PROPOSED AMENDMENTS TO THE HEXAVALENT CHROMIUM 

AIRBORNE TOXIC CONTROL MEASURE FOR CHROME PLATING AND 

CHROMIC ACID ANODIZING OPERATIONS 

Stationary Source Division 

Air Quality Measures Branch 

Release Date: August 11, 2006 

To Be Considered by the Board: September 28, 2006 
State of California 

AIR RESOURCES BOARD 

STAFF REPORT: INITIAL STATEMENT OF REASONS 

FOR PROPOSED RULEMAKING 

Public Hearing to Consider 

ADOPTION OF THE PROPOSED AMENDMENTS TO THE HEXAVALENT 

CHROMIUM AIRBORNE TOXIC CONTROL MEASURE FOR CHROME 

PLATING AND CHROMIC ACID ANODIZING OPERATIONS 

To be considered by the Air Resources Board on September 28, 2006, at: 

California Environmental Protection Agency 

Headquarters Building 

1001 “I” Street 

Sacramento, California 

Stationary Source Division: 

Robert Fletcher, P.E., Chief 

Robert D. Barham, Ph.D., Assistant Division Chief 

Janette Brooks, Chief, Air Quality Measures Branch 

Carla D. Takemoto, Manager, Technical Evaluation Section 

This report has been prepared by the staff of the Air Resources Board. Publication does not 

signify that the contents reflect the views and policies of the Air Resources Board, nor does 

mention of trade names or commercial products constitute endorsement or recommendation for 

use. 
Acknowledgements

Contributing Authors

Shobna Sahni, M.P.H. (Lead) 

Carla Takemoto 

Reza Mahdavi, Ph.D. 

Tony Servin, P.E. 

Robert Barrera 

Legal Counsel

Robert Jenne, Esq., Office of Legal Affairs 

_______________________________________________________________________ 

We are particularly grateful to Mr. Jose Mauro Saldana for his untiring assistance in the 

preparation of this report. 

We also wish to acknowledge the participation and assistance of: 

Metal Finishing Association of Southern California 

Surface Technology Association 

We would also like to acknowledge the participation and assistance of air pollution control 

and air quality management districts. In particular, we would like to thank the individuals 

at the following districts that participated in the ARB/District Working Group: 

Richard Wales, Antelope Valley Air Quality Management District 

Randy Frazier, Bay Area Air Quality Management District 

Karla Sanders, Feather River Air Quality Management District 

Jose De Guzman and Mark Loutzenhiser, 

Sacramento Metropolitan Air Quality Management District 

Archie de la Cruz, Cara Bandera, Dave Byrnes, 

San Diego County Air Pollution Control District 

Chay Thao, Martin Keast, John Copp, 

San Joaquin Valley Air Pollution Control District 

Shasta County Air Quality Management District 

Robert Gottschalk, Andrew Lee, Jay Chen, Susan Nakamura, Marco Polo, 

Thomas Liebel, Joan Niertit, Jill Whynot, Mike Garibay, David Jones, and 

Sam Vergara, South Coast Air Quality Management District 

Terri Thomas, Ventura County Air Pollution Control District
For the emissions testing program we want to acknowledge the invaluable 

assistance of: Mr. Dominic Nole, Mr. Dan Cunningham, Mr. Dean High, 

Mr. Paramo Hernandez, Mr. Ray Lucas, Mr. Chad Medico, Mr. John Martin, and 

Mr. Ralph Hersher

We also acknowledge the assistance of the tested facilities: Sigma Plating, 

Excello Plating, Van Nuys Plating, Alta Plating, Sherm’s Custom Chrome, Clovis 

Specialty Plating, Walker Custom Chrome 

Numerous ARB staff helped in the emissions testing program and in development 

of this report. In particular we acknowledge: Alex Barber; Ron Barros; 

Nicholas Berger; Darryl Burns; Chris Clark; Monique Davis; Steve Eve; Cynthia Garcia; 

Marline Hicks; Chris Nguyen; Olufemi Olaluwoye; Johnnie Raymond; Don Ridgley; 

Betsy Ronsse; Peter Samra; Dale Shimp; David Todd, Source Testing Lead; Roxana 

Walker; Evan Wong; Glen Villa; Zuzana Vona 
i 

Table of Contents

Executive Summary ES-1 

I. Introduction ................................................................................................................1 

A. Overview ....................................................................................................................1 

B. Goals of the Proposed Amendments .........................................................................2 

C. Regulatory Authority...................................................................................................3 

D. Existing State Control Measure..................................................................................5 

E. Federal Regulations ...................................................................................................6 

F. Current Air District Rules............................................................................................7 

G. Barrio Logan, A Case Study of Near Source Impacts ................................................9 

H. Hexavalent Chromium Emissions Study and Conclusions.......................................10

II. Need for Further Regulation.....................................................................................13 

A. Characteristics, Sources, and Ambient Concentrations of Hexavalent 

 Chromium and Chromium Compounds....................................................................14 

B. Health Impacts .........................................................................................................18 

C. Barrio Logan: A Case Study of Near Source Impacts .............................................19 

D. Proximity of Facilities to Sensitive Receptors...........................................................20

III. Public Outreach and Data Collection .......................................................................24 

A. Public Involvement ...................................................................................................24 

B. Data Collection Tools ...............................................................................................25

IV. Chromium Plating and Chromic Acid Anodizing Operations ....................................28 

A. Overview ..................................................................................................................28 

B. Types of Chromium Operations ...............................................................................29 

C. Data Resources .......................................................................................................30 

D. Industry Characterization .........................................................................................31
ii 

V. Emissions.................................................................................................................39 

A. Overview ..................................................................................................................39 

B. Emission Factor Background ...................................................................................39 

C. Emissions Testing Program .....................................................................................40 

D. Statewide Hexavalent Chromium Emissions............................................................47 

E. Fugitive Emissions ...................................................................................................49

VI. Reducing Hexavalent Chromium Emissions ............................................................52 

A. In-tank Controls........................................................................................................52 

B. Add-on Air Pollution Control Devices .......................................................................58 

C. Alternative Processes...............................................................................................59

VII. Health Risk Assessment ..........................................................................................66 

A. Overview ..................................................................................................................66 

B. Health Risk Assessment Process ............................................................................66 

C. Factors that Affect Health Risk Assessments...........................................................73 

D. Cancer Risk Assessment .........................................................................................74 

E. Non-Cancer Risk Assessment .................................................................................75

VIII. Proposed Risk Reduction Approach and Benefits....................................................78 

A. Best Available Control Technology ..........................................................................78 

B. Emissions and Cancer Risk Reduction Benefits ......................................................80 

C. Other Aspects of the Staff’s Proposal ......................................................................82

IX. Proposed Amendments and Alternatives .................................................................84 

A. Summary of the Existing Airborne Toxic Control Measure.......................................84 

B. Summary of the Proposed Amendments..................................................................84 

C. Basis for the Proposed Amendments.......................................................................97 

D. Alternatives to the Proposed Amendments ..............................................................97 

E. Recommendation ...................................................................................................101
iii 

X. Economic Impacts..................................................................................................103 

A. Summary of the Economic Impacts........................................................................103 

B. Economic Impact Analysis .....................................................................................104

XI. Environmental Impacts...........................................................................................118 

A. Legal Requirements ...............................................................................................118 

B. Analysis of Reasonably Foreseeable Environmental Impacts................................119 

C. Reasonably Foreseeable Mitigation Measures ......................................................122 

D. Reasonably Foreseeable Alternative Means of Compliance..................................123 

E. Community Health and Environmental Justice.......................................................123 
iv 

List of Tables

Table ES-1. Sixty-three Facilities have Estimated Cancer Risk of Over 

10 per Million Exposed People (2005 Baseline) ..............................................8

Table ES-2. Proposed Hexavalent Chromium Emission Limits for Existing 

 Facilities ........................................................................................................11

Table ES-3. Adoption of Staff’s Proposal Significantly Reduces the Estimated 

 Cancer Risk from Hexavalent Chromium Emissions .....................................13

Table ES-4. Adoption of Staff’s Proposal Offers the Greatest Reduction in 

 Significant Community Cancer Risk ..............................................................18

Table I-1. Air Districts with Active Chromium Plating and/or Anodizing 

Facilities and Corresponding Prohibitive Rule .................................................8

Table II-1. Hexavalent Chromium Mean Concentration in Air Districts with 

Chromium Plating and Anodizing Facilities for the Year 2005.......................16

Table IV-1. Description of Hexavalent Chromium Operations..........................................30

Table IV-2. Number of Operations by Plating Type..........................................................32

Table IV-3. Hexavalent Chromium Plating Type and Ampere-hours (2003) ....................33

Table IV-4. Number of Employees at Chromium Plating and Chromic Acid 

 Anodizing Facilities........................................................................................37

Table V-1. Decorative Chromium Plating Emission Factors in Existence Prior to ARB 

Testing Program (milligrams/ampere-hour) ...................................................40

Table V-2. Average Hexavalent Chromium Emission Rates and Selected Testing 

Parameters for Phase 1.................................................................................41

Table V-3. Average Hexavalent Chromium Emission Rates and Selected 

 Testing Parameters for Phase II....................................................................44

Table V-4. Chemical Fume Suppressants Approved for Use at Specified 

 Surface Tensions...........................................................................................45

Table V-5. Plating Bath Contaminants, Concentration Levels Where Bath 

Clean-up is Recommended, and Hexavalent Chromium Emission 

Rates.............................................................................................................47

Table V-6. Summary of Indoor Air Results During Emissions Testing Program..............50
v 

Table VI-1. Types of Chemical Fume Suppressants Used in California in 2003..............56

Table VI-2. Summary of Chemical Fume Suppressant Mechanism of Control 

and Recommended Surface Tension ............................................................57

Table VI-3. Cost Estimate for Conversion to Trivalent Chromium....................................61

Table VII-1. Inhalation Cancer Potency Factors for Common Carcinogens......................67

Table VII-2. Hexavalent Chromium Health Effects Values Used in Non-Cancer 

Health Risk Assessment................................................................................68

Table VII-3. Key Parameters for Air Dispersion Modeling and Health Risk 

Assessment...................................................................................................70

Table VII-4. Generic Facility Parameters for Air Dispersion Modeling and 

Health Risk Assessment................................................................................71

Table VII-5. Key Parameters for Assessing Estimated Cancer and Non-Cancer 

Health Impacts for Chromium Plating and Chromic Acid 

Anodizing Facilities........................................................................................73

Table VII-6. Sixty-three Facilities have Estimated Cancer Risk of Over 

 10 per Million Exposed People (2005 Baseline) ............................................75

Table VIII-1. Adoption of Staff’s Proposal Significantly Reduces the Estimated 

Cancer Risk from Hexavalent Chromium Emissions .....................................81

Table VIII-2. Adoption of Staff’s Proposal Significantly Reduces the Estimated 

Cancer Risk from Hexavalent Chromium Emissions for Off-Site Workers.....81

Table IX-1. Definitions Proposed for Modification ............................................................86

Table IX-2. New Definitions Proposed for Addition ..........................................................86

Table IX-3. Proposed Hexavalent Chromium Emission Limits for Existing Facilities .......89

Table IX-4. Chemical Fume Suppressants Approved for Use at Specified Surface 

 Tensions........................................................................................................94

Table IX-5. Adoption of Staff’s Proposal Offers the Greatest Reduction in Significant 

Community Cancer Risk..............................................................................100

Table X-1. Estimated Compliance Costs (Other than Those for Add-On Air 

Pollution Control Devices) ...........................................................................106

Table X-2. Costs for HEPA Add-on Air Pollution Control Devices.................................107

Table X-3. Number of Affected Hexavalent Chromium Plating and Chromic Acid 

Anodizing Facilities by Air District................................................................114
vi 

Table XI-1. Distribution of Chromium Plating and Chromic Acid Anodizing 

Facilities in the Los Angeles and Orange County Areas..............................124
vii 

List of Figures

Figure ES-1. Location and Type of Operation Performed at Chromium Plating 

and Chromic Acid Anodizing Facilities in California (2003) .............................5

Figure ES-2. Throughput (in Ampere-hours) for Chromium Plating and Chromic Acid 

Anodizing Facilities in California (2003)...........................................................6

Figure ES-3. Baseline Hexavalent Chromium Emissions are About 

 Four Pounds (2005).........................................................................................7

Figure ES-4. Forty-three Percent of Facilities are Located Near Sensitive Receptors .........9

Figure IV-1. Main Components of an Electroplating Tank.................................................29

Figure IV-2. Distribution of Chromium Operations by District (2003).................................31

Figure IV-3. Distribution of Hexavalent Chromium Operations by Type (2003).................32

Figure IV-4. Throughput (in Ampere-hours) for Chromium Plating and Chromic Acid 

Anodizing Facilities in California (2003).........................................................33

Figure IV-5. Distribution of Emission Controls by Type of Chromium Operation...............34

Figure IV-6. Distance (in Meters) Between Hexavalent Chromium Facilities and the 

Nearest Sensitive Receptor...........................................................................36

Figure IV-7. Gross Annual Revenue for Hexavalent Chromium Plating and Anodizing 

Facilities (2003) .............................................................................................37

Figure V-1. Temporary ‘Hood’ for Capturing Hexavalent Chromium Emissions at 

Decorative Chromium Plating Facilities.........................................................43

Figure V-2. Statewide Hexavalent Chromium Emissions in 2003 Were 14.4 Pounds......48

Figure VII-1. Percent Concentration of Hexavalent Chromium at Increasing 

Distances from the Source ............................................................................72

Figure VIII-1. Comparison of Cancer Risks (MICR) Remaining After Application 

of Controls at Various Throughputs...............................................................79
viii 

List of Appendices

Appendix A: Proposed Regulation Order for the Proposed Amendments 

to the Chromium Plating ATCM 

Appendix B: Chronology of Meetings 

Appendix C: Industry Survey Form 

Appendix D: Supplier Survey Form 

Appendix E: Economic Survey Forms 

Appendix F: Results of Emission Testing Program 

Appendix G: Results of SDCAPCD Dust Samples Collected from Hexavalent 

Chromium Plating Facilities 

Appendix H: Air Quality Modeling Parameters and Results 

Appendix I: Analysis of Proximity of Chromium Plating and Chromic Acid 

Anodizing Facilities in a Southern California Community 
ES-1 

Executive Summary 

The Air Resources Board (ARB) staff is proposing amendments to the Hexavalent 

Chromium Airborne Toxic Control Measure for Chrome Plating and Chromic Acid 

Anodizing Operations (Chromium Plating ATCM or ATCM). The amendments are 

proposed as a result of our evaluation of the 226 chromium plating and chromic acid 

anodizing facilities in California. 

In 1986, the Board identified hexavalent chromium as a toxic air contaminant (TAC). 

Hexavalent chromium was determined to be an extremely potent human carcinogen with 

no known safe level of exposure. Only dioxin is a more potent carcinogen than 

hexavalent chromium. Exposure over a lifetime to very low hexavalent chromium 

concentrations can substantially increase a person’s chance of developing cancer. 

Due to its potential cancer risk, ARB has adopted a number of control measures for 

hexavalent chromium sources, including chromium plating and chromic acid anodizing 

facilities. The current ATCM reduced emissions of hexavalent chromium by over 

90 percent, and in some cases by over 99 percent. Other air district programs have also 

reduced emissions of hexavalent chromium. As a result, ambient levels of hexavalent 

chromium are low and have been reduced by about 60 percent since the early 1990s. 

Based on community concerns and the potency of hexavalent chromium, the staff has 

re-evaluated the current Chromium Plating ATCM. We found that people living near 

many of these facilities are exposed to unacceptable concentrations of hexavalent 

chromium. Our evaluation showed that 43 percent of chromium plating and chromic acid 

anodizing operations are located within 100 meters of sensitive receptors and about 

30 percent of the facilities have emissions sufficient to produce a potential cancer risk of 

greater than ten per million exposed people. The data also show that the chromium 

plating facilities are often located in low income and ethnically diverse communities. 

In the evaluation, we also found that reliable add-on air pollution control devices, such as 

high efficiency particulate arrestor (HEPA) filters, are available. These controls now 

represent best available control technology (BACT) for intermediate and large sized 

facilities that can result in higher community risks. BACT for smaller facilities, those with 

emissions that can relatively easily be controlled to the levels needed to keep community 

risk low (under one per million), is use of specific chemical fume suppressants. In our 

proposal, all 226 facilities would be affected; 89 of those facilities would need to meet an 

emission limit equivalent to that achieved by HEPA filters and another 48 facilities would 

have to use specific chemical fume suppressants. The other facilities are in substantial 

compliance. The requirements would be phased-in over time, with facilities close to 

receptors having to install BACT in two years, versus five years for other facilities. 

By requiring BACT for all facilities, remaining cancer risks would be reduced by up to 

85 percent in communities close to facilities. We also estimate that adoption of the staff’s 

proposal will reduce the estimated cancer risk for about 75 percent of facilities to no more 

than one per million exposed persons, with 92 percent of facilities having estimated 

cancer risks of less than ten per million exposed persons. The proposal would also 
ES-2 

isolate new chromium plating or chromic acid anodizing facilities from people and require 

housekeeping measures to address fugitive emissions. 

Staff has determined that costs for some individual businesses are expected to be 

significant and may adversely impact their profitability. Some smaller volume plating or 

anodizing businesses may decide to cease chromium plating or anodizing operations 

rather than make the investments needed to comply. This analysis assumes that affected 

facilities would install HEPA filters, although there may be less costly equivalent options 

available, and the facilities cannot recover their costs through increased prices. 

This Executive Summary provides an overview of the staff’s proposal, including the basis 

and rationale, key provisions, and the environmental and economic impacts. The staff 

report, entitled “Proposed Amendments to the Hexavalent Chromium Airborne Toxic 

Control Measure For Chrome Plating and Chromic Acid Anodizing Operations,” presents 

detailed information related to the staff’s proposal, as well as the proposed regulation 

order. 

A. Background

1. What is chromium plating and chromic acid anodizing? 

Hexavalent chromium plating, or simply chromium plating, is the electrical application of a 

coating of chromium onto a surface for decoration, corrosion protection, or for durability. 

An electrical charge is applied to a tank (bath) containing an electrolytic salt (chromium 

anhydride) solution. The electrical charge causes the chromium metal particles in the 

bath to fall out of solution and deposit onto objects placed in the plating solution. The 

most familiar type of chromium plating is the decorative chromium plating process which 

provides a bright, shiny finish onto objects such as wheels and plumbing fixtures. During 

chromic acid anodizing, an oxidation layer is generated on the surface of the part. These 

electrolytic processes cause mists containing hexavalent chromium to be ejected from the 

plating tank which are eventually emitted into outdoor air. 

2. What is hexavalent chromium? 

Hexavalent chromium is the cation of a metal salt and does not occur naturally. 

Generally, hexavalent chromium ions are produced under strong oxidizing conditions from 

metallic chromium, with the most common ions being chromate ion (CrO4

-2) or dichromate 

ion (Cr2O7

-2). Unlike many pollutants which are gases, hexavalent chromium is a particle. 

3. How is hexavalent chromium emitted from the plating/anodizing process? 

In the chromium plating process, only about 20 percent of the electrical current applied 

actually deposits chromium onto the part. The remaining current forms bubbles, 

hydrogen gas at the cathode and oxygen at the anode, that rise to the surface of the bath. 

As these bubbles burst, hexavalent chromium is emitted into the air. 
ES-3 

4. Why are we concerned about emissions of hexavalent chromium? 

Hexavalent chromium is a known human carcinogen. Prolonged exposure causes lung 

cancer. The Board identified hexavalent chromium as a TAC in 1986. A cancer unit risk 

factor of 0.15 (μg/m3

)

-1 was developed in support of the TAC identification by the Office of 

Environmental Health Hazard Assessment (OEHHA) and approved by the Scientific 

Review Panel on TACs. This value means that a person’s chance of developing cancer 

due to exposure to 1 μg/m3

 of hexavalent chromium over a 70 year lifetime would be 

146,000 chances per million people, almost 15 percent. Only one other identified TAC, 

dioxin, has been determined more likely to cause cancer than hexavalent chromium. 

When the Board designated hexavalent chromium as a TAC, they further determined that 

there was no known level of exposure that would be considered safe. 

5. What does State law require ARB to do to reduce the public’s exposure to 

toxic air contaminants?

Health and Safety Code section 39666 requires ARB to adopt control measures to reduce 

emissions of TACs. When adopting or amending ATCMs for TACs, if no safe threshold 

exposure level is identified, the ATCM is to reduce emissions to the lowest level 

achievable through the application of BACT or a more effective control method, in 

consideration of health risk and cost. 

6. What does the current ATCM require? 

Originally adopted in 1988 and amended in 1998, the Chromium Plating ATCM set forth 

the requirements for reducing hexavalent chromium emissions based on the type of 

operation. Most hard chromium plating facilities were required to reduce hexavalent 

chromium emissions by 99 percent or more. This was achieved through installation of 

add-on air pollution control devices. Decorative chromium plating and chromic acid 

anodizing facilities were required to reduce uncontrolled emissions by at least 95 percent. 

However, they were not required to use add-on air pollution control devices. A brief 

summary of the requirements follows: 

• Hard chromium plating facilities are required to install add-on air pollution control 

devices to meet emission limits ranging from 0.15 milligrams/ampere-hour to 

0.006 milligrams/ampere-hour, depending on levels of throughput. An alternative 

surface tension limit was provided for hard chromium plating facilities with 

throughput levels of 500,000 ampere-hours or less; and 

• Decorative plating and chromic acid anodizing facilities must comply with either an 

emission limit using add-on air pollution control devices or meet a surface tension 

limit. Most facilities comply by using chemical fume suppressants to meet the 

surface tension limit. 

The ATCM was amended in 1998 to establish equivalency with the National Emission 

Standards for Chromium Emissions from Hard and Decorative Chromium Electroplating 

and Chromium Anodizing Tanks (Chromium Plating NESHAP) (U.S. EPA, 1995). 
ES-4 

Therefore, chromium plating and chromic acid anodizing facilities are only subject to 

California’s Chromium Plating ATCM. 

7. Why did ARB staff decide to evaluate the existing ATCM? 

Due to the carcinogenicity of hexavalent chromium, and in response to community 

concerns, ARB staff undertook an evaluation of the Chromium Plating ATCM. The staff 

evaluated if people located near chromium plating or chromic acid anodizing facilities 

were adequately protected from emissions of hexavalent chromium. Staff also evaluated 

if technologies were available to reduce hexavalent chromium emissions, if necessary. 

As part of the evaluation, staff determined that 43 percent of the operations are located 

within 100 meters of a sensitive receptor, such as a residence or school. By conducting 

an emissions testing program and air quality modeling, staff determined that these 

sensitive receptors may be exposed to unacceptable hexavalent chromium 

concentrations. ARB staff also found that reliable add-on air pollution control devices 

such as HEPA filters are now available and are used by many facilities to reduce 

hexavalent chromium emissions. 

Concurrent with the review of the Chromium Plating ATCM, unexpectedly high 

concentrations of hexavalent chromium were measured during an air monitoring study 

conducted near chromium plating facilities in San Diego. Through further air monitoring, 

the source of the high concentrations was determined to be the decorative chromium 

plating facility. 

8. Have other regulatory actions affected the chromium plating and chromic 

acid anodizing industry? 

Yes. In 2003, the South Coast Air Quality Management District (SCAQMD) adopted 

amendments to Rule 1469, entitled Hexavalent Chromium Emissions from Chromium 

Plating and Chromic Acid Anodizing Operations (SCAQMD, 2003). The amended rule 

requires hexavalent chromium facilities located within 25 meters of a sensitive receptor or 

within 100 meters of a school to reduce hexavalent chromium emissions so that the 

residential cancer risk will be no more than ten chances per million people. The rule also 

requires facilities located greater than 25 meters from a sensitive receptor or greater than 

100 meters from a school to reduce emissions such that off-site worker cancer risk would 

be no more than 25 chances per million people. The amended rule is in full effect. To 

help meet the requirements, SCAQMD staff conducted a chemical fume suppressant 

certification program which established a list of products that could be used to meet an 

emission rate of 0.01 milligrams/ampere-hour. 

As mentioned previously, a federal control measure is also in place to control emissions 

of chromium compounds from chromium plating and chromic acid anodizing facilities 

(U.S. EPA, 1995). The ARB has achieved equivalency with the Chromium Plating 

NESHAP. 

The United States Department of Labor Occupational Safety and Health Administration 

(OSHA) established a Permissible Exposure Limit (PEL) to protect workers from 
ES-5 

hexavalent chromium exposures. OSHA’s time-weighted average PEL is 5 μg/m3

, 

measured and reported as Chromium VI and an action level of 2.5 μg/m3

 for the general 

industry. 

B. The Chromium Plating and Chromic Acid Anodizing Industry in 

California 

9. What are the results of the industry survey? 

ARB staff conducted a survey of chromium plating and chromic acid anodizing facilities 

for calendar year 2003. Staff collected information on types of operations performed, 

emission rates, throughput in terms of annual ampere-hours, methods for controlling 

hexavalent chromium emissions, and economic information. Staff also conducted an 

emissions testing program to better characterize emissions of hexavalent chromium from 

decorative chromium plating operations. 

Results of our survey showed that there were 228 active facilities, and 12 of these 

conduct more than one electroplating process. These 228 facilities perform 

240 chromium related operations. This means, for example, that some facilities conduct 

both decorative and hard chromium plating. Ten operations use the trivalent chromium 

plating process to conduct decorative chromium plating. Of these ten operations, 

six facilities conduct only trivalent chromium plating. Four trivalent chromium operations 

are part of a facility that also conducts hexavalent chromium plating. The other 

230 operations use the hexavalent chromium process. Of these operations 58 are hard 

chromium plating, 127 are decorative chromium plating, and 45 are chromic acid 

anodizing operations. Our survey findings are shown graphically in Figure ES-1 below. 

Figure ES-1. Location and Type of Operation Performed at Chromium Plating and 

Chromic Acid Anodizing Facilities in California (2003) 

 

As shown in Chart A of Figure ES-1, ARB staff found that about 75 percent of facilities are 

located in the SCAQMD. Chart B shows that over half of California’s industry are 

decorative chromium plating facilities. 

Figure ES-2 shows the distribution of the 222 hexavalent chromium plating and chromic 

acid anodizing facilities based on throughput. The six facilities conducting only trivalent 

chromium plating are not represented. Throughput is presented in ampere-hours. An 

Chart A: Facility Location

BAAQMD

9%

SCAQMD

75%

SJVAPCD

7%

OTHER

9%

Chart B: Type of Operation

Anodizing

20%

Hard

25%

Decorative

55%
ES-6 

ampere-hour is a unit of amperes integrated over time. It is an important variable 

because it is used to determine the amount of hexavalent chromium emissions from a 

facility. The ampere-hours are multiplied by an emission rate to calculate emissions. 

Figure ES-2. Throughput (in Ampere-hours) for Chromium Plating and Chromic 

 Acid Anodizing Facilities in California (2003) 

48

60

45

34

15 18

0

10

20

30

40

50

60

70

Number of Facilities

< 20,000

20,000 - 200,000

200,000 - 1 Million

1 - 5 Million

5 - 15 Million

>15 Million

As shown in Figure ES-2, about 48 (about 20 percent) of facilities have annual throughput 

of 20,000 annual ampere-hours or less. Sixty facilities (27 percent) have throughput of 

between 20,000 to 200,000 annual ampere-hours. Over 50 percent of facilities have 

annual ampere-hours over 200,000. 

10. What are the results from the decorative chromium plating emissions 

 testing program? 

The goal of the emissions testing program was to establish an emission rate for chromium 

plating and chromic acid anodizing tanks controlling hexavalent chromium emissions with 

chemical fume suppressants. Staff conducted six tests to estimate emissions based on 

normal facility operations. Averaging the emission rates from these six tests results in a 

hexavalent chromium emission factor of 0.04 milligrams/ampere-hour. These data are 

representative of ‘real world’ conditions. 

Concurrent with our testing program, the SCAQMD tested the ability of chemical fume 

suppressants to reduce emissions under carefully controlled conditions. The purpose of 

this testing was to determine parameters that yielded optimum emission reductions. The 

SCAQMD demonstrated that hexavalent emissions can be further reduced if certain 

chemical fume suppressants are used. In fact, the SCAQMD demonstrated that several 

chemical fume suppressants could reduce emissions of hexavalent chromium to no more 

than 0.01 milligrams/ampere-hour. The surface tension at which this emission rate is 

achieved is at lower surface tension than currently required by the ATCM. 
ES-7 

A seventh test was done to verify the SCAQMD results. The seventh test was conducted 

using the chemical fume suppressant Fumetrol 140®. The SCAQMD certified this 

chemical fume suppressant to reduce hexavalent chromium emissions to no more than 

0.01 milligrams/ampere-hour when surface tension is maintained below 

40 dynes/centimeter. In test seven, ARB was able to duplicate this emission rate. Based 

on this test result, as well as an evaluation of the SCAQMD source test data from their 

chemical fume suppressant certification program, ARB staff determined which chemical 

fume suppressants could be used as the sole control by some facilities to comply with the 

ATCM. These chemical fume suppressants have been shown to reduce hexavalent 

chromium emissions to no more than 0.01 milligrams/ampere-hour at specified surface 

tensions. 

11. What are the emissions of hexavalent chromium from chromium plating and 

chromic acid anodizing facilities? 

Staff developed the emission inventory for chromium plating and chromic acid anodizing 

facilities by using data from the survey. As explained previously, emissions of hexavalent 

chromium are determined based on throughput and are quantified in milligrams/amperehour. To develop the emission inventory, staff developed two emission factors for 

hexavalent chromium plating facilities controlling emissions by using chemical fume 

suppressants. We estimated emissions for these facilities by using the emission rate of 

0.04 milligrams/ampere-hour for facilities outside SCAQMD. We used the emission factor 

of 0.01 milligrams/ampere-hour for SCAQMD facilities. The SCAQMD facilities are 

required to use chemical fume suppressants that meet this emission rate. Emissions 

from facilities with add-on air pollution control devices are based on source test results or 

regulatory requirements. 

Figure ES-3. Baseline Hexavalent Chromium Emissions are About Four Pounds 

 (2005) 

As shown in Figure ES-3, staff estimates that emissions of hexavalent chromium from 

chromium plating and chromic acid anodizing facilities in 2005 totaled 4.0 pounds, or 

about 1,800 grams. 

Facilities without add-on 

air pollution controls (in 

tank controls only): 

1.6 pounds per year 

Facilities with add-on air 

pollution control devices: 

2.4 pounds per year 
ES-8 

12. Why is staff concerned about 4.0 pounds per year of emissions? 

While the 4.0 pounds (1,800 grams) per year of emissions seems low, even a very small 

amount of hexavalent chromium can result in a substantial cancer risk. For example, staff 

found that as little as two grams of annual emissions would yield an estimated cancer risk 

of ten per million people exposed. As shown in Table ES-1, the maximum individual 

cancer risk (MICR) was determined for each chromium plating and chromic acid 

anodizing facility in California based on these 4.0 pounds of emissions. It should be 

noted that the MICR is calculated using the highest concentration of hexavalent chromium 

downwind of a facility that is predicted by an air quality model. People may not be living 

at the MICR point. Table ES-1 reflects implementation of the current ATCM and air 

district rules, including Rule 1469 for facilities in the South Coast Air Basin. 

Table ES-1. Sixty-three Facilities have Estimated Cancer Risk of Over 10 per Million 

Exposed People (2005 Baseline) 

 

Number of Facilities by Cancer Risk 

<1 

per million 

>1 <10 

per million 

>10 <100 

per million 

>100 

per million 

Baseline 2005 90 67 57 6 

As shown in Table ES-1, 90 facilities (about 41 percent) have estimated cancer risk less 

than one per million exposed people. However, Table ES-1 also shows that 57 facilities 

(about 26 percent) have an estimated cancer risk of over ten per million exposed people. 

Six facilities (about 3 percent) may have an estimated cancer risk of over 100 per million 

people exposed. 

Based on these results, staff determined that further risk reduction measures are 

necessary. While Rule 1469 reduced the estimated cancer risk for facilities in the 

SCAQMD, the rule had no impact on facilities in the rest of the state. We have also 

determined that Rule 1469 did not achieve the maximum reduction feasible because 

BACT was not required for all facilities. 

13. Are sensitive receptors located within 100 meters of a chromium plating and 

chromic acid anodizing facility? 

Yes. Near source exposures to chromium plating and chromic acid anodizing facilities 

are our primary health concern. ARB staff and the air districts worked together to 

determine the location of chromium plating and chromic acid anodizing facilities, and to 

determine the distance to the nearest residence, school, hospital, day care center, or 

similar sensitive receptor location. Figure ES-4 shows the proximity of facilities to 

sensitive receptors. 
ES-9 

Figure ES-4. Forty-three Percent of Facilities are Located Near 

 Sensitive Receptors 

43

26 27

126

0

20

40

60

80

100

120

140

Number of Facilities

<25 >25 <50 >50 <100 >100

Distance to Receptor (meters)

Figure ES-4 shows that 96 chromium plating and chromic acid anodizing facilities are 

located within 100 meters of a sensitive receptor. This represents 43 percent of the 

facilities. Forty-three facilities are located within 25 meters of a sensitive receptor. 

C. Staff’s Proposal to Amend the Chromium Plating ATCM 

14. How did staff determine the most effective approach to control? 

Staff evaluated available add-on air pollution control technologies and alternative 

processes for hexavalent chromium plating and chromic acid anodizing to determine if 

cancer risk could be reduced or eliminated. While alternatives exist for some 

applications, their use is limited. Thus, we concluded that alternative technologies are not 

available that enable a phase-out of the hexavalent chromium process at this time. 

However, our analysis also shows that effective add-on air pollution control devices are 

readily available. These devices minimize the cancer risk to the extent technology allows. 

Staff also conducted modeling analyses to determine how hexavalent chromium is 

dispersed from chromium plating and chromic acid anodizing facilities. The concentration 

of hexavalent chromium is highest near the facility, but the impacts of the emissions 

appear to be localized. We found that at 100 meters from the source hexavalent 

chromium concentrations are reduced by up to 90 percent. 

To develop the proposal, staff conducted the health risk assessment in a manner which is 

very health protective in estimating cancer risks for a range of reasonably foreseeable 

exposure scenarios. Staff believes this health protective approach is necessary due to 

the very high potency and resultant serious health hazards associated with hexavalent 

chromium emissions. The goal of this proposal is to reduce cancer risk to as low as 

technology allows. Use of BACT will meet this goal. 
ES-10 

15. What is best available control for (BACT) chromium plating and chromic acid 

anodizing facilities? 

Staff has evaluated various types of add-on air pollution control devices. We also have 

evaluated the effectiveness of chemical fume suppressants through our emissions testing 

program. We have determined that BACT for very small facilities is use of specific types 

of chemical fume suppressants. BACT for intermediate and larger sized facilities is use of 

add-on air pollution control devices with the final capture device being HEPA filters. Use 

of HEPA filters will reduce hexavalent chromium emissions to no more than 

0.0015 milligrams/ampere-hour. HEPA filters reduce emissions by over 99.9 percent. 

Any other combination of control devices that can meet this emission rate would be 

considered equivalent to BACT. These technologies are already employed by many 

chromium plating and chromic acid anodizing facilities. These control technologies are 

described below. 

a. Chemical Fume Suppressants 

Surface tension is the force that keeps a fluid together at the air/fluid interface. It is 

expressed in force per unit of width such as dynes/centimeter. Chemical fume 

suppressants that contain ‘wetting agents,’ or surfactants, reduce this surface tension. By 

reducing surface tension in the plating/anodizing bath, gas bubbles become smaller and 

rise more slowly than larger bubbles. Slower bubbles have reduced kinetic energy such 

that when the bubbles do burst at the surface the hexavalent chromium is less likely to be 

emitted into the air, and the droplets fall back onto the surface of the bath (Bayer®). 

