.030 gr/dscf,

the result would be: As 10 μg/dscm, Be

1.1μg/dscm, and Cr (hexavalent) 4.6

μg/dscm.

The Agency is concerned that some of

the potential floor standards for some

individual metals (e.g., Be, Cr

(hexavalent)) may be present at levels

approaching practical quantitation

limits (PQLs). PQLs are the lowest level

of quantification that the Agency

believes a competent analytical

laboratory can be expected to reliably

achieve. The Agency will investigate

whether this issue may need to be

addressed in the development of any

individual metals standards that may be

considered for the final rulemaking. We

invite comment on the issue of PQLs

and LVM BTF standards.

b. BTF considerations for existing

sources. In the NPRM, the Agency

considered a BTF standard for LVMs

based on improved PM control below

0.030 gr/dscf. However, the Agency

concluded that a BTF LVM standard

would not be cost-effective.

As discussed for PM, a reduced PM

emissions level based on improved PM

control could be considered in

evaluating a potential BTF standard

(taking into consideration

corresponding BTF reductions in LVMs

and SVMs) for existing CKs. Because

both the PM and LVM floor levels

presented today would be similar to the

proposed floor, a BTF standard for

either LVMs or individual As, Be, and

Cr (hexavalent) standards based on

improved PM control would likely raise
24230 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

35Or where we had data from fewer than 30

sources, the three sources with the lowest emissions

(i.e., 3 represents the median of the five best

performing sources).

36See previous discussion in the text. As we

discussed at proposal (61 FR at 17396), the

computed variability factor for this standard

resulted in a standard that did not comport with

engineering information on the APCDs at issue,

engineering experience on facility performance

within this source category, or the emissions

database.

37The floor standard without screening the

anomalous SREs would have been 160 ppmv.

significant cost-effectiveness concerns

and may not ultimately be appropriate.

c. MACT floor for new sources. At

proposal, the Agency defined floor

control, based on the best performing

source, as a fabric filter with an air-tocloth ratio less than 2.3 acfm/ft2 and a

HW MTEC of 25,000 μg/dscm. The

proposed LVM floor level for new CKs

was 44 μg/dscm.

Based upon our re-evaluation of the

database, the floor control and emission

level discussed above for existing

sources for LVMs would also appear to

be appropriate for new sources. MACT

floor control is a well-designed and

properly operated PM control device

(i.e., fabric filter, ESP) achieving the PM

floor level of 0.030 gr/dscf. The

Agency’s evaluation of the LVM data

results in a MACT floor of 63 μg/dscm.

Finally, individual metal floor levels

for new sources are identical to those for

existing sources. Thus, the standards

would be: As 10 μg/dscm, Be 1.1 μg/

dscm, and Cr (hexavalent) 4.6 μg/dscm.

d. BTF considerations for new

sources. In the NPRM, the Agency

considered a LVM BTF level, but

determined that a BTF standard would

not be cost-effective.

As discussed for existing sources, the

Agency considered a more stringent PM

emissions level for improved control of

PM, SVM and LVM emissions for new

CKs. Because both the alternative PM

and LVM floor levels presented today

are lower than the proposed floors, a

BTF standard for either LVMs or

individual As, Be, or Cr (hexavalent)

standards based on improved PM

control may be inappropriate in light of

the cost-effectiveness concerns inherent

in this scenario.

7. Hydrochloric Acid and Chlorine

(HCl/Cl2). a. MACT floor for existing

sources. At proposal, the Agency

identified floor control for total chlorine

(i.e., HCl + Cl2) as feedrate control of

chlorine in the hazardous waste at an

MTEC not to exceed 1.6 g/dscm, and

proposed a floor standard of 630 ppmv.

When we evaluated the revised database

prior to today’s notice, we used a data

analysis method similar to that used at

proposal. The floor control would be

defined the same way as proposed, but

the floor standard would be 120 ppmv.

This standard should be readily

achievable given that 93 percent of the

test conditions in the revised database

are meeting that level.

We used the following data analysis

steps for both the proposed standard

and today’s alternative standard: (1)

Rank emissions from lowest to highest;

(2) define as floor control the highest

hazardous waste chlorine MTEC for the

6 percent of sources 35 with the lowest

emissions; and (3) define as the floor

standard the highest test condition

average emissions of any test condition

operated at or below the floor MTEC

(i.e., the expanded universe). We then

refined the data analysis method in two

respects based on an engineering

evaluation of the revised database: (1)

We did not add a computed emissions

variability factor 36; and (2) several test

conditions were deleted from the

expanded universe where an

engineering evaluation revealed that

SREs were significantly worse than the

majority of other SREs.

In the case of total chlorine emissions

for CKs, it appears not to be appropriate

to use a breakpoint analysis to screen

from the expanded universe sources that

are not achieving an appropriate

removal efficiency. This is because total

chlorine is removed incidentally by

reactions with the alkaline raw

materials (e.g., limestone). Thus, it is

difficult to reason that poor SRE is

caused by poor design, operation, or

maintenance of the control system.

Nonetheless, we believe it is still

appropriate to screen out clearly

anomalous SREs because they are likely

indicative of an incorrect MTEC value

or emission measurement. An incorrect

value for either could affect the floor

standard.37

b. BTF considerations for existing

sources. At proposal, the Agency

defined BTF control as wet scrubbing

with a 99 percent removal efficiency,

but determined that a BTF standard

would not be cost-effective. Given that

the alternative floor level presented

today would be substantially lower than

the proposed floor, a BTF standard

would be less cost-effective. Thus, we

believe that our final analysis is likely

to conclude that a BTF standard would

not be warranted.

c. MACT floor for new sources. At

proposal, the Agency defined floor

control for new sources as hazardous

waste feedrate control for chlorine at an

MTEC of 1.6 g/dscm or less. The

proposed floor standard was 630 ppmv,

the same as the floor standard for

existing sources.

Given that the alternative data

analysis method discussed above for

existing sources did not change the

expanded universe, except to screen out

test conditions with anomalous SREs,

MACT floor control and the floor

emission level would be the same as for

existing sources: hazardous waste

feedrate control for chlorine at an MTEC

of 1.6 g/dscm or less, resulting in a floor

standard of 120 ppmv (i.e., after

screening out test conditions with

anomalous SREs).

d. BTF considerations for new

sources. The Agency proposed a BTF

standard for new sources of 67 ppmv

based on wet scrubbing. Given that

under the revised data analysis method

discussed today the floor standard

would be much lower than proposed,

the Agency believes that the economic

impact analysis being conducted in

support of the final rule is likely to raise

significant concerns about costeffectiveness. In that event, the Agency

would promulgate the 120 ppmv floor

standard for new sources.

8. Carbon Monoxide (CO). The

Agency proposed the same MACT floor

standards for CO for existing and new

CKs, and determined that BTF controls

would not be cost-effective. Floor

control was defined for kilns with bypass ducts as operation under good

combustion practices and the standard

was 100 ppmv, HRA, measured in the

by-pass duct. For kilns without a bypass duct (i.e., long wet and dry kilns),

no CO standard was proposed given that

CO levels in the main stack would not

be an indicator of combustion

efficiency. This is because CO can be

generated by process chemistry (i.e.,

dissociation of CO2 to form CO) and

evolution from trace organics in the raw

material feedstocks, as well as from

combustion of fuels.

The Agency continues to believe that

the proposed CO standard for kilns

equipped with a by-pass duct would be

appropriate. However, under one option

being considered for limiting CO (and

HC) emissions, kilns without a by-pass

duct would also be required to comply

with a CO limit based on the level

achieved during the performance test

demonstrating compliance with the HC

limit. See discussion in Part Two,

Section II.C.

Finally, the Agency continues to

believe that a BTF standard for CO

based on better combustion practices is

likely to raise significant costeffectiveness considerations.

9. Hydrocarbons (HC). The Agency

proposed the same MACT floor

standards for HC for existing and new

CKs, and determined that BTF controls

would not be cost-effective. Floor
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24231

38 The Agency did not propose a HC standard for

the main stack of a preheater or preheater/

precalciner kiln. See FR at 17397–8. The Agency is

currently developing MACT standards for nonwaste burning cement kilns, however. Any

standards that the Agency may propose that are

applicable to the main stack of a preheater or

preheater/precalciner non-waste burning kiln may

also be appropriate for the main stack of such

hazardous waste burning kilns.

39 The two kilns operating with by-pass ducts are

Medusa’s facility in Demopolis, AL, and Lone Star’s

facility in Cape Girardeau, MO. We note that

Holnam has a long wet kiln in Clarksville, MO that

has been retrofitted with a mid-kiln sampling port

for purposes of monitoring CO in compliance with

the BIF rule. That monitoring approach would be

acceptable under the MACT rule as well.

40Additional details of the engineering and data

analysis evaluations performed on the revised

emissions database can be found in the Agency’s

background document: USEPA, ‘‘Draft Technical

Support Document for HWC MACT Standards

(NODA), Volume I: MACT Evaluations Based on

Revised Database’’, April 1997.

41All LWAKs currently burning hazardous waste

are equipped with fabric filters.

42The standard would be expressed in the form

of a TEQ level combined with a maximum

temperature at the PM control device. This form of

the standard is consistent with the revised data and

would result in somewhat lower emissions (i.e.,

because without the TEQ limit, some sources could

exceed that TEQ level at the specified temperature).

Thus, expressing the standard in this form better

achieves the statutory mandate to establish

standards that provide the maximum degree of

reduction that is achievable in practice.

control was defined for kilns with bypass ducts as operation under good

combustion practices and the standard

was 6.7 ppmv, based on an hourly

rolling average (HRA and measured in

the by-pass duct. For kilns without a bypass duct (i.e., long wet and dry kilns),

floor control was defined as good

combustion practices and use of raw

materials with relatively low organic

content, and the standard was 20 ppmv,

HRA, measured in the main stack.

In evaluating the revised database for

today’s notice, the 20 ppmv standard

still appears to be appropriate for the

main stack of long kilns 38. When

considering by-pass kilns, however, the

revised database still lacks HC

emissions data for the only two CKs

currently burning hazardous waste in

units equipped with by-pass ducts.

These two sources are complying with

the BIF rules by documenting that CO

levels are below 100 ppmv, HRA. 39

Under one attractive option for

compliance with the CO and HC

standards (i.e., sources would have the

option of complying with either the CO

or HC standard; see discussion in Part

Two, Section II.C), we would expect

that these two sources would continue

to comply with the CO limit. Thus, it

may not be necessary to establish a HC

limit for them. However, given that it

may be prudent to establish a HC limit

for these by-pass kilns, we would

transfer the good combustion practicesbased HC standard for incinerators—10

ppmv, HRA—to these kilns. This is

appropriate because: (1) Good

combustion practices is floor control for

CO and HC for these kilns as well as for

incinerators; and (2) given that the good

combustion practices-based CO

standard is the same for incinerators

and by-pass kilns, the good combustion

practices-based HC standard should also

be the same.

As discussed at proposal, the Agency

continues to be concerned about costeffectiveness considerations related to

BTF controls for HC based on operating

under better combustion practices.

G. Re-Evaluation of Proposed MACT

Standards for Lightweight Aggregate

Kilns

We discuss in this section the basis

for the revised standards for LWAKs

that could result from applying various

engineering evaluation and data

analysis methods to the revised

emissions database 40. A comparison of

the proposed and potentially revised

standards for existing and new sources

is presented in the table below:

TABLE II.G:—REVISED STANDARDS FOR EXISTING AND NEW LWAKS 1

HAP or HAP surrogate

Existing sources New sources

Proposed

standard

Revised

standard

Proposed

standard

Revised

standard

D/F (ng TEQ/dscm) .................................................................................................. 0.20 0.20 0.20 0.20

Hg (μg/dscm) ............................................................................................................ 72 47 72 47

PM (gr/dscf) .............................................................................................................. 0.030 0.022 0.030 0.022

HCl/Cl2 (ppmv) ......................................................................................................... 450 130 62 43

CO (ppmv) ................................................................................................................ 100 100 100 100

HC (ppmv) ................................................................................................................ 14 10 14 10

SVM (μg/dscm) ......................................................................................................... 12 76 5.2 76

LVM (μg/dscm) ......................................................................................................... 340 37 55 37

1All emission levels are corrected to 7% O2.

1. Dioxins and Furans (D/F). a. MACT

floor for existing sources. At proposal,

the Agency had D/F emissions for only

one LWAK and therefore pooled that

LWAK data point with D/F data for CKs

to identify MACT standards.

Consequently, floor control and the

floor emission level for LWAKs were the

same as for CKs. The proposed floor

control was ‘‘temperature control at the

inlet to the fabric filter 41 at 418 °F’’, and

the proposed floor emission level was

‘‘0.20 ng TEQ/dscm, or temperature at

the inlet to the fabric filter not to exceed

418 °F’’. The Agency reasoned that

pooling D/F data for LWAKs and CKs

could be appropriate because both types

of devices are designed and operated

similarly with respect to factors that can

affect surface-catalyzed D/F formation.

Both LWAKs and CKs have high PM

inlet loadings comprised primarily of

entrained raw material and both are

equipped with fabric filters that operate

within the same temperature range.

Commenters on the proposed rule,

however, argued that pooling LWAK

and CK D/F data was inappropriate for

purposes of establishing MACT

standards for LWAKs. Since proposal,

the Agency has obtained D/F emissions

data from two additional LWAK

facilities. These data are included in the

revised emissions database and are used

to identify the alternative standards

presented here.

Based upon evaluation of the revised

LWAK D/F database, our engineering

evaluation of the data and other

information on LWAK performance

suggests the floor control can be

specified as ‘‘temperature control at the

inlet to the fabric filter at 400 °F’’. This

would result in a floor emission level of

‘‘0.20 ng TEQ/dscm, or 4.1 ng TEQ/

dscm and temperature at the inlet to the

fabric filter not to exceed 400 °F’.42

Given that the entire revised database

also comprises the expanded universe

(all sources using floor control) the

highest single run for the test condition
24232 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

43See USEPA, ‘‘Draft Technical Support

Document for HWC MACT Standards (NODA),

Volume I: MACT Evaluations Based on Revised

Database’’, April 1997.

with the highest run average would be

a reasonable floor level from an

engineering perspective. (Note that if

this were a large data set, the floor level

could be identified simply as the

highest test condition average.) This

floor level is more than 40 percent

higher than the highest test condition

average (because of substantial

variability among the runs for that test

condition), and thus appears to be a

level that LWAKs should be able to

meet routinely using floor control.

As discussed for CKs, temperature

control to 400 °F or less is appropriate

for floor control because, from an

engineering perspective, it is within the

range of reasonable values that could

have been selected considering that: (1)

The optimum temperature window for

surface-catalyzed D/F formation is 450–

750 °F; and (2) below 350 °F, kiln gas

can fall below the dew point which can

increase corrosion in fabric filters and

reduce performance of the control

device. In addition, more than three

LWAKs in the revised database were

operated at temperatures of 400 °F or

less (even though we do not have D/F

emissions data for them). Thus, this

temperature level appears to be readily

achievable.

Although only two of the three

LWAKs for which we have D/F

emissions data operated the fabric filter

at 400 °F or lower (the third operated at

417 °F), we have fabric filter operating

data for other LWAKs when performing

emissions testing for other HAPs that

document fabric filter operations at 400

°F or lower. The LWAK whose fabric

filter was operated at 417 °F had lower

D/F emissions than a kiln whose fabric

filter was operated at 400 °F. Thus, even

though our engineering evaluation did

not explicitly include the LWAK whose

fabric filter operated at 417 °F, defining

MACT floor control as ‘‘temperature

control at the inlet to the fabric filter at

400 °F’’ did not result in a lower MACT

floor emission level (i.e., lower than 4.1

ng TEQ/dscm). Rather, doing so ensures

that LWAKs will be operating at floor

levels consistent with sound operational

practices for controlling D/F.

b. BTF considerations for existing

sources. The Agency proposed a BTF

standard of 0.20 ng TEQ/dscm based on

ACI operated at a temperature of ≤400

°F.

Upon evaluation of the revised LWAK

D/F database, LWAKs appear to be able

to achieve a 0.20 ng TEQ/dscm standard

simply by rapidly quenching

combustion gases at the exit of the kiln

to ≤400 °F, and insulating the duct-work

leading to the fabric filter to maintain

gas temperatures and avoid dew point

problems. Although the data are not

conclusive, and further testing is

warranted to confirm this approach, our

engineering evaluation of all available

information indicates that this approach

should be feasible.43 If this approach

proves to be less effective than

anticipated, then ACI can be used to

achieve the BTF standard.

We continue to believe that this BTF

standard is appropriate given the

concerns the Agency has expressed

about the risks posed by D/F emissions.

See discussion regarding a D/F BTF

standard for CKs at 61 FR 17392.

Further, a BTF standard of 0.20 ng TEQ/

dscm would preclude the need to

provide further controls under RCRA

authority.

c. MACT floor for new sources. At

proposal, the BTF considerations for

new LWAKs were the same as for new

CKs, and the proposed standards were

the same.

Upon evaluation of the revised LWAK

D/F database, the floor control and

emission level discussed above for

existing sources would also appear to be

appropriate for new sources (i.e.,

‘‘temperature control at the inlet to the

fabric filter at 400 °F’’ corresponding to

an emission level of ‘‘0.20 ng TEQ/

dscm, or 4.1 ng TEQ/dscm and

temperature at the inlet to the fabric

filter not to exceed 400 °F’’. Our

engineering evaluation indicates that

the best controlled source is one that is

controlling temperature control at the

inlet to the fabric filter at 400 °F.

d. BTF considerations for new

sources. The Agency proposed ACI as

BTF control and a BTF standard of 0.20

ng TEQ/dscm. We continue to believe

that this BTF standard is appropriate for

new sources for the same reasons

discussed above in the context of

existing sources. Note that BTF control,

as for existing sources, would be

defined as rapid quench of kiln gas to

≤400 °F combined with duct insulation,

as required, or ACI operated at ≤400 °F.

2. Mercury (Hg) a. MACT Floor for

existing sources. At proposal, the

Agency identified floor control as

hazardous waste feedrate control not to

exceed an MTEC of 17 μg/dscm. EPA

proposed a floor standard of 72 μg/

dscm.

All LWAKs employ fabric filters and

one source uses a fabric filter and

venturi scrubber to control mercury.

However, since Hg is generally in the

vapor form in and downstream of the

combustion chamber, including the air

pollution control device, fabric filters

alone do not achieve good mercury

control. Mercury emissions from

LWAKs are currently controlled under

the BIF rule, which establishes limits on

the maximum feedrate of Hg in total

feedstreams (e.g., hazardous waste, raw

materials). Thus, MACT is based on

hazardous waste feed control.

