NMFRC Fact Sheet: Proposed National Emission Standards for Hazardous Air Pollutants (NESHAP) for Plating and Polishing Operations

Introduction

On March 14, 2008, EPA published a proposed air pollution regulation that will affect many metal finishing operations. When finalized, the rule will apply to any facility with the potential to emit hazardous air pollutant (HAPs), notably cadmium, nickel, lead, manganese and chromium.   (The rule will not apply to chromium anodizing and plating, which are covered under a previous rule.)

The final Plating and Polishing NESHAP is expected to be published later in 2008 and shops will have two years from then to comply.  The full text of the regulation can be down loaded here.

In most cases, the proposed standard is more likely to involve changing management practices rather than purchasing new equipment, although some add-on devices may be needed for certain processes such as thermal metal sprays.

Which processes are affected?

The proposed regulation applies to any plating or polishing operation that uses or has emissions of cadmium, nickel, lead, manganese and chromium.  The most common processes in these categories include:

• cadmium electroplating,
• nickel electroplating,
• lead electroplating,
• tin/lead electroplating,
• electroless nickel plating,
• chromate conversion coating,
• nickel acetate sealing,
• sodium dichromate sealing,
• electroforming,
• manganese phosphating,
• electropolishing,
• mechanical polishing of metals, and
• thermal metal spraying.

Regulated sources do not include chromium electroplating and chromium anodizing processes, because those operations are already covered by NESHAP for Emissions from Hard and Decorative Chromium Electroplating and Chromium Anodizing Tanks (40 CFR part 63, subpart N).

What emissions control methods is EPA proposing?

Certain control emissions methods are required for all affected metal finishing processes performed in tanks.  Others pertain to specific types of plating or other finishing processes, such as metal sprays.

Facilities that would prefer to use equipment other than those listed in the regulation can seek approval to do so.  They will have to demonstrate that the alternative means of emission limitation achieves HAP emission reductions that are at least equivalent to the controls specified in this rule.

The various provisions of the regulation are summarized below.

1. Controls for All Affected Plating and Polishing Process Tanks

All new and existing affected plating and polishing processes performed in tanks, regardless of bath pH, presence of cyanide, or use of electricity, would be required to comply with the following management and pollution prevention practices:

• minimize bath agitation when removing tank objects;
• maximize dripping of bath solution back into tank by extending drip time when removing the tank objects and using drain boards (i.e., drip shields);
• optimize the design of barrels, racks, and parts to minimize dragout of bath solution,;
• use tank covers, if available on-site at the facility, whenever possible; and
• minimize or reduce heating during tank operation and when tanks are not in use.

2. Controls for Non-cyanide Electrolytic Process Tanks Operated at pH Less than 12.

The proposed rule requires owners or operators of non-cyanide electrolytic processes (e.g., nickel electroplating, electroforming, and electropolishing) operating at pH less than 12 to use a wetting agent/fume suppressant (WAFS) in the tank bath as directed by the manufacturer of plating chemicals. The proposed rule also require shops with affected non-cyanide electrolytic process tanks to implement the management and pollution prevention practices described previously in item 1 (Controls for All Affected Tanks).

To meet the requirement for WAFS, the shop would operate either a tank with bath chemistry that includes a WAFS or add WAFS separately to the bath.

As a compliance option EPA proposes that, in lieu of using WAFS, facilities may use control systems that include capture devices designed to capture the plating and polishing metal HAP emissions from the tanks, and to transport these metal HAP emissions to composite mesh pad (CMP), packed bed scrubber (PBS), or mesh pad mist eliminator (MPME) control devices.

3. Non-Electrolytic Process Tanks

The proposed rule would require new and existing facilities with affected non-electrolytic process tanks (e.g., electroless nickel, chromate conversion coating, manganese phosphating; and nickel acetate, dichromate, and lead sealing processes) to implement the management and pollution prevention practices described previously in item 1 (Controls for All Affected Tanks).

4. Controls for Electroplating and Electroforming Process Tanks with Cyanide Operated at a pH Equal to or Greater than 12

The proposed rule would require owners or operators of new and existing affected electroplating and electroforming process tanks with cyanide operating at pH equal to or greater than 12 to implement the management and pollution prevention practices described previously in item 1 (Controls for All Affected Tanks).

5. Controls for Flash or Short-term Electroplating Process Tanks

Under this proposed rule, ‘‘flash’’ or short-term electroplating processes are defined to be tanks that perform plating no more than 1 hour per day or 3 minutes per hour of plating time; or use covers for 95 percent of the total plating time.  An example might be a nickel strike bath. These tanks would be required to meet the management and pollution prevention practices, described previously in item 1 (Controls for All Affected Tanks).

6. Controls for Thermal Spraying Processes

For the proposed rule, existing thermal spraying processes are required to be equipped with control systems that are designed to provide capture of the metal HAP emissions from thermal spraying processes and transport these metal HAP emissions to water curtains, fabric filters, or HEPA filters. The control systems include capture devices such as hoods, enclosures, or any other duct intake devices with ductwork, dampers, manifolds, plenums, or fans. The use of such capture devices in combination with water curtains, fabric filters, or HEPA filters, if operated according to the manufacturers specifications, have been demonstrated to achieve at least 90% overall control.  In general, these types of capture and control systems are already in use for most thermal spraying operations.

The proposed rule would require that new thermal spraying operations include control systems that are designed to provide capture and control of the metal HAP emissions from these sources, and that transport these emissions from the affected source to fabric or HEPA filters. The use of such capture devices in combination with fabric or HEPA filters, if operated according to the manufacturers specifications, have been demonstrated to achieve 95% overall control.

7. Controls for Dry Mechanical Polishing Operations

New and existing dry mechanical polishing operations covered under the proposed rule would require control systems that are designed to capture the plating and polishing metal HAP emissions from dry mechanical polishing operations, and that transport these metal HAP emissions to cartridge, fabric, or HEPA filters.

What are the initial compliance requirements?

To meet initial compliance requirements, the proposed rule does not require any testing or monitoring to demonstrate compliance.  Rather, shops must certify that they have implemented the specified management practices and/or controls systems as discussed above.

What are the continuous compliance requirements?

The proposed rule requires owners or operators of all affected plating and polishing process tanks to demonstrate continuous compliance by adhering to the management and pollution prevention practices specified in this proposed rule, and by maintaining the appropriate records to document their compliance.

What are the notification, recordkeeping, and reporting requirements?

The proposed rule specifies the following notification, recordkeeping and reporting requirements:  Facilities

• must submit an Initial Notification and a Notification of Compliance Status.
• must submit an annual compliance certification and, if there were any deviations during the year, a report that describes the deviations and the corrective action taken.
• must maintain all records that demonstrate initial and continuous compliance with this proposed rule, including records of all required notifications and reports, with supporting documentation; and records showing compliance with the management and pollution.  Examples include:
• amount and frequency of WAFS additions,
• daily plating time; the time the tank is operated with a cover in place, and
• maintenance of any required control systems.

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