Benzene Waste Operations NESHAP Waiver Guidance Document

&EPA
           United States
           Environmental Protection
           Agency
             Office of Air Quality
             Planning and Standards
             Research Triangle Park, NO 27711
EPA-453/R-93-010
January 1993
           Air
Benzene Waste Operations
NESHAP - Waiver Guidance
Document

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                                 EPA-453/R-93-010
    Benzene Waste

Operations NESHAP-

   Waiver Guidance

       Document
    Emission Standards Division
     U.S. Environmental Protection Agency
     Region 5, Library (PL-12J)
     77 West Jackson Boulevacd, 12th Floor
     Chicago, IL  60604-3590
U.S. Environmental Protection Agency
      Office of Air and Radiation
 Office of Air Quality Planning and Standard*
R«March Triangle Park. North Carolina 27711
         January 1993

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                           DISCLAIMER
This report has been reviewed by the Emission Standards Division of
the Office of Air Quality Planning  and Standards, EPA.  Mention of
trade names or commercial products is not intended to constitute
endorsement or recommendation for use.   Copies of this report are
available  through  the  Library Services Office   (MD-35),  U.S.
Environmental Protection Agency, Research Triangle Park NC 27711,
or from National  Technical  information  Services,  5285 Port Royal
Road, Springfield  VA 22161.
                                ii

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                             CONTENTS

Chapter                                                      Page

List of Figures	    yi
List of Tables	   vii

  1.0     Introduction	   1-1

  2.0     Overview of Waiver Policy 	   2-1
          2.1  Authorization	   2-1
          2.2  Goals of Waiver Policy	   2-1
          2.3  Waiver Process Overview  	   2-4
          2.4  Waiver Eligibility Criteria  	   2-5
          2.5  Waiver Period vs. Length of Compliance
               Schedule	   2-6

  3.0     Analysis and Evaluation of Compliance
          Approaches	   3-1
          3.1  Introduction	   3-1
          3.2  Determining a Source's Waiver Mitigation
               Goal	   3-1
               3.2.1  Use of TAB to Estimate Lost Benzene
                      Emissions	   3-6
               3.2.2  Estimates Based on Fraction Emitted .   3-8
          3.3  Actions a Source May Take to Achieve
               Mitigation Credit  	  3-10
               3.3.1  Credits for Voluntary Actions Taken
                      as a Result of Other Programs ....  3-12
               3.3.2  Categories of Mitigating Actions  .  .  3-14
               3.3.3  Restrictions on Allowable
                      Mitigating Actions  	  3-14
               3.3.4  Timing of Actions and Granting of
                      Credit	3-16
               3.3.5  Valuation of Mitigation Actions . .  .  3-19
               3.3.6  Weighting of Emission Reductions
                      Other than Benzene	3-20
               3.3.7  Calculation of Waiver Credit  ....  3-21
               3.3.8  Relationship of Waiver Actions to
                      Future Regulatory Requirements  ...  3-21

  4.0     Examples of Waiver Requests 	   4-1
          4.1  What Are the Basic Compliance
               Approaches?	   4-1
               4.1.1  Pipe the Wastes to a Unit for
                      Benzene Removal 	   4-1
                               iii

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                      CONTENTS  (continued)


Chapter

               4.1.2  Control and Use the Existing
                      Wastewater Treatment System 	   4-2
               4.1.3  Install a New, Hardpiped Segregated
                      Wastewater System 	   4-3
          4.2  Examples of Mitigating Actions 	   4-3
          4.3  Example Facilities 	   4-7
          4.4  References	4-26

  5.0     Waiver Review and Implementation	   5-1
          5.1  Waiver Application	   5-1
          5.2  Definition of Good Faith Efforts	   5-2
          5.3  Waiver Review	   5-3
          5.4  Title V Permits	   5-4
          5.5  Consent Decrees	   5-5
          5.6  Amending Waiver Agreements	   5-6
          5.7  Failure to Achieve Mitigating Benefits .  .  .   5-7

Appendices

  A       Procedures to Determine Benzene Emissions From
          Waste Operations	   A-l
          A.I  Estimates Using Fraction Emitted 	   A-l
          A. 2  Alternative Procedures	   A-4
          A. 3  References	   A-4

  B       Background Information for Reporting Wastes
          Containing Benzene  	   B-l
          B.I  What Types of Waste Streams Contain
               Benzene	   B-l
               B.I.I  Process Wastewater and Other
                      .Process Wastes	   B-l
               B.I.2  Tank Drawdown	   B-2
               B.1.3  Wastes from Maintenance and
                      Cleaning	   B-2
               B.I.4  Wastes from Waste Process
                      Turnaround	   B-3
               B.1.5  Wastes from Waste Management
                      Activities	   B-3
          B.2  What Are Common Mistakes in Reporting
               Benzene Wastes?  	   B-4
               B.2.1  Determinations Are Made Prior to
                      Treatment	    B-4
               B.2.2  Including Wastes That Have Less Than
                      10 Percent Water in the TAB  .  . .       B-4
                                iv

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                       CONTENTS  (continued)


Appendices

               B.2.3  Failure to Count Wastes Exempted
                      from Control as Part of TAB  ....    B-§
               B.2.4  Failure to Include the Benzene in
                      All Phases of the Waste	    B-5

   C      List of Environmental Regulations Affecting
          Those Facilities Under the Benzene Waste
          Operations NESHAP 	   C-l

   D      Policy for Granting Waivers of Compliance  ....  D-l

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                         LIST OF FIGURES
Number                                                       page

  3-1     Lost Benzene Emission Reduction  	  3-3
  4-1     Example - Facility 1:  Compliance Schedule With
          Benzene Reductions 	  4-9
  4-2     Example - Facility 1:  Mitigating Benzene
          Reductions	4-12
  4-3     Example - Facility 2:  Compliance Schedule With
          Benzene Reductions for 12/92 Rule  	 4-13
  4-4     Example - Facility 2:  Compliance Schedule With
          Benzene Reductions for Alternative Standard  .  . . 4-15
  4-5     Example - Facility 2:  Mitigating Benzene
          Reductions	4-17
  4-6     Example - Facility 3:  Compliance Schedule With
          Benzene Reductions 	 4-19
  4-7     Example - Facility 3:  Mitigating Benzene
          Reductions	4-21
  4-8     Example - Facility 4:  Compliance Schedule With
          Benzene Reductions 	 4-23
  4-9     Example - Facility 4:  Mitigating Benzene
          Reductions	4-25
                               vi

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                         LIST OF TABLES


Number                                                       Page


  3-1     Example Waste Data From 90-Day Report	3-7
  4-1     Summary of Air Emission Points and Controls  ...  4-5
  A-l     Estimates of Fraction of Benzene Emitted From
          Waste Management Operations  	  A-3
                               vii

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                         1.0  INTRODUCTION
      On March 7, 1990 (55 FR 8292), the EPA promulgated under
Section 112 of the Clean Air Act ("the Act"), national emission
standards for hazardous air pollutants (NESHAP) to control
emissions of benzene to ambient air from waste operations
(Subpart FF of 40 CFR Part 61).  The NESHAP for benzene waste
operations applies to owners or operators of chemical
manufacturing plants, coke by-product plants, and petroleum
refineries.  In addition, this subpart applies to owners and
operators of facilities at which waste management units are used
to treat, store, or dispose of waste generated by chemical
plants, coke by-product plants, or petroleum refineries.

      The effective date for NESHAP promulgated under the Clean
Air Act (prior to the 1990 amendments) is the promulgation date,
and unless a waiver is granted by the Administrator, existing
facilities must be in compliance within 90 days of the effective
date.  In the March 7, 1990, notice of final rulemaking for the
benzene waste operations NESHAP, the EPA noted that because of
the complexity of the controls required, and other reasons, most
facilities that must install controls would not be able to comply
with the standards within 90 days of the effective date.
Therefore, a compliance period of 2 years (to March 7, 1992) was
granted in the final standards to allow all sources to meet the
control requirements of Subpart FF.  Two years is the maximum
waiver period that may be granted under 40 CFR 61.11 (a).

      Relative to other NESHAP, Subpart FF is a complex rule that
contains complicated provisions for determining the rule's
applicability to facilities and individual waste streams within a
facility.  Following promulgation of the rule, it became apparent
to the EPA that the rule was poorly understood by the affected
facilities.  Questions and comments by the industry, consulting
firms, and local, State, and federal regulatory officials
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indicated widespread misunderstanding of many provisions of the  .
rule.  For example, a common point of confusion was how to
estimate total annual benzene quantity (TAB) for a facility, the
basic criterion that determines whether the control requirements
of the rule apply.  Several facilities had incorrectly assumed
that controls were not required and as a result would not have
been in compliance by March 7, 1992.  Based on these and other
considerations, the EPA concluded that action should be taken to
clarify the rule.  Therefore, the EPA stayed the effectiveness of
Subpart FF (57 FR 8012, March 5, 1992) while clarifying
amendments to the rule were proposed (57 FR 8017, March 5, 1992)
and promulgated.  The EPA agreed in a settlement resolving
litigation on the benzene waste operations NESHAP to take final
action on proposed amendments to Subpart FF by December 1, 1992
(See API v. EPA, No. 90-1238, Settlement Agreement, DC Circuit).
The amendments were signed by the Administrator on December 1,
1992, and were published in the Federal Register on January 7,
1993 (58 FR 3072).

      Facilities will have until April 7, 1993, which is 90 days
from the effective date (i.e., the date of publication of the
final amendments to Subpart FF in the Federal Register), to
comply with all provisions of the amended rule (40 CFR 61.05(c)).
Any facility unable to comply with the amended rule in that
period would be eligible to apply for a waiver of compliance for
a maximum period of up to two years beyond the promulgation date
(January 7, 1995), following the procedures described in the
General Provisions to 40 CFR Part 61, Section 61.10.