Review of the updated Hg data in the

revised database indicate that LWAKs

did not conduct Hg spiking of the

hazardous wastes with the exception of

one facility, and thus the Hg content in

the wastes during testing is likely

representative of typical operations. The

data from this testing also show that raw

materials can represent a significant

source Hg input to the kiln system.

Since the best performing sources,

measured by Hg emissions, do not

employ a dedicated device capable of

Hg control, the Agency believes that the

Hg data are essentially ‘‘normal’’ even

though generated during worst case

compliance testing conditions for other

parameters.

To evaluate these revised data for the

purpose of determining a MACT floor,

the Agency used the following data

analysis steps: (1) Rank Hg emissions

from lowest to highest; (2) conduct a

breakpoint analysis on the ranked Hg

emissions data, and (3) establish the

floor standard equal to the test

condition average of the breakpoint

source. The breakpoint analysis reflects

an engineering evaluation of the data

and ensures that the one source that

spiked elevated quantities of Hg did not

drive the floor level upward to levels

higher than the preponderance of this

‘‘normal’’ data indicates is routinely

achievable. The Agency’s analysis

results in a MACT floor level of 47 μg/

dscm. The revised database indicates

that approximately 75 percent of

LWAKs are achieving this floor level.

b. BTF considerations for existing

sources. The Agency originally

considered a BTF standard based on

flue gas temperature reduction to 400 °F

or less followed by ACI, but determined

that a BTF level would not be

warranted.

EPA continues to believe that flue gas

temperature reduction to 400 °F

followed by ACI is the appropriate BTF

control option for improved Hg control

at LWAKs. As discussed above for

existing CKs, we have assumed an ACI

effectiveness of 60 percent in

identifying BTF levels for LWAKs for

the purposes of today’s analysis. Thus,

the BTF standard is 15 μg/dscm which

is based on a ACI efficiency of 60

percent applied to the floor level of 33

μg/dscm. Going to a BTF standard of 15

μg/dscm for mercury is consistent with

the range examined in the proposal.
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24233

However, at proposal, significant costeffectiveness issues were raised (and

commented extensively on). It is likely

that those same issues would arise here

with respect to a BTF standard of 15 μg/

dscm.

c. MACT floor for new sources. At

proposal, the Agency identified floor

control as hazardous waste feedrate

control not to exceed an MTEC of 17 μg/

dscm—the same as existing sources.

Thus, EPA proposed an identical floor

standard of 72 μg/dscm.

For the same reasons discussed for

existing LWAKs, the Agency believes

that the most appropriate engineering

evaluation and data analysis method to

identify the floor level is identical to the

analysis done for existing sources. Thus,

the MACT Floor standard would be 47

μg/dscm for new LWAKs.

d. BTF considerations for new

sources. The Agency considered a BTF

standard for new sources based on ACI,

but determined that it would not be

cost-effective to adopt the BTF standard.

The Agency continues to consider the

use of ACI as the BTF technology. In

evaluating the revised database, EPA

has identified a level of 15 μg/dscm as

the BTF standard for new sources based

on ACI and flue gas temperature

reduction to 400 °F or less. This is based

on a source achieving the MACT new

floor level of 33 μg/dscm and then

applying ACI with a 60 percent removal

efficiency. Again, in light of the reasons

identified for existing sources, the

Agency has concerns as to whether a

BTF level based on ACI will ultimately

be warranted for new LWAK sources.

3. Particulate Matter (PM). a. MACT

Floor for Existing Sources. At proposal,

EPA defined floor control as a fabric

filter with an air-to-cloth ratio of 2.8

acfm/ft 2. The MACT floor was 0.049 gr/

dscf.

In evaluating the revised database, we

examined a refined engineering

evaluation and data analysis method to

identify a MACT floor. This evaluation

was a four-step process: (1) Rank all PM

emissions data and identify the MACT

floor controls used by the best

performing 6 percent of sources. (2)

Develop the expanded universe to

include all sources employing MACT

control, without further characterizing

MACT control (e.g., air-to-cloth ratio of

the fabric filter) as done in the proposal

because we do not have sufficient data

on the detailed design, operating, and

maintenance characteristics related to

test conditions in the revised database.

Since all LWAKs use fabric filters for

PM control, all test condition data are

included in the expanded universe. (3)

For each PM test condition, evaluate the

corresponding SVM SRE and screen out

sources that have relatively poor SREs

(i.e., outliers above a breakpoint in the

data array), which is an indicator of

poor design, operation, and

maintenance characteristics of the

MACT controls at the source. (4)

Identify the MACT floor equal to the

highest test condition average of all test

conditions in the PM expanded

universe.

The Agency’s evaluation of the LWAK

PM data results in a MACT floor of

0.022 gr/dscf. All LWAK test condition

data are achieving 0.022 gr/dscf.

LWAKs typically operate at higher

stack oxygen concentrations compared

to other combustion systems due to the

LWAK manufacturing process (e.g.,

excess air is forced into the kiln to aid

in the expansion of the raw material

into lightweight aggregate). Typical

stack oxygen concentrations range from

12 to 16 percent, while CKs, for

example, typically range from 3 to 8

percent. Since the standards are

expressed at 7 percent oxygen, the floor

standard of 0.022 gr/dscf would be

equivalent to 0.014 gr/dscf at 12 percent

oxygen and 0.008 gr/dscf at 16 percent

oxygen under the conditions that

LWAKs typically operate.

In the NPRM, the Agency proposed

that sources maintain continuous

compliance with the PM standard

through the use of a PM CEMS. A

decision whether to require LWAKs to

install a PM CEMS will be made at the

completion of an on-going

demonstration testing program to

determine if at least one PM CEMS can

meet the proposed performance

specifications. Since the floor standard

discussed above was based on manual

test method data, the Agency will reevaluate at the completion of the CEMS

testing program whether these PM floor

standards would be appropriate in the

event that the final rulemaking requires

continuous compliance with a PM

CEMS. The Agency will notice the

results and conclusions of the

demonstration test program in the

docket for the HWC rule.

b. BTF considerations for existing

sources. In the NPRM, the Agency

proposed a BTF level of 0.030 gr/dscf

and solicited comment on an alternative

BTF level of 0.015 gr/dscf based on

improved PM control.

Based on the revised database, we can

evaluate a reduced PM emissions level

lower than 0.022 gr/dscf as the BTF

standard (in conjunction with BTF

reductions in SVMs and LVMs). This

would require an improved PM

collection technology such as the use of

more expensive fabric filter bag

material. Given that the alternative floor

level analysis presented today would be

substantially lower than the proposed

floor and BTF levels, significant costeffectiveness considerations come into

play and suggest that BTF levels may

not ultimately prove to be warranted.

c. MACT floor for new sources. At

proposal, EPA defined floor control for

new sources as a fabric filter with an airto-cloth ratio of 1.5 acfm/ft 2. The MACT

floor was 0.054 gr/dscf.

Based upon evaluation of the revised

database, the floor control and emission

level discussed above for existing

sources would also appear to be

appropriate for new sources. Therefore,

MACT floor control is a well-designed

and properly operated fabric filter, and

the MACT floor for new LWAKs is 0.022

gr/dscf.

d. BTF considerations for new

sources. In the NPRM, EPA proposed a

BTF standard of 0.030 gr/dscf based on

improved PM control, which was

consistent with existing sources.

Today, as discussed above for existing

source BTF considerations and based

upon examining the revised database in

light of the findings at proposal, a BTF

standard for new sources beyond 0.022

gr/dscf (and corresponding BTF

reductions for SVMs and LVMs) would

not appear to be cost-effective.

4. Semivolatile Metals (SVM)

(cadmium and lead). a. MACT floor for

existing sources. At proposal, EPA

defined floor control as either (1) a

fabric filter with an air-to-cloth ratio of

1.5 acfm/ft 2 with a hazardous waste

(HW) MTEC less than 270,000 μg/dscm,

or (2) a combination of a fabric filter and

venturi scrubber with an air-to-cloth

ratio of 4.2 acfm/ft 2 and a HW MTEC

less than 54,000 μg/dscm. The proposed

floor level was 12 μg/dscm.

LWAKs use a combination of good

PM control and limiting hazardous

waste feedrates to control SVM

emissions. SVMs are controlled most

efficiently by technologies which are

effective at capturing fine PM, such as

fabric filters which are employed by all

LWAKs. EPA’s revised database shows

that SVM emissions vary substantially

from 3 to over 1600 μg/dscm with 60

percent below 80 μg/dscm and the

remaining 40 percent above 400μg/

dscm.

The refined data analysis method

used by EPA to evaluate and identify a

MACT floor would be based directly on

the results from the PM floor analyses

discussed above. As mentioned there,

0.022 gr/dscf would appear to represent

the MACT floor for LWAKs based on

good PM control. Since SVMs are

controlled, in part, by a well-designed

and operated PM control devices, it

follows that sources achieving this PM
24234 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

performance level should also be

controlling SVMs emissions.

Therefore, in its refined SVM analyses

of the revised database, the Agency

would first consider all SVM data when

corresponding PM measurements are

below 0.022 gr/dscf. To identify the

SVM floor from these data, we identify

either at the highest SVM test condition

average or the level that excludes

sources achieving substantially poorer

SVM control than the majority of

sources. It is most likely appropriate to

use the latter approach—excluding

sources with significantly poorer SVM

performance—because their higher SVM

emissions may be the result of

exceedingly high SVM feedrates or some

other factor which is not able to be

discerned from the data available to the

Agency. An SVM emissions breakpoint

analysis is the approach for excluding

these poorer performing test conditions.

Applying this evaluation technique to

the revised LWAK SVM database results

in a MACT floor of 76 μg/dscm.

Approximately 62 percent of LWAK

SVM test condition data are currently

achieving this emissions level.

Finally, as discussed in an earlier

section, a preliminary analysis indicates

that MACT standards may not be

warranted for one HAP metal, antimony.

Since the number of metals being

considered for MACT standards may

change, we are investigating the

appropriate structure of metals

standards (e.g., retain the volatility

groups or establish individual metals

standards). Using the refined method

discussed above for SVM, we analyzed

the revised database with respect to Cd

and Pb data. The floor analysis

corresponding to PM measurements

below 0.022 gr/dscf would result in the

following floor levels: Cd 53 μg/dscm,

and Pb 67 μg/dscm.

b. BTF considerations for existing

sources. In the NPRM, the Agency

considered a BTF standard for SVMs

based on improved PM control.

However, the Agency concluded that a

BTF standard would not be costeffective given that the SVM floor level

of 12 μg/dscm alone would result in an

estimated 97 percent SVM reduction in

emissions.

As discussed for PM BTF

considerations, the Agency also reevaluated the possible appropriateness

of using a reduced PM emissions level

based on improved PM control as a BTF

standard (with corresponding BTF

reductions in SVMs and LVMs). Even

though the alternative SVM floor

standard is higher than at proposal, our

preliminary judgement is that

significant cost-effectiveness

considerations will be nonetheless

encountered in a final analysis of

whether to establish a BTF standard for

SVMs or for Pb or Cd individually.

If, however, the revised risk

assessment yet to be conducted would

show significant risk at a SVM floor

standard of 76 μg/dscm, which would

be the floor level resulting from

application of the data analysis method

discussed above, the Agency will

determine whether a BTF standard

based on control of SVM feedrate to

levels below those at the floor would be

appropriate. This feedrate limitation

would in turn reduce SVM emissions.

The BTF standard and the

corresponding level of feedrate control

would be dictated by considerations of

cost-effectiveness and the need to

establish more stringent RCRA-related

controls.

c. MACT floor for new sources. At

proposal, EPA defined floor control as a

fabric filter with an air-to-cloth ratio of

1.5 acfm/ft 2 with a hazardous waste

(HW) MTEC less than 270,000 μg/dscm.

The proposed floor level was 5.2 μg/

dscm.

Upon evaluation of the revised

database, EPA believes that the floor

control and emission level discussed

above for existing sources for SVMs

would also be appropriate for new

sources. In this event, MACT floor

control would be a well-designed,

operated and maintained PM control

device (e.g., fabric filter) achieving the

PM floor level of 0.022 gr/dscf. The

Agency’s evaluation of the SVM data

results in a MACT floor of 76 μg/dscm.

Finally, based on the revised

database, individual metal floor levels

for new sources are identical to those for

existing sources. Thus, individual Cd

and Pb standards are 53 μg/dscm for Cd

and 67 μg/dscm for Pb.

d. BTF considerations for new

sources. In the NPRM, the Agency

considered a SVM BTF level, but

determined that a BTF standard would

not be cost-effective.

As discussed for existing sources, the

Agency considered a more stringent PM

emissions level for improved control of

PM, SVM and LVM emissions for new

LWAKs in light of the revised database.

Even though the SVM floor standard is

higher than at proposal, as discussed

above, cost-effectiveness issues are

again raised and suggest that a BTF

standard for either SVMs or for Pb or Cd

individually based on improved PM

control may likewise ultimately prove to

be inappropriate.

5. Low Volatile Metals (LVM) (arsenic,

beryllium, and chromium) a. MACT

Floor for Existing Sources. At proposal,

EPA defined floor control as a fabric

filter with an air-to-cloth ratio of 1.8

acfm/ft 2 with a HW MTEC less than

46,000 μg/dscm.

The proposed floor level was 340 μg/

dscm, which included antimony.

LWAKs use a combination of good

PM control and limiting hazardous

waste feedrates to control LVM

emissions. LVMs are less likely to

vaporize at combustion temperatures

and therefore partition primarily to the

residue or adsorb onto particles in the

combustion gas. EPA’s database shows

that LVM emissions vary from around

20 to 285 μg/dscm.

The engineering evaluation data

analysis method used by EPA to

evaluate the revised database and

identify a MACT floor for LVMs is also

related directly to the PM floor analysis.

As was determined in the PM analysis,

a floor of 0.022 gr/dscf represents MACT

for LWAKs based on good PM control.

Considering all LVM data from sources

achieving a PM level 0.022 gr/dscf or

better, EPA’s evaluation of the revised

LWAK data results in a LVM floor of 37

μg/dscm (excluding sources above a

breakpoint and therefore achieving

substantially poorer LVM emissions

than the majority of sources).

Approximately 71 percent of LWAK

LVM test condition data are currently

achieving this emissions level.

Finally, as discussed for SVMs, EPA

is continuing to investigate the

appropriate structure of metals

standards (e.g., retain the volatility

groups or establish individual metals

standards). The Agency analyzed

individual As, Be, and Cr (hexavalent)

data and established individual metal

floor levels consistent with the

engineering evaluation and data

analysis method. Where PM

measurements are below 0.022 gr/dscf,

the result would be: As 22 μg/dscm, Be

3 μg/dscm, and Cr (hexavalent) 6.2 μg/

dscm.

The Agency is concerned that some of

the potential floor standards for some

individual metals (e.g., Be, Cr

(hexavalent)) may be present at levels

approaching practical quantitation

limits (PQLs). PQLs are the lowest level

of quantification that the Agency

believes a competent analytical

laboratory can be expected to reliably

achieve. The Agency will investigate

whether this issue may need to be

addressed in the development of any

individual metals standards that may be

considered for the final rulemaking. We

invite comment on the issue of PQLs

and LVM BTF standards.

b. BTF considerations for existing

sources. In the NPRM, the Agency

considered a BTF standard for LVMs

based on improved PM control.

However, the Agency concluded that a
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24235

44 See discussion in Part Two, Section II.D.

BTF standard would not be costeffective.

As discussed for PM BTF

considerations, the Agency also reevaluated the possible appropriateness

of using a reduced PM emissions level

based on improved PM control as a BTF

standard (with corresponding BTF

reductions in SVMs and LVMs).

Considering that the alternative LVM

floor standard would be lower than at

proposal, our preliminary judgment is

that significant cost-effectiveness

considerations will likely be

encountered in a final analysis of

whether to establish a BTF standard for

either LVM or for As, Be, or Cr

(hexavalent) individually.

c. MACT floor for new sources. At

proposal, EPA defined floor control as a

fabric filter with an air-to-cloth ratio of

1.3 acfm/ft 2 with a hazardous waste

(HW) MTEC less than 37,000 μg/dscm.

The proposed floor level was 55 μg/

dscm.

Based upon our re-evaluation of the

database, the floor control and emission

level discussed above for existing

sources for LVMs would also appear to

be appropriate for new sources. MACT

floor control is a well-designed and

properly operated PM control device

(i.e., fabric filter) achieving the PM floor

level of 0.022 gr/dscf. The Agency’s

evaluation of the LVM data would result

in a MACT floor of 37 μg/dscm.

Finally, individual metal floor levels

for new sources are identical to those for

existing sources. Thus, the standards

would be: As 22 μg/dscm, Be 3 μg/dscm,

and Cr (hexavalent) 6.2 μg/dscm.

d. BTF considerations for new

sources. In the NPRM, the Agency

considered a LVM BTF level, but

determined that a BTF standard would

not be cost-effective.

As discussed for existing sources, the

Agency considered a more stringent PM

emissions level for improved control of

PM, SVM and LVM emissions for new

LWAKs. Because the alternative PM and

LVM floor levels presented today are

lower and approximately equivalent,

respectively, than the proposed floors, a

BTF standard for either LVMs or

individual As, Be, or Cr (hexavalent)

standards based on improved PM

control may be inappropriate in light of

the cost-effectiveness concerns inherent

in this scenario.

6. Hydrochloric Acid and Chlorine

(HCl/Cl2) a. MACT floor for existing

sources. At proposal, the Agency

identified floor control for total chlorine

as either: (1) Hazardous waste feedrate

control of chlorine to a MTEC of 1.5 g/

dscm or less; or (2) venturi scrubber

with hazardous waste MTEC of 14 g/

dscm or less. The proposed floor

emission level was 2100 ppmv.

Upon evaluation of the revised

database, the data analysis method used

at proposal appears still to be

appropriate and, consequently, floor

control would be defined virtually the

same as at proposal. However, EPA no

longer thinks it appropriate to add a

computed emissions variability factor to

the standard-setting test condition for

large data sets 44. Thus, the floor

emission level would be 1300 ppmv

rather than 2100 ppmv.

b. BTF considerations for existing

sources. At proposal, the Agency

defined BTF control as wet or dry lime

scrubbing with a control efficiency of 90

percent and proposed a BTF standard of

450 ppmv.

The Agency continues to believe that

wet or dry lime scrubbing can achieve

at least 90 percent removal of HCl/Cl2.

