[Code of Federal Regulations]
[Title 40, Volume 24]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR264.1084]

[Page 418-427]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 264_STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, 
STORAGE, AND DISPOSAL FACILITIES--Table of Contents
 
 Subpart CC_Air Emission Standards for Tanks, Surface Impoundments, and 
                               Containers
 
Sec. 264.1084  Standards: Tanks.

    (a) The provisions of this section apply to the control of air 
pollutant emissions from tanks for which Sec. 264.1082(b) of this 
subpart references the use of this section for such air emission 
control.
    (b) The owner or operator shall control air pollutant emissions from 
each tank subject to this section in accordance with the following 
requirements as applicable:
    (1) For a tank that manages hazardous waste that meets all of the 
conditions specified in paragraphs (b)(1)(i) through (b)(1)(iii) of this 
section, the owner or operator shall control air pollutant emissions 
from the tank in accordance with the Tank Level 1 controls specified in 
paragraph (c) of this section or the Tank Level 2 controls specified in 
paragraph (d) of this section.
    (i) The hazardous waste in the tank has a maximum organic vapor 
pressure which is less than the maximum organic vapor pressure limit for 
the tank's design capacity category as follows:
    (A) For a tank design capacity equal to or greater than 151 m\3\, 
the maximum organic vapor pressure limit for the tank is 5.2 kPa.
    (B) For a tank design capacity equal to or greater than 75 m\3\ but 
less than 151 m\3\, the maximum organic vapor pressure limit for the 
tank is 27.6 kPa.
    (C) For a tank design capacity less than 75 m\3\, the maximum 
organic vapor pressure limit for the tank is 76.6 kPa.
    (ii) The hazardous waste in the tank is not heated by the owner or 
operator to a temperature that is greater than the temperature at which 
the maximum organic vapor pressure of the hazardous waste is determined 
for the purpose of complying with paragraph (b)(1)(i) of this section.
    (iii) The hazardous waste in the tank is not treated by the owner or 
operator using a waste stabilization process, as defined in 40 CFR 
265.1081.

[[Page 419]]

    (2) For a tank that manages hazardous waste that does not meet all 
of the conditions specified in paragraphs (b)(1)(i) through (b)(1)(iii) 
of this section, the owner or operator shall control air pollutant 
emissions from the tank by using Tank Level 2 controls in accordance 
with the requirements of paragraph (d) of this section. Examples of 
tanks required to use Tank Level 2 controls include: A tank used for a 
waste stabilization process; and a tank for which the hazardous waste in 
the tank has a maximum organic vapor pressure that is equal to or 
greater than the maximum organic vapor pressure limit for the tank's 
design capacity category as specified in paragraph (b)(1)(i) of this 
section.
    (c) Owners and operators controlling air pollutant emissions from a 
tank using Tank Level 1 controls shall meet the requirements specified 
in paragraphs (c)(1) through (c)(4) of this section:
    (1) The owner or operator shall determine the maximum organic vapor 
pressure for a hazardous waste to be managed in the tank using Tank 
Level 1 controls before the first time the hazardous waste is placed in 
the tank. The maximum organic vapor pressure shall be determined using 
the procedures specified in Sec. 264.1083(c) of this subpart. 
Thereafter, the owner or operator shall perform a new determination 
whenever changes to the hazardous waste managed in the tank could 
potentially cause the maximum organic vapor pressure to increase to a 
level that is equal to or greater than the maximum organic vapor 
pressure limit for the tank design capacity category specified in 
paragraph (b)(1)(i) of this section, as applicable to the tank.
    (2) The tank shall be equipped with a fixed roof designed to meet 
the following specifications:
    (i) The fixed roof and its closure devices shall be designed to form 
a continuous barrier over the entire surface area of the hazardous waste 
in the tank. The fixed roof may be a separate cover installed on the 
tank (e.g., a removable cover mounted on an open-top tank) or may be an 
integral part of the tank structural design (e.g., a horizontal 
cylindrical tank equipped with a hatch).
    (ii) The fixed roof shall be installed in a manner such that there 
are no visible cracks, holes, gaps, or other open spaces between roof 
section joints or between the interface of the roof edge and the tank 
wall.
    (iii) Each opening in the fixed roof, and any manifold system 
associated with the fixed roof, shall be either:
    (A) Equipped with a closure device designed to operate such that 
when the closure device is secured in the closed position there are no 
visible cracks, holes, gaps, or other open spaces in the closure device 
or between the perimeter of the opening and the closure device; or
    (B) Connected by a closed-vent system that is vented to a control 
device. The control device shall remove or destroy organics in the vent 
stream, and shall be operating whenever hazardous waste is managed in 
the tank, except as provided for in paragraphs (c)(2)(iii)(B) (1) and 
(2) of this section.
    (1) During periods when it is necessary to provide access to the 
tank for performing the activities of paragraph (c)(2)(iii)(B)(2) of 
this section, venting of the vapor headspace underneath the fixed roof 
to the control device is not required, opening of closure devices is 
allowed, and removal of the fixed roof is allowed. Following completion 
of the activity, the owner or operator shall promptly secure the closure 
device in the closed position or reinstall the cover, as applicable, and 
resume operation of the control device.
    (2) During periods of routine inspection, maintenance, or other 
activities needed for normal operations, and for removal of accumulated 
sludge or other residues from the bottom of the tank.
    (iv) The fixed roof and its closure devices shall be made of 
suitable materials that will minimize exposure of the hazardous waste to 
the atmosphere, to the extent practical, and will maintain the integrity 
of the fixed roof and closure devices throughout their intended service 
life. Factors to be considered when selecting the materials for and 
designing the fixed roof and closure devices shall include: Organic 
vapor permeability, the effects of any contact with the hazardous waste 
or its vapors managed in the tank; the effects of

