Navigating the EPA's NESHAP Rule 6X

Are you in compliance?

Practical Welding Today March/April 2012
March 5, 2012
By: Greg Schreier

The EPAís NESHAP Rule 6X went into effect on July 25, 2011. Find out if this regulation applies to you; what steps are required if it does; and what equipment is out there to help keep your employees safe and the EPA happy.

Navigating the EPA's NESHAP Rule 6X -

The Clean Air Act required the Environmental Protection Agency (EPA) to develop air emission standards for a list of 187 hazardous air pollutants (HAPs). The standards are enforced to reduce exposure to HAPs because the chemicals are known to cause cancer or other serious health effects, such as birth defects.

The EPA introduced its National Emission Standards for Hazardous Air Pollutants (NESHAP) in 2008. Within this standard are the HAPs that apply to the metal fabrication industries—known as metal fabricating and finishing hazardous air pollutants, or MFHAPs. These are defined as materials that contain 0.1 percent by weight of cadmium, chromium, lead, or nickel; or 1.0 percent by weight of manganese. Manganese is particularly concerning to the welding industry, as it is a universal component of welding wire.

Whom Does the Rule Affect?

How do you know if your facility is using these materials? As a starting point, consult the Material Safety Data Sheet (MSDS) for the base materials that you are using, such as welding rods and welding wire. A standard MSDS lists hazardous ingredients in Section 2. If, for example, the material is shown to contain more than 2.5 percent of manganese by weight, the material is subject to the NESHAP 6X rule (see Figure 1).

The rule applies to companies that are primarily engaged—defined as 50 percent or more of their total labor—in one or more of the following categories: electrical and electronic equipment finishing, fabricated metal products, fabricated plate work (boiler shops), fabricated structural metal manufacturing, heating equipment (except electric), industrial machinery and equipment finishing, iron and steel forging, primary metal products manufacturing, and valve and pipe fittings (see Figure 2).

Operations that are affected by the rule cover eight processes: dry abrasive blasting (three types), dry grinding, dry polishing with machines, dry machining, spray painting (two types), and last but not least, welding.

Exceptions include military installations; NASA facilities; national nuclear security facilities; military munitions facilities; research or laboratories as defined in the Clean Air Act; tool, quality control, and equipment repair facilities; and welding facilities using less than 2,000 lbs. of rod or wire that does not contain any identified HAPs (per the MSDS).

Your facility is likely to be impacted if it is in one of the industry categories listed previously; is primarily engaged in one of the processes identified previously; exhausts the air straight outdoors; and fails an EPA Method 22 fugitive emission test.

Method 22, which is conducted to provide a visual determination of fugitive emissions from material sources, is performed by an observer with two stopwatches. The observer stands at least 15 feet away from an exhaust stack, with a clear view of the exhaust with the sun at his back, and lines up a dark background. He starts the watch in his left hand and runs it continuously for 15 minutes. He starts the watch in his right hand when emissions are observed (opacity), and stops it when they are not. If the observer recognizes opacity—defined as the quality of a particle that makes it impervious to light—during 20 percent or more of the 15-minute test period, Rule 6X applies.

Taking Action

NESHAP Rule 6X went into effect July 25, 2011, and existing facilities that were not in compliance were expected to notify the EPA by that date. What this author’s field experience has shown, however, is that many companies remain unaware of the deadline and the rule itself, especially smaller facilities that do not have a dedicated extremely hazardous substances specialist on staff.

The new rule is highly applicable to welding shops, and everyone engaged in welding needs to be aware of the rule and what is now required of them. As noted, welding processes use manganese, a hazardous substance associated with birth defects. Some welding shops rely on standard HVAC filtration to clean the air, exhausting welding fumes out to the atmosphere, which is a potential violation of the new EPA requirement. Other facilities simply open the shop door when fumes build up inside, with the same result. Even a dedicated dust and fume collection system may be in violation if it exhausts air outside and is older and/or not properly designed to handle the current processes.

Navigating the EPA's NESHAP Rule 6X -

Figure 2: These SIC codes are affected by NESHAP Rule 6X.

