Browse: Departments   Dates   Agencies  

CFR Citation: 40 CFR Part 63

EPA ID: [EPA-HQ-OAR-2006-0306; FRL-8547-2]

RIN ID: RIN 2060-AO27

NOTICE: Part II

DOCUMENT ACTION: Proposed rule.

SUBJECT CATEGORY: National Emission Standards for Hazardous Air Pollutants: Area Source Standards for Nine Metal Fabrication and Finishing Source Categories

DATES: Comments must be received on or before May 5, 2008, unless a public hearing is requested by April 14, 2008. If a hearing is requested on this proposed rule, written comments must be received by May 19, 2008. Under the Paperwork Reduction Act, comments on the information collection provisions must be received by OMB on or before May 5, 2008.

DOCUMENT SUMMARY: EPA is proposing national emission standards for control of hazardous air pollutants (HAP) for nine metal fabrication and finishing area source categories. This rule proposes emission standards in the form of management practices and equipment standards for new and existing operations of dry abrasive blasting, machining, dry grinding and dry polishing with machines, spray painting and other spray coating, and welding operations. These proposed standards reflect EPA's determination regarding the generally achievable control technology (GACT) and/or management practices for the nine area source categories.

SUMMARY: Environmental Protection Agency,

SUPPLEMENTAL INFORMATION

Outline. The information in this preamble is organized as follows: I. General Information

A. Does this action apply to me?

B. What should I consider as I prepare my comments to EPA?

C. Where can I get a copy of this document?

D. When would a public hearing occur?
II. Background Information for Proposed Area Source Standards

A. What is the statutory authority and regulatory approach for the proposed standards?

B. What source categories are affected by the proposed standards?

C. What are the production operations, emission sources, and available controls?

III. Summary of Proposed Standards

A. Do the proposed standards apply to my source?

B. When must I comply with the proposed standards?

C. For what processes is EPA proposing standards?

D. What emissions control requirements is EPA proposing?

E. What are the initial compliance provisions?

F. What are the continuous compliance requirements?

G. What are the notification, recordkeeping, and reporting requirements?
IV. Rationale for This Proposed Rule

A. How did we select the source category?

B. How did we select the affected sources?

C. How did we determine the regulated processes?

D. How was GACT determined?

E. How did we select the compliance requirements?

F. How did we decide to exempt this area source category from title V permit requirements?
V. Impacts of the Proposed Standards

A. What are the air impacts?

B. What are the cost impacts?

C. What are the economic impacts?

D. What are the nonair health, environmental, and energy impacts?

VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act
[[Page 18335]]

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer Advancement Act

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and LowIncome Populations
I. General Information