The most common types of surfactants used in chromium electroplating and chromic acid 

anodizing are fluorinated or perfluorinated compounds or fluorosurfactants (U.S. EPA, 

1998). As proposed, the types of chemical fume suppressants that could be used for 

compliance with the ATCM would contain fluorosurfactants. 

b. HEPA (High Efficiency Particulate Arrestor) Filters 

HEPA filters are specifically designed for the collection of submicrometer particulate 

matter at high collection efficiencies. HEPA filters are rated at 99.97 percent effective in 

capturing particles 0.3 μm in diameter. When used in particulate air pollution control, 

HEPA filters are best utilized in applications with a low flow rate and low pollutant 

concentration. Typically, HEPA filters are installed downstream of another control device 

to lessen loading on the filter, thereby lengthening its life. HEPA filters are considered the 

most effective control of hexavalent chromium emissions from chromium plating and 

chromic acid anodizing. 

16. What are the goals of the proposed amendments? 

The goals of the proposed amendments are to achieve the maximum hexavalent 

chromium emission reduction from chromium plating and chromic acid anodizing facilities, 

ensure that new facilities are isolated from sensitive receptors, and reduce fugitive 

hexavalent chromium emissions. 
ES-11 

17. How would the proposed amendments achieve these goals? 

The proposed amendments would require use of BACT for all facilities. Use of HEPA 

filters, or other combinations of controls that are as effective as HEPA filters, represent 

BACT for intermediate and large throughput facilities. BACT for very small facilities is the 

use of ARB specified chemical fume suppressants. The requirements would be phased 

in based on throughput and proximity to sensitive receptors. Sensitive receptor locations 

include residences, schools, daycare centers, hospitals, hospices, retirement or nursing 

homes, prisons and dormitories. 

The proposal would also prevent new hexavalent chromium plating and chromic acid 

anodizing facilities from operating in areas zoned as residential or mixed use or within 

150 meters (~500 feet) of these zones. Any new facility would also be required to install 

state-of-the-art add-on air pollution control devices prior to beginning operations. 

Proposed housekeeping provisions would reduce fugitive emissions of hexavalent 

chromium from all facilities by establishing housekeeping measures. 

18. What would the proposed amendments require for existing hexavalent 

chromium plating and chromic acid anodizing facilities? 

Staff is proposing to amend the Chromium Plating ATCM by phasing in BACT. The 

timing for application of BACT would be related to throughput and proximity to sensitive 

receptors. The requirements and timing are shown in Table ES-2 below. 

Table ES-2. Proposed Hexavalent Chromium Emission Limits for Existing Facilities 

Tiers of 

Annual 

Permitted 

Ampere-Hours

Sensitive 

Receptor 

Distance 

Emission Limitation Effective Date 

Tier 1 

≤ 20,000 Any 

Use Chemical Fume Suppressant as 

specified in section 93102.8 

[Six Months after 

Effective Date] 

Tier 2 

> 20,000 and 

≤ 200,000 

< 100 

Meters 

0.0015 milligrams/ampere-hour [Two Years after 

Effective Date] 

Tier 3 

> 20,000 and 

≤ 200,000 

> 100 

Meters 

0.0015 milligrams/ampere-hour [Five Years after 

Effective Date] 

Tier 4 

> 200,000 

Any 0.0015 milligrams/ampere-hour [Two Years after 

Effective Date] 

As shown in Table ES-2, very low throughput (less than 20,000 ampere-hours per year) 

facilities would be required, at a minimum, to reduce hexavalent chromium emissions 

through use of specified chemical fume suppressants to lower surface tension of the 

plating or anodizing bath. This represents BACT for these facilities, and would generally 

ensure that the maximum cancer risk near the facility is under one in a million. 
ES-12 

Intermediate-sized facilities (greater than 20,000 but less than 200,000 ampere-hours per 

year) would be required to meet an emission limitation of 0.0015 milligrams/ampere-hour. 

These facilities, however, would have the option to demonstrate compliance without 

installation of add-on air pollution control devices. This proposal, along with providing 

additional time to comply for those facilities more than 100 meters from a sensitive 

receptor, could reduce compliance costs for some small businesses. 

The largest facilities (more than 200,000 ampere-hours per year) would be required to 

comply with the emission limitation of 0.0015 milligrams/ampere-hour within two years 

using an add-on air pollution control device(s). After application of BACT, facilities with 

remaining cancer risk over 25 per million exposed people would be required to conduct a 

site specific analysis of their facility’s risk to determine if further control measures are 

necessary. 

19. What would the proposed amendments require for any new facility? 

The proposal would prevent new chromium plating or chromic acid anodizing facilities 

from operating in areas zoned residential or mixed use or within 150 meters (~500 feet) of 

an area zoned residential or mixed use. At this distance, modeling for point sources 

shows that the hexavalent chromium concentration has dropped off by about 80 percent. 

New facilities would also be required to conduct a site specific analysis to ensure their 

emissions do not cause adverse impacts. 

20. What is staff proposing to limit fugitive emissions?

Fugitive dust emissions also likely impact people residing near chromium plating and 

chromic acid anodizing facilities. Therefore, staff is proposing that all facilities implement 

housekeeping measures to reduce dust emissions. 

21. Are other changes proposed? 

Yes. Training explaining the Chromium Plating ATCM and the requirements, conducted 

by ARB staff, would be required for employees responsible for compliance every 

two years. The training offered by SCAQMD would fulfill this requirement. 

The proposal would also prohibit the sale or use of chromium plating or chromic acid 

anodizing materials unless sold or used by individuals or businesses under air district 

permit to conduct such operations. 

Staff is proposing to require use of specific types of chemical fume suppressants for 

complying with the surface tension limits. The chemical fume suppressants that could be 

used have been shown to reduce hexavalent chromium emissions to more than 

0.01 milligrams/ampere-hour at the proposed surface tensions. 

To implement the new hexavalent chromium emission reduction requirements, a definition 

for “sensitive receptor” is proposed. A "sensitive receptor" is proposed to be defined as 

“any residence including private homes, condominiums, apartments, and living quarters; 
ES-13 

education resources such as preschools and kindergarten through grade twelve (k-12) 

schools; daycare centers; and health care facilities such as hospitals or retirement and 

nursing homes. A "Sensitive Receptor" includes individuals housed in long term care 

hospitals, hospices, prisons, and dormitories or similar live-in housing.” 

D. Health Benefits Resulting from the Proposed Amendments 

Adoption of the proposed amendments would significantly reduce both emissions and 

cancer risk from chromium plating and chromic acid anodizing facilities. 

22. How would emissions and cancer risk be reduced if the staff’s proposal were 

to be adopted? 

If the staff’s proposal were to be adopted, an additional 40 percent of facilities would be 

reducing emissions by over 99 percent. Estimated cancer risk for residents and off-site 

workers living or working near chromium plating and chromic acid anodizing facilities 

would be reduced by up to 85 percent depending on the individual facility. 

Table ES-3 below shows how excess cancer risk would be reduced beyond the risk 

reduction achieved by implementation of current ARB and district rules. 

Table ES-3. Adoption of Staff’s Proposal Significantly Reduces the Estimated Cancer 

Risk from Hexavalent Chromium Emissions 

 Number of Facilities by Cancer Risk 

<1 

per million 

>1 <10 

per million 

>10 <100 

per million 

>100 

per million 

Staff Proposal 162 41 17 0 

Baseline 90 67 57 6 

As shown in Table ES-3, by adopting the staff’s proposal about 162 facilities (74 percent) 

would have remaining cancer risk of no more than one per million exposed persons. This 

represents an additional 72 facilities compared to the baseline. Only 17 facilities (about 

8 percent) would have estimated cancer risk of over ten per million exposed people. No 

facilities would have cancer risk exceeding 100 per million exposed people. Under the 

staff’s proposal each facility with residual cancer risk over 25 per million exposed people 

would need to do a site specific analysis to determine if further control measures are 

needed. Total hexavalent chromium emissions from all chromium plating and chromic 

acid anodizing facilities would decrease, by 55 percent, to 1.8 pounds per year. 

Non-cancer health risks were also evaluated. Our analysis found that each facility’s 

hazard index was well below the level of concern (hazard index = 1). Adoption of the 

proposal would only lower further the potential for any adverse non-cancer effects to 

occur. 
ES-14 

E. Public Outreach 

23. In developing the proposal what actions did staff take to consult with all 

stakeholders? 

Staff worked with the air districts, industry, the environmental community, and other 

affected parties through public workshops, meetings, telephone calls, and mail-outs. 

Major outreach activities included: 

• Forming an ARB/Air District Working Group; 

• Forming an ARB/Stakeholder Working Group and conducting meetings in Northern 

and Southern California; 

• Conducting site visits to numerous chromium plating and chromic acid anodizing 

operations; 

• Creating a website and maintaining a List-Serve to automatically update interested 

parties about proposed ATCM developments; 

• Conducting surveys of chromium plating and chromic acid anodizing facilities, 

chemical fume suppressant manufacturers providing chemicals and services to the 

chromium plating and chromic acid anodizing facilities in California, and conducting 

an economic survey of the industry; 

• Mailing workshop notices and posting workshop materials on ARB’s website; 

• Conducting public workshops, with conference call tie-in, in Northern and Southern 

California; and 

• Preparing a fact sheet regarding the development of the proposed ATCM and 

making it available to the public. 

F. Economic Impacts of the Staff’s Proposal 

Staff has evaluated the financial impact on California businesses that would result from 

adoption of the proposed amendments. Staff conducted a very conservative cost impact 

assessment. While some businesses may be able to demonstrate compliance without 

purchasing a HEPA system, it was assumed for the purpose of our economic impact 

analysis that all facilities required to meet the 0.0015 milligrams/ampere-hour limit would 

purchase a HEPA filtration system. 

24. How many businesses are impacted by the staff’s proposal? 

All of the 226 facilities affected by the proposed amendments to the ATCM will have some 

compliance costs. [Two facilities have closed down since conducting the survey.] Up to 

89 facility owners would be required to expend significant capital to meet the 

requirements. About 60 percent of facilities however, are already in substantial 

compliance. 
ES-15 

25. What would be an individual facility’s cost to comply? 

During the first year, all facilities would have compliance costs. Costs will vary depending 

on the extent an individual business is already in compliance with the proposed 

amendments. We estimate that costs in the first year would range from 

$450 to $217,000, with an average cost of $23,000. In subsequent years, costs would 

range from near zero to $217,000, with an average cost of $53,000. After the first year, 

60 percent of the facilities would have no additional compliance costs. 

26. How would the Return on Owner’s Equity be affected? 

All of the chromium plating and chromic acid anodizing businesses affected by these 

proposed amendments are California businesses. Businesses are affected by the 

proposed amendments to the extent that costs associated with implementation of the 

regulation may reduce their profitability. 

Profitability impacts were estimated by calculating the decline in the return on owner’s 

equity (ROE). A decline in ROE of 10 percent or more is one indication that the ATCM 

could result in a significant adverse impact. The proposed amendments to the ATCM are 

expected to result in an average ROE decline of nine percent. 

Staff has determined that costs for some individual businesses are expected to be 

significant and would adversely impact their profitability. For the 89 businesses that 

would likely need to install or upgrade add-on air pollution control devices, the estimated 

decline in profitability ranges from 3 to 41 percent. Twenty-eight of these are small 

businesses. The average estimated compliance cost for these businesses is about 

$53,000. Some smaller volume plating or anodizing businesses may decide to cease 

chromium plating or anodizing operations rather than make the investments needed to 

comply. 

27. Is there any assistance available to help small businesses secure the 

necessary capital to comply? 

The Governor, in 2005, signed legislation (Assembly Bill 721, Nunez) to establish a loan 

guarantee program for decorative chromium plating operations to purchase pollution 

control equipment. The program is administered by the Business, Transportation, and 

Housing Agency. The program will provide loan guarantees of up to $100,000 to owners 

of decorative chromium plating small businesses that are not able to qualify for a 

conventional loan. The loan guarantee program is now in effect. In July 2006, the 

Governor signed into law amendments to the loan guarantee program. The loan 

guarantee program is now available for all metal plating facilities. 

 

28. Are manufacturers of chromium plating and chromic acid anodizing 

suppliers adversely impacted by the proposed amendments? 

We do not expect manufacturers of chromium plating and chromic acid anodizing 

materials to incur any costs. However, the staff’s proposal to prohibit sales of chromium 
ES-16 

plating kits to non-permitted facilities may result in lost revenue for these businesses. 

The proposed amendments would potentially impact the chemical manufacturers in a 

positive way through increased sale of chemical fume suppressants. Add-on air pollution 

control device manufacturers, as well as the metal fabricating industry would also benefit 

from the proposed amendments as controls and ductwork for ventilation systems is 

purchased. 

29. Would consumers be impacted by the proposal? 

The potential impact of the proposed amendments to the ATCM on consumers depends 

upon the extent to which affected businesses are able to pass on the increased cost to 

consumers in terms of higher prices for their goods and services. If all costs are passed 

onto the consumers, we expect the cost per ampere-hour to increase from near zero to 

about $2.20 per ampere-hour. These costs are estimated based on facilities that would 

have to install add-on air pollution control devices. The lower end of this cost would 

represent a large throughput facility, while the upper end cost would represent a small 

throughput facility. 

To put these costs into perspective, consider that chromium plating an automobile 

bumper (a decorative chromium application) requires 50 ampere-hours to chromium 

plate. This would mean the increased cost to plate a bumper would increase from near 

zero to about $110. If re-plating a bumper costs $400 at present time, the cost of the 

bumper would increase from about $400 to as much as $510. 

30. Are there any costs to public agencies? 

Yes. The air districts, as a result of the proposed amendments, would incur costs for 

reviewing initial compliance status reports; reviewing or revising permit modifications for 

facilities adding or upgrading to HEPA, or an equivalent level of control; reviewing source 

test protocols and results; and reviewing site specific analyses, if necessary. We 

estimate the new costs to air districts resulting from the proposed amendments to the 

ATCM to be approximately $685,000. However, air districts can recover these costs 

through fees charged to the facilities. 

31. What are the total costs of the proposed amendments to the Chromium 

Plating ATCM? 

Total capital costs for purchase of add-on air pollution control devices are estimated at 

$9.6 million. Total recurring costs are estimated at $3.6 million. An additional $1.0 million 

in costs is estimated for reports, source testing, permit fees, and site specific analyses. In 

total costs are estimated to be $14.2 million. 
ES-17 

G. Evaluation of Alternatives 

32. What alternatives to the proposed amendments to the Chromium Plating 

ATCM did staff consider?

Staff considered four alternatives to the proposed amendments. The alternatives were 

evaluated in terms of applicability, risk reduction, enforceability, and cost. 

a. Require decorative chromium plating facilities to use the trivalent 

chromium plating process 

One alternative to the staff’s proposal would be to require the use of the trivalent 

chromium plating process for all decorative chromium plating facilities. Requiring all 

decorative chromium facilities to use the trivalent chromium process would eliminate the 

remaining cancer risk from the hexavalent chromium emissions from decorative 

chromium plating facilities. Staff has evaluated the trivalent chromium process and has 

determined that it is not a universal replacement for all decorative chromium plating 

applications. Therefore, staff has determined this is not a technologically feasible 

alternative. 

b. Require HEPA filtration systems, or an equivalent add-on air pollution 

control device, for all facilities 

Another alternative would be to require installation of HEPA filtration systems, or an 

equivalent add-on air pollution control device for all facilities. Staff determined that this 

alternative would result in no appreciable additional benefit because the very small 

facilities would have estimated cancer risk of no more than one per million exposed 

people after implementation of the proposal. This option would add additional equipment 

costs of over $4.0 million. As a result staff chose not to pursue this alternative. 

 c. Adopt the provisions of SCAQMD Rule 1469 statewide 

A third alternative considered was to adopt the provisions of SCAQMD Rule 1469 

statewide. In 2003, the SCAQMD amended its Rule 1469, Control of Hexavalent 

Chromium Emissions from Chrome Plating and Chromic Acid Anodizing Operations 

(Rule 1469). The rule requires hexavalent chromium facilities located within 25 meters of 

a sensitive receptor or within 100 meters of a school to reduce hexavalent chromium 

emissions such that the residential cancer risk will be no more than ten chances per 

million people. The rule also requires facilities located greater than 25 meters from a 

sensitive receptor or 100 meters from a school to reduce emissions such that off-site 

worker cancer risk would be no more than 25 chances per million people. The amended 

rule is in full effect. 

Staff has evaluated this alternative and has found it does not provide the level of 

protection that would be achieved through adoption of the staff’s proposal. Such an 

approach would not ensure that BACT is applied at all facilities. ARB staff has 

determined that BACT for very small facilities (≤ 20,000 ampere-hour throughput) is use 
ES-18 

of specific types of chemical fume suppressants. BACT for intermediate and larger 

facilities is use of add-on air pollution control devices with the final capture device being 

HEPA filters, or any other combination of controls that are as effective as HEPA filters. 

 d. Require no further control 

Alternative 4 would be to require no additional control. Staff does not believe the status 

quo is protective of public health especially considering that 43 percent of operations are 

located within 100 meters of a sensitive receptor. Our goal is to achieve the maximum 

feasible health protection—especially when people are living, learning, working, or playing 

near chromium plating and chromic acid anodizing facilities. Thus, staff did not choose 

this alternative. 

 e. Summary 

Table ES-4 compares alternatives three and four with the staff’s proposal. Alternatives 

one and two are not presented. Alternative one is not technologically feasible. 

Alternative two essentially offers no benefit beyond the staff’s proposal. 

Table ES-4. Adoption of Staff’s Proposal Offers the Greatest Reduction in Significant 

Community Cancer Risk 

 Number of Facilities by Cancer Risk 

<1 

per million 

>1 <10 

per million 

>10 <100 

per million 

>100 

per million 

Staff Proposal 162 41 17 0 

Rule 1469 

Statewide 98 67 53 2 

Baseline 90 67 57 6 

Table ES-4 shows that the staff’s proposal offers the best health protection. As shown, 

adopting the provisions of SCAQMD Rule 1469 statewide would result in 98 facilities 

(about 45 percent) with remaining cancer risk of no more than one per million exposed 

persons. This represents an additional 8 facilities compared to the baseline. Adoption of 

the staff’s proposal would reduce the estimated cancer risk for 162 facilities (about 

74 percent) to no more than one per million exposed persons. 

Table ES-4 also shows that if the provisions of Rule 1469 were to be adopted statewide, 

53 facilities (about 24 percent) would continue to have estimated cancer risk of over ten 

per million exposed people, and two facilities would have estimated cancer risk of over 

100 per million exposed people. If the staff’s proposal were adopted, 17 facilities (about 

8 percent) would have estimated cancer risk of over ten per million exposed people and 

no facilities would have cancer risk exceeding 100 per million exposed people. Under the 

staff’s proposal each facility with residual cancer risk over 25 per million would need to do 

a site specific analysis to determine if further control measures are needed. 
ES-19 

 f. Conclusion 

We evaluated each of the alternatives and concluded that the alternatives did not meet 

the objective of Health and Safety Code section 39666 to reduce emissions to the lowest 

level achievable in consideration of cost, health risk, and environmental impacts. Staff 

believes the proposed amendments represent the best balance between costs and 

cancer risk. 

H. Environmental Impacts 

33. What are the expected environmental benefits if the proposed amendments 

are adopted?

The primary benefit from the proposed amendments is a large reduction in excess cancer 

risk from emissions of hexavalent chromium. We estimate that an additional 40 percent 

of facilities would be controlling emissions by over 99 percent and cancer risk would be 

reduced by up to 85 percent for individual facilities. Almost 75 percent of facilities would 

have cancer risk of less than one per million people exposed. Ninety-two percent of 

facilities would have cancer risk of less than ten per million people exposed. The 

proposal will also have a direct benefit for low income and ethnically diverse communities 

that may be heavily impacted by hexavalent chromium emissions from chromium plating 

and chromic acid anodizing operations. 

34. Are there any significant adverse environmental impacts that would result 

from adopting the proposed amendments? 

No. We evaluated the potential impacts on air quality, water and wastewater, and 

hazardous waste. We also evaluated the effect on the environment of the use of 

chemical fume suppressants. 

Air Quality. The proposed amendments to the ATCM would result in a negligible 

improvement in air quality in terms of the weight of the emissions. While the proposed 

amendments reduce emissions of hexavalent chromium by about 55 percent, the actual 

reduction in mass is about 2.2 pounds per year. Remaining emissions are estimated to 

be 1.8 pounds per year. 

It is also anticipated that there will be a temporary increase in emissions of criteria 

pollutants due to construction related activity involved in the installation of new add-on air 

pollution controls and the possible dismantling of current controls. 

Water and Wastewater. Many of the add-on air pollution control devices required by the 

proposed amendments require periodic water washdown to clean and maintain the 

integrity of the system. Implementation of housekeeping measures would likely require 

fresh water usage as well. The increased water usage is difficult to quantify. However, 

we do not expect the increased use to be significant. We expect the amount of 

wastewater to also increase due to the proposed amendments related to housekeeping 

and equipment maintenance. Compliance with State Water Resources Control Board 
ES-20 

regulations would prevent this hexavalent chromium from being discharged to lakes, 

rivers, bays, or oceans. 

Hazardous waste. The proposed amendments would require an additional 

89 facilities to begin using add-on air pollution control devices with the final collection 

mechanism likely to be HEPA filters. These filters, as well as pre-filters designed to 

increase the useful life of HEPA filters, are considered hazardous waste to be disposed of 

in Class A landfills. HEPA filters are usually replaced at least annually, but replacement 

schedules depend upon the individual operation. Pre-filters are replaced more often. 

Assuming a typical filter volume of 4 cubic feet each, the resulting volume of hazardous 

waste generated is 2.9 cubic feet per day. We do not consider this to be a significant 

increase in the amount of hazardous waste to be landfilled. 

In California, all hazardous waste must be disposed of at a facility that is registered with 

the Department of Toxic Substances Control (DTSC). Chromium plating and chromic 

acid anodizing facility wastes are classified as hazardous waste because they contain 

hexavalent chromium. 

Use of Bioaccumulative Compounds. The fluorosurfactants used as active ingredients in 

chemical fume suppressants are often referred to as perfluorooctyl sulfonates (PFOS). 

While these products are highly effective at reducing hexavalent chromium emissions by 

reducing plating bath surface tension the compounds have been shown to be persistent, 

bioaccumulative, and toxic to mammals. Studies indicate that PFOS may have potential 

developmental, reproductive, and systemic toxicity (U.S. EPA, 2006). These compounds 

are being evaluated for addition to a Significant New Use Rule for perfluoroalkyl 

sulfonates (PFAS). Based on the staff’s proposal we estimate a maximum increased use 

of chemical fume suppressants of about three gallons per year. 

We expect these impacts to be minimal and believe that the significant reduction in 

cancer risk overrides any small adverse impact that would result from adoption of the 

staff’s proposal. 

35. Are any reasonably foreseeable mitigation measures necessary? 

No. The California Environmental Quality Act requires an agency to identify and adopt 

feasible mitigation measures that would minimize any significant adverse environmental 

impacts described in the environmental analysis. The ARB staff has concluded that no 

significant adverse environmental impacts should occur from adoption of and compliance 

with the proposed amendments to the ATCM. Because no significant adverse impacts 

have been identified, no specific mitigation measures would be necessary. 

36. Are there any reasonably foreseeable alternative means of compliance with 

the proposed amendments to the airborne toxic control measure? 

Alternatives to the proposed amendments to the Chromium Plating ATCM are discussed 

in question 32. The ARB staff has concluded that the proposed amendments to the 

ATCM provide the most effective and least burdensome approach to reducing the public’s 
ES-21 

exposure to hexavalent chromium emitted from chromium plating and chromic acid 

anodizing facilities. 

37. How does the staff’s proposal relate to ARB’s community health and 

environmental justice programs? 

Environmental Justice is defined as the fair treatment of people of all races, cultures, and 

incomes with respect to the development, adoption, implementation, and enforcement of 

environmental laws, regulations, and policies. The ARB is committed to integrating 

environmental justice into all of our activities. The proposed amendments to the ATCM 

are consistent with our policies to reduce health risks from toxic air pollutants in all 

communities, including those with low-income and ethnically diverse populations, 

regardless of location. Potential health risks from hexavalent chromium emissions from 

chromium plating and chromic acid anodizing operations can affect both urban and rural 

communities. Therefore, reducing hexavalent chromium emissions from chromium 

plating and chromic acid anodizing operations will provide air quality benefits to urban and 

rural communities in the State, including low-income areas and ethnically diverse 

communities. 

We have identified several communities that may be heavily impacted by hexavalent 

chromium emissions from chromium plating and chromic acid anodizing operations. The 

residents in these communities would realize a large portion of the benefits of the 

proposal. 

To further address environmental justice and the public’s concern regarding exposure to 

hexavalent chromium emissions, the proposed amendments to the ATCM would specify 

that any new facility would not be able to operate in any area zoned as residential or 

mixed use, or within 150 meters of a residential or mixed use zone. 

I. Recommendation 

We recommend that the Board adopt the proposed amendments to the Chromium Plating 

ATCM. Staff has determined that the proposed amendments are necessary to reduce 

cancer risk from hexavalent chromium emissions from chromium plating and chromic acid 

anodizing facilities. If adopted, about 75 percent of facilities would have estimated cancer 

risk of no more than one per million exposed people. Ninety-two percent of facilities 

would have estimated cancer risk of no more than ten per million exposed people. Staff 

also believes the proposal represents a balance between health risk and cost. The 

proposed amendments are contained in Appendix A. 

Within six months of the amendments becoming legally effective, the air districts would be 

required to implement and enforce the proposed amendments to the ATCM or adopt an 

equally effective measure. 
ES-22 

REFERENCES 

Bayer ®. Product information Bayowet® FT 248 and FT 248R. 

SCAQMD, 2003. South Coast Air Quality Management District. Rule 1469: “Hexavalent 

Chromium Emissions from Chrome Plating and Chromic Acid Anodizing Operations”. 

Amended May 2, 2003 

U.S. EPA, 1995. U.S. Environmental Protection Agency. 40 CFR Part 63 Subpart N: 

“National Emission Standards for Chromium Emissions From Hard and Decorative 

Chromium Electroplating and Chromium Anodizing Tanks”. 1995. 

U.S. EPA, 1998. U.S. Environmental Protection Agency. EPA/625/R-98/002: “Capsule 

Report Hard Chrome Fume Suppressants and Control Technologies”. 1998. 

U.S. EPA, 2006. U.S. Environmental Protection Agency. 40 CFR Part 721: 

“Perfluoroalkyl Sulfonates; Proposed Significant New Use Rule.” 2006. 
Chapter I Page 1 

I. Introduction 

Hexavalent chromium plating, or simply chromium plating, is the electrical application of a 

coating of chromium onto a surface for decoration, corrosion protection, or for durability. 

An electrical charge is applied to a tank (bath) containing an electrolytic salt (chromium 

anhydride) solution. The electrical charge causes the chromium metal particles in the 

bath to fall out of solution and deposit onto objects placed into the plating solution. During 

chromic acid anodizing, an oxidation layer is generated on the surface of the part. These 

electrolytic processes cause mists containing hexavalent chromium to be ejected from the 

plating tank which are eventually dispersed into outdoor ambient air. 

Hexavalent chromium is a potent known human carcinogen. Consequently, the California 

Air Resources Board (ARB or Board) has regulated the hexavalent chromium emissions 

from chromium plating and chromic acid anodizing facilities since 1988. The existing 

control measure, the Hexavalent Chromium Airborne Toxic Control Measure for Chrome 

Plating and Chromic Acid Anodizing Operations (ATCM or Chromium Plating ATCM), is 

found in title 17, California Code of Regulations, section 93102. 

ARB staff has determined that despite significant reductions, people living near chromium 

plating and chromic acid anodizing facilities are still exposed to unnecessarily high 

concentrations of hexavalent chromium. Therefore, this Initial Statement of Reasons sets 

forth the staff’s proposal to amend the ATCM (contained in Appendix A) and the rationale 

for the proposal. 

A. Overview 

In 1986, based on a recommendation by the Scientific Review Panel (SRP) on Toxic Air 

Contaminants (TACs), the Board identified hexavalent chromium as a TAC (ARB, 1985). 

Hexavalent chromium was determined to be a potent human carcinogen with no known 

safe level of exposure. Subsequent to that finding, the Board adopted measures to 

control hexavalent chromium emissions, including an ATCM to reduce hexavalent 

chromium emissions from chromium plating and chromic acid anodizing operations. This 

ATCM reduced hexavalent chromium emissions from chromium plating and anodizing 

facilities by well over 90 percent. 

While an over 90 percent reduction is significant, because of the potent carcinogenicity of 

hexavalent chromium, even minute amounts are cause for concern, particularly for nearsource receptors. Hexavalent chromium emissions of as little as two grams per year can 

result in an estimated cancer risk of ten per million people exposed. Because of the 

potential for near-source unacceptable residual health risks, staff undertook an evaluation 

of the chromium plating and chromic acid anodizing industry and the existing ATCM to 

ensure that it continues to provide the maximum feasible health protection. These 

amendments are being proposed as a result of that evaluation. ARB staff has 
Chapter I Page 2 

reviewed control technologies, emissions, population exposures, and remaining health 

risks, and has found that further control is feasible and warranted. This Initial Statement 

of Reasons (ISOR or Staff Report) sets forth the staff’s proposal to amend the Chromium 

Plating ATCM and outlines the need and rationale for the proposal. This staff report for 

the proposed amendments includes: 

• Background regulatory information and authority; 

• Goals of the regulation and public outreach; 

• Chromium plating and chromic acid anodizing industry characterization; 

• Findings from the Industry Survey, Chemical Manufacturers Survey, Economic 

Survey, and Receptor Proximity Survey; 

• Emission factor development and the decorative chromium plating emissions testing 

program; 

• Potential exposure and risk from chromium plating and chromic acid anodizing 

operations; 

• Availability and technological feasibility of potential control devices; 

• Description of the proposed amendments; 

• Economic impacts of the proposed amendments; and 

• Environmental impacts of the proposed amendments. 

B. Goals of the Proposed Amendments 

The goal of the proposed amendments to the Chromium Plating ATCM is to minimize the 

public’s exposure to hexavalent chromium emissions from chromium plating and chromic 

acid anodizing facilities. The amendments are designed to achieve the maximum 

hexavalent chromium emission reductions by using the most reliable controls available. 

The amendments are also designed to isolate people from new facilities. If adopted, the 

amendments would set more stringent requirements for all intermediate and large 

hexavalent chromium plating and chromic acid anodizing facilities by requiring best 

available add-on air pollution control technology (BACT). We have determined that BACT 

for very small facilities is the use of specific types of chemical fume suppressants. The 

requirements would be phased in based on throughput and proximity to sensitive 

receptors. Sensitive receptor locations include residences, schools, daycare centers, 

hospitals, hospices, retirement or nursing homes, prisons, and dormitories. 

The proposal would also prevent new chromium plating and chromic acid anodizing 

facilities from operating in areas zoned as residential or mixed use or within 150 meters 

(~500 feet) of these zones. Any new facility would also be required to install state-of-theart add-on air pollution control devices prior to beginning operations. 

Proposed housekeeping provisions would also reduce fugitive emissions of hexavalent 

chromium from all facilities by establishing housekeeping measures. Personnel at plating 

operations would also be required to undergo ARB-sponsored training to ensure that 

parameter monitoring and recordkeeping are done properly. The amendments would 

also prevent sale of chromium plating chemicals and equipment to any individual that was 

not the owner or operator of a permitted facility. 
Chapter I Page 3 

The existing ATCM requirements are different based on the type of operation (decorative 

plating and anodizing or hard chromium plating). Under this proposal, all facilities using 

the hexavalent chromium process regardless of type of operation would be subject to the 

same control requirements. The proposed amendments are contained in Appendix A. 

Adoption of the staff’s proposal would result in reducing cancer risk by up to 85 percent 

for individual facilities. 

If adopted by the Board, the amended control measure would be implemented and 

enforced by the air pollution control and air quality management districts (air districts). 

The air districts may implement the proposed amendments to the ATCM, as adopted by 

the Board, or adopt an alternative rule at least as stringent as the ARB's ATCM. 

C. Regulatory Authority 

Legislation enacted in the 1980’s delegated to ARB the authority and responsibility to 

identify and control toxic air contaminants. This section outlines the statutory authority to 

control toxic substances and includes a description of the processes that have been 

developed to fulfill the requirements of State law. 

The ARB's statewide air toxics program was established in the early 1980's. Assembly 

Bill (AB) 1807 (Tanner, Chapter 1047, statutes 1983), The Toxic Air Contaminant 

Identification and Control Act, created California's Toxic Air Contaminant Identification 

and Control Program (Air Toxics Program) to reduce the public's exposure to air toxics. 

This law is codified in Health and Safety Code sections 39650 through 39675. AB 2588 

(Connelly, Chapter 1252, statutes of 1987), Air Toxics "Hot Spots" Information and 

Assessment Act, supplements the Air Toxics Program by requiring a statewide air toxics 

inventory, notification of people exposed to a significant health risk, and facility plans to 

reduce these risks. 

1. Identification and Control of Toxic Air Contaminants 

The Air Toxics Program established a two step process to identify and then control air 

toxics to protect the health of Californians. 

In the first step, a substance is formally identified as a TAC based on reviews by the ARB 

and the Office of Environmental Health Hazard Assessment (OEHHA). The agencies 

evaluate the health impacts of, and exposure to, substances, and identify as TACs those 

substances that pose the greatest health threat. The ARB's evaluation is made available 

to the public and is formally reviewed by the SRP on TACs established under Health and 

Safety Code section 39670. Following the ARB's evaluation and the SRP's review, the 

Board, at a public hearing, may formally identify a TAC. 
Chapter I Page 4 

In the second step, risk reduction, the ARB reviews the emission sources of a TAC to 

determine what regulatory actions are available and necessary to maximize health 

protection. Health and Safety Code sections 39658, 39665, 39666, and 39667 require 

ARB, with the participation of the air districts, and in consultation with affected sources 

and interested parties, to prepare a report on the need and appropriate degree of 

regulation for a TAC. In situations where no safe threshold level is found for a particular 

TAC, the control measures are to be designed to reduce emissions to the lowest level 

achievable through application of BACT or a more effective control method in 

consideration of health risk to the public and cost. 

 2. The “Hot Spots” Program

Under the AB 2588 program, stationary sources are required to report the types and 

quantities of certain substances that their facilities routinely release into the air. The 

goals of the "Hot Spots" Act are to collect emission data, identify facilities having localized 

impacts, determine health risks, and notify nearby residents of significant risks. In 

September 1992, the "Hot Spots" Act was amended by SB 1731 to address the reduction 

of significant risks. The bill requires that owners of significant-risk facilities reduce their 

risks below the level of significance as determined by air districts. Chromium plating and 

anodizing operations are subject to the “Hot Spots” program, and, as described below, 

are also subject to a technology-based ATCM to minimize emissions of hexavalent 

chromium. 

3. Identification and Control of Hexavalent Chromium

In 1986, ARB identified hexavalent chromium as a TAC after peer review by the SRP. 

