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(Adopted January 7, 2005)(Amended September 8, 2006)

RULE 1157. PM10 EMISSION REDUCTIONS FROM AGGREGATE AND 

RELATED OPERATIONS

(a) Purpose

The purpose of this rule is to reduce PM10 emissions from aggregate and related 

operations.

(b) Applicability

This rule applies to all permanent and temporary aggregate and related operations, 

unless otherwise exempt under subdivision (h).

(c) Definitions

(1) AGGREGATE OPERATIONS are defined as operations that produce 

sand, gravel, crushed stone, and/or quarried rocks.

(2) AGGREGATE OR RELATED MATERIAL means material that is 

produced and/or used by the aggregate and related operations.

(3) AGGREGATE TRUCKS mean trucks with open tops, used to transport 

the products of the aggregate and related operations to other processors, 

retailers, or end users.

(4) BLASTING OPERATIONS are defined as operations that break or 

displace rock by means of explosives.

(5) BUNKER is defined as a three-sided enclosure of which one side may be a 

windscreen with a maximum porosity of 20%.

(6) CARRY-BACK is defined as materials that fall off the underside of the 

conveyor belt and accumulate on the ground.

(7) CHEMICAL STABILIZERS are any non-toxic chemical dust suppressant. 

The chemical stabilizers shall meet any specifications, criteria, or tests 

required by any federal, state, or local water agency.

(8) CONVEYOR means an above-ground, outdoor conveyor system to move

materials from any location, process, or equipment to another in a 

continuous fashion.

(9) DISTURBED SURFACE AREA means a portion of a surface which has 

been physically moved, uncovered, destabilized, or otherwise modified 

from its undisturbed natural soil condition, thereby increasing the potential 
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for emission of fugitive dust. This definition excludes those areas which 

have:

(A) been restored to a natural state, such that the vegetative ground 

cover and soil characteristics are similar to adjacent or nearby 

natural conditions;

(B) been paved or otherwise completely covered by a permanent 

structure; or

(C) sustained a vegetative ground cover of at least 70 percent of the 

native cover for a particular area for at least 30 days.

(10) DUST SUPPRESSANTS are water, hygroscopic materials, or chemical 

stabilizers used as a treatment material to reduce fugitive dust emissions.

(11) ENCLOSED SCREENING EQUIPMENT means screening equipment 

where the top portion of the equipment is enclosed, except for the area 

where materials enter the screening equipment.

(12) END OF WORK DAY means the end of a working period that may 

include one or more work shifts, but no later than 8 p.m.

(13) EQUIPMENT BREAKDOWN means an unforeseeable impairment of an 

air pollution control equipment or related operating equipment which 

causes a violation of any emission limitation or restriction prescribed by 

this rule or by State law and which: is not the result of neglect or disregard 

of any air pollution control law, rule, or regulation; is not a recurrent 

breakdown of the same equipment; and, does not constitute a nuisance as 

defined in the State of California Health and Safety Code, Section 41700, 

with the burden of proving the criteria of this section placed upon the 

person seeking to come under the provisions of this rule.

(14) EXISTING FACILITY/OPERATION means a facility or an operation that 

has begun to operate, or has an application for Permit to Construct that has 

been deemed complete by the Executive Officer on or before December 3, 

2004.

(15) FRONT-END LOADER means a wheeled or tractor loader, with a bucket 

or fork hinged to lifting arms that loads or digs entirely at the front end.

(16) FUGITIVE DUST means any solid particulate matter that becomes 

airborne, other than that emitted from an exhaust stack, directly or 

indirectly as a result of the activities of any person.
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(17) GEOTEXTILE means permeable textile, including but not limited to, 

mesh, net, or even grid that is used in contact with soil or rocks with the 

purpose of adding stability to the gravel pad.

(18) HAUL ROAD means an unpaved road that is used by haul trucks to carry 

materials from the quarry to different locations within the facility.