A. Does this action apply to me?

The regulated categories and entities potentially affected by this proposed action are shown in the table below. This proposed rule applies only to facilities that are an area source of the compounds of cadmium, chromium, lead, manganese, and nickel, or an area source of volatile organic HAP (VOHAP) from spray painting operations, and which perform metal fabrication or finishing operations in one of the following nine source categories: (1) Electrical and Electronic Equipment Finishing Operations; (2) Fabricated Metal Products; (3) Fabricated Plate Work (Boiler Shops); (4) Fabricated Structural Metal Manufacturing; (5) Heating Equipment, except Electric; (6) Industrial Machinery and Equipment: Finishing Operations; (7) Iron and Steel Forging; (8) Primary Metal Products Manufacturing; and (9) Valves and Pipe Fittings. Facilities affected by this proposed rule are not subject to the miscellaneous coating requirements in 40 CFR part 63, subpart HHHHHH, ``National Emission Standards for Hazardous Air Pollutants: Paint Stripping and Miscellaneous Surface Coating Operations at Area Sources,'' for their affected source(s) that are subject to the requirements of this proposed rule. There potentially may be other sources at the facility not subject to the requirements of this proposed rule that are instead subject to subpart HHHHHH of this part.
Metal fabrication and Examples of Regulated finishing category NAICS Codes\1\ Entities Electrical and Electronics 335999........... Establishments Equipment Finishing primarily engaged in Operations. manufacturing motors and generators and electrical machinery, equipment, and supplies, not elsewhere classified. The electrical machinery equipment and supplies industry sector includes facilities primarily engaged in high energy particle acceleration systems and equipment, electronic simulators, appliance and extension cords, bells and chimes, insect traps, and other electrical equipment and supplies, not elsewhere classified. The Motors and Generators Manufacturing industry sector includes those establishments primarily engaged in manufacturing electric motors (except engine starting motors) and power generators; motor generator sets; railway motors and control equipment; and motors, generators and control equipment for gasoline, electric, and oilelectric buses and trucks. Fabricated Metal Products..... 332117........... Establishments primarily engaged in manufacturing fabricated metal products, such as fire or burglary resistive steel safes and vaults and similar fire or burglary resistive products; and collapsible tubes of thin flexible metal. Also included are establishments primarily engaged in manufacturing powder metallurgy products, metal boxes; metal ladders; metal household articles, such as ice cream freezers and ironing boards; and other fabricated metal products not elsewhere classified. Fabricated Plate Work (Boiler 332313, 332410, Establishments Shops). 332420. primarily engaged in manufacturing power and marine boilers, pressure and nonpressure tanks, processing and storage vessels, heat exchangers, weldments and similar products. Fabricated Structural Metal 332312........... Establishments Manufacturing. primarily engaged in fabricating iron and steel or other metal for structural purposes, such as bridges, buildings, and sections for ships, boats, and barges. Heating Equipment, except 333414........... Establishments Electric. primarily engaged in manufacturing heating equipment, except electric and warm air furnaces, including gas, oil, and stoker coal fired equipment for the automatic utilization of gaseous, liquid, and solid fuels. Typical products produced in this source category include lowpressure heating (steam or hot water) boilers, fireplace inserts, domestic (steam or hot water) furnaces, domestic gas burners, gas room heaters, gas infrared heating units, combination gasoil burners, oil or gas swimming pool heaters, heating apparatus (except electric or warm air), kerosene space heaters, gas fireplace logs, domestic and industrial oil burners, radiators (except electric), galvanized iron nonferrous metal range boilers, room heaters (except electric), coke and gas burning salamanders, liquid or gas solar energy collectors, solar heaters, space heaters (except electric), mechanical (domestic and industrial) stokers, wood and coalburning stoves, domestic unit heaters (except electric), and wall heaters (except electric). [[Page 18336]]
Industrial Machinery and 333120, 333132, Establishments Equipment: Finishing 333911. primarily engaged in Operations. construction machinery manufacturing, oil and gas field machinery manufacturing, and pumps and pumping equipment manufacturing. Finishing operations include the collection of all operations associated with the surface coating of industrial machinery and equipment. The construction machinery manufacturing industry sector includes establishments primarily engaged in manufacturing heavy machinery and equipment of types used primarily by the construction industries, such as bulldozers; concrete mixers; cranes, except industrial plan overhead and trucktype cranes; dredging machinery; pavers; and power shovels. Also included in this industry are establishments primarily engaged in manufacturing forestry equipment and certain specialized equipment, not elsewhere classified, similar to that used by the construction industries, such as elevating platforms, ship cranes and capstans, aerial work platforms, and automobile wrecker hoists. The oil and gas field machinery manufacturing industry sector includes establishments primarily engaged in manufacturing machinery and equipment for use in oil and gas field or for drilling water wells, including portable drilling rigs. The pumps and pumping equipment industry sector includes establishments primarily engaged in manufacturing pumps and pumping equipment for general industrial, commercial, or household use, except fluid power pumps and motors. This category includes establishments primarily engaged in manufacturing domestic water and sump pumps. Iron and Steel Forging........ 33211............ Establishments primarily engaged in the forging manufacturing process, where purchased iron and steel metal is pressed, pounded or squeezed under great pressure into high strength parts known as forgings. The process is usually performed hot by preheating the metal to a desired temperature before it is worked. The forging process is different from the casting and foundry processes, as metal used to make forged parts is never melted and poured. Primary Metals Products 332618........... Establishments Manufacturing. primarily engaged in manufacturing products such as fabricated wire products (except springs) made from purchased wire. These facilities also manufacture steel balls; nonferrous metal brads and nails; nonferrous metal spikes, staples, and tacks; and other primary metals products not elsewhere classified. Valves and Pipe Fittings...... 332919........... Establishments primarily engaged in manufacturing metal valves and pipe fittings; flanges; unions, with the exception of purchased pipes; and other valves and pipe fittings not elsewhere classified. \1\North American Industry Classification System.

This table is not intended to be exhaustive, but rather provide a guide for readers regarding entities likely to be affected by this action. To determine whether your facility would be regulated by this action you can refer to the descriptions in section (II)(B) below. For descriptions of the North American Industry Classification System (NAICS) codes, you can view information on the U.S. Census site at http://www.census.gov/epcd/ec97brdg. If you have any questions regarding the applicability of this action to a particular entity, consult either the air permit authority for the entity or your EPA regional representative as listed in 40 CFR 63.13 of subpart A (General Provisions).

B. What should I consider as I prepare my comments to EPA?

Do not submit information containing CBI to EPA through http:// www.regulations.gov or email. Send or deliver information identified as CBI only to the following address: Roberto Morales, OAQPS Document Control Officer (C40402), Environmental Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711, Attention Docket ID EPAHQOAR20060306. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CDROM that you mail to EPA, mark the outside of the disk or CDROM as CBI and then identify electronically within the disk or CDROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

C. Where can I get a copy of this document?

In addition to being available in the docket, an electronic copy of this proposed action will also be available on the Worldwide Web (WWW) through EPA's Technology Transfer Network (TTN). A copy of this proposed action will be posted on the TTN's policy and guidance page for newly proposed or promulgated rules at the following address: http://www.epa.gov/ttn/oarpg/. The TTN provides information and technology exchange in various areas of air pollution control. D. When would a public hearing occur?

