[Federal Register Volume 61, Number 166 (Monday, August 26, 1996)]
[Proposed Rules]
[Pages 43698-43718]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-21280]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[AD-FRL-5558-3]
RIN 2060-AC19


National Emission Standards for Hazardous Air Pollutants for 
Source Categories: Organic Hazardous Air Pollutants From the Synthetic 
Organic Chemical Manufacturing Industry and Other Processes Subject to 
the Negotiated Regulation for Equipment Leaks; Proposed Rule 
Clarifications

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule: Amendments.

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SUMMARY: On April 22, 1994 and June 6, 1994, the EPA issued the 
National Emission Standards for Hazardous Air Pollutants for Source 
Categories: Organic Hazardous Air Pollutants from the Synthetic Organic 
Chemical Manufacturing Industry and Other Processes Subject to the 
Negotiated Regulation for Equipment Leaks. This rule is commonly known 
as the Hazardous Organic NESHAP or the HON. In June 1994, petitions for 
review of the April 1994 rule were filed in the U.S. Court of Appeals 
for the District of Columbia Circuit. The petitioners raised over 75 
technical issues and concerns with drafting clarity of the rule. 
Today's action proposes correcting amendments to the rule to address 
the petitioners' issues.
    Today's action proposes new definitions that apply to wastewater 
and wastewater treatment and revised control and compliance provisions 
for wastewater. A new compliance date of April 22, 1999, is being 
proposed for process wastewater, heat exchange systems, in-process 
equipment subject to the provisions of Sec. 63.149, and maintenance 
wastewater. The proposed changes to these provisions are sufficiently 
far reaching and complex to render those provisions effectively a new 
rule. The EPA is also proposing a separate compliance date for 
wastewater streams affected by the omission of nitrobenzene from the 
list of compounds subject to the wastewater provisions. The proposed 
revisions to the other provisions to the rule are corrections and 
clarifications to ensure the rule is implemented as intended. Today's 
amendments would also provide some additional compliance options that 
would reduce the burden associated with the recordkeeping and reporting 
requirements of the rule.
    The proposed amendments to the rule will not change the basic 
control requirements of the rule or the level of health protection it 
provides. The rule requires new and existing major sources to control 
emissions of hazardous air pollutants to the level reflecting 
application of the maximum achievable control technology.

DATES: Comments. Comments must be received on or before September 25, 
1996 unless a hearing is requested by September 5, 1996. If a hearing 
is requested, written comments must be received by October 10, 1996.
    Public Hearing. Anyone requesting a public hearing must contact the 
EPA no later than September 5, 1996. If a hearing is held, it will take 
place on September 10, 1996, beginning at 10:00 a.m.

ADDRESSES: Comments. Comments should be submitted (in duplicate, if 
possible) to: Air and Radiation Docket and Information Center (6102), 
Attention Docket Number A-90-19 (see docket section below), Room M-
1500, U.S. Environmental Protection Agency, 401 M Street, SW, 
Washington, D.C. 20460. The EPA requests that a separate copy also be 
sent to the contact person listed below.
    Public Hearing. If a public hearing is held, it will be held at the 
EPA's Office of Administration Auditorium, Research Triangle Park, 
North Carolina. Persons interested in attending the hearing or wishing 
to present oral testimony should notify Ms. JoLynn Collins, Waste and 
Chemical Processes Group, U.S. Environmental Protection Agency, 
Research Triangle Park, N.C. 27711, telephone (919) 541-5671.
    Docket. Dockets No. A-90-19 through A-90-23, containing the 
supporting information for the original NESHAP and this action, are 
available for public inspection and copying between 8:00 a.m. and 5:30 
p.m., Monday through Friday, at the EPA's Air and Radiation Docket and 
Information Center, Waterside Mall, Room M-1500, first floor, 401 M 
Street SW, Washington, DC 20460, or by calling (202) 260-7548 or 260-
7549. A reasonable fee may be charged for copying. Comments on the 
proposed changes to the NESHAP may also be submitted electronically by 
sending electronic mail (e-mail) to: [email protected].

FOR FURTHER INFORMATION CONTACT: For general questions, contact Dr. 
Janet S. Meyer, Coatings and Consumer Products Group, at (919) 541-5254 
or Mary Tom Kissell, Waste and Chemical Processes Group, at (919) 541-
4516. For technical questions on wastewater provisions, contact Elaine 
Manning, Waste and Chemical Processes Group, telephone number (919) 
541-5499. The mailing address for the contacts is Emission Standards 
Division (MD-13), U.S. Environmental Protection Agency, Research 
Triangle Park, North Carolina 27711.

SUPPLEMENTARY INFORMATION:

I. Regulated Entities and Background Information

A. Regulated Entities

    The regulated category and entities affected by this action 
include:

------------------------------------------------------------------------
             Category                  Examples of regulated entities   
------------------------------------------------------------------------
Industry..........................  Synthetic organic chemical          
                                     manufacturing industry (SOCMI)     
                                     units, e.g., producers of benzene, 
                                     toluene, or any other chemical     
                                     listed in Table 1 of 40 CFR part   
                                     63, subpart F.                     
                                    Styrene-butadiene rubber producers. 
                                    Polybutadiene rubber producers.     
                                    Producers of Captafol;    
                                     Captan; Chlorothalonil;  
                                     Dacthal; and TordonTM acid.        
                                    Producers of Hypalon;     
                                     Oxybisphenoxarsine/1,3-diisocyanate
                                     (OBPA); Polycarbonates;  
                                     Polysulfide rubber; Chlorinated    
                                     paraffins; and Symmetrical         
                                     tetrachloropyridine.               
                                    Pharmaceutical producers.           

[[Page 43699]]

                                                                        
                                    Producers of Methylmethacrylate-    
                                     butadiene-styrene resins (MBS);    
                                     Butadiene-furfural cotrimer;       
                                     Methylmethacrylate-acrylonitrile-  
                                     butadiene-styrene (MABS) resins;   
                                     and Ethylidene norbornene.         
------------------------------------------------------------------------



    This table is not intended to be exhaustive but, rather, provides a 
guide for readers regarding entities likely to be interested in the 
revisions to the regulation affected by this action. Entities 
potentially regulated by the HON are those which produce as primary 
intended products any of the chemicals listed in table 1 of 40 CFR part 
63, subpart F and are located at facilities that are major sources as 
defined in section 112 of the Clean Air Act (CA). Processes subject to 
the negotiated regulation for equipment leaks (i.e., 40 CFR part 63, 
subpart I) are also potentially affected by this action. Processes 
subject to 40 CFR part 63, subpart I are producers of any of the 
products listed in 40 CFR part 63, subpart I that are located at 
facilities that are major sources as defined by section 112 of the CA. 
To determine whether your facility is regulated by this action, you 
should carefully examine all of the applicability criteria in 40 CFR 
63.100 and 40 CFR 63.190. If you have questions regarding the 
applicability of this action to a particular entity, consult the person 
listed in the preceding FOR FURTHER INFORMATION CONTACT section.

B. Copies of Regulatory Text

    The proposed regulatory text is not included in this Federal 
Register action because of the length and complexity of the amendments 
to the rule. The proposed changes to the rule are discussed fully in 
this preamble. The proposed amendments to the rule are available in 
Docket A-90-19 or by request from the Air and Radiation Docket and 
Information Center (see ADDRESSES) or the EPA contact person listed in 
the preceding FOR FURTHER INFORMATION CONTACT section. The proposed 
rule amendments may also be obtained over the Internet at http://
ttnwww.rtpnc.epa.gov or from the EPA's Technology Transfer Network 
(TTN). The TTN is a network of electronic bulletin boards developed and 
operated by the Office of Air Quality Planning and Standards. The 
service is free, except for the cost of a phone call. Dial (919) 541-
5742 for up to a 14,400 bits per second modem. Select TTN Bulletin 
Board: Clean Air Act Amendments and select menu item Recently Signed 
Rules. If more information on TTN is needed, contact the systems 
operator at (919) 541-5384.

C. Electronic Submission of Comments

    Comments on the proposed changes to the NESHAP may also be 
submitted electronically by sending electronic mail (e-mail) to: a-and-
[email protected]. Electronic comments must be submitted as an 
ASCII file avoiding the use of special characters and any form of 
encryption. Comments will also be accepted on diskette in WordPerfect 
5.1 or ASCII file format. All comments in electronic form must be 
identified by the docket number A-90-19. No Confidential Business 
Information (CBI) should be submitted through e-mail. Electronic 
comments may be filed online at many Federal Depository Libraries.

D. Background on Rule

    On April 22, 1994 (59 FR 19402), and June 6, 1994 (59 FR 29196), 
the EPA published in the Federal Register the NESHAP for the SOCMI, and 
for several other processes subject to the equipment leaks portion of 
the rule. These regulations were promulgated as subparts F, G, H, and I 
in 40 CFR part 63, and are commonly referred to as the hazardous 
organic NESHAP, or the HON. Since the April 22, 1994 notice, there have 
been several amendments to clarify various aspects of the rule. Readers 
should see the following Federal Register notices for more information: 
September 20, 1994 (59 FR 48175); October 24, 1994 (59 FR 53359); 
October 28, 1994 (59 FR 54131); January 27, 1995 (60 FR 5321); April 
10, 1995 (60 FR 18020); April 10, 1995 (60 FR 18026); December 12, 1995 
(60 FR 63624); February 29, 1996 (61 FR 7716); and June 20, 1996 (61 FR 
31435).
    In June 1994, the Chemical Manufacturers Association and Dow 
Chemical Company filed petitions for review of the promulgated rule in 
the U.S. Court of Appeals for the District of Columbia Circuit, 
Chemical Manufacturers Association v. EPA, 94-1463 and 94-1464 (D.C. 
Cir.) and Dow Chemical Company v. EPA, 94-1465 (D.C. Cir). The 
petitioners raised over 75 technical issues on the rule's structure and 
applicability. Issues were raised regarding details of the technical 
requirements, drafting clarity, and structural errors in the drafting 
of certain sections of the rule. Today's proposed revisions address all 
of the issues raised by CMA and Dow on the April 1994 rule.
    With today's action, EPA is proposing clarifying and correcting 
amendments to subparts F, G, H, and I of part 63. Following review and 
consideration of comments received on today's proposed revisions in 
accordance with a settlement agreement reached with CMA and Dow, EPA 
will take final action on the proposed amendments by December 31, 1996. 
As of the date of signature of this proposal, the section 113(g) notice 
process was not yet complete, and, therefore, the settlement was not 
final. However, EPA believes it is important to publish the proposed 
rule in accordance with the schedule provided in the draft settlement 
agreement because of the pendency of the compliance date. When a 
settlement becomes final, it will govern the date of signature of the 
final rule. As discussed in section III.B, sources subject to the rule 
would be expected to be in compliance with the amended provisions for 
heat exchange systems, maintenance wastewater, in-process equipment 
subject to Sec. 63.149, and process wastewater by April 22, 1999. 
Equipment subject to the other provisions of the rule would be expected 
to be in compliance by April 22, 1997, unless a compliance extension is 
granted. The EPA anticipates finalizing some portions of the proposed 
rule earlier than December 31, 1996. For example, the proposal would 
eliminate the need for filing some implementation plans that would 
otherwise be due December 31, 1996, and would allow the filing of 
requests for compliance extensions up to 4 months before the April 1997 
compliance date. The EPA will attempt to take final action on these 
provisions as soon as possible after the close of the comment period in 
order to give sources as much lead time as possible.

II. Overview of Changes to Rule

    With today's proposed action, EPA is proposing clarifying and 
correcting amendments to subparts F, G, H, and I of 40 CFR part 63. 
These proposed amendments include an extension of the compliance date 
to April 22, 1999 for process wastewater, heat exchange systems, 
maintenance wastewater, and in-process equipment subject to the 
provisions of Sec. 63.149. These sections of the rule would be 
extensively revised by

[[Page 43700]]

today's proposal. The proposed revisions are intended to remove any 
ambiguity and clearly convey EPA's intent, to make the rule easier to 
read and implement, and to increase flexibility for the source.
    The proposed amendments would also set a separate compliance date 
for wastewater streams affected by the omission of nitrobenzene from 
table 9 of subpart G. A three year compliance date is being proposed 
for process wastewater streams that are subject to control requirements 
due to the presence of nitrobenzene due to an error in the April 22, 
1994 rule. The compliance date for other emission points remains April 
22, 1997.
    The proposed revisions to the wastewater sections of the rule have 
been redrafted to improve organizational structure and drafting 
clarity. One significant clarification would be to the definition of 
``wastewater'' which would be revised to incorporate the concept that 
only when water is discarded from a process is it subject to the HON 
wastewater provisions. Additional changes would be made to the 
wastewater provisions to: (1) ensure that streams traveling from one 
piece of process equipment to another would be handled appropriately to 
avoid emissions to the environment, and (2) ensure that the changes in 
the wastewater definitions would not permit sources to dilute their 
waste streams prior to the point the streams are considered wastewater, 
thus avoiding control requirements. If a HON source owner or operator 
wished to ship waste off-site for treatment, the owner or operator may 
only ship to a facility that has certified that it will treat the waste 
to the standard required by the HON.
    In contrast to the significant redrafting of the wastewater 
provisions, minor edits are proposed for other sections of the rule. In 
addition to removing ambiguity and increasing flexibility for the 
source, some revisions would reduce the reporting and recordkeeping 
burden for sources. The reporting and recordkeeping revisions would 
include changes which: reduce the number of copies of reports that must 
be submitted to EPA and the States; provide for alternative, less 
frequent recordkeeping of monitoring data where sources show no 
violations for prolonged stretches of time; and remove the requirement 
for most sources to file an implementation plan.

