Construction Permit Exemptions

PURPOSE: This rule lists specific construction or modification projects that are exempt from the requirement to obtain permits to construct under 10 CSR 10-6.060. PUBLISHER’S NOTE: The secretary of state has determined that publication of the entire text of the material that is incorporated by reference as a portion of this rule would be unduly cumbersome or expensive. This material as incorporated by reference in this rule shall be maintained by the agency at its headquarters and shall be made available to the public for inspection and copying at no more than the actual cost of reproduction. This note applies only to the reference material. The entire text of the rule is printed here. (1) Applicability. (A) This rule applies throughout the state of Missouri. However, the exemptions listed in this rule do not apply to a construction or modification meeting any of the conditions in subsection (1)(B) of this rule. (B) The provisions of 10 CSR 10-6.060 apply to any construction or modification which— 1. Is expressly required by an operating permit; or 2. Is subject to federally mandated construction permit ting requirements set forth in sections (7), (8), (9), or any com bination of these, of 10 CSR 10-6.060. (2) Definitions. Definitions for certain terms used in this rule are found in 10 CSR 10-6.060, Construction Permits Required. (3) General Provisions. This section provides exemptions from the requirement to obtain a construction permit. However, when determining whether a construction permit is required and what requirements will be included in the permit under 10 CSR 10-6.060, the emissions of the entire construction or modification, even those portions that meet an exemption under this rule, must be accounted for. The following construction or modifications are exempt from the requirement to obtain a permit under 10 CSR 10-6.060: (A) Sources of Emissions. 1. The following combustion equipment that emits only combustion products and produces less than one hundred fifty (150) pounds per day of any air contaminant: A. Combustion equipment using exclusively natural gas, liquefied petroleum gas, or any combination of these with a heat input capacity of less than ten (10) million British thermal units (Btus) per hour; B. Combustion equipment with a heat input capacity of less than one (1) million Btus per hour; C. Drying or heat-treating ovens with less than ten (10) million Btus per hour heat input capacity provided the oven does not emit pollutants other than the combustion products and the oven is fired exclusively by natural gas, liquefied petroleum gas, or any combination thereof; and D. Oven with a total production of yeast-leavened bakery products of less than ten thousand (10,000) pounds per operating day heated either electrically or exclusively by natural gas firing with a maximum heat input capacity of less than ten (10) million Btus per hour. 2. The following establishments, systems, equipment, and operations: A. Office and commercial buildings, where emissions result solely from space heating by natural or liquefied petroleum gas with a heat input capacity of less than twenty (20) million Btus per hour. Incinerators operated in conjunction with these sources are not exempt unless the incinerator operations are exempt under another section of this rule; B. Comfort air conditioning or comfort ventilating systems not designed or used to control air pollutant emissions; C. Equipment used for any mode of transportation; D. Livestock markets and livestock operations, including animal feeding operations and concentrated animal feeding operations as those terms are defined under 40 CFR 122.23 promulgated as of July 1, 2017, and hereby incorporated by reference in this rule, as published by the Office of the Federal Register. Copies can be obtained from the U.S. Government Publishing Office available at https://bookstore.gpo.gov/ or for mail orders, print and fill out an order form online and mail to U.S. Government Publishing Office, PO Box 979050, St. Louis, MO 63197-9000. This rule does not incorporate any subsequent amendments or additions. In addition, all manure storage and application systems associated with livestock markets or livestock operations that were constructed on or before November 30, 2003, are exempt. This exemption includes any construction or modification of a process, process equipment, emission unit, or air cleaning device after November 30, 2003, unless such change, installation, construction, or reconstruction involves an increase in the operation’s capacity to house or grow animals; E. Grain handling, storage, and drying facility which— (I) Is in noncommercial use only (used only to handle, dry, or store grain produced by the owner or operator) if— (a) The total storage capacity does not exceed seven hundred fifty thousand (750,000) bushels; (b) The grain handling capacity does not exceed four thousand (4,000) bushels per hour; and (c) The facility is located at least five hundred feet (500') from any recreational area, residence, or