DATE: September 8, 2010 

SUBJECT: Section 112(d)(6) Technology Review for Steel Pickling NESHAP

Emission Standards Technical Support and Post Promulgation Activities

EPA Contract No. EP-D-06-118; EPA Work Assignment No. 4-6 

RTI Project No. 0210426.004.006 

FROM: Sandy Burns

TO: Phil Mulrine, EPA/OAQPS/SPPD/MMG

The purpose of this memorandum is to present the results of a review of available 

information on developments in practices, processes, and control technologies that apply to steel 

pickling, and specifically to sources subject to the national emission standards for hazardous air 

pollutants (NESHAP) for Steel Pickling - HCl Process Facilities and Hydrochloric Acid 

Regeneration Plants (40 CFR 63, subpart CCC). This analysis is part of the U.S. Environmental 

Protection Agency’s (EPA’s) review efforts in accordance with section 112(d)(6) of the Clean 

Air Act (CAA). Section I of this memorandum provides background information on the 

requirements of section 112(d)(6) of the CAA, the steel pickling source category, and the 

requirements of the Steel Pickling NESHAP. Section II discusses the review of information on 

developments in practices, processes, and control technologies that have occurred since the 

original development of this NESHAP. 

I. Background/Purpose

A. Requirements of Section 112(d)(6) of the CAA

Section 112 of the CAA requires EPA to establish technology-based standards for 

sources of hazardous air pollutants (HAP). These technology-based standards are often referred 

to as maximum achievable control technology, or MACT, standards. Section 112 also contains 

provisions requiring EPA to revisit these standards. Specifically, paragraph 112(d)(6) section 

states:

(6) REVIEW AND REVISION. – The Administrator shall review, and revise as 

necessary (taking into account developments in practices, processes, and control 

technologies), emission standards promulgated under this section no less often 

than every 8 years.

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For the purpose of this technology review, a “development” was considered to be any of 

the following: 

• Any add-on control technology or other that was not identified and considered during 

MACT development for the source category; 

• Any improvements in add-on control technology or other equipment (that was 

identified and considered during MACT development for the source category) that 

could result in significant additional emission reduction; 

• Any work practice or operational procedure that was not identified and considered 

during MACT development for the source category, and Any process change or 

pollution prevention alternative that could be broadly applied that was not identified 

and considered during MACT development for the source category. 

B. Description of Source Category and NESHAP Requirements

Steel pickling is the process in which the heavy oxide crust or mill scale that develops on 

the surface of steel during hot forming or heat treating is removed chemically in a bath of 

aqueous acid solution. Removal of the oxide layer is necessary to prepare the surface for 

subsequent shaping or finishing. The source category does not include facilities which pickle 

steel using acids other than hydrochloric acid (HCl). The category includes both continuous and 

batch pickling operations. In the continuous pickling process the steel is fed through a sequence 

of tanks in a countercurrent direction to the flow of the acid solution; next, the steel is passed 

through a series of rinse tanks or a rinsing section. In the batch pickling process, the steel is 

immersed in an acid solution until the scale or oxide film is removed, lifted from the bath, 

allowed to drain, and then rinsed by spraying or immersion in rinse tanks. 

Hydrochloric acid used in the pickling bath can be recovered as regenerated acid, 

typically 16 to 20 percent HCl, from the spent pickle liquor. A marketable iron oxide product is 

also produced as a byproduct of the spray roasting or fluidized bed roasting processes used in the 

acid plants. Waste liquor conversion and acid recovery are complete in both of these processes. 

Alternatively, if waste liquor meets certain criteria it can be used by wastewater treatment plants 

for phosphorus removal. 

Pickling lines of all types employ processing tanks that contain HCl solution. Emissions 

of HCl in the forms of HCl gas and mist of HCl in water are formed at the surface of the acid 

bath. Acid regeneration plants produce emissions containing HCl that is not recovered as acid 

solution and also chlorine (Cl2), which is formed as an unwanted byproduct of the process. 

Wet scrubbers are the principal technology used to control emissions from steel pickling 

and acid regeneration. 

 

The Steel Pickling NESHAP, which was promulgated on June 22, 1999 (40 FR Part 63, 

Subpart CCC) regulates HCl and Cl2 emissions from new and existing HCl process steel pickling 

lines and HCl regeneration plants. To comply with the NESHAP facilities must comply with 

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emission limits for HCl and Cl2. In order to meet these emission limits, facilities employ 

scrubbers (either a packed tower scrubber, sieve tray scrubber, or horizontal packed bed 

scrubber), although a particular control device is not specified in the rule. The NESHAP also 

specifies work practice standards, initial performance testing, ongoing compliance monitoring, 

recordkeeping, and reporting requirements. 