If anyone contacts EPA requesting to speak at a public hearing concerning this proposed rule by April 14, 2008, we will hold a public hearing on April 18, 2008. If you are interested in attending the public hearing, contact Ms. Pamela Garrett at (919) 5417966 to verify that a hearing will be held. If a public hearing is held, it will be held at 10 a.m.
[[Page 18337]]
at the EPA's Environmental Research Center Auditorium, Research Triangle Park, NC, or an alternate site nearby.
II. Background Information for Proposed Area Source Standards A. What is the statutory authority and regulatory approach for the proposed standards?

Section 112(d) of the CAA requires us to establish national emission standards for hazardous air pollutants (NESHAP) for both major and area sources of HAP that are listed for regulation under CAA section 112(c). A major source emits or has the potential to emit 10 tons per year (tpy) or more of any single HAP or 25 tpy or more of any combination of HAP. An area source is a stationary source that is not a major source.

Section 112(k)(3)(B) of the CAA calls for EPA to identify at least 30 HAP which, as the result of emissions from area sources, pose the greatest threat to public health in the largest number of urban areas. EPA implemented this provision in 1999 in the Integrated Urban Air Toxics Strategy (64 FR 38715, July 19, 1999). Specifically, in the Strategy, EPA identified 30 HAP that pose the greatest potential health threat in urban areas, and these HAP are referred to as the ``30 urban HAP.'' Section 112(c)(3) requires EPA to list sufficient categories or subcategories of area sources to ensure that area sources representing 90 percent of the emissions of the 30 urban HAP are subject to regulation. We implemented these requirements through the Integrated Urban Air Toxics Strategy (64 FR 38715, July 19, 1999). A primary goal of the Strategy is to achieve a 75 percent reduction in cancer incidence attributable to HAP emitted from stationary sources.

Under CAA section 112(d)(5), we may elect to promulgate standards or requirements for area sources ``which provide for the use of GACT or management practices by such sources to reduce emissions of hazardous air pollutants.'' Additional information on GACT is found in the Senate report on the legislation (Senate Report Number 101228, December 20, 1989), which describes GACT as:
* * * methods, practices and techniques which are commercially available and appropriate for application by the sources in the category considering economic impacts and the technical capabilities of the firms to operate and maintain the emissions control systems. Consistent with the legislative history, we can consider costs and economic impacts in determining GACT, which is particularly important when developing regulations for source categories that may have many small businesses.

Determining what constitutes GACT involves considering the control technologies and management practices that are generally available to the area sources in the source category. We also consider the standards applicable to major sources in the same industrial sector to determine if the control technologies and management practices are transferable and generally available to area sources. In appropriate circumstances, we may also consider technologies and practices at area and major sources in similar categories to determine whether such technologies and practices could be considered generally available for the area source category at issue. Finally, as noted above, in determining GACT for a particular area source category, we consider the costs and economic impacts of available control technologies and management practices on that category.

We are proposing these national emission standards in response to a courtordered deadline that requires EPA to issue standards for 11 source categories listed pursuant to section 112(c)(3) and (k) by June 15, 2008 (Sierra Club v. Johnson, no. 011537, D.D.C., March 2006). We have already issued regulations addressing one of the 11 area source categories. See regulations for Wood Preserving (Federal Register, 72 (135), July 16, 2007.) Other rulemakings will include standards for the remaining source categories that are due in June 2008.
B. What source categories are affected by these proposed standards?

These proposed standards would affect any facility that performs metal fabrication or finishing operations in one of the following nine metal fabrication and finishing area source categories: (1) Electrical and Electronic Equipment Finishing Operations; (2) Fabricated Metal Products; (3) Fabricated Plate Work (Boiler Shops); (4) Fabricated Structural Metal Manufacturing; (5) Heating Equipment, except Electric; (6) Industrial Machinery and Equipment: Finishing Operations; (7) Iron and Steel Forging; (8) Primary Metal Products Manufacturing; and (9) Valves and Pipe Fittings. Throughout this proposed rule, we refer to the nine metal fabrication and finishing source categories collectively as ``metal fabrication or finishing operations.''

The following are descriptions of the nine metal fabrication and finishing source categories:

Electrical and Electronic Equipment Finishing Operations: This category includes establishments primarily engaged in manufacturing motors and generators and electrical machinery, equipment, and supplies, not elsewhere classified, and includes facilities primarily engaged in high energy particle acceleration systems and equipment, electronic simulators, appliance and extension cords, bells and chimes, insect traps, and other electrical equipment and supplies not elsewhere classified. This category also includes those establishments primarily engaged in manufacturing electric motors (except engine starting motors) and power generators; motor generator sets; railway motors and control equipment; and motors, generators and control equipment for gasoline, electric, and oilelectric buses and trucks.