Therefore, the revised BTF standard

would be 130 ppmv assuming that the

requisite cost-effectiveness information

continues to suggest that a BTF standard

is warranted. The two LWAKs that are

equipped with wet scrubbers achieved

emission levels below 45 ppmv.

c. MACT floor for new sources. At

proposal, the Agency defined MACT

floor control for new sources as a

venturi scrubber with a hazardous waste

MTEC of 14 g/dscm or less, and

identified a floor level of 62 ppmv.

As for existing sources, the data

analysis method used at proposal for

new sources is appropriate and,

consequently, floor control for new

sources would be defined the same as at

proposal. Excluding a computed

emissions variability, the floor emission

level would be 43 ppmv rather than 62

ppmv.

d. BTF considerations for new

sources. The Agency did not propose a

BTF standard for new sources because

the floor standard was based on best

available control technology: wet

scrubbing. We have no new information

in the revised database that would

indicate that this conclusion at proposal

should be revisited.

7. Carbon Monoxide (CO). The

Agency proposed a MACT standard for

CO of 100 ppmv based on a hourly

rolling average (HRA). We continue to

believe that this standard is appropriate

for the reasons expressed in the

preamble to the proposal.

8. Hydrocarbons (HC). The Agency

proposed a HC level of 14 ppmv based

on floor control using good combustion

practices. Although we continue to

believe that floor control is good

combustion practices, our engineering

evaluation of the revised database

suggests that a floor standard of 10

ppmv, HRA, may be more appropriate.

The single LWAK facility in the revised

emissions database that could not

achieve a HC standard of 10 ppmv

(perhaps because of trace organics in the

raw material) has stopped burning

hazardous waste. Data from that facility

have been excluded in the revised

analysis. Although the remaining

LWAKs appear to be able to meet a HC

standard on the order of 6 ppmv, it may

be more appropriate to establish the

standard at 10 ppmv. This is because we

are not aware of an engineering reason

that LWAKs using good combustion

practices should be able to achieve

lower HC emissions than incinerators.

Given that the incinerator HC standard

would be 10 ppmv, that standard also

appears to be appropriate for LWAKs.

Part Three: Implementation

I. Compliance Date Considerations

The Agency proposed that all sources

subject to the final rule be in

compliance with the final standards

three years following the effective date

of the rule (61 FR 17416). The proposed

compliance period is consistent with

the CAA, which defines the maximum

compliance period for sources regulated

under the statute as three years, with the

possibility of a one-year extension for

those sources that adequately

demonstrate a need for additional time

for the installation of emission controls.

The Agency proposed the maximum

compliance period allowed by the Act

because this rule will likely require the

majority of units, currently operating

under RCRA regulations, to undergo

substantial modifications to come into

compliance with the potentially more

stringent final MACT standards.

The general provisions of 40 CFR Part

63 do not require a demonstration of

compliance until 240 days following the

compliance date. This 240 day period

between the compliance date and the

demonstration of compliance is clearly

not appropriate for HWCs because these

devices are presently regulated under

RCRA via enforceable operating limits,

and in this interim period the

enforceable operating limits would be

undefined (61 FR 17415).

Therefore, to provide consistency

with the currently-applicable RCRA

regulatory compliance scheme, the

Agency departed from the general

requirements applicable to MACT

sources and proposed a revised

definition of compliance date. The

proposed definition of compliance date

would require sources to complete

installation of controls and to
24236 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

45 In the HWC proposed rule, however, the

Agency allowed sources 90 days to submit test

results because D/F analyses can require more time

than traditional MACT analyses. We continue to

believe that this 90-day allowance is appropriate.

46The Agency notes that under this scheme

facilities are still subject to the RCRA emission

limitations, and the associated operating limits and

enforcement actions until removal of the air

emission limitations from the RCRA permit.

However, because on the compliance date all

facilities must be compliance with the emission

standards of the final MACT rule, the Pre-COC

operating limits, which are expected to be more

stringent than current RCRA emission standards,

take precedence over the RCRA permit limits except

where the RCRA permit limits are based on a more

stringent standard adopted under the Omnibus

provisions of RCRA section 3005. Furthermore, EPA

notes that compliance with Pre-COC operating

limits that are based on standards that are more

stringent than RCRA emission standards assures

compliance with the RCRA based emission

standards.

successfully complete performance

testing and certify compliance within

the three-year compliance period, not by

a date 240 days after the three-year

compliance period. Id. In addition to the

revised definition of compliance date,

the Agency also proposed a number of

extra consequences for HWC sources

that are not in compliance by the

compliance date: (1) Immediate

termination of waste-burning activities;

(2) loss of RCRA permit or interim

status; (3) a requirement to obtain a new

RCRA permit; and (4) compliance with

MACT standards for new sources.

In response to the proposal, the

Agency received comments suggesting

the three-year compliance period would

be impossible to meet due to a number

of competing factors, and that more time

would be necessary to comply with the

rule. These factors included permit

modification, installation of controls,

and documentation of compliance.

Furthermore, commenters expressed

serious concerns about combining these

factors with the consequences of

missing the compliance date. Industry

commented that under this proposed

approach facilities engaged in legitimate

efforts to comply with the standards

would be forced to terminate wasteburning activities, and be subjected to

burdensome consequences that are

unnecessary to protect the environment

or ensure the public’s safety.

However, EPA has become persuaded

by commenters concerns regarding the

ability of HWC sources in particular to

comply with the proposed standards by

the compliance date. Sources will have

to modify their RCRA permits. Further,

some sources may choose to pursue

waste minimization strategies. For these

reasons, the Agency is considering

certain actions that may be finalized in

advance of the final HWC rule such as,

the streamlined permit modification

procedures discussed at 17455 in the

proposal; as well as, the waste

minimization option for extension of the

compliance date to allow for the

application of waste minimization

controls to meet the final standards

discussed at 17417. The streamlined

permit modification procedures would

reduce the administrative requirements

and time necessary to begin

modification procedures required to

comply with the final standards. The

waste minimization compliance date

extension option, which provides an

additional avenue for facilities to

request an extension of the compliance

date, would afford facilities that choose

to institute waste minimization

measures an additional year to complete

these actions.

However, even with the special

provisions under consideration, sources

may require the full amount of time

allowed under the CAA to comply.

Therefore, the Agency is also

considering a revised implementation

scheme that will allow for a simplified

approach consistent with the

implementation of general CAA-MACT

rules. This approach would provide

both additional relief to sources

complying with the final rule, and

information regarding a source’s

compliance status on the compliance

date for the Agency. The specifics of

this new option are explained in greater

detail in the following paragraphs.

Comments are requested on this new

approach to implementing the HWC

MACT standards.

A. Definition of Compliance Date

Today, the Agency is considering a

revision to the proposed definition of

compliance date. Under this revised

approach, HWC sources would follow

the CAA-MACT schedule for

demonstration of compliance, through

MACT performance testing and

submission of test results, contained in

§ 63.7. Under that section, affected

sources must conduct performance tests

within 180 days following the

compliance date, and submit the results

of the tests 60 days following the

completion of the performance test.45

This CAA-based approach responds to

the comments questioning our revised

definition of compliance date and

would achieve a more consistent

implementation framework. However,

because the Agency is concerned about

the compliance status of affected

sources on the compliance date, the

Agency also seeks comment on

provisions to enhance the general

requirements for HWCs with a

requirement for the submission of a

‘‘precertification of compliance’’ in the

final rule. A precertification of

compliance would require facilities to

precertify their compliance status on the

compliance date. The details of the

precertification of compliance are

described in greater detail in the

following paragraphs.

B. Pre-Certification of Compliance

Today the EPA is seeking comment on

an option which would require sources

to submit a notification to regulatory

agencies that details the operating limits

a unit will be operated under in the

interim period following the compliance

date but before the results of the initial

comprehensive performance test are

submitted. This notification, the

precertification of compliance, would

include all of the information necessary

to determine the compliance status of an

affected source (e.g., automatic waste

feed cutoff limits, feedrate limits,

emission control device operating

limits, etc.) during the 240 day period

after the compliance date. At a

minimum, the facility would be

required to establish operating limits on

all of the parameters identified in the

proposed monitoring requirements

found in table V.2.1 at 17419 of the

proposed rule. This approach is

appropriate because these facilities are

already regulated under RCRA. There

should not be any ambiguity for these

facilities in terms of being between

regulatory regimes at any point in time.

The operating limits in the

precertification of compliance would be

enforceable limits.46 However, if

following the initial comprehensive

performance test, the facility’s

precertification of compliance

designated operating limits are found to

have been inadequate to ensure

compliance with the MACT standards,

the facility will not be deemed out of

compliance with the MACT emissions

standards. EPA invites comment on this

approach, and specifically invites

comment on the necessity of

establishing operating limits on the

entire set of parameters identified in

table V.2.1.

C. Consequences of Non-compliance

As mentioned earlier, the Agency

proposed a number of serious

consequences that would befall a source

that misses the compliance date (61 FR

17416). The Agency proposed these

consequences to provide an incentive

for affected sources to move swiftly to

comply with the final standards. In

response to the proposal, through

written comments from industry and

during round table discussions with
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24237

47We are also evaluating another option whereby

compliance with the HC limit would be required,

and a site-specific CO limit (but not lower than 100

ppmv, the proposed MACT standard) would also be

established. This option would provide assurance

that HC emissions are within allowable levels, and

by also limiting CO, it would give the operator

advance notice of a potential increase in HC levels,

thus helping to avoid an exceedance of the HC

standard.

affected parties, the Agency received

information suggesting that imposition

of these consequences through

regulatory language was unnecessary.

Consequently, the Agency is

considering deleting those specific

consequences from the regulatory

language and relying on the regulating

agency’s policy regarding enforcement

response to govern the type of

enforcement response at a facility that

fails to meet the compliance deadline.

Upon review of this enforcement

process, the Agency is presently

inclined to apply the normal CAA

enforcement procedures to noncompliant sources in the final rule for

hazardous waste combustors.

II. Compliance Requirements

In this section, we discuss several

compliance issues: (1) Compliance with

carbon monoxide (CO) and/or HC

emission standards; (2) compliance with

a startup, shutdown, and malfunction

plan when not burning hazardous

waste; (3) metals extrapolation and

interpolation considerations; (4) sitespecific variances for cement kilns and

LWAKs because of inability to meet the

standards solely due to metals or

chlorine in raw materials; and (5)

emissions averaging for cement kilns

with unique design or operating

features.

A. Compliance With CO and/or HC

Emission Standards

The Agency proposed MACT

emission standards for both CO and HC

for incinerators and LWAKs as

surrogates to control emissions of

organic HAPs. Cement kilns would be

required to comply with either a CO or

HC standard because of raw material

considerations. See 61 FR at 17375–6.

The Agency explained that relying on

only CO or HC alone appeared to have

drawbacks, and thus proposed that

incinerators and LWAKs comply with

emissions standards for both.

Nonetheless, the Agency acknowledged

that requiring compliance with

standards for both CO and HC may be

unnecessarily redundant, and requested

comment on the following alternative

approaches: (1) Giving sources the

option of complying with either CO or

HC; or (2) establishing a MACT standard

for either CO or HC, but not both.

Although the Agency is continuing to

evaluate comments and options 47 on

how to limit CO and/or HC to control

organic HAPs, we invite comment on an

additional feature of the first option

whereby a source can elect to comply

with either the CO or HC standard.

Under this approach, a source that

elects to comply with the CO standard

(rather than the HC standard) would be

required to document during the

performance test compliance with the

HC limit. This is necessary because we

have some (limited) data that show a

source can have HC levels exceeding the

standard discussed in today’s notice

while meeting the CO limit. Even

though the vast majority of the data

indicate that HC will be low when CO

levels are low, a requirement to confirm

this relationship on a site-specific basis

may be warranted.

To confirm the relationship during

the performance test, the source would

use a portable HC monitor to document

that HC levels are below the MACT

standard. This is not expected to be a

burdensome test. Further, however, to

ensure that the CO/HC relationship is

maintained over the range of operating

conditions that the facility may

ultimately employ, we are considering

whether to require the source to

establish limits on key operating

parameters than can affect combustion

efficiency (and thus HC emissions). The

limits would be established based on

parameter values observed while

demonstrating the CO/HC relationship

during the performance test.

We specifically request comment on

which key parameters should be limited

to ensure that the CO/HC relationship is

maintained. Further, we request

comment on whether these key

parameters should be identified on a

national basis or a site-specific basis

during review of the performance test

protocol. In providing comment, note

that the Agency has already proposed to

establish site-specific limits on several

combustion-related parameters to

ensure compliance with the D/F

emission standard (e.g., minimum

combustion chamber temperature;

maximum waste feedrate; and for batch

fed units, maximum batch size and

feeding frequency, and minimum

oxygen concentration in the combustion

gas). In addition, note that it may be

appropriate to identify as key

parameters (for purposes of ensuring

that the CO/HC relationship is

maintained) those parameters for which

limits are currently established during

destruction and removal efficiency

(DRE) testing, including: (1) Minimum

combustion temperature at each

combustion chamber or feed location;

(2) minimum combustion gas residence

time (i.e., maximum combustion gas

velocity, or appropriate surrogate); and

(3) minimum combustion gas oxygen

concentration. If the Agency determines

that DRE testing is not necessary for

some types of sources as discussed in

Section III below, testing to document

the CO/HC relationship would be used

to establish limits on these heretofore

DRE-limited parameters.

B. Startup, Shutdown, and Malfunction

Plans

The Agency proposed that startup,

shutdown and malfunction plans are

not necessary for hazardous waste

combustion sources because the

allowances that such plans provide are

not appropriate for hazardous waste

combustors (61 FR 17449). Specifically,

the Agency stated that EPA did not need

information regarding how quickly a

source is able to correct a malfunction

to come back into compliance with the

standards because affected sources

cannot burn waste unless the source is

in compliance with all applicable

standards.

However, in comments, the Agency

was informed of a few situations in

which it is appropriate for sources to

comply with a startup, shutdown, and

malfunction plan. These situations

include those in which sources

temporarily stop burning hazardous

waste but intend to resume burning

hazardous waste in the near future. The

examples presented to the Agency

involve production units (i.e., cement

kilns, LWAKs, and possibly on-site

incinerators equipped with waste heat

boilers to generate steam or heat at a

chemical production facility) that must

continue operations following waste

feed cutoff to maintain production at the

facility. Also, commenters cited

temporary shutdowns necessary for

planned maintenance to be performed

on the unit.

In light of these comments, the

Agency is rethinking its proposed

approach and requests comment on a

requirement for sources to comply with

the provisions listed in § 63.7 regarding

startup, shutdown and malfunction

plans, including the reporting

requirements of § 63.10(d)(5)(I). These

provisions would apply at HWCs when

waste is not being fed or does not

remain in the combustor, excluding

automatic waste feed cutoff events.

Sources would be subject to the

standards at all times, and the

malfunction plan would only apply

during times when the source is either

temporarily not burning waste or when
24238 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

48This situation would be considered a violation

unless the source can document that the

exceedance occurred after waste was no longer in

the combustor and the residuals of the waste

combustion process had been treated by the

pollution control equipment.

49See USEPA, Draft Technical Support Document

for HWC MACT Standards (NODA), Volume III:

Evaluation of Metal Emissions Database to

Investigate Extrapolation and Interpolation Issues,

April 1997.

50Extrapolations would be based on applying a

conservative ‘‘universal variability factor’’ (UVF)

multiplier to the test condition average. The UVF

is based on evaluating within-test condition

emissions variability for each metal in the Agency’s

trial burn and BIF certification of compliance metal

emissions database. It represents (in log form) a

‘‘residual’’ level that 95 percent of the residual

population is below, where the residual is defined

as the difference between the log of the emission

level for each test condition run and the log of the

test condition average. The UVF would range from

3x to 5x depending on the volatility grouping for

the metal. Given the conservatism of the UVF, a less

conservative approach would be used (i.e., melding

extrapolating using the UVF with extrapolating

from the highest run in a test condition) to

extrapolate to feedrate and emission levels close to

levels actually tested.

51Under the extrapolation approach, sources

would be required to feed metals at no less than

normal rates to narrow the amount of extrapolation

sought. Further, we expect that some spiking would

be desired to increase confidence in the measured

feedrate levels that will be used to project higher

allowable feedrates (i.e., the errors associated with

sampling and analyzing heterogeneous

wastestreams can be minimized by spiking known

quantities). However, the Agency does not want

sources to extrapolate to allowable feedrates that are

significantly higher than their historical range of

feedrates (i.e., extrapolated feedrates should be

limited close to the historical levels that a source

actually fed). This may work to limit the practical

utility of extrapolation.

52To achieve operational flexibility due to

practical testing and compliance restrictions.

waste no longer remains in the

combustor. For example, if a source is

temporarily not burning waste and a

malfunction occurs that is followed by

an exceedance of an applicable

standard, the source will not be in

violation as long as it is complying with

the procedures outlined in the

malfunction plan. On the other hand, if

a source is burning waste and a

malfunction occurs that necessitates an

automatic waste feed cutoff followed by

an exceedence of a standard, the source

would be in violation regardless of

whether the source is complying with

the malfunction plan.48

Therefore, under this option, a source

may develop a malfunction plan that

details the situations in which the

source is intentionally not feeding

waste, or that details the situations

when certain emission control devices

will not be in operation.

C. Metals Extrapolation and

Interpolation Considerations

In the NPRM, the Agency discussed

the operating conditions under which a

source will likely operate to

demonstrate compliance with the metals

emission limits identified in the

proposed rule (61 FR at 17428–30). The

Agency also acknowledged in the

proposal that operators will likely want

to operate their units during

comprehensive performance tests close

to the edge of the operating envelope so

that they can comply with the emission

standards and still achieve the

necessary operational flexibility

required by the facility. EPA further

stated that, to achieve a sufficient level

of operational flexibility, sources could

be expected to engage in the spiking of

metals into the waste matrix, which is

a practice that concerns the Agency.

EPA’s concern extends to the overall

metals loading to the environment (for

example, Hg and Pb), exposure of

facility employees, and exposure of

surrounding community to higher than

normal metals concentrations due to

testing procedures that are for the

purposes of developing waste feedrate

limits and operational flexibility.

Therefore, the Agency has

investigated approaches that may

provide a method to afford additional

metals feedrate flexibility without the

need of high metals spiking (otherwise

necessary to identify a metals feedrate

for an associated metals emission

level).49 One promising approach would

use a statistical extrapolation

methodology.50

Under this approach a source would

use the metal feedrates and emission

rates associated with a MACT

performance test to extrapolate to higher

allowable feedrates and emission rates.

