United States
Environmental
Protection Agency
Solid Waste and
Emergency Response
(5305W) 	
EPA530-R-99-058
PB2000-101 898
February 2000
RCRA, Superfund & EPCRA
Hotline Training Module
Introduction to:
Air Emissions
(40 CFR Parts 264/265, Subparts AA, BB, and CC)
Updated October 1999

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DISCLAIMER
This document was developed by Booz-Allen & Hamilton Inc. under contract 68-WO-0G39 to EPA. It is intended to
be used as a training tool for Hotline specialists and does not represent a statement of EPA policy.
The information in this document is not by any means a complete representation ofEPA's regulations or policies.
This document is used only in the capacity of the Hotline training and is not used as a reference tool on Hotline calLs.
The Hotline revises and updates this document as regulatory pro gram areas change.
The information in this docume nt may not necessarily reflect the current position ofthe Agency. This document is
not intended and cannot be relied upon to create any rights, substantive or procedural, enforceable by any party in
litigation with the United States.
RCRA, Superfund & EPCRA Hotline Phone Numbers
National toll-free (outside of DC area)
Local number (within DC area)
National toll-free for the hearing impaired (TDD)
(800) 424-9346
(703) 412-9810
(800) 553-7672
The Hotline is open from 9 am to 6 pm Eastern Time,
Monday through Friday, except for federal holidays.

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AIR EMISSION STANDARDS
CONTENTS
1.	Introduction 							 1
2.	Air Pollution Overview									 2
2.1	Ozone	 2
2.2	Air Toxics 			 2
3.	Regulatory Summary									 3
3.1	Subpart AA 	 4
3.2	Subpart BB												 8
3.3	Subpart CC	 11
4.	Special Issues	 15
4.1	Permit-as-a-Shield					 15
4.2	Interface with Clean Air Act			 15
4.3	Applicability of Subparts AA and BB to Large Quantity Generators		 15

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Air Emissions - 1
1. INTRODUCTION
The Resource Conservation and Recovery Act (RCRA) requires the safe and effective
management of hazardous waste from the point of generation to ultimate disposal. In
1984, as part of the Hazardous and Solid Waste Amendments (HSWA), Congress
established land disposal restrictions (LDR) which require that hazardous wastes be
treated to meet specific standards prior to land disposal. These restrictions impose
treatment standards on RCRA hazardous wastes to ensure that wastes are treated
before they are placed on the land to minimize any future release of hazardous
constituents to soil and groundwater. Some of the treatment technologies that are used
to meet these standards, however, release hazardous constituents to the air during the
treatment process. Thus, while treating hazardous waste prior to land disposal can
protect groundwater, releases to the air can diminish this benefit by shifting the
pollution from one environmental medium to another. This is called "cross-media
pollution." In order to minimize the threat of this type of pollution, HSWA added
§3004(n) to RCRA, granting EPA the authority to promulgate regulations for
monitoring and control of air emissions resulting from RCRA hazardous waste
management activities as necessary to protect human health and the environment.
This module provides a regulatory overview of the RCRA air emissions standards as
they apply to hazardous waste facilities. When you complete this module, you will be
able to explain the history of the RCRA air emission standards as well as the air
emission controls required by the standards. Specifically, you will be able to:
•	Explain the difference between the air emission standards in Part 264/265,
Subparts AA, BB, and CC
•	Summarize the requirements of each of these subparts
•	Identify the types of units subject to these requirements as well as specific
exemptions.
Use this list of objectives to check your understanding of this topic after you complete
the training session.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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2 - Air Emissions
2. AIR POLLUTION OVERVIEW
The need to control organic air emissions from waste management sources stems from
the adverse affects that volatile organics can have on human health and the
environment. EPA estimates that approximately eight percent of the nation's volatile
organic emissions are produced by hazardous waste treatment, storage, and disposal
facilities (TSDFs). When establishing the RCRA air emission standards, EPA focused on
two major concerns: ozone and air toxics.