Fabricated Metal Products, Not Elsewhere Classified: This category includes establishments primarily engaged in manufacturing fabricated metal products, such as fire or burglary resistive steel safes and vaults and similar fire or burglary resistive products; and collapsible tubes of thin flexible metal. Also included are establishments primarily engaged in manufacturing powder metallurgy products, metal boxes; metal ladders; metal household articles, such as ice cream freezers and ironing boards; and other fabricated metal products not elsewhere classified.

Fabricated Plate Work (Boiler Shops): This category includes establishments primarily engaged in manufacturing power and marine boilers, pressure and nonpressure tanks, processing and storage vessels, heat exchangers, weldments and similar products.

Fabricated Structural Metal Manufacturing: This category includes establishments primarily engaged in fabricating iron and steel or other metal for structural purposes, such as bridges, buildings, and sections for ships, boats, and barges.

Heating Equipment, except Electric: This category includes establishments primarily engaged in manufacturing heating equipment, except electric and warm air furnaces, including gas, oil, and stoker coal fired equipment for the automatic utilization of gaseous, liquid, and solid fuels. Typical products produced in this source category include lowpressure heating (steam or hot water) boilers, fireplace inserts, domestic (steam or hot water) furnaces, domestic gas burners, gas room heaters, gas infrared heating units, combination gasoil burners, oil or gas swimming pool heaters, heating apparatus (except electric or warm air), kerosene space heaters, gas fireplace logs, domestic and industrial oil burners, radiators (except
[[Page 18338]]
electric), galvanized iron nonferrous metal range boilers, room heaters (except electric), coke and gas burning salamanders, liquid or gas solar energy collectors, solar heaters, space heaters (except electric), mechanical (domestic and industrial) stokers, wood and coal burning stoves, domestic unit heaters (except electric), and wall heaters (except electric).

Industrial Machinery and Equipment Finishing Operations: This category includes establishments primarily engaged in construction machinery manufacturing, oil and gas field machinery manufacturing, and pumps and pumping equipment manufacturing. Finishing operations include the collection of all operations associated with the surface coating of industrial machinery and equipment. This category includes establishments primarily engaged in manufacturing heavy machinery and equipment of types used primarily by the construction industries, such as bulldozers; concrete mixers; cranes, except industrial plant overhead and trucktype cranes; dredging machinery; pavers; and power shovels. Also included in this industry are establishments primarily engaged in manufacturing forestry equipment and certain specialized equipment, not elsewhere classified, similar to that used by the construction industries, such as elevating platforms, ship cranes and capstans, aerial work platforms, and automobile wrecker hoists. This category also includes establishments primarily engaged in manufacturing machinery and equipment for use in oil and gas fields or for drilling water wells, including portable drilling rigs. This category includes establishments primarily engaged in manufacturing pumps and pumping equipment for general industrial, commercial, or household use, except fluid power pumps and motors, and establishments primarily engaged in manufacturing domestic water and sump pumps.

Iron and Steel Forging: This category includes establishments primarily engaged in the forging manufacturing process, where purchased iron and steel metal is pressed, pounded or squeezed under great pressure into high strength parts known as forgings. The process is usually performed hot by preheating the metal to a desired temperature before it is worked. The forging process is different from the casting and foundry processes, as metal used to make forged parts is never melted and poured.

Primary Metal Products Manufacturing: This source category includes establishments primarily engaged in manufacturing products such as fabricated wire products (except springs) made from purchased wire. These facilities also manufacture steel balls; nonferrous metal brads and nails; nonferrous metal spikes, staples, and tacks; and other primary metals products not elsewhere classified.

Valves and Pipe Fittings: This source category includes establishments primarily engaged in manufacturing metal valves and pipe fittings, flanges, and unions, with the exception of from purchased pipes; and other valves and pipe fitting products not elsewhere classified.

We added the nine metal fabrication and finishing source categories to the Integrated Urban Air Toxics Strategy Area Source Category List on November 22, 2002 (67 FR 70427). The inclusion of these source categories to the section 112(c)(3) area source category list is based on 1990 emissions data, as EPA used 1990 as the baseline year for that listing. The nine metal fabrication and finishing source categories were listed for regulation based on emissions of compounds of cadmium, chromium, lead, manganese, and nickel in the 1990 inventory, hereafter referred to as ``metal fabrication and finishing metal HAP'' (MFHAP). Four of the metal fabrication and finishing source categories were also listed for emissions of the organic HAP trichloroethylene (TCE).\1\ Chlorinated solvents such as TCE are used as degreasers in these metal fabrication and finishing source categories. We subsequently discovered that the 1990 emissions data for TCE was for metal fabrication and finishing facilities that used TCE in degreasing operations, which are not part of this source category. Rather, these emission units at both major and area sources are subject to standards for halogenated solvent cleaning under 40 CFR part 63, subpart T. Consequently, we are not proposing standards for TCE from metal fabrication and finishing facilities. The four metal fabrication and finishing source categories listed for TCE emissions remain listed source categories pursuant to section 112(c)(3) of this part. Therefore, we are clarifying that we do not need these four source categories to meet the section 112(c)(3) 90 percent requirement regarding area source emissions of TCE. \1\ These four source categories were Electrical and Electronic Equipment Finishing Operations; Fabricated Metal Products; Primary Metal Products Manufacturing; and Valves and Pipe Fittings.

