AEPA

www.epa.gov/hwpermittina

EPA 530-F-22-007
December 2022

RCRA Organic Air Emission Standards for
TSDFs and Large Quantity Generators

Introduction

Section 3004(11) of the Resource Conservation and Recovery Act
(RCRA) requires the development of standards to monitor and
control air emissions from hazardous waste treatment, storage, and
disposal facilities (TSDFs) as necessary to protect human health and
the environment. To implement this, EPA established the RCRA
Organic Air Emission Standards under three subparts found in Title
40 of the Code of the Federal Regulations (CFR), part 264
(permitted facilities) and part 265 (interim status facilities). These
standards are applicable to hazardous waste TSDFs and certain
large quantity generators (LQGs). They establish performance,
design, operation, monitoring, recordkeeping, and maintenance
requirements for certain hazardous waste management units
(HWMUs) and associated equipment and air emission control
devices. Specifically, Subpart AA controls air emissionsfrom certain
process vents, Subpart BB controls air emissions from specified
equipment leaks, and Subpart CC controls air emissionsfrom
certain tanks, containers, surface impoundments and miscellaneous
units as applicable. This document provides a high-level overview of
those standards, including applicability and requirements, for
TSDFs and LQGs.1

Subpart AA - Air Emissions Standards for
Process Vents

" The Subpart AA standards require air emission controls for
process vents associated with distillation, fractionation, thin-film
evaporation, solvent extraction, or air or steam stripping
operations that manage hazardous wastes with organic
concentrations of at least 10 parts per million by weight (ppmw)
if these operations are conducted in the following types of
units2:

Why is it Important to Regulate
Air Emissions?

Emissions from hazardous waste management
units include toxic organic compounds and
ozone precursors. These can result in exposure
to onsite workers and impact nearby
communities. Adverse health effects such as
cancer, and environmental effects such as crop
damage, may result from exposure to these
organic emissions. Organic airemissions can
also increase the risk of fire or explosion.

Applicability of the RCRA
Organic Air Emission Standards
to Recycling Units

Although units engaged in legitimate recycling
of hazardous waste can be conditionally
exempt from permitting under RCRA, 40 CFR
section 261.6(d) subjects certain recycling units
to the Subpart AA and BB standards. Recycling
units at facilities that are subject to RCRA
permitting for storage, or are operating in
interim status, must also comply with the
applicable Subpart AA and BB regulations.
Subpart CC does not apply to recycling units
because the emission mechanisms for
hazardous waste storage tanks differ
significantly from the emission mechanisms of
the distillation-type units used for recycling and
certain treatment operations (e.g., air strippers
and thin-film evaporators), which are regulated
under subpart AA. (Referto 61 Fed. Reg.
59/935, Nov. 25,1996).

1 The contents of this fact sheet do not have the force and effect of law. This fact sheet is intended only to provide clarity to the public
about existing requirements underthe law and Agency policies.

2Referto 40 CFR sections 26a. 1030 or 26c;.10m


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2

Example of a chemical plant distillation tower. Certain
process vents associated with distillation and other
processes that manage hazardous waste may be subject
to Subpart AA.

—	Units subject to the permitting standards of
40 CFR part 270 (i.e.. permitted or interim
status). Refer to 40 CFR sections 264003c or
2650030.

—	Hazardous waste recycling units located at.
hazardous waste management facilities that
store hazardous waste prior to recycling or
are otherwise subject to the permitting
requirements of 40 CFR part 270 (i.e., the
facility has a RCRA permit or is in interim
status).3 Refer to 40 CFR sections 26^1030
or 2650030.

—	"90-day" accumulation tanks or containers
at LQGs (refer to ,0 CFR section 262.17(a).
formerly section 262.34(a), and 40 CFR
sections 26^0030 or 2650030).

¦	According to 40 CFR section 26^.601. certain
Subpart X miscellaneous units may also be subject
to Subpart AA requirements, as appropriate, to
control volatile organic emissionsfrom the unit.