What actions are necessary if Rule 6X applies and your company has failed the Method 22 test?

  • Notify the EPA.
  • The Tier 1 response suggests you change your process to eliminate the HAP. You might try experimenting with different materials or different settings to reduce emissions. Whatever changes you implement, you must operate equipment according to the manufacturer’s instructions.
  • Conduct another Method 22 emissions test.
  • If the second test fails, “Corrective action must take place immediately after the failed Method 22 test,” per the Federal Register, page 42985, Welding compliance, Tier 2.

Cartridge Dust and Fume Collection

One corrective strategy that offers multiple benefits is installing a dust and fume collector with high-efficiency cartridge filtration. Cartridge filtration systems are identified in the regulation as an acceptable method to eliminate visible emissions.

A well-designed cartridge system will filter welding fumes and other hazardous contaminants properly, and the filtered air can either be recirculated into the facility or exhausted outside. These systems use self-cleaning mechanisms that pulse dirt off the filters, allowing units to run for extended periods between filter changeouts.

If air is exhausted outdoors, the EPA Rule 6X procedures will apply as stated. Contact your EPA regional office to find out which agency enforces this rule for a specific location. Under Method 22, the EPA requires ongoing annual compliance that is specific to the operation and is based on the date that your facility originally declared compliance.

If your company opts to recirculate the filtered air instead of exhausting it outside, the EPA NESHAP requirement no longer applies; however, the indoor air still must comply with OSHA permissible exposure limits (PELs). The collector may also be required to contain safety monitoring filters (also called afterfilters) for added filtration and backup protection. The lead photo shows a recirculating cartridge dust collection system.

Air recirculation is the single best way to maximize return on investment with a dust collector. By recirculating heated or cooled air back through the plant instead of venting it outdoors, you eliminate the cost to replace that conditioned air. Many facilities report five- to six-figure annual energy savings as well as additional savings from earned utility rebates and incentives.

Whether or not your company opts for a recirculating system, a high-efficiency dust and fume collector can greatly reduce or nearly eliminate employee exposure to welding chemicals. The result is a clean and energy-efficient work environment that promotes employee health, comfort, and morale; boosts productivity; and enhances manufacturing reliability.

When selecting a dust collection system, keep these tips in mind:

  • Source-capture systems that have flexible arms or hoods are popular for applications involving small parts and fixture welding. Ambient systems that filter all the air in the shop using a central collector or multiple smaller collectors sometimes better serve larger areas because they allow a facility to vary its operations and still capture all the fumes. Booths or custom enclosures form a middle ground between the two by isolating a specific area for fume collection.
  • Consider total cost of ownership (TCO)—also known as life-cycle cost. The equipment with the lowest initial cost may not be the best investment. A design that allows air recirculation and reduced maintenance can offer a payback in one to two years’ time.
  • Ask for a written guarantee of emissions. Sometimes equipment suppliers talk about removing 99.9 percent of contaminants of a certain particle size. The EPA and OSHA don’t regulate percentage efficiency claims, but they do want to know that emissions will be at or below required thresholds. Ask the filtration manufacturer for a written guarantee of emissions performance, stated as grains per cubic foot.
  • For best results, follow performance guidelines published by the American Conference of Governmental Industrial Hygienists (ACGIH).
  • Look for a local air filtration/dust collection supplier that is experienced in applying EPA NESHAP Rule 6X as well as appropriate OSHA and National Fire Protection Association (NFPA) standards for air quality and fire/explosion protection.


Federal Register, Environmental Protection Agency, 40 CFR Part 63

NESHAP, Nine Metal Fabrication and Finishing Area Source Categories, 40 CFR Part 63, subpart 6X, Questions and Answers

Minnesota Small Business Environmental Assistance Program (SBEAP)

U.S. EPA Office of Air Quality Planning and Standards

EPA Method 22—Visual Determination of Fugitive Emissions

Greg Schreier

Metalworking Market Manager
Camfil Farr Air Pollution Control (APC)
3505 S. Airport Road
Jonesboro, AR 72401
Phone: 800-479-6801

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