(19) HAUL TRUCK means a diesel heavy-duty truck having a minimum 

capacity of 50 tons and is used to transport aggregates within the facility.

(20) HIGH WINDS means instantaneous wind speeds exceed 25 miles per 

hour.

(21) INFREQUENT MINING OPERATIONS mean operations that have state 

mine IDs, approved reclamation plans and bonding as required by State 

Mining and Reclamation Act of 1975, and only operate on an average of 

52 days per year over the past three years from December 3, 2004.

(22) INTERNAL ROADS mean private paved and unpaved roads within the 

facility’s property boundary.

(23) LOADING means an activity to move materials from any location to a 

truck.

(24) MATERIAL SPILLAGE means material inadvertently lost or scattered by 

spilling.

(25) MIXER TRUCK means truck that mixes cement and other ingredients in a 

drum to produce concrete.

(26) NEW FACILITY/OPERATION means a facility or an operation that has 

not begun to operate, or does not have an application for Permit to 

Construct that has been deemed complete by the Executive Officer as of 

December 3, 2004.

(27) NON-POROUS WALLS are walls that have zero percent porosity. Nonporous walls include but are not limited to concrete and steel walls.

(28) OPEN STORAGE PILE is any accumulation of aggregate or related 

material which is not fully enclosed, covered or chemically stabilized, and 

which attains a height of three feet or more and a total surface area of 150 

or more square feet.

(29) OTHER DUST CONTROL METHODS including but not limited to 

baghouses, filter bags, enclosures, and partial enclosures.

(30) PAVED ROAD means a public or private improved street, highway, alley, 

public way, or easement that is covered by typical roadway materials, but 
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excluding access roadways that connect a facility with a public paved 

roadway and are not open to through traffic. Public paved roads are those 

open to public access and that are owned by any federal, state, county, 

municipal or any other governmental or quasi-governmental agencies. 

Private paved roads are any paved roads not defined as public.

(31) PERMANENT FACILITY/OPERATION means a facility or an operation 

that is performed at one physical location for more than two years.

(32) PM10 means particulate matter with an aerodynamic diameter smaller than 

or equal to 10 microns as measured by the applicable State and Federal 

reference test methods.

(33) PRODUCTION WORK SHIFT is an eight hour operating period based on 

the 24 hour operating schedule.

(34) RELATED OPERATIONS are defined as operations that use sand, gravel, 

cement, crushed stone, and/or quarried rocks in their products, or crush 

miscellaneous base, and inert landfills that handle construction/demolition 

debris.

(35) RETURNED PRODUCTS mean left over concrete or asphalt products

that were not used at the job sites and were brought back to the facility.

(36) RUMBLE GRATE is a system where the vehicle is vibrated while 

traveling over grates with the purpose of removing dust and other debris.

(37) SCALPING SCREEN means a screen where debris and oversized 

materials are rejected.

(38) SENSITIVE RECEPTOR is a school (kindergarten through grade 12), 

licensed daycare center, hospital, or convalescent home.

(39) SILO means an elevated storage container, with or without a top, that 

releases material through the bottom.

(40) STABILIZED SURFACE means any previously disturbed surface area or 

open storage pile which, through the application of dust suppressants, 

shows visual or other evidence of surface crusting and is resistant to winddriven fugitive dust and is demonstrated to be stabilized. Stabilization can 

be demonstrated by one or more of the applicable test methods contained 

in the Rule 403 Implementation Handbook.

(41) STAGING AREA is a place where aggregate and mixer trucks temporarily

queue for their loading or unloading turn.
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(42) TEMPORARY FACILITY/OPERATION means a facility that operates or 

an operation that is performed at one physical location for two years or 

less. Temporary facility/operation includes portable facility/operation.

(43) TRACK-OUT means any material that adheres to and agglomerates on the 

exterior surface of motor vehicles, haul trucks, and equipment (including 

tires) that has been released onto a paved road and can be removed by a 

vacuum sweeper or a broom sweeper under normal operating conditions.