Based on 2002 U.S. Census data and a survey of the industry that we conducted in 2006, we estimate that 5,800 metal fabrication and finishing area source facilities are currently operating in the U.S. Our analyses of 2002 U.S. Census data also indicate that more than 90 percent of the metal fabrication and finishing area source categories is comprised of small businesses, based on the Small Business Administration definition.

A majority of the metal fabrication and finishing area source facilities are estimated to be in urban areas, based on an estimate of 73 percent developed from EPA's 2002 National Emission Inventory (NEI).\2\
\2\ These urban areas are defined to be the urban 1 and urban 2 areas that formed the basis of the listing decisions under 112(c)(3) and (k).

Facilities affected by this proposed rule are not subject to the miscellaneous coating requirements in 40 CFR part 63, subpart HHHHHH, ``National Emission Standards for Hazardous Air Pollutants: Paint Stripping and Miscellaneous Surface Coating Operations at Area Sources,'' for their affected source(s) that are subject to the requirements of this proposed rule. There potentially may be other sources at the facility not subject to the requirements of this proposed rule that are instead subject to subpart HHHHHH of this part. C. What are the production operations, emission sources, and available controls?

While these nine source categories produce a wide variety of products, they perform very similar fabrication and finishing operations to create them. There are five general production operations common to metal fabrication and finishing source categories that can emit MFHAP. These five production operations are: (1) Dry abrasive blasting; (2) dry grinding and dry polishing with machines; (3) machining; (4) spray painting and coating; and (5) welding.

As typical within any industry, there is variation in operations between facilities. Also, all facilities do not necessarily employ all five production areas. Information acquired from an EPA survey of 166 facilities showed that for the area sources in the source categories of interest, 39 percent perform dry abrasive blasting, 59 percent perform metal fabrication and finishing with machines, 60 percent perform painting or coating of some kind (that includes but is not limited to spray painting or spray coating), and 65 percent perform welding. More detailed analyses are available in the docket, including estimated percentages of the number of facilities in each category performing each operation.

Another metal fabrication and finishing operation that can emit MFHAP is plating. This operation was noted to be performed by some of the
[[Page 18339]]
facilities in the nine metal fabrication and finishing source categories, but is not regulated by this proposed rule. Plating operations are not regulated by this proposed rule because they are regulated elsewhere, as follows: Chromium electroplating tanks are subject to the Chromium Electroplating NESHAP (40 CFR 63, subpart N), while other plating operations at area sources are subject to the Plating and Polishing Area Source Rule (40 CFR part 63, subpart WWWWWW) which will be promulgated by June 15, 2008.

1. Metal Fabrication and Finishing Operations

The nine Metal Fabrication and Finishing source categories produce a wide variety of products using five general production operations that can emit MFHAP: (1) Dry abrasive blasting; (2) dry grinding and dry polishing with machines; (3) machining; (4) spray painting and coating; and (5) welding. The following is a brief description of each of these five fabrication and finishing operations regulated by this proposed rule.

Dry Abrasive Blasting Operations. This metal fabrication and finishing operation (also referred to in the industry as sand blasting, shot blasting, and shot peening) is used to clean or prepare a surface by forcibly propelling abrasive material against it. Commonly used abrasives include silica sand, glass beads, aluminum oxide, slag, garnet, steel shot, walnut shells, as well as other materials. Common applications of dry abrasive blasting include surface preparation for painting or coating; burr removal after machining, grinding, or welding; matte surface finishing; removal of flash from molded objects.

Two primary aspects differentiate the various types of abrasive blasting: The method of abrasive propulsion and the type of abrasive used. There are three primary methods of propelling the abrasive: Air pressure, using compressed air to propel the abrasive; water pressure, using air or water pressure to propel a wet abrasive slurry; or centrifugal wheels, which use a rotating impeller to mechanically propel the abrasive.

Abrasive blasting covers numerous applications under widely varying conditions. Blasting is also performed outdoors with a portable apparatus or indoors within specially constructed cabinets or enclosures/chambers, either manually, or as part of an automated process line. Because the applications of abrasive blasting are widely varied, there is a similarly wide variety of abrasive blasting equipment available.

Dry abrasive blasting equipment consists of the following general types of systems, listed from small to large: Portable blasters, blast cabinets or ``glove boxes'', blast chambers which can be 3 or 4sided structures, and ``bulk'' blasters that are totally enclosed and vented to a filtration device to collect and recycle the blast material. Shot peening is a common type of dry abrasive blasting that is a surface treatment used to increase the fatigue life of metal parts. In shot peening, a higher pressure is used to focus the abrasive on a localized area as opposed to general abrasive blasting that may be directed over a larger surface area. Shot peening generally refers to abrasive blasting with metallic or steel pellets, like BB shot. Shot peening is almost always performed in a contained area so that the pellets can be recovered and reused. Similarly, blasting performed with sand other media is also often performed in a contained area so that the media can be recovered and reused.