[[Page 420]]

outdoor exposure to wind, moisture, and sunlight; and the operating 
practices used for the tank on which the fixed roof is installed.
    (3) Whenever a hazardous waste is in the tank, the fixed roof shall 
be installed with each closure device secured in the closed position 
except as follows:
    (i) Opening of closure devices or removal of the fixed roof is 
allowed at the following times:
    (A) To provide access to the tank for performing routine inspection, 
maintenance, or other activities needed for normal operations. Examples 
of such activities include those times when a worker needs to open a 
port to sample the liquid in the tank, or when a worker needs to open a 
hatch to maintain or repair equipment. Following completion of the 
activity, the owner or operator shall promptly secure the closure device 
in the closed position or reinstall the cover, as applicable, to the 
tank.
    (B) To remove accumulated sludge or other residues from the bottom 
of tank.
    (ii) Opening of a spring-loaded pressure-vacuum relief valve, 
conservation vent, or similar type of pressure relief device which vents 
to the atmosphere is allowed during normal operations for the purpose of 
maintaining the tank internal pressure in accordance with the tank 
design specifications. The device shall be designed to operate with no 
detectable organic emissions when the device is secured in the closed 
position. The settings at which the device opens shall be established 
such that the device remains in the closed position whenever the tank 
internal pressure is within the internal pressure operating range 
determined by the owner or operator based on the tank manufacturer 
recommendations, applicable regulations, fire protection and prevention 
codes, standard engineering codes and practices, or other requirements 
for the safe handling of flammable, ignitable, explosive, reactive, or 
hazardous materials. Examples of normal operating conditions that may 
require these devices to open are during those times when the tank 
internal pressure exceeds the internal pressure operating range for the 
tank as a result of loading operations or diurnal ambient temperature 
fluctuations.
    (iii) Opening of a safety device, as defined in 40 CFR 265.1081, is 
allowed at any time conditions require doing so to avoid an unsafe 
condition.
    (4) The owner or operator shall inspect the air emission control 
equipment in accordance with the following requirements.
    (i) The fixed roof and its closure devices shall be visually 
inspected by the owner or operator to check for defects that could 
result in air pollutant emissions. Defects include, but are not limited 
to, visible cracks, holes, or gaps in the roof sections or between the 
roof and the tank wall; broken, cracked, or otherwise damaged seals or 
gaskets on closure devices; and broken or missing hatches, access 
covers, caps, or other closure devices.
    (ii) The owner or operator shall perform an initial inspection of 
the fixed roof and its closure devices on or before the date that the 
tank becomes subject to this section. Thereafter, the owner or operator 
shall perform the inspections at least once every year except under the 
special conditions provided for in paragraph (l) of this section.
    (iii) In the event that a defect is detected, the owner or operator 
shall repair the defect in accordance with the requirements of paragraph 
(k) of this section.
    (iv) The owner or operator shall maintain a record of the inspection 
in accordance with the requirements specified in Sec. 264.1089(b) of 
this subpart.
    (d) Owners and operators controlling air pollutant emissions from a 
tank using Tank Level 2 controls shall use one of the following tanks:
    (1) A fixed-roof tank equipped with an internal floating roof in 
accordance with the requirements specified in paragraph (e) of this 
section;
    (2) A tank equipped with an external floating roof in accordance 
with the requirements specified in paragraph (f) of this section;
    (3) A tank vented through a closed-vent system to a control device 
in accordance with the requirements specified in paragraph (g) of this 
section;