2.1	OZONE
The effects of ozone on air quality can be both beneficial and detrimental to human
health and the environment. In the presence of sunlight, organic compounds (including
those emitted from waste management facilities) undergo a series of complex chemical
reactions to form two by-products: ozone and aerosol. The aerosol that is formed
restricts visibility and creates photochemical smog. Ozone has been proven to yield
harmful effects as well. Ozone exists in both the earth's upper atmosphere
(stratosphere) and the lower atmosphere (troposphere). In the stratosphere, ozone
protects us from the damaging effects of the sun's radiation by acting as a filtering
mechanism. In the troposphere, however, exposure to ozone has been shown to have
more severe effects, including inflammation of lungs, impaired breathing, reduced
breathing capacity, coughing, chest pain, and nausea.
2.2	AIR TOXICS
Air toxics are air pollutants that can cause cancer or other adverse health effects.
Sources of these pollutants include large industrial settings such as chemical plants,
petroleum refineries, and power plants, as well as more diverse sources such as dry
cleaners and paint manufacturers.
Of the 189 chemicals currently identified as hazardous air pollutants under the Clean
Air Act (CAA), a significant number are organic compounds. Exposure to these
pollutants can affect neurological, respiratory, and reproductive systems.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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Air Emissions - 3
3. REGULATORY SUMMARY
EPA has the specific authority to control organic air emissions at RCRA hazardous
waste facilities (§3004(n)). Under this authority, EPA's approach to controlling organic
air emissions is designed to significantly reduce these emissions as a class rather than
controlling the emission of individual waste constituents. Thus, instead of regulating
certain organic compounds, the RCRA air emission standards are established according
to the type of waste management activity involved and the ways in which the emissions
occur.
The RCRA air emission standards were promulgated in phases. The first phase
includes 40 CFR Part 264/265, Subparts A A and BB. These subparts address air
emissions from process vents associated with certain types of hazardous waste
management processes (Subpart AA) and leaks from certain types of equipment at
TSDFs and large quantity generators (Subpart BB). At such facilities, owners and
operators are required to install control equipment and employ management practices
to reduce air emissions from affected units and equipment.
Phase II of the RCRA air emission standards, Part 264/265, Subpart CC, regulates
organic air emissions from tanks, surface impoundments, and containers located at
RCRA TSDFs and large quantity generators (LQGs). The last phase of the RCRA air
emission standards, Phase III, is dependent on the ability of Subparts AA, BB, and CC to
effectively reduce volatile organic emissions. If there is still a significant risk posed by
organic air emissions, EPA will develop additional air emissions standards on an
industry-specific basis. Phases I and II of the RCRA air emission standards are
discussed in this module.
There is no difference between the air emission standards in Part 264 and Part 265,
except for reporting requirements. There are no reporting requirements under Part 265
for owners and operators of interim status TSDFs, or for large quantity generators.
Thus, any reference made in this module to a particular section of 40 CFR may be
applied to the requirements contained in either Part 264 or 265, unless otherwise noted.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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4 - Air Emissions
3.1 SUBPART A A
The following types of units are subject to the Subpart AA process vent standards:
•	Units subject to the permitting standards of Part 270 (i.e., permitted or interim
status)
•	Recycling units located at hazardous waste management facilities otherwise
subject to the permitting standards of Part 270 (i.e., independent of the recycling
unit, the facility has a RCRA permit or is in interim status)
•	Less than 90-day large quantity generator units.
Although most recycling units are exempt from regulation under RCRA, §261.6(d)
subjects certain recycling units to the Subpart AA standards. Thus, owners and
operators of recycling units located at facilities that already have a RCRA permit or are
operating in interim status must also comply with the applicable Subpart AA
regulations.
Any unit exempt from the facility standards under §§264/265.1 is not subject to the
process vent standards of Subpart AA. For example, a wastewater treatment unit that
otherwise meets the applicability criteria of Subpart AA would not be subject to the
standards, since the unit is exempt from Part 264/265 (§264.1(g)(6), §265.1(c)(10)).
Once the owner and operator have determined that a facility is subject to Subpart AA,
they must consider additional applicability criteria to determine whether the facility is
subject to the air emission control requirements.