Dry Grinding and Dry Polishing Operations. These metal fabrication and finishing operations are very similar and vary only as to their timing in the fabrication and extent of abrasion. Not all parts are polished but most are ground. Grinding is performed on a work piece prior to fabrication or finishing operations to remove undesirable material from the surface or to remove burrs or sharp edges. Grinding is done using belts, disks, or wheels consisting of or covered with various abrasives, e.g., silica, alumina, silicon carbide, garnet, alundum, or emery. Grinding may be performed dry or may use lubricants or coolants such as water or waterbased mixtures, solutions, or emulsions containing cutting oils, soaps, detergents, wetting agents, or proprietary compounds. Polishing generally follows grinding. The purpose of the polishing operation is to remove any remaining metal and to prepare the surface for more refined finishing procedures. Burrs on castings or stampings may also be removed by polishing. Polishing is performed using hardfaced wheels constructed of muslin, canvas, felt or leather. Abrasives are applied to the wheels with synthetic adhesives or cements, typically silicatebase cements. The types of abrasives that are used in polishing include both natural and artificial abrasives. Lubricants including oil, grease, tallow, and special bar lubricants are used to prevent gouging and tearing when a fine polished surface is required and also to minimize frictional heat. Polishing may also be performed by hand without machines; however, no emissions occur from hand polishing.

Machining Operations. This metal fabrication and finishing operation includes activities such as turning, milling, drilling, boring, tapping, planing, broaching, sawing, cutting, shaving, shearing, threading, reaming, shaping, slotting, hobbing, and chamfering, where stock is removed from a work piece as chips by a machine that forces a cutting piece against a work piece. Shearing operations cut materials into a desired shape and size, while forming operations bend or conform materials into specific shapes. Cutting and shearing operations include punching, piercing, blanking, cutoff, parting, shearing and trimming. Forming operations include bending, forming, extruding, drawing, rolling, spinning, coining, and forging the metal. Machining is usually totally enclosed, where the enclosure is part of the operating equipment. Many of these machining operations use lubricants or liquid coolants either alone or in conjunction with enclosures.

Painting Operations. Paints and coatings (hereafter called ``paints'') are applied to metal fabrication and finishing products for surface protection, aesthetics, or both. Painting or coating (hereafter called ``painting'') is usually performed using a spray gun in a spray booth or with portable spray equipment. Paints may also be applied via dip tanks. The coated parts then pass through an open (flashoff) area where additional volatiles evaporate from the paint. The coated parts may pass through a drying/curing oven, or are allowed to air dry, where the remaining volatiles are evaporated.

Sprayapplied painting operations include any handheld device that creates an atomized mist of paint and deposits the paint on a substrate. For the purposes of this rule, spraypainting does not include thermal spray operations, also known as metallizing, flame spray, plasma arc spray, and electric arc spray, among other names, in which solid metallic or nonmetallic material is heated to a molten or semimolten state and propelled to the work piece or substrate by compressed air or other gas, where a bond is produced upon impact. Thermal spraying operations at area sources are subject to the Plating and Polishing Area Source NESHAP, subpart WWWWWW of this part.

Spray gun cleaning may be done by hand cleaning parts of the disassembled gun in a container of solvent, by flushing solvent through the gun without atomizing the solvent and paint residue, or by using a fully enclosed
[[Page 18340]]
spray gun washer. A combination of nonatomizing methods may also be used. A gun washer consists of a solvent reservoir and a covered enclosure that dispenses solvent for gun cleaning. The enclosure may also hold the gun for automated gun cleaning. During gun cleaning in a gun washer, the cleaning solvent is dispensed from the reservoir and sprayed through the gun while it is open.

Welding Operations. This metal fabrication and finishing operation joins two metal parts by melting the parts at the joint and filling the space with molten metal. The most frequently used method for generating heat is obtained either from an electric arc or a gasoxygen flame. The type of welding most commonly used in the metal fabrication and finishing source categories is thought to be electric arc welding.

Electric arc welding includes many different variations that involve various types of electrodes, fluxes, shielding gases, and types of equipment. Electric arc welding can be divided into that which uses consumable electrodes vs. nonconsumable electrodes. In electric arc welding, a flow of electricity across the gap from the tip of the welding electrode to the base metal creates the heat needed for melting and joining the metal parts. The electric current melts both the electrode and the base metal at the joint to form a molten pool, which solidifies upon cooling. Consumable welding rods are used when extra metal is needed as a filler for the joint to make a complete bond. The consumable rods must be close in composition to the base metals, and can vary with each application. An externally supplied gas (argon, helium, or carbon dioxide) can be used to shield the arc.