¦	Refer to 40 CFR sections 26^1030 through
26^0036 or 40 CFR sections 2650030 through
2650035,for all of the air emission standards and
related requirements for process vents, closed-
vent systems, and control devices.

3 Hazardous waste recycling units at facilities that do not store
hazardous waste priorto recycling and are not otherwise subject
to the permitting requirements of 40 CFR Part 270 are not subject
to the Subpart AA standards.

¦	Exemption provision. The provisions of 40 CFR
26&oo3o(e) and 26c;oo3o(d exempt all process
vents subject to Subpart AA that the facility
owner or operator certifies are "equipped with
and operating air emission controls in accordance
with the . . . requirements of an applicable Clean
Air Act regulation codified under 40 CFR part 60,
part 61, or part 63."4

Air Emission Control Requirements

Facilities subject to Subpart AA must meet one of the
following conditions presented in the regulations to
reduce and/or destroy the organics in the waste stream:
(Refer to 40 CFR section 264.1032(a) or section

2650032(a)).

¦	Reduction of organic air emissions from all
affected process vents at the facility to below 3.0
pounds per hour (1.4 kg/h) and 3.1 tons per year
(2.8 Mg/yr).

OR

" Reduction of organic air emissions from all

affected process vents at the facility by 95 percent
by weight through the installation and operation
of a control device.

Facilities must also comply with the test methods and
procedures, monitoring, recordkeeping, and reporting
requirements applicable to the affected units.

Control Devices and Closed-Vent System

¦	Control devices include vapor recovery systems,
enclosed combustion devices, and flares (refer to
40 CFR sections 264.1033 (b), (c) and (d); or
sections 2650033(b), (c) and (d)). Owners and
operators may use other types of control devices
as long as the emission reduction requirements of
40 CFR section 26/1.1032.(3) or section 265.1032(a)
are met.

¦	Closed-vent systems may also be installed to
channel or route organicsto the control device.

Inspection and Monitoring

¦	Control devices used to comply with Subpart AA
must be monitored by installing, calibrating, and
operating a flow indicator and a continuous

4 For more information on the implementation of the Subpart AA
compliance exemption provision, refer to the "Implementing the

RCRA/CAA Air Emission Controls Compliance Exemption/Election
Provisions Through RCRA Permits" document (EPA 530-R-19-006).


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monitoring device such as, depending on the type
of control device in use, a temperature
monitoring, heat sensing monitoring, or organic
compounds level monitoring device, following
the requirements in 40 CFR section 264.1033(f) or
section 265.1033(f). Readings from each
monitoring device are required to be inspected at
least once each operating day. Should
exceedances occur, facilities must immediately
implement corrective measures.

¦	Closed-vent systems used to comply with
Subpart AA must be monitored at least annually.
Any detectable emissions must be controlled as
soon as possible, but typically not later than 15
calendar days after the emission is detected (40
CFR section 264.1033(1) or section 265.iQ33(k)).

Recordkeeping

¦	The Subpart AA recordkeeping requirements in
40 CFR section 264.1035 or section 265^1035
include maintaining certain information in the
facility record, such as:

—	A performance test plan for facilities using
test data to determine the organic removal
efficiency or total organic compound
concentration achieved by the control
device.

—	Design documentation and monitoring,
operating, and inspection information for
each closed-vent system and control device
required to comply with the provisions of
Subpart AA.

¦	Recordkeeping requirements also include up-to-
date documentation of compliance with the
process vent standards in 40 CFR sections
264.1032. or section 265.1032. such as:

—	Information and data identifying all affected
process vents, annual throughput and
operating hours of each affected unit;
estimated emission rates for each affected
vent and for the overall facility (i.e., the total
emissions for all affected vents at the
facility); and the approximate location
within the facility of each affected unit (e.g.,
identify the HWMUs on a facility plot plan).

— Information and data supporting
determinations of vent emissions and
emission reductions achieved by add-on
control devices based on engineering
calculations or source tests.

Documentation of compliance with the process
vent standards is also required for the RCRA
permitting decision and must be included in the
RCRA permit application (40 CFR section 270.2.4).