Hexavalent chromium was determined to be a potent known human carcinogen with a 

cancer unit risk factor of 1.5 X 10-1 microgram per cubic meter (μg/m3

) of air. This 

potency factor means that exposure to 1 μg/m3 of hexavalent chromium over a lifetime 

would potentially result in 146,000 excess cancer cases per million exposed people. The 

Board also found that the available scientific evidence did not support a hexavalent 

chromium threshold exposure level below which significant adverse health effects would 

not be expected (title 17, California Code of Regulations, section 93000). Also, at this 

time, the Board did not find sufficient evidence to identify trivalent chromium as a TAC 

(ARB, 1985). 

To reduce the risk from hexavalent chromium, the Board has adopted four ATCMs: 

• 1988 - Hexavalent Chromium Airborne Toxic Control Measure for Chrome 

Plating and Chromic Acid Anodizing Operations (ARB, 1988);

• 1989 - Airborne Toxic Control Measure for Hexavalent Chromium For Cooling 

Towers (ARB, 1989); 

• 2001 - Airborne Toxic Control Measure for Emissions of Hexavalent Chromium 

and Cadmium From Motor Vehicle and Mobile Equipment Coatings 

(ARB, 2001); 

• 2005 – Airborne Toxic Control Measure to Reduce Emissions of Hexavalent 

Chromium and Nickel From Thermal Spraying (ARB, 2005).
Chapter I Page 5 

This report describes staff’s proposal to further reduce the public’s exposure to 

hexavalent chromium from chromium plating and chromic acid anodizing facilities. To 

better understand the proposal it is important to first understand the requirements of the 

current ATCM. 

D. Existing State Control Measure 

The State’s existing Chromium Plating ATCM was originally adopted in 1988 and 

amended in 1998. The regulation is set forth in title 17, CCR, section 93102. The ATCM 

adopted in 1988 set technology-based standards that focused primarily on hard chromium 

plating facilities and set limits based on BACT at that time. Implementation of this 

regulation resulted in hexavalent chromium emission reductions of over 90 percent. A 

brief summary of the requirements for the existing ATCM follows: 

• Hard chromium plating facilities are required to install add-on air pollution control 

devices to meet emission limits ranging from 0.15 milligrams/ampere-hour 

(mg/amp-hr) to 0.006 milligrams/ampere-hour, depending on levels of throughput. 

An alternative surface tension limit was provided for hard chromium plating 

facilities with throughput levels of 500,000 ampere-hours or less; and 

• Decorative plating and anodizing facilities must comply with either an emission limit 

using add-on air pollution controls or meet a surface tension limit. Most facilities 

comply by meeting the surface tension limit. 

The ATCM also has recordkeeping requirements and operation and maintenance 

requirements. However, the existing ATCM does not take into account proximity of 

existing chromium plating and chromic acid anodizing facilities to people. 

The ATCM was amended in 1998 to establish equivalency with the National Emission 

Standards for Chromium Emissions from Hard and Decorative Chromium Electroplating 

and Chromium Anodizing Tanks (Chromium Plating NESHAP) (U.S. EPA, 1995). The 

federal Chromium Plating NESHAP included control requirements for trivalent chromium 

operations because it is a hazardous air pollutant (HAP). Therefore, the focus of ARB's 

1998 amendments was to include provisions for controlling emissions from trivalent 

chromium plating facilities (ARB, 1998). Also, prior to these amendments, chromic acid 

anodizing facilities were required to comply with the same provisions as hard chromium 

plating facilities. These amendments provided that chromic acid anodizing facilities could 

comply with the surface tension limit alone rather than the previous emission rate limit. 

Other conforming changes included: 

• Parameter Monitoring requirements; 

• Inspection and Maintenance requirements; 

• Operation and Maintenance Plan requirements; 

• Recordkeeping requirements; and 

• Reporting requirements. 
Chapter I Page 6 

E. Federal Regulations 

Because the ARB has achieved equivalency with the Chromium Plating NESHAP for 

chromium plating and chromic acid anodizing facilities, California’s facilities are only 

required to comply with the State’s ATCM (Approval of section 112 (l) Authority of 

Hazardous Air Pollutants; Chromium Emissions from Hard and Decorative Chromium 

Electroplating and Chromium Anodizing Tanks; State of California; Approved 

December 16, 1998, Volume 63, number 241, Page 69251-69256) (U.S. EPA, 1998a). 

However, a description of United States Environmental Protection Agency’s (U.S. EPA) 

Chromium Plating NESHAP, as well as the Occupational Safety and Health 

Administration’s (OSHA) permissible exposure level for hexavalent chromium is useful to 

understand how chromium plating facilities and chromic acid anodizing facilities are 

regulated. 

1. Chromium Plating NESHAP

The 1990 federal Clean Air Act Amendments established a list of Hazardous Air 

Pollutants (HAPs) and directed the U.S. EPA to set standards for all major sources of air 

toxics. “Chromium Compounds,” including hexavalent chromium and trivalent chromium 

are listed as HAPs. [In 1992, California AB 2728 (Tanner, Chapter 1161, statutes of 

1992) specified that ARB must, by regulation, identify as TACs the 189 substances 

identified by the federal government as HAPs.] 

For certain designated source categories, U.S. EPA has developed specific regulations 

referred to as the National Emission Standards for Hazardous Air Pollutants (NESHAPs). 

In January 1995, the U.S. EPA promulgated, in 40 Code of Federal Regulations (CFR) 

Part 63, Subpart N, the Chromium Plating NESHAP. Concentration standards were 

established for hard chromium plating facilities. These limits could be met by the addition 

of forced ventilation systems, but add-on air pollution control devices were not necessarily 

needed. Surface tension limits were established for decorative chromium plating facilities 

and chromic acid anodizing facilities (U.S. EPA, 1995). 

On July 19, 2004, the U.S. EPA amended the Chromium Plating NESHAP. The changes 

are summarized below. 

• Allowed the use of chemical fume suppressants to control chromium emissions 

from hard chromium plating facilities as an alternative to the existing concentration 

emission limit; 

• Provided an alternative standard to the existing concentration emission limit for 

hard chromium plating tanks equipped with enclosed hoods; 

• Modified surface tension parameter testing to accommodate the differences in 

measurement between the use of a stalagmometer and the tensiometer 

(stalagmometer requirement: < 45 dynes/centimeter; tensiometer requirement: 

< 35 dynes/centimeter); 

• Expanded the definition of “chromium electroplating and anodizing” to include all of 

the ancillary hardware associated with the plating process. This includes such 
Chapter I Page 7 

items as the tank, “add-on” control equipment, rectifier, process tanks, ductwork, 

etc.; and 

• Amended the pressure drop for composite mesh pads to ±2 inches of water 

column instead of ±1 inch of water column (U.S. EPA, 2004).

 2. Federal OSHA Worker Exposure Limits

Under the U.S. Department of Labor, OSHA published a Permissible Exposure Limit 

(PEL) to protect workers from hexavalent chromium exposures. The exposures to 

hexavalent chromium are addressed in specific standards for maritime, construction, and 

general industries. 

OSHA's PEL for chromic acid and chromates is found in 29 CFR 1910.1000, Table Z-2. 

On February 28, 2006, OSHA changed the hexavalent chromium rule by setting a timeweighted average PEL of 5 μg/m3

, measured and reported as Chromium VI, and an 

action level of half the PEL for the general industry. OSHA also adopted other ancillary 

provisions for employee protection such as preferred methods for controlling exposure, 

respiratory protection, protective work clothing and equipment, establishing hygiene areas 

and practices, medical surveillance, hazard communication, and recordkeeping 

(OSHA, 2006). More information can be found at the following webpage: 

http://www.osha.gov/SLTC/hexavalentchromium/standards.html. 

F. Current Air District Rules 

As required by State law, air districts are required to adopt, implement, and enforce rules 

that are equivalent to any State adopted ATCM, or may elect to adopt a rule that is more 

stringent. The air districts also are required to gather from facilities emissions information 

required by the “Hot Spots” Act. Some air districts also have adopted rules or policies 

that require existing facilities to reduce health risks below an air district specified level of 

significance. New facilities generally are not allowed to operate unless the potential 

health risk posed by the facility’s emissions is below the air district’s level of significance. 

Chromium plating and chromic acid anodizing facilities operate under permits issued by 

each air district. Table I-1 lists air districts that have active chromium plating and/or 

chromic acid anodizing facilities and the rule with which facilities in that air district must 

comply. 
Chapter I Page 8 

Table I-1. Air Districts with Active Chromium Plating and/or Chromic Acid Anodizing 

 Facilities and Corresponding Prohibitive Rule 

District Rule 

Bay Area Air Quality Management District (BAAQMD) Rule 11.8 

Feather River Air Quality Management District (FRAQMD) Rule 11.2 

South Coast Air Quality Management District (SCAQMD) Rule 1469 

Sacramento Metropolitan Air Quality Management District 

(SMAQMD) 

Rule 904 

San Diego County Air Pollution Control District 

(SDCAPCD) 

Rule 1201 

San Joaquin Valley Air Pollution Control District 

(SJVAPCD) 

Rule 7011 

Shasta County Air Quality Management District Rule 3:11 

Ventura County Air Pollution Control District (VCAPCD) Chromium Plating 

ATCM 

Of particular interest for this rulemaking is the May 2003 amendments to Rule 1469 

adopted by the South Coast Air Quality Management District (SCAQMD), Hexavalent 

Chromium Emissions from Chrome Plating and Chromic Acid Anodizing Operations 

(SCAQMD, 2003). These changes were designed to further reduce health risk by 

specifying lower emission rates for all facilities, and establishing more stringent 

requirements for facilities located near sensitive receptors than were in place at the time. 

The goal was to specify emission rates to reduce the potential cancer risk from all 

facilities below the air district’s level of significance, a potential cancer risk of no more 

than 25 per million persons. However, more stringent requirements were specified for 

facilities located within 25 meters of a sensitive receptor, or 100 meters of an existing 

school. In these instances, potential cancer risks were to be reduced below ten per 

million persons. A summary of the changes is provided below: 

• Set more stringent mass emission limits with increasing ampere-hours and 

distance to receptor; 

• Established a fume suppressant certification program and an emission rate of 

0.01 milligrams/ampere-hour for certified fume suppressants; 

• Added housekeeping practices for all facilities; 

• Prohibited the air sparging of chromium plating or anodizing tanks, unless in use; 

• Prohibited removal of existing add-on air pollution control equipment, unless 

replaced with air pollution control techniques meeting higher control efficiencies; 

• Provided optional emission limits for small facilities; 

• Added alternative compliance options for all facilities; and 

• Established an operator training requirement. 

As part of the “Hot Spots” program, air districts have developed rules or policies designed 

to further reduce health risks from sources of toxic air pollutants. These rules are 

triggered at air district specified levels of significance and apply to both new and existing 
Chapter I Page 9 

facilities. These rules establish the health risk levels that trigger the need for installation 

of BACT for Toxics (T-BACT). Generally, new facilities are subject to the more stringent 

requirements. All of these rules and policies have been useful in our evaluation of 

measures that are feasible to further reduce health risk from chromium plating and 

chromic acid anodizing operations. A synopsis of some of these rules is provided below. 

SCAQMD Rule 1401, New Source Review of Toxic Air Contaminants applies to air 

permits for new, relocated, or modified sources that emit TACs. If the potential increase 

in cancer risk from a modification does not exceed one case per one million persons, 

T-BACT controls are not required to obtain an air permit. If the potential increase in 

cancer risk is between 1 and 10 per million persons, T-BACT controls are required to 

obtain an air permit. In addition, the cancer burden must not exceed 0.5 cases 

(SCAQMD, 1990). 

SCAQMD Rule 1402, Control of Toxic Air Contaminants from Existing Sources, specifies 

an action risk level of 25 excess cases per million persons for cancer risk, a cancer 

burden of 0.5, or a total acute or chronic hazard index of 3.0 for any target organ system 

at any receptor location. [An acute or chronic hazard index is the ratio of the estimated 

level of exposure over a specified period of time to its acute or chronic reference 

exposure level.] Existing facilities that exceed the action risk level must develop risk 

reduction plans and implement measures to reduce risks to below the action level. The 

amendments to Rule 1469 were designed as an alternative for chromium plating and 

chromic acid anodizing facilities to meet the requirements of Rule 1402 (SCAQMD, 1994). 

San Diego County Air Pollution Control District (SDCAPCD) Rules 1200, Toxic Air 

Contaminants – New Source Review, and 1210, Toxic Air Contaminant Public Health 

Risks – Public Notification and Risk Reduction, specify that if the potential increase in 

cancer risk does not exceed one per million persons, T-BACT controls are not required to 

obtain an air permit. If the potential increase in cancer risk is between 1 and 10 per 

million persons, T-BACT controls are generally required to obtain an air permit. If the 

potential increased cancer risk is greater than 10 but no more than 100 per million 

persons, it may still be possible to get an air permit if a facility can meet specific 

conditions (SDCAPCD, 1996). 

The Bay Area Air Quality Management District (BAAQMD) does not have a specific rule 

for toxics permitting. However, BAAQMD’s permitting policy is generally consistent with 

the SCAQMD and SDCAPCD toxics new source review rules. All permit applications for 

new or modified sources are screened for emissions of TACs and sources that may 

present significant health risks are required to install T-BACT to minimize TAC emissions 

(BAAQMD, 2005). 

G. Barrio Logan, A Case Study of Near Source Impacts 

In May of 2001, ARB, with cooperation of the SDCAPCD, began monitoring around two 

chromium plating facilities in the Barrio Logan neighborhood of San Diego. A residence 

was located between these facilities and numerous residences were in the area. Local 

concern about possible exposures to hexavalent chromium emissions from these 
Chapter I Page 10 

facilities, as well as, the Children’s Environmental Health Protection Act [Senate Bill 25, 

Escutia 1999 (SB 25)] prompted the study. SB 25 required ARB to evaluate the air that 

children are exposed to in places where they live and play and to determine if current 

regulations adequately protect them. One facility was a hard chromium plating operation 

with emissions controlled by a HEPA filter system. The other facility was a decorative 

plating operation with emissions controlled by using a chemical fume suppressant to 

reduce the surface tension of the plating bath. 

In January 2002, unexpectedly high levels of hexavalent chromium were found at a 

number of monitoring sites. More intensive monitoring pinpointed the source of the 

elevated levels of hexavalent chromium to be from the decorative chromium plating 

facility. Through this study, we also found that fugitive dust emissions from the facility 

contributed to community hexavalent chromium exposures. For more detailed 

information, please refer to the Barrio Logan Report, “A Compilation of Air Quality Studies 

in Barrio Logan, November 2004” (ARB, 2004). The report can be found at the following 

address: http://www.arb.ca.gov/ch/programs/bl_11_04.pdf 

H. Hexavalent Chromium Emissions Study and Conclusions 

The results of air monitoring for hexavalent chromium in Barrio Logan indicated that 

emissions from decorative chromium plating facilities may be underestimated. To 

investigate this theory, we undertook a hexavalent chromium emissions testing program 

at decorative chromium plating facilities in various parts of the State to evaluate the 

emission factor for facilities using only in-tank controls. As a result of this testing, the 

emission factor for chemical fume suppressant controlled facilities (those complying with 

the surface tension limit1

) has been revised and is used in this report to assess emissions 

of, and exposure to, hexavalent chromium from these facilities. 

Through our evaluation, we have found that there are remaining significant public health 

risks associated with hexavalent chromium emissions from chromium plating and chromic 

acid anodizing facilities, especially when facilities are located near homes or schools. In 

assessing existing, readily available, control technologies for chromium plating and 

chromic acid anodizing facilities, staff believes further control is feasible and necessary to 

protect the health of California’s residents, by reducing exposure to hexavalent chromium. 

 

1

Chemicals are added to the plating bath that reduce surface tension. Surface tension reductions also reduce 

hexavalent chromium emissions.
Chapter I Page 11 

REFERENCES

ARB, 1985. Air Resources Board. “Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking – Public Hearing to Consider the Adoption of a Regulatory 

Amendment Identifying Hexavalent Chromium as a Toxic Air Contaminant”. 1985. 

ARB, 1988. Air Resources Board. “Final Regulation Order – Hexavalent Chromium 

Airborne Toxic Control Measure (ATCM) for Chrome Plating and Chromic Acid Anodizing 

Operations”. 1988. 

ARB, 1989. Air Resources Board. “Final Regulation Order – Chromate Treated Cooling 

Towers”. 1989. 

ARB, 1998. Air Resources Board. “Staff Report – Proposed Amendments to the 

Hexavalent Chromium Control Measure For Decorative and Hard Chrome Plating and 

Chromic Acid Anodizing Facilities”. 1998. 

ARB, 2001. Air Resources Board. “Final Regulation Order - Airborne Toxic Control 

Measure for Emissions of Hexavalent Chromium and Cadmium From Motor Vehicle and 

Mobile Equipment Coatings”. 2001. 

ARB, 2004. Air Resources Board. “Barrio Logan Report: A Compilation of Air Quality 

Studies in Barrio Logan”. 2004. 

ARB, 2005. Air Resources Board. “Final Regulation Order - Airborne Toxic 

Control Measure to Reduce Emissions of Hexavalent Chromium and Nickel from Thermal 

Spraying”. 2005. 

BAAQMD, 2005. Bay Area Air Quality Management District. Regulation 2 Permits Rule 

5: “New Source Review of Toxic Air Contaminants”. 2005. 

OSHA, 2006. Occupational Safety and Health Administration. 29 CFR Parts 1910, 1915, 

1917, 1918, and 1926, “Occupational Exposure to Hexavalent Chromium; Final Rule”. 

2006 

SCAQMD, 1990. South Coast Air Quality Management District. Rule 1401: “New 

Source Review of Toxic Air Contaminants”. 1990 

SCAQMD, 1994. South Coast Air Quality Management District. Rule 1402: “Control of 

Toxic Air Contaminants from Existing Sources”. 1994 

SCAQMD, 2003. South Coast Air Quality Management District. Rule 1469: “Hexavalent 

Chromium Emissions from Chrome Plating and Chromic Acid Anodizing Operations”. 

Amended May 2, 2003 
Chapter I Page 12 

SDCAPCD, 1996. San Diego Air Pollution Control District: Rule 1200: “Toxic Air 

Contaminants – New Source Review”. Revised June 12, 1996 

U.S. EPA, 1995. U.S. Environmental Protection Agency. 40 CFR Part 63 Subpart N: 

“National Emission Standards for Chromium Emissions From Hard and Decorative 

Chromium Electroplating and Chromium Anodizing Tanks”. 1995. 

U.S. EPA, 1998a. U.S. Environmental Protection Agency. 40 CFR Part 63: “Approval of 

Section 112(I) Authority for Hazardous Air Pollutants; Chromium Emissions from Hard 

and Decorative Chromium Electroplating and Chromium Anodizing Tanks; State of 

California”. 1998. 

U.S. EPA, 2004. U.S. Environmental Protection Agency. 40 CFR Part 63: “National 

Emission Standards for Chromium Emissions From Hard and Decorative Chromium 

Electroplating and Chromium Anodizing Tanks”. 2004. 
Chapter II Page 13 

II. Need for Further Regulation 

In 1986, the Board identified hexavalent chromium as a Toxic Air Contaminant (TAC). 

Hexavalent chromium was determined to be an extremely potent human carcinogen with 

no known safe level of exposure. The Board found that exposure over a lifetime to very 

low ambient hexavalent chromium concentrations could substantially increase a person’s 

chance of developing cancer from exposure to the hexavalent chromium emissions. 

Based on this finding, in 1988 the Board adopted a very stringent ATCM which resulted in 

reducing hexavalent chromium emissions from chromium plating and chromic acid 

anodizing facilities by well over 90 percent. While an over 90 percent reduction is 

significant, even minute amounts are cause for concern, particularly for near-source 

receptors because of the potent carcinogenicity of hexavalent chromium. 

Ambient levels of hexavalent chromium measured from our air toxics monitoring network 

are routinely low, with many measurements below the level of detection. Thus, the 

general public’s exposure to ambient hexavalent chromium concentrations is not 

considered significant. However, near-source exposures can be significant. In 2002, 

SCAQMD conducted limited ambient air sampling around several chromium plating and 

chromic acid anodizing facilities. Based on this monitoring, estimated cancer risks from 

five facilities ranged from 20 to 55 per million people exposed. Four facilities had cancer 

risks of less than ten per million exposed people. One facility had an estimated cancer 

risk of 450 per million exposed people (SCAQMD, 2003a). [SCAQMD worked with the 

facility with cancer risk of 450 per million exposed people to reduce the risk.] Although 

these data were collected prior to implementation of Rule 1469, the results demonstrate 

that measurable and elevated concentrations of hexavalent chromium are found near 

these sources. Due to implementation of SCAQMD Rule 1469, these estimated cancer 

risks from the facilities tested could be lower. 

Information from our Barrio Logan study reinforce findings that hexavalent chromium 

emissions from chromium plating and chromic acid anodizing operations are measurable, 

but highly localized. The Barrio Logan study, also showed that dust containing 

hexavalent chromium can contribute to ambient, near-source concentrations. This result 

was confirmed by follow-up sampling conducted by the SDCAPCD. These fugitive 

emissions can not be quantified for all facilities, but could increase the cancer risk beyond 

what is calculated based on emissions from the plating operation alone. 

Our modeling analyses also indicate that near-source concentrations are, in many cases, 

significant. Hexavalent chromium emissions of as little as two grams per year can result 

in an estimated cancer risk of ten per million people exposed. Thus, staff has found that 

emissions from some facilities still result in unacceptable health risks to near-by 

receptors. Based on our evaluation of chromium plating and chromic acid anodizing 

facilities, we found that it is common to find sensitive receptors near these facilities. In 

fact, we found that 43 percent of facilities are located within 100 meters of a sensitive 

receptor. For all of these reasons, staff has determined that, despite the fact that 

significant emissions reductions have been achieved, there is a need to further reduce 

emissions, if technologically feasible. 
Chapter II Page 14 

This Chapter contains a general summary of the physical and chemical characteristics of 

hexavalent chromium and chromium compounds. Emissions and sources of hexavalent 

chromium, as well as health effects from exposure to hexavalent chromium are also 

provided. For ease of the reader, we have summarized some of the information from 

earlier reports, and have updated information where appropriate. For further information, 

the reader is referred to the following documents: 

• Staff Report: Initial Statement of Reasons for Proposed Rulemaking – Identification 

of Hexavalent Chromium as a Toxic Air Contaminant (ARB,1985); 

• Proposed Hexavalent Chromium Control Plan (ARB, 1988a); 

• Initial Statement of Reasons for Proposed Rulemaking – Proposed Airborne Toxic 

Control Measure for Emissions of Hexavalent Chromium from Chrome Plating and 

Chromic Acid Anodizing Operations (ARB, 1988b); 

• Proposed Hexavalent Chromium Control Measure for Cooling Towers 

(ARB, 1989a); 

• Toxic Air Contaminant Identification List Summaries (ARB, 1997); 

• Airborne Toxic Control Measure for Emissions of Hexavalent Chromium and 

Cadmium from Motor Vehicle and Mobile Equipment Coatings: Initial Statement of 

Reasons for Proposed Rulemaking Executive Summary/Staff Report (ARB, 

2001a); and 

• Airborne Toxic Control Measure to Reduce Emissions of Hexavalent Chromium 

and Nickel from Thermal Spraying Initial Statement of Reasons for Proposed 

Rulemaking (ARB, 2004a). 

In support of the need for further regulation, this Chapter also contains a synopsis of our 

Barrio Logan study findings and results from our survey to determine proximity of 

sensitive receptors to hexavalent chromium plating and chromic acid anodizing facilities. 

A. Characteristics, Sources, and Ambient Concentrations of 

Hexavalent Chromium and Chromium Compounds 

The chromium compounds of interest for this staff report are the TACs hexavalent 

chromium and trivalent chromium. Because hexavalent chromium is a TAC and has been 

identified as a human carcinogen with no known safe exposure level (ARB, 1985), the 

focus of the staff’s proposal is to further reduce hexavalent chromium emissions from 

chromium plating and chromic acid anodizing facilities. 

Trivalent chromium has been identified as a TAC by virtue of it being a hazardous air 

pollutant (HAP). By comparison to hexavalent chromium, it poses lesser health hazards. 

It is not a human carcinogen. Health hazards associated with use of trivalent chromium 

are presented to put these hazards in perspective to the health hazards associated with 

use of hexavalent chromium. Due to the comparatively lower toxicity impact, staff 

believes trivalent chromium plating (for decorative plating) to be a safer alternative to 

hexavalent chromium plating. In fact, the trivalent chromium chemistry is already 

successfully in use at several California decorative chromium plating facilities. However, 
Chapter II Page 15 

although improvements in the process have been made, use of trivalent chromium is not 

available for all applications. 

1. Chemistry

Trivalent chromium occurs naturally in the mineral chromite (chrome ore). It is from 

chromite that chromium metal and other chromium compounds are formed. Of the 

various chromium oxidation states, trivalent chromium is the most stable. Hexavalent 

chromium is the cation of a metal salt and does not occur naturally. Generally, 

hexavalent chromium ions are produced under strong oxidizing conditions from metallic 

chromium, with the most common ions being chromate ion (CrO4

-2) or dichromate ion 

(Cr2O7

-2). Hexavalent chromium ions are strong oxidizing agents and are readily reduced 

to trivalent chromium in acid or by organic matter (ARB, 1997). 

 2. Sources and Emissions 

Chromium plating, chromic acid anodizing, thermal spraying, and firebrick lining of glass 

furnaces are all stationary sources of hexavalent chromium in California. In California, 

stationary sources are estimated to emit about 1,000 pounds per year of hexavalent 

chromium. Approximately 0.13 tons/year are emitted by gasoline vehicles and 

0.83 tons/year by other mobile sources such as trains and ships (ARB, 2006a). 

Chapter V describes the emissions of hexavalent chromium in California from chromium 

plating and chromic acid anodizing facilities. 

Based on staff’s survey of the chromium plating and chromic acid anodizing industry it 

appears data used to compile the 2006 Almanac emission inventory overestimated the 

hexavalent chromium emissions contributed by chromium plating and chromic acid 

anodizing facilities. In the 2006 Almanac, emissions from chromium plating and chromic 

acid anodizing facilities were estimated to be about 30 pounds. Since publication of the 

2006 Almanac, updated emission inventory information has resulted in a revision of the 

earlier estimate of 30 pounds to about 4.5 pounds. We estimate, based on our survey, 

that in 2005 emissions from chromium plating and chromic acid anodizing facilities were 

about four pounds. These data are provided in Chapter V. Information from the survey, 

along with updated emissions estimates from local air districts and other sources, will be 

used as the basis for emissions estimates in future Almanacs. Emission inventories are 

dynamic and are ‘snapshots’ in time. This reduction in hexavalent chromium plating and 

chromic acid anodizing facility emissions, that will be reflected in the next Almanac, will 

not appreciably reduce the total statewide stationary source estimated emissions. 

3. Ambient Concentrations

Chromium compounds and hexavalent chromium are routinely monitored as part of the 

statewide ARB air toxics network. This monitoring meets U.S. EPA’s standards for 

ambient monitoring. It does not reflect near source exposures which may be significant. 

Trivalent chromium compounds are not specifically monitored, but are accounted for as a 

fraction of total chromium. The monitoring results indicate that hexavalent chromium 
Chapter II Page 16 

concentrations have declined in recent years. The statewide mean concentration of 

hexavalent chromium has decreased from 0.27 nanograms per cubic meter (ng/m3

) in 

1992 to 0.091 ng/m3 in 2005. For hexavalent chromium ambient monitoring, the limit of 

detection has also decreased from 0.2 ng/m3 in 1992 to 0.06 ng/m3 in 2002. Therefore, 

the mean concentrations for 2002 and later are based on more precise measurements of 

ambient concentrations (ARB, 2006a). 

Table II-1 shows the hexavalent chromium mean concentration at various monitoring sites 

in air districts with chromium plating and anodizing facilities (ARB, 2006b). 

Table II-1. Hexavalent Chromium Mean Concentration in Air Districts with 

 Chromium Plating and Anodizing Facilities for the Year 2005

District ARB’s Air Toxics 

Network Monitoring Site 

Mean Concentration 

(ng/m3

)

South Coast Air Quality 

Management District

Azusa-803 Loren Ave. 0.08 

Burbank – W. Palm Ave. 0.113 

North Long Beach 0.10 

San Diego County Air 

Pollution Control District

Chula Vista 0.038 

El Cajon-Redwood 

Avenue 

0.048 

Ventura County Air 

Pollution Control District

Simi Valley-Cochran 

Street 

0.05 

Bay Area Air Quality 

Management District

Fremont-Chapel Way 0.05 

San Francisco-Arkansas 

Street 

0.11 

San Joaquin Valley Air 

Pollution Control District

Fresno-1st Street 0.063 

Stockton-Hazelton Street 0.12 

Sacramento 

Metropolitan Air Quality 

Management District 

Roseville-N Sunrise Blvd 0.058 

As shown in Table II-1, mean concentrations range from 0.038 to 0.12 ng/m3

 in 2005. 

These values would yield a range of estimated cancer risk of about 6 per million to 

18 per million people exposed. 

The mean concentrations may be overestimated. This is because prior to 2002 

monitoring results below the limit of detection are assumed to be one-half the limit of 

detection or 0.1 ng/m3 (ARB, 2006a). Our ambient monitoring data show that the 

percentage of measurements that were below the detection limits increased steadily over 

the years, reaching a peak of over 96 percent in 1999. Starting in 2002, analysis was 

performed on composite samples representative of one quarter. This lowered the 

detection limit to 0.06 ng/m3

. Even with this lowering of the detection limit, the percentage 

of measurements below the detection limit has been steady at around 28 percent. 
Chapter II Page 17 

Therefore, we conclude that ambient concentrations of hexavalent chromium are low and 

are not a general public health concern. From these ambient data we are also able to 

infer that the emissions from chromium plating and chromic acid anodizing facilities are a 

near source-concern. As further support, in the SCAQMD ambient monitoring mentioned 

earlier, concentrations measured downwind of 10 chromium plating and chromic acid 

anodizing facilities ranged from 0.03 ng/m3

 to 2.99 ng/m3, with an average of 0.44 ng/m3 

(SCAQMD, 2003a). 

 

 4. Indoor Sources and Concentrations

The extent of exposure to airborne hexavalent chromium in the indoor environment, other 

than in the workplace, is not known. There are no direct consumer uses of chromium that 

could lead to indoor emissions of hexavalent chromium compounds. During the 

emissions testing program conducted by the ARB, staff placed ambient air monitors 

inside the plating shops that were being source tested. Indoor levels of hexavalent 

chromium detected in the chromium plating facilities tested without forced ventilation 

systems in place ranged from four to 2,350 ng/m3

. These data are qualitative and the 

numbers should not be used as indoor air concentration numbers. However, the numbers 

clearly indicate that hexavalent chromium is emitted from plating tanks, and is present as 

an airborne particle. These data are presented in Chapter V. 

Environmental Tobacco Smoke is known to contain hexavalent chromium in the 

particulate matter components (ARB, 2005a) The Board identified environmental tobacco 

smoke as a TAC in January 2006. 

 5. Atmospheric Persistence

Atmospheric reactions of chromium compounds were characterized in field reaction 

studies and laboratory chamber tests. These results demonstrated an average 

experimental half-life of 13 hours (ARB, 1997). Based on this, one would expect there to 

be minimal amounts of hexavalent chromium in the dust found in and around the plating 

facilities. However, during ARB’s Barrio Logan study and later during a 

SDCAPCD study, indoor dust was collected at plating shops to determine if hexavalent 

chromium was present. Results of dust sample analyses indicated that hexavalent 

chromium was indeed present in the dust samples. Hexavalent chromium concentrations 

in samples collected near the plating tank ranged from 407 to 89,800 milligrams per 

kilogram. These results are summarized in Appendix G. 

 

6. Particle Size of Hexavalent Chromium

The potential of hexavalent chromium to become airborne and disperse into ambient air is 

dependent on particle size. If the particles are large, they would likely not become 

airborne, or if they would become airborne they would rapidly deposit. Our indoor air data 

collected during the emissions testing program demonstrate that hexavalent chromium is 

present in ambient air inside the facilities. Our modeling analyses in Chapter VII are 

based on hexavalent chromium particles being small enough to behave as a gas such 

that they are emitted into ambient air. To verify this, we consulted the U.S. EPA’s AP 42 
Chapter II Page 18 

document and found that generally hexavalent chromium particles are eight micrometers 

or smaller in diameter. Particles of this size are thought to behave as a gas 

(U.S. EPA, 1996). Thus, we conclude that the modeling analyses accurately predict how 

hexavalent chromium is dispersed into the outside ambient air. 

B. Health Impacts 

Health Impacts of hexavalent chromium have been well documented. The ARB and 

U.S. EPA have identified hexavalent chromium as a TAC and HAP respectively. It is 

widely recognized as a potent human carcinogen with no known level of safe exposure. 

When hexavalent chromium was identified as a TAC, OEHHA developed a cancer 

potency value of 0.15 (μg/m3)

-1 that was approved by the SRP on TACs. This value 

means that a person’s chance of developing cancer due to exposure to 1 μg/m3 of 

hexavalent chromium over a 70 year lifetime would be 146,000 chances per million 

people, almost 15 percent (ARB, 1985). Only one other identified TAC, dioxin, has been 

determined more likely to cause cancer than hexavalent chromium. 

Unlike hexavalent chromium, trivalent chromium is not considered to be a human 

carcinogen (U.S. EPA, 2000). Results from a study published in 2000 documented that 

hexavalent chromium caused an increased incidence of lung cancer in a group of 

2,357 workers at a chromate production plant. Cumulative hexavalent chromium 

exposure was associated with an increased lung cancer risk, while cumulative trivalent 

exposure was not (AJIM, 2000). The U.S. EPA published another report that 

distinguishes the health impacts of the two oxidation states of chromium. In that report, 

hexavalent chromium is described as a “Group A known human carcinogen,” while 

trivalent chromium “is much less toxic and is recognized as an essential element in the 

human diet.” Trivalent chromium is “a Group D Carcinogen, not classifiable as to 

carcinogenicity in humans” (U.S. EPA, 2000). 

Trivalent chromium is also markedly less potent in causing other toxic effects. While 

some adverse effects on the lung, kidney, and reproductive system have been reported in 

animal studies, and in studies of humans occupationally exposed to trivalent chromium 

compounds, the doses required to produce these effects are high. These doses were 

generally at least ten times higher than those for corresponding effects of hexavalent 

chromium (ATSDR, 2000). Some of this difference is apparently due to the poor 

absorption of trivalent chromium from the lung or digestive system, and its much reduced 

ability (compared to hexavalent chromium) to move from extracellular body fluids into 

cells of potentially sensitive tissues. 

While the chemistry and toxicology of hexavalent chromium and trivalent chromium are 

markedly different, trivalent chromium is not without toxic effects and still should be 

handled appropriately. 
Chapter II Page 19 

C. Barrio Logan: A Case Study of Near Source Impacts 

1. Background

Findings from an air monitoring study conducted by ARB in the Barrio Logan community 

in San Diego provide one important basis for our proposal. Barrio Logan is a residentialcommercial area with single-family homes and apartments located in close proximity to 

light industrial facilities, including two chromium plating businesses. Many of the families 

living near the chromium plating shops include children and the elderly. In addition to the 

plating shops, there are approximately twelve single family residences, a cabinet shop, a 

neighborhood youth center, and a community swimming pool. 

In May 2001, the ARB began monitoring around the two chromium plating facilities. One 

facility was a hard chromium plating facility with add-on air pollution control devices, 

including a HEPA filter and forced ventilation system. The other facility was a decorative 

chromium plating shop with in-tank controls (chemical fume suppressant) and no forced 

ventilation system. The chromium plating facilities were close to multiple residences and 

a community youth center and the community was concerned about hexavalent chromium 

emissions from these facilities. Thus, the ARB staff designed a receptor-oriented 

sampling study focusing on airborne hexavalent chromium concentrations. 

