40 CFR 63, Subpart XXXXXX, also known as 6X, regulates potential emissions of cadmium, chromium, lead, manganese, and nickel from dry abrasive blasting, dry machining, dry grinding, spray painting, and welding. The U.S. Environmental Protection Agency (U.S. EPA) has identified the following nine (9) source categories as applicable:
- Electrical and Electronic Equipment Finishing Operations
- Fabricated Metal Products, Not Elsewhere Classified (NEC)
- Fabricated Plate Work (boiler shops)
- Fabricated Structural Metal Manufacturing
- Heating Equipment, except electric
- Industrial Machinery and Equipment Finishing Operations
- Iron and Steel Forging
- Primary Metal Products Manufacturing
- Valves and Pipe Fittings, NEC
IDEM’s Compliance and Technical Assistance (CTAP) staff are available to provide confidential phone and on-site assistance assessing your facility’s compliance with environmental regulations including 6X. Additionally, the U.S. EPA maintains a Questions & Answers [PDF] document (Revised on June 22, 2020), that provides guidance for the Nine Metal Fabrication and Finishing Source Categories and other interested stakeholders.
Am I subject?
A determination of applicability can be made by evaluating processes being operated and how those processes are classified.
Subpart 6X applies if an operation(s) that is associated with one (1) or more of the regulated (as listed in the NESHAP) NAICS (North American Industrial Classification System) codes represents at least 50% of total production. An operation(s) can be measured by length, area, volume, or mass. Production records along with the associated NAICS code(s) should be retained, as burden of proof falls on the potentially regulated entity.
|Subpart XXXXXX: 9 Metal Fabrication Applicability|
|By U.S. EPA Source Category with NAICS Codes|
|U.S. EPA Source Category||NAICS Code||NAICS Description|
|1||Electrical and Electronic Equipment Finishing Ops||335312||Motor and Generator Manufacturing|
|335999||All Other Miscellaneous Electrical Equipment and Component Manufacturing|
|2||Fabricated Metal Products, not elsewhere classified (NEC)||332117||Powder Metallurgy Part Manufacturing|
|332999||All Other Miscellaneous Fabricated Metal Product Manufacturing|
|3||Fabricated Plate Work (Boiler Shops)||332313||Plate Work Manufacturing|
|332410||Power Boiler and Heat Exchanger Manufacturing|
|332420||Metal Tank (Heavy Gauge) Manufacturing|
|4||Fabricated Structural Metal Manufacturing||332312||Fabricated Structural Metal Manufacturing|
|5||Heating Equipment, except Electric||333414||Heating Equipment (except Warm Air Furnaces) Manufacturing|
|6||Industrial Machinery and Equipment: Finishing Ops||333120||Construction Machinery Manufacturing|
|333132||Oil and Gas Field Machinery and Equipment Manufacturing|
|333911||Pump and Pumping Equipment Manufacturing|
|7||Iron and Steel Forging||332111||Iron and Steel Forging|
|8||Primary Metals Products Manufacturing||332618||Other Fabricated Wire Product Manufacturing|
|9||Valves and Pipe Fittings, NEC||332919||Other Metal Valve and Pipe Fitting Manufacturing|
Subpart 6X regulates emissions of Cadmium, Chromium, Lead, Manganese, and Nickel from dry abrasive blasting, dry machining, dry grinding, spray painting, and welding processes which use or cause emissions of one of the five (5) metals. Please note, welding is commonly found at metal fabrication companies and the rod or wire being utilized usually contains Manganese.
If your company does employ one (1) or more of these processes, it is important to familiarize yourself with the definitions in and requirements of 6X. As an example, machining and grinding employing the use of fluids for lubricating or cooling are excluded from 6X, but dry abrasive blasting operations are subject to the provisions of the rule.
As an overview, the requirements for metal fabrication and finishing involve minimizing dust generated from abrasive blasting, grinding, and polishing; operating all equipment in accordance with the manufacturer’s instructions; proper cleaning and storage of spray guns and painter training; and using welding processes with reduced fume generating capabilities. Dry abrasive blasting and welding require monitoring for the detection of visible emissions (U.S. EPA Method 22) at the primary vent, stack or opening from the building or the property border if blasting is conducted outside.
If visible emissions from welding are detected more than once during any consecutive twelve month period, a visual determination of opacity (U.S. EPA Method 9 [PDF]) must be conducted at the primary vent, stack or opening from the building within 24 hours of the second detection. Making a visual determination of opacity requires semiannual training and certification.
The U.S. EPA Flow Charts [PDF] for determining requirements includes a graduated emissions monitoring plan. A quick breakdown of the rules and requirements can be found in the U.S. EPA Fact Sheets for Metal Fabrication and Finishing Categories.
If your company is potentially subject to this rule, upon startup an initial notification [DOC] should be submitted to the U.S. EPA Region 5, and within 120 days of startup a Notification of Compliance Status [DOC]. Courtesy copies should be provided to IDEM as well.
Mailing addresses are as follows:
U.S. EPA Region 5
Compliance Tracker AE-17J
77 West Jackson Blvd.
Chicago, IL 60604-3590
Indiana Department of Environmental Management
Office of Air Quality Compliance and Enforcement Branch
100 North Senate Avenue IGCN 1003
Indianapolis, IN 46204-2251
When must I comply with the Rule?
Compliance with this rule must be achieved within 120 days of startup of the dry abrasive blasting, dry grinding and dry polishing, dry machining, spray painting, and/or welding process(es). Please note, if your company is subject to 6X, but is not compliant with this provision, it must do so as soon as possible.
Dry abrasive blasting and welding require monitoring for the detection of visible emissions (U.S. EPA Method 22) at the primary vent, stack or opening from the building or the property border if blasting is conducted outside.
If visible emissions from welding are detected more than once during any consecutive twelve month period, a visual determination of opacity (U.S. EPA Method 9) must be conducted at the primary vent, stack or opening from the building within 24 hours of the second detection. Making a visual determination of opacity requires semiannual training and certification.
The U.S. EPA Flow Charts for determining requirements includes a graduated emissions monitoring plan.
- January 31 - Annual Certification and Compliance Report due
- Within 120 days of startup - Initial Notification [DOC]
- Within 120 days of startup - Notification of Compliance Status [DOC]
U.S. EPA Resources
- Rule and Implementation Information
- Owner/Operator Certification for Painter Training (Example)
- Visual Determination of Fugitive Emissions [DOC], U.S. EPA Method 22
- U.S. EPA Method 9 – Visual Opacity
- Visible Emissions Field Manual [PDF], U.S. EPA Methods 9 and 22
- Visible Emission Observation Form [PDF], U.S. EPA Method 9
- U.S. Nine (9) Metal Fabrication and Finishing Area Source Categories Questions and Answers [PDF] (June 22, 2020)
- University of Northern Iowa, Iowa Waste Reduction Center
- Ohio EPA 6X Summary
- Kansas Small Business Environmental Assistance Program Presentation
- Acronyms List
- Compliance and Technical Assistance Program (CTAP) System
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- Enforcement Database
- Impaired Waters (e303d)
- Online Air Permit Search
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