business not occupied or used solely by the owner or operator; (II) Is in commercial or noncommercial use and— (a) The total storage capacity of the new and any existing facility(ies) does not exceed one hundred ninety thousand (190,000) bushels; (b) Has an installation of additional grain storage capacity in which there is no increase in hourly grain handling capacity and that utilizes existing grain receiving and loadout equipment; or (c) Is a temporary installation used for temporary storage as a result of exceptional events (e.g., natural disasters or abundant harvests exceeding available storage capacity) that meets the following criteria: I. Outside storage structures shall have a crushed lime or concrete floor with retaining walls of either constructed metal or concrete block. These structures may be either oval or round and must be covered with tarps while storing grain. These structures may be filled by portable conveyor or by spouts added from existing equipment; II. Existing buildings may be filled by portable conveyors directly or by overhead fill conveyors that are al ready in the buildings; III. The potential to emit from the storage structures is less than one hundred (100) tons per year of each pollutant; IV. The attainment or maintenance of ambient air quality standards is not threatened; and V. There is no significant impact on any Class I area; F. Restaurants and other retail establishments for the purpose of preparing food for employee and guest consumption; G. Wet sand and gravel production facility that meets the following criteria: (I) Processed materials are obtained from subterra nean and subaqueous beds where the deposits of sand and gravel are consolidated granular materials resulting from nat ural disintegration of rock and stone; (II) Maximum production rate is less than five hundred (500) tons per hour; (III) All permanent roads within the facility are paved and cleaned, or watered, or properly treated with dust-suppressant chemicals as necessary to achieve good engineering control of dust emissions; and (IV) Only natural gas is used as a fuel when drying; H. Equipment solely installed for the purpose of con trolling fugitive dust; I. Equipment or control equipment which eliminates all emissions to the ambient air; J. Equipment, including air pollution control equipment, RESOURCES but not including an anaerobic lagoon, that emits odors but no regulated air pollutants; K. Residential wood heaters, cookstoves, or fireplaces; L. Laboratory equipment used exclusively for chemical and physical analysis or experimentation, except equipment used for controlling radioactive air contaminants; M. Recreational fireplaces; N. Stacks or vents to prevent the escape of sewer gases through plumbing traps for systems handling domestic sewage only. Systems which include any industrial waste do not qualify for this exemption; O. Noncommercial incineration of dead animals, the onsite incineration of resident animals for which no consideration is received or commercial profit is realized as authorized in section 269.020.6, RSMo; P. The following miscellaneous activities: (I) Use of office equipment and products, not including printing establishments or businesses primarily involved in photographic reproduction. This exemption is solely for office equipment that is not part of the manufacturing or production process at the installation; (II) Tobacco smoking rooms and areas; (III) Hand-held applicator equipment for hot melt adhesives with no volatile organic compound (VOC) in the adhesive formula; (IV) Paper trimmers and binders; (V) Blacksmith forges, drop hammers, and hydraulic presses; (VI) Hydraulic and hydrostatic testing equipment; and (VII) Environmental chambers, shock chambers, hu midity chambers, and solar simulators provided no hazardous air pollutants are emitted by the process; Q. The following internal combustion engines: (I) Portable electrical generators that can be moved by hand without the assistance of any motorized or nonmotorized vehicle, conveyance, or device; (II) Spark ignition or diesel fired internal combustion engines used in conjunction with pumps, compressors, pile drivers, welding, cranes, and wood chippers or internal combustion engines or gas turbines of less than two hundred fifty (250) horsepower rating; and (III) Laboratory engines used in research, testing, or teaching; R. The following quarries, mineral processing, and biomass facilities: (I) Drilling or blasting activities; (II) Concrete or aggregate product mixers or pug mills with a maximum rated capacity of less than fifteen (15) cubic yards per hour; (III) Riprap production processes consisting only of a grizzly feeder, conveyors, and storage, not including additional hauling activities associated with riprap production; (IV) Sources at biomass recycling, composting, landfill, publicly owned treatment works (POTW), or related facilities specializing in the operation of, but not limited to, tub grinders powered by a motor with a maximum output rating of ten (10) horsepower; hoggers, shredders, and