      As a result of comments received on the proposed
amendments, the EPA plans to propose an alternative compliance
option for Subpart FF.  The alternative compliance option, if
promulgated, would allow facilities to perform a site-specific
risk assessment to determine if they meet the risk protection
goals of the benzene waste operations NESHAP.  Owners or
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operators of affected facilities who are not meeting the
provisions of Subpart FF by April 1, 1993, and plan to use the
site-specific risk alternative compliance option, if it becomes
available, must obtain waivers of compliance.  Facilities that
plan to use the alternative compliance option are not allowed
additional time beyond the waiver period.  As prescribed in
Section 112 of the Act, once the maximum 2-year waiver period
expires on January 7, 1995, the source shall be in compliance
with Subpart FF regardless of whether the alternative compliance
option has been incorporated into Subpart FF.

      This document outlines the goals and objectives of the
benzene waste operations NESHAP waiver policy and provides
guidance for preparing, reviewing, and evaluating waiver
requests.  The guidance reflects the discussion of the waiver
policy in the preamble to the final amendments to Subpart FF (see
Appendix D).
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                   2.0 OVERVIEW OF WAIVER POLICY
2.1   Authorization
      As stated in the final stay (57 FR 8012, March 5, 1992) and
final amendments to the benzene waste operations NESHAP that were
published on January 7, 1993, (40 CFR Part 61, Subpart FF,
pursuant to the authority of Section 112 of the Clean Air Act
prior to the Amendments of 1990), the EPA will consider granting
compliance waivers under Section 61.11 of the General Provisions
of 40 CFR Part 61 to facilities that are unable to comply with
the rule by the new compliance date (April 7, 1993).  The EPA may
grant a waiver permitting a facility until January 7, 1995 (2
years after the effective date) to comply with the standards of
Subpart FF, if it is found that such a period is necessary for
the installation of controls and that steps will be taken during
the period of the waiver to protect public health (See Section
112(c)(1)(B)(ii) of the Clean Air Act as amended August 1977).

      Under the revisions to the benzene waste operations NESHAP,
the waiver of compliance is not a general (or blanket) waiver
included specifically in the standards as was the case in the
original rule promulgated in March 1990.  Under the amended rule,
each owner or operator is required to separately request a waiver
of compliance as directed in the general provisions of 40 CFR
Part 61.  However, a two-year waiver of compliance is the maximum
that may be granted by the Administrator under Section 61.11.
The waiver period is intended to give a source adequate time tp
install necessary controls and thus comply with the rule.  A
source seeking a waiver must provide the information required by
40 CFR Section 61.10(b).
2.2   Goals of Waiver Policy
      The EPA is aware that some facilities will be unable to
comply with the amended Subpart FF rules by the new compliance
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date (April 7, 1993).  This is in part a result of the long lead .
times needed to design and install the control systems necessary
to comply with the rule.  There are also facilities that
mistakenly interpreted the rule in such a way as to conclude that
the control requirements did not apply to their facility; as a
result, development of an appropriate compliance plan was
delayed.

      Another factor contributing to the inability of some
facilities to comply with the benzene waste operations NESHAP by
the new compliance date is the broad multimedia compliance
approach to environmental control being taken by some facilities.
These control strategies are designed to achieve integrated
compliance with multiple regulatory requirements.   Many of the
integrated control approaches involve major design and
construction projects (such as the installation of new wastewater
collection and treatment systems) that require several years to
complete.  The EPA recognizes that large facilities such as
petroleum refineries and chemical plants subject to Subpart FF
are also subject to a variety of other regulations addressing
releases to air, water, and land.

      One goal of the waiver policy for Subpart FF is to
encourage facilities to develop comprehensive, integrated
strategies that 1) address the environmental control needs of all
production and waste management units at a plant, 2) stress the
most efficient and environmentally beneficial long-term
solutions, and 3) incorporate pollution prevention throughout the
facility's compliance scheme, in accordance with the national
policy expressed by the Pollution Prevention Act'of 1990.
As a matter of policy and practice, the EPA defines pollution
prevention consistent with the Pollution Prevention Act of 1990
as elaborated in the Agency's 1991 Pollution Prevention Strategy.

      By granting compliance waivers, the EPA is in effect
allowing additional time for comprehensive multimedia compliance
programs to be completed.  It should be emphasized that the
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intent of the waiver policy is not to provide an easy means for
facilities to delay compliance.  Although facilities may
implement an integrated compliance approach that may require more
time than simply complying with the benzene waste operations
NESHAP alone, they must implement this approach as soon as
possible.

      Another goal of the waiver policy is to obtain mitigating
environmental benefits to compensate for benzene emission
reductions lost as a result of delayed compliance.  During the
period between the original compliance date of March 7, 1992, and
the end of the waiver period (i.e., the date the facility
actually comes into compliance with the NESHAP) the benzene
emitted from the facility's waste management operations will
exceed the quantity that would have been emitted had the facility
complied with the regulation on March 7, 1992.  The EPA considers
it essential that facilities receiving waivers make up for the
excess emissions or "lost" benzene emissions reductions.  Under
40 CFR Section 61.11(b), the Administrator may specify conditions
necessary to ensure protection of public health.  Consistent with
this provision, Subpart FF (40 CFR 61.342(b)(2)) requires that
any waiver application include an enforceable plan for mitigating
the excess benzene air emissions resulting from extending the
compliance date.  The excess benzene air emissions will be
mitigated by making additional emission reductions beyond those
required by the benzene waste operations NESHAP.

      The final objective of the waiver policy is to provide
industry and reviewers some certainty about what entitles an
applicant to a waiver.  Facilities that meet the requirements of
the waiver application as set forth in this document are assured
of receiving a waiver.  The EPA, however, is aware that some
facilities unable to comply with the benzene waste NESHAP by
April 7, 1993 may not be able to fulfill all the stated
requirements (e.g., they may be unable to provide some of the
mitigating actions deemed acceptable in this document).  In such
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cases, owners and operators are free to suggest other actions and
conditions not listed in this document as part of their waiver
application.  Acceptance of such actions or conditions is subject
to the discretion of the reviewing authority (Regional office,
State, or other delegated agency).

2.3   Waiver Process Overview
      Facilities have until April 7, 1993, to comply with the
amended rule.  Any facility unable to comply with the rule as
amended within that period is eligible to apply for a waiver of
compliance for a maximum period of up to 2 years beyond the
effective date of the final amendments (i.e., January 7, 1995).
The requirements for applying for a waiver of compliance are
described in Section 6l.lO(b) of 40 CFR Part 61.  For the benzene
waste operations NESHAP, these requirements will be implemented
as follows.  The owner/operator of an affected facility must meet
the requirements of the Subpart on April 7, 1993, or have a
waiver application approved by the appropriate EPA Regional
Office (i.e., the EPA Region or State or other delegated
authority).  As part of the waiver application, the
owner/operator must:

      a)  demonstrate the need for the waiver and explain why
          compliance will be delayed,
      b)  submit a benzene waste operations NESHAP compliance
          strategy and implementation schedule,
      c)  calculate a mitigation goal based on the benzene air
          emissions reductions not achieved because of the
          delayed compliance,
      d)  submit the information called for in the "90-day
          report" required by Section 6l.357(a) of Subpart FF
          that summarizes the regulatory status of the facility's
          benzene waste streams,
      e)  specify and commit to a series of scheduled
          environmental actions, not required under the benzene
          waste operations NESHAP or other Federal, State, or
          local regulations, that are designed to meet the
          mitigation goal.
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      Facility owner/operators awaiting the development of an
alternative compliance option can apply for a waiver; however,
they must submit a compliance strategy/schedule based on
compliance with the benzene waste NESHAP as amended on January 7,
1993.  Owners or operators must calculate mitigation goals and
credits under the waiver policy based on a plan to comply with
Subpart FF, as amended on January 7, 1993, and not based on using
the alternative compliance option.  If an additional compliance
option is promulgated, facility owners/operators may modify the
waiver and thereby reduce the mitigation goal, based from that
date forward on lost benzene emission reductions under the
alternative compliance option.  However, the goal for mitigation
of lost benzene emission reductions, based on the amended rule,
that occurred prior to the effective date of the alternative
compliance option shall not be changed.

      The plan for mitigating lost emissions will be evaluated
and assessed by the EPA Regional Office (including delegated
State and local agencies) in accordance with this guidance
document to determine their value as mitigation credit for
comparison to the mitigation goal.  Based on their evaluation,
the EPA will decide whether a waiver is warranted, and if so,
will determine the period and conditions for the waiver.
Owners/operators that do not meet the conditions of the waiver or
that fail to achieve compliance by the end of the waiver period
will be subject to a consent decree or other enforcement action.

2-4   Waiver Eligibility Criteria
      To be eligible for a waiver, an owner/operator of a source
must be able to demonstrate that it could not reasonably achieve
compliance by the compliance date (April 7, 1993).

      The source owner/operator must also plan to achieve full
compliance with Subpart FF as expeditiously as possible,
considering their chosen compliance path and the uncertainty
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concerning development of the site-specific risk alternative
compliance option.

      Lastly, the owner/operator of an affected facility must
sign an enforceable waiver agreement to achieve emission
reductions to compensate for the lost benzene emission reductions
resulting from delayed compliance with Subpart FF.  Emission
reductions should be achieved from sources located at the
affected facility.  To be counted or credited as mitigating
reductions, these mitigating environmental benefits must be
obtained during the time period between the old compliance date
(i.e., no earlier than March 7, 1992) and four years after the
new effective date (January 7, 1997).