[[Page 421]]

    (4) A pressure tank designed and operated in accordance with the 
requirements specified in paragraph (h) of this section; or
    (5) A tank located inside an enclosure that is vented through a 
closed-vent system to an enclosed combustion control device in 
accordance with the requirements specified in paragraph (i) of this 
section.
    (e) The owner or operator who controls air pollutant emissions from 
a tank using a fixed roof with an internal floating roof shall meet the 
requirements specified in paragraphs (e)(1) through (e)(3) of this 
section.
    (1) The tank shall be equipped with a fixed roof and an internal 
floating roof in accordance with the following requirements:
    (i) The internal floating roof shall be designed to float on the 
liquid surface except when the floating roof must be supported by the 
leg supports.
    (ii) The internal floating roof shall be equipped with a continuous 
seal between the wall of the tank and the floating roof edge that meets 
either of the following requirements:
    (A) A single continuous seal that is either a liquid-mounted seal or 
a metallic shoe seal, as defined in 40 CFR 265.1081; or
    (B) Two continuous seals mounted one above the other. The lower seal 
may be a vapor-mounted seal.
    (iii) The internal floating roof shall meet the following 
specifications:
    (A) Each opening in a noncontact internal floating roof except for 
automatic bleeder vents (vacuum breaker vents) and the rim space vents 
is to provide a projection below the liquid surface.
    (B) Each opening in the internal floating roof shall be equipped 
with a gasketed cover or a gasketed lid except for leg sleeves, 
automatic bleeder vents, rim space vents, column wells, ladder wells, 
sample wells, and stub drains.
    (C) Each penetration of the internal floating roof for the purpose 
of sampling shall have a slit fabric cover that covers at least 90 
percent of the opening.
    (D) Each automatic bleeder vent and rim space vent shall be 
gasketed.
    (E) Each penetration of the internal floating roof that allows for 
passage of a ladder shall have a gasketed sliding cover.
    (F) Each penetration of the internal floating roof that allows for 
passage of a column supporting the fixed roof shall have a flexible 
fabric sleeve seal or a gasketed sliding cover.
    (2) The owner or operator shall operate the tank in accordance with 
the following requirements:
    (i) When the floating roof is resting on the leg supports, the 
process of filling, emptying, or refilling shall be continuous and shall 
be completed as soon as practical.
    (ii) Automatic bleeder vents are to be set closed at all times when 
the roof is floating, except when the roof is being floated off or is 
being landed on the leg supports.
    (iii) Prior to filling the tank, each cover, access hatch, gauge 
float well or lid on any opening in the internal floating roof shall be 
bolted or fastened closed (i.e., no visible gaps). Rim space vents are 
to be set to open only when the internal floating roof is not floating 
or when the pressure beneath the rim exceeds the manufacturer's 
recommended setting.
    (3) The owner or operator shall inspect the internal floating roof 
in accordance with the procedures specified as follows:
    (i) The floating roof and its closure devices shall be visually 
inspected by the owner or operator to check for defects that could 
result in air pollutant emissions. Defects include, but are not limited 
to: The internal floating roof is not floating on the surface of the 
liquid inside the tank; liquid has accumulated on top of the internal 
floating roof; any portion of the roof seals have detached from the roof 
rim; holes, tears, or other openings are visible in the seal fabric; the 
gaskets no longer close off the hazardous waste surface from the 
atmosphere; or the slotted membrane has more than 10 percent open area.
    (ii) The owner or operator shall inspect the internal floating roof 
components as follows except as provided in paragraph (e)(3)(iii) of 
this section:
    (A) Visually inspect the internal floating roof components through