The monitoring study also allowed us to evaluate the effectiveness of the existing 

Chromium Plating ATCM in providing public health protection, especially in community 

settings where residences and sensitive receptors are in close proximity to emission 

sources. 

2. Air Monitoring

Air monitoring to determine hexavalent chromium ambient air concentrations began in 

May 2001 and continued periodically until May of 2002. Analysis of air samples, collected 

during monitoring from December 3 through December 17, 2001, found some unusually 

high hexavalent chromium levels (nine samples had results greater than 3.0 ng/m3) in the 

immediate vicinity of the plating shops and residences. The average of all 24-hour 

ambient samples was 0.98 ng/m3 (ARB, 2003). To put this in perspective, the statewide 

annual average hexavalent chromium concentration in 2005 is 0.091 ng/m3. The highest 

24-hour ambient hexavalent chromium value recorded in ARB’s statewide toxics network 

was 22 ng/m3 measured on February 20, 1995, in Burbank in the South Coast Air Basin. 

The next highest values statewide were 9.9 ng/m3in 1991 and 3.0 ng/m3 in 1992. 

Further sampling was conducted to identify the source or sources of the emissions and 

the specific activities leading to the high concentrations of hexavalent chromium found in 

December 2001. Follow-on sampling began on February 5 and ran daily through 

May 24, 2002, to identify the source of the emissions and to address the public health 

concern associated with the ambient hexavalent chromium levels. In addition to air 

monitoring, we also conducted compliance inspections, dust and soil sampling, a source 

test, indoor air sampling at the plating shops, extensive area walks and inspections, and 

air dispersion modeling. 
Chapter II Page 20 

3. Summary of Results and Findings

Analysis of samples implicated the decorative chromium plating operation as the source 

of the high ambient hexavalent chromium measurements. The data also showed that it 

was not only emissions from the daily plating process that were the cause of the high 

ambient hexavalent chromium readings. We also found that fugitive hexavalent 

chromium laden dust, that had accumulated within the shop was escaping through 

building openings and contributing to elevated outdoor hexavalent chromium 

concentrations (ARB, 2004). 

This study was important to the evaluation of the Chromium Plating ATCM because 

results indicated that: 

• Hexavalent chromium emissions from decorative chromium plating facilities may 

be underestimated; 

• Poor ‘housekeeping’ practices may lead to fugitive hexavalent chromium 

emissions; 

• Hexavalent chromium emissions from chromium plating create a local impact, a 

“Hot Spot,” but the hexavalent chromium concentration drops off quickly; and 

• Emissions from the HEPA controlled hard chromium plating facility were effectively 

reduced and not contributing to elevated levels of hexavalent chromium in the 

neighborhood. 

D. Proximity of Facilities to Sensitive Receptors 

 

As part of our evaluation, we collected data to determine proximity of sensitive receptors 

to all chromium plating and chromic acid anodizing shops. We learned from the Barrio 

Logan study that the receptors nearest volume emission sources (source without add-on 

air pollution control) are most affected. 

ARB staff worked with the air districts to obtain receptor information for all chromium 

plating and chromic acid anodizing facilities. In instances when data were not available, 

ARB staff visited facilities and determined the distance to the nearest sensitive receptor. 

We are proposing to define sensitive receptor as a residence including private homes, 

condominiums, apartments, and living quarters; education resources such as preschools 

and kindergarten through twelve (K-12) schools; daycare centers; and health care 

facilities such as hospitals or retirement and nursing homes. A sensitive receptor would 

include long term care hospitals, hospices, prisons, and dormitories or similar live-in 

housing. 

Out of 222 hexavalent chromium plating and chromic acid anodizing facilities, 19 percent 

are located within 25 meters of a sensitive receptor. We also found that 96 facilities 

(43 percent) are located within 100 meters of a sensitive receptor. Air quality modeling 

results, found in Chapter VII, indicate that receptors located within 100 meters of a 
Chapter II Page 21 

chromium plating operation (volume source) may be exposed to significant levels of 

hexavalent chromium. The detailed data on proximity of sensitive receptors to chromium 

plating and chromic acid anodizing facilities are summarized in Chapter IV. 

These data point to the need to further control hexavalent chromium emissions to protect 

near-source receptors, especially sensitive receptors such as children and the elderly. 
Chapter II Page 22 

REFERENCES 

AJIM, 2000. American Journal of Industrial Medicine. HJ Gibb, PSJ Lees, PF Pinsky & 

BC Rooney. Lung Cancer Among Workers in Chromium Chemical Production. 38:115-

126. 2000. 

ARB, 1985. Air Resources Board. “Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking – Public Hearing to Consider the Adoption of a Regulatory 

Amendment Identifying Hexavalent Chromium as a Toxic Air Contaminant”. 1985. 

ARB, 1988a. Air Resources Board. “Technical Support Document to Proposed 

Hexavalent Chromium Control Plan”. 1988. 

ARB, 1988b. Air Resources Board. “Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking – Proposed Airborne Toxic Control Measure for Emissions of 

Hexavalent Chromium from Chrome Plating and Chromic Acid Anodizing Operations”. 

1988. 

ARB, 1989a. Air Resources Board. “Proposed Hexavalent Chromium Control Measure 

For Cooling Towers”. 1989. 

ARB, 1997. Air Resources Board. “Toxic Air Contaminant Identification List –

Summaries – Chromium and Compounds Hexavalent Chromium”. 1997. 

ARB, 2001a. Air Resources Board. “Airborne Toxic Control Measure For Emissions Of 

Hexavalent Chromium And Cadmium From Motor Vehicle And Mobile Equipment 

Coatings: Initial Statement Of Reasons For Proposed Rulemaking. Executive 

Summary/Staff Report”. 2001. 

ARB, 2003. Air Resources Board. “Ambient Monitoring for Hexavalent Chromium and 

Metals in Barrio Logan: May 2001 through May 2002”. 2003. 

ARB, 2004a. Air Resources Board. “Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking – Airborne Toxic Control Measure to Reduce Emissions of 

Hexavalent Chromium and Nickel from Thermal Spraying”. 2004. 

ARB, 2004. Air Resources Board. “Barrio Logan Report: A Compilation of Air Quality 

Studies in Barrio Logan”. 2004. 

ARB, 2005a. Air Resources Board. “Proposed Identification of Environmental Tobacco 

Smoke as a Toxic Air Contaminant: Executive Summary”. 2005. 

ARB, 2006a. Air Resources Board. “The California Almanac of Emissions And Air 

Quality”. 2006 Edition. 
Chapter II Page 23 

ARB, 2006b. Air Resources Board. Annual Statewide Toxics Summary-Hexavalent 

Chromium. 2006. (http://www.arb.ca.gov/adam/toxics/statepages/cr6state.html) 

ATSDR, 2000. Agency for Toxic Substances and Disease Registry. “Toxicological 

Profile for Chromium”. 2000. 

SCAQMD, 2003a. South Coast Air Quality Management District. “Draft Staff Report -

Proposed Amended Rule 1469-- Hexavalent Chromium Emissions from Chrome Plating 

and Chromic Acid Anodizing Operations and Proposed Rule 1426- Emissions from Metal 

Finishing Operations.” 2003 

U.S. EPA, 1996. U.S. Environmental Protection Agency. “Emission Factor 

Documentation for AP-42 Section 12.20 – Electroplating – Final Report”. 1996. 

U.S. EPA, 2000. U.S. Environmental Protection Agency, Office of Air Quality Planning 

and Standards, Research Triangle Park, NC. 453/R-99-007: “National Air Toxics 

Program: The Integrated Urban Strategy, Report to Congress”. 2000. 
Chapter III Page 24 

III. Public Outreach and Data Collection 

Public participation is a key ingredient of ARB's regulatory process. Reliable data are 

also necessary to provide a sound basis for regulatory action. This Chapter summarizes 

our efforts to inform and involve all stakeholders in the regulatory process. We also 

summarize our data collection efforts. 

A. Public Involvement 

The full benefits of public participation are realized when all stakeholders are involved and 

informed, particularly those directly affected by a regulation. In addition, public outreach 

to low-income and ethnically diverse communities is an important tool for fulfilling ARB’s 

goal to provide equal environmental protection to all Californians. Thus, throughout the 

development of the proposed amendments to the ATCM, staff worked with the affected 

industry and public organizations to offer opportunities to: 1) become informed about the 

proposed changes to the ATCM and the public process; 2) provide pertinent information 

for ARB staff consideration; and 3) discuss comments and concerns. 

Staff has used Internet web page http://www.arb.ca.gov/toxics/chrome/chrome.htm and 

electronic and mail-out notices to alert and invite organizations and individuals to 

workgroup meetings, public workshops, and to the public hearing at which these 

proposed changes to the ATCM will be considered. In addition, outreach efforts have 

included personal contacts via telephone, electronic mail, U.S. mail, surveys, facility visits, 

and meetings. The following stakeholders have been involved in the process: 

• Chromium plating and chromic acid anodizing facility owners and operators; 

• Metal finishing industry associations; 

• Chemical suppliers; 

• Control equipment manufacturers; 

• Representatives from federal agencies, including the U.S. EPA and OSHA; 

• Representatives from State agencies, including the Department of Toxic 

Substance Control (DTSC), the Water Resources Control Board, and the 

Business, Transportation, and Housing Agency; 

• Representatives from California Air Pollution Control and Air Quality Management 

Districts; 

• Environmental and community groups; and 

• Representatives from pollution prevention and public health advocate 

organizations. 

Stakeholders were initially made aware of ARB’s intention to evaluate the current ATCM 

in January 2002 when stakeholder workgroups meetings were held in Diamond Bar, 

Fresno, and San Francisco, California. Over the course of the evaluation of the industry, 

the emissions testing program, and regulatory concept development, stakeholders were 

given the opportunity to participate and comment. A summary of outreach activities is 

shown below: 
Chapter III Page 25 

• Forming a District Workgroup and conducting meetings and conference calls; 

• Forming a Stakeholder Workgroup and conducting meetings throughout the state; 

• Creating the Hexavalent Chromium mailing list, activity website and maintaining a 

List-Serve to update interested parties; 

• Conducting site visits in various districts to familiarize ARB staff with chromium 

plating and chromic acid anodizing processes and to select facilities for the 

emissions testing program; 

• Preparing and disseminating a fact sheet on chromium plating and chromic acid 

anodizing operations for community outreach meetings; 

• Participating in the SCAQMD negotiated rulemaking process; 

• Conducting surveys on industry throughput levels and economics by mail, facsimile 

and telephone; 

• Conducting a survey of chemical fume suppressant manufacturers; 

• Developing a compliance assistance compact disk; 

• Mailing workshop notices and posting workgroup materials on ARB’s website; and 

• Conducting public workshops in various locations within the State. 

Staff held numerous meetings with affected industry and the public. A chronology of 

meetings is compiled in Appendix B of this report. In addition as specified in Health and 

Safety Code 39665(c), relevant comments on the ATCM received by ARB on the 

proposed amendments to the ATCM have been included in the administrative record. 

They are listed as a reference at the end of this Chapter (ATCM comments) and are 

available from ARB staff upon request for public review and comment. 

B. Data Collection Tools 

ARB staff gathered information by conducting surveys of air districts, chromium plating 

and chromic acid anodizing operations, and chemical fume suppressant manufacturers. 

A brief summary of the types of information collected is summarized below. 

 1. Air District Survey 

Chromium plating and chromic acid anodizing operations are located in eight air districts. 

Because air districts implement the ATCM, ARB staff worked with them throughout the 

evaluation process to gather information on chromium plating and chromic acid anodizing 

facilities. To characterize the industry, ARB staff requested permit information, ongoing 

compliance reports, source test results, and available risk assessment information for 

active chromium plating and chromic acid anodizing operations. These data were used to 

form an initial mailing list and preliminary emission estimates. To gather more 

information, ARB staff conducted facility surveys and a receptor survey. 
Chapter III Page 26 

2. Chromium Plating and Chromic Acid Anodizing Facility Survey

 

The first step in evaluating the existing ATCM was to characterize the facilities in 

California. A letter dated April 12, 2004, was sent to each facility informing them of ARB's 

effort to re-evaluate the Chromium Plating ATCM and included a brief questionnaire 

related to calendar year 2003. The list of questions included type of operation, annual 

throughput in ampere-hours, type of in-tank and add-on controls, manual or hoist lines, 

grinding and polishing operations, and questions on storage of chemicals. To collect the 

information on the questionnaire, ARB staff contacted all facilities by telephone. The 

results of the survey were used to characterize the industry (see Chapter IV) and assess 

technological feasibility (see Chapter VI). The survey is included as Appendix C to this 

report. 

3. Chemical Fume Suppressant Manufacturers Survey

The ARB staff also conducted a survey of chemical fume suppressant manufacturers to 

gather information on chemical fume suppressants and recommendations on optimum 

tank conditions for efficient plating. The survey requested information on fume 

suppressant formulations, the primary mechanism of reducing hexavalent chromium 

emissions, and recommended surface tension. We also collected information on 

recommended tank contaminant levels to determine when bath clean-up was 

recommended, such that decorative chromium plating baths would operate most 

efficiently. The survey information is summarized in Chapter IV. The survey is included 

as Appendix D to this report. 

 

4. Economic Questionnaire 

The ARB is required by law to assess the economic impact of regulations on the affected 

industry. To assist with this requirement, ARB staff contacted the facilities by mail in 

February 2005. The letter included a brief economic questionnaire to collect financial 

information for calendar year 2003. Businesses were then contacted by telephone to 

complete the questionnaire. These data are summarized in Chapter IV. The 

questionnaire is included as Appendix E to this report. 
Chapter III Page 27 

REFERENCES 

ATCM Comments. Comment letters received by ARB on the proposed amendments to 

the Chromium Plating ATCM. 
Chapter IV Page 28 

IV. Chromium Plating and Chromic Acid Anodizing 

Operations 

ARB has regulated chromium plating and chromic acid anodizing facilities since 1988. In 

this Chapter, we provide a brief summary describing the processes. A detailed review of 

the source category can be found in the original staff report (ARB, 1988b). As part of our 

evaluation of the effectiveness of the existing ATCM, staff conducted two facility surveys. 

This Chapter also summarizes the results of these surveys by providing an overview of 

chromium plating and chromic acid anodizing facilities in California in 2003. One goal of 

the proposed amendments is to further reduce hexavalent chromium emissions and 

exposure; therefore, this Chapter primarily describes information on hexavalent chromium 

plating and chromic acid anodizing operations. 

A. Overview 

Electroplating is a chemical or electrochemical process of surface treatment. A metallic 

layer is deposited onto a base material. In the chromium plating process, an electrical 

charge is applied to a plating bath containing an electrolytic salt (chromium anhydride) 

solution. The electrical charge causes the chromium metal in the bath to fall out of 

solution and deposit onto various objects (usually metallic) placed into the plating bath. In 

an anodizing process, an oxide film is formed on the surface of the part. 

The hexavalent chromium plating process is only about 20 percent efficient. This 

inefficiency leads to excess generation of hydrogen and oxygen bubbles as electrical 

current is applied to the plating bath. The bubbles rise through the tank and burst at the 

surface, leading to emissions of hexavalent chromium. Facilities using trivalent chromium 

baths emit trivalent chromium in the process. Once emitted from the facility, hexavalent 

chromium can be inhaled and entrained in the lungs. In a similar manner hexavalent 

chromium mist is generated during chromic acid anodizing. Thus, hexavalent chromium 

emissions have the potential to adversely impact public health on a statewide basis, as 

well as at the local community level. A schematic diagram of a plating tank is shown in 

Figure IV-1. 
Chapter IV Page 29 

 Figure IV-1. Main Components of an Electroplating Tank 

From OHCOW, 1997 

As shown in Figure IV-1, the part to be plated becomes the cathode in the circuit. In 

chromic acid anodizing, the part to be oxidized serves as the anode in the circuit. 

B. Types of Chromium Operations 

As mentioned above, facilities use either trivalent or hexavalent chromium baths. 

However, the trivalent chromium plating process is only available for decorative chromium 

plating applications. Facilities using hexavalent chromium baths can be divided into three 

types. These include hard chromium (or functional chromium) plating operations, 

decorative chromium plating operations, and chromic acid anodizing operations. 

Decorative plating includes black chromium plating which is selected both for its 

functional and decorative properties. It has a dull dark gray, or black finish when 

polished. It has numerous applications and can be used in military, aerospace, 

automotive or other applications. It is a semi hard, non-reflective, abrasion resistant, heat 

and corrosion resistant coating. 

The same hexavalent chromium bath chemistry can be used for both hard and decorative 

chromium plating. Table IV-1 provides a summary of the three processes. 

Source: Burgess WA 

Recognitions of Health 

Hazards in Industry – A 

Review of Materials & 

Processes, 2nd edition John 

Wiley & Sons Inc., 1995 

(CATHODE)
Chapter IV Page 30 

Table IV-1. Description of Hexavalent Chromium Operations 

HARD CHROMIUM 

PLATING 

DECORATIVE 

CHROMIUM 

PLATING 

CHROMIC ACID 

ANODIZING 

Type of layer Thick layer (2.5 μm – 

760 μm) 

Thin layer 

0.003 μm-2.5 μm 

Electrochemical 

conversion 

Properties 

provided 

Corrosion protection, 

wear resistance, 

lubricity and oil 

retention among 

other properties 

A decorative and 

protective finish 

Corrosion and 

abrasion resistant 

surface by forming 

an oxide coating 

Type of parts Engine parts, 

industrial machinery, 

and tools 

Bath fixtures, faucets, 

automotive bumpers 

and wheels, furniture 

components, 

motorcycle parts 

Architectural 

applications, landing 

gears, giftware and 

novelties, 

automotive trim and 

bumpers 

Plating duration Hours or days Seconds or minutes <1 – 5 minutes 

Substrate Typically plated on 

steel 

Typically plated on 

Nickel 

Aluminum 

The most familiar type of chromium plating is decorative chromium plating which provides 

a bright, and shiny finish on objects such as faucets and wheels. Generally, the base 

material has been nickel-plated prior to plating the chromium. 

C. Data Resources 

To characterize the industry, ARB staff contacted all air districts with active chromium 

plating and chromic acid anodizing facilities. These operations are under permits to 

operate issued by air districts and must comply with applicable district rules or the 

Chromium Plating ATCM. Together with the air districts and utilizing other data sources, 

a list of 355 potential operations was developed. A letter was sent to these 355 facilities 

informing them of ARB’s intent to review the ATCM, and requesting them to provide basic 

information about their business. Each facility was contacted by telephone to complete 

the questionnaire. From this survey, 222 active hexavalent chromium plating and chromic 

acid anodizing facilities and ten trivalent chromium plating operations were identified. Of 

the ten trivalent chromium operations, six facilities only plate using the trivalent chromium 

process, while the other four operations are part of a business that also conducts 

hexavalent chromium plating. ARB staff also conducted an economic survey to gather 

employee and economic information. Data on proximity of plating shops to receptors was 

also gathered with the assistance of the air districts. A summary of the data collected 

from our surveys is provided in the following sections. 
Chapter IV Page 31 

D. Industry Characterization 

The following sections provide information collected from our calendar year 2003 industry 

survey. Note that a distinction is made between number of facilities and number of 

operations. This is necessary because some facilities perform multiple operations. For 

example, one facility may conduct chromic acid anodizing as well as hard chromium 

plating. 

1. Location and Number of Plating and Anodizing Facilities

ARB staff determined that in 2003 there were 228 combined trivalent and hexavalent 

chromium plating and chromic acid anodizing facilities in California. Several of these 

facilities perform multiple operations using hexavalent chromium (230 operations) and 

trivalent chromium (10 operations). Four hexavalent chromium plating facilities also 

conduct trivalent chromium plating. There are six facilities that only conduct trivalent 

chromium plating. Most of this Chapter will focus on the 222 hexavalent chromium plating 

and chromic acid anodizing facilities. The facility list was verified by air districts. 

Therefore, we believe that the industry is fully represented. Information collected 

included: facility location; type of operation; total throughput; add-on air pollution control 

equipment; in-tank controls; source test information; type of plating line; and grinding and 

polishing activity information. In the following graphs, note the distinction between facility 

and operation as we characterize the industry. 

Out of 240 operations, the majority are in located in the SCAQMD. Figure IV-2 below 

depicts the plating and anodizing operations by air district. Other air districts include 

Shasta, Sacramento, Ventura, and Feather River. 

 Figure IV-2. Distribution of Chromium Operations by District (2003) 

BAAQMD

9%

SCAQMD

75%

SJVAPCD

7%

OTHER

9%
Chapter IV Page 32 

Out of 240 operations, 230 are hexavalent chromium plating or anodizing operations and 

ten are trivalent chromium plating operations. Table IV-2 below summarizes all active 

facilities by operation type. Note that there were 228 active chromium plating and 

chromic acid anodizing facilities in California in 2003 and twelve of them perform multiple 

operations. 

Table IV-2. Number of Operations by Plating Type 

Hexavalent Chromium Baths 

Hard (Functional) Chromium Plating 58

Decorative Chromium Plating 127

Chromic Acid Anodizing 45

Trivalent Chromium Baths 

Trivalent Chromium Plating 10

TOTAL 240

Figure IV-3 below shows that of the 222 active hexavalent chromium facilities, 

55 percent of them perform decorative chromium plating, 25 percent perform hard 

(functional) chromium plating, and 20 percent conduct chromic acid anodizing. 

Figure IV-3. Distribution of Hexavalent Chromium Operations by Type (2003)

Emissions of hexavalent chromium from plating and anodizing operations depend on total 

throughput in ampere-hours. An ampere-hour is a unit of amperes integrated over time. It 

is an important variable because it determines the amount of hexavalent chromium 

emissions from a facility. The ampere-hours are multiplied by the emission rate 

(milligrams/ampere-hour) to calculate emissions. This is discussed later in 

Chapter V on emissions. Table IV-3 provides a summary of throughput ranges and 

averages by plating type. Data were not available for two operations, therefore, the 

numbers in Tables IV-2 and IV-3 differ slightly. 

Hard

25%

Anodizing

20%

Decorative

55%
Chapter IV Page 33 

Table IV-3. Hexavalent Chromium Plating Type and Ampere-hours (2003) 

Hard Decorative Anodizing 

Number of operations 

57 126 45 

Range of Amperehours 

1,200 – 

79,000,000 

120 – 

82,900,000 

260 – 2,000,000 

Average (Mean) Amperehours 12,500 1,700,000 150,000 

Median Ampere-hours 2,900,000 95,000 43,000 

*Unknown throughput information for 2 plating or anodizing operations 

Although the ranges appear similar for hard and decorative plating, generally amperehours from hard chromium plating operations are much higher than those from decorative 

chromium plating. This can be seen by comparing the mean and median ampere-hours 

shown in Table IV-3. The higher throughput levels, in ampere-hours, that are shown for 

hard chromium plating are related to the length of time required to build the thick 

chromium layer typical of hard chromium plating. 

In terms of throughput, many chromium plating and chromic acid anodizing facilities are 

small operations. Figure IV-4 shows the level of throughput, in ampere-hours for the 

various operations. 

Figure IV-4. Throughput (in Ampere-hours) for Chromium Plating and Chromic 

 Acid Anodizing Facilities in California (2003) 

48

60

45

34

15 18

0

10

20

30

40

50

60

70

Number of Facilities

< 20,000

20,000 - 200,000

200,000 - 1 Million

1 - 5 Million

5 - 15 Million

>15 Million
Chapter IV Page 34 

As shown in Figure IV-4, 48 (about 20 percent) facilities have annual throughput of 

20,000 annual ampere-hours or less. Sixty facilities (27 percent) have throughput of 

between 20,000 to 200,000 annual ampere-hours. Over 50 percent of facilities have 

annual ampere-hours over 200,000. 

2. Control Equipment

All chromium plating and chromic acid anodizing facilities already use a variety of controls 

to comply with the existing ATCM. Emissions control can be achieved through using 

add-on air pollution controls, such as filter systems, or in-tank controls, primarily chemical 

fume suppressants that reduce surface tension. The staff collected information on the 

types of emission controls in use based on visits to many plating and anodizing 

operations, and through the survey. The following section provides information on 

controls currently being used by the chromium plating and chromic acid anodizing 

industry. A description of these control types is provided in Chapter VI. 

To comply with the existing ATCM, hard chromium plating facilities must use add-on air 

pollution control devices to meet emission limitations expressed in milligrams/amperehour (an alternative to meet a surface tension limit is provided for hard chromium plating 

facilities with less than 500,000 ampere-hours). Decorative plating and chromic acid 

anodizing facilities have the option of complying with an emission limit expressed in 

milligrams/dry standard cubic meter of air (mg/dscm) or meeting a surface tension 

requirement using a chemical fume suppressant with a wetting agent. Most have chosen 

the latter means of complying. Many facilities use a combination of controls to reduce 

emissions. Figure IV-5 shows distribution of current control options in use at the 

hexavalent chromium facilities in California. 

Figure IV-5. Distribution of Emission Controls by Type of Chromium Operation 

 

*Note no information about 2 operations that have shut down since 2003

10 4 6

38

34

21

9

88

18

0

10

20

30

40

50

60

70

80

90

100

Number of Operations

A dd-On Only A dd-On + In tank

C o ntro ls

In tank co ntro ls Only

Hard Decorative Anodizing
Chapter IV Page 35 

As shown in Figure IV-5, in 2003, there are 113 operations controlling hexavalent 

chromium emissions with add-on air pollution control devices. Of facilities with add-on air 

pollution controls, 69 operations (14 chromic acid anodizing, 26 decorative chromium, and 

29 hard chromium plating facilities), or 61 percent, had HEPA filters as their final control. 

Our survey also gathered source test emission rate information for facilities. Out of 

113 operations with add-on air pollution control device(s), source test information was 

available for 71 (63 percent) of the operations. 

Figure IV-5 also shows that the majority of operations used chemical fume suppressants 

as the sole source of emission control. As shown, 88 operations, or almost 70 percent of 

decorative chromium plating operations used chemical fume suppressants to control 

hexavalent chromium emissions. Note also that there are several hard chromium plating 

facilities using chemical fume suppressants. These are operations with throughput below 

500,000 ampere-hours per year. 

3. Housekeeping

Because of information gleaned from our Barrio Logan study, we also gathered 

information on grinding and polishing operations within facilities, and whether the plating 

line was automatic or manual. We are interested in this information because operations 

with grinding and polishing activities generate dust, which could act as a sink for 

hexavalent chromium mist being emitted from the plating or anodizing tank. Once 

disturbed by activities of the workers or ventilation within the operation, the dust can be 

re-entrained leading to fugitive emissions of hexavalent chromium. 

Through the survey, we found 145 facilities that performed grinding polishing or buffing 

on site and 72 that did not. No information was available for five facilities. 

The manner in which parts are processed, particularly for decorative plating, also could 

lead to hexavalent chromium emissions as droplets of liquid from the plating tank may fall 

to the floor surrounding the tank. Again, this could lead to dust and fugitive emissions of 

hexavalent chromium. Automatic lines generally have tanks set up in a row but manual 

lines may not. We found that were 186 facilities with manual lines, 30 with automatic 

lines, and 3 facilities that had both manual and automatic lines. No information was 

available for 4 facilities. 

 4. Sensitive Receptor Distances 

As we found in Barrio Logan, the impacts of hexavalent chromium emissions are highly 

localized. While ambient hexavalent chromium emissions may be low, emissions of 

hexavalent chromium from plating and anodizing could pose significant exposures to 

receptors living near the source. Therefore, to assess potential adverse impacts to near 

source receptors, with assistance from the air districts, ARB staff determined the 

distances to the nearest sensitive receptors for all facilities. Figure IV-6 provides 

distances, in meters, from the source to the nearest sensitive receptor for all hexavalent 

chromium facilities by type of operation. The receptors include: any residence including 

private homes, condominiums, apartments, and living quarters; education resources such 
Chapter IV Page 36 

as preschools and kindergarten through grade twelve (K-12) schools; daycare centers; 

and health care facilities such as hospitals, retirement and nursing homes, long term care 

hospitals, hospices, prisons, and dormitories or similar live-in housing. 

Figure IV-6. Distance (in Meters) Between Hexavalent Chromium Facilities and the 

 Nearest Sensitive Receptor 

43

26 27

126

0

20

40

60

80

100

120

140

Number of Facilities

<25 >25 <50 >50 <100 >100

Distance to Receptor (meters)

As shown in Figure IV-6, and as stated previously, 96 hexavalent chromium facilities are 

located within 100 meters of a sensitive receptor. This represents 43 percent of the 

facilities. Of these, 76 are decorative chromium plating and chromic acid anodizing 

facilities that generally control emissions with chemical fume suppressants. Figure IV-6 

also shows that 43 of these facilities are located within 25 meters of a sensitive receptor.

5. Economic Survey

To characterize the industry financially, ARB staff contacted active facilities in 

February 2005 to obtain economic information. These data for the 2003 calendar year 

are summarized here and will be used to determine the economic impacts of the 

proposed amendments on chromium plating and chromic acid anodizing facilities. The 

financial information obtained is shown in Figure IV-7. 
Chapter IV Page 37 

Figure IV-7. Gross Annual Revenue for Hexavalent Chromium Plating and Anodizing 

 Facilities (2003) 

As shown in Figure IV-7, out of 222 hexavalent chromium facilities, we found that one 

third had gross annual revenue of less than $1,000,000, while another third had revenues 

between $1,000,000 to $5,000,000. About 20 percent have annual revenue over 

$5,000,000. No information was received from 14 percent of the facilities. 

Table IV-4 provides data on the number of people employed by various plating and 

anodizing businesses. 

Table IV-4. Number of Employees at Chromium Plating and Chromic Acid 

Anodizing Facilities 

Employee Number Range Number of 

Facilities 

1 – 10 60 

11 – 25 46 

26 – 100 61 

>101 24 

No information 31 

As shown in Table IV-4, 25 percent (60 facilities) employ ten or fewer people. Seventyfive percent of facilities have less than 100 employees. 

< $1,000,000 

33%

No Information

14%

$1,000,000 - 

$5,000,000 

34%

$5,000,000 - 

$10,000,000 

7%

> $10,000,000 

12%
Chapter IV Page 38 

REFERENCES 

 

ARB, 1988b. Air Resources Board. “Staff Report; Initial Statement of Reasons for 

Proposed Rulemaking – Proposed Airborne Toxic Control Measure for Emissions of 

Hexavalent Chromium from Chrome Plating and Chromic Acid Anodizing Operations”. 

1988. 

OHCOW, 1997. Occupational Health Clinics for Ontario Workers Inc. “Electroplating – A 

Focus on Chrome Plating”. 1997
Chapter V Page 39 

V. Emissions 

This Chapter presents a summary of our decorative chromium plating emissions testing 

program to investigate and, if needed, improve the emission factor for chemical fume 

suppressant controlled decorative plating facilities. Based on the emission factor 

developed through the testing program, this Chapter also includes 2003 estimated 

statewide emissions of hexavalent chromium from chromium plating and chromic acid 

anodizing facilities in California. As background, information on existing hexavalent 

chromium emission factors is also included. 

A. Overview 

One goal of characterizing the industry and estimating hexavalent chromium emissions 

was to assess the potential for significant near-source residual cancer risk resulting from 

chromium plating and chromic acid anodizing. The remaining risk, if any, would be from 

facilities already complying with the Chromium Plating ATCM and air districts rules. 

During our evaluation, it became clear that a better understanding of emissions occurring 

from decorative chromium plating was necessary. To comply with the ATCM, most 

decorative chromium plating facilities have used chemical fume suppressants to reduce 

the bath surface tension. Reducing the surface tension reduces misting and, therefore, 

hexavalent chromium emissions. However, the overall effectiveness of chemical fume 

suppressants to reduce emissions was not well quantified. Therefore, ARB staff 

undertook an emissions testing program to quantify hexavalent chromium emissions from 

decorative chromium plating facilities using chemical fume suppressants. 

B. Emission Factor Background 

ARB staff, in 1988, established for hexavalent chromium plating and chromic acid 

anodizing operations uncontrolled and controlled hexavalent chromium emission factors 

(ARB, 1988b). These factors were based on source tests available at the time. For hard 

chromium plating and chromic acid anodizing facilities, an uncontrolled emission factor of 

5.2 milligrams/ampere-hour was established. Based on available data, an uncontrolled 

emission factor of 0.5 milligrams/ampere-hour was established for decorative chromium 

plating facilities. ‘Controlled’ emission factors were then developed based on efficiencies 

reported for various control methods. For example, at the time, chemical fume 

suppressants were thought to be 95 percent effective. Therefore, the controlled 

hexavalent chromium emission factor was believed to be 0.025 milligrams/ampere-hour, 

based on uncontrolled decorative chromium emissions of 0.5 milligrams/ampere-hour. 

Likewise, an emission factor of 0.006 milligrams/ampere-hour for hard chromium plating 

facilities was based on 99.8 percent control from an uncontrolled hard chromium plating 

emission factor of 5.2 milligrams/ampere-hour. 

Controlled emissions for hard chromium plating operations have since been measured 

directly through source testing emissions downstream of add-on air pollution control 

devices. However, quantifying controlled emissions from decorative plating operations 

has been more difficult because most facilities do not have add-on air pollution control 

devices. To better assess residual health risk from decorative chromium plating facilities, 
Chapter V Page 40 

improved information on emissions from tanks controlled with chemical fume 

suppressants was necessary. To that end, ARB undertook an emissions testing program. 

In other developments, the SCAQMD also tested effectiveness of chemical fume 

suppressants to control hexavalent chromium emissions. (SCAQMD, 2004) From their 

testing, a list of chemical fume suppressant products was developed that under specified 

conditions, would result in emissions of no more than 0.01 milligrams/ampere-hour. The 

list of SCAQMD certified chemical fume suppressants can be found on the air district 

website at: http://www.aqmd.gov/prdas/chrome%20plating/chromeplating.htm 

A summary of controlled and uncontrolled emission factors for decorative plating tanks 

that existed prior to our testing program is provided in Table V-1 below. 

Table V-1. Decorative Chromium Plating Emission Factors in Existence Prior to ARB 

 Testing Program (milligrams/ampere-hour) 

ARB 

(1988) 

U.S. EPA 

(1996) 

SCAQMD 

(2003) 

Uncontrolled 0.5 2.14 4.4

Controlled with foam or foam plus 

scrubber 

0.025 -- --

Controlled with chemical fume 

suppressants 

0.025 0.008 --

Controlled with certified chemical fume 

suppressants 

-- -- 0.01

Controlled with HEPA filter 0.0015

In reviewing the data in Table V-1, it becomes clear that residual cancer risk would vary 

widely based on the emission factor chosen. 

C. Emissions Testing Program

1. Overview

During our Barrio Logan study unexpectedly high concentrations of hexavalent chromium 

were measured outside a decorative chromium plating facility in San Diego (refer to 

Chapter II). These concentrations were higher than would have been predicted based on 

ARB’s decorative chromium plating emission factor. In light of these findings, we 

conducted an emissions testing program at decorative chromium plating businesses to 

gather emissions information. The testing was conducted in two phases in consultation 

with the chromium plating industry and the air districts. Each test consists of three test 

runs. These individual runs are averaged to determine an emission rate. A summary of 
Chapter V Page 41 

both phases and testing result summary tables are provided in the sections below. 

Appendix F contains further data on each test conducted. 