2. Metal Fabrication and Finishing HAP Emission Sources

All five of the metal fabrication and finishing operations described above can emit MFHAP. The MFHAP that can be emitted from the metal fabrication and finishing operations are in the form of particulate matter (PM) produced from the material being fabricated, PM emitted from the use of consumable welding rods, and MFHAP used to color paints (as pigments). In addition, there are VOHAP emitted from painting operations, where the VOHAP are used as vehicles and solvents for the paints. Details on the HAP emissions from each of the five potential HAPemitting operations follow below.

Dry Abrasive Blasting Emissions. The emissions from dry abrasive blasting are predominantly inert PM resulting from breakdown of the blast material which is composed of silica sand, glass beads, aluminum oxide, slag, garnet, steel shot, walnut shells, and other materials. Few if any blast materials contain MFHAP, therefore any MFHAP that is emitted from blasting would originate from the part or product being blasted. Occasionally the blasted part or product may be painted, in which case the PM will contain additional MFHAP if present in the pigments in the paint. Painted substrates are uncommon in the metal fabrication and finishing industries, since these industries primarily produce new products rather than recondition old ones. The blasted substrates typically include metals such as: Cadmium, chromium (primarily in stainless steel), iron, lead, magnesium, manganese (in both mild and stainless steels), mercury, molybdenum, nickel (in stainless steel), selenium, tin, vanadium, and zinc (in galvanized steel). All five MFHAP are potential components of blasting substrates.

Dry Grinding and Dry Polishing Emissions. Some metal fabrication and finishing machine operations, such as grinding and polishing, are often times dry operations which can emit PM that can contain MFHAP. Polishing by hand without the use of machines usually emits little or no PM or MFHAP due to the low level of abrasion that potentially can be induced by the worker's hands. All the PM or MFHAP in grinding and polishing is produced from the work piece itself. Thus, the composition of the PM and presence of MFHAP is dependent upon the metal being worked. As above for blasting, the metal fabrication and finishing substrates typically include metals such as: Cadmium, chromium (primarily in stainless steel), iron, lead, magnesium, manganese (in both mild and stainless steels), mercury, molybdenum, nickel (in stainless steel), selenium, tin, vanadium, and zinc (in galvanized steel). All five MFHAP are potential components of metal fabrication and finishing substrates and therefore, are also potential emissions from operations of dry grinding and dry polishing with machines.

Machining Emissions. Most of the machining operations in the metal fabrication and finishing industry are totally enclosed, where the enclosure is part of the equipment. Many of these operations use lubricants or liquid coolants, either alone or in conjunction with enclosures. Because any emissions generated by these machining operations, which would be in the form of PM, are captured or entrained in the liquid, little or no emissions are generated. Any MFHAP that is released from machining would originate from the part or product being machined.

Spray Painting Emissions. The sources of HAP emissions from spray painting operations are the metal pigments and solvents that are in the paints. A substantial fraction of paint that is atomized does not reach the part and becomes what is termed ``overspray'' and generates HAP emissions.

All five MFHAP are potential components of paint pigments that are used to provide color to the paint. The MFHAP are emitted when the paints are atomized during spray application. The proposed spray painting requirements of this proposed rule would only apply to those spray painting operations that sprayapply paints that contain MFHAP. Paints are considered to contain MFHAP if they contain any individual MFHAP at a concentration greater than 0.1 percent by mass. For the purpose of determining whether paints contain MFHAP, facilities would be able to use formulation data provided by the manufacturer or supplier, such as the material safety data sheet, as long as it represents each MFHAP compound in the paint that is present at 0.1 percent by mass or more for Occupational Safety and Health Administration (OSHA)defined carcinogens and at 1.0 percent by mass or more for other MFHAP compounds.

Paint solvents are used as vehicles for the paint pigments. These solvents include VOHAP such as xylenes, toluene, phenol, cresols/ cresylic acid, glycol ethers (including ethylene glycol monobutyl ether), styrene, methyl isobutyl ketone, and ethyl benzene. Paints used in spray painting are thinned with solvents so that the paints are fluid enough to be able to be delivered onto the parts and products via narrow spray gun nozzles. The solvents are considered to be completely volatilized during spray application of the paint and during curing or drying. Most solvents contain HAP. The solvents may also consist of volatile organic compound (VOC) emissions which contribute to ozone formation, an EPAregulated criteria pollutant.

The remaining HAP emissions are primarily from cleaning operations, such as cleaning of spray guns. The HAP emissions from both the cleaning solvent and the paint removed from the gun can be emitted during cleaning. Solvents used for equipment cleaning may contain the same HAP as the paints they remove. The HAP Emissions from gun cleaning are minimized when cleaning is performed in a manner such that an atomized mist or spray of gun cleaning solvent and paint residue is not created outside of a container that collects used gun cleaning solvent. [[Page 18341]]

Mixing and storage are other sources of HAP emissions. The HAP emissions can occur from displacement of HAPladen air in containers used to store HAP solvents or to mix paints containing HAP solvents. The displacement of vaporladen air also can be caused by changes in temperature or barometric pressure, or by agitation during mixing.