2.5   Waiver Period vs. Length of Compliance Schedule
      The EPA is aware that there will be occasions in which a
facility will require a compliance schedule that exceeds the
maximum waiver period allowed.  For example, it may take an
owner/operator more than two years to implement a fully
integrated compliance approach and provide the required
mitigating environmental benefits.

      The Administrator will not deny a waiver application solely
because an applicant does not project full compliance by
January 7, 1995, i.e., the maximum allowable waiver period.  This
is a departure from past EPA policy where the Administrator would
not approve a waiver with a compliance schedule extending beyond
the waiver period.  For this NESHAP, the Administrator may allow
compliance schedules to exceed two years (January 7, 1995) if the
owner/operator has committed to a compliance strategy that
demonstrates compliance is being achieved expeditiously and
includes achieving the required mitigating environmental
benefits.  At the end of the two year waiver period, the facility
owner/operator could enter into a consent decree if compliance is
not achieved; this point is discussed further in Chapter 5.
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      In no event will a waiver of compliance with Subpart FF
extend beyond January 7, 1995 (two years beyond the effective
date of the final rule); nor will a waiver be granted for a
period longer than the time reasonably needed to install the
control ecniipment or pollution prevention process changes that
the source intends to construct or implement.  However/ the
waiver agreement may specify a time period to achieve mitigating
environmental benefits that lasts longer than the period needed
to comply with the benzene waste operations rule.  The
administrative aspects related to this situation are discussed in
Chapter 5.
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       3.0  ANALYSIS AND EVALUATION OF COMPLIANCE APPROACHES
3.1   Introduction
      As discussed in Section 2.2 (Goals of Waiver Policy), the
EPA believes it is important to mitigate the environmental
effects of delayed compliance with the benzene waste operations
NESHAP.  A source owner/operator requesting a waiver must propose
to achieve their mitigation goal (as discussed in Section 3.2 of
this guidance) by implementing mitigating actions.  Section 3.3
of the guidance document defines acceptable mitigating actions
and discusses how the mitigating environmental actions will be
evaluated by the EPA for comparison to the mitigation goal.

3.2   Determining a Source*s Waiver Mitigation Goal
      If a facility receives a waiver of compliance from
Subpart FF, there would be some quantity of "lost" benzene
emission reduction from waste operations during the period
between the original compliance date (March 7, 1992) and the end
of the waiver period.  This section of the guidance document
describes how to estimate the quantity of benzene that will be
emitted during this period, i.e., the lost benzene emission
reduction.

      As a surrogate to include the lost emission reduction
between the old and new compliance dates (March 1992 to April
1993), the lost benzene emission reduction during the waiver
period will be multiplied by 1.5 to yield the facility's waiver
mitigation goal.  The factor of 1.5 is used only as an
approximation of the benzene emission reduction lost between the
compliance dates.  Mitigation of the actual lost reduction
between the old and new compliance dates was also considered;
however, this approach would have introduced an inherent inequity
for facilities that request short-term waivers.  (For example,
each facility that requested a waiver would have had to mitigate,
based on the April 1993 compliance date, the full 13 months of
emissions, whether the waiver request was for 2 months or for 2
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years.)  Consequently/ the estimated benzene emission reduction
that is lost during the waiver period times 1.5 will serve as the
facility's waiver mitigation goal.  In the waiver application,
the facility must propose sufficient mitigating actions to equal
the mitigation goal.

      Figure 3-1 is a graphical representation of the lost
benzene emission reduction for an example facility, which is
represented by the dark shaded area.  The graph represents a
worst case because it shows no benzene emission reduction during
the stay of the rule.  Many facilities are expected to have
achieved some of the emission reduction required by the NESHAF
during this period.

      The "lost" reduction in the figure is based on compliance
with the rule as amended on January 7, 1993.  As previously
noted, an alternative compliance option based on site-specific
risk assessments may be proposed in early 1993.  Facilities that
apply for waivers but anticipate meeting an alternative
compliance option based on site-specific risk should submit
waiver applications that reflect a two-phase compliance path.
The first phase would outline how compliance will be achieved
with a site-specific risk assessment-based compliance option.  In
the waiver application, the applicant must demonstrate how, and
on what schedule, compliance under this option would be
expeditiously achieved.  This phase of the compliance path would
not have to show installation of control equipment necessary for
compliance with §§61.343 through 61.349 of Subpart FF, if that
control equipment would not be required under a compliance option
based on a site-specific risk assessment alternative compliance
option.

      The second phase of the waiver application's compliance
plan must document how the applicant will comply with §§61.343
through 61.349 of Subpart FF, as amended on January 7, 1993.
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This compliance path would then be implemented by the applicant
if an alternative compliance option based on site-specific risk
assessment is not promulgated.  For planning purposes, facilities
should assume that the EPA will take final action on the
alternative compliance option by August 1993.  An example of how
the lost benzene emission reduction would be calculated for the
alternative compliance option is given for Facility 2 in Section
4.3.

      The basic information needed to assess the baseline of
benzene emissions from waste operations includes identification
of the individual waste streams that contain benzene, how much
benzene they contain/ and how these waste streams are managed.
An upper bound on benzene emissions is provided by the benzene
quantity in the waste (Qb)/ calculated from the quantity of waste
and the benzene concentration.  The information on the individual
waste management units is used to estimate the fraction of the
benzene in the waste that is likely to be emitted (fe)-  Benzene
emissions are then estimated as the product of Qb x fe for each
waste stream.  More details on the estimates using the fraction
of benzene emitted are provided in Appendix A.  Background
information on the waste streams that each source should report
and common mistakes that have been made in reporting wastes
streams with benzene are given in Appendix B..

      Two approaches are provided for estimating the benzene
emission reductions lost during the waiver period.  One approach
is simplified and is based on the determination of total annual
benzene-in-waste (TAB - the.quantity of benzene in wastes that
either contain more than 10 percent water or that subsequently
become part of a mixture that contains more than 10 percent
water).  In this approach, the benzene emission reduction lost
(i.e., mass per unit time) during the waiver period is assumed to
equal the facility TAB plus any benzene quantities that are
excluded from the TAB calculation, such as averaging of process
turnaround wastes and ground water remediation wastes.  This
approach is environmentally conservative and would tend to
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overestimate the actual emissions.  The second approach is based
on estimates of benzene emissions from the various waste streams
for the different waste management units used at the facility.
Both approaches rely primarily on information that is gathered by
each facility for the 90-day report required under the rule.
The 90-day report identifies the waste streams that contain
benzene, waste quantity, benzene concentration, and the quantity
of benzene in the waste.  This information should be used for
either approach.

      The objective in presenting these two approaches to
estimating benzene emissions is to provide simple yet acceptable
means to calculate emissions (and lost emission reductions) from
sources regulated under the benzene waste operations NESHAP, and
the EPA urges applicants to use the methods specified in this
document.  Applicants may estimate emissions using other means;
however, they do so at the risk that the alternative method
selected may not be approved by the EPA.  Source testing is
generally discouraged as an emission estimating method for the
types of sources regulated under the benzene waste operations
NESHAP; this is because results of source tests generally reflect
emissions at a single point in time rather than over the long
term (i.e., annual average basis).  Adequate rationale for using
alternative methods for estimating emissions must be provided in
the application for a waiver.

      Mitigation goals and credits under the waiver policy must
be calculated based on a plan to achieve the emission levels
required by Subpart FF as amended on January 7, 1993.  This basis
remains the same for facility owner/operators choosing to wait
for the development of a site-specific risk alternative
compliance option.  If the alternative compliance option is
promulgated, owner/operators may modify their waiver
application/agreement to reduce the mitigation goal, based from
that date forward on lost benzene emission reductions under the
new compliance option.
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3.2.1.  Use of TAB to Estimate Lost Benzene Emissions
      The approach based on TAB is described using Table 3-1 to
illustrate the procedure.  The example in the table is for a
facility with a TAB of 27 Mg/yr.  Assume that the facility is
requesting a waiver of less than 2 years and expects the emission
controls needed for compliance with the rule to be in operation
at the end of the waiver period.  The lost benzene emission
reduction during the waiver period (1.75 years from April 1993 to
January 1995) can be calculated using the facility's TAB.  A
first approximation of the lost benzene emission reduction is 47
Mg (27 Mg/yr x 1.75 years).  Using the 1.5 multiplier mentioned
earlier (to account for emissions during the stay of the rule)
yields a mitigation goal of 71 Mg (47 x 1.5).

      This estimate assumes that all of the benzene in the TAB
potentially will be emitted and that the standard would control
100 percent of these emissions.  In addition/ this example
assumes no substantive emission reduction is obtained until all
of the controls are in place, which occurs at the end of the
waiver period.  (Some facilities are expected to achieve
significant emission reductions before the end of the waiver
period).

      Emissions from wastes that at all times contain 10 percent
or less water  (primary organic or "non-aqueous" wastes) should
also be included in the estimate of lost benzene emission
reductions.  If a facility manages non-aqueous wastes containing
10 percent or  less water in covered units (e.g., fixed roof
storage tanks), the emission factor in Appendix A can be used.
The resultant  benzene emissions from these covered units would
generally be insignificant compared to the facility's emissions
from aqueous wastes.  If the non-aqueous wastes are managed in
some other fashion, the emissions should be estimated using
methods applicable to that type of waste management operation.