III. Compliance Date Changes and Other General Changes

A. Applicability of Rule

1. Designation of the Source
    In today's amendments, EPA is proposing revisions to Sec. 63.100, 
paragraphs (e) and (f) to clarify which equipment is included within 
the scope of the source regulated by this rule. These revisions are 
being proposed because the drafting and structure of paragraphs (e) and 
(f) in Sec. 63.100 have caused confusion and raised concerns as to 
whether other equipment or activities not listed are included in the 
source. The proposed revisions to these paragraphs are intended to 
improve rule clarity.
    The present wording of paragraph (e) of Sec. 63.100 incorporates, 
inter alia ``wastewater and associated treatment residuals'' in the 
source. This text does not state explicitly whether waste management 
units, heat exchange systems, or maintenance wastewater are included in 
the source. The present designation of the source also does not include 
control devices or recovery devices used to comply with this rule. Some 
industry representatives have expressed concern that these types of 
equipment could be considered subject to section 112(g) of the Act 
because the equipment is not part of a source subject to a section 
112(d) standard. To address this concern, the EPA is proposing to 
revise this paragraph by listing the specific categories of equipment 
and types of wastewater included in the source and by adding control 
and recovery devices to the items designated to be included in the 
source. The EPA is also proposing to revise paragraph (f) of 
Sec. 63.100 to reverse the drafting structure to state that the listed 
items are included in the source, but are not subject to the control 
requirements of the rule. Based on discussions with industry, EPA has 
found that reversing the structure would make it more understandable to 
the regulated community and would reduce the chance of incorrect 
interpretation.
2. Definition of Chemical Manufacturing Process Unit (cmpu)
    The EPA is proposing amendments to clarify the definition of cmpu 
and the definition of unit operation. The proposed revisions consist of 
clarifying that a cmpu consists of two or more unit operations and 
correcting the definition of unit operation to refer to the defined 
term ``distillation units'' instead of distillation columns. These 
proposed changes are expected to clarify the determination of 
applicability for facilities with integrated operations.
3. Applicability of Rule to Storage Vessels Located in a Tank Farm or 
Marine Terminal
    The EPA is proposing amendments to clarify the applicability of the 
rule to storage vessels located in tank farms and marine tank farms. 
The proposed amendments being added as Sec. 63.100(g)(3) would 
explicitly specify the procedures to be followed to assign the storage 
vessels to a process and then to determine the applicability of the 
rule. Due to an oversight, the provisions currently in Sec. 63.100(g) 
of subpart F do not include instructions regarding allocation of tanks 
in remote locations.
    Following issuance of the 1994 rule, EPA received inquiries 
regarding the applicability of the rule to storage vessels that are 
physically remote from the cmpu, but are located at the major source 
and connected to the cmpu by piping. Some of the inquiries raised 
questions regarding the distinction between storage vessels used for 
product storage and vessels used more for purposes of facilitating 
product distribution. Other inquiries concerned applicability of the 
rule where a dedicated product (or raw material) storage tank was 
located in the tank farm. Following a review of the rule language and 
the underlying analyses for the rule, EPA concluded that the record on 
this point was ambiguous and that the rule should be amended to clarify 
these issues. The proposed revisions to Sec. 63.100(g) are based on the 
concepts presently used in the rule for assignment of equipment that is 
shared among several cmpus and on a basic assumption used in developing 
the rule that, which is typically a cmpu, includes raw material and 
product storage vessels.
    The proposed provisions assign a storage vessel to a cmpu based on 
three decision rules. First, a storage vessel in a tank farm is 
considered to be part of a cmpu only if the cmpu does not have another 
intervening, storage vessel for product (or raw material). Where there 
is an intervening storage vessel, the boundary of the cmpu would end at 
that intervening storage vessel (and any associated transfer operations 
and other equipment) and would exclude the tank farm storage vessel. 
Second, if two or more cmpus (of those using the tank farm storage 
vessel) lack a co-located storage vessel, then the storage vessel at 
the tank farm would be assigned to a cmpu, according to the concepts of 
predominant use specified in Sec. 63.100(g)(2). Third, if only one cmpu 
(of those that use the remote storage

[[Page 43701]]

vessel) lacks a co-located product (or raw material) storage vessel, 
then the remote storage vessel would be assigned to that cmpu.
    The EPA expects that this assignment procedure will result in 
assignment of storage vessels in a manner consistent with normal 
management of facility operations. Specifically, it is expected that 
storage vessels that are an integral part of operation of a cmpu 
subject to the HON will be regulated under the HON and that storage 
vessels that are used to facilitate product distribution will be 
regulated as part of the organic liquids distribution source category 
and not under the HON.
4. Determination of Applicability of the Rule to Equipment Shared Among 
Integrated Operations
    Today's proposed amendments include clarifying changes to the 
equipment assignment procedures specified in Sec. 63.100 (g), (h), and 
(i) for storage vessels, transfer racks, and distillation units. Since 
the HON was issued in April 1994, EPA has received inquiries regarding 
the correct interpretation of the text in these paragraphs. Based on 
these inquiries and discussions with industry representatives, EPA has 
concluded that the questions and concerns are due to minor wording 
differences in paragraphs (g) and (h) and the absence of an explicit 
statement that paragraph (i) specifies the assignment procedures for 
shared distillation columns.
    Today's proposed amendments would make the wording and structure of 
these paragraphs parallel. Specifically, the proposed revisions would 
make the wording of paragraphs (g)(1) and (h)(1) parallel to the 
wording in paragraphs (g)(2) and (h)(2), respectively. The proposed new 
paragraphs would add provisions to paragraph (i) that address the 
assignment of dedicated distillation units and would clarify that the 
assignment procedure is for distillation units shared among several 
processes. The proposed revisions also clarify the wording of the 
requirement to reassess the assignment of the equipment whenever there 
is a change in the use of the equipment.
5. Revision to Table 2 of Subpart F List of Regulated Hazardous Organic 
Air Pollutants (HAP's)
    The EPA has received numerous requests for clarification of the 
definition of ``Polycyclic organic matter'' (POM) in table 2 of subpart 
F. The nature of these requests indicates that there is confusion 
regarding the scope of the definition. To eliminate this confusion, EPA 
is proposing to revise table 2 of subpart F to list the specific 
compounds that are to be regulated as POM in the HON. The specific 
compounds being listed are consistent with the historical working 
definition of POM, which emphasizes emissions from incomplete 
combustion and pyrolysis processes (49 FR 31680). This change is 
expected to improve rule clarity.

B. Compliance Dates

1. Compliance Date Extension for Wastewater Provisions
    With respect to compliance dates, the final rule promulgated on 
April 22, 1994, provided that existing sources must be in compliance 
with the requirements of subparts F and G no later than April 22, 1997, 
unless an extension is granted in accordance with Sec. 63.151(a)(6) of 
subpart G or Sec. 63.6(i) of subpart A.
    Today's proposal would change the compliance date provisions 
applicable to HON sources in two significant respects. These changes 
are included in Sec. 63.100(k)(2) of today's proposed rule. First, 
Sec. 63.100(k)(2)(ii) would set a new compliance date of April 22, 
1999, for heat exchange systems, maintenance wastewater, in-process 
equipment subject to Sec. 63.149, and process wastewater. Second, 
Sec. 63.100(k)(2)(ii)(A) would set a new compliance date that is three 
years from the date of final publication for process wastewater streams 
and in-process equipment subject to Sec. 63.149 that are subject to 
control requirements due to the contribution of nitrobenzene to the 
annual average concentration of Table 9 compounds.
    The new compliance date for heat exchange systems, maintenance 
wastewater, in-process equipment subject to Sec. 63.149, and process 
wastewater is being proposed because the changes to these provisions 
applicable to HON sources are sufficiently far reaching and complex to 
render those provisions effectively a new rule warranting a new 
compliance date. In contrast, the changes to other portions of the 
April 22, 1994, rule are less extensive, are more in the nature of 
corrections and clarifications, and EPA does not believe they 
jeopardize sources' ability to meet the April 1997 compliance date.
    Section 112(i)(3) of the Act provides that existing sources are to 
be in compliance with applicable emission standards ``as expeditiously 
as practicable, but in no event later than 3 years after the effective 
date of such standard.'' The April 22, 1994, final rule specified a 
compliance date applicable to wastewater streams and heat exchange 
systems that was three years from the issuance of that rule. Section 
112(d)(6) provides authority for the Administrator to revise the 
emission standards issued under section 112 ``no less often than every 
8 years.'' EPA believes that the authority to revise the standards 
inherently includes the authority to set new compliance dates for 
revised rules. Any other approach would require existing sources to 
come into compliance with potentially extensive revisions immediately, 
just as if they were new sources. Obviously, Congress provided EPA 
discretion to set a compliance date for existing sources of up to three 
years in order to provide time for retrofitting of controls where 
necessary. Thus, due to the extensive nature of the revisions to the 
provisions applicable to heat exchange systems and wastewater streams, 
the creation of requirements for in-process equipment subject to 
Sec. 63.149, and the proximity to the April 1997 compliance date in the 
original rule, EPA is setting a new compliance date for those 
provisions.
    EPA believes that two years from the otherwise applicable 
compliance date will be sufficient for all sources to come into 
compliance with the new wastewater and in-process equipment provisions. 
However, should any source be unable to meet that compliance date 
because of the need to install controls that cannot be installed by 
that date, such source may request an extension of up to one year in 
accordance with Sec. 63.151(a)(6).
    The new three year compliance date in Sec. 63.100(k)(2)(ii)(A) for 
process wastewater streams and in-process equipment subject to 
Sec. 63.149 that are subject to control requirements due to the 
presence of nitrobenzene, is being proposed because of an error in the 
April 22, 1994, rule. Nitrobenzene is a HAP included on the section 
112(b) list. However, due to an oversight, it was not included on table 
9 (which lists HAPs subject to the wastewater provisions) in the April 
22, 1994, rule. Thus, there was confusion as to whether or not the 
presence of nitrobenzene in wastewater streams should be a factor in 
determining whether such streams were Group 1 or Group 2. This error 
was corrected in the December 12, 1995, correction notice (60 FR 63624 
(December 12, 1995)). However, due to the extensive changes to the 
wastewater provisions and the uncertainty caused by the initial 
omission of nitrobenzene from table 9, EPA is proposing to set a new 
compliance date for wastewater streams affected by the error.
    EPA seeks comment on its proposal to set new compliance dates in 
Sec. 63.100,

[[Page 43702]]

paragraphs (k)(2)(ii) and (k)(2)(ii)(A), and in particular seeks 
comment on the appropriateness of the particular dates proposed.
2. Timing of Compliance Extension Requests
    The April 22, 1994, rule requires that requests for compliance 
extensions be submitted one year prior to the otherwise applicable 
compliance date. The EPA is proposing to revise this requirement, which 
is in Sec. 63.151(a)(6)(i), to allow submittal of requests up to 120 
days prior to the compliance date. The EPA is also proposing to add a 
new paragraph (iv) to Sec. 63.151(a)(6) that would allow requests 
during the last 120 days before the compliance date if the need arose 
during that 120 days and if the need was due to circumstances beyond 
the reasonable control of the owner or operator. Submission of a 
compliance extension request would not stay the applicability of the 
rule to the applicant source during the pendency of the request.
    The EPA is proposing these revisions in recognition that review of 
most requests for compliance extensions can be completed within 4 
months and it is unlikely that it would require 12 months to complete 
review of the request. The EPA is also proposing to allow submittal of 
extension requests up to the compliance date in recognition that 
unforeseen difficulties, such as construction or operational 
difficulties, can arise in the last moments of compliance planning. The 
proposed provisions in Sec. 63.151(a)(6)(iv) are also considered 
necessary in the case of this rule because it is unlikely that these 
proposed revisions will be final more than 4 months prior to the April 
22, 1997, compliance date for certain control requirements. Any changes 
in the wording or requirements of the final rule could affect 
compliance planning for a source. Therefore, EPA believes that it is 
necessary to provide some opportunity for applications for compliance 
extension requests after the date that is 4 months prior to the 
compliance date.
3. Clarification of Compliance Periods
    The proposed revisions to subpart F also would add a new paragraph 
(k)(9) to Sec. 63.100, and a new paragraph (g) to Sec. 63.162 to 
clarify that when the rule specifies a period of time for completion of 
required tasks (e.g., weekly, monthly, quarterly, annual), this refers 
to standard calendar periods unless it is specified otherwise in the 
section or paragraph that imposes the requirement. The current rule 
does not specify this, and this text is being added to the rule to 
remove any potential for ambiguity. The new Sec. 63.100(k)(9) and 
Sec. 63.162(g) also provide that time periods may be changed by mutual 
agreement between the owner or operator and the Administrator, as 
provided in subpart A of this part. Finally, this new set of provisions 
also provides that if the rule requires completion of a task during 
each of multiple successive periods, an owner or operator may perform 
the required task at any time during the specified period, provided the 
task is conducted at a reasonable interval after completion of the 
previous task. When the rule was originally drafted it was assumed that 
this could be done, but an oversight in drafting language specifying 
this was omitted from the rule.

C. Heat Exchanger Provisions

    In today's amendments, the EPA is proposing new requirements for 
monitoring heat exchange systems for leaks of process fluids into 
cooling water. The proposed Sec. 63.104 would replace the existing 
provisions in Sec. 63.104 of subpart F. The proposed revisions are 
being made to address issues with the existing provisions related to 
the availability of monitoring methods with sufficient analytical 
sensitivity, lack of flexibility in some of the requirements, and the 
burden associated with the monitoring requirements. The major revisions 
to this section of the rule and the reasons for the changes are 
described below.
1. Conditions Exempted From Monitoring Requirements
    The existing provisions of Sec. 63.104 exempt two categories of 
heat exchange systems from the monitoring requirements. The first 
exempt category is heat exchange systems operated with a greater 
pressure on the cooling water side. These systems were exempted because 
any leakage would be into the process fluid, not into the cooling 
water, so it is not necessary to monitor the cooling water for the 
presence of process fluids. The second exempted category is once-
through heat exchange systems operating with a National Pollutant 
Discharge Elimination System (NPDES) permit allowable discharge limit 
of less than 1 ppm. These two categories were exempted because the 
provisions of Sec. 63.104 would impose a redundant requirement. The 
proposed revisions to Sec. 63.104 would extend this exemption to three 
additional cases. First, facilities with NPDES permits that require 
monitoring of a parameter or condition that would detect a leak of 
process fluids and requires the owner or operator to report and correct 
leaks when the parameter or condition exceeds the normal range. For 
facilities with such NPDES permit the requirements in Sec. 63.104 would 
be redundant with the NPDES permit requirement. Second, systems where 
there is an intervening cooling fluid (containing less than 5% by 
weight of the applicable HAP's) between the process and the cooling 
water would be exempted. In these systems, the monitoring requirements 
of Sec. 63.104 are unnecessary because leaks of process fluids would be 
detected in intervening process equipment before there could be a leak 
into the cooling water. The third exempt category is systems used to 
cool process fluids that contain less than 5% by weight HAP's. This 
last category of heat exchange systems is being added because it is 
consistent with the intent that provisions only require monitoring when 
HAP's are present in concentrations greater than 5% by weight.
2. Hazardous Air Pollutants Subject to Monitoring Requirements
    The April 22, 1994, rule requires owners or operators of 
recirculating heat exchange systems to monitor for organic HAP's listed 
in table 2 of subpart F, except for four water-reactive HAP's. Today's 
proposed amendments would reduce the number of organic HAP's subject to 
the monitoring requirement for these recirculating systems. The revised 
list of organic HAP's subject this requirement is provided in proposed 
table 4 of subpart F. There are no proposed changes to the organic 
HAP's subject to the monitoring requirement (found in table 9 of 
subpart G) for once-through cooling systems.
    Since the April 22, 1994, rule was issued, EPA has received 
inquiries regarding the basis for the requirement to monitor for table 
2 compounds in cooling water of recirculating heat exchange systems. 
Some industry representatives have questioned the inclusion of 
compounds that are not on table 9 of subpart G and have argued that 
cooling towers are ineffective at air stripping relatively nonvolatile 
compounds (i.e., compounds not in table 9) listed in table 2 of subpart 
F. In response to these questions, EPA modeled the potential air 
emissions of each table 2 compound from a process cooling tower. This 
analysis indicated that there are about 23 compounds listed in table 2 
of subpart F that have no, or very insignificant, potential for 
emissions. Examples of organic HAP compounds that were found to have 
little potential for volatilization in a cooling tower are ethylene 
glycol and acrylamide. Based on this modeling