The Agency believes that the upward

extrapolation procedure developed can

conservatively be used to allow for

higher metals feedrate limits, but still

ensure that the facility is well within

any applicable MACT (or RCRA)

emissions limit.51 Although downward

interpolation (i.e., between the

measured feedrate and emission level

and zero) was also investigated, the

Agency is concerned that downward

interpolation may not be conservative

primarily because system removal

efficiency decreases as metal feedrate

decreases. Thus, projected emissions at

lower feedrates may in fact be lower

than actual emissions. Consequently,

the Agency is not inclined to allow

downward interpolation.

The Agency expects that any

extrapolation methodology would be

reviewed and approved by regulatory

officials. Sources would request

approval to extrapolate feedrates as part

of the performance test plan that would

be submitted at least 60 days prior to the

test date. See § 63.7(b) and (c) and

proposed § 63.1208. The review would

consider in particular whether: (1)

Performance test metal feedrates were

appropriate (e.g., whether feedrates

were at least at normal levels;

depending on the heterogeneity of the

waste, whether some level of spiking

would be appropriate; and whether the

physical form and species of spiked

material is appropriate); and (2) whether

the requested, extrapolated feedrates

were warranted considering historical

metal feedrate data. In addition,

regulatory officials would review the

performance test results in making a

finding of compliance required by

§ 63.6(f)(3) to ensure that emission test

results have been interpreted properly

and that the extrapolation procedure is

appropriate for the source.

The Agency is discussing this

approach with some hesitation because

facilities would be able to: (1) Feed

metals at higher rates without a specific

compliance demonstration of the

associated metals emissions; and (2)

obtain approval to feed metals at higher

levels than normal, even though all

combustion facilities should be trying to

minimize metals feedrates. However,

because the Agency remains concerned

that sources would otherwise continue

to feed metals during compliance testing

at high levels,52 to it may be appropriate

to consider this extrapolation approach

as a means to reduce unnecessary

emissions and costs incurred by

facilities (and the health risk to testing

personnel) during performance tests.

EPA invites comment on this

extrapolation approach, and in

particular, as to whether the approach is

adequately conservative and practicable.

D. Consideration of Site-Specific

Variances for Cement Kilns and LWAKs

The Cement Kiln Recycling Coalition

(CKRC) has provided comments on the

proposed rule suggesting that two

variance procedures be incorporated in

the final rule: (1) Waiver of the Hg,

SVM, LVM, and/or HCl/Cl2 standards

when metals or chlorine in minerals and

related process materials cause the

source to exceed the standard even

though the source is demonstrable using

MACT control; and (2) waiver of the HC

standard for the main stack of a long

kiln that does not monitor CO or HC in

the by-pass duct when organics

desorbed solely from minerals and

related process materials cause the

source to exceed the standard in the

main stack.
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24239

53H.R. Rep. No. 101–952, at p.339, 101st Cong.,

2d Sess. (Oct. 26, 1990).

54CKRC cites additional authority in its letter to

B. Holloway and F. Behan (USEPA) of March 10,

1997 addressing these issues. Available in RCRA

Docket # F–97–CS4A–FFFFF.

55To meet its RCRA mandate, the Agency would

continue to evaluate emissions under the omnibus

permit authority to ensure that controls were

adequate to protect human health and the

environment.

56The Agency has acknowledged that HC in the

main stack of a long kiln can be generated by

desorption of trace organics in raw material

feedstocks as well as from fuel combustion.

57Higher back-end temperatures may be

associated with higher rates of D/F formation.

58Neither approach would appear to be

appropriate for kilns that feed hazardous waste at

locations other than the clinker end. The concern

is that the kiln gas that is withdrawn for testing at

the mid-kiln location for compliance with the CO

or HC limit may not be representative of hazardous

waste combustion gases (i.e., either because the

hazardous waste is being fired downstream or, if the

waste is fired at mid-kiln, the waste combustion

gases may not be thoroughly mixed at the point of

kiln gas withdrawal for CO and HC monitoring).

CKRC notes that the Conference

Report for the Clean Air Amendments of

1990 53 states that:

For categories and subcategories of sources

of hazardous air pollutants engaged in

mining, extraction, beneficiation, and

processing of nonferrous ores, concentrates,

minerals, metals, and related process

materials, the Administrator shall not

consider the substitution of, or other changes

in, metal- or mineral-bearing raw materials

that are used as feedstocks or materials

inputs, * * * in setting emission standards,

work practice standards, operating standards

or other prohibitions or requirements or

limitations under this section for such

categories and subcategories.

It should be noted that this language

is not reflected in the legislative text,

which states without caveat that MACT

standards may be based on ‘‘process

changes, substitution of materials or

other modifications.’’ CAA section

112(d)(2)(A).54 However, assuming that

CKRC’s request for these variances has

merit, and if the variances are

incorporated in the final rule, they

would apply to LWAKs as well given

that LWAK raw materials could also

cause those combustors to exceed the

standards using MACT control. We

solicit comment on whether these

variances are appropriate and workable,

and on the potential issues raised

below.55

1. Variance for metals or chlorine in

minerals and related process materials.

It may be appropriate to waive any

MACT standard for a metal or group of

metals or the standard for HCl/Cl2 if the

source documents that it cannot comply

with the standard while using MACT

control solely because of raw material

feed. As examples, MACT control for Hg

would be hazardous waste feedrate

control at a specified MTEC. MACT

control for SVM and LVM would also be

feedrate control at a specified MTEC

and compliance with the PM standard.

A condition of the variance could be

that the source would be required to

document that the concentration of

metal or chlorine (for which it is seeking

the variance) in hazardous waste and

any non-mineral feedstock is within the

range of normal levels for the industry.

This would ensure that metals and

chlorine emissions attributable to nonmineral feedstreams are equivalent to

those from sources meeting MACT.

We therefore request comment on the

following issues:

• How would normal levels be

determined? What statistics should be

used? What should be the baseline year

for the determination (e.g., a given year

(2000, or the compliance date of the

rule)?

• Should the variance be granted only

if the hazardous waste and/or nonmineral feedstreams have lower than

normal levels of metals or chlorine?

How much lower (e.g., 25th percentile

levels, 40th percentile levels)?

• Would it be necessary to establish

the normal levels in the rule, or should

they be established initially, on a caseby-case basis?

• Should the Agency be concerned if

levels of metals or chlorine in mineral

feedstocks decline over time thus

enabling the source to meet the

standard? If so, what monitoring

approach would be appropriate to

identify when that occurred?

• When should variance petitions be

submitted to the State or EPA regulatory

officials (e.g., 120 or 180 days prior to

the compliance date)?

2. Variance for organics in minerals

and related process materials.

Although current BIF regulations

limit HC levels in kilns to 20 ppmv

irrespective of the source of the

hydrocarbons 56 and the Agency

proposed to maintain that standard

under MACT, CKRC notes that some

sources have to operate inefficiently to

meet the standard. For example, a

source may have to operate back-end

temperatures at higher than normal

levels to oxidize enough of the organics

being desorbed to meet the HC standard.

This means that more fuel than normal

must be fired to provide the extra heat

at the back-end.57

CKRC has suggested approaches

whereby a source can document that

hazardous waste is being burned in

compliance with either the CO limit of

100 ppmv or the HC limit of 10 ppmv.58

In situations where the kiln can monitor

a representative sample of combustion

gas at mid-kiln at least temporarily

during a performance test to document

compliance with the CO limit of 100

ppmv (or a HC limit of 10 ppmv), limits

on key combustion parameters would be

established based on operations during

the performance test. The operating

limits would be continuously monitored

to ensure compliance with the CO or HC

limits. Limits on the following operating

parameters would be established: kiln

gas oxygen at the kiln outlet; kiln gas

residence time using raw material

feedrate as a surrogate; and combustion

zone temperature, using an appropriate

surrogate or measured at an appropriate

location.

CKRC also suggested that sulfur

hexafluoride (SF6) could be used as a

continuously monitored compliance

parameter in lieu of limits on other

parameters, except oxygen. This is

because SF6 is recognized as a

temperature labile compound—it is

more stable than most any other toxic

compound under a temperature-failure

mode of organics destruction. SF6 is

not, however, an indicator of oxygendeficient combustion failure modes—it

is destroyed at high temperatures

irrespective of oxygen levels. Given that

both adequate temperature and oxygen

are necessary for good combustion, an

oxygen limit as well as an SF6 feed limit

and emission limit would be established

under this option based on a

performance test documenting

compliance with either the CO or HC

limits at mid-kiln.

Finally, CKRC suggested variance

approaches for the more problematic

situation where a kiln is not able to

sample kiln gas at mid-kiln for

compliance with the CO or HC limit.

One approach would be to allow a kiln

to document compliance with the CO

limit of 100 ppmv or the HC limit of 10

ppmv in the main stack when burning

hazardous waste but temporarily

feeding imported, low organic raw

material. Under this approach, as with

the approaches discussed above,

operating limits on oxygen levels in kiln

gas at the kiln outlet, residence time of

combustion gas, and combustion zone

temperature would be established based

on a performance test using the low

organic raw material. Also, continuous

monitoring of limits on feedrates and

emission rates (based on performance

testing) of SF6 could be used in lieu of

establishing limits on residence time

and temperature.

E. Emissions Averaging for Cement

Kilns

Several cement kilns have unique

design or operating procedures that

warrant special consideration in
24240 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

59 CKRC Comments, August 19, 1996, pp 112–

113, Docket Number RCSP–0170.

60 The statutory minimum technology

requirement for incinerators (see RCRA 3004(o)(B))

requires the ‘‘attainment’’ of 99.99 percent

destruction and removal efficiency. DRE testing

could be replaced by an alternative that is equally

or more stringent (e.g., compliance with stringent

limits on CO or HC) to ensure attainment of 99.99

percent DRE.

61 The Agency evaluated approximately 455 DRE

test conditions, where CO was less than 100 ppmv

and 273 test conditions where HC was less than 12

ppmv, to determine if compliance with stringent

CO and HC limits would ensure that 99.99% DRE

was being achieved. Ten sources failed DRE even

though CO or HC levels were below 100 ppmv or

12 ppmv (on a run average basis), respectively. Nine

of the failures could be explained by: (1) Selecting

principal organic hazardous constituents (POHCs)

that were also common products of incomplete

combustion; (2) feeding low concentrations of

POHCs (a phenomenon of DRE testing is that it is

very difficult to measure 99.99% DRE when POHCs

are fed at low concentrations, even though emission

concentrations may be trivial); or (3) feeding

aqueous waste with such low concentrations of

organics that, even under poor combustion

conditions, the waste did not generate high levels

of CO or HC. See USEPA, ‘‘Draft Technical Support

Document for HWC MACT Standards (NODA),

Volume II: Evaluation of CO/HC and DRE

Database’’, April 1997.

62 It could be argued that this is due to two

factors: (1) during successful DRE testing many

sources operated at CO or HC levels that were well

below the 100/10 levels; and (2) it is not clear that

those sources would continue to achieve 99.99%

DRE at higher CO or HC levels (but not exceeding

the 100/10 levels). This is unlikely to be a major

concern, however, because combustion devices

operating at CO levels under 100 ppmv are

generally considered to be operating under good

combustion conditions that would ensure 99.99%

DRE in any event.

63Under an option the Agency is considering for

establishing MACT standards for CO and HC, a

source would be able to elect whether to comply

with either the CO or HC standard. Although CO

is not a direct measure of HC emissions, the Agency

is considering requiring sources that elect to

comply with the CO standard to document that

their HC emissions also meet the standard.

64The Agency’s analysis to date has focused on

the 99.99% DRE standard. We have not investigated

whether sources that burn ‘‘dioxin-listed waste’’

under § 264.343(a)(2) and are required to

demonstrate 99.9999% DRE are likely to achieve

that DRE when operating under stringent CO and

HC levels. Given that there are few HWCs that are

permitted to manage such wastes and given the

high toxicity potential of such wastes, the Agency

is inclined to continue to require DRE testing at

facilities handling those wastes.

65 Long cement kilns generally cannot meet the

stringent CO and HC limits applicable for waste

combustion (i.e., 100/10 ppmv) because of organics

in raw materials. Thus, the Agency proposed that

demonstrating compliance with the

MACT standards, as discussed below.

1. Preheater or Preheater/Precalciner

Kilns with Dual Stacks. Some preheater

or preheater/precalciner kilns are

designed with separate main and alkali

by-pass stacks. To demonstrate

compliance with the emission standards

(other than the CO/HC standards where

compliance is based on emissions in

either the main or by-pass stack), it is

appropriate to allow such kilns to

document either that both stacks meet

the applicable emission limits, or that

the stacks meet the limits considering

flow-weighted average emissions. This

is the approach currently used for

compliance for the PM NSPS, and it is

appropriate as well for the MACT

standards that the Agency has proposed.

2. Kilns that operate an in-line raw

mill. Some cement kilns vent the kiln

gas through the mill that grinds the raw

material (i.e., raw mill) to help dry the

raw material before charging to the kiln.

Such designs are referred to as ‘‘in-line

raw mills’’. When the raw mill is out of

service for maintenance, approximately

10% of the time annually, kiln gas bypasses the mill and is vented to the

stack after passing through the PM

control device. (Stored milled raw

material is charged during these periods

of mill downtime.) The Cement Kiln

Recycling Coalition indicates that

emissions of HAPs that the Agency

proposed to regulate can be different

when gas is vented through the raw mill

versus periods of time when the mill is

out of service.59

It appears appropriate to base

compliance with the MACT emission

standards for such kilns on a timeweighted average basis. Sources would

use historical information on utilization

time for the in-line raw mill to

document the time-weighted average

and would present this information to

regulatory officials as part of the test

plan. Further, sources would be

required to conduct performance testing

under both operating conditions: with

the raw mill on-line and off-line.

III. DRE Testing Considerations

In the NPRM, the Agency proposed

that the 99.99 percent destruction and

removal efficiency (DRE) standard be

retained under RCRA authority. See 61

FR at 17447. Although EPA could have

proposed the DRE requirement as part of

the MACT standards to help control

organic HAPs, the Agency explained

that doing so would have raised

significant practical implementation

concerns. This is because MACT

standards are generally selfimplemented by facilities to a large

degree whereas DRE testing has

historically involved a detailed and

iterative process between a facility and

the regulatory agency.

The Agency received comments that

raised other concerns, including: (1)

Whether it is necessary for a source to

actually perform a DRE test to ensure

that it is achieving DRE; 60 and (2) how

can the Agency ensure that RCRA DRE

testing is coordinated with MACT

performance testing.

The Agency has reconsidered DRE

testing issues and is today requesting

comment on options for ensuring

compliance with a DRE standard, and

how to coordinate DRE testing with

MACT performance testing.

A. Options for Ensuring Compliance

with a DRE Standard

The Agency has investigated whether

compliance with the CO or HC MACT

standards would ensure that a source is

achieving 99.99% DRE 61. The vast

preponderance of the data indicate that

when a source is achieving CO levels

under 100 ppmv or HC levels under 10

ppmv, it is virtually always also

achieving 99.99% DRE.62 The Agency’s

investigation noted, however, an

atypical, failure mode for the CO/HC

versus DRE relationship: when low

organic content waste is fed into a

region of a combustor other than the

flame zone (e.g., into an unfired

afterburner). One test condition of the

approximately 455 investigated failed

the CO/HC versus DRE relationship for

this reason. This was a highly unusual

test condition, and does not represent

good combustion practice. CO levels

were likely low because flame

combustion was not occurring, and HC

was likely low because the waste could

have had only trace levels of toxic

organics that did not contribute

significantly to the HC loading (but

which could nonetheless pose a health

or environmental hazard).

Given the general relationship

between CO, HC, and DRE and the

highly unusual nature of the lone

exception, the Agency is considering

whether DRE testing is warranted in all

cases for sources complying with the

MACT CO and HC standards. The DRE

test is a complicated, expensive test. In

addition, although it can help indirectly

to ensure that a source is operating

under good combustion conditions, it

may not provide the operationally direct

level of assurance of good combustion

conditions that CO or HC does. The data

show that sources can be achieving

99.99% DRE even though CO or HC

levels exceed values considered to

represent good combustion (i.e., CO of

100 ppmv, HRA, and HC of 10 ppmv,

HRA).63

Accordingly, the Agency is

considering three options for reducing

the DRE testing burden, as discussed

below.64 Under all options where DRE

testing would be waived, a source

would have to be in compliance with

the final MACT standards for CO/HC,

which will be sufficient to show ensure

compliance with the DRE standard as

well.65
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24241

such kilns comply with a CO level of 100 ppmv or

a HC level of 20 ppmv. Notwithstanding the

inability to document good combustion conditions

by complying with stringent CO/HC limits, the

Agency believes that cement kilns that fire

hazardous waste into the clinker end of the kiln

will virtually always achieve 99.99% DRE because,

to make marketable products, clinker temperatures

must be approximately 2700° F, and combustion gas

temperatures are typically several hundred degrees

hotter than the solids temperature. These

temperatures are theoretically high enough to

ensure destruction of organic compounds in the

waste. Consequently, such kilns should not be

precluded from the waivers discussed in the text.

If such a kiln were to inject hazardous waste at

nonflame zone locations such as mid-kiln or at the

raw material end of the kiln, however, we are

concerned that DRE may not always be achieved.

The kiln would not be eligible for the DRE waiver.

66 The Agency also considered requiring sources

to submit draft test protocols one year prior to the

test date, regardless if the comprehensive

performance test is to be combined with a DRE

demonstration. We determined that may not be

appropriate, however, because normal

comprehensive performance tests should not

require a review process longer than provided by

the CAA-MACT general requirement. Therefore, the

one-year test review period would only apply for

those sources that wish to coordinate the

comprehensive performance (or confirmatory) test

with a DRE test.

B. DRE As a MACT Versus RCRA

Standard

In investigating approaches to ensure

coordination of DRE testing with MACT

performance testing, the Agency has

reconsidered whether the DRE standard

could be effectively implemented as a

MACT standard (to help control organic

HAPs). To ensure coordination of DRE

and MACT performance testing, the

Agency is considering extending the test

plan review period from the proposed

60 day period (see proposed

§ 63.1208(e) and § 63.7(b)(1)) to one year

to allow regulatory officials time to

consider DRE testing in context with

MACT testing. With this opportunity for

coordinating the testing, the Agency’s

concerns expressed at proposal about

the difficulty of implementing the DRE

standard under the self-implementing

regime of MACT may be largely

overcome (i.e., if the Agency

incorporates into the MACT standards

opportunity to review and approve the

DRE test protocol). Thus, the Agency is

considering incorporating the DRE

standard as a MACT standard.