[[Page 422]]

openings on the fixed-roof (e.g., manholes and roof hatches) at least 
once every 12 months after initial fill, and
    (B) Visually inspect the internal floating roof, primary seal, 
secondary seal (if one is in service), gaskets, slotted membranes, and 
sleeve seals (if any) each time the tank is emptied and degassed and at 
least every 10 years.
    (iii) As an alternative to performing the inspections specified in 
paragraph (e)(3)(ii) of this section for an internal floating roof 
equipped with two continuous seals mounted one above the other, the 
owner or operator may visually inspect the internal floating roof, 
primary and secondary seals, gaskets, slotted membranes, and sleeve 
seals (if any) each time the tank is emptied and degassed and at least 
every 5 years.
    (iv) Prior to each inspection required by paragraph (e)(3)(ii) or 
(e)(3)(iii) of this section, the owner or operator shall notify the 
Regional Administrator in advance of each inspection to provide the 
Regional Administrator with the opportunity to have an observer present 
during the inspection. The owner or operator shall notify the Regional 
Administrator of the date and location of the inspection as follows:
    (A) Prior to each visual inspection of an internal floating roof in 
a tank that has been emptied and degassed, written notification shall be 
prepared and sent by the owner or operator so that it is received by the 
Regional Administrator at least 30 calendar days before refilling the 
tank except when an inspection is not planned as provided for in 
paragraph (e)(3)(iv)(B) of this section.
    (B) When a visual inspection is not planned and the owner or 
operator could not have known about the inspection 30 calendar days 
before refilling the tank, the owner or operator shall notify the 
Regional Administrator as soon as possible, but no later than 7 calendar 
days before refilling of the tank. This notification may be made by 
telephone and immediately followed by a written explanation for why the 
inspection is unplanned. Alternatively, written notification, including 
the explanation for the unplanned inspection, may be sent so that it is 
received by the Regional Administrator at least 7 calendar days before 
refilling the tank.
    (v) In the event that a defect is detected, the owner or operator 
shall repair the defect in accordance with the requirements of paragraph 
(k) of this section.
    (vi) The owner or operator shall maintain a record of the inspection 
in accordance with the requirements specified in Sec. 264.1089(b) of 
this subpart.
    (4) Safety devices, as defined in 40 CFR 265.1081, may be installed 
and operated as necessary on any tank complying with the requirements of 
paragraph (e) of this section.
    (f) The owner or operator who controls air pollutant emissions from 
a tank using an external floating roof shall meet the requirements 
specified in paragraphs (f)(1) through (f)(3) of this section.
    (1) The owner or operator shall design the external floating roof in 
accordance with the following requirements:
    (i) The external floating roof shall be designed to float on the 
liquid surface except when the floating roof must be supported by the 
leg supports.
    (ii) The floating roof shall be equipped with two continuous seals, 
one above the other, between the wall of the tank and the roof edge. The 
lower seal is referred to as the primary seal, and the upper seal is 
referred to as the secondary seal.
    (A) The primary seal shall be a liquid-mounted seal or a metallic 
shoe seal, as defined in 40 CFR 265.1081. The total area of the gaps 
between the tank wall and the primary seal shall not exceed 212 square 
centimeters (cm2) per meter of tank diameter, and the width 
of any portion of these gaps shall not exceed 3.8 centimeters (cm). If a 
metallic shoe seal is used for the primary seal, the metallic shoe seal 
shall be designed so that one end extends into the liquid in the tank 
and the other end extends a vertical distance of at least 61 centimeters 
above the liquid surface.
    (B) The secondary seal shall be mounted above the primary seal and 
cover the annular space between the floating roof and the wall of the 
tank. The total area of the gaps between the tank wall and the secondary 
seal shall not exceed 21.2 square centimeters

[[Page 423]]