For process ventsthat are equipped with and
operating air emission controls in accordance with
the requirements of an applicable Clean Air Act
(CAA) regulation codified under 40 CFR part 60,
part 61, or part 63, the owner or operator is still
required to maintain with the facility operating
record documentation demonstrating compliance
under regulations at 40 CFR part 60, part 61, or part
^available (referto 40 CFR section 264.1030(e) or
section 265.1030(d)).

Example of a process vent with valve at the bottom.

Reporting

¦ Subpart AA requires that owners and operators of
permitted facilities report to the Regional
Administrator every six months, indicating, among
other things, the dates when the control device
exceeded or operated outside the design
specifications5 without being corrected within 24
hours; the duration and cause of each exceedance

5 As defined in 40 CFR section 264.1035(c)(4) and as indicated by
the control device monitoring required by 40 CFR section

264.1033(f).


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or visible emissions; and any corrective measures
taken (40 CFR section 26^1036).

¦	There are no Subpart AA reporting requirements for
owners and operators of interim status facilities or
for LQGs.

Subpart BB - Air Emissions
Standards for Equipment Leaks

¦	The Subpart BB standards apply to certain
equipment, such as pumps, compressors, pressure-
relief devices, sampling connection systems, and
valves, that contains or contacts hazardous wastes
with organic concentrations of at least 10 percent
by weight if they are managed at the following
types of units:

—	Units subject to the permitting requirements
of 40 CFR part 270 (i.e.. permitted or interim
status). Refer to 40 CFR sections 264.1050 or

265.1050.

—	Hazardous waste recycling units located at
hazardous waste management facilities that
store hazardous waste prior to recycling or
are otherwise subject to the permitting
requirements of 40 CFR part 270 (i.e., the
facility has a RCRA permit or is in interim
status).6 Refer to 40 CFR sections 264.1050
or 265.1050.

—	"90-day" accumulation tanks or containers
at LQGs (40 CFR section 262.17(a). formerly
section 262.34(a), and 40 CFR sections
264.1050 or 265.1050).

¦	According to 40 CFR section 264.601. certain
Subpart X miscellaneous units may also be subject
to Subpart BB requirements, as appropriate, to
control volatile organic emissionsfrom the
equipment.

¦	Subpart BB requires organic air emission controls
for equipment leaks. The requirements vary
depending on the type of equipment in use (e.g.,
pressure-relief devices in gas/vapor service,
sampling connection systems).

¦	If the equipment contains or contacts hazardous

6 Hazardous waste recycling units at facilities that do not store
hazardous waste priorto recycling and are not otherwise subject
to the permitting requirements of 40 CFR Part 270 are not subject
to the Subpart BB standards.

waste or hazardous waste residues for less than 300
hours per calendar year, or if the equipment is in
vacuum service, it is excluded from the
requirements of 40 CFR sections 264.1052 to
264.1060. or 40 CFR sections 265.1050 to 265.1060.
if it is identified as required in 40 CFR sections
264.1064(g)(5). 264.1064(g)(6). 265.1064(g)(5) or
265.1064(g)(6). However, that same equipment is
not excluded from Subpart BB
identification/marking, recordkeeping, and
reporting (refer to 40 CFR sections 264.1050(d)
through 264.1050(f). or 40 CFR sections 265.1050(c)
through 265.1050(e)).

¦	For all of the air emission standards and related
requirements for equipment leaks, refer to 40 CFR
sections 264.1050 through 264.1065. or 40 CFR
sections 265.1050 through 265.1064.

¦	Compliance election provision. Subpart BB allows
owners or operators to elect to demonstrate
compliance with Subpart BB either via 40 CFR
sections 264.1064 or 265.1064 or by
documentation of compliance with an applicable
CAA regulation codified under 40 CFR part 60, part
61. or part 63. A facility choosing compliance
election continues to be subject to Subpart BB,
which means the RCRA program still addresses
Subpart BB in the permit (for TSDFs), and
determines compliance by evaluating the CAA
records that the owner or operator elects to
maintain under 40 CFR 264.1064(171) or
265.1064(171) (for both TSDFs and LQGs).7

Inspection and Monitoring

¦	Each piece of equipment that is subject to the
Subpart BB standards must be marked so that it
can be readily distinguished from other pieces of
equipment, specifically tracked in the facility
operating records and reflected in the RCRA permit
application (40 CFR section 264.1050(d). and
section 265.1050(c)).