Sources wishing to perform a

combined DRE and comprehensive

performance test would have to submit

the test plan one year in advance of the

test. If the review requires more than

one year, the Agency can extend the

testing date for coordination purposes

(assuming the source has made a good

faith effort to cooperate with regulatory

officials to identify an appropriate test

protocol). However, there would be no

extensions granted for the initial

comprehensive performance test

because it is imperative that sources

document compliance with the MACT

emission standards (including those for

the high priority HAPs, D/F, Hg) on

schedule. Sources wishing to perform a

combined initial comprehensive

performance and DRE test would

therefore have to be diligent in working

with regulatory officials to ensure that

the combined test protocol is developed

and approved in a timely manner.66

The Agency invites comment on these

issues, including whether DRE should

be incorporated as a MACT standard,

and irrespective of that decision,

whether a one-year review period

provides adequate opportunity to

review a combined DRE test and

comprehensive performance test

protocol.

IV. Notification and Reporting

Requirement Considerations

A. Public and Regulatory Notification of

Intent to Comply

In the proposed rule, the Agency

requested comment on strategies to

encourage or require affected sources to

comply with the final emissions

standards at the earliest possible date.

The Agency also asked for views on

methods that could be used to

determine when a source could

realistically conclude whether it will

comply in a timely fashion with the

final standards (61 FR at 17416). A

number of commenters argued for the

Agency to require a submission from

affected sources that identifies whether

and how the facility intends to comply

with the final standards. This

notification requirement was referred to

as a ‘‘Notification of Intent to Comply.’’

The purpose of the submission would

be to identify the sources that will not

comply with the final standards so that

those sources could be forced to

terminate waste burning activities as

soon as possible following the effective

date of the final HWC rule.

Other commenters, responding to our

request for comment regarding the

proposed permit modification options

(61 FR at 17455), suggested that all

facilities be required to submit a plan

that outlines the procedures each

facility intends to follow to comply with

the final standards. However, the

purpose of this submission would be to

begin an early process of

communication between the public and

the facility through the public

disclosure of the facility’s compliance

strategy.

The Agency has reviewed these

comments and supports the goals and

purposes of a requirement that compels

sources to identify their intentions to

comply with the final rule, and to

describe how they will achieve that

compliance. Furthermore, the Agency

supports any process that promotes

public notification and interaction with

respect to a hazardous waste

combustor’s future operations. To the

extent that some limitations on public

participation would be the result of a

streamlined permit modification process

that may be finalized ahead of the HWC

MACT rule, promotion of early public

notification and intervention in this part

of the rule is appropriate and desirable

given our general policies in that regard

(see, e.g., RCRA Expanded Public

Participation Rule, 60 FR 63417 (Dec.

12, 1995)). Therefore, the Agency is

considering a notification requirement,

based on and growing out of ideas that

were presented in comments, that may

be applied to sources affected by the

final rule. This notification requirement,

called the Public and Regulatory

Notification of Intent to Comply

(PRNIC), would involve the facility

submission and public disclosure of a

plan that relates to whether and how the

facility intends to come into compliance

with the final standards.

However, due to enforcement and

implementation issues, the Agency is

concerned that it is not feasible to use

a submission that identifies only a

facility’s future ‘‘intentions’’ as the legal

basis to force a facility to terminate

waste burning activities before the

statutorily based compliance period of

three years. Moreover, any official

review and approval of such

submissions could conceivably slow

down the rate at which facilities come

into compliance with the final

standards. This would thwart the

objectives of a streamlined permit and

compliance process.

The Agency believes that the most

effective application of such a

submission is to promote public

awareness, as well as discussion

between a facility and its community,

which will afford them an opportunity

to engage in discussions regarding the

details of the facility’s plans to comply

with the final standards. However, the

Agency does not intend for this

submission to undergo a formal review

by the regulatory agencies involved.

The Agency requests comment on this

option which requires sources to

prepare and submit for public comment

a notification identifying the source’s

intentions to comply with the final rule

as well as the strategy they intend to

follow to assure compliance by the

compliance date. This notification

requirement would apply to all sources
24242 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

67Memorandum, from Craig Campbell (CKRC) to

Matthew Hale Jr. (EPA), regarding compliance plans

under the HWC MACT Rule, dated March 18, 1997.

burning waste on the effective date of

the final HWC rule, and would require

sources to prepare a draft notification,

announce the availability of the draft

notification as well as a future informal

public meeting to discuss the draft

notification, hold an informal public

meeting, submit the final notification to

all appropriate regulatory agencies, and

update the notification as necessary.

The Agency intends for the

information contained in the draft

notification to provide enough detail so

that the public can engage in a

meaningful review of the facility’s

compliance strategy. For example, if in

the draft notification a facility identifies

and describes the type(s) of control

technique(s) being considered, the

facility should include, as appropriate,

waste minimization and/or pollution

control options that may have been

evaluated.

EPA also requests comment on a

requirement for affected sources to hold

at least one informal meeting with the

public before submitting the final

notification to the appropriate

regulatory agencies. The goal of this

informal meeting is to provide a forum

to facilitate dialogue between the

affected source and its community. The

meeting should provide an open,

flexible and informal occasion for the

facility and the public to discuss various

aspects of the facility’s compliance

strategy because it provides the public

direct input to the facility owners/

operators. In addition, the meeting

affords facility owner/operators the

opportunity to gain an understanding of

the public’s expectations, which can

then be addressed and included in the

facility’s final submission. The Agency

anticipates that the facility and the

public will share ideas, educate each

other, and continue to establish a

framework for sound communication.

However, as suggested in comments

received from CKRC,67 the Agency

understands that the early timing of the

meeting may affect a facility’s ability to

have complete or fully accurate

information, but the Agency believes

that the benefits of early public

involvement and access to information

outweigh the drawbacks of incomplete

information. Furthermore, the time

period between the effective date of the

HWC rule and the informal meeting

announcement should provide a facility

sufficient time to collect, analyze, select,

and plan a compliance strategy.

However, comments are invited on

other appropriate time periods between

the public notification and the informal

public meeting, and on the time period

necessary to collect the information

required for the PRNIC.

Another timing issue relates to when

a facility should notify the community

regarding the availability of the draft

PRNIC. At this stage, the Agency is

considering to require that the

notification be made on or before 210

days following the effective date of the

final HWC rule. This would necessitate

that an announcement of the informal

public meeting and the availability of

the draft PRNIC be made 30 days prior

to the meeting in a manner that is likely

to reach all affected members of the

community. The Agency is considering

that this announcement, of the informal

public meeting and draft PRNIC

availability, should be required in three

ways: As a display advertisement in a

newspaper of general circulation; as a

clearly marked sign on the facility

property; and as a radio broadcast. Each

of these notices would have to include

the date, time and location of the

meeting, a brief description of the

purpose, a brief description of the

facility, a statement asking people who

need special access to notify the facility

in advance, and a statement describing

how the draft PRNIC can be obtained.

The Agency requests comment on this

approach that requires facilities to hold

an informal public meeting prior to the

submission of the final PRNIC to the

regulatory authorities.

An additional requirement of the

notification approach being considered

involves the submission, to the

appropriate regulatory agencies, of the

final PRNIC 270 days following the

effective date of the final HWC rule. The

submission would contain the following

information: The name and location of

the owner operator; the location of the

source; a statement as to whether the

source is a major or area source; a

description of any waste minimization

and pollution control technique(s)

considered; a description of the

emission monitoring technique(s)

considered; a description of the waste

minimization and pollution control

technique(s) effectiveness; a description

of the evaluation process used to select

the waste minimization and/or

pollution control technique(s); and an

outline of the key dates in the process

that the facility plans to follow to

implement the selected waste

minimization and/or pollution control

technique(s). This submittal should also

capture the major comments or ideas

that were discussed in the public

meeting or that were submitted in

response to the release of the draft

PRNIC.

The final requirement of the

notification approach being considered

involves updates to the final PRNIC

following a significant change in the

facility’s implementation strategy. A

significant change would be analogous

to a change that would trigger a RCRA

class two or class three permit

modification request, and would apply

only to changes that depart from the

strategy described in the final PRNIC.

Examples of some changes that may be

considered significant changes are as

follows: A change in the pollution

control technique to be implemented; a

request for permit modification; a

request for an extension of the

compliance date; or a decision to stop

or to continue burning waste that is

contrary to the final PRNIC.

Additionally, all sources could be

required to notify the public via a

mailing to the facility’s mailing list

within 30 days following a

determination that a significant change

has occurred in the facility’s

implementation strategy. The change

would have to be described in writing

and made available to requesting parties

via placement in an information

repository or through direct transmittal.

This requirement would be in keeping

with the spirit of the PRNIC, which is

to keep the public informed of any

significant changes in the facility’s

compliance and implementation plan.

The Agency invites comment on this

submittal and the submittal process, and

requests information on the benefits and

burden associated with such a process.

The Agency specifically invites

comment on the use of permit

modification criteria to identify a

significant change that would

necessitate an update to the PRNIC.

B. Data Compression Allowances

The Agency is considering allowing

the use of data compression techniques

in the recording of continuously

monitored parameters under this rule.

This is in response to comments on the

proposed rule regarding the additional

burden associated with the proposed

monitoring and recording requirements

and specific requests to allow data

compression. We are also considering

revisions to parts 264, 265 and 266 that

would be conforming revisions to

ensure that the RCRA rules are

consistent with similar provisions of the

proposed part 63 rules.

Commenters raised the issue of an

additional burden by the proposed

monitoring and recording requirements.

We do not agree that the proposed

requirements pose significant additional

record keeping burdens from current

regulations (i.e., BIF rule) or existing
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24243

permit requirements under RCRA.

However, we are interested in reducing

the information burden—for example,

how much is recorded if the data is

automatically evaluated under an

established set of specifications, while

maintaining the integrity of the data for

compliance evaluation purposes.

Briefly, data compression is the

process by which a facility

automatically evaluates whether a

specific data point needs to be recorded.

Data compression does not represent a

change in the continuous monitoring

requirement proposed in rule. Oneminute averages will continue to be

generated. However, with data

compression, each one-minute average

will be automatically compared with a

set of specifications to decide the need

for recording. New data is recorded

when the one-minute average value falls

outside the set of specifications.

This option should provide a good

opportunity to the regulating agencies to

focus their review of operating data,

because facilities using data

compression will record data that is

indicative of non-steady state operations

more frequently than steady state

operations. This will significantly

reduce, up to 90%, the data subject to

review by the regulating agency as the

facilities’ self-evaluate, under a

previously approved set of

specifications, the data being recorded.

The dynamics of monitored

parameters are not uniform across the

regulated universe, and establishing

national specifications for data

compression techniques in this rule may

not be feasible. Different data

compression techniques can be

successfully implemented for a

monitored parameter to obtain

compressed data that reflect the

performance on a facility specific basis.

As a result the Agency is considering

allowing the sources to request the

regulatory agency to use data

compression techniques that reflect sitespecific conditions of the monitored

parameters and establish data

compression specifications accordingly.

Upon approval, sources may start data

compression techniques based on the

approved set of specification.

At a minimum, a source

implementing data compression will be

required to record a value once every

ten minutes. In combination with the

appropriate set of specifications, a

recorded value every ten minutes will

result in a potential data recording

reduction up to 90%.

As a guideline, for the regulating

agencies and sources EPA has

developed a table to use as a guideline

developing site-specific specification for

data compression techniques. These are

the basis for the specification in the

table:

1. Data compression limit. The closest

level to a permit limit/standard at which

reduced recording is allowed. Within

this level, minute-by-minute data

recording is required. The data

compression limit should reflect a level

at which the specific parameter is

unlikely to exceed its permit limit

within a one-minute change. The other

consideration is to set a data

compression limit at which owners and

operators can practically implement

data compression.

2. Fluctuation limits. The permissible

deviation of new data value from

previously generated value. This

parameter is a reflection of tolerance of

the agency to allow a parameter to

change without requiring the data point

to be recorded. The considerations to

establish the fluctuation limits are (1)

The potential of the regulated parameter

to change in one minute and cause an

exceedance of the permit limit on a

rolling average basis and; (2) the

maximum variation tolerated from a

change of other related operating

parameters (i.e., fuel and temperature,

gas flow and APCD parameters).

We invite comment on allowing data

compression under this rule, including

revising parts 264, 265 and 266, and on

the following table:

FLUCTUATION AND DATA COMPRESSION LIMITS EXPRESSED AS PERCENTAGES OF THE PERMIT/STANDARD LIMITS

Device Parameter Fluctuation

limit ±

Data compression

limit

CEMS ........................................................ Particulate matter ....................................................................... 10% .............. 60%.

CEMS ........................................................ Carbon monoxide 1 hour ........................................................... 10 ppm ......... 50 ppm.

CEMS ........................................................ Total hydrocarbon ...................................................................... 2 ppm ........... 60%.

CEMS ........................................................ Total mercury 10 hour ................................................................ 10% .............. 60%.

CEMS ........................................................ Multi-metal 10 hour .................................................................... 10% .............. 60%.

HCl .............................................................................................. 10% .............. 60%.

Chlorine ...................................................................................... 10% .............. 60%.

Max inlet temperature to dry PM APCD .................................... 10° F ............ Limit ¥30° F.

Activated carbon injection ......................... Min carbon injection feedrate (carbon feed through injector) .... 5% ................ Limit +20%.

Min carrier fluid flowrate or nozzle pressure drop ..................... 20% .............. Limit +25%.

Dioxin inhibitor ........................................... Min inhibitor feedrate .................................................................. 10% .............. 60%.

Catalytic oxidizer ....................................... Min flue gas temperature at entrance ........................................ 20° F ............ Limit +40° F.

Max flue gas temperature at entrance ....................................... 20° F ............ Limit ¥40° F.

Maximum waste feedrate ........................................................... 10% .............. 60%.

Min combustion chamber temperature (exit of each chamber) 20° F ............ Limit +50° F.

Good combustion and APCD efficiency ... Maximum flue gas flowrate or production rate .......................... 10% .............. 60%.

Feed control .............................................. Maximum total metals feedrate (all streams) .............................

Maximum pumpable liquid metals feedrate ...............................

10% .............. 60%.

Maximum total ash feedrate (all streams) ................................. 10% .............. 60%.

Maximum total chlorine feedrate (all streams) ........................... 10% .............. 60%.

Wet scrubber ............................................. Minimum pressure drop across scrubber .................................. 0.5′′ water .... Limit +2′′.

Min liquid feed press .................................................................. 20% .............. Limit +25%.

Minimum liquid pH ...................................................................... 0.5 pH unit ... Limit + 1 pH unit.

Min blowdown (liquid flowrate) or max solid content in liquid ... 5% ................ Limit +20%.

Minimum liquid flow to gas flow ratio ......................................... 10% .............. Limit +30%.

Ionizing wet scrubber ................................ Minimum pressure drop across scrubber .................................. 0.5′′ water .... Limit +2′′ water.

Minimum liquid feed pressure .................................................... 20% .............. Limit +25%.

Min blowdown (liquid flowrate) or max solid content in liquid ... 5% ................ Limit +20%.

Minimum liquid flow to gas flow ratio ......................................... 10% .............. Limit +30%.

Min power input (kVA: current and voltage) .............................. 5% ................ Limit +20%.

Dry scrubber .............................................. Min sorbent feedrate .................................................................. 10% .............. Limit +30%.
24244 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

FLUCTUATION AND DATA COMPRESSION LIMITS EXPRESSED AS PERCENTAGES OF THE PERMIT/STANDARD LIMITS—

Continued

Device Parameter Fluctuation

limit ±

Data compression

limit

Minimum carrier fluid flowrate or nozzle pressure drop ............ 10% .............. Limit +30%.

Fabric filter ................................................ Minimum pressure drop across device ...................................... 1′′ water ....... Limit +2′′ water.

ESP ........................................................... Min power input (kVA: current and voltage) .............................. 5% ................ Limit +20%.

V. Waste Minimization and Pollution

Prevention

A. Overview

Amendments to RCRA in 1984, and

the Pollution Prevention Act of 1990

establish a clear national policy

preference for pollution prevention and

environmentally sound recycling as the

nation’s top priority environmental

management methods, over treatment,

storage and disposal. Pollution

prevention, also referred to as source

reduction, includes any practice that

reduces the amount of pollutants

entering a waste stream, prior to

recycling, treatment or disposal. Waste

minimization, a term particular to RCRA

and EPA’s hazardous waste program,

includes pollution prevention (or source

reduction) and environmentally sound

recycling. Combustion for treatment or

destruction is a form of treatment, and

is not included in the definitions of

pollution prevention, source reduction,

waste minimization and/or

environmentally sound recycling.

Based on previous studies, stringent

limits on pollution control devices

generally provide a strong incentive for

companies to pursue less costly waste

minimization measures to achieve

compliance. The implementation of the

Land Disposal Restrictions program has

shown this to be the case in the RCRA

program. Waste minimization measures

can, in many cases, provide companies

with a variety of benefits, including:

improvements in production yields,

reduced worker exposure, reduced

waste volumes, reduced waste

management costs, reduced liability,

and reduced compliance burdens. As a

result, many companies, including those

affected by today’s rulemaking, have

made significant progress identifying

and installing waste minimization

measures that result in one or more of

these benefits. In addition, hazardous

waste generators that transport waste

off-site for treatment, storage or disposal

are required to certify on each

hazardous waste manifest that they have

a waste minimization program in place.

In addition, facilities that have a RCRA

permit to treat, store or dispose of

hazardous wastes are required to certify

annually that they have a waste

minimization program in place (See

sections 3002(b) and 3005(h) of RCRA).

Past studies indicate that existing

regulations can also contain inherent

barriers that prevent companies from

identifying and installing additional

waste minimization measures that could

be cost effective and provide an

alternative or supplemental means to

achieve compliance. Potential

regulatory impediments can include:

Tight compliance deadlines that

preclude taking extra time to explore

waste minimization alternatives,

perceptions that end-of-pipe technology

is preferred by government agencies

over less well known waste

minimization measures to achieve

compliance, a tendency to continue

relying on pollution control technology

once a company has sunk available

capital into end-of-pipe controls, and a

lack of government willingness to

explore more flexible compliance

approaches.

During extensive interaction with

public stakeholders during the

development of EPA’s Hazardous Waste

Minimization National Plan (released in

1994), some companies emphasized that

short compliance deadlines after the

promulgation of end-of-pipe standards

are a significant impediment to fully

identifying and installing waste

minimization measures that could either

replace or supplement end-of-pipe

pollution control measures that may

still be necessary. As a result,

companies are likely to opt for installing

‘‘end-of-pipe’’ pollution controls to meet

compliance deadlines, instead of

pursuing waste minimization and

pollution control measures as a

compliance approach. At large complex

manufacturing facilities (such as

chemical manufacturing plants), short

compliance deadlines are a particular

barrier since completing a waste

minimization options assessment

requires consideration of chemical

reaction redesign, testing and

installation. In contrast end-of-pipe

controls can often be installed more

quickly than waste minimization

process changes, even though they may

be more expensive. In addition, once

capital has been sunk into end-of-pipe

pollution controls, there is little

incentive for companies to then spend

money exploring pollution prevention/

waste minimization options that would

offset the need for the end-of-pipe

controls. This factor is one of the major

factors to consider in today’s

rulemaking. This is discussed in more

detail below.