      A similar approach can be applied to a phased compliance
schedule.  In  the example in Table 3-1, the desalter water will
                                3-6

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be controlled in 1.5 years, the product tank drawdown will be
controlled in 1.75 years, process wastewater will be controlled
in 1 year, and the slop oil tanks and sludges will be controlled
6 months into the waiver period.  Based on the TAB and the
compliance schedule, the lost benzene emission reduction during
the waiver period can be approximated as 38 Mg (16 x 1.5 +5 x
1.75 + 4.8 x 1), which yields a mitigation goal of 57 Mg (38 x
1.5).  The benzene in the slop oil and sludges has already been
included in the TAB shown in the table for the various water
streams; to include it in this calculation would be double
counting.  The wastewater streams may contain multiple phases,
including an oil phase that eventually ends up as slop
oil and a sludge phase that may be removed in waste treatment
processes. However, the TAB is determined at the point of
generation before the waste treatment processes are used to
separate these phases.

3.2.2  Estimates Based on Fraction Emitted
      This approach also uses the waste characterization data
provided in the 90-day report; however, emissions are estimated
based on the types of units that are used to manage the waste and
the emission control technologies serving these units.  First,
each facility must determine the quantity and benzene
concentration of all of their waste streams.  The facility must
also identify the types of waste management units that are used
for the treatment, storage, or disposal of the waste.  The types
of waste management units are then matched with the units listed
in Appendix A to obtain an estimate of the fraction of the
benzene in the waste that is emitted.  This procedure estimates
emissions by multiplying the waste quantity times the benzene
concentration times the fraction emitted.  If multiple units are
used in series, the emission estimate for a subsequent unit must
account for the benzene emitted in previous units.  This analysis
must also include emissions from wastes that contain 10 percent
or less water (e.g., organic wastes).
                                3-8

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      For the example in Table 3-1, assume that the wastes are
currently managed in the wastewater collection and treatment
system that includes the collection system (i.e., process drainsf
lift stations, and junction boxes) and treatment tanks  (i.e., an
open oil-water separator, equalization basin, and clarifier).
From Appendix A, the fraction emitted for the wastewater
treatment system (with an open oil-water separator) is  0.72.  In
addition, assume that, in order to comply with the rule, a steam
stripper will be used to treat the wastes from the desalter, tank
drawdown, and process wastewater with an overall emission control
efficiency of 99 percent.  Efficiencies for emission control
technologies range from 95 percent for simple add-on control
devices to 99 percent control by steam stripping.  The  annual
benzene emission reduction is estimated from the control
efficiency, fraction emitted, and benzene quantity for  the wastes
streams that are controlled:

(benzene quantity) x (fraction emitted) x (efficiency/100)
(16 + 5 + 4.8) Mg/yr x (0.72) x (0.99) = 18 Mg/yr.

If the waiver period is 1.75 years and compliance is achieved
primarily at the end of the waiver period, the lost benzene
emission reduction would be 31.5 Mg and the mitigation  goal would
be 47 Mg:

      Waiver period:  1.75 years x 18 Mg/yr = 31.5 Mg
      Mitigation goal:  31.5 Mg x 1.5 = 47 Mg

It is assumed that the organic wastes at this facility do not
make a significant contribution to this total and, therefore,
were not included in the overall estimate of lost benzene
emission reduction.

      For the phased compliance approach, assume that the
controls will be installed on the same example schedule described
earlier.  The lost benzene emission reduction is calculated for
each stream below:
                                3--9

-------
Desalter water:   (16 x 0.72 x 0.99) Mg/yr x 1.5 yr   -  17 Mg
Tank drawdown;    (5.0 x 0.72 x 0.99) Mg/yr x 1.75 yr -   6.2 Mg
Other wastewater; (4.8 x 0.72 x 0.99) Mg/yr x 1.0 yr  » 3.4 Mg
              Total lost benzene emission reduction   * 27 Mg
Mitigation goal; 27 Mg x 1.5 • 41 Mg.

This method of estimating the mitigation goal is more rigorous
than the previous method in which all the benzene in the facility
TAB is assumed to volatilize and no substantive emission
reduction is obtained (i.e, the entire TAB is emitted to the
atmosphere).  In this example, emissions are estimated based on
the types of units used to manage the waste and the efficiencies
of the emission control technologies serving these units.
Additional details on the fractions emitted for specific waste
management units are given in Appendix A.  Control efficiencies
are also given for different emission control approaches.  In
some cases, exact control efficiencies may not be known and may
be too burdensome to estimate.  For simplicity in estimating the
lost benzene emission reductions, an assumption of 100 percent
control (for only those waste streams that will be controlled)
will introduce very little error in the estimated benzene
emission reduction.  The small error introduced by this
assumption would require the facility to mitigate a slightly
higher quantity of benzene emissions.

3.3  Actions a Source May Take to Achieve Mitigation Credit
     Sources may implement any of a wide variety of actions for
the purpose of generating mitigation credits.  In general,
mitigation actions must be either:

     a.   not required by Federal, State or local regulations at
          the time agreement on the waiver conditions is reached,
          or
                               3-10

-------
     b.   beyond control levels required by Federal, State or
          local regulations at the time agreement on the waiver
          conditions is reached/ or

     c.   in advance of future regulatory or legislative
          requirements, but not after the compliance date of the
          new requirements.

     Permanent actions are preferred but temporary actions are
allowed; mitigating actions can cease when credits are equal to
debits (i.e., the mitigation goal).

     Some facilities, in order to resolve or forestall
enforcement action, may have committed to a consent order or
decree entered by the court.  As a condition of the decree, these
facilities may have agreed to install emission controls, or
otherwise reduce emissions.  If such emission reductions are
beyond what is required by Federal, State, or local regulations
at the time agreement on the waiver conditions is reached, credit
will be given for emission reductions resulting from installation
of controls in advance of the schedule in the consent decree.

     To illustrate the types and variety of rules affecting
benzene waste facilities, Appendix C lists the Federal air
environmental, regulations that affect petroleum refineries,
chemical plants, coke by-product plants, and waste treatment,
storage, and disposal facilities.  This list is not all
inclusive; it is provided solely to assist reviewers and
applicants.  The applicant remains responsible for certifying
that mitigating actions will be taken in advance of
Federal/State/local regulations, or exceed the requirements of
these regulations.

     Credit towards a facility's mitigation goal must be
generated by actions taken at the source.  Pooling and trading of
mitigating credits between facilities is not allowed, even if the
                               3-11

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facilities involved belong to the same owner/operator.  If
sufficient on-site mitigation opportunities are lacking, the
reviewing authority may, at their discretion, consider off-site
actions.  The applicant must demonstrate that the proposed off-
site emission reductions are real, quantifiable, enforceable, and
of direct benefit to the community surrounding/adjacent to the
facility.

3.3.1  Credits for Voluntary Actions Taken as a Result of
       Other Programs
     In general, reductions resulting from voluntary actions by
the facility and that are not required by a Federal, State, or
local regulation can be considered as mitigating actions; credit
for these actions will be granted beginning with the original
benzene waste operations NESHAP compliance date of March 1992.
Voluntary actions taken as a result of EPA or State initiatives
are allowable, but the actions must be documented and allowable
according to the specifics of this waiver guidance.

     a)   EPA's 33/50 Program:  Sources can obtain mitigating
          credit for actions taken under the EPA's 33/50 Toxics
          Reduction Program as long as the reductions meet other
          waiver criteria and can be documented according to the
          requirements established under this waiver guidance.
          The decision by sources to use their 33/50 actions as
          mitigating credit will remain a voluntary one, but the
          source owner/operator must make an enforceable
          commitment to achieve these reductions to qualify for
          mitigation under a Subpart FF compliance waiver.  The
          EPA will exert no pressure to require any 33/50 action
          to become an enforceable commitment.

     b)   CAA Early Reductions Program;  To the extent a source
          makes reductions in accordance with the Air Toxics
          Early Reduction's program authorized under subsection
          (i)(5) of Section 112 of the 1990 Clean Air Act
                               3-12

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     Amendments (CAAA), and to the extent those reductions
     meet the other requirements of the waiver guidance,
     credit will be given for the early reductions that are
     initiated after March 7, 1992, up to the date of
     proposal of the pertinent maximum achievable control
     technology (MACT) standard authorized under Section
     112(d) of the CAAA.  No credit will be given for early
     reductions after the pertinent MACT standard is
     proposed.

c)   Pollution Prevention Program;  Mitigating credit can
     also be generated through use of a pollution prevention
     measure.  For the purposes of this rule, the EPA is
     referring to those activities defined as source
     reduction measures in the Pollution Prevention Act.
     The types of activities that would be considered
     pollution prevention measures include technology
     modifications, process and procedure modifications,
     reformulation or redesign of products, and substitution
     of raw materials.  In each instance what defines them
     as source reductions is that a lesser quantity of
     pollution is produced prior to recycling, treatment, or
     control of emissions for a given quantity of product.
     A decrease in production alone does not qualify as
     pollution prevention; therefore, emission reductions
     resulting from shutdowns or downsizing of production or
     waste management units will not be allowed as credit
     for mitigating actions.

     Pollution prevention measures will be allowed to
     generate mitigation credit equal to the difference
     between the emissions allowed by the standard as
     applied to the previous process (after controls) and
     the emissions from the modified process.  This credit
     will be allowed over the period the modified process is
     in place and within the time frame specified for
     accumulation of waiver credits in this document.
                          3-13

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          Pollution prevention actions are the preferred means
          within the environmental management hierarchy for
          achieving mitigating benefits from the categories of
          actions listed below.  This is consistent with the
          national policy established by Congress under the
          Pollution Prevention Act of 1990.  The hierarchy
          established by the Act includes:  1) prevention or~
          reduction, 2) out-of-process recycling, 3) treatment,
          and 4) disposal or release.

3.3.2  Categories of Mitigating Actions
     There are several categories of actions that will be
considered in evaluating waiver applications.  Listed in order of
preference they are:
     1)   reductions in benzene air emissions from waste
          operations not controlled by the NESHAP,
     2)   reductions in benzene air emissions from other sources,
     3)   control of emissions of hazardous air pollutant (HAP),
          listed under §112 of CAA as amended in 1990, other than
          benzene,
     4)   control of non-HAP volatile organic compound (VOC)
          emissions, and
     5)   control of emissions of sulfur oxides (SOX) (maximum of
          3 projects).