similar equipment powered by a motor with a maximum output rating of twentyfive (25) horsepower; and other sources at such facilities with a total throughput less than five hundred (500) tons per year; and (V) Land farming of soils contaminated only with petroleum fuel products where the farming beds are located a minimum of three hundred feet (300') from the property boundary; S. The following kilns and ovens: (I) Kilns with a firing capacity of less than ten (10) million Btus per hour used for firing ceramic ware, heated exclusively by natural gas, liquefied petroleum gas, electricity, or any combination thereof; and (II) Electric ovens or kilns used exclusively for curing or heat-treating provided no hazardous air pollutants (HAPs) or VOCs are emitted; T. The following food and agricultural equipment: (I) Equipment used in agricultural operations to grow crops; (II) Equipment used exclusively to slaughter animals. This exemption does not apply to other slaughterhouse equipment such as rendering cookers, boilers, heating plants, incinerators, and electrical power generating equipment; (III) Commercial smokehouses or barbecue units in which the maximum horizontal inside cross-sectional area does not exceed twenty (20) square feet; (IV) Equipment used exclusively to grind, blend, package, or store tea, cocoa, spices, or coffee; (V) Equipment with the potential to dry, mill, blend, grind, or package less than one thousand (1,000) pounds per year of dry food products such as seeds, grains, corn, meal, flour, sugar, and starch; (VI) Equipment with the potential to convey, transfer, clean, or separate less than one thousand (1,000) tons per year of dry food products or waste from food production operations; (VII) Storage equipment or facilities containing dry food products that are not vented to the outside atmosphere or which have the potential to handle less than one thousand (1,000) tons per year; (VIII) Coffee, cocoa, and nut roasters with a roasting capacity of less than fifteen (15) pounds of beans or nuts per hour, and stoners or coolers operated with these roasters; (IX) Containers, reservoirs, tanks, or loading equipment used exclusively for the storage or loading of beer, wine, or other alcoholic beverages produced for human consumption; (X) Brewing operations at facilities with the potential to produce less than three (3) million gallons of beer per year; and (XI) Fruit sulfuring operations at facilities with the potential to produce less than ten (10) tons per year of sulfured fruits and vegetables; U. Batch solvent recycling equipment provided the recovered solvent is used primarily on-site, the maximum heat input is less than one (1) million Btus per hour, the batch capacity is less than one hundred fifty (150) gallons, and there are no solvent vapor leaks from the equipment which exceed five hundred (500) parts per million; V. The following surface coating and printing operations: (I) Batch mixing of inks, coatings, or paints provided— (a) The operations do not occur at an ink, coatings, or paint manufacturing facility; (b) Good housekeeping is practiced, spills are cleaned up as soon as possible, equipment is maintained ac cording to manufacturer’s instruction, and property is kept clean; (c) All waste inks, coating, and paints are disposed of properly; and (d) Prior to disposal, all liquid waste is stored in covered containers; (II) Any powder coating operation, or radiation cured coating operation where ultraviolet or electron beam energy is used to initiate a reaction to form a polymer network; (III) Any surface-coating source that employs solely nonrefillable hand-held aerosol cans; and (IV) Surface coating operations utilizing powder coating materials with the powder applied by an electrostatic powder spray gun or an electrostatic fluidized bed; W. The following metal working and handling equipment: (I) Carbon dioxide (CO2) lasers, used only on metals and other materials that do not emit a HAP or VOC in the process; (II) Laser trimmers equipped with dust collection attachments; (III) Equipment used for pressing or storing sawdust, wood chips, or wood shavings; (IV) Equipment used exclusively to mill or grind coatings and molding compounds in a paste form provided the solution contains less than one percent (1%) VOC by weight; (V) Tumblers used for cleaning or deburring metal products without abrasive blasting; (VI) Batch mixers with a rated capacity of fifty-five (55) gallons or less provided the process will not emit hazardous air pollutants; (VII) Equipment used exclusively for the mixing and blending of materials at ambient temperature to make waterbased adhesives provided the process will not emit hazardous air pollutants; (VIII) Equipment used exclusively for the packaging of lubricants or greases; (IX) Platen presses used for laminating provided the process will not emit hazardous air pollutants; (X) Roll mills or calendars for rubber or plastics provided the process will not emit hazardous air pollutants; (XI) Equipment used exclusively for the melting and