B. EPA Proposed Flexible Waste

Minimization Incentives

EPA was aware, in its April 1996

proposal for this rulemaking, that

promulgating MACT standards may

contain some inherent barriers to

identifying and installing waste

minimization technologies that could be

more cost effective for meeting

environmental protection standards (in

some cases) than end-of-pipe air

pollution control equipment alone.

Consequently, EPA requested comment

on three regulatory incentives that could

partially offset potential barriers and

provide regulated companies with an

increased opportunity to identify and

install waste minimization technologies

that reduce or eliminate hazardous

waste entering combustion feed streams

as a cost effective approach to

compliance. EPA’s objective in this

effort is to promote flexibility in the use

of waste minimization measures that

would reduce the amount and/or

toxicity of hazardous wastes entering

combustion feed streams, either as an

alternative to end-of-pipe combustion

measures, or in combination with

combustion measures, to meet MACT

standards.

EPA requested comment on two

approaches that use waste minimization

facility planning to identify cost

effective waste minimization measures

that reduce hazardous wastes entering

combustion feed streams. Waste

minimization planning has been used in

over 20 states as a method to encourage

companies, particularly those that

generate and manage wastes on site, to

identify cost effective waste

minimization measures that can be used

in place of, or in combination with, endof-pipe pollution control measures. Of

the 21 commercial incinerators and the

141 on-site hazardous waste

incinerators facilities known to be

covered by today’s rule, 43–44 percent
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24245

of the facilities are in states that have

mandatory waste minimization

planning programs; 14 percent are in

states that have voluntary waste

minimization planning programs; and

42–43 percent are in states that do not

have formal waste minimization

planning programs.

The first waste minimization facility

planning approach proposed for

comment sought to encourage facilities

to reduce the amount of hazardous

waste entering combustion feed streams

as much as possible through cost

effective waste minimization measures.

The proposal sought to accomplish this

objective by requiring all facilities

covered by this rulemaking to provide to

the appropriate EPA or State permitting

authority adequate information on waste

minimization measures that would

reduce hazardous wastes entering

combustion feed streams. Requiring

facilities to formally consider cost

effective waste minimization options

would raise the likelihood that

hazardous waste generation could most

cost effectively be reduced at the source

or recycled, as a preferred approach to

combustion. Since many of these

facilities are located in states that have

mandatory or voluntary waste

minimization planning programs, EPA

hoped to build on a process already in

place. States that have mandatory waste

minimization planning programs

generally require facilities to provide a

description of changes in process

equipment, raw materials, materials

handling, recycling, maintenance or

other changes that would reduce the

amount and/or toxicity of wastes that

are treated or disposed. None of the

existing mandatory or voluntary State

waste minimization planning programs

specifically address reductions of

combusted hazardous as an objective of

the planning process. EPA requested

comments on this approach to

determine if the approach could provide

greater flexibility for facilities to build

on requirements of existing state

programs to achieve compliance with

MACT standards.

In the second waste minimization

planning option, EPA proposed to

provide EPA Regions and States with

the discretionary authority to make case

by case determinations regarding which

facilities would be required to provide

information on waste minimization

alternatives to reduce hazardous wastes

entering combustion feed streams. This

determination could take into account

several factors, including, for example,

whether an existing state program had

already accomplished the equivalent of

this objective, the extent to which this

requirement may be too burdensome for

some states, and the extent to which

facility specific conditions indicate

emissions could be best controlled by

feed stream management and waste

minimization at the source.

The third waste minimization

incentive EPA proposed for comment

allows facilities to apply for up to a one

year extension to the three year

compliance period allowed under the

CAA and 40 CFR 63.6(i)(4)(i)(A) in cases

where facilities need additional time to

identify and install waste minimization

measures that would reduce hazardous

wastes entering combustion feed

streams as a method (either alone or in

combination with combustion or other

treatment technology) to achieve

compliance. 40 CFR 63.6(i)(6)(i)

describes the requirements for

requesting a compliance extension. A

request must include a description of

the pollution control, process changes

or process equipment to be installed, a

compliance schedule that describes the

dates by which these controls, process

changes and process equipment will be

initiated, the dates by which installation

will be completed, and the date by

which compliance will be achieved. The

Administrator or a State that has an

approved Part 70 permit program or has

been delegated the authority to

implement and enforce the emission

standard for that source may grant such

extensions. This incentive would, at

least in part, offset some of the time

barriers large companies might need to

fully explore and install waste

minimization options in addition to any

combustion equipment that may still be

necessary.

C. Comments Received

EPA received comments on waste

minimization from 22 commenters.

Companies that operate on-site units

(many of which are large chemical

plants) commented that, while waste

minimization can provide a cost

effective approach to compliance,

neither the three year compliance

period allowed for this rule, nor the

three years plus a one year extension is

sufficient time to complete the two track

task of designing, testing and installing

waste minimization process changes

that reduce hazardous wastes entering

combustion feed streams, and designing

and installing any combustion or other

treatment equipment that may

nevertheless be necessary. Waste

minimization is an on-going process

that should be continually under

investigation in all companies.

However, EPA agrees that in cases

where standards are promulgated that

change the economics of how much

pollution can be emitted to the

environment, even on-going waste

minimization programs may not be able

to anticipate the best combination of

waste minimization and treatment

measures to achieve compliance. EPA

agrees that in some cases, particularly at

large complex manufacturing

operations, the three year compliance

period may not be sufficient time to

consider waste minimization measures,

and in other cases, three years plus a

one year extension may not provide

sufficient time.

Commercial facilities continue to

assert that they have few direct

opportunities to pursue waste

minimization since they have little

control over the wastes generated by

their customers. Some commercial

companies believe EPA should

implement ‘‘good actor’’ incentives for

companies that educate their customers

regarding available waste minimization

resources. Such incentives could

include reduced inspection frequencies,

reduced performance testing, and a

recognition program. EPA agrees that

commercial combustors of hazardous

waste have little direct control over the

wastes generated by their customers and

therefore will experience little if any

flexibility from any the waste

minimization incentives proposed for

comment. The comment to implement

good actor incentives as an incentive for

commercial companies to educate their

customers on waste minimization did

not contain sufficient information to

determine the merits of such an

approach. EPA does point out, however,

that this type of concept, i.e., one in

which private industry proposes an

improvement in environmental

performance through and innovative

regulatory approach, is the type of

approach that might be appropriate for

further exploration at a later time.

Three states commented. Two states

believe EPA should encourage waste

minimization in this rulemaking.

However, they believe three years plus

a one year extension may not be enough

time for companies to identify and

install waste minimization measures.

The third state said that waste

minimization incentives should not be

necessary in this rule because

companies have had many years to

pursue waste minimization programs

and should have already considered

waste minimization as an approach to

compliance. EPA agrees with the two

states that, in some cases, three years

plus a one year extension may not be

sufficient time to identify and install

waste minimization measures that

achieve compliance. EPA agrees with

the third state to a limited extent, in that

companies have had many years to
24246 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

implement waste minimization

programs, and notes that most, if not all,

of the companies affected by today’s

rulemaking probably have waste

minimization programs in place.

However, as noted earlier, waste

minimization is an on-going process,

and the stringent requirements of the

MACT standards for hazardous waste

burning facilities may shift the

economics for particular companies in a

way that makes certain waste

minimization measures more cost

effective than they otherwise would

have been, and companies may need

additional time to design and install

these approaches.

EPA’s Interim Final Guidance to

Hazardous Waste Generators on the

Elements of a Waste Minimization

Program in Place (May 28,1993)

recognizes companies make these

determinations on a case by case basis.

EPA’s guidance describes six general

program elements that contribute to

successful corporate waste

minimization programs. These elements

include: (1) Top management support

that emphasizes waste minimization in

its corporate policy, employee

involvement and rewards for ideas that

reduce waste generation, setting goals

for waste reduction, and other proactive

management steps; (2) characterization

of waste generation and waste

management costs, identification of

sources of waste in the production

process, how they were generated, the

value of raw materials and lost products

that are escaping as waste, and the cost

of replacing and managing wasted

materials; (3) periodic waste

minimization assessments that are tied

into other efforts to improve

environmental management; (4) a cost

allocation system that assigns the true

cost of generating and managing wastes

to the activities that generate the waste

in the first place; (5) encourage

technology transfer that shares ideas

and technology between parts of the

organization and with other

organizations where appropriate; and (6)

program implementation and evaluation

that evaluates successes and failures,

and shares information with the public.

While these principles were published

in regard to RCRA’s waste minimization

certification requirement, the principles

can be used as relevant guiding

principles by companies who wish to

consider using waste minimization

measures as a method to reduce

hazardous wastes entering combustion

feed streams regulated under MACT

standards and the Clean Air Act.

One company argues in its comments

that mandatory waste minimization

planning should be made a MACT

requirement so that facilities are forced

to consider source reduction and

recycling alternatives, rather than

simply installing end-of-the-pipe

equipment to control HAP emissions.

The company argues that this approach

would be particularly useful in

controlling combustion feed streams to

limit the combustion of metals and

other constituents that can not be

adequately controlled using end-of-pipe

measures.

EPA has examined this issue closely.

While mandatory facility planning on

the surface may appear to force facilities

to consider waste minimization

solutions, providing appropriate

regulatory incentives and harnessing the

power of public dialogue for companies

to identify and install waste

minimization measures will result in

more waste minimization measures.

Sixteen states have implemented

mandatory waste minimization

planning programs and several more

have implemented voluntary waste

minimization planning programs in an

effort to encourage facilities to pursue

waste minimization measures over endof-pipe measures. A Federal mandatory

and prescriptively detailed waste

minimization planning requirement

would be, at best, marginally effective in

causing large companies (which make

up the population of facilities affected

by today’s regulation) to identify and

install waste minimization measures

beyond what they would do under

current requirements. Large companies

generally already have the necessary

staff, information, and resources to

pursue waste minimization alternatives

where it makes sense to do so. Whether

large companies choose waste

minimization solutions over end-of-pipe

solutions depends on a variety of

economic and other factors that

outweigh attempts to identify additional

waste minimization alternatives. EPA

hopes to encourage minimizing

impediments to waste minimization by

soliciting comments on the approaches

contained in today’s NODA.

Furthermore, the remaining States have

chosen to not implement mandatory or

voluntary waste minimization planning

programs. Some States believe that

mandatory waste minimization

planning does not improve waste

minimization results. It would not be

appropriate for EPA to either add

additional burden to State waste

minimization programs that already

exist or to States that have chosen not

to have waste minimization planning

programs.

EPA is, instead, asking for comment

on a refined approach that encourages

facilities to consider waste

minimization alternatives, uses public

dialogue to advance waste minimization

efforts, and provides regulatory

incentives for companies to pursue

waste minimization solutions. This

approach will achieve many of the same

ends more efficiently than a detailed

and prescriptive mandatory waste

minimization planning requirement.

D. Comments Requested on Additional

Waste Minimization Incentives

EPA is requesting comment on a three

regulatory incentives that are intended

to encourage companies to pursue waste

minimization measures to reduce or

eliminate hazardous wastes entering

combustion feed streams.

The first incentive was proposed in

EPA’s April 19, 1996 MACT proposal,

and is being refined in today’s NODA.

EPA requested comments on granting

regulated facilities the opportunity to

request a one year extension to the three

compliance period allowed under the

Clean Air Act in cases where the

additional time is clearly needed to

identify and install waste minimization

measures that would reduce the amount

of hazardous waste combusted as a

means of achieving compliance. In

today’s NODA, EPA is requesting

comment on several clarifying factors

that will promote consistency while still

allowing flexibility in decision-making

among the EPA Regions and authorized

States who will make determinations on

whether or not to grant one year

extensions to facilities who apply.

EPA is also requesting comment on

extending the agency’s current audit

and penalty policies to allow some

companies to enter into a written

consent agreement or consent orders

(CA/COs) in cases where it is clear that

longer than four years (i.e., longer than

a one year extension) is needed to

identify and install waste minimization

measures that significantly reduce

hazardous wastes entering combustion

feed streams. These two approaches are

discussed more below.

40 CFR 63.6(i) describes the authority,

procedures and requirements for

requesting a one year compliance

extension for meeting MACT standards.

Requests must include certain

information, including: A description of

the pollution control, process changes

or process equipment to be installed, a

compliance schedule that describes the

dates by which these controls, process

changes and process equipment, will be

initiated, the dates by which installation

will be completed, and the date by

which compliance will be achieved.

Today, EPA is requesting comment on

language that clarifies the term ‘‘process

changes’’ in 40 CFR 63.6(i)(6)(i)(B)
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24247

solely with respect to hazardous waste

burning incinerators, LWAKs and

cement kilns, to make it clear that waste

minimization measures are included in

the meaning of process changes for

meeting MACT standards.

By making this clarification, EPA

hopes to encourage the use of waste

minimization measures to reduce the

amount of hazardous waste entering

combustion feed streams as an

alternative to or supplement to end-ofpipe emission controls. With respect to

hazardous waste burning incinerators,

LWAKs and cement kilns, EPA includes

in the definition of ‘‘process changes’’

the following activities: equipment or

technology modifications, reformulation

or redesign of products, substitution of

raw materials, improvements in work

practices, maintenance, inventory

control, and environmentally sound

recycling measures which reduce the

amount and/or toxicity of hazardous

waste entering feed streams of

combustion devices. The term

environmentally sound recycling

includes on-site (including closed-loop

recycling) and off-site recycling

activities that use, reuse or reclaim

hazardous materials in accordance with

EPA regulations. Burning for energy

recovery is not included in the meaning

of ‘‘process change’’ as a basis for

requesting a one year extension for

waste minimization purposes. This

proposed definition would apply only

to hazardous waste burning

incinerators, LWAKs and cement kilns.

The Administrator or a State that has

an approved part 70 permit program (or

has been delegated the authority to

implement and enforce the emission

standard for that source) may grant

extensions under 40 CFR 63.6(i)(9).

Under this approach, decisions to grant

one year extensions will be made by

EPA Regional offices and approved or

delegated state programs. EPA

recognizes that States employ a variety

of approaches for requiring or

encouraging the consideration of waste

minimization measures in achieving

compliance with regulatory

requirements. It is not appropriate for

EPA to supersede State approaches with

a uniform set of criteria for evaluating

waste minimization requests for one

year compliance extensions. However,

EPA believes it is appropriate to

encourage (but not mandate)

consistency in how these decisions are

made. Therefore, EPA is requesting

comment on a proposal to include four

factors that must, at a minimum be

considered by EPA Regional offices and

approved or delegated state programs in

approving or denying requests for one

year compliance extensions for

hazardous waste burning incinerators,

LWAKs, and cement kilns). These

factors include:

• The extent to which the process

changes (including waste minimization

measures) proposed as a basis for the

extension reduce or eliminate hazardous

wastes entering combustion feed

streams and are technologically and

economically feasible.

• Whether the magnitude of the

reductions in hazardous wastes entering

combustion feed streams through

process changes are significant enough

to warrant granting an extension.

• A clear demonstration that

reductions of hazardous wastes entering

combustion feed streams are not shifted

as increases in pollutants emitted

through other regulated media.

• A demonstration that the design

and installation of process changes,

which include waste minimization

measures, and other measures that are

necessary for compliance cannot

otherwise be installed within the three

year compliance period.

These factors will provide a degree of

consistency, while still allowing

flexibility among EPA Regional offices

and approved States, in the use of this

innovative regulatory approach. EPA

will also provide separate guidance that

provides examples of how to apply the

factors to consider and additional

information that will be helpful to

government and regulated entities. For

example, the guidance will provide

examples that will help gauge whether

the magnitude of proposed requests to

reduce hazardous wastes entering

combustion feed streams through

process changes are significant enough

to warrant granting an extension. For

example, companies that commit to a

25% or greater reduction in hazardous

wastes entering combustion feed

streams may be more likely to be

considered for an extension than

companies that commits to only a five

percent reduction.

EPA anticipates that the guidance will

contain other examples on how to

evaluate cases where a low percentage

reduction may actually reflects a

significant improvement relative to

previous significant waste minimization

achievements. The guidance will

address how to evaluate shifts from

combustion feed streams to other

regulated media, such as wastewater

effluents or other pollutant sources. EPA

anticipates the guidance will address

assuring that the proposed process

changes that include waste

minimization measures are critical path

steps toward compliance, and not

process improvements that have little to

do with reductions of hazardous waste

feed streams, and could otherwise have

little impact on compliance. Waste

minimization measures that are not on

a critical path toward compliance or

that do not have a direct impact on

reducing or eliminating hazardous

waste streams entering combustion feed

streams are not good candidates for a

one year extension. Finally, EPA

anticipates the guidance will include a

list of states that have approved part 70

permit programs, a list of states that

operate waste minimization technical

assistance programs, and a list of States

that have mandatory or voluntary waste

minimization planning programs.

EPA also points out that companies

that choose to apply for a one year

extension for waste minimization

purposes may wish to coordinate the

development of compliance extension

applications with the development of

‘‘public regulatory notifications of intent

to comply,’’ contained in today’s rule,

since much of the developmental work

for the two actions should be nearly

identical.

In the comments received, several

companies and states said that, in some

cases, even the three year compliance

period plus a one year extension would

not be adequate time to design, and

install waste minimization measures or

additional combustion or treatment

measures necessary to ensure

compliance with the MACT standards.

It may be appropriate, under the

circumstances described below, to grant

facilities who demonstrate that longer

than three years plus a one year

extension is necessary to implement

waste minimization measures that

significantly reduce the amount and/or

toxicity of hazardous waste entering

combustion feed streams additional

time (i.e., longer than four years).

Reducing the amount of hazardous

waste entering combustion feed streams

provides greater long-term levels of

protection for public health and the

environment than other non-waste

minimization/pollution prevention

measures that could be used to comply

with the MACT standard. Since

facilities that need longer than three

years or the three year date plus a one

year extension to meet compliance are

technically in violation (not including

facilities that are granted a one year

compliance extension and meet

compliance within the one year

extension period), EPA will require

these facilities to enter into written

consent agreements/consent orders (CA/

COs) to receive this additional time. The

process changes that include waste

minimization measures must clearly

demonstrate the facility will achieve

significant reductions in the amount of
24248 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

hazardous wastes entering combustion

waste streams over what would have

otherwise have been combusted over the

long term using combustion-based

compliance alternatives installed within

the three year compliance period (or

three years plus a one year compliance

extension). EPA encourages facilities to

consider undertaking longer-term waste

minimization compliance approaches,

subject to limitations proposed today.