     Further explanation and examples of these types of
mitigating actions are provided in Section 4.2 below ("Examples
of Mitigating Actions").  In addition, Section 4.3 discusses
examples of actions some sources could take to reduce air
pollutant emissions and the weighting factors applied to the
emission reductions achieved.

3.3.3    Restrictions on Allowable Mitigating Actions
     Benzene emission reductions from waste operations can be
considered as mitigating actions if the reductions would not
otherwise be obtained under Subpart FF.  For example, certain
wastes are exempt from the control requirements of the rule
                               3-14

-------
(e.g., wastes with a benzene concentration less than 10 ppmw).
If these wastes are treated for benzene removal or the units in
which they are managed are controlled for benzene emissions, the
resulting benzene emission reduction is an acceptable mitigating
action for the waiver application.  However, no credit will be
given for additional treatment for benzene removal for those
waste streams that are required by the NESHAP to be controlled.
For example, if a facility chooses to steam strip a wastewater
stream to some level below 10 ppmw, credit will not be given for
the incremental control below 10 ppmw.  The rationale for this
restriction is based on the fact that, in developing the rule and
its associated impacts, control or treatment of a large portion
of waste streams was assumed to result typically in benzene
concentrations in the waste well below 10 ppm (i.e., down to as
low as 0.5 ppm to meet the "toxicity characteristic" under the
Resource Conservation and Recovery Act (RCRA)).  A 99.9-percent
benzene removal was assumed for steam stripping in the original
determination of the impacts of .the rule; this was in large part
a result of the high volatility of benzene in wastewater.  The
EPA has concluded that, although current technology may allow
control of steam stripping effluent concentrations to just below
10 ppm, the incremental costs associated with this concomitant
control have not been shown to be significant.  Therefore, these
benefits are attributed to implementation of the rule itself.  In
addition, the incidental removal of pollutants other than benzene
(such as toluene, xylene, other volatiles) from an affected waste
stream that also occurs as a consequence of treating the waste
stream to remove benzene is not considered a mitigating action.
The control of these pollutants would be a direct consequence of
controls required by the benzene waste NESHAP, and as such, would
not represent additional emission reduction beyond that achieved
by the benzene waste operations NESHAP.

     Another example involves the use of 95- or 98-percent
control devices on vented vapors that are required to be
controlled under the rule.  The rule requires that these devices
achieve at least 95-percent control efficiency.  However, a
                               3-15

-------
facility cannot credit the incremental control achieved by using
a 98-percent control device instead of using a device designed to
achieve 95-percent control.  This restriction is based on the
fact that in many situations control devices designed and
operated to meet the requirements of the benzene waste rule would
in practice achieve greater than 95 percent benzene control;
therefore, this incremental emission control is directly
attributable to the benzene waste operations NESHAP.  An example
of control device requirements in the NESHAP that, when met,
assure that the device achieves greater than 95 percent reduction
are the flare requirements in Section 61.349(a)(2)(iii).  Flares
designed and operated to meet these conditions were found to
achieve at least a 98 percent destruction efficiency.  Enclosed
combustion devices are also expected to achieve greater than 98
percent control and were considered in the basis for the
standards.

     Mitigating actions affecting both benzene waste NESHAP-
subject waste streams and other waste streams would generate
mitigating credits only for emissions reductions from the non-
benzene waste NESHAP streams.  Emission reductions from wastes
subject to the NESHAP would have occurred through compliance with
the NESHAP.  With this approach, wastes not required to be
controlled under the NESHAP may be managed within the NESHAP
control system to obtain mitigation credit, which encourages
clustering (i.e., integrated approaches to treatment and
compliance).

3.3.4     Timing of Actions and Granting of Credit

A.   When can actions start generating credit toward mitigation
     goal?

     Sources may credit any allowable mitigating action
     implemented on March 7, 1992, or thereafter.  Mitigating
     credits begin to accumulate when the controls are in place

-------
     and are operational or the actions have been carried out and
     are thus in-effect.  In addition, for voluntary reductions
     of emissions that occur from participation in the EPA's
     33/50 program, sources may credit the resulting emission
     reductions that occur after March 7, 1992.

B.   When do actions stop generating credit toward mitigation
     goal?

     The waiver policy encourages owner/operators to generate
     credits toward the mitigation goal within the period of the
     waiver requested.  The EPA recognizes, however, that some
     comprehensive compliance programs may not generate
     sufficient mitigating credits within the proposed waiver
     period.  The EPA therefore will consider mitigating actions
     occurring up to January 7, 1997 (a maximum of two years
     following the end of the maximum allowed waiver period) for
     the purpose of generating mitigating credits only.

C.   Can credit be given for mitigating actions taken before a
     Federal/State/local requirement is established?

     There are two possible situations.  One occurs when there is
     an upcoming deadline for a regulatory or legislative
     requirement that will occur sometime after the compliance
     date for Subpart FF.  In this case, credit can be given, but
     only up until the compliance date of the regulatory or
     legislative requirement.

     The second situation occurs after the applicant and the EPA
     agree on the waiver conditions.  If a regulation is imposed
     after the agreement that would affect a specific mitigating
     action cited in the waiver agreement, the compliance date
     for the new regulation will not cancel any credit agreed
     upon between the EPA and the applicant, if the
     owner/operator had no prior knowledge of the rulemaking.
                               3-17

-------
     For facilities not participating in the Early Reductions
     Program, mitigation credit for early compliance with MACT
     standards will be allowed until the compliance date of the
     rule.  As noted earlier in 3.3.1(b), facilities
     participating in the Early Reductions Program would receive
     credit for early MACT compliance until the proposal of the
     MACT standard.

D.   If a facility is counting on promulgation of the alternative
     compliance option, how will this affect the mitigation
     credits required?

     Facilities must plan on achieving compliance with Subpart
     FF, even if they are waiting for the alternative compliance
     option.  Consequently, if a waiver is needed for compliance
     with Subpart FF, facilities must compensate for the benzene
     emissions lost due to delayed compliance with Subpart FF.
     Mitigation goals and credits under the waiver policy must be
     calculated based on a plan to comply with Subpart FF as
     amended on January 7, 1993, and not based on the alternative
     compliance option.

     If the alternative compliance option is promulgated, and a
     facility chooses this option as a route to compliance, the
     facility must compensate for lost benzene emission
     reductions until compliance with the alternative compliance
     option is achieved.  A facility may modify their waiver
     application/agreement to reduce the mitigation goal based on
     calculation of lost benzene emission reductions under a plan
     to comply with the alternative compliance option.  Lost
     benzene emission reductions that occur prior to the
     effective date of the alternative compliance option cannot
     be changed.
                               3-18

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3.3.5  Valuation of Mitigation Actions
     As discussed in Section 2.2 (Goals of Waiver Policy) of this
document, the EPA expects sources to achieve quantifiable
emissions reductions that mitigate the benzene emissions
reductions "lost" because of delayed compliance with the benzene
waste operations NESHAP.  Sources must demonstrate that the
mitigating value calculated in accordance with the criteria
provided below, meets or exceeds the mitigation goal calculated
in Section 3.2.

     a)   The value of mitigating actions is calculated on the
          basis of actual emissions reductions adjusted by a
          weighting factor, discussed in Section 3.3.6 below.

     b)   Actual emissions reductions are to be expressed as the
          mass of specific chemical constituents or group of
          constituents.  Emission reductions expressed as
          reductions in total waste stream quantity will not be
          accepted as part of the waiver application.

     c)   Mitigation credit will be given only for actual
          reductions of air pollutants.  Actual emission
          reductions must account not only for the emission
          reduction that occurs as a result of control actions
          taken at a specific process or waste management unit,
          but must also account for any increase in air emissions
          resulting from these actions at subsequent units as the
          pollutant is transferred from one unit to the next.
          For example, suppression type controls such as
          enclosures and covers can reduce emissions at the
          enclosed/covered unit and thereby increase emissions at
          the next downstream unit.  Moving emissions from one
          point to another will not be credited as an emission
          reduction.  In another example, a one (1) ton air
          pollutant mitigation credit is earned for reduction of
          benzene vapor in a gas stream through use of an
                               3-19

-------
          absorption device such as a wet scrubber.   This
          technology transfers the benzene from one  media, i.e.,
          the gas stream/  to another media, i.e.,  the wastewater
          stream.  If the  wastewater containing the  benzene from
          the gas stream is subsequently treated to  destroy all
          the benzene, then credit as a reduction in emissions
          can be given for the entire one (1)  ton.  However, if
          the benzene containing wastewater was subsequently
          stored in an open surface impoundment or air stripped
          following absorption then the mitigation credit should
          account for the  benzene emissions from this downstream
          processing.

     d)   Source owner/operators should seek mitigating air
          emission reductions in the order of  priority cited in
          Section 3.3.2.

     In structuring the priority system of mitigating actions, it
is not the EPA's intent to require treatment of benzene waste
streams in a highly (i.e., unreasonably) costly manner or to
require that all benzene containing streams be treated before
credit is allowed for actions involving non-benzene  emissions.
For example, conventional control technologies and work practices
applicable to waste management operation such  as equipment leak
monitoring (leak detection and repair) programs for  benzene
containing streams have been shown to be both  technically
feasible and economically reasonable; however, the more stringent
control alternative applicable to the same waste streams, use of
leakless valves, has not been determined to be either technically
feasible (in all cases) or economically reasonable.