(cm2) per meter of tank diameter, and the width of any 
portion of these gaps shall not exceed 1.3 centimeters (cm).
    (iii) The external floating roof shall meet the following 
specifications:
    (A) Except for automatic bleeder vents (vacuum breaker vents) and 
rim space vents, each opening in a noncontact external floating roof 
shall provide a projection below the liquid surface.
    (B) Except for automatic bleeder vents, rim space vents, roof 
drains, and leg sleeves, each opening in the roof shall be equipped with 
a gasketed cover, seal, or lid.
    (C) Each access hatch and each gauge float well shall be equipped 
with a cover designed to be bolted or fastened when the cover is secured 
in the closed position.
    (D) Each automatic bleeder vent and each rim space vent shall be 
equipped with a gasket.
    (E) Each roof drain that empties into the liquid managed in the tank 
shall be equipped with a slotted membrane fabric cover that covers at 
least 90 percent of the area of the opening.
    (F) Each unslotted and slotted guide pole well shall be equipped 
with a gasketed sliding cover or a flexible fabric sleeve seal.
    (G) Each unslotted guide pole shall be equipped with a gasketed cap 
on the end of the pole.
    (H) Each slotted guide pole shall be equipped with a gasketed float 
or other device which closes off the liquid surface from the atmosphere.
    (I) Each gauge hatch and each sample well shall be equipped with a 
gasketed cover.
    (2) The owner or operator shall operate the tank in accordance with 
the following requirements:
    (i) When the floating roof is resting on the leg supports, the 
process of filling, emptying, or refilling shall be continuous and shall 
be completed as soon as practical.
    (ii) Except for automatic bleeder vents, rim space vents, roof 
drains, and leg sleeves, each opening in the roof shall be secured and 
maintained in a closed position at all times except when the closure 
device must be open for access.
    (iii) Covers on each access hatch and each gauge float well shall be 
bolted or fastened when secured in the closed position.
    (iv) Automatic bleeder vents shall be set closed at all times when 
the roof is floating, except when the roof is being floated off or is 
being landed on the leg supports.
    (v) Rim space vents shall be set to open only at those times that 
the roof is being floated off the roof leg supports or when the pressure 
beneath the rim seal exceeds the manufacturer's recommended setting.
    (vi) The cap on the end of each unslotted guide pole shall be 
secured in the closed position at all times except when measuring the 
level or collecting samples of the liquid in the tank.
    (vii) The cover on each gauge hatch or sample well shall be secured 
in the closed position at all times except when the hatch or well must 
be opened for access.
    (viii) Both the primary seal and the secondary seal shall completely 
cover the annular space between the external floating roof and the wall 
of the tank in a continuous fashion except during inspections.
    (3) The owner or operator shall inspect the external floating roof 
in accordance with the procedures specified as follows:
    (i) The owner or operator shall measure the external floating roof 
seal gaps in accordance with the following requirements:
    (A) The owner or operator shall perform measurements of gaps between 
the tank wall and the primary seal within 60 calendar days after initial 
operation of the tank following installation of the floating roof and, 
thereafter, at least once every 5 years.
    (B) The owner or operator shall perform measurements of gaps between 
the tank wall and the secondary seal within 60 calendar days after 
initial operation of the tank following installation of the floating 
roof and, thereafter, at least once every year.
    (C) If a tank ceases to hold hazardous waste for a period of 1 year 
or more, subsequent introduction of hazardous waste into the tank shall 
be considered an initial operation for the purposes of

[[Page 424]]