2. Phase I

During Phase I of the testing program, ARB staff conducted four source tests at three 

decorative chromium plating facilities. These facilities had forced ventilation systems and 

were using a variety of controls which included chemical fume suppressants. All of these 

tests measured emissions after in-tank controls (chemical fume suppressants) alone. 

These in-tank control test results ranged from 0.0017 to 0.810 milligrams/ampere-hour, 

with an average of 0.21 milligrams/ampere-hour. After evaluating these data, staff 

determined that the presence of forced ventilation systems may have led to higher 

emission rates than would be representative of the overall decorative chromium plating 

industry. Table V-2 presents results of the Phase 1 testing. 

Table V-2. Average Hexavalent Chromium Emission Rates and Selected Testing 

 Parameters for Phase 1 

Test Number 1 2* 2* 3 4 

Date 1/2003 1/2003 1/2003 3/2003 4/2003 

Mean Hexavalent Chromium 

Emission Rate 

(milligrams/ampere-hour) 

0.19 0.28 0.003 0.003 0.159 

SurfaceTension* 

(dynes/centimeter) 35.5 38.5 38.5 33.2 32.7 

Chemical Fume Suppressant 

CR 

1700® 

CR 

1700®

CR 

1700® 

Fumetrol 

140® Dis Mist NP®

Other Controls None None 

Composite 

Mesh Pad Polyballs None 

Chromic Acid Concentration 

(ounce/gallon) 33.8 33.2 33.2 44.7 21.4 

* Same test, emissions collected before and after the composite mesh pad. 

These data were not used to develop an emission factor. However, we did find that, even 

though emissions off the tank varied widely, emissions after an add-on air pollution 

control device were consistently low. In one test we measured hexavalent chromium 

emissions before and after an add-on air pollution control device, a composite mesh pad 

system. The samples collected before the composite mesh pad system would be 

representative of a tank controlled with chemical fume suppressants. In this test, 

although the emission rate results collected before the composite mesh pad system 

varied for each of three test runs (0.0017 to 0.810 milligrams/ampere-hour), the emission 

rates measured after the composite mesh pad were consistent. Emission results ranged 

from 0.002 to 0.003 milligrams ampere-hour with an average of 0.003 milligrams/amperehour. These results provide evidence that add-on air pollution control devices provide a 
Chapter V Page 42 

consistent level of control regardless of operating parameters. In another test, use of 

polyballs and chemical fume suppressant yielded an emission rate of 

0.003 milligrams/ampere-hour. This test result indicates that polyballs combined with intank controls provides emission reduction benefits over that achieved with chemical fume 

suppressants alone. 

From these tests, we also evaluated differences in surface tension readings based on two 

types of instruments: a stalagmometer and a tensiometer. There was a difference 

observed between measurements with the two instruments. While all stalagmometer 

surface tension readings were higher than the tensiometer readings, no uniform 

difference was seen (i.e. they did not consistently vary by the same amount of 

dynes/centimeter). In developing the proposed amendments to the Chromium Plating 

NESHAP, U.S. EPA determined that measurements between the two instruments varied 

consistently by ten dynes/centimeter. Our testing did not confirm this. 

We also learned that the emission rates from decorative chromium plating tanks were 

similar to those of hard chromium plating facilities with similar controls. We believe this 

indicates that uncontrolled emissions from decorative plating facilities were 

underestimated during the development of the original ATCM. This finding supports the 

proposal to have similar emission limits for all plating types. 

3. Phase II

During Phase II of the testing program, ARB staff measured hexavalent chromium 

emissions at facilities with open tanks (i.e., they do not have forced ventilation systems). 

These facilities all reduced hexavalent chromium emissions using chemical fume 

suppressants as the sole control source. These facilities are more representative of the 

decorative plating industry. Seven source tests were conducted at three facilities. To 

facilitate testing, ARB staff designed a temporary hood to capture emissions. The 

temporary hood set-up is shown in Figure V-1. 
Chapter V Page 43 

Figure V-1. Temporary ‘Hood’ for Capturing Hexavalent Chromium Emissions at 

Decorative Chromium Plating Facilities 

The results of the first six tests were used to assess existing hexavalent chromium 

emissions from various decorative chromium plating tanks without forced ventilation. 

These tanks were all controlled with various chemical fume suppressants. The mean 

emission rate from these tests is representative of emissions existing prior to 

implementation of Rule 1469 in the SCAQMD. Table V-3 provides results for each of the 

first six tests. 

TEMPORARY

HOOD 

DUCT
Chapter V Page 44 

Table V-3. Average Hexavalent Chromium Emission Rates and Selected Testing 

Parameters for Phase II 

Test Number 1 2 3 4 5 6 

Date 1/2004 2/2004 5/2004 10/2004 5/2005 6/2005 

Mean Hexavalent Chromium 

Emission Rate 

(milligrams/ampere-hour) 

0.009 0.004 0.050 0.050 0.052 0.065 

SurfaceTension* 

(dynes/centimeter) 39.9 29.5 36.8 42 30.1 31.5 

Chemical Fume Suppressant 

Protab 

1000®

Clepo 

Mist® 

Protab 

1000®

Chrome 

Foam® 

Chrome 

Foam® 

Chrome 

Foam® 

Chromic Acid Concentration 

(ounce/gallon) 36 34.7 33.4 30.2 25 28.2 

* Surface tension was determined using a stalagmometer 

For consistency, several variables remained as constant as practicable for the six tests 

shown in Table V-3. [The seventh test was done to verify the results of the SCAQMD 

fume suppressant certification program. The results of this test will be discussed 

separately.] The plating tanks were of similar size, the ampere-hours per test were 

consistent, and the same number and types of parts were plated each time. More details 

on each of these six tests are included in Appendix F. In addition to evaluating the 

effectiveness of different chemical fume suppressants to control hexavalent chromium 

emissions, we also monitored several other parameters to determine the effect, if any, on 

hexavalent chromium emissions. A brief description of our findings is provided below. 

a. Hexavalent Chromium Emission Factor for Chemical Fume Suppressant 

Controlled Plating Tanks Derived from the Emissions Testing Program

Using the results from the six tests shown in Table V-3, a hexavalent chromium emission 

factor was developed to quantify the emissions from chromium plating and chromic acid 

anodizing operations using chemical fume suppressants as the sole source of control. 

These data are representative of ‘real world’ conditions. The emission rates from six tests 

ranged from 0.004 to 0.065 milligrams/ampere-hour, with an average of 

0.04 milligrams/ampere-hour. For establishing the 2003 statewide hexavalent chromium 

emissions, this average emission rate, 0.04 milligrams/ampere-hour, was used. 

b. Assessing Chemical Fume Suppressants to be Used for Compliance with 

 the ATCM

Concurrent with our testing program, the SCAQMD tested chemical fume suppressants 

under controlled conditions. The purpose of this testing was to determine parameters that 

yielded optimum emission reductions. The SCAQMD demonstrated that hexavalent 

emissions can be further reduced if certain chemical fume suppressants are used. In 

fact, the SCAQMD demonstrated that several chemical fume suppressants could reduce 

emissions of hexavalent chromium to no more than 0.01 milligrams/ampere-hour 
Chapter V Page 45 

(SCAQMD, 2004a). The surface tension at which this emission rate is achieved is at 

lower surface tension than currently required in the ATCM. 

Our first six tests were used to estimate emissions based on how facilities normally 

operate using chemical fume suppressants. Test seven was designed to verify the 

SCAQMD results. The seventh test was conducted using the chemical fume 

suppressant, Fumetrol 140®. This chemical fume suppressant was certified by the 

SCAQMD to reduce hexavalent chromium emissions to no more than 

0.01 milligrams/ampere-hour when surface tension is maintained below 

40 dynes/centimeter. 

The results of the this test yielded an average emission rate of 0.009 milligrams/amperehour. This emission rate was achieved when surface tension was maintained at 

35 dynes/centimeter, just below the level of SCAQMD certification. ARB was able to 

confirm results of the SCAQMD fume suppressant certification program. Based on this 

test result, as well as an evaluation of the SCAQMD source test data from their chemical 

fume suppressant certification program, ARB staff determined the chemical fume 

suppressants that would reduce emissions of hexavalent chromium to no more than 

0.01 milligrams/ampere-hour at specified surface tensions. (SCAQMD, 2004a) Table V-4 

lists these chemical fume suppressants with the surface tension at which the emission 

rate of 0.01 milligrams/ampere-hour is achievable. 

Table V-4. Chemical Fume Suppressants Approved for Use at Specified Surface 

 Tensions 

Chemical Fume 

Suppressant and 

Manufacturer 

Stalagmometer Measured 

Surface Tension (dynes/cm) 

Tensiometer Measured 

Surface Tension 

(dynes/cm) 

Benchbrite CR 1800® 

Benchmark Products <40 <35 

Clepo Chrome® 

MacDermid <40 <35 

Fumetrol 140® 

Atotech U.S.A. <40 <35 

 

Note that Table V-4 does not list all chemical fume suppressants certified by the 

SCAQMD. The chemical fume suppressants that employ a foaming mechanism for 

reducing emissions are not included on this list. This foaming component is critical to the 

effectiveness of the chemical fume suppressant. Most of the chromium plating facilities 

that will use these chemical fume suppressants as sole source of control are decorative 

chromium plating facilities. Many of these facilities do not operate in a manner that would 

allow the foam blanket to form and be maintained on the surface of the plating bath. In 

instances when the foam blanket is not maintained, emissions are likely higher than 

0.01 milligrams/ampere-hour. 

Through the emissions testing program and data obtained in the SCAQMD certification 

program, staff has developed two emission factors for hexavalent chromium plating tanks 

using chemical fume suppressants. The emission factor of 0.04 milligrams/ampere-hour 
Chapter V Page 46 

is developed for all tanks using chemical fume suppressants prior to 2005. The second 

emission rate of 0.01 milligrams/ampere-hour for chemical fume suppressant controlled 

facilities is used to evaluate the SCAQMD facilities in the 2005 baseline year, while the 

emission rate of 0.04 milligrams/ampere-hour is used for facilities in other parts of the 

State. Finally, to determine the benefits of adoption of the ARB staff’s proposal, 

estimated cancer risk and emissions from facilities using chemical fume suppressants as 

the sole control will be calculated based on an emission factor of 0.01 milligrams/amperehour. 

 c. Effect of Surface Tension on Emission Rate

The requirement in the ATCM for controlling hexavalent chromium emissions with 

chemical fume suppressants specifies that surface tension is to be maintained below 

45 dynes/centimeter. Hexavalent chromium emissions are lowered as surface tension is 

reduced. Therefore, part of our testing program was to determine if reducing surface 

tension further resulted in decreased emission rates. For tests one and two, we 

evaluated the effect of reduced surface tension on emissions. The emission rates 

presented in Table V-3 are the averages of three test runs. As shown, the mean 

emission rate for test one, run at a surface tension of ~ 40 dynes/centimeter, was 

0.009 milligrams/ampere-hour, while for test two, run at a surface tension of 

~ 30 dynes/centimeter, the mean was 0.004 milligrams/ampere-hour. While the average 

emission rate for test two is lower, as determined by the statistical t-Test, at a significance 

level where α=0.05, the means, and therefore the emission rates, are not different. 

Interestingly, the emission rates for tests five and six, conducted at the same facility with 

the same chemical fume suppressant and at similar surface tensions, are higher—not 

lower—than the emission rate calculated for test four at the same facility conducted at a 

higher surface tension. We believe this indicates that other factors and practices at 

individual operations also affect the rate of hexavalent chromium emissions. 

We also evaluated emission rates with the type of chemical fume suppressant used. The 

chemical fume suppressants used in tests one through six all contain fluorinated 

surfactants as the active ingredients (further information on chemical fume suppressant 

chemistry is included in Chapter VI). Because of this, one would expect, if all other 

variables are similar, that emission rates would be similar. However, emission rates 

ranged from 0.004 to 0.065 milligrams/ampere-hour, with an average of 

0.04 milligrams/ampere-hour. Recall that ARB's historical emission factor for hexavalent 

chromium emissions from decorative chromium plating tanks is 0.025 milligrams/amperehour. 

 d. Effect of Tank Contaminants on Emission Rate

Tests four, five, and six were conducted at the same facility and were designed to 

evaluate the effect of bath contaminant levels on hexavalent chromium emissions. 

Generally, as the level of metallic contaminants builds in the plating bath, the bath 

becomes less efficient, and more current is necessary to overcome the resistance caused 

by the contaminants. Increasing the current, in turn, produces more bubbling which could 
Chapter V Page 47 

lead to an emissions increase. Table V-5 contains information obtained from our survey 

of chemical suppliers, as well as contaminant levels present in the plating bath for tests 

four, five, and six. We have also included the hexavalent chromium emission rates 

obtained from each test to allow for easy comparison. 

Table V-5. Plating Bath Contaminants, Concentration Levels Where Bath Clean-up is 

 Recommended, and Hexavalent Chromium Emission Rates 

Manufacturer 

Recommended 

Action Level* 

Test 4 Test 5 Test 6 

Metallic 

Contaminants 

(milligrams/Liter) 

5000–7000 mg/L 15,000 mg/L 60 mg/L 700 mg/L 

Trivalent 

Chromium 

0.5–1 oz/gal 0.64 oz/gal < 0.1 oz/gal 0.2 oz/gal 

Chloride 50 mg/L 130 mg/L 14 mg/L 20 mg/L 

Mean Hexavalent 

Chromium 

Emission Rate 

0.050 

mg/amp-hr 

0.052 

mg/amp-hr 

0.065 

mg/amp-hr 

* Average from 5 suppliers of chemicals to the plating industry. 

The data in Table V-5 summarize information on common contaminants. The largest 

concentrations of metallic contaminants are typically nickel, copper, and lead. Trivalent 

chromium and chloride are also common contaminants that reduce bath efficiency. Note 

that despite heavy contaminant levels in test four the emission rate was lower than the 

emission rates in the two subsequent tests. If contaminants play a role in increasing 

emissions, we would have expected test five, conducted with a freshly prepared plating 

bath with essentially no contaminants (same tank, old solution disposed of) to yield the 

lowest emission rate. While we did not find a correlation with contaminant levels and 

emission rates, we nevertheless recommend that bath contaminants be minimized by 

conducting routine maintenance. 

D. Statewide Hexavalent Chromium Emissions 

The emission factor of 0.04 milligrams/ampere-hour was used to estimate 2003 

hexavalent chromium emissions and estimated cancer risk for facilities using chemical 

fume suppressants as sole control. This would reflect emissions prior to implementation 

of Rule 1469 in the SCAQMD. 
Chapter V Page 48 

Statewide emissions of hexavalent chromium were calculated based on information from 

the 2003 survey of chromium plating and anodizing operations. To calculate emissions, 

the following equation was used: 

 

Emission Rate (milligrams/ampere-hour) X Throughput (ampere-hours/year) = 

Annual Facility Hexavalent Chromium Emissions 

Emission rates were assigned as follows: 

 Volume (fume suppressant) Tank Emission Rate: 0.04 milligrams/ampere-hour 

 Point Source Emission Rate: 

• Available emission rates from source tests 

When source data were not available, emission rates were assigned based on type of 

controls corresponding to emission rates in the current ATCM as follows: 

• HEPA or Mist Eliminator combination– 0.006 milligrams/amperehour 

• Scrubber – 0.15 milligrams/ampere-hour 

Figure V-2 shows the estimated statewide hexavalent chromium emissions in 2003. 

 Figure V-2. Statewide Hexavalent Chromium Emissions in 2003 Were 

 14.4 Pounds 

As shown in Figure V-2, statewide emissions of hexavalent chromium from chromium 

plating and chromic acid anodizing operations totaled 14.4 pounds in 2003. Facilities with 

in tank controls emitting 4.7 pounds per year, are primarily decorative plating and chromic 

acid anodizing operations. Facilities with add-on air pollution controls, emitting 

9.7 pounds per year, generally are hard chromium plating operations. However, for 

health risk reasons, a number of decorative chromium plating and chromic acid anodizing 

facilities are also controlled with add-on air pollution control devices. While this amount of 

hexavalent chromium emissions seems small on a statewide basis, the emissions are 

Facilities with add-on 

air pollution controls:

9.7 pounds 

Facilities with in-tank controls

 only: 4.7 pounds 
Chapter V Page 49 

highly localized and the cancer potency of hexavalent chromium make these emissions a 

public health concern for sensitive receptors, especially those located in close proximity to 

plating and anodizing operations. It is also important to note that the emissions of 

hexavalent chromium shown in Figure V-2 do not include fugitive emissions of hexavalent 

chromium, which we have learned can be a significant part of a facility’s overall impact. 

E. Fugitive Emissions 

In addition to hexavalent chromium emissions from the tank, chromium plating and 

chromic acid anodizing facilities also have fugitive emissions of hexavalent chromium, 

primarily dust. Dust accumulating in facilities from other operations such as grinding and 

polishing of parts prior to plating, and/or from poor housekeeping practices, provides a 

surface on which particles of hexavalent chromium from the plating operation may 

adhere. The hexavalent chromium may come directly from the plating process as mist is 

ejected from the bath. Other sources of hexavalent chromium may include droplets of 

chromic acid dripping onto other surfaces as plated parts are transferred to rinse tanks. 

This hexavalent chromium laden dust has the potential to become re-entrained due to air 

currents and activity in the plating or anodizing facilities. 

Our Barrio Logan study confirmed that emissions of hexavalent chromium from a 

decorative plating shop were not only from the actual plating process, but from hexavalent 

chromium dust which became re-entrained. A study done by SDCAPCD also measured 

significant hexavalent chromium levels in dust of chromium plating and chromic acid 

anodizing facilities. This would indicate that the residence time might be longer for 

hexavalent chromium than was originally thought. During the emissions testing program, 

ARB staff also collected indoor air samples to qualitatively measure hexavalent chromium 

emissions. These studies are discussed individually and have prompted ARB to propose 

housekeeping requirements for hexavalent chromium plating and chromic acid anodizing 

facilities to minimize dust. 

1. Barrio Logan Fugitive Emissions – Indoor Air Results

 

During the Barrio Logan study, indoor air samples were collected at two plating facilities. 

The first facility, a hard chromium plating facility had add-on air pollution control devices, 

including a HEPA filtration system. The second facility was a decorative chromium 

plating facility with no add-on air pollution control device or forced ventilation system. 

Indoor samples from the hard chromium plating facility averaged a hexavalent chromium 

concentration of 42.5 ng/m3

, while the average at the decorative plating facility was 

393.4 ng/m3. Continued indoor air sampling at the decorative plating facility yielded 

results as high as 2,315 ng/m3. To put these numbers in perspective, the statewide 

annual average of ambient hexavalent chromium levels was 0.091 ng/m3

 in 2005. Key 

conclusions of this study are: 

• High hexavalent chromium indoor air readings corresponded with high throughput 

(ampere-hour) at the decorative chromium plating facility; 

• High levels of hexavalent chromium seen at ambient sites within the study area 

were consistent with high indoor levels at the decorative chromium plating facility, 
Chapter V Page 50 

indicating that the indoor hexavalent chromium emissions were emitted to the 

outdoors; 

• Dust generated by clean up and construction activities was shown to contain high 

levels of hexavalent chromium (1200 mg/kg or higher), which exited the building; 

and 

• The hard chromium plating facility, with add-on air pollution control devices, had 

low indoor concentrations of hexavalent chromium compared to those at the 

decorative chromium plating facility (ARB, 2003). 

As a follow-up to the Barrio Logan study, SDCAPCD staff took additional samples at 

10 other plating facilities in their district. These results are summarized in Appendix G. 

These data confirm that hexavalent chromium is in the dust at chromium plating and 

chromic acid anodizing facilities. This dust can become re-entrained in the indoor air and 

affect not only the workers at the facility, but also the receptors living near the facility 

when the dust is blown outside. 

 2. ARB - Indoor Air Samples During Source Testing

As we began the emissions testing program, we qualitatively measured indoor levels of 

hexavalent chromium during each test. Samples were taken during the source test and, 

for Phase II, samples were taken during the source test with the temporary hood in place. 

Background samples were also taken without the temporary hood for comparison. These 

results are summarized in Table V-6. 

Table V-6. Summary of Indoor Air Results During Emissions Testing Program 

Test Number Samples 

Range Indoor Air 

Concentration (ng/m3) 

Average Indoor Air 

Concentration (ng/m3) 

Facility 1 5 131* – 391* 262* 

Facility 2 3 106 – 220 174 

Facility 3 3 2.2 – 5.6 4 

Facility 4 6 9.3 - 70 25 

Facility 4 

(background) 4 3.9 - 79 45 

Facility 5 3 39 - 67 57 

Facility 5 

(background) 3 100 – 210 143 

Facility 6 9 150-2350 976 

Facility 6 

(background) 4 120-460 248 

*Total chromium numbers 

Facilities four through six are those facilities that were tested by placing a temporary hood 

over the plating tank. While only qualitative, these data support that hexavalent 

chromium is being emitted from the plating tank during the electrolytic process. The data 

also indicate the presence of hexavalent chromium laden fugitive dust. 
Chapter V Page 51 

REFERENCES 

ARB, 1988b. Air Resources Board. “Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking – Proposed Airborne Toxic Control Measure for Emissions of 

Hexavalent Chromium from Chrome Plating and Chromic Acid Anodizing Operations”. 

1988. 

ARB, 2003. Air Resources Board. “Ambient Monitoring for Hexavalent Chromium and 

Metals in Barrio Logan: May 2001 through May 2002”. 2003. 

SCAQMD, 2003a. South Coast Air Quality Management District. “Draft Staff Report -

Proposed Amended Rule 1469-- Hexavalent Chromium Emissions from Chrome Plating 

and Chromic Acid Anodizing Operations and Proposed Rule 1426- Emissions from Metal 

Finishing Operations.” 2003 

SCAQMD, 2004. South Coast Air Quality Management District. Certified List of Fume 

Suppressants for Facilities Performing Chrome Plating and Chromic Acid Anodizing 

Operations. 2004 (http://www.aqmd.gov/prdas/ChromePlating/ChromePlating.htm) 

SCAQMD, 2004a. South Coast Air Quality Management District. “Hexavalent and Total 

Chromium Emissions from a Decorative Chrome Plating Tank Controlled by Various Mist 

Suppressants”. 2004 

U.S. EPA, 1996. U.S. Environmental Protection Agency. “Emission Factor 

Documentation for AP-42 Section 12.20 – Electroplating – Final Report”. 1996.
Chapter VI Page 52 

VI. Reducing Hexavalent Chromium Emissions 

No new technologies or technology transfers would be required for facilities to comply 

with the proposed amendments to the Chromium Plating ATCM. Hard chromium plating 

facilities, for the most part, have used add-on air pollution control devices such as 

scrubbers, composite mesh pads, and HEPA filters. Decorative chromium plating and 

chromic acid anodizing facilities have mostly used in-tank controls, such as chemical 

fume suppressants and polyballs. These same technologies, or combinations of 

technologies, would allow facilities to comply with the proposed amendments. Generally, 

the proposed amendments would require wider use of add-on air pollution control 

devices. This Chapter describes the types of methods used to control hexavalent 

chromium emissions. 

A. In-tank Controls 

In-tank controls are the most widely used method of reducing hexavalent chromium 

emissions. In-tank controls include chemical fume suppressants which are added directly 

to the plating bath solution and mechanical fume suppressants which float on top of the 

plating bath. Each is described below, along with information on their effectiveness at 

reducing emissions and the number of facilities using them, based on our industry survey. 

 1. Mechanical Fume Suppressants

Mechanical fume suppressants are added to a plating bath’s surface to form a physical 

barrier. These plastic balls (similar in appearance to ping-pong balls), called polyballs, 

act as a barrier to prevent mist from escaping the tank during plating. ARB’s “Senate Bill 

(SB) 1731 Risk Reduction Audits and Plans Guidelines for Chrome Electroplating 

Facilities” assigns for polyballs a 70 percent emission reduction efficiency (ARB, 1997a). 

To achieve this level of emission reduction requires complete coverage of the plating 

bath. Our survey results indicate that polyballs are used by about 60 facilities. Of these 

facilities, about 40 use them in combination with a chemical fume suppressant. One test 

in our emissions testing program evaluated the effectiveness of polyballs in conjunction 

with fume suppressants to reduce emissions. This test yielded an emission rate of 

0.004 milligrams/ampere-hour. However, we cannot measure the efficiency of this 

combination because we did not test the uncontrolled emissions from the bath. 

Polyballs can be a source of fugitive emissions if they are ejected from the tank when 

parts are removed and the solution on the polyballs dries on the floor of the facility. 

Plated parts must be removed from the tank carefully to avoid pulling polyballs out of the 

tank along with the plated part. Polyballs may be a partial control option for facilities 

where there is concern with ‘pitting.’ 
Chapter VI Page 53 

 2. Chemical Fume Suppressants

In the chromium plating process, only about 20 percent of the electrical current applied 

actually deposits chromium onto the part. The remaining current forms bubbles, 

hydrogen gas at the cathode and oxygen at the anode, that rise to the surface of the bath. 

As these bubbles burst, hexavalent chromium is emitted into the air. These bubbles can 

be reduced by adding chemical fume suppressants directly into the plating bath to reduce 

emissions. Emissions are controlled by reducing surface tension of the bath, by forming a 

physical foam blanket across the tank surface during plating, or by using a combination of 

foam blanket and reduced surface tension. The most used type of chemical fume 

suppressant in California’s plating industry are chemicals that reduce surface tension. 

 a. Chemical Fume Suppressants Containing a Wetting Agent

Surface tension is the force that keeps a fluid together at the air/fluid interface. It is 

expressed in force per unit of width such as dynes/centimeter (dynes/cm). Chemical 

fume suppressants that contain ‘wetting agents,’ or surfactants, reduce this surface 

tension. By reducing surface tension, gas bubbles become smaller and rise more slowly 

than larger bubbles. Slower rising bubbles have reduced kinetic energy such that when 

the bubbles do burst at the surface the hexavalent chromium is less likely to be emitted 

into the air, and the droplets fall back onto the surface of the bath (Bayer®). 

The most common types of surfactants used in chromium electroplating and anodizing 

are fluorinated or perfluorinated compounds or, collectively, fluorosurfactants. The active 

ingredients are compounds such as organic fluorosulfonate and tetraethylammonium 

perfluoroctyl sulfonate. The fluorosurfactant-based fume suppressant products used 

today represent an improvement over the previous hydrocarbon-based products. 

Fluorosurfactants are more hydrophobic than hydrocarbon surfactants and they are more 

surface active than hydrocarbon surfactants. Fluorinated sulfonate surfactants are 

effective in highly acidic solutions because they are resistant to hydrolysis by strong acids 

(U.S. EPA 1998). Fluorocarbon chains are also ‘stiffer’ than hydrocarbon chains so they 

are able to pack more closely. For these and other reasons, fluorosurfactants are able to 

reduce surface tension to levels that cannot be reached with hydrocarbon surfactants 

(JPCB, 1999). 

These products are highly effective at reducing hexavalent chromium emissions by 

reducing plating bath surface tension. However, the compounds have been shown to 

bioaccumulate (see further discussion in Chapter XI). The fluorosurfactants used as 

active ingredients in chemical fume suppressants are often referred to as perfluorooctyl 

sulfonates (PFOS). On March 10, 2006, U.S. EPA published at 40 CFR Part 721.9582, a 

proposal to add certain PFOS into their Significant New Use Rule for perfluoroalkyl 

sulfonates (PFAS)(U.S. EPA, 2006). The PFOS proposed for addition include the PFOS 

commonly used in chemical fume suppressants. More information can be found on the 

following website: http://www.epa.gov/opptintr/pfoa/index.htm. 

The notice for the amended Significant New Use Rule indicated that comments were 

being accepted to determine if these PFOS were in current use, such that a potential 
Chapter VI Page 54 

exception could be included. As of this writing, it is unclear as to what U.S. EPA’s final 

action will be. However, it is clear that the PFOS used to control hexavalent chromium 

emissions from chromium plating and chromic acid anodizing have been in use since the 

early 1990’s (P&SF, 2000). Should the U.S. EPA act to include the PFOS in the 

Significant New Use Rule without providing an exception for their use in electroplating, 

the manufacturer or importer would have to seek approval from U.S. EPA to allow their 

use in electroplating. ARB staff will continue to follow developments here, and would 

potentially have to propose regulatory changes depending on the final rule. 

To put the magnitude of surface tension reduction required to suppress hexavalent 

chromium emissions into perspective, consider that the surface tension of water is about 

72 dynes/centimeter. The current ATCM requirement is to reduce surface tension below 

45 dynes/centimeter. Data suggest that lowering the surface tension below 

45 dynes/centimeter reduces emissions further. In fact, product literature from a 

manufacturer of the fluorinated surfactants indicates that maximum emission reduction is 

achieved at 30 dynes/centimeter (Bayer ®). Our testing results did not statistically 

confirm that reducing surface tension to this level reduced emissions further. Balancing 

cost, staff is proposing that surface tension be maintained below 40 dynes/centimeter. 

Another advantage of chemical fume suppressants containing fluorinated surfactants is 

that once a certain concentration is added to the tank, surface tension reduces rapidly 

(Kissa, 1994). Thus, a consistent level of emission reduction is provided. This is further 

justification for requiring facilities to use the chemical fume suppressants that rapidly 

reduce surface tension. 

Earlier generation chemical fume suppressants were thought to cause pitting. Pitting is 

development of small holes or imperfections during plating. This was of particular 

concern in hard chromium plating applications due to the length of time necessary to build 

the desired chromium thickness. Earlier generation chemical fume suppressants, 

although perfluorinated, contained salts. These salts, when mixed with the fluoride ions in 

the plating bath, became suspended and caused roughness, porosity or cracking of the 

chromium plate leading to pits. The chemical fume suppressants in use today no longer 

contain these salts. Thus, chemical fume suppressants used today containing 

fluorosurfactants are no longer a source of ‘pitting,’ and are accepted for use even in hard 

chromium plating applications. However, if the plating bath contains other contaminants 

that may cause pitting, such as chloride, the chemical fume suppressant will accentuate 

the pit (P&SF, 2000 and Jones, 2006). 

The main loss of fluorinated chemical fume suppressants is through dragout of solution 

because fluorinated surfactants are highly stable (U.S. EPA, 1993). Studies have shown 

that the carbon-fluorine (C-F) chemical bond can remain stable when exposed to acids, 

alkali, oxidation, and reduction at relatively high temperatures (Kissa, 1994). Therefore, it 

is not expected that the surface tension of a bath will increase after a few days of use, 

due to chemical breakdown, for these types of surfactants. 

However, surface tension will increase as chemical fume suppressant is lost to drag out 

as parts are removed from the tank. The quantity of chemical lost will depend on 
Chapter VI Page 55 

workload and shop-specific parameters. Dragout can be minimized if electroplated parts 

are sprayed off over the tank, or drip trays are installed to return the surfactant to the tank 

along with the excess chromic acid. 

 b. Foam Blanket Chemical Fume Suppressants

Foam blanket chemical fume suppressants generate a layer of foam on the surface of the 

bath when current is applied. The foam blanket is formed by agitation from the hydrogen 

and oxygen gas bubbles generated during plating. The blanket reduces hexavalent 

chromium emissions by physically entrapping the mist in the foam. 

There are some issues with use of foaming chemical fume suppressants. For example, 

foam blankets need time to form after the current is applied and may also need time to reform after parts are removed, or makeup chemical fume suppressant is added to the bath. 

For shops that use their tanks intermittently, a consistent level of emission reduction is not 

achieved. Under the staff’s proposal, chemical fume suppressants that rely on building a 

foam blanket for emission control could no longer be used. 

Foam blankets also can entrap hydrogen gas, which may result in explosions if a spark is 

generated. This is more of a concern in hard chromium plating than in decorative 

chromium plating, because of the higher current densities and longer plating times 

associated with hard chromium electroplating operations. A foam blanket can also 

reduce the evaporative cooling of a bath, resulting in the need for increased cooling by 

other means (U.S. EPA, 1993). 

 c. Measuring Surface Tension 

Because hexavalent chromium emissions are reduced only at lowered surface tensions, 

accurate measurement of the bath’s surface tension is a critical compliance step. Surface 

tension has traditionally been measured either using a stalagmometer or a tensiometer. 

A du Nouy tensiometer is an instrument that measures surface tension by increasing 

force to a platinum-iridium ring in contact with the surface of the liquid. The tensiometer 

pulls on the ring and measures the force it takes to break the ring from the surface. 

The stalagmometer is an instrument used to measure surface tension by determining the 

mass of a drop of liquid by weighing, a known number of drops or by counting the number 

of drops obtained from a known volume of liquid. Measuring surface tension with a 

stalagmometer is sometimes referred to as the ‘drop weight’ method. A stalagmometer is 

similar to a pipette (CDPHE 1999). Measuring surface tension with the stalagmometer is 

the most often used method, mostly because of cost considerations. 

U.S. EPA's research found that measurements of surface tension with a tensiometer were 

approximately 20 percent lower than those obtained with a stalagmometer 

(U.S. EPA, 2002). Results of surface tension measurements from our emissions testing 

program also confirm that the tensiometer routinely gives lower surface tension readings 

than the stalagmometer. However, we did not see a consistent difference. 
Chapter VI Page 56 

In 2004, U.S. EPA amended the Chromium Plating NESHAP. One of the changes 

establishes different surface tension standards, depending upon the type of measurement 

device used. If a facility uses a stalagmometer to measure surface tension, the surface 

tension should not exceed 45 dynes/centimeter. If a tensiometer is used, the surface 

tension limit is 35 dynes/centimeter (U.S. EPA, 2004). 

Generally, the tensiometer is considered to provide the truer measure of surface tension. 

However, tensiometers can cost thousands of dollars, while stalagmometers only cost 

hundreds of dollars (Hensley, 1997). 

Staff is proposing to incorporate the Chromium Plating NESHAP’s revised surface tension 

requirements into the ATCM. For measuring surface tension the ATCM has referenced 

an U.S. EPA method, Method 306-B, contained in Appendix A of 40 Code of Federal 

Regulations, part 63. This Method 306-B requires use of ASTM Method D 1331-89, 

Standard Test Methods for Surface and Interfacial Tension of Solutions of Surface Active 

Agents, when surface tension is measured with a tensiometer. When measurements are 

taken with a stalagmometer, Method 306-B requires operators to use the instructions that 

came with the measuring device. For standardization, staff is proposing to include, as 

Appendix 8 to the ATCM, a standardized procedure for measuring surface tension with a 

stalagmometer. This method or a method approved by the permitting agency must be 

used to measure surface tension with a stalagmometer. 

 d. Fume Suppressants Used in California

As part of our survey of the chromium plating and chromic acid anodizing industry in 

California, ARB collected information on the types of fume suppressants used. The data 

are summarized in Table VI-1 below. 

Table VI-1. Types of Chemical Fume Suppressants Used in California in 2003 

Fume Suppressant Name 

Numbers 

Using 

Fumetrol 140® 108 

Fumetrol 140® + Dis Mist® 16 

Zero Mist® 10 

Dis Mist NP® 23 

Protab 1000® or Mactec Spray 

Stop®

5 

Fumetrol 101® 5 

Benchbrite® 4 

Chrome Foam 4 

Clepo Chrome Mist Control® 5 

Foam Lok®, Harshaw MSP®, 

EconoChrome®

3 
Chapter VI Page 57 

Of the 230 hexavalent chromium operations, 190 reported use of fume suppressant either 

as the sole control, or with other control devices. Table VI-1 shows the types of chemical 

fume suppressants reported as used by 183 operations for calendar year 2003. The 

other operations did not name the type of chemical fume suppressant used. 