Subpart AA applies to six specific types of units that have associated process vents:
steam strippers, distillation units, fractionation units, thin-film evaporation units,
solvent extraction units, and air strippers. For purposes of the RCRA air regulations, a
process vent is any open-ended pipe or stack that is vented to the atmosphere either
directly, through a vacuum-producing system, or through a tank associated with one of
the six specific types of units (§264.1031). Owners and operators at affected facilities
that have process vents associated with one of these types of units will be required to
meet the standards of Subpart AA if they manage wastes with an organic concentration
of at least 10 parts per million by weight (ppmw). Figure 1 summarizes the
applicability of the Subpart AA standards.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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Air Emissions - 5
	Figure 1	
SUBPART AA APPLICABILITY TREE
Is the unit:
Permitted or interim status?	No
Recycling unit at permitted/interim status facility?	____
Large quantity generator accumulating hazardous waste?
Yes
J
Is the unit one of the following types of units?
Distillation
Fractionation
Thin-film evaporation
Solvent extraction
Air stripping
Steam stripping
Yes
Is the unit exempt under §§264/265.1?
No
J
Is the unit associated with a process vent as
defined in §264.1031?
Yes
Does the unit manage hazardous waste with an
organic concentration >10 ppmw?
J
No
Yes
No
No
Yes
Subject to Subpart AA	Not subject to Subpart AA
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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6 - Air Emissions
AIR EMISSION CONTROL REQUIREMENTS
Owners and operators of facilities subject to Subpart AA must install control
mechanisms that meet one of two standards presented in the regulations. Owners and
operators may reduce or destroy the organics in the wastestream to meet either of the
following conditions (§265.1032(a)):
•	Reduction of organic air emissions from vents covered by the standards to both
3.0 pounds per hour (1.4 kg/h) and 3.1 tons per year (2.8 Mg/y)
or
•	Reduction of organic air emissions at the facility by 95 percent by weight.
These figures are based on aggregated emissions from all vents at the facility that are
subject to Subpart AA. As long as the facility meets the numerical standards, owners
and operators have the flexibility of reducing some units by a large amount and others
by a lesser amount or not at all. This allows owners and operators to evaluate all
alternatives available and achieve the most cost-effective means of complying with the
standards.
CLOSED VENT SYSTEMS AND CONTROL DEVICES
In order to meet the air emission standards discussed above, Subpart AA requires
owners and operators to install and operate control devices on affected units at the
facility in order to remove or destroy organics in its emissions. EPA does not specify
the type of control device that must be used to achieve these standards; however,
individual performance requirements for some types of devices that may be used are
presented in the regulations to assist owners and operators in complying with the
requirements. These include vapor recovery systems, enclosed combustion devices,
and flares. Owners and operators may use other types of control devices as long as the
emission reduction requirements of §265.1032(a) are met.
As mentioned above, it is not necessary for every affected unit at the facility to be
equipped with a control device. The emission standards in §265.1032(a) are imposed on
a facility-wide basis; thus, if installing control devices on half of the affected units at the
facility is sufficient to bring organic emissions below the allowable levels, any
remaining units at the facility that are subject to Subpart AA may continue to operate
with no control devices.
In addition to control devices, owners and operators must also install closed-vent
systems to conduct the organics to the control device. A closed-vent system is a system
that is not open to the atmosphere and that is composed of piping and connections that
transport gas or vapor from a piece or pieces of equipment to a control device
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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Air Emissions - 7
(§264.1031). These systems must be designed arid operated with no detectable
emissions, and periodically inspected and monitored for emissions.
Inspection and Monitoring
To ensure proper operation and maintenance, owners and operators must monitor and
inspect each closed-vent system and control device used to comply with Subpart A A
(§265.1033(f)). Each control device must be inspected and monitored at least once each
operating day to ensure proper operation. As with the control device standards,
monitoring requirements are given for certain types of control devices that are specified
in the regulations. Owners and operators using control devices other than those
specifically mentioned must develop documentation indicating proper operation and
maintenance of the control device and demonstrating that performance standards are
being met (§265.1033(i)).
If, at any time, inspection of the control device indicates that there is a problem with the
operation of the unit (i.e., failure to achieve the required organic destruction rate)
owners and operators must immediately implement corrective measures necessary to
return the control device to proper operation (§265.1033(f)(3)).