3.3.6  Weighting of Emission Reductions Other than Benzene
     The weighting scheme used to calculate the value of
mitigating actions should not be considered a  definitive risk
comparison between benzene NESHAP emission reductions and
reductions of other sources of air pollution.   Nor is the
                               3-20

-------
mechanism outlined meant to produce a definitive statement that
the environmental risk resulting from delayed compliance is
absolutely mitigated.

     The following weighting scheme has been selected for use in
evaluating mitigating environmental benefits.  Any HAP, other
than benzene, listed pursuant to Section 112(b), Title III of the
Clean Air Act Amendments of 1990, will have a weighting factor of
1.1 (i.e., 1.1 Mg of other HAPs can be used to mitigate 1 Mg of
benzene).  For VOCs that are non-HAPs and sulfur oxides, the
weighting factor is 2.2 (i.e., 2.2 Mg of VOCs or sulfur oxides
can be used to mitigate 1 Mg of benzene).

3.3.7  Calculation of Waiver Credit
     An action's mitigating value is calculated as: (actual mass
of pollutant reduced) + (weighting factor for pollutant or group
of pollutants).

     More detailed examples are explained in Section 4.

3.3.8  Relationship of Waiver Actions to Future Regulatory
       Requirements
     The EPA approval of a waiver application and/or successful
implementation of mitigating actions does not necessarily
constitute compliance with other current or future regulation
requirements, and should not be construed as indicating EPA
recognition of such compliance.  The enforcement division will
ascertain compliance with respect to regulatory requirements.
                               3-21

-------
                 4.0  EXAMPLES OF WAIVER REQUESTS
     The purpose of this section of the guidance document is to
present hypothetical scenarios of some of the waiver pathways
that are available.  The examples illustrate the major approaches
that can be used to comply with the benzene waste NESHAP.  In
addition, a variety of mitigating actions are incorporated into
the examples.

4.1  What Are the Basic Compliance Approaches?
     The NESHAP provides a facility with several different
options to achieve compliance.  This flexibility permits the
owner or operator to select a compliance approach that is best
suited to a particular facility, considering the number and
quantity of waste streams to be controlled, the plant layout,
cost of control, and other current or future environmental
regulations.  A survey of the petroleum refining industry by the
American Petroleum Institute (API) indicated that different
plants planned to comply with the rule in different ways.
Although there are many possible combinations that can be used to
achieve compliance for any given source, the survey results
suggested that the compliance approaches could be divided into
three broad categories.  Note that a specific plant, especially
one of the larger facilities, could choose to implement a
combination of the three general approaches described below.

4.1.1  Pipe the Wastes to a Unit for Benzene Removal
     This approach involves collecting those waste streams that
must be controlled (e.g., wastewater with 10 ppm or more benzene)
and sending them to a steam, air, or fuel gas stripper to remove
the benzene from the water.  The wastewaters would generally be
sent to a central location for stripping through hardpiping to
avoid the loss of benzene in the wastewater collection system.
The benzene removed from the waste is condensed and recovered,
collected by carbon adsorption, or added to the fuel gas system
and eventually destroyed by combustion.
                                4-1

-------
     The advantage of this approach for some facilities is that
the existing wastewater collection and treatment system would not
have the controls that might otherwise be required if the streams
with 10 ppm or more benzene remained in the wastewater treatment
system.  Steam stripping is an attractive option for facilities
that can isolate the streams that must be controlled and can pipe
them to a central location (or multiple locations for a large
plant) for treatment.  This approach is less attractive for very
large plants, facilities with many different waste streams in
different locations that require treatment, and facilities that
plan to upgrade their wastewater collection and treatment system
for other reasons.

4.1.2  Control and Use the Existing Wastewater Treatment System
     This approach would require air emission controls for
individual drain systems, junction boxes, and wastewater
treatment tanks in the existing system.  Wastewater from the
various process units would be transported to wastewater
treatment as before; however, these units would be controlled for
air emissions.  In a system that collects oily wastewater, most
of the benzene would be recovered at the oil-water separator with
the organic layer that is removed.  Benzene that remains with the
water from the separator would likely be removed in controlled
units, such as a dissolved air flotation unit, or destroyed in an
enhanced biodegradation unit.

     Controlling the existing wastewater treatment system may be
an attractive option for plants that have relatively modern
facilities, segregated storm water sewers, or collection systems
or tanks that are already controlled.  For some of the older or
larger plants, the approach may not be attractive because
extensive repairs (or replacement) of parts of the system may be
required and extensive excavation or construction may be needed.
In addition, some plants may be planning to replace the existing
                                4-2

-------
system in the near future to avoid or to stop the contamination
of soil or groundwater by hazardous waste (e.g., water with over
0.5 ppm benzene).

4.1.3  Install a New, Hardpiped Segregated Wastewater System
     Several facilities are considering the installation of new
wastewater collection and treatment systems.  These systems would
have enclosed piping to transport the waste, which decreases the
potential for air emissions and leakage that may contaminate
groundwater.  As further protection, the piping may be
constructed above ground which provides for timely leak detection
and repair.  At some facilities, stormwater may be collected in a
separate system and managed in a manner different from that used
for the plant's wastewater.  The control of benzene emissions
could be accomplished as described above for existing systems,
with most of the benzene recovered at the oil-water separator,
some benzene removed and captured from subsequent treatment
tanks, and some destroyed by biodegradation.  With the enclosed
piping system, waste streams with high concentrations of benzene
could also be isolated for treatment in a steam stripper to
remove and recover the benzene.

     This approach is both time consuming and expensive for some
of the larger facilities because of the extensive construction
work that must be performed at an operating plant.  However, a
new wastewater collection system, perhaps with steam stripping
incorporated for certain wastes, may avoid the need for
corrective actions in the future under RCRA regulations.  This
represents an integrated compliance approach (also known as
clustering) that offers benefits to the environment other than
the control of benzene air emissions alone.

4.2  Examples of Mitigating Actions
     There are several different categories of actions that a
facility could perform to mitigate the lost benzene emission
reduction that results from extending the compliance date.  These
classes, in order of their priority as mitigating actions for
            :                   4-3

-------
lost benzene emission reductions/ include 1) reductions in
benzene emissions from waste operations not obtained by the
NESHAP, 2) reductions in benzene emissions from other sources/ 3)
control of HAP emissions other than benzene/ 4) control of non-
HAP VOC emissions/ and 5) control of SOX emissions (limited
situations only).  Additional details on the ground rules
associated with these mitigating actions are given in Section 3.

     All of the categories of mitigating actions are associated
with the control of air emissions.  Table 4-1 provides a summary
of typical air emission points and control techniques/
including sources associated with waste operations.  These types
of sources are candidates for mitigating actions for control of
air emissions/ including benzene emissions as well as emissions
of other pollutants.

     The first priority is to obtain additional benzene emission
reductions from waste operations/ if available.  Benzene emission
reductions from waste operations can be considered as mitigating
actions if the reductions would not otherwise be obtained by the
NESHAP.  For example/ certain wastes maybe exempt from the
control requirements of the rule  (e.g./ wastes with a benzene
concentration less than 10 ppmw).  If these wastes are treated
for benzene removal or the units  in which they are managed are
controlled for benzene emissions/ the resulting benzene emission
reduction is an acceptable mitigating action.  The removal of
other pollutants  (such as toluene/ xylene/ other volatiles) from
the wastes that are not required  to be controlled also can be
considered a mitigating action and could be credited as a result
of this same mitigating action.

     However, few mitigating opportunities are expected to be
available in this category because most benzene waste streams are
addressed by Subpart FF.  The types of waste streams that may be
available for additional emission control include 1) streams with
a low benzene concentration, and perhaps a small waste quantity,
                                4-4

-------
                                  TABLE 4-1.  SUMMRY OF AIR EMISSION POINTS AND CONTROLS
Baission point
Pn
res to determine emissions
                                                                                Emission control*
•  Tanks - fixed roof
•  Tanks - floating roof
   (1nternaI/externaI)

•  Tanks - op«n top
   (*.g., wastewater)

•  Wastewater collection
   (process drains,
   junction boxes, sewer
   lines)

•  Equipment leaks
   (pumps, valves, etc.)

•  Transfer operations
   (loading barges, tank
    trucks, drums)

•  Surface impoundments
•  Land treatment
•  Landfills
   Process vents
   (condensers, reactors,
    separation columns)

   Sludge dewatering
•  Fixation


*  Maintenance
   (equipment cleanout,
    draining)

•  Spills
API storage tank equations; need concentration,
throughput; tank design factorsif2
API storage tank equations; need tank design
parameters; concentration and throughput^ 2,3

Documented emission models; naad site-
specific  information on contents, operation*

Guidance, emission factors available^
EPA emission factors; knowledge of process
fluid; equipment count and leak survey2,6

EPA emission equations!^
Documented emission models; need site-
specific information on contents, operation*

Documented emission models; need site-
specific information on contents, operation*

Documented emission models; naad site-
specific information on contents, operation*

Measure concentration and flow rate?
Emission tests conducted8>9
                             EPA emission factors available:
                             refinements under development^

                             Adapt emission models;  need quantity,
                             concentrat i on*
                             Bnission models available;  need quantity,
                             concentration,  frequency*
                                            Vent to control device;
                                            retrofit internal floating
                                            roof

                                            Secondary seals; gaskets;
                                            enclose and vent to control

                                            Cover and vent to contra I;
                                            pretreat to remove benzene

                                            Enclose; vent to control;
                                            water seals; treat at point
                                            of generation (steam strip)
                                            Leak less equipment; leak
                                            detection and repair

                                            Submerged fill; vapor
                                            balance; vent to control
                                            Cover;  vent to control;
                                            pretreat (steam strip)

                                            Pretreat to remove benzene
                                            Pretreat to remove benzene;
                                            enclose,  vent to control

                                            Vent to  control  device
                                           Enclose,  vent to control;
                                           pretreat  to remove benzene

                                           Enclose,  vent to control;
                                           pretreat  to remove benzene

                                           Containment;  enclosure;
                                           Pretreat  to remove volatil«s
                                                   Containment and cleanup;
                                                   improved housekeeping
                                                  4-5

-------
for which control is not cost effective, and 2) streams with
recoverable organics, large waste quantities, or other features
that make control cost effective (such as a waste stream from a

desalter with a concentration of less than 10 ppmw) .