[[Page 43703]]

analysis, EPA concluded that it would be appropriate to apply 
monitoring requirements to some compounds on table 2 of subpart F as 
well as to compounds listed on table 9 of subpart G. This conclusion is 
based on finding that there are a number of compounds which have an 
insignificant potential for emission from typical wastewater collection 
and conveyance systems but which can have fairly substantial losses 
when sent through a process cooling tower. Proposed table 4 lists the 
compounds modelled to have significant emission potential when sent 
through a process cooling tower. Also, in order to limit monitoring to 
only those compounds calculated to have significant emission potential 
and to eliminate unnecessary burden, proposed table 4 lists specific 
glycol ethers instead of the family of compounds. This was done because 
different glycol ethers have significantly different physical 
properties.
3. Added Flexibility to Monitoring Requirements
    The rule currently requires monitoring of cooling water using any 
EPA approved method in 40 CFR part 136 as long as the method can 
measure concentrations of the compound as low as 1 ppm. Since issuance 
of the rule in April 1994, EPA has received information that the 
methods in 40 CFR part 136 are not available for some HAP's and that 
the additional requirement for measurement sensitivity further reduces 
the number of available methods. To correct these implementation 
problems, EPA is proposing the following revisions to Sec. 63.104.
    The proposed Sec. 63.104 includes provisions that would allow 
monitoring of a surrogate indicator of a heat exchanger leak in lieu of 
monitoring for specific organic HAP's in the cooling water. This new 
option is being proposed because of analytical limitations and costs of 
measuring some of the organic HAP's regulated by this provision and 
because, in some cases, the intent of this section can be met by using 
a surrogate indicator. Proposed Sec. 63.104 also includes provisions 
that would allow monitoring of a surrogate indicator such as ion 
specific electrode monitoring, pH, or other physical properties of the 
cooling water or process operations. The EPA expects that this option 
would be useful in cases where there are no EPA approved methods for 
any compounds in the process or where there are easily measured process 
parameters that provide a reliable indication of heat exchanger leaks. 
Under this new alternative, an owner or operator would prepare and 
implement a monitoring plan that would specify the parameters that 
would be monitored and the criteria which, if exceeded, would 
constitute a leak. The owner or operator would have to update the 
monitoring plan anytime a substantial leak is detected by methods other 
than those described in the plan and identify the methods in the plan 
that did not detect the leak. These provisions were developed based on 
consideration of existing programs and work practices at some SOCMI 
facilities for detecting leaks of process fluids into cooling water. It 
is expected that this alternative will be less burdensome than the 
existing requirements and may allow use of existing procedures to meet 
this requirement.
    The EPA is also proposing to revise the minimum sensitivity 
requirement for analytical methods from 1 ppm to 10 ppm. This change is 
being proposed to increase the number of methods available for use in 
the organic HAP monitoring alternative and to reduce the cost of this 
monitoring. The EPA selected 10 ppm as the minimum sensitivity for the 
method based on consideration of the detection limits for the EPA 600 
series methods.
    The EPA also realizes that even with this increase in the minimum 
sensitivity to 10 ppm, there will be a few compounds for which there is 
no approved quantitative analysis method. Because of this problem, the 
existing provisions of Sec. 63.104(b) were revised to specify that the 
monitoring of organic HAP's may be to monitor a subset (one or more) of 
the organic HAP's in the cooling water. The EPA expects that this 
change in the wording of the organic HAP monitoring alternative will 
allow monitoring of the compound (or compounds) that can be measured 
and will remove the appearance that the monitoring has to be capable of 
detecting every HAP at the minimum sensitivity.
4. Miscellaneous Clarifications to Sec. 63.104
    Today's proposed Sec. 63.104 would allow sampling across the 
cooling tower, at the entrance and exit of each heat exchange system, 
or any combination of heat exchangers (e.g., across a cmpu or at a 
plant site). The April 1994 rule specified that the sampling was to be 
across the cooling tower. The EPA is proposing to revise this 
requirement because of concerns that have been expressed that the 
present rule is inflexible and requires monitoring at a location that 
is less cost effective. The April 1994 rule specified monitoring across 
the cooling tower because of public comments received on the proposed 
rule. Today's proposed revisions differ from the original proposed 
language in that there is more flexibility in the selection of sampling 
locations and the terminology has been clarified in that the rule now 
specifically defines the convention for entrance and exit of systems.
    Today's proposed revisions to Sec. 63.104 include clarification and 
correction of the existing language that defines a leak. The wording of 
the existing provision in Sec. 63.104(b)(1)(v) has resulted in 
inquiries regarding the proper interpretation. Proposed 
Sec. 63.104(b)(6) specifies the type of statistical test as well as the 
significance level in defining a leak. The EPA requests comment on 
whether the revised language will appropriately identify and minimize 
the number of false positive indications of a leak.
    The proposed Sec. 63.104 would also revise the delay of repair 
provisions to allow delay until the next shutdown if a shutdown is 
planned within 2 months of determination that delay of repair is 
necessary. The proposed revisions to Sec. 63.104 would also allow delay 
of repair up to a maximum of 120 days if the necessary parts or 
personnel are not available. The April 1994 rule only allows delay of 
repair when it can be demonstrated that immediate shutdown for repair 
would create more emissions than the emissions that would result from 
delaying repair of the leaking heat exchanger until the next shutdown. 
The proposed revisions to the delay of repair provisions of the rule 
are being made to make these provisions workable and to minimize debate 
over modeling of emissions from heat exchanger systems.

D. Control Alternatives

1. Routing Emissions to a Process
    The EPA proposes to add provisions to the rule to allow routing of 
emissions to a process or fuel gas system as a means of compliance 
where appropriate. Currently, subparts G and H are not amenable to use 
of recycling to a process or fuel gas system as a means of compliance 
with the control requirements. These revisions would allow use of this 
compliance approach without defining the process or fuel gas system as 
a control device and imposing, in turn, control device monitoring and 
recordkeeping requirements. This change is being made to encourage use 
of pollution prevention control approaches and to reduce the monitoring 
and recordkeeping burden of the rule.
    The proposed amendments consist of: (1) revisions to the 
definitions for

[[Page 43704]]

process vent and vapor balancing system and addition of definitions for 
fuel gas and fuel gas system in subpart F; (2) amendments to the 
storage vessels and transfer operations provisions in subpart G; and 
(3) addition of a definition of ``route to a process'' and inclusion of 
this option in the list of control requirements in subpart H. The 
definitions for fuel gas and fuel gas system are based on the 
definitions recently promulgated in subpart VV, part 60 and in subpart 
CC, part 63 (Refinery NESHAP). The proposed definitions have been 
reworded slightly to remove the refinery-specific references and to 
refer to combustion devices more generally instead of listing specific 
types of combustors.
    The proposed amendments to subpart G to allow recycling to a 
process for storage vessels and transfer operations require that the 
recycled material be used or consumed in the same manner as a material 
that fulfills the same function in the process, be transformed into a 
material that is not an organic hazardous air pollutant, or be 
recovered or incorporated into a product. These restrictions are placed 
on this option to avoid the potential for sham claims of recycling. The 
proposed provisions for storage vessels also include provisions to 
allow limited by-pass of the process or fuel gas system during periods 
of maintenance or repair of the process or fuel gas system. These 
provisions are necessary because these storage vessels would not 
necessarily be emptied during these maintenance periods and emissions 
would continue from the vessel. Since more emissions would result if 
the rule were to require emptying and degassing of storage vessels 
during these periods than if the vessels were allowed to vent to the 
atmosphere, provisions are being added to Sec. 63.119 to allow by-pass 
of the fuel gas system or process during these periods. These 
provisions specify the conditions that must be met during these by-pass 
periods to minimize emissions. Similar provisions are not being 
proposed for transfer operations because it is not believed to be 
necessary. Loading operations can normally be postponed until the 
process or fuel gas system is operational again.
    The proposed amendments to subpart H consist of addition of a 
definition of ``route to a process'' and changes to the control options 
for pumps, compressors, etc. The definition of ``route to a process'' 
incorporates the key concepts used in subpart G provisions for storage 
vessels and transfer operations. No provisions have been included in 
the proposed amendments to subpart H to allow by-pass during periods of 
maintenance or repair of the process or fuel gas system. The EPA does 
not believe that parallel provisions are needed for equipment leaks.
2. Lower Bound Concentration Performance Standard
    The EPA is proposing to add an alternative performance standard 
limit of 20 parts per million by volume concentration limit for 
noncombustion control devices used to comply with the process vent, 
storage vessel, and wastewater provisions in subpart G and the 
equipment leak provisions of subpart H. This option would be in 
addition to the present performance standard of 98 or 95 percent 
removal of total VOC or HAP, respectively, in these sections of the 
rule. This lower bound concentration standard is being added to those 
sections of the rule where EPA believes there would not normally be 
significant amounts of dilution air and any attempts to circumvent 
could be detected. The EPA is proposing this change to the rule to 
provide a lower bound concentration level for use in cost effective 
design of control devices and recovery devices such as carbon adsorbers 
and condensers.
    This lower bound concentration performance standard is proposed to 
be added to the rule to reflect actual performance of these control 
devices and to make the rule's requirements consistent with the 
underlying cost and emission analyses for this rule. Most recovery 
devices (e.g., condensers, adsorbers, etc.) are designed to achieve a 
specific outlet concentration for a maximum loading scenario for a 
stream with specific characteristics. The specific outlet concentration 
of a given system is a function of the equilibrium and kinetic limits 
for the technology and the characteristics of the gas stream and the 
cost of the system. For any given design, these devices will typically 
reduce emissions to the same concentration level over a relatively wide 
range of inlet concentrations. Thus, when the inlet concentration is 
substantially below the design maximum loading conditions (and begins 
to approach the residual level in the outlet stream) the recovery 
device efficiency will decrease. When this occurs the outlet 
concentration is the same or lower than the outlet concentration during 
maximum loading conditions. The cost and emission control estimates 
used in development of this rule were based on maximum design loading 
conditions and did not reflect operations over the full range of 
potential operating conditions for the SOCMI industry. Therefore, it is 
necessary to specify a lower bound concentration performance level in 
addition to the removal efficiency in the rule to ensure that this rule 
is implemented as intended. Where EPA considered the use of this 
alternative to be appropriate, the proposed amendments would add 
provisions to specific sections to allow use of the 20 ppm standard.
    This addition of a lower bound concentration limit to the 
performance standard will also encourage use of devices that recover 
and allow for reuse of materials and will remove an inequity between 
requirements for different types of control equipment. With this 
additional control alternative, the requirements for process vents, 
storage vessels, vapor control devices applied to certain waste 
management units, and equipment leaks will be consistent with the 
requirements for transfer racks.
    This lower bound concentration standard is not being allowed as an 
option for compliance with the enclosed process unit alternative in 
Sec. 63.172 of subpart H or with the control requirements for surface 
impoundments subject to Sec. 63.134 of subpart G. The use of this lower 
bound concentration limit is considered inappropriate in those 
situations because of the large volumes of dilution air involved.
3. Recapture Devices
    The EPA is proposing to revise the rule to clarify the requirements 
for equipment such as adsorbers, condensers, and scrubbers that are 
used to recover materials (but not primarily for use, reuse, or sale), 
and are used to meet the control requirements. The proposed amendments 
introduce a new term, ``recapture device'', to identify these devices, 
which capture emissions and then send the material for ultimate 
disposal, revise the definition of control device to include this 
concept, and revise various sections of the rule to refer to recapture 
devices. Currently, the rule allows the use of control devices and 
recovery devices and specifies the applicable monitoring and 
recordkeeping requirements by type of equipment (e.g., adsorbers, 
etc.). However, the rule does not indicate how to treat a non-
combustion device that is not used as a recovery device (as defined in 
the rule).
    The EPA is proposing to revise the rule in this manner in order to 
address the regulatory void for non-combustion/non-recovery devices 
while preserving the approach used in this rule (and earlier rules) to 
differentiate between process and control in this industry. The 
existing definitions in the rule for recovery device and control device 
reflect the regulatory approach used in

[[Page 43705]]

the NSPS standards for process vents associated with distillation 
operations, air oxidation reactors, and other reactors. Under this 
approach, equipment is considered to be part of the process if the 
recovered materials are used, reused, or sold. The NSPS standards for 
process vents and the HON process vent provisions treated all 
condensers, adsorbers, scrubbers as ``recovery devices'' and never 
considered situations where this equipment could be used to capture the 
emissions and then send the material for ultimate disposal. Since these 
uses of these types of equipment do occur and the approach used to 
distinguish between process and control was an integral part of the 
data analysis used to support this rule, the EPA concluded that the 
best approach would be to define a new term to identify this additional 
category of equipment and to explicitly identify this equipment and the 
monitoring requirements in the rule.
4. Industrial Furnaces
    In today's amendments, the EPA is proposing to include RCRA-
regulated industrial furnaces under the HON's provisions for boilers. 
This change is being proposed because industrial furnaces, like other 
RCRA-regulated combustion devices, are subject to RCRA requirements 
which accomplish the same purpose as some HON provisions. For example, 
owners and operators are already required to demonstrate that 
industrial furnaces are capable of achieving the RCRA-required 
destruction and removal efficiency. A second performance test under the 
HON is not considered necessary. By amending the definition of 
``boiler'' to include industrial furnaces, the rule would treat 
industrial furnaces similarly to other RCRA-regulated combustion 
devices.
    The EPA has chosen to include industrial furnaces within an 
existing HON definition, the definition of ``boiler'', rather than 
creating separate regulatory provisions for industrial furnaces 
throughout subparts F, G and H. This decision is based on a desire to 
avoid making the HON longer and more complex. The EPA recognizes that 
some confusion may result from calling these devices ``boilers'' in the 
HON, when they are known as ``industrial furnaces'' under RCRA. 
However, this potential is small, and can be managed through 
appropriate definitions.
    The EPA considered several alternatives to using the definition of 
``boilers'' to address industrial furnaces. All these alternatives 
presented more serious difficulties than using the term ``boilers.'' 
For example, except for one instance in the wastewater provisions of 
subpart G (an error which is being corrected by these amendments), the 
HON does not use the term ``industrial furnace.'' In order to use that 
term consistently, it would have to be added to multiple locations 
throughout three subparts, and a new definition would probably be 
needed. In contrast, the provisions for ``boilers'' are already 
appropriate for industrial furnaces. Thus, the desired result can be 
accomplished with less revision of the regulatory text.
    The EPA also considered the option of calling these devices 
``incinerators'', because many industrial furnaces more closely 
resemble incinerators than boilers, i.e., they combust organic HAP 
without producing steam. However, in this case there would still be 
confusion because RCRA regulations differentiate between incinerators 
and industrial furnaces. Additionally, incinerators and industrial 
furnaces are regulated under different subparts of the RCRA 
regulations. This would make the HON's cross-references to RCRA 
regulations extremely complex, if the EPA attempted to address 
industrial furnaces in the existing HON provisions for incinerators. In 
contrast, boilers and industrial furnaces are regulated in the same 
subpart of the RCRA regulations (40 CFR part 266, subpart H), so that 
the existing cross-references may be used without revision. After 
balancing all these factors, the EPA concluded the best approach would 
be to include industrial furnaces within the HON definition of 
``boiler.''