Welding Emissions. The type of welding most commonly used in the metal fabrication and finishing source categories is thought to be electric arc welding. This is also the type of welding that can produce the most MFHAP emissions, since a consumable electrode is used. Emissions from welding are in the form of a fume, which is defined to be particles that are small enough to be airborne for extended periods of time and are visible to the human eye. The size of particles in welding fume is highly variable with an average size around 1 micrometer ([mu]m), corresponding to what is commonly called the ``fume'' size range. Welding fumes have a bimodal distribution, with maximum concentrations in ``coarse'' (approximately 1.5 [mu]m) and ``fine'' (0.52 [mu]m) particle size ranges.

Welding fumes are a product of the base metal being welded, the consumable welding electrode or wire, the shielding gas, and any surface coatings or contaminants on the base metal. As much as 95 percent of the welding fume is thought to originate from the melting of the electrode or wire consumable. Welding fume constituents may include silica and fluorides, used to aid the welding operation, and HAP metals such as antimony, arsenic, beryllium, cobalt, mercury, and selenium, in addition to the five MFHAP: Cadmium, chromium, lead, manganese, and nickel. As noted above for dry abrasive blasting, chromium and nickel are found primarily in stainless steel, whereas manganese is found in both mild and stainless steels.

Among the electric arc welding operations that use a consumable electrode, shielded metal arc welding (SMAW) is used in more than 50 percent of welding. SMAW also was the first welding type to use a consumable electrode and suits most general purpose welding applications. SMAW, also called manual metal arc welding (MMAW) or ``stick'' possibly because it uses replaceable welding electrode rods that look like sticks, has a high fume formation rate as compared to other welding operations. The advantages of SMAW welding include its simplicity, low cost, portability, and the fact that a shielding gas is not needed. One restriction of SMAW is that since it uses metal rods that must be replaced, it is slower than the welding operations which use continuous electrodes.

Another type of welding that uses a consumable electrode and has a high fume formation rate is fluxedcore arc welding (FCAW). High fume formation occurs because the weld material is a liquid or ``flux'' and not a solid wire, and therefore is more volatile.

Gas metal arc welding (GMAW), originally called metal inert gas (MIG) welding because it used an inert gas for shielding, has a moderate fume formation rate as compared to other welding operations. The advantages of GMAW include its ability to be operated in semiautomatic or automatic modes. It is the only consumable welding type that can weld all commercially important metals, such as carbon steel, highstrength low alloy steel, stainless steel, nickel alloys, titanium, aluminum, and copper. With GMAW, a weld can be performed in all positions with the proper choice of electrode, shielding gas, and welding variables. Compared to SMAW, the rate of deposition of the electrode material and therefore welding rate is higher than with GMAW. The disadvantage is that the equipment for GMAW is more complex, more expensive, and less portable than SMAW.

Another type of welding that uses a consumable electrode and has a low fume formation rate is submerged arc welding (SAW). In this type of welding, the welding rod is not exposed to the atmosphere which lowers the potential for emissions.

Two welding operations that use nonconsumable electrodes are gas tungsten arc welding (GTAW) that is also called tungsten inert gas (TIG), and plasma arc welding (PAW). Because consumable electrodes are not used, this type of welding has low or no emissions.

The choice of welding method is determined by many variables that include but are not limited to substrate material and shape; type of weld needed; skill of welder; and amount of welding to be done, therefore, a change from one type of welding to another is not always possible.

The shape of the material is another variable that can affect fume formation rate. It also has been found that when the angle of welding is closer to 90[deg], lower fume formation occurs. If the shape of the part to be welded prevents repositioning the welding equipment, this pollution prevention technique also cannot be used.

In terms of welding rod feed rate, it has been found that the higher the wire feed rate the higher the fume formation rate. Also, a low fume welding rod that reduces fume by 30 percent as compared to other available products has been reported as recently available for use with FCAW. Minor effects to reduce fume formation rate have also been attributed to the speed that the welding torch moves along the weld, i.e., the ``travel speed.''

Carrier or shielding gas type and flow rate are also variables that have been found to affect welding fume formation rate. Substitution of argon gas reduces the fume formation rate. A reduction in fume of approximately 40 percent has been reported if argon is replaced as the shielding gas. The shield gas flowrate also can be optimized, with 35 cubic feet per hour the reported optimum rate. This rate is in the middle of the usual operating range and is thought to be low enough to minimize turbulence but high enough to protect the worker.

Voltage and current play a key role in the welding fume formation rate. While low voltage and/or current is known to lower the fume formation rate, the use of a pulsed current has been found to lower fume formation by up to 90 percent of the rate with straight current for some types of welding operations. The reduction in welding fume with a pulsed current is due to the change in metal electrode transfer mode from globular to spray, that results from moderately

FOR FURTHER INFORMATION CONTACT Dr. Donna Lee Jones, Sector Policies and Programs Division, Office of Air Quality Planning and Standards (D24302), Environmental Protection Agency, Research Triangle Park, North Carolina 27711, telephone number: (919) 5415251; fax number: (919) 5413207; email address: jones.donnalee@epa.gov.