¦	The equipment must be monitored and inspected
regularly. Equipment-specific inspection,
monitoring, and repair requirements are contained
in 40 CFR sections 264.1052 through 264.1060. and

7 For more information on the implementation of the Subpart BB
compliance election provision, referto the "Implementing the
RCRA/CAA Air Emission Controls Compliance Exemption/Election
Provisions Through RCRA Permits" document (EPA 530-R-19-006).


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40 CFR sections 265.1052 through 265.1060.

¦ Most equipment leaks must be repaired no later
than 15 calendar days after they are detected

(e.g., 40 CFR section 264. 1052(c)(1) or section
265.1052(c)(1)). However, a pressure-relief device
in gas/vapor service must be returned to a
condition of no detectable emissions no later
than five calendar days after a pressure release
(40 CFR section 264.1054 or section 265.1054(b)).

JfL If

Recordkeeping

¦	Subpart BB recordkeeping requirements include:
equipment identification number; type of
equipment; approximate location within the
facility, and methods of compliance monitoring
(e.g., leak detection and repair (LDAR) program)8.
When equipment leaks are detected, certain
information must be recorded and kept in the
facility operating record for at least three years.

Refer to 40 CFR section 264.1064 or section
265.1061 for more specific recordkeeping
requirements.

" Written LDAR programs, identification and
tracking systems, equipment-specific monitoring
and inspections systems, and training plans for
employees are also required for the RCRA
permitting decision and must be included in the
RCRA permit, application (40 CFR sections 270.14
or section 270.25).

¦	Owners or operators electing to determine
compliance by documentation in accordance with
an applicable CAA regulation codified under 40
CFR part 60, part 61, or part 63, are required to

keep such documentation, or make it readily
available with the facility operating record (40 CFR
sections 264.1064(1x1) or section 265.1064(111)).

Reporting

¦	Subpart BB requires that owners and operators of
permitted facilities report to the Regional
Administrator every six months, indicating any
instances during that period when a leaking valve,
pump, or compressor was not repaired (as required
by BB), and when a control device exceeded
specifications (as indicated by monitoring
activities) for longerthan 24 hours without being
corrected (40 CFR section 264.1065). The reports
must indicate dates, duration times, causes, and
any corrective measures that were taken with
respect to control devices. If, during the six-month
period, no exceedances occur and all leaks are
repaired at the facility, the owner and operator
need not submit a report to the Regional
Administrator.

¦	As in Subpart AA, there are no Subpart BB
reporting requirements for owners and operators
of interim status facilities or for LQGs.

Subpart CC - Air Emission Standards
for Tanks, Surface Impoundments,
and Containers

¦	The Subpart CC standards apply to owners and
operators of facilities that treat., store, or dispose
of hazardous waste in certain tanks, surface
impoundments, or containers subject to 40 CFR
parts 264 or 265 subparts I, J, or K. This includes
LQGs (e.g., generators of 1,000 kg/month or more
of non-acute hazardous waste) accumulating
hazardous waste in tanks or containers for up to 90
days (40 CFR section 262.17(a). formerly section
262.34(a)).

¦	Additionally, according to 40 CFR section 264.601.
Subpart X miscellaneous units are subject to
Subpart CC requirements, as appropriate, to
control volatile organic emissions from the units
(e.g., drum shredders).

¦	Refer to 40 CFR section 264.1080 or section
2.65.1080 to determine if your waste management

3 For more information about LDAR programs, read the "Leak

Detection and Repair: A Best Practices Guide."


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units are subject to the Subpart CC regulations.