(44) TRANSFER means an activity to move materials from any location to any 

location within a facility.

(45) TRANSFER POINT is a point in a conveying system where the materials 

are dropped onto a stockpile, equipment, or another conveyor, or where a 

conveyor belt enters or exits the processing equipment.

(46) TRUCK TRIMMING AREA means an area where trucks that are exiting a 

facility/operation are inspected to determine whether the amount and type 

of loaded material is correct. Any excess material is removed in this area 

of the facility/operation.

(47) TRUCK WASHER means a system that is used to wash the entire surface 

and the tires of a truck.

(48) TUNNEL FEED is underground belt conveyor system to move the 

materials from any location to any location within a facility in a 

continuous fashion.

(49) TYPICAL ROADWAY MATERIALS means concrete, asphaltic concrete, 

recycled asphalt, asphalt, or any other material of equivalent performance 

as determined by the Executive Officer and the U.S. EPA.

(50) UNLOADING means an activity to release the materials from a truck or a 

front-end loader to any location located inside the facility.

(51) UNPAVED ROADS mean any roads, equipment paths, or travel ways that 

are not covered by typical roadway materials. Public unpaved roads are 

any unpaved roadway owned by Federal, State, county, municipal or other 

governmental or quasi-governmental agencies. Private unpaved roads are 

all other unpaved roadways not defined as public. Internal unpaved roads 

are private unpaved roads within the facility’s property boundary.

(52) WATER IRRIGATION SYSTEM means devices that are mounted above 

an open storage pile to deliver water to a pile.
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(53) WHEEL WASHER means a system that is capable of washing the entire 

circumference of each wheel of the vehicle.

(54) VALIDATED NOTICE OF VIOLATION means a notice of violation 

issued by a District enforcement officer that has been finally resolved by 

means of either a settlement with the alleged violator resulting in the 

payment of a civil penalty in any amount or a court judgment imposing 

civil or criminal liability on the alleged violator based on the conduct 

alleged in the notice of violation.

(d) Requirements

Unless otherwise stated, effective July 1, 2005, aggregate and related operations 

shall comply with the following requirements:

(1) General Performance Standards

(A) The operator of a facility/operation shall not cause or allow:

(i) a discharge into the atmosphere of, fugitive dust emissions 

exceeding 20 percent opacity from any activity, equipment, 

storage pile, or disturbed surface area, based on an average 

of 12 consecutive readings, using the SCAQMD Opacity 

Test Method No. 9B; or

(ii) discharges into the atmosphere of, fugitive dust emissions 

exceeding 50 percent opacity from any activity, equipment, 

storage pile, or disturbed surface area, based on five 

individual, consecutive readings, using the SCAQMD 

Opacity Test Method No. 9B, effective December 3, 2005; 

or

(iii) any visible fugitive dust plume from exceeding 100 feet in 

any direction from any activity, equipment, storage pile, or 

disturbed surface area.

(B) The operator of a facility/operation shall promptly remove any pile 

of material spillage on any internal paved roads. Alternatively, the 

operator shall maintain in a stabilized condition the pile of material 

spillage with dust suppressants and remove it by the end of each 

day.

(C) The operator of a facility/operation shall maintain in a stabilized 

condition all other piles of material spillage and carry-back with 

dust suppressants until removal.
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(D) The operator of a facility/operation shall use sufficient dust 

suppressants or other dust control methods as necessary to meet the 

performance standards in subparagraph (d)(1)(A).

(E) Where applicable, the operator shall install a gravel pad that:

(i) Contains one-inch or larger washed gravel maintained to a 

depth of six inches;

(ii) Has a geotextile lining underneath the washed gravel; and

(iii) Is flushed with water or is completely replaced, as 

necessary to comply with the track out threshold set forth in 

Rule 403.

(2) Loading, Unloading, and Transferring

The operator of an existing permanent or temporary facility/operation shall 

use dust suppressants or other dust control methods at each emission 

source during loading, unloading, or transferring activities of materials as 

necessary to meet the performance standards in subparagraph (d)(1)(A).