Closed-vent systems used to comply with Subpart A A must be monitored annually, or
more often if requested by the EPA Regional Administrator (§265.1033(1)). Any
detectable emissions must be controlled as soon as practicable, but not later than 15
calendar days after the emission is detected.
Recordkeeping and Reporting
The RCRA air emission standards are meant to be self-implementing. Consequently,
EPA does not play an active role in ensuring that facilities are in compliance with the
regulations on a day-to-day basis. Instead, the Agency verifies that owners and
operators are complying with the regulations through facility inspections and audits.
Subpart AA requires owners and operators to keep detailed records in the facility's
operating log to demonstrate compliance with the standards. Design documentation
and monitoring, operating, and inspection information for each unit subject to the
Subpart AA standards must be kept up-to-date and in the facility's operating log for at
least three years.
Subpart AA also requires that, every six months, owners and operators of permitted
facilities report to the Regional Administrator any instances during that time period
when a control device exceeded or operated outside of its design specifications (as
indicated by monitoring activities) for a period longer than 24 hours without being
corrected (§264.1036). The report must indicate the duration of each exceedance and
any corrective measures taken to remedy the situation. If during the six-month period
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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8 - Air Emissions
no exceedances occur at the facility, the owner and operator need not submit a report to
the Regional Administrator.
3.2 SUBPART BB
The following types of units are subject to the Subpart BB equipment leak standards:
•	Units subject to the permitting standards of Part 270 (i.e., permitted or interim
status)
•	Recycling units located at hazardous waste management facilities otherwise
subject to the permitting standards of Part 270 (i.e., independent of the recycling
unit, the facility already has a RCRA permit or is in interim status)
•	Less than 90-day large quantity generator units
Although most recycling units are exempt from regulation under RCRA, §261.6(d)
subjects certain recycling units to the Subpart BB standards. Thus, owners and
operators of recycling units located at facilities that already have a RCRA permit or are
operating in interim status must also comply with the applicable Subpart BB
regulations.
Like the Subpart AA standards, any unit exempt from the facility standards under
§§264/265.1 is not subject to the equipment leak standards of Subpart BB. For example,
a wastewater treatment unit that otherwise meets the applicability criteria of Subpart
BB is not subject to the standards, since the unit is exempt from Part 264/265
(§264.1 (g)(6), §265.1(c)(10)).
Figure 2 summarizes the applicability of the Subpart BB standards. Once the owner and
operator determine that a facility is subject to Subpart BB, they must consider additional
applicability criteria to determine whether the facility is subject to the air emission
control requirements.
Subpart BB establishes standards for equipment leaks at hazardous waste facilities by
requiring owners and operators to adopt safe management practices. These
requirements are not limited to those units regulated under Subpart AA, but encompass
all equipment used at any TSDF or LQG. EPA defines equipment as any valve, pump,
compressor, pressure relief device, sampling connection system, open-ended valve or
line, or flange or other connector, and any control device or system required by Subpart
AA (§264.1031). Owners and operators of equipment that contains or contacts
hazardous waste or hazardous waste residues with at least 10 percent organics by
weight are subject to the control requirements of Subpart BB (§265.1050). Equipment
that contains or contacts organic hazardous waste less than 300 hours per year are only
subject to the Subpart BB identification and recordkeeping requirements (§265.1050(f)).
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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Air Emissions - 9
Figure 2
SUBPART BB APPLICABILITY TREE
Is the unit:
Permitted or interim status?
Recycling unit at permitted/interim status facility?
Large quantity generator accumulating hazardous waste?
Yes^
Does the equipment meet the definition of
"equipment" in §264.1031?
Yes^
No
Is the equipment part of an exempt
waste unit under §§264/265,1?
No
Does the equipment come into contact with
hazardous waste with an organic concentration
of at least 10% by weight?