applying of wax containing less than one percent (1%) VOC by weight; (XII) Equipment used exclusively for the conveying and storing of plastic pellets; and (XIII) Solid waste transfer stations that receive or load out less than fifty (50) tons per day of nonhazardous solid waste; X. The following liquid storage and loading equipment: (I) Storage tanks and vessels having a capacity of less than five hundred (500) gallons; and (II) Tanks, vessels, and pumping equipment used exclusively for the storage and dispensing of any aqueous solution which contains less than one percent (1%) by weight of organic compounds. Tanks and vessels storing the following materials are not exempt: (a) Sulfuric or phosphoric acid with an acid strength of more than ninety-nine percent (99.0%) by weight; (b) Nitric acid with an acid strength of more than seventy percent (70.0%) by weight; (c) Hydrochloric or hydrofluoric acid with an acid strength of more than thirty percent (30.0%) by weight; or (d) More than one (1) liquid phase, where the top phase contains more than one percent (1%) VOC by weight; Y. The following chemical processing equipment or operations: (I) Storage tanks, reservoirs, pumping, and handling equipment, and mixing and packaging equipment containing or processing soaps, vegetable oil, grease, animal fat, and nonvolatile aqueous salt solutions, provided appropriate lids and covers are utilized; and (II) Batch loading and unloading of solid phase catalysts; Z. Body repair and refinishing of motorcycles, passenger cars, vans, light trucks, heavy trucks, and other vehicle body parts, bodies, and cabs, provided— (I) Good housekeeping is practiced; spills are cleaned up as soon as possible, equipment is maintained according to manufacturers’ instructions, and property is kept clean. All waste coatings, solvents, and spent automotive fluids including, but not limited to, fuels, engine oil, gear oil, transmission fluid, brake fluid, antifreeze, fresh or waste fuels, and spray booth filters or water wash sludge are disposed of properly. Prior to disposal, all liquid waste shall be stored in covered containers. In addition, all solvents and cleaning materials shall be stored in closed containers; (II) All spray coating operations shall be performed in a totally enclosed filtered spray booth or totally enclosed filtered spray area with an air intake area of less than one hundred (100) square feet. All spray areas shall be equipped with a running fan during spraying, and the exhaust air shall either be vented through a stack to the atmosphere or recirculated back into the shop through a carbon adsorption system. All carbon adsorption systems shall be properly maintained according to the manufacturer’s operating instructions, and the carbon shall be replaced at the manufacturer’s recommended intervals to minimize solvent emissions; and (III) Spray booth, spray area, and preparation area stacks shall be located at least eighty (80) feet away from any residence, recreation area, church, school, child care facility, or medical or dental facility; AA. Sawmills processing no more than twenty-five (25) million board feet, green lumber tally of wood per year, in which no mechanical drying of lumber is performed, in which fine particle emissions are controlled through the use of properly engineered baghouses or cyclones, and which meet all of the following provisions: (I) The mill shall be located at least five hundred feet (500') from any recreational area, school, residence, or other structure not occupied or used solely by the owner or operator of the facility or the owner of the property upon which the installation is located; (II) All sawmill residues (sawdust, shavings, chips, bark) from debarking, planing, saw areas, etc. shall be removed or contained to minimize fugitive particulate emissions. Spillage of wood residues shall be cleaned up as soon as possible and contained such that dust emissions from wind erosion and/ or vehicle traffic are minimized. Disposal of collected sawmill residues must be accomplished in a manner that minimizes residues becoming airborne. Disposal by means of burning is prohibited unless it is conducted in a permitted incinerator; and (III) All open-bodied vehicles transporting sawmill residues (sawdust, shavings, chips, bark) shall be covered with a tarp to achieve maximum control of particulate emissions; BB. Internal combustion engines and gas turbine driven compressors, electric generator sets, and water pumps, used only for portable or emergency services, provided that the maximum annual operating hours shall not exceed five hun dred (500) hours. Emergency generators are exempt only if the emergency generator(s) meet the conditions listed in parts (3) (A)2.BB.(I), (3)(A)2.BB.(II), and (3)(A)2.BB.(III) along with one (1) or both conditions listed in parts (3)(A)2.BB.(IV) and (3)(A)2.BB.