¦	Subpart CC requires owners or operators to
manage wastes in units that are closed such that
emissions do not escape or are controlled,

" Generally, if a hazardous waste has an average
volatile organic concentration of less than 500
parts per million by weight (ppmw) at the point of
waste origination, or if the hazardous waste's
organic content has been reduced to the extent
described in 40 CFR section 264.1082(c)(2) or
section 265.1083(c)(2) prior to entering the waste
management unit, the unit is exempt from the air
emission controls required under 40 CFR sections
264.108/,. through 264.1087 or sections 265.1085
through 265.1088. Refer to 40 CFR section
264.1082(c) or section 265.1083(c).

¦	The procedures to be used for determining average
volatile organic concentration and other waste
characteristics are specified in 40 CFR section

264.1083 or section 265.1084.

¦	Refer to 40 CFR sections 264.1080 through
264.10Q0 or 40 CFR sections 265.1080 through
265.10Q0 for all of the air emission standards and
related requirements for tanks, surface
impoundments and containers.

¦	Exemption provision. The provisions of 40 CFR
264.io8o(b)f~/ and 265.io8o(b)(7 exempt all
hazardous waste management units subject to
Subpart CC that the facility owner or operator
certifies are "equipped with and operating air
emission controls in accordance with the . . .
requirements of an applicable Clean Air Act.
regulation codified under 40 CFR part 6o. part 61.
or part 63."9

Unit-Specific Requirements

¦	Subpart CC standards applicable to tanks
containing hazardous wastes are specified in 40
CFR section 264.1084 and section 265.1085. For
example, all tanks subject to the Subpart CC
standards must be regularly inspected. Inspection
procedures and requirements vary by type of tank
control used. Records of ail inspections, regardless
of the control level, must be kept at the facility for
a minimum of three years after the date of the

inspection (refer to 40 CFR section 264.io8g(a) or

Example of a stainless-steel fuel tank with closure device

secured in the closed position so that emissions are controlled.

section 265.ioqo(a)). There are two levels of air
emission controls for tanks which are determined
based on the size of the tank, maximum organic
vapor pressure of the waste, and whether the tank
is used in a waste stabilization process. Table 1
provides a matrixfor determining the applicable
level of control for tanks.

¦	Subpart CC standards applicable to surface
impoundments containing hazardous wastes are
found in 40 CFR section 264.1085 and section
2.65.1086. For example, an owner or operator must
install and operate either a floating membrane
cover or a cover that is vented through a closed-
vent system to a control device. The floating
membrane cover must meet certain design
requirements specified in the rule.

¦	Subpart CC standards applicable to containers of
hazardous wastes are specified in 40 CFR section
264.1086 and section 265.1087. For example, if a
Level 1 or 2 container is not going to be emptied
within 24 hours after it is accepted at the facility, a
visual inspection is required on or before the date
the container is accepted and at least once a year
thereafter. Repairs of defects in such containers
must be completed within five days or the contents
of the container must be removed from the

9 For more information on the implementation of the Subpart AA
compliance exemption provision, read the "Implementing the

RCRA/CAA Air Emission Controls Compliance Exemption/Election
Provisions Through RCRA Permits" document (EPA 530-R-19-006).


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7

container (40 CFR sections 264.io86(c)u and
264.10861'd'K ; and 40 CFR sections 265.1087(c)(4)
and 265.1087(d)(4)). There are three levels of air
emission controls for containers based on container
size, light material service (which is determined by
the vapor pressure of the organic constituents), and
whether the container is used in a waste
stabilization process. Table 2 provides a matrix for
determining the applicable control level for a

Example of a pressure relief valve located on a tank.
container.

Inspection and Monitoring

¦ Owners or operators are required to develop and
implement a written plan and schedule to perform
the inspections and monitoring of the air emission
control equipment that is required in 40 CFR
sections 264.1084 through 264.1087 for permitted
facilities, or 40 CFR sections 265.108c; through
265.1088 for interim status facilities and LQGs.
Requirements vary by the type of waste
management unit and the type of air emission
controls used (40 CFR section 264.1088 and section
26q.io8g).