E. Monitoring/Recordkeeping/Reporting Provisions

1. Correction to Monitoring Requirements for Acid Gas Scrubbers
    The EPA is also proposing corrections to the requirements for 
continuous monitoring of gas flow entering an acid gas scrubber. In 
cases where a scrubber is used after a combustion device for 
halogenated streams, subpart G currently requires that a flow meter 
with a continuous recorder be installed at the scrubber inlet to 
measure gas flow. The EPA has received new information that 
demonstrates that continuous monitoring of this acid gas stream is 
impractical due to the harsh conditions at the scrubber inlet. A 
continuous monitoring device would be expected to have a very short 
service life due to the combination of high temperature and 
corrosivity/low pH. Thus, it would be extremely costly to comply with 
the current requirement for continuous monitoring of gas stream flow. 
Therefore, the EPA is proposing to revise Sec. 63.114(a)(4)(ii) and 
Sec. 63.127(a)(4)(ii) to allow three different options for determining 
gas flow. Each of these options would provide sufficient data to 
determine a liquid/gas (L/G) ratio for use in monitoring operation of 
the acid gas scrubber.
    The first option being proposed would allow owners or operators to 
determine gas flow to the scrubber by using the design blower capacity, 
with appropriate adjustments for pressure drop. This would provide a 
``worst case'' gas flow. If the required compliance demonstration 
showed that a scrubber could meet the emission reduction requirements 
of subpart G for hydrogen halides and halogens during these worst-case 
flow conditions, the EPA anticipates that compliance would also be 
achieved during conditions of lower gas flow.
    In the second proposed option, the EPA recognizes that some post-
combustion scrubbers, regulated under RCRA, are already required to 
determine a L/G ratio to demonstrate compliance with emission reduction 
requirements. The EPA is proposing that methods of determining gas flow 
which have been utilized to comply with pre-existing RCRA regulations 
should also be acceptable for purposes of subpart G. This proposed 
option also provides that a determination made before the compliance 
date for this rule may be used in the compliance demonstration if it is 
still representative.
    Finally, the EPA is proposing that owners or operators may develop 
a gas flow determination plan. The plan would specify a reliable method 
for determining gas stream flow, to provide a representative or at 
least a worst-case flow rate during representative operating 
conditions. Recordkeeping requirements would apply. The EPA believes 
that this performance-oriented option is necessary due to the wide 
variety of technologies and process configurations in existence. For 
example, many SOCMI combustion units utilize multiple scrubbers in 
series. This may require a different approach to determining gas flow, 
than when a single scrubber is used.
2. Implementation Plans
    With today's proposed amendments, EPA is proposing to remove the 
requirement for submittal of implementation plans for existing sources' 
emission points that are not included in an emissions average. Under 
the April 22, 1994, rule, owners or operators, who have not yet 
submitted an operating permit application with the information 
specified in Sec. 63.152(e), were required

[[Page 43706]]

to submit by April 22, 1996, an implementation plan for points not 
included in an emissions average. On February 29, 1996 (61 FR 7716), 
this date was revised to December 31, 1996, to allow time for owners or 
operators of sources to consider recent changes to the rule and to 
allow for expected further revisions to the rule.
    This change is being proposed because it no longer appears that 
this report would serve a useful function, and the implementation plan 
for points not included in an emission average represents a duplicative 
and unnecessary burden with the Notification of Compliance Status. By 
December 31, 1996, many, if not most, sources will have already 
submitted the information covered by the implementation plan in permit 
applications. Any remaining sources will be covered by subsequent 
permit applications. Thus, the implementation plan requirement is 
redundant and, therefore, unnecessary. Furthermore, the implementation 
plan for points not included in an emission average would not have been 
subject to EPA approval. Finally, eliminating the implementation plan 
requirement would make the HON consistent with later MACT standards for 
the same types of emission points which have not required this report.
    It should not be inferred from this proposal to eliminate 
implementation plans for points not included in an emissions average 
that the requirement for an implementation plan for points included in 
an emission average will be eliminated. This report is needed to ensure 
that a proposed average will meet all the criteria in the rule and that 
it will result in credits exceeding the debits. Because of the 
complexities and site-specific nature of emissions averaging, this 
report will remain subject to EPA approval.
3. Startup/Shutdown/Malfunction Plans
    The EPA is proposing to revise several sections in the rule to 
clarify the requirements for start-up/shutdown/malfunction periods. 
These clarifications include revisions to the definitions of ``start-
up'' and ``shutdown'' and revisions to the monitoring and recordkeeping 
requirements in Sec. 63.152 of subpart G. These changes are being 
proposed to address several oversights in the original drafting and to 
make the requirements for start-ups/shutdowns/malfunctions more 
explicit to avoid potential misunderstanding of the requirements.
    Revisions are being proposed to the definitions for the terms 
``start-up'' and ``shutdown'' to make these terms more consistent and 
to extend these terms to include part of a cmpu (such as a wastewater 
tank) as well as the entire unit. The present definitions also do not 
apply to control equipment used to comply with the rule or to waste 
management units. Thus, if there were a start-up/shutdown/malfunction 
of an individual item of equipment or an item of equipment not 
presently included in the definition, it would not be permissible for 
the owner or operator to follow the start-up/shutdown/malfunction plan 
because it would not apply. Since it was intended that the start-up/
shutdown/malfunction plan would be followed in such situations, the 
definitions are being revised to reflect this intent. The definition of 
``start-up'' is also being revised to include activities associated 
with initial start-up, testing of equipment, and transitional 
conditions due to changes in product for flexible operation units. The 
current definition for ``start-up'' erroneously excludes these 
activities which should be addressed under the start-up/shutdown/
malfunction plan. The proposed revisions correct these drafting errors. 
As part of the correction to the definitions for ``start-up'' and 
``shutdown,'' EPA is also proposing to add two paragraphs to 
Sec. 63.102(a) to clarify operational requirements during periods of 
start-up/shutdown/malfunction. These provisions are necessary to avoid 
misuse of the revised definition of the term ``shutdown.''
    Revisions are being proposed for several paragraphs in Sec. 63.152 
to clarify that monitoring is not required during periods when the 
source is not operating and that the start-up/shutdown/malfunction plan 
details the monitoring requirements during periods when the plan is 
applicable. Currently, the rule does not explicitly address monitoring 
requirements during periods when the source is not operating. Because 
of concerns that this absence of direction could be interpreted as 
requiring monitoring after shutdown of a source, clarifying language is 
being proposed to remove any potential for misinterpretation. Minor 
revisions are proposed to Sec. 63.152, paragraphs (c) and (f) to 
clarify that data recorded during periods of start-up/shutdown/
malfunction are not excursions and are not to be included in averages 
of monitoring data. These changes are being made to ensure that it is 
clear that during periods of start-up/shutdown/malfunction the source 
is required to follow the procedures in the start-up/shutdown/
malfunction plan in lieu of requirements that would otherwise apply to 
the affected emission points under subpart G.
4. Alternative recordkeeping provisions
    Today's proposed changes to the rule include addition of new 
provisions to allow use of an alternative recordkeeping system that 
records fewer data points during periods of routine compliance provided 
the system meets specified criteria and the system is verified annually 
to meet the requirements. The proposed provisions would provide an 
alternative to the existing provisions in Sec. 63.152(f) for data 
compression systems. These new provisions are expected to reduce 
recordkeeping burden for some facilities.
    The proposed alternative recordkeeping provisions allow an owner or 
operator to use an exception-only recording system provided the system 
meets specified criteria and the system is demonstrated to operate 
properly initially, annually, and on demand. The new provisions require 
that the monitoring system be able to: (1) Detect abnormal or 
``impossible'' data (e.g., temperature reading of -200 deg.C on a 
boiler), (2) detect inappropriate ``flat-line'' data, (3) alarm at a 
set-point that is related to a limit on a parameter range, (4) generate 
a running daily average that could be used by plant personnel or to 
satisfy an inspector that the system is operating and the parameter is 
within established limits, and (5) allow a system check on demand 
during normal operations to verify that the system is recording data 
properly. A description of the monitoring system, and the most recent 
superseded description, must be retained. The current description would 
be retained at least 5 years and longer, if it has not been superseded. 
It must be retained either on-site or by a method that allows access 
within two hours after a request. The most recent superseded 
description would be retained for at least 5 years from its creation 
but could be stored off-site if it is more than six months old. If the 
superseded version is already more than 5 years old (at the time it 
becomes superseded) it may be discarded immediately. The facility would 
select the specific levels for the alarm set points considering the 
variability of the process operations and the control device stability 
under different operating conditions. It is expected that these alarm 
set points would be established at a level such that corrective action 
could be taken to prevent occurrence of a parameter excursion. The 
alternative provisions allow the owner or operator to retain

[[Page 43707]]

only the daily average value under most circumstances. If no excursions 
occur in a period of 6 consecutive months, the owner or operator is not 
required to record the daily average, but must record and retain weekly 
at least one parameter value during a period of operation other than a 
start-up, shutdown, or malfunction. If a non-excused excursion occurs, 
the owner or operator must immediately resume retaining the daily 
average value for each day. An owner or operator electing to use this 
alternative is required to notify EPA in the Notification of Compliance 
Status or periodic report with updates whenever there is a change in 
the frequency of data retention.
    The proposed alternative system in Sec. 63.152(g) differs from the 
alternative system for data compression systems provided in 
Sec. 63.152(f) and the existing continuous monitoring requirements in 
that the Sec. 63.152(g) alternative bases compliance on demonstration 
of a system and records for periods of abnormal operation. The EPA 
believes that this alternative provides an opportunity to use current 
technology to reduce the cost of monitoring and compliance 
demonstration. It is also anticipated that facilities electing to use 
these provisions will have better emission control than facilities not 
using an early warning type system. Because the system has to pass an 
initial, annual, and on demand performance demonstration, EPA believes 
that there are sufficient safeguards to ensure the system is operated 
properly.
5. Miscellaneous Clarifying Edits to Recordkeeping Requirements
    The proposed amendments to the rule include several other revisions 
to reduce the recordkeeping burden of the rule in addition to those 
described above. First, the proposed amendments include an additional 
alternative for cmpus that do not use as a reactant, or make as a 
product, any of the organic HAP's listed in table 2 of subpart F. 
Parallel changes are also being proposed for similar documentation 
requirements in subpart I. The new provisions, which would be added to 
Sec. 63.103(e) and Sec. 63.192(k), would allow an owner or operator to 
document the inapplicability of the rule on the request of an 
inspector. This alternative is being provided because it was never 
EPA's intent to impose an ongoing recordkeeping requirement on sources 
not subject to the rule and because the current provisions can be 
interpreted to impose such a requirement.
    EPA proposes to revise Sec. 63.103(c) to remove the requirement for 
an owner or operator to maintain copies of reports if the report has 
been sent to the EPA Regional Office and the State agency. If the EPA 
Regional Office has waived the requirement for submittal of reports to 
the Region, the owner or operator is not required to maintain copies of 
the reports. This revision is being made due to concern that misplacing 
a copy of a report would be a violation, even though the report had 
been properly submitted. This was not EPA's intent.
    It is also proposed to revise Sec. 63.103(c) to reduce the volume 
of records that must be stored on-site. Concern has been expressed that 
on-site storage is often limited and more costly than off-site storage. 
Subpart F currently requires the most recent 2 years' records to be 
stored on-site. The proposed revision would specify that at least 6 
months' records either be stored on-site or be available within 2 hours 
by any means. The remaining 4 and one-half years worth of records may 
be retained off-site. A definition of ``on-site'' would be added to 
clarify that the records may be kept anywhere at the source, such as a 
central filing area. These changes are being made to clarify what the 
necessary records are and to specify the performance objective, and not 
the method, that must be used to comply with the requirement.
    The proposed amendments to subpart F include revisions to 
Sec. 63.103(c)(2) documentation requirements for periods of start-up/
shutdown/malfunction. The proposed changes would make these provisions 
consistent with the requirements in subpart A (General Provisions) to 
document and report periods in which excess emissions occur. Another 
proposed change to reduce burden and simplify the reporting 
requirements is the elimination of the difference in submittal dates 
for reports sent by U.S. Mail and by other delivery services. This 
proposed revision to Sec. 63.103(d)(1) specifies that reports shall be 
submitted on or before the relevant dates and the provisions in 
Sec. 63.103(d)(1)(i) and (ii) would be removed from the rule. This 
change is being made to eliminate an unnecessary restriction.
    The proposed amendments include revisions to table 3 of subpart F 
to clarify the applicability of specific sections in subpart A to 
subpart H. Table 3 to subpart F currently does not explicitly detail 
the applicability of the requirements to subpart H, and there are some 
incorrect references to subpart A. The proposed revisions to the table 
correct these errors.
6. Miscellaneous Changes to Monitoring Requirements
    The EPA is proposing to clarify the instrument installation, 
calibration, operational, and maintenance requirements that occur 
throughout subpart G for instrumental monitoring of control devices. 
The current rule requires the owner or operator to follow the 
instrument manufacturer's recommendations for installation, 
calibration, and maintenance. The proposed revision would allow the 
owner or operator to develop a written procedure that provides adequate 
assurance that the equipment would reasonably be expected to monitor 
accurately. This revision is being proposed because many facilities in 
the SOCMI industry do not purchase off-the-shelf monitoring systems. 
Instead, it is common in this industry to develop monitoring systems 
from equipment purchased from several suppliers. Thus, it is likely 
that there are no manufacturer's instructions for the particular system 
installed. Even in cases where a monitoring system is purchased and 
used without substantial modification, the environment in which the 
instrument is operating may differ from the manufacturer's expected 
conditions sufficiently to make the manufacturer's recommendations 
meaningless or inappropriate. The proposed amendment would provide the 
necessary flexibility while preserving the intent to ensure accurate 
data.
    Today's proposed amendments also clarify that the requirement to 
monitor regeneration stream ``mass flow'' in carbon adsorbers means 
volumetric flow of the regeneration stream. This requirement occurs in 
several places in the rule (e.g., 40 CFR Sec. 63.114(b)(3)). The 
language in these sections is being revised because there is concern 
that the word ``mass'' might be misinterpreted as prohibiting existing 
types of monitoring that meet the intent of the requirement. The 
purpose of the requirement is simply to monitor to show that the carbon 
beds are being regenerated and maintained properly. While there are 
systems that provide a measure of the mass by monitoring several 
parameters and converting the results to mass, these systems as well as 
volumetric flow metering systems all start with measurements of volume. 
The proposed amendments replace all existing references to ``mass 
flow'' with ``mass or volumetric flow.''
    The EPA is also proposing to amend subpart G by revising the 
definition of ``flow indicator'' and by revising the regulatory 
language specifying the