EPA will consider such requests using

its enforcement discretion and the

principles articulated in the Agency’s

‘‘Policy on Encouraging Self-Policing

and Voluntary Correction’’ (60 FR

66706, December 22, 1995) (i.e., the

‘‘Audit Policy’’). Within this context,

EPA may, in certain cases, consider a

reduction of penalties for facilities that

are able to install compliance solutions

that demonstrate significant reductions

in hazardous wastes entering

combustion feed streams, but need

additional time beyond that allowable

under the regulations.

To qualify for this special

consideration for additional time, a

regulated entity would have to submit a

written request that contains the

information listed below. Facilities must

submit requests to the EPA Regional

Office that has oversight for their facility

within one year after the MACT

standards for this rulemaking are

promulgated. The request would

include:

• An explanation of why the facility

cannot reasonably implement their

proposed process changes that include

waste minimization measures within

four years from the date of the

promulgation of the MACT standards.

• An explanation of how the facility’s

proposed process changes (that include

waste minimization measures) will

achieve greater reductions in quantity

and/or toxicity of hazardous wastes

entering combustion feed streams. The

proposed reductions must be

significant. EPA will make these

determinations on a case-by-case basis.

• An explanation of how the waste

minimization/pollution prevention

measures are necessary to achieve

compliance with the MACT standards

(i.e., waste minimization measures

which reduce hazardous wastes entering

combustion feedstreams must be shown

to have a direct impact on the

subsequent design, installation and

testing of combustion or other treatment

measures necessary to achieve and go

beyond compliance standards), and a

schedule for implementation of the

proposal.

• A waste minimization facility plan.

This plan must follow EPA’s ‘‘Pollution

Prevention Facility Planning Guide’’

(May, 1992; NTIS # PB92–213206), or, if

the facility is located in a State that

requires mandatory waste minimization

planning, the form of waste

minimization planning required by that

State.

Regulated entities must demonstrate a

clear intent to achieve compliance in a

timely fashion by entering into a

consent agreement/compliance order

with EPA as soon as they exceed the

allotted time provided by the

regulations (including any regulatory

extension). EPA would then exercise its

enforcement discretion to treat a

facility’s failure to achieve compliance

by the regulatory deadline as a violation

that can receive penalty mitigation

under the Agency’s Audit Policy. Under

the Audit Policy the Agency may give

up to a 100% reduction in the gravity

based component of potential penalties.

To qualify for eliminating the gravitybased penalty a facility will have to

show that it has a compliance

management program that meets the

criteria for due diligence under the

Audit Policy. Otherwise, the facility

may qualify for a 75% reduction of the

gravity component of the penalty. EPA

will provide examples of past cases in

the supplemental guidance noted earlier

in this section.

EPA realizes that some waste

minimization compliance measures may

be more cost effective than combustion

based approaches. EPA will retain its

discretion to recover any economic

benefit gained as a result of

noncompliance. This will ensure that

facilities that delay compliance for a

specific period of time do not receive an

economic benefit during the period of

non-compliance over regulated entities

that do comply within the regulatory

deadline. For example, EPA may

recover the economic benefit a company

receives by delaying capital

expenditures for modifying their

manufacturing process to meet the new

compliance standards. EPA may

exercise its discretion in appropriate

circumstances to choose the lower

figure between: (1) the company’s

pollution prevention/waste

minimization expenditures, and (2)

expenditures the company would have

incurred implementing other methods

to come into compliance, when

calculating economic benefit during the

period of non-compliance with the new

regulatory standards. EPA will also use

its enforcement discretion to waive

recovery of insignificant amounts of any

economic benefit resulting from a

facility’s delayed compliance.

EPA is also encouraging companies to

pursue waste minimization measures in

an expansion of the provision in the

Clean Air Act regulations that requires

facilities to submit an early notification

that they intend to comply with the

MACT standards as they become

effective (usually about 2–3 years after

the notification is submitted). The

expansion, called a public regulatory

notifications of intent to comply, would

require facilities to include substantially

more detail in this notification on: (1)

What they have considered doing to

meet the MACT standards (particularly

with respect to waste minimization);

and (2) how they have decided to

proceed. This expanded notification

would be sent not only to the regulatory

agency, but would also be made

available to the local community. In

addition, the facility would be required

to hold an informal meeting with the

local citizenry to discuss the

notification. However, regulatory agency

review and approval of the notification

is neither mandated nor expected. This

approach would harness the power of

public opinion to urge facilities to

consider waste minimization

alternatives to end-of-pipe ways of

meeting the MACT standards. This

approach is described in detail

elsewhere in today’s NODA for public

comment.

EPA requests comment on the extent

to which the proposed one year

compliance extension, the proposed

opportunity for companies to enter into

consent agreements/consent orders for

periods that extend beyond four years,

and the PRNIC approach provide

companies with appropriate incentives

to pursue waste minimization measures

to achieve compliance.

VI. Permit Requirements

A. Coordination of RCRA and CAA

Permitting Processes

In the NPRM, EPA proposed to place

the final MACT standards in 40 CFR

Part 63 and reference those standards in

40 CFR Parts 264 and 266 (61 FR at

17451). Under this proposal the

standards would only be written out in

the CAA regulations, but they would

legally be part of both the CAA and

RCRA regulations. Thus, both programs

would have an obligation to address the

standards in permits issued under their

authority. EPA proposed this approach

to provide the maximum amount of

flexibility for state permitting

authorities to coordinate the issuance of

permits and enforcement activities in a

way which most effectively addresses

their particular situation.

After reviewing the NPRM comments,

there is some question on whether the

proposed approach will provide the

maximum amount of flexibility to the
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24249

state permitting authorities. The

proposed approach would still require

in most cases at least two different

permitting authorities to review the air

emission standards in a permit. Since

under the original proposal the

standards would be in both the RCRA

and CAA regulations, permit writers

from each program might be required to

address them to some degree in a permit

under that program, either by writing

them directly in the permit or by

referencing them from the other permit.

The proposed approach might not have

given states the flexibility to implement

the new standards under a single

regulatory program. Thus, the proposed

approach would result in duplicative

permitting actions in many cases.

Commenters had several other

concerns with an approach where the

air emission standards are incorporated

into two permits. One major problem

described by commenters is that the

overlapping permit conditions of the

Title V and RCRA permits would be

subject to two separate permit

modification procedures, administrative

appeals procedures, and potentially

separate judicial procedures as well.

The Agency now believes that this

outcome could be needlessly

duplicative and unwieldy, and therefore

not consistent with the Agency’s intent

to simplify permitting.

Additionally, commenters were

concerned that the proposed approach

would have allowed for dual

enforcement scenarios where

enforcement actions under both statutes

would be brought against the facility for

a single violation. In the NPRM, EPA

stated that the Agency did not expect to

enforce under both permits (61 FR at

17452). However, commenters noted

that this statement did not restrain the

states from initiating dual enforcement

actions, or citizens from initiating dual

citizen suits.

Codifying the MACT standards in

only one place in the regulations (unlike

the proposed scheme) may actually

provide states the greatest flexibility in

the way they issue permits and prevent

duplication of effort. Although the

standards would be codified under one

statute, states could decide which

program they want implementing the

standards. A state would be free to

decide, for example, to have its RCRA

staff implement a set of CAA standards.

Another approach would be for a state

to decide under which state statute to

adopt the MACT standards based on

which part of their program they wish

to implement the standards. For

example if EPA places the MACT

standards in part 63 only (see below), a

state could still decide to adopt those

standards under their state solid waste

statute and implement the standards

through their RCRA hazardous waste

program, depending on how their state

solid waste statute is written. The basic

premise in this approach is that it is not

significant to EPA, nor to proper

implementation of RCRA or CAA, under

what statute a state adopts a RCRA or

CAA regulation.

EPA particularly would like to take

comment on this issue. Do states believe

they can decide under which program to

implement the MACT standards if they

are only placed in Part 63? EPA is

concerned that states be allowed to

implement the standards through either

their CAA or their RCRA program,

whichever works best for their

particular situation.

Currently, EPA is considering placing

the MACT standards only in 40 CFR

part 63 and relying on the air program

implementation scheme, including the

Title V permitting program, to bring

facilities into compliance with the new

standards. This approach (as opposed to

the converse—placing the standards

only in the RCRA regulations) is the

only approach that appears feasible to

allow the standards to be codified in

only one place in the regulations. The

Agency would rely on the integration

provision of RCRA section 1006(b)(1) to

defer RCRA controls on these air

emissions to the part 63 MACT

standards. (The CAA does not have a

similar integration provision which

would allow deferral of CAA

requirements to RCRA regulations.)

We emphasize, however, that under

this approach, there would still be a

need for a RCRA permit at HWC

facilities, to address any other RCRA

units on site, and to address RCRA

regulations which apply to all types of

RCRA facilities and which are not

duplicated under CAA. For example, a

permit will be required to address

hazardous waste storage units that hold

the waste prior to combustion. As with

all RCRA permits, the permit would

require compliance with the standards

in 40 CFR part 264 (including general

facility standards, preparedness and

prevention requirements, contingency

planning and emergency procedure

requirements, manifesting requirements,

recordkeeping and reporting

requirements, releases from solid waste

management units requirements, closure

and post-closure requirements, financial

requirements, corrective action

requirements, storage requirements,

materials handling requirements, and

air emissions standards for process

vents, equipment leaks, tanks, and

containers). The omnibus provision of

RCRA Section 3005(c)(3), codified at

§ 270.32(b)(2), which provides for

additional permit conditions as

necessary at a particular site to protect

human health and the environment,

would also need to be addressed in the

RCRA permit, with respect to the

combustor and other activities at the

facility. (This issue is discussed further

in the next section.) Among other

consequences, this means that the

current program of processing RCRA

HWC permits will continue until EPA

finalizes any program changes. It

remains a high priority to bring all HWC

under full Part B permits as soon as

possible.

Although the RCRA permit would not

need to duplicate the MACT controls

contained in a Title V permit, there will

typically be a number of waste

management activities associated with

the combustion unit that would need to

be addressed in the RCRA permit (and

not the Title V permit), such as

materials handling (feed and residues)

and combustor-specific (but not MACTrelated) waste analysis requirements

and feed restrictions. If, as under the

original proposal, the Agency decides to

retain the DRE standard in the RCRA

regulations, then DRE would also need

to be addressed in the RCRA permit.

The discussion above describes one

approach the Agency is considering for

the final rule. If this approach were

adopted, it would establish how EPA

would implement the new MACT

standards where the Agency has

permitting jurisdiction. However, in

many cases, states are delegated RCRA

and CAA authority. It would therefore

be up to the state program to decide

how best to implement the MACT

standards given the particular

authorities of the state. The approach

described today may be better suited to

provide greater flexibility for state

approaches, whether the State prefers to

rely primarily on the MACT and Title V

permit process or the RCRA permit

process to impose the new standards.

The Agency recognizes that in many

cases facilities will already have a RCRA

permit in place when the MACT

standards become effective. This

situation raises the question of what

happens to RCRA permit conditions

related to combustor air emissions.

From an overall standpoint, it is

expected that the MACT standards will

be more stringent than many current

RCRA regulations and permit

conditions. However, at some

individual sites, certain RCRA permit

conditions may be more stringent than

the corresponding MACT emissions

standards. Some potential reasons why

such a situation would occur are

because the RCRA permit condition is
24250 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

based on a site-specific risk evaluation

under the BIF rule or the omnibus

provision; because the MACT standard

is in a different format than the permit

condition (e.g., a mass emission rate or

removal efficiency format in a RCRA

permit vs. a concentration-based

standard for HCl under MACT) and at

that particular site the RCRA format

yields more stringent control; because,

in the case of CO limits in early

incinerator permits, the RCRA permit

limit was based on levels during the

trial burn; or because the facility was

one of the lower emitters in the

standards development MACT pool.

The Agency’s overall intent is for the

MACT standards to replace the RCRA

air emissions standards for hazardous

waste combustors. Therefore, where the

Agency has permitting jurisdiction, the

RCRA air emissions permit limits for

HWCs, with the exception of sitespecific risk-based limits, would be

deleted from RCRA permits when the

MACT standards become operational. In

the case of site-specific risk-based

limits, based either on the BIF metals

and HCl/Cl2 requirements or omnibus

authority, these limits would remain in

RCRA permits to satisfy the

protectiveness requirement of RCRA

section 3004 (a) and (q). As with EPA

issued permits, in authorized states any

site-specific risk-based limits would

need to be retained where necessary to

satisfy RCRA protectiveness

requirements. Since authorized states

are allowed to be more stringent, states

will determine, in the process of

deciding whether to delete old RCRAbased regulations and in the permitting

process, whether to keep or delete more

stringent permit conditions which are

not based on a site-specific risk finding.

EPA would like to take comment on

the approach of placing the MACT

standards only in the part 63

regulations, and deferring the RCRA

standards, as described above.

B. Permit Process Issues

As discussed above, the Agency is

considering an approach of placing the

MACT standards only in 40 CFR part 63

and using RCRA 1006(b) authority to

defer RCRA permitting to the Title V

permitting program for the air emission

standards only. This approach raises the

issues of how and when the permitting

authorities should modify existing

RCRA permits to remove the air

emission standards. The Agency’s

current thinking is that the RCRA

permit should continue to apply until a

facility completes its comprehensive

performance testing and its Title V

permit is issued (or its existing Title V

permit is modified to include the MACT

standards). The RCRA permit would

then be modified to remove the air

emission limitations which are covered

in the Title V permit. Another option is

to modify the RCRA permit at the time

the facility submits their comprehensive

performance test results. However, it is

beneficial to wait until the test results

are reviewed, approved, and written

into a Title V permit before deleting any

RCRA permit conditions because of the

greater level of Agency and public

review that occurs during the permit

process. The Agency would like to take

comment on this issue. At what point

should the RCRA permit be modified to

remove air emission standards? How

should the switch-over to the new

permitting system occur? Note that

irrespective of when the Title V permit

is issued/modified, the MACT standards

and associated operating limits become

enforceable according to the schedule in

the final rule.

After the compliance date for the final

rule, but before the RCRA permit is

modified to remove any air emission

limitations, there will be a period where

a facility will have both a RCRA permit

that addresses air emissions and either:

(1) A precertification of compliance

document with applicable operating

conditions that they have submitted; or

(2) a Title V permit which also

addresses air emissions. Note, the RCRA

permit will continue to apply until such

time that it is modified to remove any

air emission limitations. The

precertification of compliance

document or Title V permit will not

automatically supersede RCRA permit

conditions as a matter of law. The more

stringent conditions will govern.

C. Omnibus and RCRA/CAA Testing

Coordination

As discussed in the preamble to the

proposed rule (61 FR at 17371), EPA

currently has a national RCRA policy of

strongly recommending to all federal

and state RCRA permit writers that,

under the omnibus provision of RCRA

section 3005(c)(3), site-specific risk

assessments (SSRAs) generally be

performed as part of the RCRA

permitting process to determine

whether additional conditions are

necessary to protect human health and

the environment. The results of these

risk assessments are then used to set

protective permit conditions. Under the

new permitting scheme that the Agency

is considering (placing the MACT

standards only in 40 CFR part 63), the

Agency is considering when the RCRA

omnibus provision would continue to

be used—for example, to require a sitespecific risk assessment—and the timing

of the RCRA omnibus finding in relation

to the Title V permit issuance/

modification.

As discussed in the NPRM, the

Agency has indicated a preference for

modifying our current policy of

recommending that a site-specific risk

assessment (SSRA) be performed during

permitting at hazardous waste

combustors in most cases (61 FR at

17372). Depending on the scope and

level of the final MACT standards, this

policy may need to be re-evaluated. For

at least some facilities, there might still

be sufficient cause to perform a SSRA

under the RCRA omnibus permitting

authority.

Thus, the Agency is also considering

the timing issue of whether a RCRA

omnibus finding would be expected to

occur at the same time as the Title V

permitting decision (or the Title V

permitting modification decision, if this

is more appropriate, since some of these

units will most likely already have Title

V permits). The Agency expects that

many of the trial burns to support

SSRAs will already be completed prior

to the effective date of the MACT rule,

and would not need to be repeated

provided none of the resulting

emissions limitations are relaxed based

on the MACT rule. For facilities where

trial burns for risk assessments have not

been performed, a RCRA omnibus

determination as to whether a SSRA is

needed can be made in most cases

before the comprehensive test protocol

is finalized. This situation would allow

the MACT comprehensive test protocol

and RCRA trial burn plan to be

coordinated with respect to sampling

and analysis procedures and operational

protocols. However, the Agency does

not plan to hold up comprehensive

performance test approval or the Title V

permit process (modified or new

permits) to accommodate a RCRA

omnibus finding.

If it were not possible to make the

RCRA omnibus determination in

sufficient time to allow coordinated

emissions testing, then a separate RCRA

trial burn might be necessary. This

separate test event would increase the

costs to the facility and require more

oversight by the permitting authority.

After allowing for additional time to

perform a SSRA, the findings of the risk

assessment could then be used to

establish site-specific standards which,

in turn, might require a review of the

Title V permit and its associated

operating limits/standards.

It should also be noted that if the DRE

standard is retained under RCRA (see

discussion in Section III.A.), these same

testing coordination issues apply to DRE

testing. (At sites where SSRAs are to be

performed, it is expected that DRE
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24251

68Wastes with energy value greater than 5000 Btu

may generally be said to be burned for energy

recovery, since this is the Btu value of low grade

fuels. 48 FR 11157–59 (March 16, 1983). However,

lower energy wastes could conceivably be burned

for energy recovery in industrial furnaces, such as

cement kilns, or in industrial boilers due to these

devices’ general efficiency of combustion. Id. At

11158. Thus, the 5000 Btu level is not an absolute

measure of burning for energy recovery (i.e., a rule),

particularly when industrial furnaces and industrial

boilers are involved.

testing and testing necessary to provide

data for SSRAs will be occurring at the

same time.)

We invite comment on the

workability of this approach for

achieving maximal coordination of the

RCRA trial burns and omnibus findings

with the initial MACT comprehensive

test and Title V permitting.

Part Four: Miscellaneous Issues

I. 5000 Btu per Pound Policy for Kiln

Products

Current Agency policy exempts

cement product (clinker) from cement

kilns burning hazardous waste from

regulation as a hazardous waste

provided the fuel value of the hazardous

waste exceeds 5000 Btu per pound 68.