(3) Conveyor

The operator of a facility/operation using a conveyor shall apply dust 

suppressants or other dust control methods at the conveyor including all 

transfer points where materials are released as necessary to meet the 

performance standards in subparagraph (d)(1)(A).

(4) Crushing Equipment

The operator of a facility/operation conducting crushing activities of 

materials shall use baghouses to control PM10 emissions. Alternatively, 

the operator may apply dust suppressants or other dust control methods at 

the crusher including all discharge points as necessary to meet the 

performance standards in subparagraph (d)(1)(A).

(5) Screening Equipment

The operator of a facility/operation conducting outdoor screening activities 

of materials shall use enclosed screening equipment that is equipped with 

a baghouse. Alternatively, the operator may apply dust suppressants or 

other dust control methods at the screening equipment including all 

discharge points during such activities as necessary to meet the 

performance standards in subparagraph (d)(1)(A). 

(6) Storage Piles
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(A) The operator of a facility/operation shall maintain in a stabilized 

condition the entire surface area of the open storage piles of 

materials, except for areas of the piles that are actively disturbed 

during the loading and/or unloading activities. Alternatively, the 

operator may:

(i) store materials in a silo or a bunker;

(ii) maintain at least two feet of freeboard from the highest 

portion of the piles; and

(iii) for the bunker, stabilize the sides of the pile that are not 

shielded by non-porous walls.

(B) At the end of each work day in which loading or unloading 

activities of materials were performed, the operator of a 

facility/operation shall re-apply dust suppressants to re-stabilize 

disturbed areas of the piles.

(C) The operator of a facility/operation shall not allow any open 

storage piles of materials to be greater than eight feet height if such 

piles are located within 300 feet of off-site occupied buildings or 

houses. Alternatively, the operator of a facility/operation shall 

operate a water irrigation system to maintain in a stabilized 

condition the entire surface of the piles. 

(7) Internal Roads

(A) Unpaved Haul Roads

(i) The operator of a facility/operation shall apply chemical 

stabilizers on the internal unpaved haul roads so that the 

surface is maintained in a stabilized condition.

(ii) The operator of a facility/operation shall post signs at the 

two ends of the internal unpaved haul roads, stating that 

haul trucks shall use these roads unless traveling to the 

maintenance areas.

(B) Unpaved Non-Haul Roads and Parking and Staging Areas

The operator of a facility/operation shall apply chemical stabilizers 

on such unpaved roads and parking and staging areas so that the 

surface is maintained in a stabilized condition, or apply a gravel 

pad that meets the criteria set forth in subparagraph (d)(1)(E) on 
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the entire unpaved non-haul road and/or the parking and staging 

areas.

(C) Paved Roads

(i) The operator of a facility/operation with a minimum of 60 

aggregate and/or mixer trucks exiting the facility on any 

day shall sweep the internal paved roads with a street 

sweeper by the end of each production work shift.

(ii) The operator of a facility/operation with less than 60 

aggregate and/or mixer trucks exiting the facility on any 

day shall sweep the internal paved roads with a street 

sweeper by the end of every other work day. On the days 

that the roads are not swept, the operator shall apply water 

as necessary to comply with subparagraph (d)(1)(A) on at 

least 100 feet of paved roads, or the entire length of paved 

roads leading to an exit to public paved roads, if such roads 

are less than 100 feet long. 

(iii) Sweepers that are purchased after December 3, 2004 shall 

meet the criteria of PM10-efficient Rule 1186-certified 

sweepers. 

(iv) The operator of a new facility/operation shall use Rule 

1186-certified-sweepers to sweep the internal paved roads. 

(8) Track-Out

(A) The operator of a facility/operation and the drivers must take all 

reasonable steps to ensure that all loads on aggregate trucks are 

leveled and maintained with at least 6 inches of freeboard, and that 

the load is stabilized by applying dust suppressants in sufficient 

quantities so that the performance standards in subparagraph 

(d)(1)(A) are met, unless the driver tarps or suitably covers the load 

prior to entering paved public roads or prior to the use of a rumble 

grate and/or wheel washer.