Recordkeeping

" Each owner or operator of a facility subject to
Subpart CC must comply with the recordkeeping
requirements found in 40 CFR section 264.108Q or
section 265..10Q0. including documentation specific
to the type of unit and air emissions control being
used. For each tank using air emission controls the
requirements include an identification number, a
record of each inspection including location,
description, date of detection, and corrective

action for each defect detected.

¦	In the event that repair of the defect is delayed, the
reason for delay and expected completion of repair
date must also be recorded.

¦	For HWMUsthat are equipped with and operating
air emission controls in accordance with the
requirements of an applicable Clean Air Act
regulation codified under 40 CFR part 60, part 61,
or part 63 (refer to 40 CFR section 264.1080(b)(7)
and section 265.1080(b)(7)). the owner or operator
is still required to maintain recordsthat document
the rationale for the exemption (40 CFR section
264.108Q; and section 265.ioqo(i).

Reporting

¦	Subpart CC requires owners or operators of
permitted facilities to submit a written report
within 15 calendar days of the time that the owner
or operator becomes aware of a noncompliance
occurrence with the conditions specified in:

—	40 CFR section 264.1082(c). as applicable,
for tanks, surface impoundments or
containers exempted from using air
emission controls under that provision (40
CFR section 264.ioqo(a)),

-	40 CFR section 264.1084(b). as applicable,
for tanks using air emission controls in
accordance with that provision ( 40 CFR
section 264.ioqo(b)).

¦	Owners or operators of a permitted facility using a
control device in accordance with the requirements
of 40 CFR section 264.1087 shall submit a
semiannual written report as applicable. (40 CFR
sections 264.iogo(c) and (d)).

¦	There are no Subpart CC reporting requirements
for owners and operators of interim status facilities
or for LQGs.


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8

Table 1. Determination of Applicable Level of Control forTanks Containing
Hazardous Waste Subject to the Subpart CC Regulations

Tank Design Capacity

Maximum Organic Vapor
Pressure of Hazardous
Waste in Tank

Does Waste Stabilization
Process Occur in the
Tank?

Applicable Level of
Control

<75 m3 (19,800 gal)

< 76.6 kPa (11.1 psi)

Yes

Tank Level 2 Controls

<75 m3 (19,800 gal)

< 76.6 kPa (11.1 psi)

No

Tank Level 1 Controls

<75 m3 (19,800 gal)

> 76.6 kPa

Yes

Tank Level 2 Controls

<75 m3 (19,800 gal)

> 76.6 kPa

No

Tank Level 2 Controls

> 75 IT13 (19,800 gal) and < 151
m3(39,900 gal)

< 27.6 kPa (4.0 psi)

Yes

Tank Level 2 Controls

> 75 m3 (19,800 gal) and < 151
m3(39,900 gal)

< 27.6 kPa (4.0 psi)

No

Tank Level 1 Controls

> 75 m3 (19,800 gal) and < 151
m3(39,900 gal)

> 27.6 kPa

Yes

Tank Level 2 Controls

> 75 m3 (19,800 gal) and < 151
m3(39,900 gal)

> 27.6 kPa

No

Tank Level 2 Controls

> 151 m3 (39,000 gal)

< 5.2 kPa (0.75 psi)

Yes

Tank Level 2 Controls

> 151 m3 (39,000 gal)

< 5.2 kPa (0.75 psi)

No

Tank Level 1 Controls

> 151 m3 (39,000 gal)

> 5.2 kPa

Yes

Tank Level 2 Controls

> 151 m3 (39,000 gal)

> 5.2 kPa

No

Tank Level 2 Controls


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Table 2. Determination of Applicable Level of Control for Containers of Hazardous

Waste Subject to the Subpart CC Regulations

Container Design
Capacity

Is the Container in Light
Material Service?10

Does Waste Stabilization
Process Occur in the
Container?