paragraphs (f)(3)(i)(A) and (f)(3)(i)(B) of this section.
    (D) The owner or operator shall determine the total surface area of 
gaps in the primary seal and in the secondary seal individually using 
the following procedure:
    (1) The seal gap measurements shall be performed at one or more 
floating roof levels when the roof is floating off the roof supports.
    (2) Seal gaps, if any, shall be measured around the entire perimeter 
of the floating roof in each place where a 0.32-centimeter (cm) diameter 
uniform probe passes freely (without forcing or binding against the 
seal) between the seal and the wall of the tank and measure the 
circumferential distance of each such location.
    (3) For a seal gap measured under paragraph (f)(3) of this section, 
the gap surface area shall be determined by using probes of various 
widths to measure accurately the actual distance from the tank wall to 
the seal and multiplying each such width by its respective 
circumferential distance.
    (4) The total gap area shall be calculated by adding the gap surface 
areas determined for each identified gap location for the primary seal 
and the secondary seal individually, and then dividing the sum for each 
seal type by the nominal diameter of the tank. These total gap areas for 
the primary seal and secondary seal are then compared to the respective 
standards for the seal type as specified in paragraph (f)(1)(ii) of this 
section.
    (E) In the event that the seal gap measurements do not conform to 
the specifications in paragraph (f)(1)(ii) of this section, the owner or 
operator shall repair the defect in accordance with the requirements of 
paragraph (k) of this section.
    (F) The owner or operator shall maintain a record of the inspection 
in accordance with the requirements specified in Sec. 264.1089(b) of 
this subpart.
    (ii) The owner or operator shall visually inspect the external 
floating roof in accordance with the following requirements:
    (A) The floating roof and its closure devices shall be visually 
inspected by the owner or operator to check for defects that could 
result in air pollutant emissions. Defects include, but are not limited 
to: Holes, tears, or other openings in the rim seal or seal fabric of 
the floating roof; a rim seal detached from the floating roof; all or a 
portion of the floating roof deck being submerged below the surface of 
the liquid in the tank; broken, cracked, or otherwise damaged seals or 
gaskets on closure devices; and broken or missing hatches, access 
covers, caps, or other closure devices.
    (B) The owner or operator shall perform an initial inspection of the 
external floating roof and its closure devices on or before the date 
that the tank becomes subject to this section. Thereafter, the owner or 
operator shall perform the inspections at least once every year except 
for the special conditions provided for in paragraph (l) of this 
section.
    (C) In the event that a defect is detected, the owner or operator 
shall repair the defect in accordance with the requirements of paragraph 
(k) of this section.
    (D) The owner or operator shall maintain a record of the inspection 
in accordance with the requirements specified in Sec. 264.1089(b) of 
this subpart.
    (iii) Prior to each inspection required by paragraph (f)(3)(i) or 
(f)(3)(ii) of this section, the owner or operator shall notify the 
Regional Administrator in advance of each inspection to provide the 
Regional Administrator with the opportunity to have an observer present 
during the inspection. The owner or operator shall notify the Regional 
Administrator of the date and location of the inspection as follows:
    (A) Prior to each inspection to measure external floating roof seal 
gaps as required under paragraph (f)(3)(i) of this section, written 
notification shall be prepared and sent by the owner or operator so that 
it is received by the Regional Administrator at least 30 calendar days 
before the date the measurements are scheduled to be performed.
    (B) Prior to each visual inspection of an external floating roof in 
a tank that has been emptied and degassed, written notification shall be 
prepared and sent by the owner or operator so that it is received by the 
Regional Administrator at least 30 calendar days before

[[Page 425]]

refilling the tank except when an inspection is not planned as provided 
for in paragraph (f)(3)(iii)(C) of this section.
    (C) When a visual inspection is not planned and the owner or 
operator could not have known about the inspection 30 calendar days 
before refilling the tank, the owner or operator shall notify the 
Regional Administrator as soon as possible, but no later than 7 calendar 
days before refilling of the tank. This notification may be made by 
telephone and immediately followed by a written explanation for why the 
inspection is unplanned. Alternatively, written notification, including 
the explanation for the unplanned inspection, may be sent so that it is 
received by the Regional Administrator at least 7 calendar days before 
refilling the tank.
    (4) Safety devices, as defined in 40 CFR 265.1081, may be installed 
and operated as necessary on any tank complying with the requirements of 
paragraph (f) of this section.
    (g) The owner or operator who controls air pollutant emissions from 
a tank by venting the tank to a control device shall meet the 
requirements specified in paragraphs (g)(1) through (g)(3) of this 
section.
    (1) The tank shall be covered by a fixed roof and vented directly 
through a closed-vent system to a control device in accordance with the 
following requirements:
    (i) The fixed roof and its closure devices shall be designed to form 
a continuous barrier over the entire surface area of the liquid in the 
tank.
    (ii) Each opening in the fixed roof not vented to the control device 
shall be equipped with a closure device. If the pressure in the vapor 
headspace underneath the fixed roof is less than atmospheric pressure 
when the control device is operating, the closure devices shall be 
designed to operate such that when the closure device is secured in the 
closed position there are no visible cracks, holes, gaps, or other open 
spaces in the closure device or between the perimeter of the cover 
opening and the closure device. If the pressure in the vapor headspace 
underneath the fixed roof is equal to or greater than atmospheric 
pressure when the control device is operating, the closure device shall 
be designed to operate with no detectable organic emissions.
    (iii) The fixed roof and its closure devices shall be made of 
suitable materials that will minimize exposure of the hazardous waste to 
the atmosphere, to the extent practical, and will maintain the integrity 
of the fixed roof and closure devices throughout their intended service 
life. Factors to be considered when selecting the materials for and 
designing the fixed roof and closure devices shall include: Organic 
vapor permeability, the effects of any contact with the liquid and its 
vapor managed in the tank; the effects of outdoor exposure to wind, 
moisture, and sunlight; and the operating practices used for the tank on 
which the fixed roof is installed.
    (iv) The closed-vent system and control device shall be designed and 
operated in accordance with the requirements of Sec. 264.1087 of this 
subpart.
    (2) Whenever a hazardous waste is in the tank, the fixed roof shall 
be installed with each closure device secured in the closed position and 
the vapor headspace underneath the fixed roof vented to the control 
device except as follows:
    (i) Venting to the control device is not required, and opening of 
closure devices or removal of the fixed roof is allowed at the following 
times:
    (A) To provide access to the tank for performing routine inspection, 
maintenance, or other activities needed for normal operations. Examples 
of such activities include those times when a worker needs to open a 
port to sample liquid in the tank, or when a worker needs to open a 
hatch to maintain or repair equipment. Following completion of the 
activity, the owner or operator shall promptly secure the closure device 
in the closed position or reinstall the cover, as applicable, to the 
tank.
    (B) To remove accumulated sludge or other residues from the bottom 
of a tank.
    (ii) Opening of a safety device, as defined in 40 CFR 265.1081, is 
allowed at any time conditions require doing so to avoid an unsafe 
condition.
    (3) The owner or operator shall inspect and monitor the air emission