[[Page 43708]]

requirement for monitoring by-pass lines (e.g. Sec. 63.114(d)(1)) to be 
consistent with the provisions and definitions in subpart H. The 
proposed definition includes reference to devices that detect the 
potential for diversion of a stream by methods other than ``flow'' 
monitoring and the by-pass monitoring requirements no longer refer 
exclusively to the presence of flow or imply that flow has to be 
measured. The revised definitions and rule provisions allow use of any 
means that will provide an indication of diversion of the stream from 
the control device.
7. Manual Recordkeeping Provisions
    The EPA is requesting comment on whether the provisions in 
Sec. 63.151(g)(3) for manual recordkeeping systems should be revised to 
allow requests for approval of monitoring on a less frequent basis than 
once every 15 minutes. The EPA has received requests that this 
provision allow monitoring once per 8-hour shift (or less frequently) 
if the owner or operator can demonstrate that operating parameters for 
the control device do not vary significantly over time. Examples of 
systems that the requestor believed should require only limited 
monitoring include condensers and acid gas scrubbers that vary slowly 
over time. The requestor believed that the present rule requirements 
impose a significant burden on facilities without automated recording 
systems since plant personnel would have to expend considerable time 
recording data.
    In previous decisions on requests for alternative monitoring 
systems for standards established under 40 CFR parts 60 and 61, EPA has 
sometimes allowed less frequent monitoring based on consideration of 
the level of the actual emissions in relation to the standard and the 
control technology stability. These reviews have considered the process 
operating characteristics and the nature of the types of control 
problems that could occur. In situations where it is extremely unlikely 
that a significant emission event could go undetected, less frequent 
monitoring has been allowed. If EPA were to revise subpart G to allow 
less frequent monitoring for facilities with manual recordkeeping 
systems, it is likely that the provisions would require that the 
emission point be operated at a level substantially below the level of 
the standard (e.g., a TRE greater than 4, a 99 percent reduction when 
the rule requires a 95 percent reduction, or a substantially lower 
emission rate than allowed), and its availability would be limited to 
certain control technologies. Monitoring less frequently than once per 
hour might be appropriate for carbon adsorbers and some absorbers but 
less frequent monitoring would not be appropriate for equipment such as 
condensers. Adsorbers tend to exhibit failure over a relatively long 
period of time while condensers can fail quickly if a compressor fails 
or if flow rates through the condenser are increased significantly. 
Monitoring a condenser once a day could permit a significant undetected 
emissions episode. The EPA is not currently proposing a reduced 
frequency of monitoring. However, the EPA requests comment on the need 
for a reduced frequency as well as the appropriate criteria for 
allowing the use of less frequent monitoring (such as once per shift) 
and the basis for the recommended criteria.

F. Overlap with Other Regulations

1. Benzene Waste NESHAP
    The April 22, 1994 rule requires that sources with wastewater 
streams subject to control requirements in the HON and Benzene Waste 
NESHAP (40 CFR part 61, subpart FF) comply with both rules. Since April 
1994, members of the regulated community have objected that this 
requirement unnecessarily increases the cost of demonstrating 
compliance and complicates management of environmental programs at a 
facility without providing a corresponding environmental benefit. To 
address these concerns, EPA is proposing to add a compliance option to 
Sec. 63.110(e)(1) that would allow some consolidation of the 
inspection, monitoring, recordkeeping, and reporting requirements of 
these two NESHAP.
    The proposed amendments would allow an owner or operator to use the 
wastewater provisions of this rule as compliance with the provisions of 
the Benzene Waste NESHAP provided two conditions are met. First, the 
owner or operator must comply with the wastewater provisions of subpart 
G. Second, for any Group 2 wastewater or organic stream whose benzene 
emissions are subject to control under the provisions of the Benzene 
Waste NESHAP, the owner or operator will comply with the requirements 
for Group 1 wastewater streams in subpart G for that stream. This 
proposed additional compliance option is designed to maintain the 
applicability and stringency of existing control requirements for the 
Benzene Waste NESHAP while providing an opportunity to reduce the 
complexity of the compliance demonstration by reducing the number of 
separate rules that apply to the equipment. The number of streams that 
are subject to control under the Benzene Waste NESHAP would not be 
changed by electing to use this option. The EPA wishes to emphasize 
that this additional compliance option would not supersede any 
existing, still-effective agreements to take mitigating actions that 
were granted in exchange for additional compliance time with the 
Benzene Waste NESHAP. These agreements would not be altered by this 
proposed amendment to this rule.
2. Resource Conservation and Recovery Act (RCRA)
    In developing the April 1994 rule, EPA attempted to address the 
problem of overlapping requirements by specifying which provisions 
apply for each of the known cases of overlapping rules. These 
instructions on overlapping requirements were provided in Sec. 63.110 
of subpart G and in Sec. 63.160 of subpart H. Since issuance of the 
rule, EPA has learned that there is another broad category of 
overlapping RCRA requirements that was not addressed in the April 1994 
rule. In today's amendments, EPA is proposing provisions to allow use 
of certain RCRA-required monitoring to satisfy corresponding 
requirements in subpart G and H. These proposed provisions would be 
added to these subparts as Sec. 63.110(h) and Sec. 63.172(n).
    The April 1994 rule addressed the known overlaps of control 
requirements between the RCRA rules in 40 CFR parts 260 through 272 and 
the wastewater control requirements of this rule. Due to an oversight, 
the April 1994 rule did not specify the applicable requirements in 
cases where the same control device (e.g., incinerator or adsorber) is 
subject to a RCRA rule and would be used to comply with requirements 
for non-wastewater provisions of this rule. Presently, the April 1994 
rule would require the owner or operator to comply with the applicable 
monitoring, recordkeeping, and reporting provisions of each rule. 
Compliance with both rules' monitoring, recordkeeping, and reporting 
requirements would significantly increase the cost of compliance 
demonstrations without providing a corresponding environmental benefit. 
To reduce this unnecessary burden, the EPA is proposing to allow an 
owner or operator to elect to use the monitoring, recordkeeping, and 
reporting requirements in 40 CFR parts 260 through 272 for this rule.
    The EPA considers this proposed consolidation of overlapping 
monitoring, recordkeeping, and reporting requirements to be appropriate

[[Page 43709]]

because the RCRA air rules and the HON have the same objective and 
monitor similar operational characteristics of control devices. In 
general, the RCRA requirements tend to require more frequent monitoring 
and retention of more detailed information. Therefore, it is possible 
to use the RCRA data and reports to demonstrate compliance with the 
provisions of this rule.
    Today's amendments also propose to accept demonstrations of 
compliance with RCRA requirements as demonstration of compliance with 
the process vent, transfer operations, storage vessels, and equipment 
leak provisions of the HON. The wastewater provisions in subpart G 
presently exempt hazardous waste incinerators permitted under 40 CFR 
part 270 and boilers and industrial furnaces permitted under 40 CFR 
part 266 from performance test requirements of Sec. 63.139. These RCRA 
air rules were judged to be at least as stringent in controlling air 
emissions as this rule so that a second compliance demonstration was 
not necessary. This judgment is applicable to the control requirements 
for the non-wastewater provisions of this rule. Therefore, it is 
proposed to add these rules to the list of controls exempted from 
performance tests or other compliance demonstration requirements in 
Sec. 63.116(b), Sec. 63.128(c), and Sec. 63.139(d)(4) and to add 
provisions to Sec. 63.120(d) to list controls exempt from compliance 
demonstration requirements.

G. Proposed Changes to Subparts H and I

    In addition to the applicable changes discussed in earlier sections 
of this preamble, the proposed changes to subpart H consist of: (1) 
clarification of the terms ``repaired'' and ``first attempt at repair'' 
and clarification of the followup monitoring requirements for 
connectors and valves; (2) correction of Sec. 63.180(b)(4) to allow use 
of calibration gases other than methane; and (3) miscellaneous 
corrections and clarifications to the wording of a few paragraphs.
1. Clarification of Definitions
    The EPA is proposing to revise the definitions of the terms 
``repaired'' and ``first attempt at repair.'' These proposed changes 
are intended to eliminate the confusion that presently exists regarding 
what monitoring is required after leaks are repaired. The definition of 
``repaired'' presently states that the equipment is adjusted or 
otherwise altered to eliminate a leak. The EPA has received inquiries 
whether this definition implies that there must be proof by monitoring 
data that the leak was repaired. These questions have been raised 
because other sections of subpart H impose such a requirement. Because 
of inquiries such as these, EPA reviewed subpart H and determined that 
the confusion regarding the requirement was due in part to the lack of 
specificity in the definition of the terms ``repaired'' and ``first 
attempt at repair.'' The proposed amendments to subpart H would revise 
these definitions to explicitly include reference to verification 
monitoring according to the procedures in Sec. 63.180(b) and (c), as 
appropriate. From this review, it was also determined that some of the 
confusion was arising from lack of specific statement in applicable 
sections of the rule that verification monitoring was required. The 
proposed changes to subpart H would correct this problem.
2. Followup Monitoring
    The EPA has received inquiries regarding the requirements for 
monitoring within 3 months after repair of a leaking valve and the 
relationship between this monitoring and the periodic monitoring 
required by the standard. The proposed amendments would add provisions 
to Sec. 63.168(f)(3) to clarify that (1) monitoring is conducted 
according to the procedures specified in Sec. 63.180 (b) and (c) and 
(2) the periodic monitoring may be used to satisfy this requirement if 
the timing of this monitoring coincides with the timing specified for 
the followup monitoring. The new provisions that would be added to 
Sec. 63.168(f)(3) would also specify how to consider the results of 
this monitoring in the calculation of percent leaking valves should a 
leak be detected. These proposed changes would revise the rule to 
correct oversights in the original drafting and to ensure that the rule 
reflects EPA's intent.
    The EPA has also received inquiries regarding whether subpart H 
requires followup monitoring of connectors found to be leaking. These 
questions have arisen due to a lack of clarity in Sec. 63.174 (c)(1)(i) 
and (c)(1)(ii) that these provisions apply to connectors that have been 
opened. The proposed change to the rule would clarify this point.
3. Calibration Gases Other Than Methane
    The EPA is proposing to revise Sec. 63.180(b)(4) to allow use of 
calibration gases other than methane. Since April 1994, some industry 
representatives and equipment vendors have expressed concern to EPA 
that present restriction to use methane as the calibration gas 
precludes use of the procedures in Method 21 which permit calibration 
with another reference compound. As discussed in the April 22, 1994 
Federal Register, EPA intended to allow the use of reference compounds 
other than methane in the calibration gases. However, due to a drafting 
error Sec. 63.180(b)(4)(ii) was not modified to allow this flexibility. 
The proposed amendments to this section of the rule would revise this 
paragraph to allow the use of other compounds when the instrument does 
not respond to methane or does not meet the performance specifications 
of Sec. 63.180(b)(2)(i). The EPA considered whether this revision 
should include a requirement to adjust the instrument readings to a 
methane base in order to have the readings on the same basis as 
instruments calibrated using methane. The proposed provisions do not 
require such an adjustment for the same reasons given in the April 22, 
1994 notice for removal of the 1992 proposed rule's requirement of 
adjustment for response factors (59 FR 19447-19448).

Changes to Subpart I

    The proposed changes to subpart I consist of corrections of several 
cross-referencing errors and revisions to the general recordkeeping and 
reporting requirements in Sec. 63.190(f). The proposed amendments to 
Sec. 63.190(f) are the same as the revisions to Sec. 63.103(c) 
discussed in section III. E. 5 of this preamble.

IV. Basis for Proposed Changes to Wastewater Provisions

A. General Comments on Changes to Wastewater Provisions

    Today the Agency is proposing amendments to the wastewater 
provisions in subpart G that are designed to clarify provisions of the 
rule that have been misunderstood by some in the SOCMI industry. If 
promulgated, the proposed clarifying amendments would not change the 
basic control requirements, predicted emission reductions, or cost of 
the rule. A summary of the amendments is provided in the following 
paragraphs.
    Four sections have been rewritten entirely in today's amendments to 
improve clarity and to incorporate the new ``point of determination'' 
concept discussed in section IV.D of this preamble. The four sections 
address: criteria for determining the Group 1 and Group 2 wastewater 
streams (Sec. 63.132); performance standards for process wastewater 
(Sec. 63.138); procedures for determining Group 1 and Group 2 
wastewater streams (Sec. 63.144); and procedures for demonstrating

[[Page 43710]]

compliance (Sec. 63.145). Also, requirements allowing the use of 
floating flexible membrane covers on surface impoundments have been 
added to Sec. 63.134, and a section addressing in-process equipment 
(Sec. 63.149) has been added.
    Minor changes are proposed to the sections governing waste 
management units, control devices, delay of repair of waste management 
units, inspections and monitoring, recordkeeping, and reporting.
    As a result, today's wastewater provisions are being proposed in 
Secs. 63.132 through 63.147, in Sec. 63.149, in tables 8 through 20, in 
tables 34 through 37, and in figure 1 of appendix A to subpart G. 
Deletions include Sec. 63.131 (reserved since information became 
unnecessary with amendments) and the figures and tables 14a, 14b, and 
16 to subpart G. The proposed amendments would add a new table 15, 
which replaces tables 15a and 15b of the April 1994 rule, and tables 35 
through 37 and figure 1, which provides a key to the terms in the 
wastewater equations. Fraction measured values (Fm) in Table 34 were 
corrected for four compounds: trichlorophenol, Fm=0.11; chlorobenzene, 
Fm=1.00; isophorone, Fm=0.51; and 1,1,2-trichloroethane, Fm=1.00. In 
addition, tables 11, 12, 17, and 18 were revised.