4
Yes
Subject to Subpart BB
No
Yes
No
Not subject to Subpart BB
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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10 - Air Emissions
Equipment Leak Control Requirements
The techniques used to control emissions from equipment leaks under Subpart BB
combine equipment standards with inspection and monitoring requirements to ensure
compliance with the standards. Specific requirements for each type of equipment are
given in the regulations. These requirements consist of design and operating standards
for each category of equipment. The standards also specify the type and frequency of
all inspection and monitoring activities required. All of these requirements vary
depending on the piece of equipment at the facility. For example, §265.1053 provides
the control standards for compressors. According to this section, each compressor must
be equipped with a seal system that includes a barrier fluid that will prevent organic
emissions from leaking to the atmosphere. Specifications are given in the regulations
for the compressor seal system and the standards each component must meet. In
addition, each barrier fluid must have a sensor that will detect failure of the system.
Owners and operators must also establish an inspection and monitoring program as
described below.
By requiring certain work practices to be established, EPA is able to ensure that owners
and operators are operating the equipment at the facility in a manner that will reduce or
eliminate the probability of an equipment leak. Subpart BB achieves this by requiring
owner and operators to establish specific leak detection and repair (LDAR) programs.
LDAR programs require leak detection monitoring and/or inspection by a specific
instrument, by visual means, or by sense of smell, depending on the type of equipment
being used at the facility. What constitutes a leak for purposes of Subpart BB will
depend on the type of equipment being used. For example, compressors are considered
leaking if the sensor (required by the design standards) indicates failure of the
compressor's seal system (§265.1053(f)).
Once a leak has been detected, repair must be initiated and completed within 15 days to
remain in compliance with the Subpart BB standards. As with the previous example,
the compressor standards may be used to illustrate LDAR program implementation.
Each sensor used on the compressor system must be checked daily to ensure that it is
functioning properly. If the sensor does indicate a leak, it must be repaired as soon as
practicable, but no later than 15 days after the leak was first detected (§265.1053(g)).
Recordkeeping and Reporting
The recordkeeping and reporting requirements for Subpart BB are very similar to those
in Subpart AA. Owners and operators must keep detailed records in the facility's
operating log sufficient to demonstrate compliance with the standards. Such
information includes design documentation and monitoring, operating, and inspection
information for each piece of equipment affected by Subpart BB. These records must be
kept up-to-date and in the facility's operating log for at least three years (§265.1064).
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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Air Emissions - 11
Subpart BB also requires that owners and operators of permitted facilities report to the
Regional Administrator every six months, indicating any instances during that time
period when the control device exceeded or operated outside of its design specifications
(as indicated by monitoring activities) for longer than 24 hours without being corrected
(§264.1065). The reports must indicate dates, duration, cause, and any corrective
measures that were taken to remedy the situation. If, during the six-month period, no
exceedances occur at the facility, the owner and operator need not submit any report to
the Regional Administrator.
As in Subpart A A, there are no reporting requirements for owners and operators of
interim status facilities, or for large quantity generators subject to Subpart BB.
3.3 SUBPART CC
The requirements of Subpart CC apply to owners and operators of TSDFs that treat,
store, or dispose of hazardous waste in tanks, surface impoundments, or containers
(§265.1080(a)). Subpart CC also applies to large quantity generators accumulating
waste in tanks and containers. Units exempt under §§264/265.1 are not subject to these
air emission control requirements. In addition, the following units are specifically
exempt from the air emissions control standards:
•	A waste management unit into which hazardous waste was placed before
December 6, 1996, as long as no hazardous waste is added to the units after
December 6,1996
•	A container with a capacity less than or equal to 0.1 m3 (approximately 26
gallons)
•	A tank or surface impoundment to which the owner and operator have stopped
adding hazardous waste and the owner and operator have begun implementing
or completed closure pursuant to an approved closure plan (with possible
exceptions for some surface impoundments)
•	A tank with process vent, as defined in §264.1031
•	A tank, surface impoundment, or container operating with controls in
compliance with a CAA standard under 40 CFR Parts 60-62.
In addition, the following units are presently deferred from regulation under Subpart
CC awaiting further study:
The information in this document is not by any means a complete representation of EPA's regulations or policies,
hut is an introduction to the topic used for Hotline training purposes.

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12 - Air Emissions
•	A waste management unit used solely to manage hazardous waste generated
under corrective action, CERCLA, or another federal or state remediation
authority
•	A waste management unit used solely to manage radioactive mixed waste.