[[Page 426]]

control equipment in accordance with the following procedures:
    (i) The fixed roof and its closure devices shall be visually 
inspected by the owner or operator to check for defects that could 
result in air pollutant emissions. Defects include, but are not limited 
to, visible cracks, holes, or gaps in the roof sections or between the 
roof and the tank wall; broken, cracked, or otherwise damaged seals or 
gaskets on closure devices; and broken or missing hatches, access 
covers, caps, or other closure devices.
    (ii) The closed-vent system and control device shall be inspected 
and monitored by the owner or operator in accordance with the procedures 
specified in Sec. 264.1087 of this subpart.
    (iii) The owner or operator shall perform an initial inspection of 
the air emission control equipment on or before the date that the tank 
becomes subject to this section. Thereafter, the owner or operator shall 
perform the inspections at least once every year except for the special 
conditions provided for in paragraph (l) of this section.
    (iv) In the event that a defect is detected, the owner or operator 
shall repair the defect in accordance with the requirements of paragraph 
(k) of this section.
    (v) The owner or operator shall maintain a record of the inspection 
in accordance with the requirements specified in Sec. 264.1089(b) of 
this subpart.
    (h) The owner or operator who controls air pollutant emissions by 
using a pressure tank shall meet the following requirements.
    (1) The tank shall be designed not to vent to the atmosphere as a 
result of compression of the vapor headspace in the tank during filling 
of the tank to its design capacity.
    (2) All tank openings shall be equipped with closure devices 
designed to operate with no detectable organic emissions as determined 
using the procedure specified in Sec. 264.1083(d) of this subpart.
    (3) Whenever a hazardous waste is in the tank, the tank shall be 
operated as a closed system that does not vent to the atmosphere except 
under either or the following conditions as specified in paragraph 
(h)(3)(i) or (h)(3)(ii) of this section.
    (i) At those times when opening of a safety device, as defined in 
Sec. 265.1081 of this subpart, is required to avoid an unsafe 
condition.
    (ii) At those times when purging of inerts from the tank is required 
and the purge stream is routed to a closed-vent system and control 
device designed and operated in accordance with the requirements of 
Sec. 264.1087 of this subpart.
    (i) The owner or operator who controls air pollutant emissions by 
using an enclosure vented through a closed-vent system to an enclosed 
combustion control device shall meet the requirements specified in 
paragraphs (i)(1) through (i)(4) of this section.
    (1) The tank shall be located inside an enclosure. The enclosure 
shall be designed and operated in accordance with the criteria for a 
permanent total enclosure as specified in ``Procedure T--Criteria for 
and Verification of a Permanent or Temporary Total Enclosure'' under 40 
CFR 52.741, appendix B. The enclosure may have permanent or temporary 
openings to allow worker access; passage of material into or out of the 
enclosure by conveyor, vehicles, or other mechanical means; entry of 
permanent mechanical or electrical equipment; or direct airflow into the 
enclosure. The owner or operator shall perform the verification 
procedure for the enclosure as specified in Section 5.0 to ``Procedure 
T--Criteria for and Verification of a Permanent or Temporary Total 
Enclosure'' initially when the enclosure is first installed and, 
thereafter, annually.
    (2) The enclosure shall be vented through a closed-vent system to an 
enclosed combustion control device that is designed and operated in 
accordance with the standards for either a vapor incinerator, boiler, or 
process heater specified in Sec. 264.1087 of this subpart.
    (3) Safety devices, as defined in 40 CFR 265.1081, may be installed 
and operated as necessary on any enclosure, closed-vent system, or 
control device used to comply with the requirements of paragraphs (i)(1) 
and (i)(2) of this section.
    (4) The owner or operator shall inspect and monitor the closed-vent 
system and control device as specified in Sec. 264.1087 of this 
subpart.