This allows cement kilns to burn highBtu hazardous waste for energy recovery

purposes and still market the clinker

and the cement mix produced from the

clinker as commercial product free from

any Subtitle C concerns. The Agency

has already provided a clarification (53

FR 31198, August 17, 1988) that the

regulations for ‘‘waste derived

products’’ at § 266.20 do not apply to

products from processes using

hazardous waste (HW) fuels, unless

these processes also use hazardous

wastes as ‘‘ingredients’’ in a product

destined for land application (i.e., the

product must ‘‘contain’’ the HW as an

ingredient to be covered by § 266.20) or

burn hazardous waste for destruction.

To implement this regulation, the

Agency has used Btu values of a waste

as a proxy to determine whether

contaminants in the HW fuels will or

will not be deemed to transfer to the

product (i.e., become ingredients). Over

time, many commenters have submitted

data and have suggested that the heat

content of a waste is an indirect and

imprecise way of identifying whether

materials should be subject to the

provisions of § 266.20 (hazardous

wastes used in a manner constituting

disposal).

The Agency has been interested for

some time in considering whether and

how to change the existing Btu

approach. For example, 60 FR 7376

(February 7, 1995) discusses a possible

exclusion of clinker from the derivedfrom rule, even when cement kiln dust

is introduced in the feed. EPA has also

discussed with CKRC the narrower issue

of whether the 5000 Btu/lb energy value

level reliably predicts whether toxic

contaminants would more likely

partition to the clinker and ultimately

the cement product. Some from industry

have suggested that a facility that agrees

to limit waste feed metals to their

‘‘historic average’’ could be exempted

from the 5000 Btu/hr policy. The

rationale is that even if the facility took

lower Btu waste, they would not be

taking higher quantities of metal waste

than currently, at least on the average.

This would address EPA’s concern

about allowing an increase of metals in

HW fuels burned by cement kilns if the

5000 Btu restriction were abandoned.

Today, without our endorsement at

this time, the Agency is offering this

concept and some potential variations

for public comment. The Agency is

interested in the possible ramifications

and requests comment, particularly with

respect to limiting the concentrations of

metals in cement products from cement

kilns burning hazardous waste. To take

advantage of such a policy, a facility

would have to establish a baseline of

metals feed in the hazardous waste (for

example, the average of the previous

three years) and then agree to

enforceable permit conditions limiting

metals feedrate levels to that average

plus one standard deviation.

Presumably, enforceable restrictions on

metal feed rates should control metal

partitioning to clinker and CKD much

more effectively than would the Btu

limit and ensure that these materials

would not contain an increase in toxic

metal constituents from the hazardous

waste used as fuel. Also, metal feed

limits based on a historical average

would appear to be more stringent than

the current BIF metal feed limits, which

are set on a health basis considering

direct inhalation of metals emissions.

(In other words, as discussed in earlier

sections of this notice, cement kilns are

generally feeding metals far below

allowable BIF limits.)

EPA seeks comment on allowing

cement kilns (and LWAKs) the option of

complying with the following, which is

only partly based on the suggestions

discussed with cement kiln

representatives, with some additions:

• An owner or operator of a cement

kiln burning hazardous waste would be

allowed to burn hazardous waste with

any Btu content, provided the owner or

operator agrees to enforceable hazardous

waste feed operating limits on metals of

concern (see below);

• These metals feed limits would be

set at levels that would ensure, at least

on an annual basis, that metals on a

mass basis do not increase over current

levels, which are substantially less than

those allowable under BIF (and sources

would, of course, remain subject to

stack emission standards to control the

emission of metal HAPs);

• Feed limits would have to be

established for each of the following

twelve metals: antimony, arsenic,

barium, beryllium, cadmium,

chromium, cobalt, lead, nickel,

selenium, thallium, and vanadium;

• Sampling and analysis would be

conducted as often as necessary to

document that the metals levels are

below the limits and included in the

facility’s waste analysis plan required

by 40 CFR 264.13; and

• Results of the analysis would have

to be available for public inspection.

Also, the Agency is considering a

variation of this option, under which

kiln operators would have to achieve

specified percentage reductions of the

total quantity (on an aggregate basis) of

the following metals in their wastes

combusted: antimony, arsenic, barium,

beryllium, cadmium, chromium, cobalt,

lead, nickel, selenium, thallium, and

vanadium. EPA chose these particular

metals based on their potentially high

human health and ecological risk in

conjunction with their significant

tendencies to persist in the environment

and accumulate in living tissue. If

generators reduce metals in wastes over

time, holding kilns to the average of the

past three years may actually allow

increased burning of certain metalbearing streams. This is because other

streams may contain less metals. In

contrast, commitments to reducing

metals below baseline limits would

ensure that progress continues in waste

minimization. EPA requests comments

on this option, including information

about: (1) The prevalence and

distribution throughout industry sectors

of waste streams bearing these metals

sent to combustion, and (2)

opportunities for generators to reduce

these metals in wastes sent to

combustion by means of source

reduction during generation.

EPA requests comment on the impact

of imposing limits on metals

concentration on waste streams

combusted in cement kilns. EPA raises

these questions:

• How much hazardous waste now

sent to cement kilns for energy recovery

would be likely to meet such metal level

limitations?

• Of the fraction of wastes that would

‘‘fail’’ a metals limit, would generators

of waste now sent to cement kilns

reduce metals concentrations in these

wastes, using waste minimization and

pollution prevention, so that cement
24252 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

69 Another potential reading of the Section

260.10 definition is that ‘‘foundry furnaces’’ only

applies to a furnace that burns a primarily metalbearing material. Under this reading, TRUs could

not be industrial furnaces because they burn sand

with only contaminant levels of metals. However,

since TRUs are closely associated, both physically

and functionally, with the primary metal processing

functions of a foundry, they are appropriately

classified as industrial furnaces subject to part 266,

subpart E.

kilns would continue to receive the

same amounts of waste?

• If no such action to reduce metals

concentrations occurred, would cement

kilns reject high-metals hazardous

wastes now sent to cement kilns for

energy recovery and would these wastes

go instead to incinerators?

The Agency also requests comment on

the related issue of appropriate metals

reduction goals. EPA has identified a

national goal for waste minimization of

the most persistent, bioaccumulative

and toxic hazardous constituents by 25

percent by the year 2000 and by 50

percent by the year 2005. See EPA’s

Waste Minimization National Plan

(Office of Solid Waste, November 1994).

Consistent with this national waste

reduction goal for metals, EPA requests

public comments today on requiring

aggregate percentage reductions for the

twelve metals in waste feed, as an

alternative to holding cement kilns to

the historical average feed limits of the

past three years and allowing no

increases over baseline limits. This

approach would also further waste

minimization planning by offering kilns

a reason to motivate the generators

supplying them with hazardous waste

for combustion to undertake waste

minimization. In comments related to

the role of waste minimization in the

MACT proposal, Molten Metal

Technologies (MMT) states that

‘‘without drivers favoring pollution

prevention and waste minimization in

the instant rulemaking, only minimal

progress will be made.’’ MMT points out

that economics conspire against

pollution prevention and waste

minimization since investment for

compliance often takes priority over

investment for process modifications to

reduce waste generation and since

corporate rate-of-return thresholds may

‘‘squash’’ pollution prevention and

waste minimization initiatives.

Finally, the Agency requests comment

on whether additional nonmetal

constituents (e.g., chlorinated organics)

should also be identified for similar

reductions as part of this approach.

II. Foundry Sand Thermal Reclamation

Units

A. Background

Foundry operations can generally be

classified as either ferrous or

nonferrous, depending on their primary

feed materials. Both types of foundries

use large amounts of sands for their

metal molds. Over time, the sands

become contaminated with the metals

being used, as well as with certain

binder materials. Nonferrous foundries

(i.e., brass, lead, etc.) sometimes

generate spent sands that exhibit the

Toxicity Characteristic (40 CFR 261.24)

for lead or cadmium. (The Agency has

indicated concerns with certain sand

treatment methods. See 62 FR 10004,

March 5, 1997.) These sands can be

physically processed to remove

contaminants for continued use,

resulting in less sand use for the

foundry, and less need for disposal of

the sands. Interest has also been

expressed in using thermal processing

or reclamation units (TRUs) to clean the

sand for continued use. TRUs may

represent a significant waste

minimization technology for the

foundry industry.

The TRUs remove contaminants

primarily by combusting the organic

binder materials in the sand. These

organic materials are generally wax-like

materials, synthetic or natural (e.g.,

clays, phenols, etc.). Air emissions

concerns would include lead, cadmium,

and particulate emissions, as well as

products of incomplete combustion.

These units are identified as industrial

furnaces under 40 CFR 260.10 as a type

of ‘‘foundry furnace’’ and are subject to

regulation under 40 CFR part 266,

subpart E (the ‘‘BIF rules’’) when they

burn hazardous waste.69 When the

Agency developed subpart E, however,

we did not consider whether TRUs

would be appropriately controlled

under those standards. The Agency

created a special exemption for metal

recovery furnaces under § 266.100(c)

and also proposed a special exemption

for petroleum catalyst recovery units

(see 60 FR 57780; November 20, 1995).

In these two cases, we found that the

BIF rules would not appropriately

control the units in question, i.e., any

air emissions hazards might be more

appropriately controlled under

standards specially designed for those

units under either RCRA or CAA. Under

RCRA Section 1006, an important

consideration for the Agency is to avoid

duplication to the extent practical

between the two Acts. Also, as noted

above, TRUs may achieve significant

waste minimization benefits, an

important consideration under RCRA.

B. Deferral and Variance Options for

Consideration

The Agency is presently developing

MACT controls under the CAA for

foundries. Although at this time it is not

clear to what extent TRUs would be

subject to MACT controls,

representatives from the foundry

industry have suggested that, as the new

MACT rules are implemented, all

foundries with TRUs will be required,

as a practical matter, to install MACT

controls on the TRUs. Among the

reasons cited are that vendors of TRU

technology will have to design for

situations under MACT control, and

state air officials will incorporate the

MACT technology in permits for

foundries as a matter of course.

Although EPA has no way to predict

whether this scenario would come to

pass, there are obvious advantages to

controlling TRUs processing sands that

exhibit the TC under MACT standards,

as opposed to under the BIF rules.

These advantages include

administrative simplicity and maximum

flexibility for implementing agencies.

EPA requests comment on the following

two approaches to ensure appropriate

controls for TRUs:

1. Deferral option. Given the

developments under the CAA discussed

above, and also in light of the potential

waste minimization benefits, EPA

requests comments on appropriate

control schemes for TRUs burning

hazardous foundry sands. Specifically,

comments are requested on a deferral of

BIF applicability, similar to the existing

provision for metal recovery furnaces

and proposed provision for petroleum

catalyst recovery units. This would

allow development of the foundry

MACT, and potentially the eventual

application of these controls to TRUs

processing sands that exhibit the TC.

Under such an approach, EPA would

place an exemption in Part 266, Subpart

E, identifying foundry TRUs as an

exempt BIF, and a one-time notice

would be required as is now required

for metal recovery furnaces under

§ 266.100(c)(1)(I).

2. Variance from definition of solid

waste option. TRUs appear to be integral

to foundry operations. They are located

at the foundry site, operated by the

foundry, and the sand being processed

and returned to the foundry operation is

essential in the manufacturing

operation. The time periods between

when a spent sand is generated and

when it is processed and returned is

typically a matter of hours. In fact, TRUs

may reduce the need to store spent

sands for processing and may thereby

reduce fugitive emissions of the sands
Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules 24253

70The Agency notes that, typically, a variance

from the definition of solid waste under 260.31(b)

would apply at the point of generation (e.g., in this

case, the point where the spent sands are removed

from the casting forms). Also, typically, when such

a variance is granted, the variance is only

applicable to those secondary materials that meet

the conditions of the variance (e.g., the variance

would not include secondary materials that are not

reused in the production process).

The normal and efficient flow of materials at

facilities with a TRU may involve the processing of

all of the spent sand generated. However, after

recovery of the sand, insubstantial amounts of

sands that are processed by the TRU may be found

to be unusable again as foundry sand, and so may

be discarded. While treatment and disposal of the

spent foundry sand is clearly not the intent of the

TRU, ‘‘treatment and disposal’’ would be the

regulatory status of any hazardous secondary

material that is processed such that it is no longer

hazardous and then discarded, given the most

straightforward reading of the regulations.

Nevertheless, the Agency believes that because

the TRU is typically integrated into the facility’s

operations, and the flow of spent foundry sand into

the TRU becomes a standard operating procedure,

the incidental discard of an insubstantial amount of

spent foundry sand should not overshadow the

basic purpose of § 260.31(b) to grant a variance from

the definition of solid waste to materials that are

reclaimed and reused in the production process,

where such reclamation is, in effect, an integral step

in the flow of production. Thus, the Agency asserts

that, assuming all other conditions of the

§ 260.31(b) variance are met, the fact that a

relatively insignificant amount of spent foundry

sand is discarded would not negate a variance

granted to spent foundry sand, or require a

treatment permit for the TRU.

71See also 50 FR 49164, 49171 (Nov. 25, 1985);

52 FR 16982, 17021 (May 6, 1987); and 56 FR 7134,

7203–04 (Feb. 21, 1991) which discuss this

question, although inconclusively.

that might result from physical

processing. Given that a sand appears

integral to foundry operations and TRUs

can greatly improve the efficiency of

sand use, EPA could conclude that even

without any rule changes, foundry

operators may be eligible for a variance

from the RCRA definition of solid waste

under the variance provisions found at

40 CFR 260.30(b), 260.31(b), and 260.33.

Under these variance provisions, EPA

(or an authorized State) may grant a

variance from the definition of solid

waste for materials that are reclaimed

and then used as feedstock within the

original production process in which

the materials were generated if the

reclamation process is an essential part

of the production process. This

evaluation is guided by a number of

criteria found at § 260.31(b). While

foundries certainly can and do operate

without thermally processing their

sands, and so TRUs are not literally

‘‘essential’’, as summarized above the

units do in fact greatly increase

efficiency of sand use, which is an

essential raw material of foundry

operations. Also, the TRUs are

physically proximate, and integrated

into the foundry’s operations. Emissions

from the TRUs are often ducted into

emission control devices used for the

foundries’ main production activities.

As such, the Agency could view sands

being processed in TRUs as potentially

eligible for the variance under

260.31(b) 70. EPA (or the State) would

still have to weigh the factors in

paragraph (b) on a case-by-case basis to

determine if the variance should be

granted. For example, paragraph (b)(3)

requires an examination of how the

sands are handled to ensure that losses

are minimized before reclamation. Also,

paragraph (b)(8) allows consideration of

‘‘other factors’’ as appropriate, and in

this case, air emissions controls for the

TRU would be appropriately considered

before granting a variance. As discussed

above, controls may be installed as part

of the MACT process, or simply due to

state or local air pollution laws. The

Agency would expect that as a

minimum, emissions of particulate

matter would have to be limited to

control lead emissions, and given the

organic binder compounds being

introduced to the units, limits on and

continuous monitoring of indicators of

efficient combustion, such as CO and/or

HC, would seem appropriate. Under this

approach, the Agency might or might

not develop special standards for TRUs

under RCRA or the CAA. The case-bycase approach might enable EPA and

the States to oversee the units without

the need for federal standards.

III. Status of Gaseous Fuels Generated

From Hazardous Waste Management

Activities

The proposed rule included a

proposed exclusion from subtitle C

jurisdiction for certain synthetic gas

fuels derived from hazardous waste

treatment activities (61 FR at 17465).

Some commenters stated that synthesis

gas fuels are beyond EPA’s regulatory

authority because they are uncontained

gases, and further stated that EPA had

failed to set out any explanation for its

potential jurisdiction over these

synthesis gas fuels (which jurisdiction

EPA proposed to relinquish provided

the syngas met designated

specifications).

The type of syngas discussed in the

proposal results from thermal reaction

of hazardous wastes, which reaction is

optimized to break organic bonds and

reformulate the organics into hydrogen

gas and carbon monoxide. Id. This

resulting gas can be used as a fuel at

manufacturing facilities.

EPA has broad statutory authority to

regulate fuels produced from hazardous

wastes. RCRA section 3004(q)(1); see

also Horsehead Resource Development

Co. v. Browner, 16 F. 3d 1246, 1262

(D.C. Cir. 1994) (broadly construing this

authority). The fact that syngas (by

definition) is a gas, rather than a solid

or liquid, does not appear to raise

jurisdictional issues. It is still produced

from the hazardous wastes that are

being processed thermally. See

§ 261.2(c)(2)(A) and (B) (defining such

materials as solid wastes). EPA believes

its authority to be clear under these

provisions, but will consider further

comment on the issue.71

IV. Regulatory Flexibility Analysis

The Regulatory Flexibility Act (RFA)

of 1980 requires Federal agencies to

consider impacts on ‘‘small entities’’

throughout the regulatory process.

Section 603 of the RFA calls for an

initial screening analysis to be

performed to determine whether small

entities will be adversely affected by the

regulation. If affected small entities are

identified, regulatory alternatives must

be considered to mitigate the potential

impacts. Small entities, as described in

the Act, are only those ‘‘businesses,

organizations and governmental

jurisdictions subject to regulation.’’

In preparation of the proposed rule,

EPA used information from Dunn &

Bradstreet, the American Business

Directory and other sources to identify

small businesses. Based on the number

of employees and annual sales

information, EPA identified 13 firms

which may be small entities. That

analysis also determined that the

proposed rule was unlikely to result in

detrimental impacts to small businesses.

This conclusion was derived from two

important findings:

First, few combustion units are owned

by businesses that meet the SBA

definition. Among those that are

considered small (based on number of

employees), over one-third were found

to have gross sales in excess of $50

million per year. Furthermore, available

data indicate an ongoing industry trend

toward consolidation, or market exit.

Second, small entities impacted by

the rule, were found to be those that

currently burn very little hazardous

waste, and hence face very high cost per

ton burned. These on-site facilities are

likely to discontinue burning hazardous

waste and dispose off-site, rather than

comply with the proposed rule. Based

on available data, EPA found that the

incremental cost of alternative disposal

associated with discontinued burning of

such waste would not exceed 0.10 to

0.20 percent of annual corporate gross

revenues. Furthermore, currently viable

commercial small business facilities

affected by the proposal were found to

remain profitable.
24254 Federal Register / Vol. 62, No. 85 / Friday, May 2, 1997 / Proposed Rules

The above findings indicate that the

proposed rule is expected to have

overall negligible impacts on small

entities. The Agency is currently

refining and expanding its analysis of

small entities and makes no conclusions

beyond those presented for the

Proposal.

Dated: April 22, 1997.

Elizabeth Cotsworth,

Acting Director, Office of Solid Waste.

[FR Doc. 97–11155 Filed 5–1–97; 8:45 am]

BILLING CODE 6560–50–P