Owners and operators of TSDFs that manage hazardous waste in tanks, surface
impoundments, and containers, as well as large quantity generators accumulating
hazardous waste in tanks and containers, must install air emission controls only if these
units manage waste that exceeds an average volatile organic concentration of 500
ppmw. Units managing wastes with organics that have been removed or destroyed
according to specific standards established in the regulations are not subject to these
control requirements. The Subpart CC standards outline specific procedures and
equations for making these determinations (§265.1084).
AIR EMISSION CONTROL REQUIREMENTS
Tanks, surface impoundments, and containers that manage hazardous waste exceeding
the 500 ppmw volatile organic concentration threshold must install air emission
controls that will prevent the release of organic constituents. For each unit, owners and
operators must install one of several control options offered in the Subpart CC
requirements.
Tanks
The Subpart CC regulations require owners and operators of TSDFs and LQGs to
control organic air emissions from tanks managing hazardous waste with an average
volatile organic concentration of greater than or equal to 500 ppmw. There are two
regulatory classes of tanks, Level 1 and I .evel 2. I .evel 1 tanks are those tanks that meet
maximum vapor pressure limits based on design capacity, are not heated above the
temperature at which the maximum vapor pressure was determined, and are not units
in which stabilization is conducted. Level 2 tanks are those tanks that either do not
meet the Level 1 tank criteria, or that the owner and operator have chosen to not
operate using Level 1 tank criteria.
A Level 1 tank must be operated with a fixed roof that forms a continuous barrier over
all hazardous waste stored in the tank. All openings in the fixed roof must be
connected to either a closure device or a closed-vent system connected to a control
device (§265.1085(c)).
Level 2 tanks have several different options for compliance with the Subpart CC
standards. They may be equipped with either a fixed roof and an internal floating roof,
an external floating roof, or a cover vented through a closed-vent system to a control
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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Air Emissions - 13
device. Level 2 tanks may also be pressure tanks that are operated in a closed system,
with no detectable emissions at any time. Finally, Level 2 tanks may be located inside a
permanent total enclosure that is vented through a closed-vent system to an enclosed
combustion device (§265.1085(d)).
Surface Impoundments
Owners and operators of surface impoundments subject to Subpart CC have two
regulatory compliance options. First, the owner or operator may install a cover (e.g., an
air-supported structure or a rigid cover) that is vented through a closed-vent system to
a control device. Specific design requirements for the cover, closed-vent system, and
control device are provided in the regulations. Second, the owner or operator may
install and operate a floating membrane cover. All openings in this cover must be
equipped with a closure device (§265.1086).
Containers
The Subpart CC regulations require owners and operators of TSDFs and LQGs to
control organic air emissions from containers managing hazardous waste with an
average volatile organic concentration of greater than or equal to 500 ppmw. There are
three regulatory categories of containers, Level 1, Level 2, and Level 3. Level 1
containers are all containers that have a design capacity between 0.1 m3 and 0.46 m3
(approximately 26 gallons and 119 gallons respectively), and containers with a design
capacity greater than 0.46 m3 that are not in light material service (§§265.1087(b)(l)(i)
and (ii)). Level 2 containers have a design capacity greater than 0.46 m3 and operate in
light material service (§265.1087(b)(l)(iii)). The third category, Level 3, consists of all
containers with a design capacity greater than 0.1 m3 that must remain uncovered for
waste stabilization (§265.1087(b)(2)), Containers with a design capacity less than or
equal to 0.1 m3 are exempt from Subpart CC regulation (§265.1080(b)(2)).
Level 1 containers have three compliance options under the Subpart CC regulations.
The first option is to meet all applicable Department of Transportation (DOT)
packaging requirements under 49 CFR Parts 173,178,179, and 180. The other Level 1
container compliance options are to employ a cover or other closure device, or to cover
the waste in the container with an organic-vapor suppressing barrier, such as a foam
(§265.1087(c)).
Level 2 containers may also meet DOT packaging standards in order to comply with the
Subpart CC air emission requirements. A second option is to demonstrate that the
container operates with no detectable organic emissions as determined by Method 21 of
Part 60, Appendix A. For a Level 2 container attached to a truck, trailer, or rail car, a
third option is to demonstrate, using Method 27 of Part 60, Appendix A, that the unit is
organic vapor-tight (§265.1087(d)).