Applicable Level of
Control

< 0.1 IT13 (26.4 gal)

NA

NA

Container is Exempt from Air
Emission Standards

> 0.1 IT13 (26.4 gal) and
< 0.46 IT13 (121 gal)

Yes

Yes

Container Level 3 Controls

> 0.1 IT13 (26.4 gal) and
< 0.46 IT13 (121 gal)

No

No

Container Level 1 Controls

> 0.1 IT13 (26.4 gal) and
< 0.46 IT13 (121 gal)

No

Yes

Container Level 3 Controls

> 0.1 IT13 (26.4 gal) and
< 0.46 IT13 (121 gal)

Yes

No

Container Level 1 Controls

> 0.46 IT13 (121 gal)

Yes

Yes

Container Level 3 Controls

> 0.46 IT13 (121 gal)

No

No

Container Level 1 Controls

> 0.46 IT13 (121 gal)

No

Yes

Container Level 3 Controls

> 0.46 IT13 (121 gal)

Yes

No

Container Level 2 Controls

function of which is the recovery or capture of solvents
or other organics for use, reuse, or sale is not a control
device (40 CFR section 264.1031).

Equipment - Each valve, pump, compressor, pressure
relief device, sampling connection system, open-ended
valve or line, or flange or other connector, and any
other control devices or systems required by part 264
and part 265, of Subpart AA (40 CFR section 264.1031).

Enclosure - A structure that surrounds a tank or
container, captures organic vapors emitted from the
tank or container, and vents the captured vapors
through a closed vent system to a control device (40
CFR section 265.1081).

Hazardous waste management unit (HWMU) - A

contiguous area of land on or in which hazardous waste
is placed, orthe largest area in which there is
significant likelihood of mixing hazardous waste
constituents in the same area. Examples of hazardous

Definitions

Average volatile organic concentration - The mass-
weighted average volatile organic concentration of a
hazardous waste as determined in accordance with the
requirements of 40 CFR section 265.1084(3) (40 CFR
section 265.1081).

Closed-vent system - A system that is not open to the
atmosphere and that is composed of piping,
connections, and, if necessary, flow-inducing devices
that transport gas or vapor from a piece or pieces of
equipment to a control device (40 CFR section
264.1031).

Container- Any portable device in which a material is
stored, transported, treated, disposed of, or otherwise
handled (40 CFR section 260.10).

Control device - An enclosed combustion device,
vapor recovery system, or flare. Any device the primary

10 The vapor pressure of one or more of the organic constituents in the material is greater than 0.3 kilopascals (kPa) at 20°C; and the total
concentration of the pure organic constituents having a vapor pressure greater than 0.3 kPa at 20°C is equal to or greater than 20 percent
by weight.


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waste management units include a surface
impoundment, a waste pile, a land treatment area, a
landfill cell, an incinerator, a tank and its associated
piping and underlying containment system and a
container storage area. A container alone does not
constitute a unit; the unit includes containers and the
land or pad upon which they are placed (40 CFR section
260.10).

In light material service - A container that is used to
manage a material for which both of the following
conditions apply: (1) the vapor pressure of one or more
of the organic constituents in the material is greater
than 0.3 kilopascals (kPa) at 20°C; and (2) the total
concentration of the pure organic constituents having a
vapor pressure greater than 0.3 kPa at 20°C is equal to
or greater than 20 percent by weight (40 CFR section
265.1081).

In vacuum service - Equipment that is operating at an
internal pressure that is at least 5 kPa below ambient
pressure (40 CFR section 264.1031).

Large Quantity Generator (LQG) - A generator who
generates any of the following amounts in a calendar
month: (1) Greater than or equal to 1,000 kilograms
(2200 lbs) of non-acute hazardous waste; or (2) Greater
than 1 kilogram (2.2 lbs) of acute hazardous waste
listed in 40 CFR section 261.31 or section 261.33(e); or
(3) Greater than 100 kilograms (220 lbs) of any residue
or contaminated soil, water, or other debris resulting
from the cleanup of a spill, into or on any land or water,
of any acute hazardous waste listed in 40 CFR section
261.31 or section 261.33(e) (40 CFR section 260.10).