     Benzene emission reductions obtained from sources other than
waste operations at a facility represent the second priority and

can be used as mitigating actions.  The mitigating action can
include controlling an emission source that would otherwise be
uncontrolled, or the action may obtain additional control of a
source that is already controlled.  Many facilities may find that
few opportunities are available in this mitigation category
because emissions from these sources are addressed by other
NESHAP, New Source Performance Standards (NSPS), and Control
Technology Guidelines (CTG).  Some possibilities are listed
below:

1.   Control storage tanks not covered by a NESHAP, NSPS, or CTG,
     or control beyond the requirements of the applicable rule.

     •    Vent a fixed roof tank to a control device or install
          an internal floating roof,

     •    Vent tanks that have a floating roof to a control
          device (not likely to be cost effective),

     •    Control tanks that contain less than pure benzene that
          are not affected by Subpart Y, and

     •    Control tanks that fall below the tank size and vapor
          pressure cutoffs of the NSPS for volatile organic
          liquids.

2.   Control emissions from equipment leaks not covered by a
     NESHAP, NSPS, or CTG, or control beyond the requirements of
     the applicable rule  (for example, control to the level that
     resulted from the regulatory negotiations for the hazardous
     organic NESHAP).

3.   Control process vents, which are generally not covered by
     current rules (because the rules were developed under the
     assumption that most vents are already controlled).

4.   Control emissions from transfer operations, such as ships,
     barges, and trucks that are not controlled, or control
     beyond current requirements.


                                4-6

-------
     The next priority for emission reductions is the control of
emission sources that do not emit benzene, or the application of
additional control for these sources can be considered as
mitigating actions.  The hierarchy for control of air pollutants
other than benzene is to control other HAPs, followed by the
control of non-HAP VOCs.  For example, the control of product
storage tanks or barge loading may result in the reduction of
emissions of other HAPs or VOCs even if benzene is not present.
Another example is a source, not covered by the Benzene Waste
Operations NESHAP/ that is controlled by a condenser or carbon
adsorber with an efficiency of 95 percent.  If the source
installs a vapor incinerator to replace the existing control, the
incremental reduction from 95- to 98-percent control can be
considered a mitigating action.  Additional emission reductions
in benzene, HAPs, and VOCs achieved by the vapor incinerator
would be considered as mitigation credits.  All benefits accrue
for each mitigation action taken.

4.3  Example Facilities
     This section presents several examples of baseline emissions
and proposed mitigating actions for facilities that may request a
waiver.  An attempt has been made to illustrate some of the
different approaches that can be used for compliance and the
types of mitigating actions that could be considered in the
waiver application process.  The examples indicate the new
compliance date of April 7, 1993.  Actual compliance schedules
would have considerably more detail, e.g., more interim milestone
dates, than shown in the following examples.  These examples are
abbreviated for illustrative purposes and are refinery oriented,
but the same basic concepts would apply to chemical plants and
coke by-product plants.

     In these illustrations, the following weighting scheme has
been used.  Any HAP other than benzene listed pursuant to
subsection (b) of Section 112, Title III of the Clean Air Act
Amendments of 1990, will have a weighting factor of 1.1 (i.e.,
1.1 Mg of other HAP can be used to mitigate 1 Mg of benzene).
                                4-7

-------
For non-HAP VOCs and SOx/ the weighting factor is 2.2 (i.e., 2,2
Mg of VOC or SOx are used to mitigate 1 Mg of benzene).  Although

not explicitly stated in each example, the facility has followed

the mitigation hierarchies shown in Sections 3.2.2 and 4.2.


     Facility 1

Compliance Approach;  This facility is a petroleum refinery that
plans to comply with the NESHAP by steam stripping the major
wastewater streams that contain 10 ppm benzene, using carbon
adsorbers on slop oil tanks, and pretreating sludges for benzene
removal.  Oil-water separators will be installed at the desalter
and product tanks to recover hydrocarbons from the water before
it is stripped.  Wastes from maintenance activities and process
unit turnarounds sum to less than 2.0 Mg/yr benzene and will be
exempted under the small benzene quantity exemption.

Compliance Schedule:

     •  Oil-water separators controlled by carbon adsorbers will
        be installed in the process units to separate and recover
        any separate hydrocarbon phase from the desalter water
        and drawdown from various product storage tanks.
        Controlled conveyances will be used to transport the
        wastes to the oil-water separator.  The oil or product
        will be returned directly to the process and the water
        layer will be piped to a steam stripper.  The controlled
        separators will be installed by the old compliance date
        (3/92) and will reduce benzene emissions from the
        wastewater'system by 10 Mg/yr.

     •  Process wastewater that contains over 10 ppmw benzene,
        primarily desalter water and tank drawdown from the oil-
        water separators described above, will be piped to a
        steam stripper for treatment.  The steam stripper will
        become operational by 10/93 and will reduce benzene
        emissions by 10 Mg/yr.

     •  Controls will be installed on slop oil tanks by 4/93 and
        will achieve a benzene emission reduction of 1 Mg/yr.

     •  Solvent extraction will be used to remove benzene from '
        sludges generated by the oil-water separators by 4/93.
        This will result in an actual benzene emission reduction
        of 1 Mg/yr (after consideration of extractor emissions).

     • "Overall, these controls will reduce benzene emissions
        from waste operations from 26 Mg/yr to 4 Mg/yr.

     Figure 4-1 presents a graphical illustration of the lost
benzene emission reductions in relation to Facility 1's
compliance schedule.
                                4-8

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Estimate "lost" benzene emission reduction and mitigation goal;

     A description of the procedure used to estimate the
mitigation goal is given in Section 3.2.

     •  Lost emission reduction is 5 Mg:
        - 10 Mg/yr x 0.5 yr  = 5.0 Mg

     This estimate is based on emissions from the steam stripper
(4/93 to 10/93); other activities to comply with the NESHAP, such
as the oil-water separator and slop oil tank controls, occur
before the new compliance date and thus do not enter into the
lost emission reduction calculation.

     •  Mitigation goal is 7.5 Mg:
        - 5 Mg x 1.5 » 7.5 Mg.

Proposed mitigating actions;

     1.  This facility is located in a State that has established
regulations to control benzene and other volatile organic
compound emissions; consequently, there are limited opportunities
for other emission reductions (tanks, leaks, and process units
are generally controlled).  As a mitigating action, the facility
proposes to steam strip additional process wastewaters with
benzene concentrations that range from 0.5 to less than 10 ppmw
(i.e., these streams do not have to be controlled under the
benzene waste NESHAP).  This proposal would result in an
additional benzene air emission reduction of 2 Mg/yr; however,
the reductions would not be obtained until the steam stripper is
operational in 10/93.  This mitigating action will be continued
past the end of the waiver period.

     2.  The action proposed in Item 1 will also result in air
emission reductions of toluene (0.62 Mg/yr), xylene (0.46 Mg/yr)
and miscellaneous VOCs (0.37 Mg/yr).

     3.  The additional benzene emission reduction through the
waiver period and continued for 2 years past the maximum waiver
period is 6.5 Mg:
          2 Mg/yr x 1.25 yr + 2 Mg/yr x 2
          (10/93 - 1/95)     (1/95 - 1/97)
yr = 6.5 Mg
Reductions of other pollutants for the same period would be 2 Mg
for toluene, 1.5 Mg for xylene, and 1.2 Mg for miscellaneous
VOCs.

Evaluation;

     The mitigating activities include a reduction of 6.5 Mg for
benzene emissions, 2.0 Mg of toluene, 1.5 Mg of xylene, and
1.2 Mg of miscellaneous VOCs.  The equivalent reduction for HAPs
(toluene and xylene at 1.1 to 1) is 3.2 Mg, and the equivalent


                               4-10

-------
reduction for other VOCs is 0.5 Mg (at 2.2 to 1).  The proposed
mitigation results in an equivalent reduction of 10 Mg (6.5 + 3.2
+ 0.5), which exceeds the mitigation goal of 7.5 Mg.

     Figure 4-2 shows the actual mitigating reductions achieved
by Facility 1 based on the schedule of proposed actions.

     Facility 2

Compliance Approach;  This facility is a petroleum refinery that
plans to modernize their process sewer system.  Process liquids
previously discharged to below grade will be managed in enclosed
systems above grade or in a double-contained system below grade.
The facility has submitted a compliance plan with two phases.
The first phase is based on compliance with an alternative
compliance option for site-specific risk.  If the alternative
compliance option for site-specific risk is promulgated in August
1993, the facility plans to comply with the alternative
compliance option in October 1993.  If the alternative compliance
option is not promulgated, the facility will implement the second
phase of the compliance plan and comply with the approach they
have outlined based on the requirements in the rule as amended on
January 1, 1993 by April 1994.

Compliance Schedule /rule as amended on January 7, 1993):

     •  Controls will be installed on slop oil tanks by 4/93 and
        will achieve a benzene air emission reduction of 2 Mg/yr.

     •  Modifications to the wastewater collection and treatment
        system will be completed by 10/93.  This will achieve a
        benzene air emission reduction of 29 Mg/yr.

     •  Tank drawdown will be piped to the enclosed wastewater
        treatment system by 4/94 and will achieve a benzene air
        emission reduction of 4 Mg/yr.