(V) below: (I) The sole function of the emergency generator(s) is to provide backup power when electric power from the local utility is interrupted; and (II) The emergency generator(s) are equipped with a non-resettable meter to measure the hours of operation; and RESOURCES (III) The emergency generator(s) are operated only during emergency situations and for short periods of time to perform maintenance and operational readiness testing; and (IV) There is only one (1) emergency generator included in the construction or modification; or (V) The combined potential emissions of all generators included in the construction or modification are less than or equal to the levels specified in subparagraphs (3)(A)3.A. and (3) (A)3.B.; CC. Commercial dry cleaners; and DD. Carving, cutting, routing, turning, drilling, machining, sawing, sanding, planing, buffing, or polishing solid materials, other than materials containing any asbestos, beryllium, or lead greater than one percent (1%) by weight as determined by Material Safety Data Sheets (MSDS), vendor material specifications and/or purchase order specifications, where equipment— (I) Directs a stream of liquid at the point where material is processed; (II) Is used only for maintenance or support activity not conducted as part of the installation’s primary business activity; (III) Is exhausted inside a building; or (IV) Is ventilated externally to an operating cyclonic inertial separator (cyclone), baghouse, or dry media filter. Other particulate control devices such as electrostatic precipitators or scrubbers are subject to construction permitting or a permitby-rule, unless otherwise exempted. 3. Construction or modifications that, when considered in their entirety, meet the requirements of subparagraph (3) (A)3.B. of this rule for each hazardous air pollutant; and that meet the requirements of either subparagraph (3)(A)3.A. or the requirements of both subparagraphs (3)(A)3.C. and (3) (A)3.D. of this rule for each criteria pollutant. The director may require review of construction or modifications otherwise exempt under paragraph (3)(A)3. of this rule if the emissions of the proposed construction or modification will appreciably affect air quality or the air quality standards are appreciably exceeded or complaints involving air pollution have been filed in the vicinity of the proposed construction or modification. Owners or operators using an exemption pursuant to this paragraph are subject to the reporting and recordkeeping provisions specified in section (4) of this rule. A. At maximum design capacity the proposed construction or modification shall emit each pollutant at a rate of no more than the amount specified in Table 1. TABLE 1. Insignificant Emission Exemption Levels Pollutant Insignificance Level (lbs per hr) Particulate Matter 10 Micron (PM10) (Emitted solely by equipment) 1.0 Sulfur Dioxide (SO2) 2.75 Nitrogen Oxides (NOX) 2.75 Volatile Organic Compounds (VOCs) 2.75 Carbon Monoxide (CO) 6.88 B. At maximum design capacity, the proposed construc tion or modification will emit a hazardous air pollutant at a rate of no more than one-half (0.5) pound per hour, or the screening model action level (SMAL) as established in subpara graph (5)(F)6.A. of 10 CSR 10-6.060, whichever is less. C. Actual emissions of each criteria pollutant will be no more than eight hundred seventy-six (876) pounds per year. D. Actual emissions of volatile organic compounds that do not contain hazardous air pollutants will be no more than four (4) tons per year. (B) Activities. Any activity that is— 1. Routine maintenance, parts replacement, or relocation of emission units within the same installation which do not involve either any appreciable change either in the quality or nature, or any increase in either the potential to emit or the effect on air quality, of the emissions of any air contaminant. Some examples are as follows: A. Replacing the bags in a baghouse; B. Replacing wires, plates, rappers, controls, or electric circuitry in an electrostatic precipitator which does not measurably decrease the design efficiency of the unit; C. Replacing fans, pumps, or motors which do not alter the operation of a source or performance of a control device; D. Replacing boiler tubes; E. Replacing piping, hoods, and ductwork; and F. Replacing engines, compressors, or turbines as part of a normal maintenance program; 2. Changes in a process or process equipment which do not involve the construction or modification of an emissions unit or associated air cleaning devices, and that do not involve either any appreciable change either in the quality or nature or any increase in either the potential to emit or the effect on air quality of the emissions of any air contaminant. Some examples are as follows: A. Changing supplier or formulation of similar raw materials, fuels, paints, and other coatings; B. Changing the sequence of the process; C. Changing the method of raw material addition; D. Changing the method of product packaging; E. Changing the process operating parameters; F. Replacing an identical or more efficient cyclone precleaner which is used as a precleaner in a fabric filter control system; G. Installing a floating roof on an open-top petroleum storage tank; H. Replacing a fuel burner in a boiler with a more thermally efficient burner; I. Lengthening a paint drying oven to provide additional curing time; and J. Changes in the location, within the storage area, or configuration of a material storage pile or material handling equipment; 3. Replacement of like-kind emission units that do not involve either any appreciable change either in the quality or nature, or any increase either in the potential to emit or the effect on air quality, of the emissions of any air contaminant; 4. The exempt activities in paragraphs (3)(B)1.