Maximum organic vapor pressure - The sum of the

individual organic constituent partial pressures exerted
by the material contained in a tank, at the maximum
vapor-pressure-causing conditions (e.g., temperature,
agitation, pH effects of combining wastes) reasonably
expected to occur in the tank. Maximum organic vapor
pressure is determined using the procedures specified
in 40 CFR section 265.1084(c) (40 CFR section
265.1081).

Miscellaneous unit-A hazardous waste management
unit where hazardous waste is treated, stored, or
disposed of and that is not a container, tank, surface
impoundment, pile, land treatment unit, landfill,
incinerator, boiler, industrial furnace, underground
injection well with appropriate technical standards
under 40 CFR part 146. containment building,

corrective action management unit, unit eligible for a
research, development, and demonstration permit
under 40 CFR section 270.65. or staging pile (40 CFR
section 260.10).

No detectable organic emissions - No escape of
organics to the atmosphere as determined using the
procedures specified in 40 CFR section 265.1084(d) (40
CFR section 265.1081).

Point of waste origination - (1) When the facility
owner or operator is the generator of the hazardous
waste, the point of waste origination means the point
where a solid waste produced by a system, process, or
waste management unit is determined to be a
hazardous waste as defined in 40 CFR section 261. (2)
When the facility owner or operator is not the
generator of the hazardous waste, point of waste
origination meansthe point where the owner or
operator accepts delivery or takes possession of the
hazardous waste (40 CFR section 265.1081).

Process vent - Any open-ended pipe or stack that is
vented to the atmosphere either directly, through a
vacuum-producing system, or through a tank (e.g.,
distillate receiver, condenser, bottoms receiver, surge
control tank, separator tank, or hot well) associated
with hazardous waste distillation, fractionation, thin-
film evaporation, solvent extraction, or air or steam
stripping operations (40 CFR section 264.1031).

Surface impoundment or impoundment - A facility or
part of a facility which is a natural topographic
depression, man-made excavation, or diked area
formed primarily of earthen materials (although it may
be lined with man-made materials), which is designed
to hold an accumulation of liquid wastes or wastes
containing free liquids, and which is not an injection
well. Examples of surface impoundments are holding,
storage, settling, and aeration pits, ponds, and lagoons
(40 CFR section 260.10).

Tank - A stationary device designed to contain an
accumulation of hazardous waste, which is constructed
primarily of non-earthen materials that provide
structural support (40 CFR section 260.10).

Volatile organic concentration - The fraction by
weight of the volatile organic compounds contained in
a hazardous waste expressed in terms of parts per
million (ppmw) as determined by direct measurement
or by knowledge of the waste in accordance with the
requirements of 40 CFR section 265.1084. For the


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purpose of determining the volatile organic
concentration of a hazardous waste, organic
compounds with a Henry's law constant value of at
least o.i mole-fraction-in-the-gas-phase/mole-fraction-
in the liquid-phase (o.i Y/X) (which can also be
expressed as 1.8 x 10"6 atmospheres/gram-mole/m3) at
25 degrees Celsius must be included. 40 CFR Part 265
Appendix VI presents a list of compounds known to
have a Henry's law constant value less than the cutoff
level (40 CFR section 265.1081).

Waste stabilization process - Any physical or chemical
process used to either reduce the mobility of hazardous
constituents in a hazardous waste or eliminate free
liquids as determined by Test Method 9095 (Paint Filter
Liquids Test) in "Test Methods for Evaluating Solid
Waste, Physical/Chemical Methods," EPA Publication
No. SW-846, third edition, September 1986, as
incorporated by reference in 40 CFR section 260.11. A
waste stabilization process involves mixing the
hazardous waste with binders or other materials, and
curing the resulting hazardous waste and binder
mixture. Other synonymous terms used to refer to this
process are "waste fixation" or "waste solidification."
This does not include the adding of absorbent materials
to the surface of a waste, without mixing, agitation, or
subsequent curing, to absorb free liquid (40 CFR
section 265.1081).


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