[[Page 427]]

    (j) The owner or operator shall transfer hazardous waste to a tank 
subject to this section in accordance with the following requirements:
    (1) Transfer of hazardous waste, except as provided in paragraph 
(j)(2) of this section, to the tank from another tank subject to this 
section or from a surface impoundment subject to Sec. 264.1085 of this 
subpart shall be conducted using continuous hard-piping or another 
closed system that does not allow exposure of the hazardous waste to the 
atmosphere. For the purpose of complying with this provision, an 
individual drain system is considered to be a closed system when it 
meets the requirements of 40 CFR part 63, subpart RR--National Emission 
Standards for Individual Drain Systems.
    (2) The requirements of paragraph (j)(1) of this section do not 
apply when transferring a hazardous waste to the tank under any of the 
following conditions:
    (i) The hazardous waste meets the average VO concentration 
conditions specified in Sec. 264.1082(c)(1) of this subpart at the 
point of waste origination.
    (ii) The hazardous waste has been treated by an organic destruction 
or removal process to meet the requirements in Sec. 264.1082(c)(2) of 
this subpart.
    (iii) The hazardous waste meets the requirements of Sec. 
264.1082(c)(4) of this subpart.
    (k) The owner or operator shall repair each defect detected during 
an inspection performed in accordance with the requirements of paragraph 
(c)(4), (e)(3), (f)(3), or (g)(3) of this section as follows:
    (1) The owner or operator shall make first efforts at repair of the 
defect no later than 5 calendar days after detection, and repair shall 
be completed as soon as possible but no later than 45 calendar days 
after detection except as provided in paragraph (k)(2) of this section.
    (2) Repair of a defect may be delayed beyond 45 calendar days if the 
owner or operator determines that repair of the defect requires emptying 
or temporary removal from service of the tank and no alternative tank 
capacity is available at the site to accept the hazardous waste normally 
managed in the tank. In this case, the owner or operator shall repair 
the defect the next time the process or unit that is generating the 
hazardous waste managed in the tank stops operation. Repair of the 
defect shall be completed before the process or unit resumes operation.
    (l) Following the initial inspection and monitoring of the cover as 
required by the applicable provisions of this subpart, subsequent 
inspection and monitoring may be performed at intervals longer than 1 
year under the following special conditions:
    (1) In the case when inspecting or monitoring the cover would expose 
a worker to dangerous, hazardous, or other unsafe conditions, then the 
owner or operator may designate a cover as an ``unsafe to inspect and 
monitor cover'' and comply with all of the following requirements:
    (i) Prepare a written explanation for the cover stating the reasons 
why the cover is unsafe to visually inspect or to monitor, if required.
    (ii) Develop and implement a written plan and schedule to inspect 
and monitor the cover, using the procedures specified in the applicable 
section of this subpart, as frequently as practicable during those times 
when a worker can safely access the cover.
    (2) In the case when a tank is buried partially or entirely 
underground, an owner or operator is required to inspect and monitor, as 
required by the applicable provisions of this section, only those 
portions of the tank cover and those connections to the tank (e.g., fill 
ports, access hatches, gauge wells, etc.) that are located on or above 
the ground surface.

[61 FR 59955, Nov. 25, 1996, as amended at 62 FR 64659, Dec. 8, 1997; 64 
FR 3389, Jan. 21, 1999]