B. Wastewater Definitions

1. Summary of Significant Changes
    Significant changes proposed are: revisions to the ``wastewater'' 
definition; replacement of the ``point of generation'' (POG) definition 
with ``point of determination'' (POD) definition; addition of 
``closed'' and ``open biological treatment process'' definitions; 
addition of the ``enhanced biological treatment system'' definition; 
revisions to the ``individual drain system'' definition; and deletion 
of definitions for ``total volatile organic hazardous air pollutant 
(VOHAP)'', ``volatile organic concentration'', and ``VOHAP 
concentration.''
    Changes to some of the definitions, especially ``wastewater'', 
``recovery device'', and ``point of generation'', were necessary due to 
circularity and a lack of specificity in the definitions. The 
definitions were revised to clarify EPA's intent concerning which 
organic HAP-containing waters are in-process fluids regulated by the 
provisions in Sec. 63.149 and which are wastewater and regulated by the 
provisions in Sec. 63.132 through Sec. 63.147.
2. Revised Wastewater Definition
    The most significant change proposed today to the ``wastewater'' 
definition is the addition of the concept of ``discard.'' The discard 
concept is fundamental in distinguishing which fluids exiting the cmpu 
are subject to the HON wastewater provisions in Secs. 63.132 through 
63.147. Together with the point of determination and in-process 
equipment concepts, the revised definition of wastewater makes 
decision-making for facilities and regulatory authorities more 
straightforward, and the rule more easily implemented. Since fluids in 
the in-process equipment are also controlled by the HON, emission 
reductions will not be affected by this proposed change.
3. Replaced Point of Generation With Point of Determination
    Today's proposal would change the definition for ``point of 
generation'' in two ways--one way a conceptual change and the other a 
change in terminology. ``Point of generation'' was changed to ``point 
of determination'' to distinguish it from the term, ``point of 
generation'' as used in the Benzene Waste NESHAP. ``Point of 
generation'' was defined in the April 1994 rule as ``the location where 
process wastewater exits the process unit equipment,'' (i.e. exits the 
last recovery device). In today's proposal, it has been replaced by 
``point of determination'', which is defined as ``each point where the 
process wastewater exits the chemical manufacturing process unit.'' The 
need for and significance of this change is discussed in more detail in 
section IV.D. of this preamble.
4. Recovery Device
    The proposed amendments include a revised definition of ``recovery 
device.'' The proposed definition of ``recovery device'' differs from 
the existing definition in order to reflect the revised approach to the 
definition of ``wastewater'' and to reflect the fact that deviations 
from normal operations do occur.
    Under the revised approach for defining wastewater, a stream does 
not become wastewater until it exits the last recovery device. As a 
recovery device had been defined as an item of equipment used to 
recover chemicals for fuel value, use, reuse, or ``sale'', it would 
seem impossible--by definition--to sell a wastewater stream or residual 
extracted from a wastewater stream. In developing the revised approach 
for wastewater, it became apparent that using the term ``sale'' without 
any qualification in the definition of ``recovery device'' left a 
potential loophole. A bad actor could ``sell'' a Group 1 stream to an 
affiliate for a negligible amount, claim that it was a sale so that the 
stream had not yet exited the last recovery device (so it was not 
wastewater), and the affiliate could simply dispose of the stream or 
residual without treating it in accordance with the HON provisions (and 
incurring the costs of such treatment). The additional language is 
intended to remove the possibility of such sham transactions by 
limiting the concept of sales to sales for the same general purposes 
for which chemicals may be recovered and utilized within the HON 
facility (i.e.,use, reuse, or burning as fuel). The EPA believes that 
such language is broad enough to encompass any sale that is not a sham 
since ``use'' and ``reuse'' are very general concepts. The definition 
also differs from the existing definition in that the word ``normally'' 
now modifies the phrase ``used for the purpose of recovering ....'' 
This change was made to recognize that occasional exceptions to normal 
usage can and will arise.
5. Added Definitions for Closed Biological Treatment Process, Open 
Biological Treatment Process, and Enhanced Biological Unit
    Definitions for closed biological treatment process, open 
biological treatment process, and enhanced biological treatment system 
would be added to the definitions in subpart G. The new definitions are 
necessary to make distinctions among biological treatment processes 
which allow the incorporation of more flexible and less burdensome 
compliance demonstrations for some facilities. This is discussed in 
more detail in the discussion of changes to Sec. 63.145 in section 
IV.F. of this preamble.
6. Modified Individual Drain System Definition
    The definition for individual drain system would be modified to 
clarify three key concepts and incorporate minor wording changes. The 
definition in today's proposal would clarify that only stationary 
systems are included in the definition; that individual drain systems 
are used to convey residuals as well as wastewater streams; and that 
the individual drain system does not include in-process equipment as 
described in Sec. 63.149.

[[Page 43711]]

7. Deletion of Total VOHAP, VO Concentration, and VOHAP Concentration 
Definitions
    The EPA proposes to delete the definitions for ``total VOHAP'', 
``VO concentration'', and ``VOHAP concentration.'' As discussed in 
section IV.F. of this preamble, these terms would no longer be used in 
the rule; therefore, the definitions would not be needed.

C. Changes to Sec. 63.132

    In the April 1994 rule and in today's proposed changes to the rule, 
Sec. 63.132 provides the instructions on how to determine if a process 
wastewater stream requires control and the general outline of 
requirements for process wastewater streams. The general approach for 
determining which wastewater streams are Group 1 or Group 2 would not 
change. Determination of whether a wastewater stream is Group 1 or 
Group 2 would still be based on the same concentration and flow rate 
criteria as the current rule. Control requirements for Group 1 
wastewater streams still require that HAP emissions be controlled until 
the HAPs are either removed from the wastewater or destroyed. Today's 
proposal reorganizes Sec. 63.132 to eliminate redundant sections, 
clarify requirements, and change the order of the provisions into a 
more reader friendly format. Other proposed changes include use of the 
point of determination concept instead of the point of generation 
concept (discussed in IV.D. of this preamble) and the addition of 
language prohibiting the discard of certain organic material into water 
or wastewater.
    Language prohibiting the discard of certain organic material into 
water or wastewater would be added as Sec. 63.132(f). Specifically, 
liquid or solid organic materials containing greater than 10,000 parts 
per million of Table 9 compounds may not be discarded into water or 
wastewater unless the receiving stream is managed and treated as a 
Group 1 wastewater stream. The prohibition would exclude equipment 
leaks; activities included in the start-up/shutdown/malfunction plan, 
including maintenance wastewater; spills; and samples. This paragraph 
would be added to eliminate the potential for dumping of high 
concentration organic streams, such as off-specification product, into 
the sewer. The EPA seeks comment on the appropriate size of a sample.

D. Basis of Determining Group Status of a Wastewater Stream: Change 
From Point of Generation to Point of Determination

    The EPA is proposing to revise the rule to base the determination 
of applicability of control requirements to a wastewater stream on its 
characteristics at the point where the wastewater stream exits the last 
recovery device instead of at the point of generation (POG). The new 
location for determining the characteristics of a wastewater stream is 
being called the point of determination (POD) to distinguish it from 
the POG concept used in other air rules for waste and wastewater such 
as the Benzene Waste NESHAP. As discussed earlier in the OVERVIEW OF 
CHANGES TO THE RULE, this proposed revision is one of several changes 
being made to address problems with drafting clarity and structure of 
the wastewater provisions. The proposed concept of POD along with the 
revised definitions for key wastewater terms and the provisions for in-
process equipment subject to the provisions of Sec. 63.149 is 
consistent with the emission and cost estimates used to support the 
April 1994 rule.
1. Point of Generation Concept in April 1994 Rule
    In the April 1994 rule, the term POG is defined as the point where 
the process wastewater exits the process unit equipment. The EPA's 
intent with the POG approach was to identify wastewater streams for 
control prior to opportunities for losses due to emissions to the 
atmosphere, prior to dilution with other wastewater streams, and prior 
to partial treatment of the wastewater stream. If dilution or partial 
treatment prior to a control determination were allowed, some 
wastewater streams that would have required control based on the 
concentration criteria would not meet the requirement of the rule for 
control and would therefore not be treated.
    A fundamental premise of the POG concept is that a clear 
distinction can be made between process equipment and waste management 
units. In development of the April 1994 rule, EPA emphasized that the 
distinction was based on whether the material and the unit in which it 
is managed is an integral part of the production process. The EPA has 
learned since 1994 that industry has numerous interpretations of the 
concept of ``integral to the process'' and hence the POG concept. 
Interpretations vary because evaluation of what is integral to the 
process takes into consideration economic and process design factors as 
well as knowledge of the process and the industry. Because processes 
and configurations of equipment in facilities subject to this rule vary 
widely, it is difficult to develop a set of criteria that can be used 
to make clear distinctions between process and waste management 
equipment. The combination of this problem with the ambiguities and the 
lack of specificity in the other key wastewater definitions (e.g., 
wastewater) has resulted in a rule that may be misinterpreted. It is 
important that the rule be clear and unambiguous so that all parties 
interpret its requirements consistently.
    Because of issues raised since promulgation of the April 1994 rule 
concerning EPA's intent and the difficulty of making the POG 
determination, the EPA has reevaluated the POG concept. As part of this 
reevaluation, EPA reviewed the data that were used to develop the 
emission and cost estimates for the April 1994 rule. It was determined 
from this review that the industry responses in 1990 to the section 114 
wastewater questionnaires did not reflect a consistent understanding of 
what EPA considered to be wastewater and what EPA meant by the concept 
of POG. In many cases, the respondents provided information for a 
location that was after the point that EPA considered to be the POG. In 
a few cases, it was not possible to determine from the process 
description and the description of wastewater streams whether the 
information was or was not after the POG. Thus, because of the lack of 
consistency in the responses, it is not possible to be certain that the 
emission and cost analyses used in development of the April 1994 rule 
reflected the POG concept in the rule language. Moreover, it is now 
apparent that the POG approach is inherently foreign to the way 
facility operators view their processes and it is unlikely that this 
concept would be generally accepted and understood by the regulated 
community. Because of these practical problems, the EPA concluded that 
it was appropriate to develop a new approach for the initial point of 
evaluation of a wastewater stream. The new approach that would replace 
the POG is called the point of determination (POD).
2. Point of Determination Concept in Today's Proposal
    The EPA's intent in developing the POD approach is to have a 
decision criterion that is replicable and unequivocally specifies the 
location for evaluation of a wastewater stream for

[[Page 43712]]

the purposes of control. The POD therefore encompasses each point where 
process wastewater exits the last recovery device. This proposed 
definition of POD would allow a facility to recover chemicals for fuel 
value, use, reuse or for sale for fuel value, use, or reuse. As with 
the POG, under the POD approach owners/operators would not be allowed 
to mix streams together for the purpose of escaping compliance by the 
diluting of wastewater streams to a level below the 1000 ppmw at 10 L/
min or greater flowrate or the 10,000 ppmw at any flowrate level. Under 
the POD approach, process units conveying process fluids in the 
chemical manufacturing process unit are subject to the requirements 
established in Table 35. Table 35 is consistent with the suppression 
requirement for a wastewater stream requiring control. Again, the EPA's 
intent is to allow process fluids that have recovery potential to be 
sent to recovery devices; however, these fluids are required to be 
managed so as to minimize the potential for losses due to emissions to 
the atmosphere. In addition, making the POD the location after the last 
recovery unit would eliminate the need for the recycle option allowed 
under the current wastewater provisions.
    The EPA believes the POD approach would allow more flexibility than 
currently provided in the rule with regard to materials recovery while 
eliminating confusion over the initial point of evaluation for a 
wastewater stream for the purposes of control and, at the same time, 
maintain the suppression requirements for more concentrated streams. 
The POD approach would also make the wastewater provisions consistent 
with the data collected for development of the rule and with the other 
provisions in the rule concerning definition of process. There are no 
expected changes in emission reductions or costs associated with this 
revision to the rule.
    The EPA considers the proposed POD approach to provide a workable 
alternative to the POG approach because the HON addresses the other 
emission points in the cmpu. The EPA does not believe that the POD 
approach would be appropriate for other rules that are not as 
comprehensive in the coverage of emission points. The POD concept would 
not be appropriate in cases where it is known that the other emission 
points would not be subject to any control requirements.

E. Changes to Waste Management Unit Provisions

1. Clarifications to Process Wastewater Provisions
    The proposed clarifications to the text concern the mixing of 
wastewater in tanks, methods to insure a water seal is maintained, use 
of a flexible shield restricting wind motion across the space between 
the discharging pipe and the receiving drain, and venting from junction 
boxes. Text was added to explain that alternative methods (other than 
the example given in the rule) could be used to demonstrate that water 
seals are maintained properly. Clarification was added to the 
requirements concerning the flexible shield to describe more fully 
where the shield should be located. The proposed clarification for the 
venting of junction boxes was written to explain the difference between 
venting to the atmosphere of junction boxes with gravity wastewater 
flow and venting to the atmosphere of junction boxes with wastewater 
pumps. Under today's proposed clarification to the provisions, water 
sealed junction boxes with gravity flow or systems that operate with 
only slight fluctuations in the liquid level are allowed to vent to the 
atmosphere through a specified size of vent pipe. Junction boxes with 
pumps that turn on and off, allowing the junction box to alternately 
empty and fill, are not allowed to vent to the atmosphere due to the 
vapor headspace turnover that occurs. Clarifications were made to the 
process wastewater provisions for wastewater tanks to express more 
fully the EPA's intent to suppress emissions from these systems.
2. Floating Membrane Covers
    Since April 1994 the EPA has received inquires as to the reason 
floating membrane covers were not allowed under the wastewater 
provisions of the HON. The EPA has allowed the use of floating membrane 
covers in other rules. The EPA considered this inquiry and decided that 
floating membrane covers would be acceptable for suppressing emissions 
from surface impoundments. Provisions would be added to the surface 
impoundment requirements derived from the standards in Subpart QQ of 40 
CFR part 63 for floating membrane covers. The provisions provide the 
requirements for the material used for construction of the floating 
membrane cover and for the installation of the cover.
3. Individual Drain System Suppression Requirements
    Since promulgation of the April 1994 rule, industry has raised 
concerns that the individual drain system suppression requirements 
would lead to vapor lock in wastewater collection systems. A vapor lock 
occurs in a wastewater system when the wastewater attempts to flow into 
or out of an area that is sealed and the pressure in the system cannot 
equalize, thereby restricting the flow of the wastewater. The EPA's 
intent is to suppress emissions from the collection system and not to 
seal the system such that gravity flow systems will be inoperative. The 
concern over potential for vapor lock to occur in the individual drain 
system would be addressed by removing the requirement to gasket and 
latch covers or openings.
    In today's proposed amendments, the requirement to seal, gasket, or 
latch covers or openings in the individual drain system has been 
deleted. The proposed amended text would now read that openings shall 
be equipped with a tight fitting solid cover (i.e., no visible gaps, 
cracks, or holes). The EPA believes that this requirement would 
minimize emissions from openings in wastewater treatment systems and 
can be met without creating a vapor lock. The EPA recognizes that 
normally there will be a ``visible'' point of juncture between the 
cover and the opening, such as where a manhole cover contacts the 
manhole frame. The point of juncture generally is a thin, visible line 
or crack running around the circumference of the cover. These points of 
juncture are not prohibited. The intent is to prohibit gaps or openings 
that allow air flow into or out of the collection system. A tightly 
fitting solid cover will contact the manhole frame in such a way that 
there is a surface (cover) to surface (frame) contact. Certain minor 
surface irregularities, such as those associated with a manhole cover 
manufactured by casting, are acceptable. A gap between surfaces that 
are not intended for sealing is acceptable. For example, a gap between 
the outer rim of a manhole cover and the inner rim of the manhole is 
acceptable, if the actual sealing surface is between the bottom of the 
cover and the top of the manhole. Plugged or capped holes (such as 
plugged or capped holes to insert a tool for removal of a cover) are 
acceptable. Removal of the plugs or caps is unacceptable, except for 
the purpose of conducting those activities for which the rule allows 
the cover to be opened and provided the plug or cap is replaced upon 
completion of the activity. Warped covers that create a gap for air 
passage

[[Page 43713]]

are unacceptable. The EPA believes that relaxing the requirements for 
tightly fitting solid covers for individual drain systems will suppress 
emissions effectively while also allowing small changes in pressure to 
occur in the system and, thereby, eliminating the problem from vapor 
lock.
4. Repair Time Allowed for Waste Management Units
    The April 1994 rule provides that repair can be delayed for up to 
15 or 45 days depending on the type of waste management unit. The EPA 
has received requests that 45 days be allowed for repair of all types 
of waste management units. This change was requested in order to 
simplify implementation of the rule. The EPA evaluated the need for 
additional time for repairs for some types of units and determined that 
the April 1994 rule provisions did not address situations where parts 
could not be obtained in the specified time period. In addition, due to 
an oversight, Sec. 63.140 did not allow delay of repair when the waste 
management unit was taken out of service. As a result, EPA is proposing 
revisions to Sec. 63.140 to allow delay of repair when waste management 
units are taken out of service and when additional time is necessary to 
obtain spare parts. The proposed revisions do not revise the time 
provided for repair of some waste management units from 15 days to 45 
days.