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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14 - Air Emissions
Level 3 container emissions must be either vented directly through a closed-vent system
to a control device, or vented inside an enclosure through a closed-vent system to a
control device (§265.1087(e)).
CLOSED-VENT SYSTEMS AND CONTROL DEVICES
Under several of the control options for tanks, surface impoundments, and containers,
owners and operators are required to install a closed-vent system connected to a control
device in order to safely vent gases, fumes, and vapors emanating from the waste
management unit. As part of the unit-specific requirements, owners and operators
must comply with the standards for closed-vent systems and control devices in Part
264/265, Subpart AA.
INSPECTION AND MONITORING
Owners and operators of tanks, surface impoundments, and containers must visually
inspect and monitor each cover and cover opening, control-vent system, and control
device. The regulations provide for limited inspection requirements for certain types of
units operating under specific conditions. For some covers and control devices, owners
and operators must also demonstrate compliance with the air emissions standards
through specified test methods. All owners and operators subject to these requirements
must develop and implement a written plan and schedule detailing how all inspection
and monitoring activities will be implemented at their particular facility.
RECORDKEEPING AND REPORTING
Owners and operators managing hazardous waste in tanks, surface impoundments,
and containers must record and maintain documentation certifying that the tank covers,
floating membrane covers, container closures, closed-vent systems, and control devices
meet required design and operating standards (§265.1090). Owners and operators must
also maintain records of all tests used to comply with the air emissions standards, visual
inspections and monitoring, organic vapor determinations, and other documentation
demonstrating compliance with the Subpart CC standards.
Owners and operators of permitted units are required to report instances of
noncompliance with the tank, surface impoundment, container, and control device
standards to the EPA Regional Administrator (§264.1090), There are no reporting
requirements for owners and operators of interim status units, or for large quantity
generators.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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Air Emissions - 15
4. SPECIAL ISSUES
Several complex issues impact the applicability of the RCRA air emissions standards.
4.1 PERMIT AS A SHIELD
Most rulemakings do not require facilities with final permits to immediately comply
with regulations promulgated after final permit issuance. This provision is commonly
known as "permit-as-a-shield" (§270.4). On December 6,1994, EPA amended §270.4 to
require that owners and operators of TSDFs that have been issued final permits prior to
October 6,1996, comply with the air emission standards under Part 265, Subparts AA,
BB, and CC, until the facility's permit is reviewed, reissued, or a class 3 permit
modification is conducted (59 FR 62896, 62920).
4.2 INTERFACE WITH CLEAN AIR ACT
Although the control of air emissions is typically an issue addressed under CAA, RCRA
§3004(n) gives EPA the specific authority to address air emissions from hazardous
waste management sources under RCRA. The RCRA air emission standards are
designed to complement, rather than duplicate, regulations under the CAA. Although
it is possible for facilities to be subject to both the CAA and the RCRA air emission
standards, RCRA § 1006(b) directs EPA to coordinate all provisions of RCRA with the
appropriate provisions of other environmental laws. In order to prevent regulatory
duplication, EPA will, to the maximum extent practicable, consider all other
environmental laws when promulgating regulations under both CAA and RCRA. One
example of this was the addition of the Subpart CC exemption for facilities operating
controls in compliance with a CAA standard (§265.1080(b)(7)).
4.3 APPLICABILITY OF SUBPARTS AA AND BB TO LARGE
QUANTITY GENERATORS
Prior to promulgation of Subpart CC, large quantity generators were not subject to
existing air emission standards for process vents and equipment leaks under Subparts
A A and BB. Given the significant organic emissions from tanks and containers used for
hazardous waste accumulation at these facilities, EPA determined that it was necessary
to subject large quantity generators to all of the RCRA air emission standards. As a
result, when the Subpart CC standards were promulgated on December 6,1994, the
Agency amended §262.34 to add a requirement that large quantity generators
accumulating hazardous waste in tanks and containers also comply with the air
emission standards of Subparts A A, BB and CC. The rule makes this provision a
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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16 - Air Emissions
condition that large quantity generators must comply with to maintain permit-exempt
status under RCRA.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.

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