After the survey was conducted, SCAQMD amended their chromium plating and 

anodizing rule. They introduced the chemical fume suppressant certification program. 

The list of certified chemical fume suppressants can be found on their web site at: 

http://www.aqmd.gov/prdas/chromeplating/chromeplating.htm

Because the type of chemical fume suppressant used is critical to the chemical’s ability to 

reduce and maintain lower surface tension, ARB staff also conducted a survey of 

chemical fume suppressant manufacturers to gather information on product formulation, 

mechanism of action, and the surface tension to be achieved for maximum effectiveness. 

The results of the survey are shown in Table VI-2, below. 

Table VI-2. Summary of Chemical Fume Suppressant Mechanism of Control and 

 Recommended Surface Tension 

Chemical Fume Suppressant Primary Mechanism and Surface Tension 

Atotech USA 

 Dis Mist NP® Foam 1-2 inches 

Fumetrol 140® Surface Tension Reducer (30 dynes/cm with a 

tensiometer) 

Benchmark 

Benchbrite CR-1800® Surface Tension Reducer (40 dynes/cm) 

Chemithon-Micel 

Chrome Foam® Surface Tension Reducer (20-30 dynes/cm) 

MacDermid 

Proquel 1299® Surface Tension Reducer (40 dynes/cm) 

 Macuplex STR® Surface Tension Reducer (40 dynes/cm) 

 Clepo Cr Mist Control® Surface Tension Reducer (40 dynes/cm) 

 Enthone® 

Zero-Mist® Surface Tension Reducer (30 dynes/cm) 

(Source: Chemical Manufacturer Survey) 

As shown in Table VI-2, almost all chemical fume suppressants used in California’s 

chrome plating industry control hexavalent chromium emissions by reducing bath surface 

tension. It should also be noted that most manufacturers recommend operating baths at 

40 dynes/centimeter or below for maximum effectiveness. The current ATCM requires 

surface tension to be maintained below 45 dynes/centimeter. The survey also indicates 

that the products that reduce surface tension all use fluorosurfactants as the active 

ingredient. 
Chapter VI Page 58 

B. Add-on Air Pollution Control Devices 

When the Chromium Plating ATCM was first adopted in 1998, hard chromium plating and 

chromic acid anodizing facilities were required to use add-on air pollution control devices 

to comply with hexavalent chromium emission limits (except for smaller operations). A 

number of decorative chromium plating facilities also use add-on air pollution control 

devices to comply with air district health risk rules. From our survey, 113 facilities 

reported using add-on air pollution control devices. Most facilities have either a one stage 

system consisting of composite mesh pad, mist eliminator or scrubber; or a two stage 

system which has a HEPA filter after the first stage. A brief description of the types of 

add-on air pollution control devices currently in use follows. 

 1. High Efficiency Particulate Arrestor (HEPA) Filter 

High Efficiency Particulate Arrestor (HEPA) filters are specifically designed for the 

collection of submicrometer particulate matter at high collection efficiencies. First 

developed in the 1940’s for the Manhattan Project to control radioactive contaminants, 

HEPA filters are rated at 99.97 percent effective in capturing particles 0.3 μm in diameter. 

Particles of 0.3 μm in diameter represent the most penetrating particle size, meaning that 

the 99.97 percent efficiency is the worst efficiency. Smaller or larger particles are trapped 

with higher efficiency (HHS, 2000). When used in particulate air pollution control, HEPA 

filters are best utilized in applications with a low flow rate and low pollutant concentration. 

Typically HEPA filters are installed downstream of another control device to lessen 

loading on the filter, thereby lengthening its life. These products do require maintenance. 

The filters should be replaced at least annually and disposed of as hazardous waste. For 

all but very small facilities, HEPA filters are considered the most effective control of 

hexavalent chromium emissions. They represent BACT and can reduce hexavalent 

chromium emissions to no more than 0.0015 milligrams/ampere-hour. About one-third of 

facilities are already using HEPA filters to reduce emissions. 

 2. Composite Mesh Pad or Dry Scrubber

A Composite Mesh Pad (CMP) system typically consists of several layers of more than 

one monofilament diameter and/or interlocked fibers densely packed between two 

supporting grids. Most systems do exist in two or three stages to ensure collection of reentrainment caused by washdown. A 3 stage system will remove small particles from one 

to 3 μm at about 99 percent efficiency. Each stage can capably remove particles at this 

size but it will take at least 3 stages to reach this efficiency. Filters must be changed 

every one to six years and need to be disposed of as hazardous waste (CDPHE, 1999 

and U.S. EPA, 1998). 

3. Wet Scrubber

A wet scrubber is similar to a CMP system, or Dry Scrubber, except that before the first 

stage of filtration, there is a water washdown of the influent mist in order to increase the 

size of the particles in the mist. In this system, a packing media is used to coalesce these 
Chapter VI Page 59 

larger particles and allow them to drip off into a reservoir at the bottom of the scrubber. 

This “packing” can best be described as a big bag of polypropylene “whiffle” balls. 

4. Fiber-bed Mist Eliminator

A Fiber Bed Mist Eliminator (FBME) removes contaminants from a gas stream through 

the mechanisms of inertial impaction, direct interception, and Brownian diffusion. A 

FBME consists of one or more fiber beds and each bed consists of a hollow cylinder 

formed from two concentric screens designed for horizontal, concurrent gas liquid flow 

through the fiber bed. It is typically installed downstream from another control device to 

prevent plugging (CDPHE, 1999). The filter should last four to six years and needs to be 

disposed of as hazardous waste. According to our survey, this control technology is not 

widely used today in California. 

5. Enclosed Tank Covers

For hard chromium plating and chromic acid anodizing facilities, devices are available to 

totally enclose the plating tank. These containers, sometimes referred to as Merlin 

hoods, form a sealed system to capture the hexavalent chromium emissions within the 

enclosed area. Gasses resulting from plating are vented through a semi-permeable 

membrane which allows the hydrogen and oxygen to exit, but, due to its size, the 

hexavalent chromium does not pass through. Two facilities reported using this 

technology. This technology would not be feasible for decorative chromium plating due to 

the short periods of time that plating actually occurs. 

C. Alternative Processes 

Numerous processes are available, that in some cases, could be used as a replacement 

for some hexavalent chromium plating and chromic acid anodizing operations. Some of 

these processes are briefly described below. 

 1. Trivalent Chromium for Decorative Chromium 

Decorative chromium consists of coatings typically 0.003 to 2.5 μm to provide a bright 

surface with wear and tarnish resistance when plated over a nickel layer. It is used for 

plating, for example, automotive trim/bumpers, bath fixtures and small appliances. An 

option staff considered for this proposal is to phase out hexavalent chromium for 

decorative chromium plating facilities and replace it with the trivalent chromium process. 

This option would eliminate cancer risk from decorative chromium plating facilities 

because trivalent chromium is not considered a carcinogen; however, it is still a toxic 

compound. 

Trivalent chromium baths are currently commercially available for decorative chromium 

plating. In 2003, there were 10 active trivalent chromium operations in California. Of 

these, six are stand alone trivalent chromium operations and four perform both 

hexavalent and trivalent chromium plating for decorative applications. The double cell 
Chapter VI Page 60 

process developed in the 1970’s is improved and has been changed to a single cell 

process, which is easier to maintain. There are many benefits to using a trivalent 

chromium process as well as potential issues. These are presented in the following 

paragraphs. We also provide an example of costs associated with converting from the 

hexavalent chromium decorative plating process to the trivalent chromium process. 

 

a. Benefits and Issues

The greatest benefit to using a trivalent chromium process is reduction in health risk. 

Trivalent chromium is not a carcinogen like hexavalent chromium. However, it has toxic 

effects. As such, it is a U.S. EPA HAP and is a TAC. In the Chromium Plating NESHAP 

and ATCM, emissions from trivalent chromium baths are regulated because of this 

designation. The health effects associated with trivalent chromium are summarized in 

Chapter II. 

In addition to the reduction in toxicity, the trivalent chromium process also has other 

environmental advantages for the plating facility. The total chromium concentration in a 

trivalent chromium bath is significantly less than that of a hexavalent chromium bath. This 

leads to less wastewater and sludge, decreasing the hazardous waste cost for the facility. 

The misting and odor is greatly reduced compared to a hexavalent chromium bath, 

thereby protecting the worker. Trivalent chromium also has better throwing power2

reducing the number of rejects as well as buffing and polishing of parts (P&SF, 2003a). 

In addition to benefits, there are some potential issues with the trivalent chromium 

process. The first issue is the color. The newer baths produce a deposit much closer in 

color to the hexavalent chromium deposit. If a standard trivalent chromium plated part is 

placed more than a few inches away from a hexavalent chromium plated part, most 

consumers would not be able to distinguish between the two deposits. If it placed 

adjacent, manufacturers and consumers might prefer the hexavalent chromium deposit. 

(P&SF, 2003a). To keep the color consistent, the trivalent bath requires careful 

monitoring (Mikhael, 2006). 

The second issue is thickness and corrosion resistance. Trivalent chromium can be 

plated thick enough for decorative purposes. Adhesion and cohesion are as good as 

hexavalent chromium deposits up to at least 1.4 μm (P&SF, 2003a). However, some 

industry representatives believe that for automotive applications, the trivalent deposit is 

not thick enough to meet the step test requirements (Leehy, 2006). The manufacturers 

are working on acceptance of a trivalent finish for the automotive industry and have 

successfully changed the requirements for one company (MacDermid, 2006). Corrosion 

protection is also an issue for automotive applications. Hexavalent chromium ions 

themselves offer some corrosion resistance for the plated substrate by “chromating” the 

part. To achieve the same affect for parts plated with trivalent chromium, posttreatments/dips after plating can be used to produce an equivalent short-term corrosion 

resistance (P&SF, 2003a). Also, trivalent chromium coatings are often deposited over 

nickel layers. The subsequent coating is said to exhibit corrosion resistance comparable 

 

2

 Throwing power is the ability to deposit chromium into the intricate recesses of a particular part. 
Chapter VI Page 61 

to hexavalent chromium when using ASTM B117 salt spray test or the CASS test [1] (AF, 

2000). However, some industry representatives still believe the trivalent plated deposit is 

“too soft” (Lucas, 2006) and will scratch easily. For the end user corrosion resistance is 

reduced and there is no “self healing” benefit (AF, 2001.) 

Cost is another factor to consider when switching from hexavalent to trivalent chromium. 

Most of the equipment used for hexavalent chromium plating can be re-used when 

converting to trivalent chromium. A new synthetic tank lining, graphite anodes, and 

titanium or teflon spaghetti coils should be added for heating and cooling. 

One major manufacturer estimated the costs associated with converting to trivalent 

chromium plating. The costs are shown below in Table VI-3. 

Table VI-3. Cost Estimate for Conversion to Trivalent Chromium 

Operating Cost: Cost Cost for 800

Gallon Tank

Operating cost 

(1,000,000 amp-hr) $0.023/amp-hr $23,000

Equipment/Chemicals: 

Bath make-up $11/gallon $8,800

Graphite anode cost $2.50/gallon $2,000

Ion exchange system $6,000 to $10,000 $10,000

Filter (for carbon) $5,000 to $10,000 $10,000

Air lines $500 $500

Heating/cooling coil (titanium) $2,000 $2,000

Amp-hour meter/feeder $1,200 $1,200

Tank Liner $2,000 to $5,000 $5,000

Conversion to flowing rinse from 

Hexavalent pre-dip $2,000 $2,000

Additional Rinse Tanks varies varies

Subtotal $41,500

Hazardous Waste Disposal: **

Chromic Acid Disposal $4.35/gallon $3,480

Total $67,980

 Source: Atotech 

 **Cost estimate from Filter Recycling Services 

Table VI-3 provides an estimate of the initial costs to convert from the hexavalent 

chromium process to the trivalent chromium process for a decorative plating facility with 

an 800 gallon plating tank and operating 1,000,000 ampere-hours per year. Of course, 

conversion costs would vary depending on an individual operation. A facility converting 

would have one-time equipment and chemical cost of about $41,500 and a chromic acid 

disposal cost (in this example, about $3,500). A facility would also have recurring 

operating costs of $23,000 plus additional chemical costs which would vary depending on 

the operation. A facility may have to install additional rinse tanks. This could lead to 

additional costs to accommodate this tank(s) within an existing plating line (Atotech, 
Chapter VI Page 62 

2006). These costs should only be viewed as an example. An individual facility’s 

conversion costs will also vary based on type of parts plated (substrate and 

configuration), ambient temperatures, bath loading, and racking. 

Staff has evaluated information from manufacturers of the trivalent chromium process, 

relevant literature, information from facility operators currently using the trivalent 

chromium process, and operators that feel they are unable to use the trivalent chromium 

process. We believe that the trivalent chromium process holds promise for the future. 

However, at this time, the trivalent chromium process is not feasible to replace all 

hexavalent decorative chromium plating applications. 

2. Trivalent Chromium for Hard Chrome Plating

Trivalent chromium baths have not been used for hard chromium plating. There is 

difficulty in plating thick chromium coatings with the appropriate properties. Hard 

chromium coatings are typically 1.3 to 760 μm and provide functional properties such as 

hardness, corrosion resistance, wear resistance, and low coefficient of friction. Example 

applications include strut and shock absorber rods, hydraulic cylinders, crankshafts, and 

industrial rolls. 

There has been some recent research funded by the U.S. EPA on developing a process 

for hard trivalent chromium plating. The project is ongoing and a company is working on 

a trivalent chromium process for hard chromium plating (P&SF, 2003). This process is 

not commercially available. 

 3. Other Alternatives

A number of other alternative processes exist for some chromium plating and chromic 

acid anodizing applications. Some of the alternative processes include: 

• Type II Sulfuric Acid Anodizing – often referred to as “regular,” “architectural,” or 

“sulfuric” anodizing. Sulfuric anodize is formed by using an electrolytic solution of 

sulfuric acid at room temperature. The process produces a fairly clear coating and 

is normally used for decorative purposes and provides some corrosion protection 

(IHC, 2006). 

• Electroless Nickel Phosphorous – an auto-catalytic process that deposits a layer of 

nickel alloyed with the reducing agent, phosphorous. The deposit thickness is 

uniform and free of edge buildup because no current is used. Deposits are 

generally semi-bright. The properties include excellent wear, good corrosion 

resistance in many environmental, good lubricity, and improved hardness on many 

substrates (PMPC, 2006). 

• Nickel-Tungsten Electroplating – an electrodeposited alloy of nickel and tungsten. 

The plated deposit exhibits physical and chemical properties similar to chromium 

and electroless nickel. The process is simple to control and can be operated in 
Chapter VI Page 63 

equipment similar to that used for hard chromium plating. A bright or dull finish is 

produced depending on the substrate (Enthone, 2006). 

• Tin-Cobalt Alloy or Tin-Nickel Alloy – Tin-Cobalt alloy is usually plated over bright 

nickel and provides a finish with the appearance of chromium. It is durable and 

wear resistant (Seachrome, 2006). Tin-Nickel deposits can be used as an etch 

resist. It’s most common use is a replacement for hexavalent chromium in 

decorative applications (RPC, 2006).
Chapter VI Page 64 

REFERENCES

AF, 2000. Automotive Finishing. BA Graves. Alternatives to Hexavalent Chromium and 

Chromium Plating. Winter 2000: 

AF, 2001. Automotive Finishing. PC Wynn, CV Bishop. Replacing Hexavalent 

Chromium Plating. Spring, 2001: 

ARB, 1997a. Air Resources Board. “Senate Bill (SB) 1731 Risk Reduction Audits and 

Plans Guidelines for Chrome Electroplating Facilities”. 1997 

Atotech, 2006. Paul Cartwright. Email to ARB staff regarding cost comparisons between 

trivalent and hexavalent chromium electroplating systems. 2006. 

Bayer ®. Product information Bayowet® FT 248 and FT 248R 

CDPHE, 1999. Colorado Department of Public Health and Environment. Chromium 

Maximum Achievable Control Technology (MACT) guidance. Updated April 21, 1999. 

(http://www.cdphe.state.co.us/ap/chromium/html/index.html) 

Enthone, 2006. Cookson Electronics: Enthone. ENLOY® Ni-500. 2006. 

(http://www.enthone.com/functional/index.aspx?Detail=../uc/enloy-ni-500.ascx) 

Hensley, 1997. JE Hensley and D York. “Report on Observed Differences in 

Dynes/Centimeter Readings of Various Chromium MACT Method 306B Surface Tension 

Measuring Devices”. presented at the 18th AESF/EPA Pollution Prevention & Control 

Conference. 1997. 

HHS, 2000. U.S. Department of Health and Human Services. “Primary Containment for 

Biohazards: Selection, Installation and Use of Biological Safety Cabinets”. 2000 

IHC, 2006. IHC, Inc. Sulfuric Anodizing. 2006. (http://www.ihccorp.com/IHCSulf_Anod.htm) 

Jones, 2006. Jones, A.R., Email Communication dated April 17, 2006. 

JPCB, 1999. Journal of Physical Chemistry B. K Wang, G Karlsson and M Almgren. 

Aggregation Behavior of Cationic Fluorosurfactants in Water and Salt Solutions. A 

CryoTEM Survey. 103, 9237-9246. 1999 

Kissa E, 1994. “Fluorinated Surfactants”. Chapter 4, Marcel Dekker, Inc. 1994 

Leehy, 2006. Air Resources Board staff telephone conversation with David Leehy, 

Grover Products. 2006. 

Lucas, 2006. Ray Lucas. Email to ARB staff regarding feasibility of trivalent as an 

alternative to hexavalent chromium plating. 2006 
Chapter VI Page 65 

MacDermid, 2006. Air Resources Board staff telephone conversation with Ken Kraemer 

of MacDermid. 2006 

Mikhael, 2006. Air Resources Board staff telephone conversation with Fiyador Mikhael, 

Bronzeway Plating. 2006 

P&SF, 2000. Plating and Surface Finishing. TD Ferguson, M Zellen, D Brennan and J 

Lutz. Use of Fume Suppressants in Hard Chromium Baths—Quality Testing. February 

2000:67-72. 

P&SF, 2003a. Plating & Surface Finishing. DL Snyder. Distinguishing Trivalent 

Chromium Deposits by Color. November 2003:34-39 

P&SF, 2003b. Plating and Surface Finishing. RP Renz, JJ Fortman, EJ Taylor and ME 

Inman. Electrically Mediated Process for Functional Trivalent Chromium to Replace 

Hexavalent Chromium: Scale-up for Manufacturing Insertion. June 2003:52-58 

PMPC, 2006. Precious Metals Plating Company, Inc. Electroless Nickel. 2006. 

(http://www.pmplating.com/electroless%20nickel.htm) 

RPC, 2006. Reliable Plating Corporation. Tin/Nickel Plating. 2006. 

(http://www.reliableplating.com/tinnickel.html) 

Seachrome, 2006. Seaboard Metal Finishing. Seachrome. 2006. 

(http://www.seaboardmetalfin.com/schrome.htm) 

U.S. EPA, 1993. U.S. Environmental Protection Agency. EPA/453/R-93-030a: 

“Chromium Emissions from Chromium Electroplating and Chromic Acid Anodizing 

Operations - Background Information for Proposed Standards”. 1993. 

U.S. EPA, 1998. U.S. Environmental Protection Agency. EPA/625/R-98/002: “Capsule 

Report Hard Chrome Fume Suppressants and Control Technologies”. 1998. 

U.S. EPA, 2002. U.S. Environmental Protection Agency. “National Emission Standards 

for Chromium Emissions From Hard and Decorative Chromium Electroplating and 

Chromium Anodizing Tanks”. 2002. 

U.S. EPA, 2004. U.S. Environmental Protection Agency. 40 CFR Part 63: “National 

Emission Standards for Chromium Emissions From Hard and Decorative Chromium 

Electroplating and Chromium Anodizing Tanks”. 2004. 

U.S. EPA, 2006. U.S. Environmental Protection Agency. 40 CFR Part 721: 

“Perfluoroalkyl Sulfonates; Proposed Significant New Use Rule.” 2006. 
Chapter VII Page 66 

VII. Health Risk Assessment 

This Chapter presents an overview of the health risk assessment (HRA) process that 

forms the basis for the proposed amendments to the Chromium Plating ATCM. The air 

quality modeling necessary to conduct the HRA is also summarized. Current cancer and 

non-cancer health impacts from exposure to hexavalent chromium from chromium plating 

and chromic acid anodizing operations is also included. 

A. Overview 

A health risk assessment (HRA) is an evaluation or report that a risk assessor (e.g., ARB, 

district, consultant, or facility operator) develops to describe the potential a person or 

population may have of developing adverse health effects from exposure to a facility’s 

emissions. Some health effects that are evaluated include cancer, developmental effects, 

and respiratory illness. For hexavalent chromium, we evaluated the cancer and noncancer health impacts and found that the cancer health impacts were far more significant 

than any non-cancer impacts. Therefore, the following sections focus on the cancer risk 

assessment. Section E contains a discussion of non-cancer health impacts. 

Exposure to TACs can occur through pathways that include inhalation, skin exposure, 

and the ingestion of soil, water, crops, fish, meat, milk, and eggs. OEHHA has 

determined that hexavalent chromium is carcinogenic by the inhalation route only 

(OEHHA, 2003) and does not recommend using a mulitpathway methodology. The 

methods used in this risk assessment are consistent with the Tier 1 analysis described in 

the OEHHA Air Toxics “Hot Spots” Program Risk Assessment Guidelines, the Air Toxics 

Hot Spots Program Guidance Manual for Preparation of Health Risk Assessments 

(OEHHA, 2003). 

B. Health Risk Assessment Process 

The following sections describe the steps in the HRA process and the resulting health risk 

estimates for chromium plating and chromic acid anodizing facilities . 

 1. Hazard Identification

Step one for the risk assessor is to determine whether a hazard exists. If so, the 

assessor identifies the pollutant(s) and the type of effect, such as cancer or respiratory 

effects. In this case, we have determined that hexavalent chromium is emitted from 

chromium plating and chromic acid anodizing facilities. In 1986, the Board formally 

identified hexavalent chromium as a TAC. 

The Board determined that hexavalent chromium exposure causes cancer and there was 

no safe level of exposure where adverse health effects would not occur. When the Board 

identified hexavalent chromium as a TAC, a unit risk factor of 1.5 X 10-1 μg/m3

 was 

established in support of the identification. This means that a lifetime exposure to 
Chapter VII Page 67 

one μg/m3

 of hexavalent chromium would increase an exposed person’s chance of 

developing cancer by about 15 percent. Exposure to hexavalent chromium is known to 

cause lung and nasal cancers, respiratory irritation, severe nasal and skin ulcerations and 

lesions, perforation in the nasal septum, liver and kidney failure and birth defects (ARB, 

1985). Hexavalent chromium is also classified as a human carcinogen by the 

International Agency for Research on Cancer (IARC, 1997). 

2. Dose-Response Assessment

The second step of risk assessment is for the risk assessor to characterize the 

relationship between a person’s exposure to a pollutant and the incidence or occurrence 

of an adverse health effect. This step of the HRA is performed by OEHHA. OEHHA 

supplies these dose-response relationships in the form of cancer potency factors (CPF) 

and reference exposure levels (RELs.) A CPF is used when estimating potential cancer 

risks and RELs are used to assess potential non-cancer health impacts (OEHHA, 1999; 

OEHHA, 2002; OEHHA, 2003). 

Cancer potency factors are the upper bound probability of developing cancer, assuming 

continuous lifetime exposure to a substance at a dose of one milligram per kilogram of 

body weight. To compare the potency of hexavalent chromium with other carcinogens, 

Table VII-1 lists cancer potency factors for various TACs. 

Table VII-1. Inhalation Cancer Potency Factors for Common Carcinogens and 

 Their Relative Potency to Hexavalent Chromium 

Compound 

(in descending order) 

Cancer Potency Factor

(mg/kg-day)-1

Relative Potency 

to Hexavalent 

Chromium 

Dioxin 1.3 X 10+5 250

Hexavalent Chromium 5.1 X 10+2 1

Cadmium 1.5 X 10+1 .029

Arsenic (inorganic) 1.2 X 10+1 .024

Diesel Exhaust 1.1 X 10 .0022

Nickel 9.1 X 10-1 .0018

Benzene 1.0 X 10-1 .0002

Ethylene Dichloride 7.2 X 10-2 .00014

Lead 4.2 X 10-2 .000082

Formaldehyde 2.1 X 10-2 .000041

Perchloroethylene 2.1 X 10-2 .000041

Chloroform 1.9 X 10-2 .000037

Acetaldehyde 1.0 X 10-2 .000020

Trichloroethylene 7.0 X 10-3 .000014

Methylene Chloride 3.5 X 10-2 .000069

 (OEHHA, 2003) 

As shown in Table VII-1, only one other chemical, dioxin, has a higher potential to cause 

cancer than does hexavalent chromium. 
Chapter VII Page 68 

An REL is used as an indicator of potential non-cancer adverse health effects, and is 

defined as a concentration level at or below which no adverse health effects are 

expected. RELs are designed to protect the most sensitive persons in the population by 

including safety factors in their development, and can be created for both acute and 

chronic exposures. An acute exposure is defined as one or a series of short-term 

exposures generally lasting less than 24 hours. Chronic exposure is defined as long-term 

exposure usually lasting from one year to a lifetime. Table VII-2 contains non-cancer 

RELs and toxicological endpoints for hexavalent chromium. 

Table VII-2. Hexavalent Chromium Health Effects Values Used in Non-Cancer 

 Health Risk Assessment 

Non-Cancer Reference 

Exposure Levels (RELs) 

Toxicological Endpoints 

Chronic – Inhalation 0.20 (μg/m3) Respiratory system 

Chronic – Oral 0.02 (mg/kg-day) Hematologic 

*OEHHA 2003 

As shown in Table VII-2, only non-cancer chronic RELs have been determined for 

hexavalent chromium. There is no non-cancer acute REL. Non-cancer impacts linked to 

hexavalent chromium exposure include respiratory irritation, severe nasal and skin 

ulcerations and lesions, perforation in the nasal septum, liver and kidney failure and birth 

defects (ARB, 1985). 

 3. Exposure Assessment

In an exposure assessment, step 3, the risk assessor estimates the extent of public 

exposure by determining people who will likely to be exposed, how exposure will occur 

(e.g., inhalation and ingestion), and the magnitude of exposure. For chromium plating 

and chromic acid anodizing facilities, the receptors (people) that are likely to be exposed 

are residents and off-site workers located near the facility. For this assessment, we 

focused on residential and off-site worker exposures. 

Although on-site workers could be impacted by the emissions, they are not the focus of 

this HRA because the OSHA has jurisdiction over on-site workers. To protect worker 

safety, OSHA has established a PEL for hexavalent chromium of 5 μg/m3

. The PEL is the 

maximum, eight hour, time-weighted average concentration for occupational exposure. 

Because the proposed amendments to the ATCM will require the installation of ventilation 

systems and add-on air pollution control devices for many additional chromium plating 

and chromic acid anodizing facilities, on site-worker exposure to hexavalent chromium at 

the affected facilities would be reduced as well. 

Hexavalent chromium is considered to be carcinogenic only when exposure occurs by the 

inhalation route (OEHHA, 2003.) Therefore, residential and off-site worker locations were 

evaluated via the inhalation pathway only. 
Chapter VII Page 69 

One of the most reliable and cost-effective tools used by ARB staff to evaluate public 

exposures to a pollutant is to conduct air dispersion modeling simulations. The following 

sections summarize the air dispersion modeling conducted to evaluate the health impacts 

from exposure to hexavalent chromium. Further detail on the modeling simulations and 

the input parameters is contained in Appendix H of this report. 

a. Air Dispersion Modeling

To assess the magnitude of exposure, ARB staff used a computerized air dispersion 

model to estimate downwind ground-level concentrations of hexavalent chromium at near 

source locations after it is emitted from a chromium plating or chromic acid anodizing 

facility. The downwind concentration is a function of the quantity of emissions, release 

parameters at the source, and appropriate meteorological conditions. ARB used the 

U.S. EPA’s Industrial Source Complex Short Term (Version 02035) air dispersion model 

(ISCST3 model). The ISCST3 model estimates concentrations at specific locations 

around each facility, directly caused by each facility’s emissions. The modeling inputs 

used are summarized below. 

b. Emission Estimates

Modeled concentrations are based on unit emission rates and can be adjusted to reflect 

any emission rate scenario. Therefore, emissions of hexavalent chromium from 

chromium plating and chromic acid anodizing facilities for this modeling analysis were 

based on an unit emission rate of one gram per second. The mass emission estimates in 

the model are then scaled down to reflect emissions from each chromium plating and 

chromic acid anodizing facility. Thus, the modeling simulation does not “grow” an 

individual facility’s emissions. By scaling the modeled concentrations we are able to 

determine how each facility’s emissions are dispersed into ambient air and the resulting 

concentrations at various distances from the facility. For this analysis staff assumed an 

operating schedule of 9 hours per day, 7 days per week, 52 weeks per year. 

c. Meteorological Data

Four sets of meteorological data representing various locations in California were used for 

this HRA. The data selected are representative of where the majority of chromium plating 

and chromic acid anodizing facilities are located. The four locations, and the years the 

meteorological data represented are Los Angeles area – Pasadena (1981), San 

Francisco Bay area – Oakland (1960-64), San Diego area –Inland (1967-71), Central 

Valley – Fresno (1985-89). 

d. Physical Description of the Source and Emission Release 

Parameters

Six generic chromium plating and chromic acid anodizing facilities were modeled. These 

generic facilities were created from survey information, source test reports, and 

information obtained during site visits from ARB or district staff. Therefore, they are 

representative of the facilities in California. The modeling simulation predicted airborne 
Chapter VII Page 70 

concentrations of hexavalent chromium for potential receptor distances that ranged from 

20 to 1,000 meters (66 – 3,280 feet) from the chromium plating and chromic acid 

anodizing facilities. The assumptions used for modeling emissions from generic facilities 

are shown in Table VII-3 and Table VII-4. 

Table VII-3. Key Parameters for Air Dispersion Modeling and Health Risk 

 Assessment 

Air Dispersion Model: U.S. EPA, Industrial Source Complex Short 

Term (ISCST3), Version 02035 

Source Type: Volume and Point 

Dispersion Setting: Urban 

Receptor Height: 1.2 meters 

Meteorological Data: Los Angeles area - Pasadena 

San Francisco Bay area - Oakland 

San Diego area - Miramar Naval Air Station 

Central Valley - Fresno 

Receptor’s Hypothetical Exposure 

Time: 70 years, 365 days/year 

Adult Daily Breathing Rates: 393 liters/kg body weight-day (high-end) 

302 liters/kg body weight-day (80th 

percentile) 

271 liters/kg body weight-day (mean) 

Adult Body Weight: 70 kg 

Cancer Inhalation Potency Factors: Hexavalent Chromium – 510 (mg/kg-day)-1

Non-Cancer Acute RELs – 

Inhalation: Hexavalent Chromium – not established 

Non-Cancer Chronic RELs – 

Inhalation: Hexavalent Chromium – 0.20 ug/m3

Non-Cancer Chronic RELs - Oral: Hexavalent Chromium – 0.02 mg/kg-day 
Chapter VII Page 71 

Table VII-4. Generic Facility Parameters for Air Dispersion Modeling and Health 

 Risk Assessment 

Stack Information (Point Sources): 

Stack Diameters 0.32, 0.66, and 0.92 meters 

Stack Heights 9.1, 9.1, and 12.8 meters 

Stack Temperatures 24 degrees Celsius 

Stack Exhaust Velocities 10.4, 12.2, and 8.5 meters/second 

Volume Source Parameters: 

Release Height 2.5 meters (ground level) 

Lateral Dimension 2.3, 4.0, and 7.0 meters 

Vertical Dimension 2.3 meters 

Point sources are facilities that already use add-on air pollution control devices with 

forced ventilation systems to collect hexavalent chromium emissions. Exhaust air 

containing any uncollected hexavalent chromium is then vented through a stack. 

Table VII-4 shows the various stack parameters used in the modeling. Note that 

emissions are modeled from the stack, and the stack is assumed to be in the center of the 

building. A typical point source would be a hard chromium plating facility. 

Volume sources are facilities that use only in-tank controls (i.e. chemical fume 

suppressants) to reduce hexavalent chromium emissions. Table VII-4 also shows the 

release parameters of the facilities that were used in the modeling. In this case, the 

source of emissions (the tank) is assumed to be in the center of the building and the 

emissions are modeled from that point. A typical volume source would be a decorative 

chromium plating facility. 

e. Pollutant Specific Health Effects Values

Dose-response or pollutant-specific health values are developed to characterize the 

relationship between a person’s exposure to a pollutant and the incidence or occurrence 

of an adverse health effect. A CPF is used when estimating potential cancer risks and a 

REL is used to assess potential non-cancer health impacts. For ease of the reader, the 

current OEHHA-adopted health effects values for hexavalent chromium are repeated in 

Table VII-3. Note that the cancer inhalation potency factor is 510 (milligrams/kilogramday)-1

. 

Through computerized modeling simulations and using the inputs listed in Tables VII-3 

and VII-4, ARB staff can estimate how concentrations of hexavalent chromium are 

dispersed and diluted into ambient air. These data are then used to determine health 

impacts from chromium plating and chromic acid anodizing facilities. 

Figure VII-1 depicts how concentrations of hexavalent chromium are reduced as they are 

dispersed from the facility. The meteorological data used are from Pasadena. 
Chapter VII Page 72 

Figure VII-1. Percent of Maximum Predicted Concentration of Hexavalent Chromium at 

Increasing Distances from the Source * 

0

20

40

60

80

100

120

20 30 40 50 100 200 500 1000

Distance from Facility in Meters

Percent of Concentration

volume source point source

 * Concentrations using Pasadena meteorological data set and small facility. 

Figure VII-1 shows that concentrations of hexavalent chromium decrease rapidly as they 

are dispersed from a facility. For volume sources (facilities without add-on air pollution 

control devices), at 100 meters the concentration is reduced to 9 percent of the 

concentration at 20 meters. For point sources (facilities with add-on air pollution control 

devices), at 100 meters the concentration is reduced to about 30 percent of the 

concentration at 30 meters. Note also that at 150 meters the concentration from the point 

source has been reduced to about 20 percent of the initial concentration. 

Because of the model’s resolution, for volume sources a receptor is placed at 

20 meters from the edge of the building. This is assumed to be the point of highest 

concentration, or as depicted in Figure VII-1,100 percent. While it is true that the 

concentration of hexavalent chromium would be higher at ten meters from the edge of the 

building, the model has not been validated to provide an accurate concentration at a 

distance less than 20 meters. For the modeled emissions from a small point source, the 

maximum concentration of hexavalent chromium is 30 meters from the edge of the 

building. This distance is the point of highest concentration, or 100 percent. Although not 

shown, a larger point source with a higher stack would have the highest concentration of 

hexavalent chromium at a distance of 50 meters from the source. 

These data indicate that emissions from chromium plating and chromic acid anodizing 

facilities are localized and cancer risk is highest for near-source receptors. 
Chapter VII Page 73 

4. Risk Characterization

To characterize the health risk, the risk assessor combines information derived from the 

previous steps. Modeled pollutant concentrations from the exposure assessment are 

combined with the CPFs (for cancer risk) and RELs (for non cancer effects) derived from 

the dose-response assessment. Risk characterization integrates this information to 

quantify the potential cancer risk and non-cancer health effects. 

For our assessment, Table VII-5 displays the parameters used to calculate both cancer 

and non-cancer health impacts. 