F. Changes to Secs. 63.138, 63.144, and 63.145

1. General
    Three sections of today's proposed rule, Secs. 63.138, 63.144, and 
63.145, were rewritten to improve clarity, to incorporate the point of 
determination concept, and to add flexibility in the compliance 
demonstration for facilities using biological treatment processes to 
achieve the control requirements. Revisions to Sec. 63.144 in the April 
1994 rule contained in today's proposal are reorganization for clarity; 
addition of methods and an alternative validation procedure; deletion 
of the term VOHAP from text; and deletion of simple equations that are 
unnecessary. These three sections are discussed together because the 
changes made to one of them most likely appears in all three of the 
sections. A specific change will be discussed where it first appears or 
has the most impact.
2. Changes to Sec. 63.138, Process Wastewater Provisions--Performance 
Standards for Treatment Processes Managing Group 1 Wastewater Streams 
and/or Residuals Removed From Group 1 Wastewater Streams
    Section 63.138 contains provisions for control of Group 1 
wastewater streams and residuals from Group 1 wastewater streams. The 
most significant changes proposed to Sec. 63.138 are: reorganization 
for clarity; deletion of recycling and process unit alternative as 
control options; technical corrections to the design steam stripper 
specifications and removal of unnecessary specification of steam 
quality; clarification of compliance demonstration procedures that may 
be used for biological treatment processes; clarification that 
treatment in series is allowed; consolidation of provisions for the 1 
megagram source-wide exemption into Sec. 63.138; and clarification of 
when design evaluations may be used to demonstrate compliance instead 
of performance tests.
3. Deletion of Recycling and Process Unit Alternative Options From 
Sec. 63.138
    The recycling and process unit alternative options (April 1994 rule 
paragraphs (b)(1)(i), (c)(1)(i), (d)(2)(ii), and (h)(1), and paragraph 
(d), respectively) would be deleted from today's proposed rule. Both 
options would become unnecessary under the POD concept proposed to 
replace the POG concept. The recycling option allowed an owner or 
operator to achieve compliance by recycling a process stream to a 
process unit. The recycling provisions in paragraph (f) of the April 
1994 rule require that the wastewater or residual not be exposed to the 
atmosphere and that waste management units in contact with the 
wastewater streams or residual comply with control and inspection and 
monitoring requirements. With the proposed point of determination 
concept, the recycling option would become redundant because as long as 
a fluid stays in the process, it would not be a wastewater subject to 
the provisions of Sec. 63.138; instead, it would be subject to the 
other provisions of the rule such as storage vessels or Sec. 63.149.
4. Clarification That Treatment in Series Is Allowed
    Although it is not stated clearly, the April 1994 rule intended 
that more than one treatment process could be used to comply with the 
rule. Today's proposed amendments would provide provisions for 
treatment in series in Secs. 63.138 and 63.145 and would clarify EPA's 
intent. Treatment in series may be used whether or not treatment 
processes are connected by hard piping. However, inlet and outlet mass 
flow rate determination for compliance demonstration differ, depending 
on whether hard piping is used to connect treatment processes and 
whether a biological treatment process is part of the series.
5. Consolidation of Provisions for the One Megagram Source-Wide 
Exemption Into Sec. 63.138
    The provisions for the 1 megagram source-wide option would be 
clarified and would be consolidated from Secs. 63.138 and 63.144 in the 
April 1994 rule into Sec. 63.138 in today's proposed amendments. This 
would make the provisions easier to find and understand for the reader.
6. Alternative Methods to Method 305 used in Sec. 63.144
    The EPA is proposing to revise the rule to allow use of alternative 
methods for Group 1 or Group 2 determinations for process wastewater 
streams in lieu of Method 305. The EPA specifically reviewed Methods 
624, 625, 1624, and 1625 and has determined that these methods may be 
used with certain additional requirements. These requirements are 
specified in Sec. 63.144 (b) of the proposed amendments. Other methods 
may be used if they are validated by the Method 301 validation 
procedure as discussed below. Because the alternative methods determine 
actual concentrations of the organic compounds, the fraction measured 
(Fm) values listed in table 34 can be used to adjust the alternative 
method measurements to a value representative of what Method 305 would 
provide.
    Method 305 was developed by EPA to identify streams requiring 
control for air emissions; therefore, the method was developed 
specifically to retain and measure organic compounds of concern from an 
air emission perspective. The Office of Water methods (Methods 624, 
625, 1624, and 1625) were developed for different purposes and would 
not necessarily address air concerns as does Method 305. The EPA used 
four criteria of concern from the air perspective to evaluate the 
methods. These four criteria were used to ensure that the alternative 
method retained and quantified the organic compounds of concern, 
generally referred to as target compounds. The first criterion is that 
the method provide a sampling approach that would minimize the loss of 
volatiles from the sample while maintaining sample integrity. The 
second criterion is that the method

[[Page 43714]]

detect the organic compounds of concern. Third, the method must have 
adequate up-front quality assurance and quality control to ensure valid 
data. Finally, the alternative method must correct for analyte 
preparation and analysis bias. That is, the method adjusts to the 
actual concentration of the compound in the sample.
    The EPA has compared Methods 624, 625, 1624, and 1625 against the 
four criteria listed above and proposes to allow these methods to be 
used as alternative methods to Method 305 with some additional 
requirements as specified in the proposed revised rule. The EPA is 
proposing to allow the use of alternative methods based on the belief 
that those parties using this alternative approach are following the 
procedures specified in the alternative method and are not using some 
modified version of the method. One of the additional requirements 
proposed consists of employing a sampling and collection procedure that 
minimizes the volatilization of organics. For Method 625, EPA proposes 
to require corrections to the compounds for which the analysis is being 
conducted. For example, Method 624 requires initial calibration of the 
analytical system with the target compounds. The four methods also 
specify the list of analytes for which the method can be used. 
Additional compounds may be added to the four reviewed methods' analyte 
lists by using the Office of Water's Alternative Test Procedure (40 CFR 
136.4 and 136.5).
    Additional methods other than those previously mentioned also may 
be used in lieu of Method 305 if a procedure that minimizes loss of 
volatile organic compounds during sampling and collection is employed 
and if the method is validated in accordance with sections 5.1 or 5.3, 
and the corresponding calculations in sections 6.1 or 6.3, of Method 
301. Other EPA methods may be validated using Appendix D of part 63, 
``Alternative Validation Procedure for EPA Waste Methods'', provided 
that a procedure that minimizes loss of volatile organic compounds 
during sampling and collection is also be employed.
7. Deletion of Term ``Volatile Organic Hazardous Air Pollutant''
    The EPA found that many in the regulated community found the 
terminology ``volatile organic hazardous air pollutant'' (VOHAP) 
confusing. The term VOHAP concentration is used in the April 1994 rule 
to mean the weight concentration of Table 9 HAP's as determined by 
Method 305. This meant when a VOHAP concentration was required, the 
results from methods other than Method 305 had to be adjusted by the 
compound-specific fraction measured factor (Fm) listed in table 34 of 
subpart G to convert actual concentration to Method 305 concentration. 
When the April 1994 rule specified a HAP concentration, results from 
Method 305 were required to be adjusted by the Fm factors to correct to 
the actual concentration while results from other methods would be used 
as measured (without Fm adjustment).
    With today's proposed amendments, Secs. 63.144 and 63.145 of the 
rule would explicitly state when Fm adjustments are appropriate rather 
than relying on using the term VOHAP to convey EPA's intent. The 
proposed amendments would also remove the term VOHAP. Also under the 
proposed amendments, it would be clarified in Sec. 63.144 that annual 
average concentration may be expressed either as adjusted by the Fm 
factors or with no adjustment.
8. Changes to Sec. 63.145, Process Wastewater--Test Methods and 
Procedures to Determine Compliance
    Section 63.145 contains the provisions that explain how to 
demonstrate compliance with the performance standards in Sec. 63.138. 
Several significant changes are proposed to this section. It was 
rewritten to improve drafting quality, provide clear statements of 
EPA's intent, and correct errors.
9. Reorganization of Sec. 63.145
    In today's proposal, Sec. 63.145 is reorganized to clarify 
requirements and provide the reader with an understanding of which 
paragraphs to use for demonstrating compliance with the compliance 
options in Sec. 63.138. Three clarifications are of particular note: 
(1) ``Representative operating conditions'' for treatment processes and 
control devices are specified in paragraphs (a)(3) and (a)(4) of 
Sec. 63.145; (2) conditions under which a performance test or design 
evaluation is allowed or under which neither is required are specified 
in paragraphs (a)(1) and (a)(2); and, (3) clarification of when Fm 
adjustments are allowed are included throughout the section. These 
proposed clarifications were in the April 1994 rule but may have been 
unclear or placed in other sections, causing readers difficulty in 
determining how the sections fit together. The reorganized section 
would also make provisions for measuring concentration and flow rate 
consistent among paragraphs. EPA believes these changes in rule 
language will improve clarity and will improve reader comprehension.
10. Demonstrating Compliance for Biological Treatment Processes
    Concerns have been raised that the requirements concerning 
demonstrating compliance for biological treatment processes are 
confusing and the requirement for site-specific fraction biodegraded 
(Fbio) determinations is unnecessarily burdensome. To respond to these 
concerns, the EPA reevaluated the performance determination 
requirements for biological treatment processes and found that 
adjustments could be made to the requirements consistent with the 
intent of the rule. The EPA's intent was to allow the use of biological 
treatment units that achieved the required mass removal of table 9 
compounds through biodegradation and not through emissions to the 
atmosphere. Today's proposed amendments would add paragraph (h) which 
describes how to determine the site-specific fraction of Table 8 and/or 
Table 9 compounds biodegradated (Fbio); clarify that biological 
treatment processes must use one of the required mass removal options 
to comply with the rule; add flexibility in demonstrating compliance 
for biological treatment processes; and add provisions that allow a 
subset of the Table 8 or Table 9 compounds to be used to demonstrate 
compliance.
    Paragraph (h)--how to determine Fbio--is added to make the 
provisions easier to find than in the April 1994 rule. In addition, 
Sec. 63.145(h), together with appendix C to part 63, provide more 
flexibility to the owner or operator to demonstrate compliance for 
biological treatment processes. The April 1994 rule required owners and 
operators using biological treatment processes to demonstrate 
compliance using appendix C to part 63 to determine Fbio. Today's 
proposal recognizes that for some biological treatment processes, a 
less rigorous determination of Fbio is sufficient to demonstrate 
compliance.
    When a biological treatment process is used, one of the required 
mass removal options, Sec. 63.138(f) or (g), must be chosen as the 
compliance option. This was EPA's intent in the April 1994 rule but it 
was not stated clearly. The provisions that may be used to demonstrate 
compliance depend on whether the biological treatment process is open 
or closed. In each case, the proposed rule specifies which compliance 
demonstration provisions may be used.
    For open biological treatment processes, volatilization is an 
important

[[Page 43715]]

concern. Therefore, to demonstrate compliance, the owner or operator 
must determine the mass of the Table 8 or Table 9 compounds that is 
removed due to biodegradation rather than volatilization. If the open 
biological treatment process is an enhanced biological treatment 
process, the source would have more flexibility in demonstrating 
compliance. To incorporate this flexibility, EPA looked at the Table 9 
compounds and determined which are more readily biodegraded and which 
are more likely to volatilize before biodegradation can occur in an 
enhanced biological treatment process.
11. Performance Requirements for Open Biological Treatment Processes
    Because of the reevaluation of the Table 9 compounds, the EPA was 
able to separate the compounds on Table 9 into three lists which appear 
in table 36. These lists would be used together with other provisions 
to specify how the source may demonstrate compliance. Table 36 may only 
be used for wastewater streams treated in an enhanced biological 
treatment system as defined by the proposed revisions to the rule.
    The development of the three lists in table 36 was based on the 
individual compound's fraction emitted (Fe), fraction removed in a 
steam stripper (Fr), and fraction biodegraded in a biological treatment 
unit (Fbio). The values for Fe and Fr that were evaluated were based on 
analysis performed for the April 1994 rule. Documentation of this 
analysis is available in the docket A-90-23. The Fbio values used to 
compile the three lists in table 36 were based on default values for an 
enhanced biological treatment unit from the EPA Water8 model. List 1 
consists of Table 9 compounds that have Fr values approximately equal 
to or less than their Fbio values, and Fe values that are in the middle 
to lower volatility range. List 3 consists of Table 9 compounds that 
have Fr values of 0.99, Fbio values that are considerably lower than 
0.99, and Fe values in the higher volatility range. The Table 9 
compounds that were left after this evaluation became List 2.
    A performance demonstration would not be required for enhanced 
biological treatment systems that receive wastewater streams that 
require control and that contain only List 1 compounds on table 36. An 
example would be an activated sludge unit that meets the proposed 
enhanced biological treatment system definition and treats Group 1 
wastewater streams that contain only methanol and nitrobenzene (List 1 
compounds). A compliance demonstration would not be required because 
the only Table 9 compounds requiring control appear on List 1. For 
enhanced biological treatment systems treating wastewater containing 
compounds on Lists 1, 2, and/or 3, a performance demonstration is 
required.
    Today's proposal offers several techniques for demonstrating 
compliance for an open biological treatment unit meeting the proposed 
definition of an enhanced biological treatment system. The 
demonstration is performed by estimating the Fbio for the system using 
the first order biodegradation constant (K1) and the forms in appendix 
C to part 63. The owner/operator may use any of the procedures 
specified in 40 CFR part 63, appendix C to calculate the site-specific 
K1s for compounds on Lists 1 and/or 2. The owner/operator may elect not 
to calculate site-specific biodegradation rate constants but instead to 
calculate Fbio for the List 1 compounds using the defaults for K1s in 
table 37 and to follow the procedure explained in Form IIA of appendix 
C. For compounds on List 3, the owner/operator is allowed to use any of 
the procedures specified in 40 CFR part 63, appendix C, except the 
batch tests procedure, to calculate the site-specific K1. Biological 
treatment units not meeting the definition of an enhanced biological 
treatment system are allowed to determine the Fbio using the site-
specific K1 values determined by any of the procedures in appendix C to 
part 63 except the proposed batch tests procedure.
    The EPA believes that today's proposed revisions to the biological 
treatment option adds additional flexibility without sacrificing 
reduction of emissions. By separating the Table 9 compounds into 3 
lists and allowing different performance requirements depending on the 
properties of the compounds on the lists, additional options have been 
made available to the owner/operator. The EPA maintained the original 
intent of the rule by limiting the additional options to biological 
units meeting the definition for enhanced biological treatment systems.
    The flexibility allowed by not requiring that the site-specific 
fraction biodegraded be determined for all Table 8 or Table 9 compounds 
in the wastewater stream is predicated on the underlying assumption 
that the wastewater is treated in an enhanced biological treatment 
system. The definition for enhanced biological treatment system is 
proposed in today's notice. The definition is based on extensive 
discussions with individuals knowledgeable in the area of biological 
treatment. Well-designed, operated, and maintained activated sludge 
systems meet the definition of enhanced biological treatment systems.
12. Equations in Sec. 63.145
    Many of the equations in Sec. 63.145 would be revised to make 
mathematical corrections or to make the equations consistent with the 
rest of the rule. The equations for control devices performance tests--
paragraph (i) in today's proposal--are proposed to be based on the 
equation in the process vents section of the rule rather than the 
equations in the April 1994 rule. The terms in the equations were 
changed to make them consistent. Figure 1 in appendix A to subpart G 
lists the new terms.
13. Compounds Not Required To Be Considered in Performance Tests
    Today's proposal would add Sec. 63.145(a)(6) which specifies when 
compounds are not required to be included in a performance test. These 
provisions were added because EPA recognizes that not all Table 8 or 
Table 9 compounds are present in a wastewater stream; and not all 
compounds need to be measured to demonstrate compliance, i.e., 
measuring a predominant compound may be enough to show the mass removal 
necessary to achieve compliance. These provisions would also provide 
that compounds present at concentrations less than 1 ppmw at the POD or 
compounds present at the POD at concentrations less than the lower 
detection limit where the lower detection limit is greater than 1 ppmw 
may be excluded from the performance test. This provision was added to 
avoid imposing an unnecessary analytical burden.