(B) The operator of a facility/operation must post signs at the exits of 

the facility to require all loads to comply with the requirements in 

subparagraph (d)(8)(A).

(C) Effective December 3, 2005, the operator of a facility/operation 

not covered under subparagraph (d)(8)(D) shall install and utilize a 
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rumble grate, a wheel washer, or a truck washer in accordance with 

the following:

(i) The rumble grate, the wheel washer, or the truck washer 

shall be located no less than 30 feet prior to each exit that is 

used by aggregate and/or mixer trucks and leading to a 

paved public road;

(ii) The operator must ensure that all aggregate and mixer 

trucks leaving the facility go through the rumble grate, the 

wheel washer, or the truck washer;

(iii) The operator shall post a sign by the rumble grate, the 

wheel washer, or the truck washer to designate the speed 

limit to 5 miles per hour for using such control equipment; 

and

(iv) If the internal road from the rumble grate, the wheel

washer, or the truck washer to any paved public road is not 

paved, the operator shall apply a gravel pad that meets the 

criteria set forth in subparagraph (d)(1)(E) to such roads.

(v) An operator is not subject to clause (d)(8)(C)(i) if he can 

demonstrate to the Executive Officer, by July 1, 2005, that 

there is not adequate space for 30 feet of roadway and that a 

rumble grate, a wheel washer, or a truck washer at a shorter 

distance will be adequate to prevent track out of dust to the 

public road. The operator of a new, temporary 

facility/operation shall provide such demonstration to the 

Executive Officer prior to the beginning of its operation. 

(D) Effective December 3, 2005, the operator of a new permanent 

facility/operation with land size in excess of 25 acres or with a 

designed daily throughput of 750 tons, and the operator of an 

existing permanent facility/operation with a minimum of 60 

aggregate and/or mixer trucks exiting the facility on any day shall 

install and utilize a rumble grate and a wheel washer in accordance 

to the following:

(i) The rumble grate and the wheel washer shall be located no 

less than 30 feet prior to each exit that is used by aggregate 

and/or mixer trucks and leading to a paved public road. 
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The rumble grate shall be located within 10 feet from the 

wheel washer.

(ii) The operator must ensure that all aggregate and mixer 

trucks leaving the facility go through the rumble grate first 

and then, the wheel washer.

(iii) The operator shall post a sign by the rumble grate to 

designate the speed limit to 5 miles per hour for traveling 

over the rumble grate and wheel washer.

(iv) The operator shall pave the internal roads from the rumble 

grate and the wheel washer to the facility exits leading to 

paved public roads.

(v) The operator must ensure that all aggregate and mixer 

trucks stay on the internal paved roads between the wheel 

washer and the facility exits leading to paved public roads.

(vi) An operator is not subject to clause (d)(8)(D)(i) if he can 

demonstrate to the Executive Officer, by July 1, 2005, that 

there is not adequate space for 30 feet of roadway and that a 

rumble grate and a wheel washer at a shorter distance will 

be adequate to prevent track out of dust to the public road. 

The operator of a new, permanent facility/operation shall 

provide such demonstration to the Executive Officer prior 

to the beginning of its operation.

(E) The operator of a facility/operation shall provide the “Fugitive 

Dust Advisory” information prepared by the District to the 

aggregate and/or mixer truck company and/or broker at least once 

each calendar year.

(9) The operator of a new permanent facility/operation shall comply with all 

requirements set forth in this rule and apply Best Available Control 

Technology required by the Executive Officer.

(10) New and/or modified equipment shall comply with 40 CFR Part 60, 

Subpart I and/or 40 CFR Part 60, Subpart OOO as appropriate.