     •  After controls are implemented, benzene air emissions
        from waste operations will be reduced from 37 Mg/yr to 2
        Mg/yr.

     Figure 4-3 presents a graphical representation of the lost
benzene emission reductions in relation to Facility 2's
compliance schedule for the rule as amended January 7, 1993.


Estimate "lost" benzene emission reduction and mitigation goal;

     •  Lost emission reduction is 18.5 Mg:
        - 29 Mg/yr x 0.5 yr = 14.5 Mg (wastewater system)
        - 4 Mg/yr x 1 yr = 4 Mg (tank drawdown)

     •  Mitigation goal is 28 Mg:
        - 18.5 Mg x 1.5 = 28 Mg.


                               4-11

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                          4-13

-------
Compliance Schedule falternative compliance option):

     •  For planning purposes, the alternative compliance option
        is assumed to be promulgated in August 1993.

     •  A preliminary analysis by the company indicated that the
        site-specific risk target in the alternative compliance
        option could be met by reducing benzene emissions from
        waste operations to 6 Mg/yr or less.

     •  The company proposes to implement controls on slop oil
        tanks by 4/93 and to complete modifications to the
        wastewater collection and treatment system by 10/93 (as
        previously described).  The alternative standard would be
        met in 10/93 by reducing benzene emissions from 37 Mg/yr
        to 6 Mg/yr.

     •  Tank drawdown would continue to be managed in the
        existing uncontrolled wastewater collection system and
        would not be controlled as described in the compliance
        approach for the amended rule.  However/ the combined
        wastes from tank drawdown would be piped from the
        existing collection system to the new enclosed treatment
        system.

     Figure 4-4 presents a graphical representation of the lost
benzene emission reductions for the alternative compliance
approach projected by Facility 2.

Estimate "lost* benzene emission reduction and mitigation goal:

     •  If the alternative compliance option is promulgated and
        the facility achieves compliance as projected, the
        mitigation goal is different from that given above for
        compliance with the original rule.  The lost benzene
        emission reduction in this case is based on a shorter
        waiver period from the new compliance date (April 1993)
        to the time that compliance with the alternative
        compliance option is achieved (October 1993).

     •  During the waiver period (4/93 to 10/93), the lost
        reduction is 16.5 Mg:

        - 29 Mg/yr x 0.5 = 14.5 Mg (wastewater system)
        -  4 Mg/yr x 0.5 = 2 Mg (tank drawdown)

     •  The mitigation goal under the alternative compliance
        option is 25 Mg:

        - 16.5 Mg x 1.5 = 25 Mg.

Proposed mitigating actions;

     1.  Condensate from the  flare system will be controlled to
obtain a benzene air emission reduction of 1 Mg/yr by 7/93.  This

                               4-14             -

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    4-15

-------
waste has a benzene concentration of less than 10 ppm and is not
required to be controlled.

     2.  Secondary seals will be installed on floating roof tanks
by 1/94 to reduce benzene air emissions by 3 Mg/yr.  The
frequency of leak detection and repair (LDAR) for equipment leaks
will be increased by 4/93 to obtain an annual benzene emission
reduction of 1.0 Mg/yr.  Controls will be installed on marine
loading/unloading operations by 7/93 to obtain a benzene air
emission reduction 2 Mg/yr.

     3.  The quantity of benzene emissions voluntarily reduced in
Items 1 and 2 is 23 Mg up to January 1997:

     Condensate:       1 Mg/yr x 3.5 yr - 3.5 Mg
     Secondary seals:  3 Mg/yr x 3 yr = 9 Mg
     LDAR:             1 Mg/yr x 3.75 yr = 3.8 Mg
     Marine loading:   2 Mg/yr x 3.5 yr = 7 Mg

     4.  The controls described in Item 2 will also reduce air
emissions of other air pollutants, listed below in terms of the
emission reduction obtained during the period ending on
January 1, 1997:

                     Reductions of other pollutants (Mq)
  Source              TolueneXylene     VOCs*

  Secondary seals       2.0       1.0       1.6
  LDAR                  0.5       0.5       0.2
  Marine loading        1.0       0.5       1.0

     Total              3.5       2.0       2.8

  * The individual organics were not identified; these compounds
    include primarily C2 to Cg hydrocarbons.

Evaluation?

     The mitigation proposed for this facility includes air
emission reductions of 23 Mg of benzene, 3.5 Mg of toluene, 2.0
Mg of xylene, and 2.8 Mg of VOCs.  The value of these reductions
in terms of benzene is 29 Mg (the HAPs, toluene, xylene at 1.1 to
1, other VOCs at 2.2 to 1).  The mitigation goal was 28 Mg based
on compliance with the rule as amended January 7, 1993, and 25 Mg
based on compliance with the alternative compliance option;
consequently, the mitigation credits exceed the mitigation goals.
Figure 4-5 shows the actual mitigating reductions achieved by
Facility 2 based on the schedule of proposed actions.

     Facility 3

Compliance Approach:  This facility is a petroleum refinery that
plans to control their existing wastewater collection and
treatment system.  Traps will be installed on process drains,


                               4-16

-------
junction boxes will be covered (and vented to a control device if
necessary), oil-water separators will be controlled, and other
tanks will be covered and controlled up to the enhanced
biodegradation unit.  In addition, slop oil tanks and sludge
handling processes will be controlled for benzene air emissions.
The facility also plans to implement a pollution prevention
technique by changing their desalting process.  A light oil that
contains benzene is currently added to the desalter water to
improve the separation of oil and water; however, this light oil
contains benzene that increases the benzene concentration in the
water.  This light oil will be replaced by a fuel oil that
contains no significant quantity of benzene, which will reduce
the amount of benzene removed with the desalter water.  The
facility will be in compliance with the NESHAP by 4/94.

Compliance Schedule;

     • Oil-water separators will be installed at the tank farm by
       7/93 to recover oil and other product from the water
       before it is discharged to the sewer.  These separators
       will be controlled by carbon adsorbers and will reduce
       benzene emissions from the wastewater system by 8 Mg/yr.

     • The pollution prevention process change from light oil to
       a benzene-free oil will be completed by 4/94 and will
       reduce benzene emissions from the wastewater by 15 Mg/yr.

     • Modifications to the wastewater collection and treatment
       system will be completed by 4/94.  This will achieve a
       benzene emission reduction of 20 Mg/yr.

     • Controls will be installed on slop oil tanks and sludge
       management units by 4/93 and will achieve a benzene
       emission reduction of 2 Mg/yr.

     Figure 4-6 illustrates the lost benzene emission reductions
in relation to Facility 3's compliance schedule.


Estimate  "lost" benzene emission reduction and mitigation goal:

     • Lost emission reduction is 37 Mg:
       -  8 Mg/yr x  0.25 yr * 2 Mg (tank drawdown)
       -  15 Mg/yr x 1 yr = 15 Mg (desalter water)
       -  20 Mg/yr x 1 yr = 20 Mg (wastewater system)

       (Since slop oil tank and sludge unit emissions are
       controlled before 4/93, these emissions are not included
       in the lost benzene calculation.)
     • Mitigation goal is 56 Mg:
       - 37 Mg x 1.5 • 56 Mg.
                               4-18

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Proposed mitigating actions;

     1.  Secondary seals will be installed on floating roof tanks
and fixed-roof tanks will be vented to a control device by 4/93
to reduce benzene emissions by 5 Mg/yr.  The frequency of leak
detection and repair will be increased by 4/93 to obtain an
annual benzene emission reduction of 3 Mg/yr.  Controls will be
installed on marine loading/unloading operations by 7/93 to
obtain a benzene emission reduction 4 Mg/yr.  The additional
benzene air emission reduction up to January 1997 is 44 Mg (19 Mg
for secondary seals, 11 Mg for leak detection, and 14 Mg for
marine loading).

     2.  The controls described in Item 1 will also reduce air
emissions of other air pollutants, listed below in terms of the
emission reduction obtained up to January 1997:

                     Reductions of other pollutants (Ma)
  Source             Toluene    Xvlene     Other orqanics*

  Secondary seals       4.0       1.0            2.0
  Leaks                 0.5       0.5            0.6
  Marine loading        3.0       1.0            2.8

     Total              7.5       2.5            5.4

  * The individual organics were not identified; these compounds
    include primarily C2 to Cg hydrocarbons.

Evaluation;

    The proposed mitigation includes 44 Mg of benzene, 10 Mg of
    other HAPs valued at 9.1 Mg, and 5.4 Mg of other VOCs valued
    at 2.5 Mg.  The mitigation credits of 56 Mg equals the goal
    of 56 Mg.

    Figure 4-7 shows the accumulation of mitigating reductions
for Facility 3 based on the schedule of proposed actions.


  Facility 4

Compliance Approach;  This facility is a large, old petroleum
refinery that plans to modernize their process sewer system;

  • Process liquids previously discharged to below grade will be
    managed in enclosed systems above grade or in a double-
    contained system below grade.

  • Wastewater treatment tanks, such as the oil-water separator
    and dissolved air flotation unit, will be equipped with
    emission control devices.  Tanks that manage the recovered
    slop oil will also be controlled.
                               4-20

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• Tank water draws will be controlled by hardpip:_r.g to the
wastewater treatment system.

Compliance Schedule;

• Controls will be installed on slop oil tanks by 4/93 and wiJ
achieve a benzene emission reduction of 2 Mg/yr.

• The new wastewater treatment system will be installed by 1/9
and will reduce benzene emissions by 44 Mg/yr (compliance
will be achieved one year after the end of the maximum waive
period).

Figure 4-8 illustrates the lost benzene emission reductions
based on Facility 4's compliance schedule.