–3. of this rule reflect a presumption that existing emission units which are changed or replaced by like-kind units shall be treated as having begun normal operation for purposes of determining actual emissions; 5. The following miscellaneous activities: A. Plant maintenance and upkeep activities such as routine cleaning, janitorial services, use of janitorial products, groundskeeping, general repairs, architectural or maintenance painting, welding repairs, plumbing, roof repair, installing insulation, using air compressors and pneumatically operated equipment, and paving parking lots, provided these activities are not conducted as part of the installation’s primary business activity; B. Batteries and battery charging stations; C. Fire suppression equipment and emergency road flares; D. Laundry activities, except dry-cleaning and steam boilers; and E. Steam emissions from leaks, safety relief valves, steam cleaning operations, and steam sterilizers; and 6. The following miscellaneous surface preparation and cleaning activities: A. Equipment and containers used for surface preparation, cleaning, or stripping by use of solvents or solutions that meet all of the following: (I) Solvent used must have an initial boiling point of greater than three hundred two degrees Fahrenheit (302°F), and this initial boiling point must exceed the maximum operating temperature by at least one hundred eighty degrees Fahrenheit (180°F); (II) The equipment or container has a capacity of less than thirty-five (35) gallons of liquid. For remote reservoir cold cleaners, capacity is the volume of the remote reservoir; (III) The equipment or container has a liquid surface area less than seven (7) square feet, or for remote reservoir cold cleaners, the sink or working area has a horizontal surface less than seven (7) square feet; (IV) Solvent flow must be limited to a continuous fluid stream type arrangement. Fine, atomized, or shower type sprays are not exempt; and (V) All lids and closures are properly employed; B. The exclusion in subparagraph (3)(B)6.A. of this rule does not apply to solvent wipe cleaning operations; C. Abrasive blasting sources that have a confined volume of less than one hundred (100) cubic feet and are controlled by a particulate filter; D. Blast cleaning equipment using a suspension of abrasive in water; E. Portable blast cleaning equipment for use at any single location for less than sixty (60) days; and F. Any solvent cleaning or surface preparation source that employs only non-refillable handheld aerosol cans. (4) Reporting and Recordkeeping. Owners or operators using an exemption in paragraph (3)(A)3. of this rule shall maintain records in sufficient detail to show compliance with the exemptions in paragraph (3)(A)3. of this rule. Any noncompliance with the requirements in this paragraph constitutes a violation and is grounds for enforcement action and the exemption will no longer apply. Owners or operators of installations found to be not in compliance with the requirements of this paragraph shall be required to apply for a construction permit under 10 CSR 10-6.060. Recordkeeping shall begin on the date of the construction or modification. The exemptions shall be documented by maintaining records or documentation to prove that the criteria described in subsection (4)(A) and either subsection (4)(B) or subsection (4) (C) of this rule are met. (A) Potential emissions are below the levels listed in subparagraph (3)(A)3.B. of this rule. (B) If using the criteria in subparagraph (3)(A)3.A. of this rule to meet the exemption, the records or documentation must be sufficient to prove that potential hourly emissions are below the levels listed in subparagraph (3)(A)3.A. of this rule. (C) If using the criteria in subparagraphs (3)(A)3.C. and (3) (A)3.D. of this rule to meet the exemption, the records must be sufficient to prove that actual emissions are below the exemp tion threshold levels listed in subparagraphs (3)(A)3.C. and (3) (A)3.D. of this rule. (5) Test Methods. (Not Applicable) AUTHORITY: section 643.050, RSMo Supp. 2025.* Original rule filed March 5, 2003, effective Oct. 30, 2003. Amended: Filed July 1, 2004, effective Feb. 28, 2005. Amended: Filed Dec. 1, 2005, effective July 30, 2006. Amended: Filed Oct. 1, 2008, effective May 30, 2009. Amended: Filed Nov. 25, 2019, effective Sept. 30, 2020. Amended: Filed May 15, 2025, effective Jan. 30, 2026. *Original authority: 643.050, RSMo 1965, amended 1972, 1992, 1993, 1995, 2011, 2022.