Table VII-5. Key Parameters for Assessing Estimated Cancer and Non-Cancer Health 

 Impacts for Chromium Plating and Chromic Acid Anodizing Facilities 

Point Source Volume Source 

Exposure Residential Residential 

Breathing Rate 80th percentile (302 l/kg) 80th percentile (302 l/kg) 

Meteorological data set Pasadena Pasadena 

Operating Schedule 9 hrs/day, 7 days/week 9 hrs/day, 7 days/week 

Facility Size 

Small (<5,000,000 ampere/hrs) 

Medium (> 5,000,000 

<50,000,000 ampere/hrs) 

Large (>50,000,000 ampere/hrs) 

Small (3,000 ft2) 

Maximum Individual 

Cancer Risk (MICR) 

Distance 

30 meters for small, 

40 meter for medium, 

50 meters for large 

20 meters 

Release Height 

9.1 meters (stack height) for 

small and medium 

12.8 meters for large 

2.5 meters (ground 

level) 

Baseline emissions (2005) of hexavalent chromium for assessing cancer and non-cancer 

impacts from each facility were calculated by multiplying reported throughput (in amperehours) by the facility’s emission rate. For volume source facilities in the SCAQMD, we 

used the emission rate for their certified chemical fume suppressants of 

0.01 milligrams/ampere-hour. All other volume sources in the State were assigned a 

chemical fume suppressant emission rate of 0.04 milligrams/ampere-hour. This is 

consistent with results from our emissions testing program. For point sources, when 

source test data were available, the reported emission rate was used. For other point 

source facilities, emission rates were assigned based on regulatory requirements. 

Based on these assumptions, statewide baseline hexavalent chromium emissions for 

2005 were estimated to be four pounds per year. 

C. Factors that Affect Health Risk Assessments 

The results of an HRA include an evaluation of potential adverse health impacts from 

exposure to a TAC. It is a complex process that requires the analysis of many variables 

to simulate real-world situations. For our purposes, we conducted health risk assessment 
Chapter VII Page 74 

analyses in a manner which is very health protective in estimating cancer risks for a range 

of reasonably foreseeable exposure scenarios. A recent study, funded by ARB, indicted 

that the model employed in this analysis may actually under-predict near-source 

concentrations (UCR, 2003). Staff believe this health protective approach is necessary 

due to the very high potency and resultant serious health hazards associated with 

exposure to hexavalent chromium emissions. There are a variety of factors that can 

affect the results of the HRA for chromium plating and chromic acid anodizing facilities. 

These include: 

• Toxicity of hexavalent chromium; 

• Emission rate of hexavalent chromium from the facility in milligrams/ampere-hour; 

• Source release characteristics (e.g., height of stack, stack configuration, flow rate, 

and building dimensions); 

• Facility operating schedule (duration of exposure); 

• Local meteorological conditions; 

• Distance to the receptor; 

• Duration of exposure; and 

• Inhalation rate of the receptor. 

A combination of these factors will determine the potential health impacts. Due to the 

variability of these factors, the potential health impacts can also vary. For example, if the 

inhalation rate of the receptor were to increase (we have assumed the 80th percentile 

breathing rate), and all other factors were held constant, the resulting potential health 

impacts would also increase. The estimated cancer risks presented are representative of 

the maximum individual cancer risk (MICR). This implies calculation of a cancer risk 

where the concentration of hexavalent chromium is at its maximum upon being emitted 

from a facility. There may or may not be a receptor at this location. 

D. Cancer Risk Assessment 

While the 4.0 pounds (1,800 grams) per year of emissions seems low, even a very small 

amount of hexavalent chromium can result in a substantial cancer risk. For example, staff 

found that as little as two grams of annual emissions would yield an estimated cancer risk 

of ten per million people exposed. As shown in Table VII-6, the maximum individual 

cancer risk (MICR) was determined for each chromium plating and chromic acid 

anodizing facility in California based on these 4.0 pounds of emissions. It should be 

noted that the MICR is calculated using the highest concentration of hexavalent chromium 

downwind of a facility that is predicted by an air quality model. People may not be living 

at the MICR point. Table VII-6 reflects implementation of the current ATCM and air 

district rules, including Rule 1469 for facilities in the South Coast Air Basin. 
Chapter VII Page 75 

Table VII-6. Sixty-three Facilities have Estimated Cancer Risk of Over 10 per 

Million Exposed People (2005 Baseline) 

Number of Facilities by Cancer Risk

<1 

per million 

>1 <10 

per million 

>10 <100 

per million 

>100 

per million 

Baseline 2005 90 67 57 6 

As shown in Table VII-6, 90 facilities (about 41 percent) have estimated cancer risk less 

than one per million exposed people. However, Table VII-6 also shows that 57 facilities 

(about 26 percent) have an estimated cancer risk of over ten per million exposed people. 

Six facilities (about 3 percent) may have an estimated cancer risk of over 100 per million 

people exposed. 

Implementation of Rule 1469 in the South Coast Air Basin provided an improvement in 

cancer risk reduction for facilities located there. In 2003, we estimate that 30 percent of 

facilities had estimated cancer risk of less than one per million exposed people. Overall, 

about 55 percent of facilities had estimated cancer risks below ten per million exposed 

people. Eleven percent of facilities had estimated cancer risk of over 100 per million 

people exposed. These data are not shown graphically. 

Based on these results staff has determined that while Rule 1469 reductions provided risk 

reduction benefits in the SCAQMD it had no impact in reducing cancer risk in other areas 

of the State. We also believe Rule 1469 did not achieve the maximum reduction feasible 

because BACT was not required for all facilities. The staff’s proposal to reduce the 

cancer risk from chromium plating and chromic acid anodizing facilities is described in 

Chapter VIII. 

E. Non-Cancer Risk Assessment 

Non-cancer impacts linked to hexavalent chromium exposure include respiratory irritation, 

severe nasal and skin ulcerations and lesions, perforation in the nasal septum, liver and 

kidney failure, and birth defects (ARB, 1985). We performed a non-cancer risk 

assessment to evaluate potential non-cancer health impacts based on 2005 emissions. 

This year reflects implementation of Rule 1469 in the South Coast Air Basin. The 

assessment included potential impacts from long-term (chronic) exposures. Potential 

chronic and acute health impacts are expressed in terms of a hazard quotient (for a single 

substance.) Typically, a hazard quotient or hazard index that is greater than 1.0 is 

considered to be unacceptable. The parameters that were used to model emissions and 

estimate cancer risk are contained in Tables VII-3, VII-4, and VII-5. 

The analysis indicated that no facility’s hazard index exceeded 1.0 for either worker or 

residential exposure scenarios. In fact, no facility’s hazard index exceeded 0.01. 

Therefore, staff has concluded that no additional measures would be necessary to reduce 

potential chronic non-cancer impacts related to long-term exposure to hexavalent 

chromium from chromium plating and chromic acid anodizing facilities. 
Chapter VII Page 76 

We also analyzed the throughput threshold, in ampere-hours, that could result in a hazard 

index of 1.0. If we evaluate the hazard index for a generic facility and assume amperehours of 100,000,000 (higher than any facility’s throughput in the State) and use the 

assumed emission rate of 0.0015 milligrams/ampere-hour (HEPA level of control), 

ampere-hours would have to increase 100-fold to reach a hazard index of 1.0.
Chapter VII Page 77 

REFERENCES 

ARB, 1985. Air Resources Board. “Staff Report: Initial Statement of Reasons for 

Proposed Rulemaking – Identification of Hexavalent Chromium as a Toxic Air 

Contaminant”. 1985. 

IARC, 1997. World Health Organization – International Agency for Research on Cancer. 

Volume 49: “Chromium, Nickel and Welding, Summary of Data Reported and Evaluation”. 

1997. 

OEHHA, 1999. Office of Environmental Health Hazard Assessment. “Air Toxics Hot 

Spots Program Risk Assessment Guidelines, Part I, The Determination of Acute 

Reference Exposure Levels for Airborne Toxicants”. 1999. 

OEHHA, 2002. Office of Environmental Health Hazard Assessment. “Air Toxics Hot 

Spots Program Risk Assessment Guidelines, Part II, Technical Support Document for 

Describing Available Cancer Potency Factors”. 2002. 

OEHHA, 2003. Office of Environmental Health Hazard Assessment. “Air Toxics Hot 

Spots Program Risk Assessment Guidelines, The Air Toxics Hot Spots Program 

Guidance Manual for Preparation of Health Risk Assessments”. 2003. 

UCR, 2003. Department of Mechanical Engineering, University of California, Riverside. 

“Draft Final Report: Validation of Concentrations Estimated from Air Dispersion Modeling 

for Source-Receptor Distances of less than 100 Meters". 2003.
Chapter VIII Page 78 

VIII. Proposed Risk Reduction Approach and Benefits 

Despite significant reductions in hexavalent chromium emissions, the cancer risks for 

some chromium plating and chromic acid anodizing facilities is still unacceptably high. 

This is largely due to the potent carcinogenicity of hexavalent chromium. As little as two 

grams of annual emissions can elevate the estimated cancer risk to ten per million 

exposed people. The location of many of the facilities also indicates that some low 

income and ethnically diverse communities in the State are disproportionately impacted 

by the emissions. This is of special concern given that 43 percent of facilities are located 

within100 meters of people. These factors compel staff to evaluate emission reduction 

scenarios that minimize or eliminate the cancer risks. 

As described in Chapter VI, staff has evaluated various alternative processes for 

hexavalent chromium plating and chromic acid anodizing to determine if cancer risk could 

be eliminated. While alternatives exist for some applications, their use is limited. Thus, 

we conclude that alternative technologies are not available to require a phase-out of the 

hexavalent chromium process at this time. However, our analysis also shows that 

effective emission reduction alternatives are readily available and these approaches 

minimize the cancer risk to the extent technology allows. 

A. Best Available Control Technology 

Staff has evaluated BACT for chromium plating and chromic acid anodizing facilities. We 

also have evaluated the effectiveness of chemical fume suppressants through our 

emissions testing program. We have determined that add-on air pollution control devices 

with the final capture device being high efficiency particulate arrestor (HEPA) filters 

represents BACT for larger facilities, while use of chemical fume suppressants represents 

BACT for very small facilities. As described in Chapter VI, HEPA filters are rated at 99.97 

percent efficient for collecting particles of 0.3 micrometers in diameter. Use of BACT for 

larger facilities would reduce hexavalent chromium emissions to no more than 0.0015 

milligrams/ampere-hour. There is ample evidence to demonstrate that this is an effective 

method to reduce cancer risk. HEPA filter technology is already used in over 30 percent 

of the facilities to reduce hexavalent chromium emissions. In fact, we are aware that 

facilities currently using various combinations of controls, including HEPA filters, have 

emission rates lower than 0.0015 milligrams/ampere-hour. 

By establishing this level of control, staff has found that emissions, and therefore cancer 

risk, can be minimized. This level of control is 85 percent more effective than the 

emission reductions achieved through use of chemical fume suppressants that have been 

shown to reduce emissions to no more than 0.01 milligrams/ampere-hour. 

Figure VIII-1 shows graphically the effectiveness of HEPA filters compared to chemical 

fume suppressants. 
Chapter VIII Page 79 

Figure VIII-1. Comparison of Cancer Risks (MICR) Remaining After Application of 

Controls at Various Throughputs * 

 

1

0.03 10 1

210

10

25

0

20

40

60

80

100

120

140

160

180

200

MICR*

20,000 200,000 4,000,000 10,100,000

Ampere-hours

0.01 mg/amp-hr** 0.0015 mg/amp-hr***

 * Results are for the inhalation pathway and calculated for a residential receptor with a 70-year exposure 

 duration, 80th percentile daily breathing rate and Pasadena meteorological data set 

 ** Emission rate of a chemical fume suppressant (emission rate 0.01 mg/amp-hr) modeled using a small 

 volume source 

 *** Emission rate of a HEPA filtering system, (emission rate of 0.0015 mg/amp-hr) modeled using a 

 small point source 

Figure VIII-1 shows various throughputs and compares the estimated MICRs resulting if 

emissions are reduced using chemical fume suppressants and by using HEPA filters or 

equivalent controls. Note that a facility using a chemical fume suppressant with 

throughput of 20,000 ampere-hours per year would pose a cancer risk of no more than 

one per million exposed people. This is based on the maximum exposed individual, 

which for volume sources is at 20 meters. At this risk level, chemical fume suppressants 

represent BACT. 

A facility using a chemical fume suppressant and operating 200,000 ampere-hours per 

year poses a cancer risk of ten per million exposed people. However, when BACT for 

intermediate and larger-sized facilities is used, estimated cancer risk is reduced to less 

than one per million exposed persons. HEPA filters or equivalent controls meeting the 

0.0015 milligrams/ampere-hour limit represents BACT. 

Figure VIII-1 also shows that a facility with throughput of 4.0 million ampere-hours would 

have an estimated cancer risk of 200 per million exposed persons if emissions were 

controlled with chemical fume suppressants alone. However, if BACT is used, cancer risk 

would be reduced to ten per million exposed people. 

Finally, Figure VIII-1 shows that once a facility’s throughput exceeds 10.0 million amperehours, even after application of BACT, estimated cancer risk is greater than 

25 per million exposed persons. This indicates that other risk reduction measures may be 

necessary for some facilities. 
Chapter VIII Page 80 

B. Emissions and Cancer Risk Reduction Benefits 

Staff is proposing to amend the Chromium Plating ATCM by phasing in BACT. The 

timing for the application of BACT would be related to throughput and proximity to 

sensitive receptors. BACT for very small facilities would be defined as use of chemical 

fume suppressants. 

The proposed amendments to the Chromium Plating ATCM are found in Appendix A to 

this report and are described in plain English in Chapter IX. As described below, staff 

estimates that by adopting this proposal estimated cancer risk from hexavalent chromium 

emissions could be reduced by up to 85 percent. 

Very low throughput (less than 20,000 ampere-hours per year) facilities would be allowed 

to reduce hexavalent chromium emissions through use of specified chemical fume 

suppressants to lower surface tension of the plating or anodizing bath. This has been 

determined to be BACT for these facilities. Using specified chemical fume suppressants 

to lower surface tension reduces hexavalent chromium emissions to 

0.01 milligrams/ampere-hour. Remaining cancer risk for these facilities would be no more 

than one per million exposed people. 

Application of BACT for all other facilities would require use of control technologies rated 

at 99.97 percent efficient for collecting particles of 0.3 micrometers in diameter. This is 

the control efficiency achieved through installation of a HEPA filter add-on air pollution 

control device. The emission limitation equivalent to this level of control would be 

0.0015 milligrams/ampere-hour. 

Intermediate-sized facilities (greater than 20,000 but less than 200,000 ampere-hours per 

year) would have five years to comply with the emission limitation if the facility is located 

more than 100 meters from a sensitive receptor. This would allow some small 

businesses more time to secure the necessary capital to purchase the needed 

equipment. To provide earlier protection for sensitive receptors, other intermediate-sized 

facilities located at or within 100 meters of a sensitive receptor would be required to meet 

the emission limitation in two years. 

Industry representatives have indicated that combinations of in-tank controls such as 

chemical fume suppressants and polyballs may, in some cases, be able to reduce 

emissions to no more than 0.0015 milligrams/ampere-hour. Therefore, all intermediatesized facilities would be given the option to demonstrate compliance with the emission 

limitation without installation of add-on air pollution control devices. This proposal could 

reduce compliance costs for some small businesses. However, performance testing 

would be required to demonstrate compliance. After full implementation, all intermediatesized facilities would have remaining cancer risk of no more than two per million exposed 

people. 
Chapter VIII Page 81 

The largest facilities (more than 200,000 ampere-hours per year) would be required to 

comply with the emission limitation of 0.0015 milligrams/ampere-hour within two years 

using an add-on air pollution control device(s). Remaining cancer risk for these facilities 

would range from ten to no more than 61 per million exposed people. However, facilities 

with remaining cancer risk over 25 per million exposed people, would be required to 

conduct a refined assessment of their facility’s risk to determine if further risk reduction 

measures would be necessary. 

Table VIII-1 below shows how excess cancer risk would be reduced beyond the risk 

reduction achieved by implementation of the current ATCM and air district rules. 

Table VIII-1. Adoption of Staff’s Proposal Significantly Reduces the Estimated Cancer 

Risk from Hexavalent Chromium Emissions 

 Number of Facilities by Cancer Risk 

<1 

per million 

>1 <10 

per million 

>10 <100 

per million 

>100 

per million 

Staff Proposal 162 41 17 0 

Baseline 90 67 57 6 

As shown in Table VIII-1, by adopting the staff’s proposal about 162 facilities (74 percent) 

would have remaining cancer risk of no more than one per million exposed persons. This 

represents an additional 72 facilities compared to the baseline. Only 17 facilities (about 

8 percent) would have estimated cancer risk of over ten per million exposed people. No 

facilities would have cancer risk exceeding 100 per million exposed people. Under the 

staff’s proposal each facility with residual cancer risk over 25 per million exposed people 

would need to do a site specific analysis to determine if further control measures are 

needed. Total hexavalent chromium emissions from all chromium plating and chromic 

acid anodizing facilities would decrease, by 55 percent, to 1.8 pounds per year. 

Off-site worker cancer risks were also evaluated. Table VIII-2 shows the remaining 

cancer risk for exposed off-site workers if the staff’s proposal were to be adopted. 

Table VIII-2. Adoption of Staff’s Proposal Significantly Reduces the Estimated Cancer 

Risk from Hexavalent Chromium Emissions for Off-Site Workers 

 Number of Facilities by Cancer Risk 

<1 

per million 

>1 <10 

per million 

>10 <100 

per million 

>100 

per million 

Staff Proposal 203 14 3 0 

Baseline 113 70 36 1 

 
Chapter VIII Page 82 

In addition to reducing cancer risk for everyone living near hexavalent chromium and 

chromic acid anodizing facilities, as shown in Table VIII-2, the proposal would also 

provide health benefits for off-site workers. As shown, 92 percent or 203 facilities would 

have cancer risk of no more than one per million exposed off-site workers. This is an 

additional 90 facilities compared to the 2005 baseline. 

These estimates of cancer risk remaining after implementation of the staff’s proposal 

could be either higher or lower. Factors such as meteorology and release characteristics 

of a facility could change the outcome. Additionally, the cancer risk estimates are based 

on a fixed distance, and a facility may or may not have a receptor at that location. If a 

receptor were located less than 20 meters from a facility, their cancer risk could be 

higher. If a receptor were located more than 20 meters from a facility, their cancer risk 

could be lower. Twenty meters is the minimum air dispersion modeling distance used by 

the ARB in the Air Toxics Program. 

C. Other Aspects of the Staff’s Proposal 

Another goal of the amendments is to ensure that new facilities are isolated from sensitive 

receptors. As discussed previously, we have learned that emissions of hexavalent 

chromium have the greatest impact on people living near chromium plating and chromic 

acid anodizing facilities. Our data show that 43 percent of the chromium plating and 

chromic acid anodizing facilities are located within 100 meters of a sensitive receptor. To 

prevent future situations such as this, staff is proposing that any new chromium plating or 

chromic acid anodizing facility not be allowed to operate in an area zoned residential or 

mixed use or within 150 meters of an area zoned residential or mixed use. At this 

distance, 150 meters, (~500 feet), modeling for point sources shows that the hexavalent 

chromium concentration has dropped off by about 80 percent. 

Nevertheless, staff is also proposing that facilities would have to conduct a site specific 

health risk assessment to ensure that public exposure to emissions from the new source, 

will be below the air districts’ levels of significance contained in health risk rules and 

policies. This proposal provides a margin of safety and accounts for situations where 

receptors may move in closer to a facility. 

While they cannot be quantified because of variation from facility to facility, fugitive dust 

emissions also likely impact people residing near chromium plating and chromic acid 

anodizing facilities. Information on fugitive dust emissions is contained in Chapter V. 

Therefore, staff is proposing that all facilities would need to implement housekeeping 

measures to reduce dust emissions. We have found that fugitive emissions related to 

poor housekeeping can be an additional source of hexavalent chromium emissions. 

Training explaining the Chromium Plating ATCM and the requirements, conducted by 

ARB staff, would be required every two years for employees responsible for compliance 

at chromium plating and chromic acid anodizing facilities. An exception to this 

requirement would be personnel that had attended the SCAQMD’s training class for 

Rule 1469. 
Chapter VIII Page 83 

The proposal would also prohibit the sale or use of chromium plating or chromic acid 

anodizing materials unless sold or used by individuals or businesses under air district 

permit to conduct such operations. 

All of these proposals, as well as the provisions necessary to implement them, are 

described further in Chapter IX. 
Chapter IX Page 84 

IX. Proposed Amendments and Alternatives 

Staff is proposing to amend the Chromium Plating ATCM (title 17, California Code of 

Regulations, section 93102). As described below, the amended ATCM will now be 

contained in sections 93102 through 93102.16. The amendments are being proposed to 

further reduce the public's exposure to emissions of hexavalent chromium. If adopted, 

the staff’s proposal would reduce the estimated cancer risk by up to 85 percent. This 

Chapter is provided to describe, in “plain English,” the changes being proposed. The 

rationale for the proposal is also described. The text of the proposed amendments to the 

ATCM can be found in Appendix A to this staff report. This Chapter also discusses 

alternative emission reduction approaches that were evaluated. 

A. Summary of the Existing Airborne Toxic Control Measure 

Chromium plating and chromic acid anodizing facilities have been regulated to control 

hexavalent chromium emissions since 1988 when the ATCM was first adopted. The 

regulation established different limits based on facility throughput and type of operation. 

Hard chromium plating and chromic acid anodizing facilities, except for small hard 

chromium plating facilities, were required to control hexavalent chromium emissions by 

meeting emission limitations using add-on air pollution control devices. The stringency of 

the limits depended on throughput, with the highest volume facilities meeting the most 

restrictive limit. Decorative chromium plating facilities, on the other hand, were required 

to control hexavalent chromium emissions, but to a lesser extent than hard chromium 

plating facilities. Most decorative chromium plating facilities chose to comply by using 

chemical fume suppressants. 

The regulation was amended in 1998 to incorporate changes necessary for equivalency 

with the federal Chromium Plating NESHAP. This included changing the requirements for 

chromic acid anodizing facilities to harmonize them with the requirements for decorative 

chromium plating facilities, and requiring control of emissions from trivalent chromium 

plating facilities. 

B. Summary of the Proposed Amendments 

The staff is proposing a complete renumbering of the Chromium Plating ATCM. Rather 

than having alphabetized subsections to section 93102, staff is proposing to number 

sections consecutively in order to make the regulation easier to read. For example, 

previous subsection (a) would be renumbered to section 93102.1. This convention would 

be followed throughout the ATCM. 

Section 93102 would set forth the organization of the regulation and clarify where 

requirements pertaining to a specific facility could be found. The reorganized ATCM 

would be contained in sections 93102 through 93102.16.
Chapter IX Page 85 

1. Section 93102.1--Applicability

Applicability requirements were previously contained in subsection (a). We are proposing 

a modification to the Applicability section. Originally the regulation’s applicability was to 

“each chromium electroplating or chromic acid anodizing tank at a facility.” Staff is 

proposing that the regulation applies to any owner or operator of a facility performing hard 

chromium electroplating, decorative chromium electroplating, or chromic acid anodizing. 

We are proposing this change to clarify that the requirements apply facility-wide. 

Ultimately, compliance responsibility is placed upon the owner or operator, therefore, this 

change would provide clarification. 

Other changes are proposed to section 93102.1. We are also proposing to extend the 

applicability of the ATCM to manufacturers or distributors of chromium plating or chromic 

acid anodizing kits. This is necessary to implement other provisions of the proposal. 

Staff is proposing a provision that would allow the ATCM to remain in effect if an 

individual part of the ATCM is found to be invalid. This severability provision is contained 

in many ARB regulations and is designed to insure that the control of hexavalent 

chromium emissions will continue even if a particular provision of the ATCM is held to be 

invalid by a court. 

 2. Section 93102.2--Exemptions

Exemptions were previously contained in subsection (a). We are not proposing any new 

exemptions within the ATCM. The proposal would move the existing exemptions to their 

own section. Generally, the exemptions exclude process tanks where chromium plating 

or chromic acid anodizing does not occur. The exemptions also clarify that the provisions 

for inspection and maintenance do not apply during breakdown conditions. 

 3. Section 93102.3--Definitions

Definitions were previously contained in subsection (b). Staff is proposing to modify a 

number of definitions, and is also proposing several new definitions necessary to 

implement other proposals in the regulation. The modified definitions are intended to 

further clarify the existing definitions. The proposed amended definitions are shown in 

Table IX-1 below. 
Chapter IX Page 86 

Table IX-1. Definitions Proposed for Modification 

Base metal Modification 

Chromic acid anodizing Foam blanket 

Chromium electroplating or 

chromic acid anodizing tank 

Hard chromium electroplating or 

industrial chromium electroplating 

Composite mesh-pad system High Efficiency Particulate Arrestor 

(HEPA) filter 

Decorative chromium electroplating Mechanical fume suppressant 

Emission limitation Packed-bed scrubber 

Facility Stalagmometer 

Fiber-bed mist eliminator Tensiometer 

One definition proposed for amendment, “Modification,” warrants a further explanation. 

The definition for “Modification” is intended to describe changes to a facility that would 

trigger additional requirements. Presently, a facility is not considered “Modified” if 

throughput increases, as long as the maximum design capacity of the equipment is not 

exceeded. One amendment proposed by staff would define a modification as a change in 

throughput that would cause a facility to be subject to a different emission limitation. We 

are also proposing that changes to a permit unit or addition of a permit unit that does not 

increase hexavalent chromium emissions would not be considered a modification. These 

changes are necessary to implement the emission limit requirements in section 93102.4. 

Several new definitions are proposed to implement other proposals in the Chromium 

Plating ATCM. Other definitions are proposed to further clarify the ATCM. The proposed 

new definitions to be added are shown in Table IX-2. 

Table IX-2. New Definitions Proposed for Addition 

Annual Permitted Ampere-hour Modified Facility 

Dragout New Facility 

Enclosed storage area Owner or Operator 

Enclosed hexavalent chromium 

electroplating tank 

Permitting Agency 

Existing Facility Person 

Fugitive dust Sensitive receptor 

Initial start-up Tank 

Most of these proposed new definitions are necessary to implement housekeeping 

requirements and other measures designed to reduce emissions of hexavalent chromium 

laden fugitive dust. Other proposed definitions are designed to clarify what constitutes an 

existing, new or modified facility, and others define those responsible for compliance or 

oversight. 

One new definition proposed, “Sensitive receptor,” warrants further explanation. A 

sensitive receptor is proposed to be defined as “any residence including private homes, 

condominiums, apartments, and living quarters; education resources such as preschools 
Chapter IX Page 87 

and kindergarten through grade twelve (K-12) schools; daycare centers; and health care 

facilities such as hospitals or retirement and nursing homes. A sensitive receptor 

includes long term care hospitals, hospices, prisons, and dormitories or similar live-in 

housing.” This is the same definition used in the ATCM to Reduce Emissions of 

Hexavalent Chromium and Nickel from Thermal Spraying (title 17, CCR, section 

93102.5), which was adopted by the Board in 2005. The definition is necessary to 

implement the proposed hexavalent chromium emission limit requirements in subsection 

93102.4. As will be explained below, the requirements to control hexavalent chromium 

emissions will be phased in on different dates depending on a facility’s distance to a 

sensitive receptor. Data show that sensitive receptors located in close proximity to 

hexavalent chromium plating or chromic anodizing facilities are at greater risk of exposure 

to elevated levels of hexavalent chromium. Note that as proposed, a residence would be 

considered a sensitive receptor. This is because children, the elderly, and other healthcompromised individuals are often located in residences. 

 4. Section 93102.4--Emission Limits

Emission limitations for hexavalent chromium were previously contained in 

subsection (c) and would now be contained in section 93102.4. A number of 

organizational changes are proposed including renaming the section to “Requirements for 

Existing, Modified, and New Hexavalent Chromium Plating and Chromic Acid Anodizing 

Facilities.” Other organizational changes are necessary to clarify that the existing limits 

would remain in effect until the proposed new limits would become effective. The section 

would be divided into requirements that continue to apply until the new requirements 

become effective. 

a. Proposed subsection (a), Existing Hexavalent Chromium Limits

In section 93102.4, clarifying language is proposed to help the owner or operator to 

understand when the existing limits would no longer be effective and when compliance 

with the newly proposed limits would be required. As proposed, subsection 93102.4(a) 

would contain the current limits for existing hexavalent chromium facilities, and the limits 

for new or modified facilities up until the effective date of the new limits. Subsection (a)(1) 

applies to hard chromium plating facilities while subsection (a)(2) applies to decorative 

chromium plating and chromic acid anodizing facilities. Language is also proposed to 

specifically list all of the sections that contain other requirements that must be complied 

with, in addition to the limits set forth in section 93102.4. 

 b. Proposed subsection (b), New Hexavalent Chromium Limits 

Proposed subsection (b) would contain the proposed new requirements for existing 

hexavalent chromium facilities to reduce emissions. Rather than continued bifurcation of 

requirements, staff is proposing that all facilities using the hexavalent chromium process, 

whether they perform decorative plating, hard plating, or chromic acid anodizing, would 

be subject to the same requirements. Based on emissions testing results, staff believes 

that uncontrolled emissions from these sources are similar and that each source of 

hexavalent chromium emissions should be controlled in the same manner and to the 
Chapter IX Page 88 

same degree. Also, based on our analysis of health risks in Chapter VIII, staff is also 

proposing that limits be phased in based on throughput, cancer risk, and proximity to 

sensitive receptors. 

The proposed amendments to the ATCM would require best available control technology 

(BACT) to further reduce the public’s exposure to hexavalent chromium from chromium 

plating and chromic acid anodizing facilities. BACT would apply to all facilities over time. 

For very small facilities BACT is use of specific chemical fume suppressants. BACT for 

all other facilities is a HEPA filtration system, or equivalent control. The requirements that 

would apply to each class of facility are specified in Table 93102.4, and are described 

below. 

Very low throughput (< 20,000 ampere-hours per year) facilities would be allowed to 

reduce hexavalent chromium emissions through use of specified chemical fume 

suppressants to lower surface tension of the plating or anodizing bath. This represents 

BACT for these facilities. Using specified chemical fume suppressants to lower surface 

tension reduces hexavalent chromium emissions to 0.01 milligrams/ampere-hour. 

Alternatively, these facilities may choose to comply by installing add-on air pollution 

control devices. Staff estimates that using specified chemical fume suppressants would 

result in a remaining cancer risk of no more than one per million people exposed. The 

chemical fume suppressants to be used for compliance are displayed in Table 93102.8 of 

section 93102.8. 

Application of BACT for all other facilities would require use of control technologies rated 

at 99.97 percent efficient for collecting particles of 0.3 micrometers in diameter. This is 

the control efficiency achieved through installation of a HEPA filter add-on air pollution 

control device. The emission limitation equivalent to this level of control would be 

0.0015 milligrams/ampere-hour. Staff is also proposing that intermediate-sized facilities 

be allowed to control emissions with devices other than HEPA filters, as long as a 

performance test demonstrates hexavalent chromium emissions to be no more than 

0.0015 milligrams/ampere-hour. The timing for requiring compliance would be based on 

annual ampere-hours, health risk, and proximity to sensitive receptors. 

Intermediate-sized facilities (> 20,000 and < 200,000 ampere-hours per year) would have 

five years to comply with the emission limitation if the facility is located more than 

100 meters from a sensitive receptor. To protect sensitive receptors, other intermediatesized facilities located at or within 100 meters of a sensitive receptor would be required to 

meet the emission limitation in two years. All intermediate-sized facilities would be given 

the option to demonstrate compliance with the emission limitation without installation of 

add-on air pollution control devices. These proposals are designed to potentially reduce 

compliance costs for smaller businesses. Staff estimates that meeting the emission limit 

of 0.0015 milligrams/ampere-hour would result in a remaining cancer risk of no more than 

one per million people exposed. 

The largest facilities (> 200,000 ampere-hours per year) would be required to comply with 

the emission limitation of 0.0015 milligrams/ampere-hour within two years using an 

add-on air pollution control device(s). After meeting the emission rate, we estimate that 
Chapter IX Page 89 

85 percent of larger facilities would have a remaining cancer risk of less than 

10 per million people exposed. Less than one percent of facilities would have cancer risk 

of more than 25 per million people exposed. Those facilities with cancer risk of over 

25 per million would be required to conduct an additional risk analysis, based on the 

individual facility’s specific conditions and parameters to determine if further risk reduction 

would be required. Staff estimates that about 15 grams of emissions from a small point 

source would result in a cancer risk of over 25 per million people exposed. This site 

specific analysis could lead to measures to further reduce cancer risk. 

Table IX-3 summarizes the requirements for compliance with the emission limitations. In 

the regulation, this table is labeled “Table 93102.4” and is set forth in section 93102.4. 

Table IX-3. Proposed Hexavalent Chromium Emission Limits for Existing Facilities 

Tiers of 

Annual 

Permitted 

Ampere-Hours

Sensitive 

Receptor 

Distance 1

Emission Limitation Effective Date 

Tier 1 

< 20,000 Any 

Use Chemical Fume Suppressant as 

specified in section 93102.8 2

[Six Months after 

Effective Date] 

Tier 2 

> 20,000 and 

< 200,000 

< 100 

Meters 

0.0015 milligrams/ampere-hour 3[Two Years after 

Effective Date] 

Tier 3 

> 20,000 and 

< 200,000 

> 100 

Meters 

0.0015 milligrams/ampere-hour 3[Five Years after 

Effective Date] 

Tier 4 

> 200,000 

Any 0.0015 milligrams/ampere-hour 4, 5 [Two Years after 

Effective Date] 

1

 Distance shall be evaluated by the permitting agency. 

2

 Alternatively, [Two Years after Effective Date] facility shall comply with the requirement for facilities 

with > 20,000 and < 200,000 annual permitted ampere-hours. 

3

 Emission limit compliance can be demonstrated without add-on air pollution control device. 

4 Measured after add-on air pollution control device. 

5

 When actual annual emissions exceed 15 grams, a site specific analysis must be conducted in 

 accordance with the permitting agency’s procedures.

In proposed subsection 93102.4(b)(2), language is provided to explicitly indicate that 

facilities within Tier 2 or Tier 3 can demonstrate compliance without using an add-on air 

pollution control device. However, at a minimum, these facilities would have to use the 

chemical fume suppressants specified in section 93102.8. This subsection would also 

specify that facilities in Tier 4 would be required to use an add-on air pollution control 

device to demonstrate compliance. 

 
Chapter IX Page 90 

c. Proposed subsection (c), Modified Facilities

As mentioned above in the ‘Definitions’ section, staff is proposing to change the definition 

of ‘Modification’ to include increases in throughput (measured as ampere-hours) that 

would result in the facility moving to a different tier of control. To protect public health, a 

facility wishing to modify operations would be required to control hexavalent chromium 

emissions by installing an add-on air pollution control device to reduce hexavalent 

chromium emissions to a rate of no more than 0.0015 milligrams/ampere-hour. 

To evaluate if a facility continues to pose an unacceptable health risk after installation of 

state-of-the-art add-on air pollution control devices, an additional requirement is 

proposed. Facilities whose emissions exceed 15 grams per year would need to conduct 

a site specific analysis to determine if further risk reduction measures are necessary. 