G. Off-Site Treatment

    Today's proposed amendments include provisions to allow owners and 
operators of HON sources to transfer Group 1 wastewater streams or 
residuals off-site for treatment provided the owner/operator obtains 
from the transferee a copy of a written statement submitted by the 
transferee to EPA certifying that the transferee will manage and treat 
the wastewater streams or residuals in accordance with the HON's 
provisions. These new provisions replace the existing provisions in 
Sec. 63.132(j) that required that the owner/operator ensure that the 
transferee complies with the suppression and treatment requirements of 
the rule. The existing provisions in Sec. 63.132(j) are revised to 
provide a means to allow transfers of treatment responsibility without 
imposing liability

[[Page 43716]]

for actions of another party on the owner/operator of the HON source.
    The new provisions allowing for off-site or on-site third party 
treatment require the owner/operator transferring the wastewater stream 
or residual to comply with the suppression requirements specified in 
Secs. 63.133 through 63.137 of this subpart for each waste management 
unit that receives or manages a Group 1 wastewater stream or residual 
removed from a Group 1 wastewater stream prior to shipment or 
transport. The owner or operator may not transfer the wastewater stream 
or residual unless the transferee has submitted to EPA a written 
certification that the transferee will manage and treat, in accordance 
with subpart G, any Group 1 wastewater stream or residual removed from 
a Group 1 wastewater stream that was received from a source subject to 
the requirements of this subpart. The owner or operator has to notify 
the third party treater that the wastewater stream or residual has to 
be handled and treated in accordance with the requirements of the rule.
    The statements of compliance with the rule by third party treaters 
need only be submitted to EPA; the provisions do not contain or 
envision any requirements that EPA approve the written statements 
before shipments of wastewater streams or residuals to off-site 
treaters are permitted. The proposed provisions provide, however, that 
EPA may revoke or suspend a certification statement in the event the 
off-site treater violates the pertinent HON wastewater provisions. The 
proposed provisions also require that the written statement from the 
off-site treater contain a statement that EPA has not revoked or 
suspended a certification statement within the previous three years. 
The intent of this is to provide an adequate incentive for compliance 
on the part of the off-site treaters.
    The proposed provisions also differ from the existing requirements 
in Sec. 63.132(j) for notice from the owner/operator of the HON source 
in that the requirement that notice be provided at least once a year in 
the case of continuous shipments is replaced by a requirement only for 
notice at the outset of such shipments and when there is a change in 
the required treatment. In drafting the revised language, the general 
statements of the obligation on off-site treaters in the old 
Sec. 63.132(j)(3) have been replaced with explicit cross references to 
the applicable requirements. This change is proposed to provide a 
clearer statement of the applicable requirements and to minimize 
potential for misunderstandings. This change is not considered to be a 
substantive change in the requirements for off-site treaters. Another 
change of significance in the provisions for third party treaters 
concerns the concept of sale. The phrase in the opening paragraph of 
Sec. 63.132(j), permitting the sale of Group 1 wastewater streams or 
residuals ``for any other purpose'' has been eliminated in the proposed 
replacement provisions. This change is necessary in light of the 
revised approach to defining wastewater. Inherent in the new approach 
is the concept that a stream is not wastewater unless it is being 
discarded. Thus, the concept of selling wastewater is inherently 
inconsistent.

H. Addition of Sec. 63.149 and Table 35

    The proposed amendments to add a new Sec. 63.149 and table 35 to 
subpart G are an outgrowth of the change from the POG concept of the 
April 1994 rule to the POD concept in these proposed amendments. The 
purpose of this new section is to ensure that the organic HAP 
containing fluids are properly managed in closed systems. Table 35 
lists the applicable requirements for drain or drain hub, manhole, lift 
station, trench, oil/water separator, and tank.

I. Proposed Changes to Appendix C of Part 63

    The EPA is proposing to revise appendix C to part 63 to clarify the 
language and to add an additional procedure for determining the 
fraction biodegraded in a biological treatment unit. The new procedure 
added to appendix C is called the Batch test procedure.
    Appendix C contains instruction on how to determine the fraction 
biodegraded in a biological treatment unit. Today's proposal addresses 
several issues concerning Appendix C. The first issue concerns problems 
with concentrations below the detection limit for the effluent stream 
from the Method 304 benchscale reactor. Another issue involving the 
Method 304 reactor is the time and expense required to operate the 
benchscale reactor. Both of these issues would be addressed by the 
addition of the Batch tests procedure to appendix C. The proposed rule 
amendments would allow owners and operators to use the batch tests to 
determine first order biodegradation constants for compounds on Lists 1 
and/or 2 of table 34 treated in a unit meeting the definition of an 
enhanced biological treatment process. (See the discussion of 
performance requirements for open biological treatment processes for 
further information.)
    The Batch tests procedure consists of the aerated reactor test and 
the sealed reactor test. These two tests are less time intensive, and 
thereby less expensive, than the Method 304 procedure. These two tests 
are used widely in industry to design biological treatment units. Basic 
instructions for the two tests are being added to appendix C; however, 
these tests should be conducted only by persons familiar with 
procedures for determining biodegradation kinetics. References were 
supplied in appendix C for further information.
    The appendix C requirements would be clarified by explaining that 
every compound present in the wastewater would not be required to have 
a site-specific, first order biodegradation constant determined. The 
owner or operator can assume the first order biodegradation constant is 
zero for any compound as long as the required mass removal can be 
demonstrated.

J. Proposed Changes to Methods 304A and 304B

    The EPA is proposing to make minor revisions to Methods 304A and 
304B that would clarify several points and eliminate prescriptive 
details while maintaining the quality of the data. Methods 304A and 
304B are procedures that may be used to determine the biodegradation 
rates of organic compounds in biological treatment processes. The 
proposed revisions consist of making the terminology consistent and 
allowing more flexibility in the setup and operation of the methods. 
The section discussing the oxygen control system would be clarified. 
References to reactor or bioreactor would be changed to benchtop 
bioreactor for consistency. Additional flexibility would be added 
throughout the method in numerous ways such as eliminating the 
requirement for a specific size reactor or a specific blower, not 
requiring a specific hydraulic residence time, allowing alteration of 
the operation of the Method 304 unit to increase the effluent 
concentration above the limit of quantitation, and other ways. The EPA 
believes these changes will allow owners and operators more flexibility 
while maintaining the original intent of the method.

K. Alternative Control Techniques (ACT) for Industrial Wastewater

    The EPA believes that today's proposal makes the Industrial 
Wastewater ACT internally inconsistent and is recommending that States 
consider the revisions to the HON wastewater provisions definitions and 
control approaches as discussed below when regulating sources covered 
by the ACT. When issued in April 1994, the

[[Page 43717]]

ACT consisted of three documents: a September, 1992 draft Industrial 
Wastewater Control Techniques Guideline (CTG); Revisions to Impacts of 
the Draft Industrial Wastewater CTG; and the HON wastewater provisions 
(as promulgated in 1994) as the model rule. The ACT was issued to 
assist States in selecting Reasonably Available Control Technology 
(RACT) for control of volatile organic compounds (VOC) from wastewater 
at Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) 
Facilities, Pharmaceutical Plants, Pesticide Sources, and Hazardous 
Waste Treatment Storage and Disposal Facilities in ozone nonattainment 
areas. In today's action, the EPA is proposing fundamental changes to 
the wastewater provisions of the HON. The EPA believes that these 
proposed amendments will result in a more effective and better-
understood regulation. Thus, some aspects of the ACT are inconsistent 
with the revised wastewater provisions in the HON, and should not be 
used without considering the intent of the control requirements and 
these proposed revisions.
    The Agency's intent has been and continues to be that the 
wastewater collection and treatment control philosophy will be 
consistent between the Industrial Wastewater ACT and the HON. Although 
the ACT and the HON address somewhat different pollutants (not all 
VOC's are HAP's, and vice-versa), the technologies and control 
requirements were deliberately made consistent. Specifically, the 
wastewater collection and treatment control philosophy is a basic 
approach designed to minimize emissions from designated wastewater 
streams meeting a certain concentration and flow rate. The approach 
requires control of the transfer of the designated streams to a 
treatment unit, treating the wastewater to a specified level, and 
controlling emissions from the treatment unit. Although the basic 
wastewater control philosophy will be the same between the HON and the 
ACT, there will be major differences. The Industrial Wastewater ACT and 
the HON will continue to differ in the compounds that are the basis for 
control; the ACT addresses VOC emissions and the HON is concerned with 
HAP emissions. The HON is a national standard for portions of the 
chemical industry while the Industrial Wastewater ACT addresses 
facilities in ozone non-attainment areas in four separate industry 
groups, including a broader definition of the chemical industry. The 
EPA still believes the RACT recommendation presented in the Draft 
Industrial Wastewater CTG is reasonable; however the State agency 
should consider all information presented in the Industrial Wastewater 
ACT and the HON along with additional information about specific 
sources to which the regulation applies.
    To cite a few examples of changes to the HON that should be 
considered by those referencing the Industrial Wastewater ACT: the 
principle of a ``point of generation'' is being revised substantially 
and renamed ``point of determination''; the definition of 
``wastewater'' is being revised; and requirements are being added for 
control of emissions from certain in-process streams. If the ``point of 
determination'' approach is adopted, the State agency should ensure 
that provisions similar to those in proposed section 63.149 are also 
adopted.

V. Administrative Requirements

A. Paperwork Reduction Act

    The information collection requirements of the previously 
promulgated NESHAP were submitted to and approved by the Office of 
Management and Budget (OMB). A copy of this Information Collection 
Request (ICR) document (OMB control number 1414.02) may be obtained 
from Sandy Farmer, Information Policy Branch (2136); U.S. Environmental 
Protection Agency; 401 M Street, SW; Washington, DC 20460 or by calling 
(202) 260-2740.
    Today's changes to the NESHAP should have no impact on the 
information collection burden estimates made previously. The changes 
consist of new definitions, alternative test procedures, and 
clarifications of requirements. The changes are not additional 
requirements. Consequently, the ICR has not been revised.

B. Executive Order 12866 Review

    Under Executive Order 12866, the EPA must determine whether the 
proposed regulatory action is ``significant'' and, therefore, subject 
to the OMB review and the requirements of the Executive Order. The 
Order defines ``significant'' regulatory action as one that is likely 
to lead to a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety in State, local, or tribal governments or communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs, or the rights and obligations of 
recipients thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    The HON rule promulgated on April 22, 1994, was considered 
``significant'' under Executive Order 12866, and a regulatory impact 
analysis (RIA) was prepared. The amendments proposed today would 
clarify the rule and correct structural problems with the drafting of 
some sections. The proposed amendments do not add any new control 
requirements. Therefore, this regulatory action is considered not 
significant.

C. Regulatory Flexibility Act

    Pursuant to section 605(b) of the Regulatory Flexibility Act, 5 
U.S.C. 605(b), as amended, Pub. L. 104-121, 110 Stat. 847, EPA 
certifies that this rule will not have a significant economic impact on 
a substantial number of small entities and therefore no initial 
regulatory flexibility analysis under section 604(a) of the Act is 
required. For the reasons discussed in the April 22, 1994 Federal 
Register (59 FR 19449), this rule does not have a significant impact on 
a substantial number of small entities. The proposed changes to the 
rule are merely corrections and revisions that do not add new control 
requirements to the April 1994 rule. Therefore, the proposed changes 
are also not considered significant.

D. Unfunded Mandates

    Under section 202 of the Unfunded Mandates Reform Act of 1995 
(``Unfunded Mandates Act''), the EPA must prepare a budgetary impact 
statement to accompany any proposed or final rule that includes a 
Federal mandate that may result in estimated costs to State, local, or 
tribal governments in the aggregate, or to the private sector, of $100 
million or more. Under section 205, the EPA must select the most cost-
effective and least burdensome alternative that achieves the objectives 
of the rule and is consistent with statutory requirements. Section 203 
requires the EPA to establish a plan for informing and advising any 
small governments that may be significantly or uniquely impacted by the 
rule.
    The EPA has determined that the action promulgated today does not 
include a Federal mandate that may result in estimated costs of $100 
million or more to either State, local, or tribal governments in the 
aggregate or to the

[[Page 43718]]

private sector. Therefore, the requirements of the Unfunded Mandates 
Act do not apply to this action.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Reporting and recordkeeping requirements.

    Dated: August 15, 1996.
Carol M. Browner,
Administrator.
[FR Doc. 96-21280 Filed 8-23-96; 8:45 am]
BILLING CODE 6560-50-P