II. Search for Other Applicable Technology Developments for Steel Pickling

 Searches of the RACT/BACT/LAER Clearinghouse and the Internet were conducted to 

identify other technologies or developments that could be applied to the Steel Pickling source 

category. The results of these searches are described in the following paragraphs. 

RACT/BACT/LAER Clearinghouse

 

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 Under EPA’s New Source Review (NSR) program, if a company is planning to build a 

new plant or modify an existing plant such that air pollution emissions will increase by a large 

amount, the company must obtain an NSR permit. The NSR permit is a construction permit 

which requires the company to minimize air pollution emissions by changing the process to 

prevent air pollution and/or installing air pollution control equipment. 

The terms “RACT,” “BACT,” and “LAER” are acronyms for different program 

requirements under the NSR program. RACT, or Reasonably Available Control Technology, is 

required on sources in areas that are not meeting national ambient air quality standards (i.e., nonattainment areas). BACT, or Best Available Control Technology, is required on major new or 

modified sources in attainment areas. LAER, or Lowest Achievable Emission Rate, is required 

on major new or modified sources in non-attainment areas. 

 BACT and LAER (and sometimes RACT) are determined on a case-by-case basis, 

usually by State or local permitting agencies. EPA established the RACT/BACT/LAER 

Clearinghouse, or RBLC, to provide a central database of air pollution technology information 

(including past BACT and LAER decisions contained in NSR permits) to promote the sharing of 

information among permitting agencies and to aid in future case-by-case determinations. 

However, data in the RBLC are not limited to sources subject to RACT, BACT, and LAER 

requirements. Noteworthy prevention and control technology decisions and information are 

included even if they are not related to past RACT, BACT, or LAER decisions. 

 The RBLC contains over 5,000 air pollution control permit determinations that can help 

identify appropriate technologies to mitigate most air pollutant emission streams. It was 

designed to help permit applicants and reviewers make pollution prevention and control 

technology decisions for stationary air pollution sources, and includes data submitted by several 

U.S. territories and all 50 States on over 200 different air pollutants and 1,000 industrial 

processes.

The RBLC was searched for facilities that conduct steel pickling or hydrochloric acid

regeneration. Twelve steel pickling facilities and four acid regeneration plants were identified, 

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all of which use a scrubber for control of HCl emissions. No new control technologies or 

developments in existing control technologies were identified to further reduce emissions from 

steel pickling or acid regeneration plants. 

Internet Search

A general search of the Internet was conducted for information on new processes and 

control technologies for steel pickling and HCl acid regeneration. The search identified two 

technologies which could potentially be used in lieu of steel pickling in certain instances, without 

HCl emissions. The first, Smooth Clean Surface (SCS) uses patented roller brushes to remove 

scale from steel sheets and coils. However, this technology leaves the last layer of scale resulting 

in a product that is rust-resistant, but is not conducive to in-line galvanizing, painting, enameling 

or electrolytic plating; some types of forming, including hydroforming, cold reduction and deep 

draw also cannot be used with SCS treated steel.3,4 It is therefore not a viable replacement for 

steel pickling operations. The second technology, Eco Pickled Surface (EPS), could potentially 

become a low-emission alternative for steel pickling. EPS blasts steel with an acid-free slurry 

which, like steel pickling, removes all layers of scale. However, since EPS only became 

commercially available in 2009, it is not yet a proven technology and cannot be considered as a 

replacement for current steel pickling operations.5

III. References

1. National Emission Standards for Hazardous Air Pollutants for Steel Pickling - HCl Process 

Facilities and Hydrochloric Acid Regeneration Plants – Background Information for 

Promulgated Standards (EPA 453/R-98 010b). Office of Air Quality Planning and 

Standards. U.S. Environmental Protection Agency, Research Triangle Park, NC. December 

1998. 

2. EPA, Technology Transfer Network, Clean Air Technology Center - RACT/BACT/LAER 

Clearinghouse. http://cfpub.epa.gov/rblc/index.cfm?action=Search.BasicSearch&lang=en 

3. SCS, Smooth Clean Surface technology. http://www.scsprocess.com/. Accessed June, 2010. 

4. Telecon, S. Burns, RTI International to J. Grossheim, Fulton County Processing. June 2010. 

5. Eco-Pickled Surface technology. http://www.epsprocess.com/. Accessed June, 2010. 

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