(e) Recordkeeping:

The operator of a facility/operation shall keep the following records on-site for 3 

years, or 5 years for Title V facility, and make such records available to the 

Executive Officer upon request:
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(1) Records of watering and sweeping schedule for internal paved roads;

(2) Records of aggregate and/or mixer trucks exiting the facility;

(3) Records of “Fugitive Dust Advisory” information distribution;

(4) Records of new equipment initial start-up and/or existing equipment startup after a repair to fix an equipment breakdown if seeking exemption 

pursuant to subparagraphs (h)(1)(B) and/or (h)(1)(C);

(5) Records of scheduled maintenance activities if seeking exemption 

pursuant to subparagraph (h)(1)(A);

(6) Records of aggregate materials that meet the descriptions in subparagraphs 

(h)(2)(A) and (h)(2)(B); and

(7) Records of operating days if seeking exemption pursuant to subparagraph 

(h)(10)(D).

(f) Test Methods

The following test methods shall be used to determine compliance with this rule:

(1) SCAQMD Opacity Test Method No. 9B

(2) The Stabilized Surface Test Method included in the SCAQMD Rule 403 

Implementation Handbook.

(g) Additional Requirements Triggered by Recurrent Violation:

(1) The operator of an existing facility located within 500 meters of off-site 

occupied buildings or houses or a sensitive receptor, who accrues three or 

more validated notices of violation for causing or allowing fugitive dust 

emissions exceeding the opacity limits in clauses (d)(1)(A)(i) as measured 

by the test methods in (f), or a visible fugitive dust plume exceeding 100 

feet in any direction, issued on separate days for violations from the same 

emission source at the facility in any continuous twelve month period 

(“recurrent violations”) starting from December 3, 2005 shall, within 30 

days of the third notice of violation being validated, submit an emission 

reduction plan to the Executive Officer that meets the following 

requirements:

(A) The plan must propose additional emission control measures 

sufficient to remedy the causes of the recurrent violations and 

prevent future violations; and

(B) It must provide for implementation of the specified additional 

control measures at the earliest practicable date.
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(2) The Executive Officer shall approve the emission reduction plan within 30 

days of receipt of a complete plan if it is determined that implementation 

will likely remedy the causes of the recurrent violations. The Executive 

Officer may impose additional conditions in the plan if it is determined 

necessary to remedy the causes of the recurrent violations, however, the 

Executive Officer may not require, as a condition to approving an 

emission reduction plan under this paragraph, an operator to implement 

control measures that are economically or technologically infeasible, that 

do not directly address the cause of the recurrent violations, or that require 

the operator to take responsibility for the conduct of a third party over 

whom the operator has no legal control. A disapproval or conditional 

approval of a plan by the Executive Officer may be appealed to the 

Hearing Board.

(3) The Executive Officer shall disapprove any plan that does not demonstrate 

a substantial likelihood of preventing violations in the future. If a plan is 

disapproved, the responsible party shall submit a revised plan which cures 

the defects within 30 days of receipt of notice of disapproval.

(h) Exemptions

(1) The following activities will be exempt from requirements set forth in 

subparagraph (d)(1)(A):

(A) The first 8 hours of the new equipment initial start-up and the first 

2 hours of the equipment start-up after a repair to fix an equipment 

breakdown or after a maintenance activity scheduled at least 48 

hours in advance by the operator of a facility.

(B) Blasting operations.

(2) During high winds, the operator of a facility/operation will be exempt 

from the requirements in subparagraph (d)(1)(A) if:

(A) All activities, including aggregate excavation, production, loading 

and unloading activities, and material transport, are ceased, except 

for dust controls as required by District rules; or

(B) All excavation and earthmoving operations, except for underwater 

dredging and the transporting of dredged materials to the surge 

pile, and aggregate production (but not loading or transport) are 

ceased, provided:

(i) dust controls as required by District rules are applied; and
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(ii) unpaved roads have had chemical stabilizers applied prior 

to the wind event, or where unpaved roads have not had 

chemical stabilizers applied, water is applied twice per hour 

during active operations; and

(iii) within fifteen (15) minutes of each loading activity, water is 

applied to un-stabilized areas of open storage piles that will 

be actively disturbed during loading; or

(C) The only activities being conducted at ready-mixed concrete or hot 

mix asphalt facilities are those activities that produce materials for 

use in construction projects which are being paved or poured 

during high winds, provided that dust controls as required by 

District rules are applied.

(3) Scalping screens will be exempt from the enclosure required in 

paragraph (d)(5).

(4) The operator of a facility/operation is exempt from the use of chemical 

stabilizers for internal unpaved roads if the use of applicable chemical dust 

suppressants on those specific unpaved roads violates the rules and/or 

regulations of the local Water Quality Control Board or other government 

agency. Alternatively, the operator of a facility/operation may use water, 

proving that:

(A) Water is used in sufficient quantity and frequency on those specific 

internal unpaved roads so that the surface is maintained in a 

stabilized condition; and

(B) The operator notifies the Executive Officer in writing 30 days prior 

to the use of water and demonstrates that the use of chemical was 

not allowed on those specific unpaved roads.

(5) Empty haul trucks traveling to and from maintenance areas are exempt 

from the requirement to use internal unpaved haul roads if they travel on 

internal unpaved non-haul roads that comply with the requirement in 

subparagraph (d)(7)(B).

(6) The unpaved non-haul roads will be exempt from the requirement in 

subparagraph (d)(7)(B) if such roads are used less than twice a day, and 

signs are posted on such roads to restrict speed limit to 15 miles per hour 

and to restrict traffic to such vehicles only.
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(7) Carry-back that is generated by the tunnel feed will be exempt from the 

requirement set forth in subparagraph (d)(1)(C).

(8) Truck trimming areas are exempt from the requirement in subparagraph 

(d)(1)(C).

(9) Facilities where aggregate trucks are not used to carry aggregate or related 

materials to and off the facility property are exempt from the requirements 

in paragraph (d)(8).

(10) The following are not required to install and operate a wheel washer:

(A) Facilities that have their internal roads all paved and with the 

exception of returned products, their aggregate or related materials

metered directly to a ready-mix or hot mix asphalt truck. The 

facilities may accept returned products and are still qualified for 

the exemption from a wheel washer. The facilities are instead 

required to have a rumble grate or a truck washer and comply with 

subparagraph (d)(8)(C).

(B) Facilities with less than 5 acres in land size and handle recycled 

asphalt and recycled concrete exclusively, provided the facility 

installs a rumble grate, comply with clauses (d)(8)(C)(i) through 

(d)(8)(C)(iii), and applies a gravel pad that meets the criteria set 

forth in subparagraph (d)(1)(E) on the entire unpaved non-haul 

roads leading to a paved public road.

(C) Facilities that pave a minimum of 1⁄4 mile from the rumble grate to 

the facility exit leading to a paved public road.

(D) Facilities that are infrequent mining operations, provided they 

install a rumble grate and apply a gravel pad that meets the criteria 

set forth in subparagraph (d)(1)(E) for a distance of no less than 

100 feet from the rumble grate to the facility exit leading to a 

paved public road, and keep records in accordance with paragraph 

(e)(6). The facility shall inform the District in the case that they 

operate more than 52 days per year based on the average of a 

rolling 3 year period after December 3, 2004. In this case, the 

facility shall comply with the requirements set forth in paragraph 

(d)(8).

(11) The operator of a facility/operation is exempt from using the test methods 

set forth in paragraph (f)(2) for the demonstration of the surface 
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stabilization of open storage piles where 90% of their volume contain 

materials that are larger than 1⁄2 inch product, providing such piles meet the 

performance standards in subparagraph (d)(1)(A).

(i) Alternative Control Options

In lieu of using dust suppressants, the operator of a facility/operation may submit 

for approval by the Executive Officer and the U.S. Environmental Protection 

Agency a plan for achieving equivalent emission reductions through alternative 

control measures.