Staff estimates that about 15 grams of emissions from a small point source would result in 

a cancer risk of over 25 per million people exposed. 

 d. Proposed subsection (d), New Facilities

As explained in Chapter I, chromium plating and chromic acid anodizing operations can 

create “Hot Spots,” with emissions that have a maximum impact near-source. Our data 

also show that 43 percent of existing facilities are located near people, which has led to 

unacceptable exposures to hexavalent chromium emissions. To avoid future situations 

where residential units or sensitive receptors are located in very close proximity to a 

chromium plating or chromic acid anodizing facility, staff is proposing that a new facility 

cannot operate in an area zoned for residential or mixed use. In addition, the facility also 

could not operate within 150 meters from the boundary of any area zoned as residential 

or mixed use. Modeling results indicate that at this distance the concentration of the 

hexavalent chromium emissions has been reduced to about 20 percent of the original 

near source concentration. 

However, staff is proposing to include provisions that the new facility would be deemed to 

meet this requirement as long as the facility met the separation requirement when the 

authority to construct was issued by the permitting agency (and substantial use of the 

authority to construct takes place within one year after it is issued), or met the 

requirement before any land use zoning changes occur. 

Even with this separation requirement, staff is proposing that any new facility would be 

required to control hexavalent chromium emissions by installing a HEPA add-on air 

pollution control device and demonstrate that the hexavalent chromium emission rate 

after the HEPA add-on air pollution control device is no more than 

0.0015 milligrams/ampere-hour. Under the proposal, all new facilities would be required 

to conduct a site-specific analysis to determine if further risk reduction measures are 

necessary. 
Chapter IX Page 91 

e. Proposed subsection (e), Notification Requirements for New and 

Modified Sources

The requirements of proposed subsection 93102.4(e) have been moved from former 

subsection (j). Minor modifications to the language were also made to improve clarity. 

These requirements, relating to new and modified facilities, specify other requirements 

that must be met prior to a facility undergoing modification or prior to a new facility 

beginning operation. 

5. Proposed Section 93102.5--Additional Requirements 

Within new section 93102.5, requirements are proposed that apply to all hexavalent 

chromium plating and chromic acid anodizing facilities (i.e., all existing, modified, and new 

facilities). 

Staff is proposing, in subsection (a), that any facility with an add-on air pollution control 

device(s) could not remove the device, unless it is replaced with an add-on air pollution 

control device(s) meeting an emission rate of 0.0015 milligrams/ampere-hour. Requiring 

that the add-on air pollution control device remain in place provides an extra margin of 

safety. 

ARB staff recognizes that the ATCM has many requirements that may be difficult to 

understand or carry out correctly without training. Staff also knows that following the 

requirements are necessary to control hexavalent chromium emissions effectively. 

Therefore, in subsection (b), we are proposing that every two years personnel designated 

by the owner or operator as responsible for environmental compliance must attend an 

ARB training class explaining how to comply. An exception to this requirement would be 

personnel that had attended the SCAQMD’s training class for Rule 1469, which is also 

required every two years. 

Fugitive emissions, essentially dust containing hexavalent chromium, can be an important 

contributor a facility’s overall emission impact. While these emissions are difficult to 

quantify, we nevertheless believe measures are necessary to minimize these fugitive 

emissions. We are therefore proposing housekeeping measures in subsection (c) to 

reduce the mechanisms by which hexavalent chromium may be accidentally splashed or 

spilled, and are also proposing housekeeping measures to reduce dust that may become 

re-entrained into the ambient air. 

To limit the generation of hexavalent chromium dust, staff’s proposal includes: 

• Storing chemicals such as chromic acid in closed containers in enclosed storage 

areas; 

• Transporting chemicals to the plating or anodizing bath in closed containers; 

• Cleaning up or containing liquid or solid spills that may contain hexavalent 

chromium within an hour of the spill occurring; 

• Minimizing dragout by: 

- For automated lines: requiring drip trays between tanks; 
Chapter IX Page 92 

- For manual lines: requiring that dragout be minimized. When parts are 

sprayed off over the tank with fresh water, a splash guard would be required 

to ensure water from the part rinsing is returned to the tank; 

• Cleaning of surfaces, such as floors, walkways around tanks, and storage areas 

that potentially are contaminated with hexavalent chromium at least once every 

seven days; 

• Installing a barrier, such as plastic strip curtains, to separate buffing and grinding 

areas from the plating tank area; and 

• Requiring that all waste/dust from housekeeping practices be disposed of properly 

as hazardous waste. 

6. Proposed Section 93102.6--Requirements for Trivalent Chromium 

Baths and Enclosed Hexavalent Chromium Electroplating Facilities

The requirements for trivalent chromium plating facilities were previously contained in 

subsection (c). Proposed new section 93102.6 would specify the requirements for 

facilities electroplating with the trivalent chromium process and for facilities employing an 

enclosure around the plating tank to control hexavalent chromium emissions. 

Generally, the requirements for facilities plating with trivalent chromium would be 

unchanged (subsection (a)). However, even though trivalent chromium is not considered 

a carcinogen, its use is not without some health impacts. Therefore, we are proposing 

that the separation requirements (in section 93102.4(d)(1)) for new hexavalent chromium 

facilities also apply to new trivalent chromium plating facilities. 

Like the provision for new hexavalent chromium plating or chromic acid anodizing 

facilities, no new trivalent chromium facility could operate if it were located within an area 

zoned residential or mixed use, or if it were to be located within 150 meters from the 

boundary of any area zoned residential or mixed use. 

Subsection 93102.6(a) also specifies which requirements of the ATCM an owner or 

operator of a trivalent chromium plating facility does not need to comply with. 

The requirements in subsection (b) relating to enclosed hexavalent chromium tanks are 

being proposed to incorporate changes to the federal Chromium Plating NESHAP. As 

described by U.S. EPA, ventilation rates for enclosed tanks are considerably lower than 

ventilation rates for conventional ventilated facilities. Because of this, some facilities with 

enclosed tanks had difficulty meeting the chromium emission concentration limit specified 

in the Chromium Plating NESHAP, even when emissions from those tanks are well 

controlled. To rectify the situation, U.S. EPA adopted a separate alternative mass 

emission rate limit for chromium electroplating tanks equipped with enclosing hoods (U.S. 

EPA, 2004). We are proposing to add these provisions to the Chromium Plating ATCM. 

Alternatively, these facilities may opt to comply with an emission rate of 

0.0015 milligrams per dry standard cubic meter of air as measured after the add-on air 

pollution control device, or use a specified chemical fume suppressant. 
Chapter IX Page 93 

New enclosed hexavalent chromium plating facilities would also be subject to the 

separation requirements described above for new trivalent chromium plating facilities. 

7. Proposed Section 93102.7--Performance Testing and Test Methods

Performance testing and test methods were previously contained in subsection (d). Many 

of the proposed new regulatory requirements require facilities to determine the actual 

hexavalent chromium emission rate after the add-on air pollution control device(s). In this 

subsection, we are specifying the facilities that would have to conduct a performance 

(source) test to demonstrate compliance. As proposed, the following types of facilities 

would need to conduct a source test: 

• Existing facilities demonstrating compliance with the 0.0015 milligrams/amperehour hexavalent chromium emission limitation; 

• Facilities that undergo modification; 

• Any new facility; and 

• Trivalent chromium plating facilities meeting the emission rate in subsection 

93102.6(a)(1). 

All of these types of facilities would have to conduct the performance test within 60 days 

of initial start-up using an approved test method. 

Facilities would be able to use an existing source test if it was conducted after 

January 1, 2000, and the test demonstrated an emission rate of 

0.0015 milligrams/ampere-hour, or less. The test would need to have been approved by 

the permitting agency using an approved test method. The test results would also need 

to be representative of the air pollution control device(s) currently in use. 

Minor modifications are proposed to subsections (c) and (d). One modification to the 

Approved Test Methods in subsection (c) would clarify that any performance test must 

include three test runs. Under another proposal, to measure surface tension with a 

tensiometer continued use of U.S. EPA Method 306-B would be required. When 

measuring surface tension with a stalagmometer, the method in new proposed 

Appendix 8, or a method approved by the permitting agency would need to be used. 

Identifying a specific procedure will provide more accurate and uniform results. In 

subsection (d), clarifying language is proposed to identify that the pre-test protocol is to 

be submitted to the permitting agency. 

8. Proposed Section 93102.8--Chemical Fume Suppressants Used for 

Compliance

Results of our emissions testing program, along with results from the SCAQMD 

certification program, demonstrated that certain chemical fume suppressants were more 

efficient than others at reducing hexavalent chromium emissions. To ensure maximum 

reduction of hexavalent chromium from facilities using chemical fume suppressants, staff 

is proposing to specify the types of chemical fume suppressants that could be used to 

reduce surface tension. The chemical fume suppressants that could be used are listed 
Chapter IX Page 94 

below in Table IX-4, along with the surface tension at which they must be used. Based 

on our emissions testing program and analysis of results from the SCAQMD Fume 

Suppressant Certification Program (SCAQMD, 2004), staff has determined that the 

chemical fume suppressants listed in Table IX-4 are most efficient for preventing 

emissions of hexavalent chromium. In the regulation, Table IX-4 is labeled “Table 

93102.8” and is set forth in section 93102.8(a). 

Table IX-4. Chemical Fume Suppressants Approved for Use at 

 Specified Surface Tensions 

Chemical Fume 

Suppressant and 

Manufacturer 

Stalagmometer 

Measured 

Surface Tension 

(dynes/centimeter) 

Tensiometer 

Measured Surface 

Tension 

(dynes/centimeter)

Benchbrite CR 1800® 

Benchmark Products < 40 < 35 

Clepo Chrome® 

MacDermid < 40 < 35 

Fumetrol 140® 

Atotech U.S.A. < 40 < 35 

Staff is also proposing that additional chemical fume suppressants may be used upon 

approval by the ARB Executive Officer, if specified criteria are met. A provision to revoke 

use of a specified chemical fume suppressant, if it is found to no longer meet an emission 

rate of 0.01 milligrams/ampere-hour or less, is also proposed. This provision is necessary 

to protect public health. 

9. Proposed Section 93102.9--Parameter Monitoring

Parameter monitoring requirements were previously contained in subsection (e). Minor 

changes are proposed to section 93102.9, Parameter Monitoring, to clarify existing 

provisions. 

10. Proposed Section 93102.10--Inspection and Maintenance 

Requirements

Inspection and maintenance requirements were previously contained in subsection (f). 

Changes are proposed to section 93102.10, Inspection and Maintenance Requirements, 

to consolidate the requirements where appropriate. A new provision is proposed for 

facilities that have custom designed add-on air pollution control devices. The owner or 

operator of such a facility would be required to develop operation and maintenance 

requirements for review and approval by the permitting agency. 
Chapter IX Page 95 

11. Proposed section 93102.11--Operation and Maintenance Plan 

Requirements

Operation and maintenance plan requirements were previously contained in 

subsection (g). Minor modifications are proposed to section 93102.11. The proposed 

changes are necessary to update citations for other subsections which have been 

reorganized. 

12. Proposed section 93102.12--Recordkeeping

Recordkeeping requirements were previously contained in subsection (h). Minor 

modifications are proposed to section 93102.12, Recordkeeping. Most of the 

modifications clarify the provisions or update citations within the ATCM. Also, as 

proposed, section 93102.12, would be modified to specify additional records that must be 

kept. Facilities would be required to maintain monthly records of total ampere-hour usage 

per calendar year to verify compliance with the emission limit that corresponds to the 

ampere-hour thresholds. In addition, facilities would be required to keep records 

documenting that the proposed housekeeping requirements are met. 

 13. Proposed section 93102.13--Reporting

Reporting requirements were previously contained in subsection (i). Minor changes are 

proposed to subsections (a) through (d) of section 93102.13, Reporting. These changes 

would clarify the information to be reported or specify when reports are to be submitted to 

the permitting agency. The staff is proposing to modify subsection (e) to identify the 

information that must be submitted to the permitting agency for existing facilities using 

trivalent chromium and for new facilities using the trivalent chromium process. 

14. Proposed section 93102.14--Procedure for Establishing Alternative 

Requirements

Procedures for establishing alternative requirements were previously contained in 

subsection (k). Minor modifications are proposed in subsections (a) through (e) of section 

93102.14, Procedure for Establishing Alternative Requirements. In subsection (f), we are 

proposing that waivers obtained from U.S. EPA for alternative compliance with the 

emission limits will no longer be valid after the date of the requirements in 

section 93102.4(b) become effective for a particular facility. This modification is 

necessary to ensure all facilities meet the new requirements. We are also proposing that 

ARB would have to concur on any waivers associated with alternatives to compliance with 

section 93102.4, Requirements for Existing, Modified, and New Hexavalent Chromium 

Plating and Chromic Acid Anodizing Facilities. 

15. Proposed section 93102.15--Requirements Related to Chromium 

Plating or Chromic Acid Anodizing Kits

Staff is proposing requirements related to chromium plating kits. We are aware that these 

kits are currently offered for sale over the Internet. Because no restrictions exist on who 
Chapter IX Page 96 

may buy these kits, they may be sold or supplied to a person that is not trained or aware 

of the hazards associated with chromium plating or chromic acid anodizing. These kits 

also could be a source of uncontrolled hexavalent chromium emissions. This could lead 

to unacceptable exposures for the individual performing the chromium plating or chromic 

acid anodizing, or for near-by sensitive receptors. 

Because of these hazards, staff is proposing that these chromium plating or chromic acid 

anodizing kits could not be sold, supplied, offered for sale, or manufactured for sale in 

California. However, this provision would not apply if the kit was sold to the owner or 

operator of a permitted chromium plating or chromic acid anodizing facility. 

These kits also could not be used unless the kit is used at a permitted chromium plating 

or chromic acid anodizing facility that is in full compliance with the ATCM. 

We are also proposing that for the purposes of these provisions a “chromium 

electroplating or chromic acid anodizing kit” means chemicals and associated equipment 

for conducting chromium electroplating or chromic acid anodizing, including, but not 

limited to, internal and external tank components. 

 16. Proposed section 93102.16--Appendices

Staff is proposing that the Appendices to the Chromium Plating ATCM be contained 

within a new section, 93102.16. There are eight appendices. Most of these have been 

part of the Chromium Plating ATCM since 1998. Only the Appendices proposed for 

modification or addition are described. Appendix 1, Content of Performance Test 

Reports, is proposed for modification to indicate that test results must be provided in 

milligrams/ampere-hour. 

Appendices 2 and 3, Content of Initial Compliance Status Reports, and Content of 

Ongoing Compliance Status Reports, respectively, are being modified to ensure that the 

permitting agency has all of the necessary information to ensure facilities are complying 

with all of the newly proposed provisions and requirements. 

We are proposing to add a requirement to Appendix 4, Notification of Construction 

Reports, to ensure that any new facility is complying with the provisions for new facilities 

in section 93102.4(d), such as the separation requirements. 

We are proposing to add Appendix 7, Alternative Requirements for Enclosed Hexavalent 

Chromium Electroplating Facilities- Mass Emission Rate Calculation Procedure. The 

calculation method shown in the appendix is used to demonstrate compliance with the 

alternative emission limit for enclosed tanks specified in subsection 93102.6(b)(1)(C). 

We are also proposing to add Appendix 8, Surface Tension Procedure for a 

Stalagmometer. This appendix outlines a method to be followed to ensure accurate and 

consistent measurement of surface tension with a stalagmometer. 

 
Chapter IX Page 97 

17. When the Proposed Amendments Become Legally Effective

In addition, we would like to clarify that the proposed amendments to the ATCM do not 

impose retroactive requirements on chromium plating and anodizing facilities. California 

law is clear that the proposed amendments to the ATCM cannot become legally effective 

until it is adopted by the ARB and is approved by the Office of Administrative Law. Until 

then, chromium plating and chromic acid anodizing facilities are not required to comply 

with any requirement specified in the amended ATCM, unless an air district independently 

imposes the same or similar requirement pursuant to its own local rules or permitting 

authority. 

C. Basis for the Proposed Amendments 

The proposed amendments to the Chromium Plating ATCM are based on our 

reevaluation of BACT for reducing hexavalent chromium emissions from chromium plating 

and chromic acid anodizing facilities, in consideration of health risk and cost. In 

reevaluating BACT, we analyzed information from ARB’s 2003 chromium plating and 

chromic acid anodizing facility survey, available source test data, and data from the 

emissions testing program. 

As a basis for the proposal, staff conducted the HRA to determine estimated cancer risks 

in a manner which is very health protective in estimating cancer risks for a range of 

reasonably foreseeable exposure scenarios. Staff believes this health protective 

approach is necessary due to the very high potency and resultant serious health hazards 

associated with exposure to hexavalent chromium emissions. 

Based on the information collected, the health protective analyses conducted, and 

discussions with air districts, industry, and control equipment manufacturers, we 

determined that reliable control devices are readily available and widely used. Further, 

the application of BACT, as proposed by staff, will result in potential cancer risk levels 

being reduced to no more than one per one million people for 162 facilities (about 75 

percent). An additional 41 facilities (about 20 percent), would have estimated cancer risk 

of no more than ten per million exposed people. Moreover, only six facilities would have 

a remaining cancer risk greater than 25 per million exposed people. Staff’s proposal to 

require a site specific analysis, for review by the air districts, could result in further cancer 

risk reduction from these facilities. Overall 92 percent of the facilities would have cancer 

risk of no more than ten per million exposed people. In addition, the proposed 

amendments would ensure that the chronic hazard indices for all facilities would not 

exceed one. 

D. Alternatives to the Proposed Amendments 

California Government Code section 11346.2 requires the ARB to consider and evaluate 

reasonable alternatives to the proposed amendments to the ATCM and to provide 

reasons for rejecting these alternatives. Staff considered the following alternatives to the 

proposed amendments to the ATCM: 
Chapter IX Page 98 

1. Alternative 1: Require Decorative Chromium Plating Facilities 

 to Use the Trivalent Chromium Plating Process

One alternative to the staff’s proposal would be to require the use of the trivalent 

chromium plating process for all decorative chromium plating facilities. The process is 

already in use successfully in ten businesses (six facilities only conduct trivalent 

chromium plating and four facilities conduct both trivalent and hexavalent chromium 

plating) in California. Requiring all decorative chromium facilities to use the trivalent 

chromium process would eliminate the remaining cancer risk from the hexavalent 

chromium emissions from decorative chromium plating facilities. In fact, the switch to the 

trivalent chromium process could be more cost effective than the staff’s proposal, which 

would require installation of BACT (HEPA add-on air pollution control device). As 

estimated, installation and annual operating costs for a HEPA system are estimated at 

about $89,000 and $33,500 respectively. Our cost estimate for converting to trivalent 

chromium includes a one-time cost of about $41,500 and ongoing costs of $23,000. 

Under the staff’s proposal, there will be residual cancer risk. However, 162 facilities 

would have estimated cancer risks of one or less per million exposed people after 

adoption of the staff’s proposal. Overall, 92 percent of facilities would have cancer risk of 

less than ten per million exposed people. 

Staff has evaluated the trivalent chromium process and has determined that it is not a 

universal replacement for all decorative chromium plating applications. Also, use of the 

trivalent chromium process would create business competitiveness issues between 

California businesses and those in other States, and between California businesses and 

those off-shore. Therefore, staff has determined this is not a technologically feasible 

alternative. 

Nevertheless, businesses may make the decision to convert to the trivalent chromium 

process, if it is a viable option for their application. 

2. Alternative 2: Require HEPA, or the Equivalent, Add-On 

 Air Pollution Control Device for All Facilities

Another alternative would be to require installation of HEPA, or equivalent, add-on air 

pollution control devices for all facilities. This technology is the most effective option. 

Implementation of this proposal would reduce the remaining cancer risk from about 

48 facilities that presently have throughput below 20,000 annual ampere-hours. Staff 

chose not to pursue this alternative. The staff’s proposal represents a balance between 

health risk and cost. For these facilities, chemical fume suppressants represent BACT. 

Adoption of the staff’s proposal will result in these facilities having estimated cancer risks 

below one per million people. This alternative would result in no appreciable additional 

benefit and would add additional equipment costs of over $4.0 million. Individual 

businesses would have annual costs of about $46,000. About half of these facilities are 

small businesses with annual revenue of less than $1,000,000. 
Chapter IX Page 99 

 3. Alternative 3: Adopt the Provisions of Rule 1469 Statewide

Industry representatives have asked staff to evaluate the adoption of SCAQMD 

Rule 1469 statewide. Rule 1469, Control of Hexavalent Chromium Emissions from 

Chrome Plating and Chromic Acid Anodizing Operations, is now in full effect in the 

SCAQMD. Rule 1469 requires hexavalent chromium facilities located within 

25 meters from a sensitive receptor or within 100 meters from a school to reduce 

hexavalent chromium emissions such that the residential cancer risk will be no more than 

ten chances per million people. The rule also requires facilities located greater than 

25 meters from a sensitive receptor or 100 meters from a school to reduce emissions 

such that off-site worker cancer risk would be no more than 25 chances per million 

people. 

Staff has evaluated this alternative and has found it does not provide the level of 

protection that would be achieved through adoption of the staff’s proposal. This is 

because BACT is not required for all facilities. By using off-site worker scenarios to 

calculate cancer risk, rather than residential, the risk to people and children living near the 

facility is underestimated by one-third. This means that estimated cancer risk for 

residents is 33 per million people exposed, rather than 25 per million people exposed. 

ARB could not use this scenario because it does not follow standard risk assessment 

methodologies developed by OEHHA and employed by ARB. 

If Rule 1469 were implemented statewide, 75 percent of facilities would have estimated 

cancer risk of less than ten per million exposed people. This offers very little benefit over 

the baseline in which 71 percent of facilities were found to have estimated cancer risk of 

ten per million exposed people. The staff’s proposal would result in 92 percent of facilities 

having estimated cancer risk of less than ten per million exposed people. In addition, if 

Rule 1469 were adopted statewide, eight percent of facilities would have cancer risk of 

over 25 per million exposed people. Two facilities’ risk would exceed 100 per million 

exposed people. This is not health protective given the availability of BACT. If the staff’s 

proposal were adopted, no facilities would have cancer risks over 100 per million exposed 

people. A comparison of the benefits of adopting Rule 1469 statewide and the benefits of 

the staff’s proposal as shown in Figure IX-1. 

Adoption of Rule 1469 statewide would, however, result in cost savings over the staff’s 

proposal. Equipment costs would be about $600,000 because only seven additional 

facilities would need to install add-on air pollution control devices. 

 4. Alternative 4: Require No Further Control

Alternative 4 would be to require no additional control beyond what the existing ATCM, in 

combination with implementation of Rule 1469 in the SCAQMD, has achieved. This 

would be equivalent to the 2005 baseline cancer risk. This would result in allowing the 

maximum incremental cancer risks from some facilities to exceed 100 per million people 

and for 29 percent of facilities to have cancer risk in excess of ten per million people. 

Only 41 percent of facilities would have estimated cancer risk below one per million 

exposed people. Requiring no further control would, of course, result in cost savings 
Chapter IX Page 100 

because the staff’s proposal is estimated to cost $14.2 million dollars. Of this amount, 

about $9.6 million would be related to purchasing HEPA filtering add-on air pollution 

control devices. 

Staff does not believe the status quo is protective of public health especially considering 

that 43 percent of facilities are located within 100 meters of a sensitive receptor. Our goal 

is to achieve the maximum feasible health protection using the most effective controls. 

This is especially important when people are living, learning, working, or playing near 

chromium plating and chromic acid anodizing facilities. Thus, staff did not choose 

Alternative 4. 

 5. Summary

Table IX-5 compares alternatives three and four with the staff’s proposal. Alternatives 

one and two are not presented. Alternative one is not technologically feasible. 

Alternative two essentially offers no benefit beyond the staff’s proposal. 

Table IX-5. Adoption of Staff’s Proposal Offers the Greatest Reduction in Significant 

Community Cancer Risk 

 Number of Facilities by Cancer Risk 

<1 

per million 

>1 <10 

per million 

>10 <100 

per million 

>100 

per million 

Staff Proposal 162 41 17 0 

Rule 1469 

Statewide 98 67 53 2 

Baseline 90 67 57 6 

Table IX-5 shows that the staff’s proposal offers the best health protection. As shown, 

adopting the provisions of SCAQMD Rule 1469 statewide would result in 98 facilities 

(about 45 percent) with remaining cancer risk of no more than one per million exposed 

persons. This represents an additional 8 facilities compared to the baseline. Adoption of 

the staff’s proposal would reduce the estimated cancer risk for 162 facilities (about 

74 percent) to no more than one per million exposed persons. 

6. Conclusion

We evaluated each of the alternatives and determined that the alternatives did not meet 

the objective of Health and Safety Code section 39666 to reduce emissions to the lowest 

level achievable through the application of BACT, or a more effective control method, in 

consideration of cost, health risk, and environmental impacts. 
Chapter IX Page 101 

E. Recommendation 

Based on the forgoing, staff recommends that the Board adopt the proposed 

amendments to the Chromium Plating ATCM (Appendix A). Requiring BACT for all 

facilities provides the greatest reductions in significant community cancer risk. The staff’s 

proposal, compared to the 2005 baseline, would result in up to an 85 percent reduction in 

estimated cancer risk for individual facilities. Staff predicts the proposal would reduce 

162 facilities’ (about 74 percent) cancer risk to no more than one per million exposed 

people, and reduce cancer risk to no more than ten per million for over 92 percent of 

facilities. The proposal would also directly benefit low income and ethnically diverse 

communities that have been disproportionately impacted by emissions from chromium 

plating and chromic acid anodizing facilities. 
Chapter IX Page 102 

REFERENCES: 

SCAQMD, 2004. South Coast Air Quality Management District. Certified List of Fume 

Suppressants for Facilities Performing Chrome Plating and Chromic Acid Anodizing 

Operations. 2004 (http://www.aqmd.gov/prdas/ChromePlating/ChromePlating.htm) 

U.S. EPA, 2004. U.S. Environmental Protection Agency. 40 CFR Part 63: “National 

Emission Standards for Chromium Emissions From Hard and Decorative Chromium 

Electroplating and Chromium Anodizing Tanks”. 2004. 
Chapter X Page 103 

X. Economic Impacts 

ARB staff has evaluated the estimated costs and economic impacts associated with 

implementation of the proposed amendments to the Chromium Plating ATCM. This 

Chapter summarizes the results of our findings. The expected first year estimated costs, 

capital costs and annual recurring costs that would be expended to comply with the 

proposed amendments are described. Staff has conducted a conservative analysis of 

potential costs to be incurred. We have estimated that all facilities needing to 

demonstrate compliance with the 0.0015 milligrams/ampere-hour limit would install a 

HEPA add-on air pollution control device. This may not be the case. Some facilities may 

be able to demonstrate compliance with alternative, cheaper methods. The costs and 

associated economic impacts are given for private companies and California 

governmental agencies. 

A. Summary of the Economic Impacts 

The proposed amendments to the Chromium Plating ATCM are not expected to have a 

significant adverse impact on the profitability of most owners or operators of chromium 

plating and chromic acid anodizing facilities in California. However, staff has determined 

that costs for some individual businesses are expected to be significant and would 

adversely impact their profitability. The effect of compliance costs on profitability impacts 

were estimated by calculating the decline in the return on owner’s equity (ROE). A 

decline in ROE of 10 percent or more indicates a significant adverse impact. The 

proposed amendments to the ATCM are expected to result in an average ROE decline of 

nine percent which is not considered to be a significant impact on the profitability of most 

affected businesses. However, the ROE for some individual businesses exceeds ten 

percent. We estimate that businesses’ profitability impacts range from less than one 

percent to 41 percent. 

When considering the entire industry, we expect the proposed amendments to have no 

significant impact on employment; business creation, elimination or expansion; or 

business competitiveness in California. However, some individual businesses, including 

small businesses, could be significantly impacted, which could result in business closures 

and lost jobs. We expect no significant adverse fiscal impacts on any local or State 

agencies. 

Of the 226 facilities affected by the proposed amendments to the ATCM, up to 

89 facility owners would be required to expend significant capital to meet the 

requirements. Some of these operators may have difficulty securing the required capital 

to finance the cost of the add-on air pollution control devices that would be required for 

compliance with the proposed amendments to the ATCM. However, in 2005, the 

Governor signed legislation to establish a loan guarantee program for decorative 

chromium plating operations to purchase pollution control equipment. The program is 

administered by the Business, Transportation, and Housing Agency. The program 

provides loan guarantees of up to $100,000 to owners of decorative chromium plating 

small businesses that may not be able to qualify for a conventional loan. In July of this 
Chapter X Page 104 

year, the Governor signed into law amendments to the loan guarantee program. The loan 

guarantee program is now available for all metal plating facilities. 

During the first year, all facilities would have compliance costs. Costs would vary 

depending on the extent an individual business was already in compliance with the 

proposed amendments. About 40 percent of facilities are already controlled with HEPA 

filtration systems, or equivalent; they would incur no capital costs. Another 20 percent of 

facilities would use chemical fume suppressants as sole control. Therefore, these 

facilities compliance costs will be low, as well. Compliance costs for trivalent chromium 

plating facilities would also be low. The proposed amendments would only require these 

facilities to file an initial compliance status report. 

We estimate that costs in the first year would range from $450 to $217,000 with an 

average cost of $23,000. Median cost would be $8,500. In subsequent years, costs 

would range from essentially no cost to $217,000 with an average cost of $53,000. 

Median cost in subsequent years would be $46,000. After the first year, 60 percent of the 

facilities would have no additional compliance costs. Costs for all facilities include 

completion of an initial compliance status report. Other costs incurred by some, but not 

all facilities, include permit fees, performance testing, site specific analyses, 

housekeeping costs, capital equipment costs (amortized), and ongoing (recurring) costs. 

The assumptions from which these costs are estimated as described below. 

B. Economic Impact Analysis 

1. Legal Requirements

Section 11346.3 of the Government Code requires State agencies to assess the potential 

for adverse economic impacts on California business enterprises and individuals when 

proposing to adopt or amend any administrative regulation. The assessment must 

include a consideration of the impact of the proposed regulation on California's jobs, 

business expansion, elimination or creation, and the ability of California businesses to 

compete with businesses in other states. 

In addition, State agencies are required to estimate the cost or savings to any State or 

local agency and school district in accordance with instructions adopted by the 

Department of Finance. The estimate shall include any non-discretionary cost or savings 

to local agencies and the cost or savings in federal funding to the State. 

Health and Safety Code section 57005 requires the ARB to perform an economic impact 

analysis of submitted alternatives to a proposed regulation before adopting any major 

regulation. The proposed amendments to the Chromium Plating ATCM are considered to 

be a “major regulation”, because the estimated cost to California business enterprises 

exceeds $10 million in the first year. 

 
Chapter X Page 105 

2. Affected Businesses

Any business conducting chromium plating, chromic acid anodizing, or business selling 

chromium plating kits to non-permitted facilities would be affected by the proposed 

amendments to the ATCM. Also potentially affected are businesses that are customers of 

chromium plating or chromic acid anodizing facilities, such as the aerospace and 

automotive industries. The focus of this analysis, however, will be chromium plating and 

chromic acid anodizing facilities because these businesses would be most affected by the 

proposed amendments to the ATCM. 

The affected businesses generally fall under a Standard Industrial Classification (SIC) 

code of 34, Fabricated Metal Industry, and more specifically, SIC 3471, Plating and 

Polishing, or North American Industry Classification System (NAICS) 332813. 

 3. Potential Impacts on Profitability for Affected Businesses

The approach used in evaluating the potential economic impact of the proposed 

amendments to the ATCM on California businesses is as follows: 

• All affected facilities are identified from responses to the ARB's 2003 Chromium 

Plating and Anodizing Facility Survey. 

• Financial data and net profit data are obtained for a typical business engaged in 

plating and polishing businesses from Dun’s Financial Profile; SIC 3471 Industry 

Profiles (D&B, 2005) and Dun and Bradstreet Business Information Report. (D&B, 

2006) 

• The annual cost of compliance is estimated for the businesses that are affected by the 

proposed amendments to the ATCM. 

• The annual cost of compliance for each business is adjusted for both federal and state 

taxes. It is assumed affected businesses are subject to federal and State tax rates of 

 35 percent and 9.3 percent, respectively. 

• These adjusted costs are subtracted from net profit data and the results are used to 

recalculate the ROE. 

• The resulting ROE is then compared with the ROE before the subtraction of the 

adjusted costs to determine the impact on the profitability of the businesses. A 

reduction of more than 10 percent in profitability is considered to indicate a potential 

for significant adverse economic impacts. This threshold is consistent with the 

thresholds used by the U.S. EPA and ARB in previous regulations. 

• Affected businesses absorb the costs of the proposed amendments to the ATCM 

instead of increasing the prices of their products or lowering their costs of doing 

business through cost-cutting measures. 

All of the chromium plating and chromic acid anodizing businesses affected by these 

proposed amendments are California businesses. These businesses are affected to the 

extent that implementation of the proposed amendments reduces their profitability. Using 

ROE to measure profitability, we estimate the decline in ROE for most affected 
Chapter X Page 106 

businesses would be less than ten percent based on 2002-2004 financial data. This is 

based on an average compliance cost for all facilities of $23,000. This does not represent 

a noticeable decline in the profitability of most affected businesses. 

However, for the 89 businesses that would likely need to install or upgrade add-on air 

pollution control devices, the estimated decline in profitability ranges from 3 to 41 percent. 

The average estimated compliance costs for these facilities is $53,000. 

Of the 89 facilities, 28 small businesses may need to install add-on air pollution control 

devices. This could result in a potential significant adverse cost impact. These 

businesses’ profitability could decline by 33 percent in order to comply with the proposed 

amendments. Some marginal businesses would likely face a difficult business decision 

as to whether to continue operating the chromium plating portion of their operation. 

However, this cost analysis is based on the assumption that these small businesses 

would have to install add-on air pollution control devices. Some of these businesses may 

be able to demonstrate compliance without the use of an add-on air pollution control 

device. Others may decide to cease chromium plating, but retain other aspects of their 

operations and remain viable. In these instances, the ROE estimated here would be 

much lower. Some of these businesses may also qualify for a loan guarantees of up to 

$100,000 to purchase pollution control equipment. 

The remaining 137 businesses would have average compliance costs of about $4,000. 

The decline in profitability for these businesses is not considered to be significant. The 

change in ROE ranges from less than one percent to nine percent. 

 4. Assumptions for Facility Cost Estimates

Seventy-five percent of the facilities are located in the SCAQMD. These facilities have 

already complied with Rule 1469 and are familiar with how the air district estimated costs 

for compliance with that rule. To allow for a comparison ARB staff generally used the 

SCAQMD’s cost methodology, except that costs were grown from 2003 to 2006 dollars at 

a rate of 5 percent (factor of 1.158). Using this factor provides for a ‘worst case’ cost 

estimate because the inflation rate has been about three percent over this period of time 

(CPI, 2006). The costs estimated for each compliance requirement are summarized 

below in Tables X-1 and X-2. In addition, chemical fume suppressant cost was estimated 

at $185/gallon at a use rate of 1.98x10-6 gallons/ampere-hour. 

 

Table X-1. Estimated Compliance Costs (Other than Those for Add-On Air 

 Pollution Control Devices)** 

Initial 

Compliance

Plan 

Drip Trays Plastic Strip 

Curtains

Permit fee * Source 

Test 

Site 

Specific 

Analysis 

$450 2@ $350 $1,138 $700/$2,232 $7,335 $11,500 

* Permit fee of $2,232 for initial HEPA permit (cost estimate from ARB’s Thermal Spraying Report). 

** Costs are rounded. 
Chapter X Page 107 

Table X-2 displays the cost estimates used to estimate costs associated with hexavalent 

chromium add-on air pollution control devices. 

Table X-2. Costs for HEPA Add-on Air Pollution Control Devices 

System size Based on 

Fan Size Freight Equipment Installation Recurring 

Small 

(5,000 Cubic Feet per 

Minute (CFM)) 

$1,580 $33,047 $54,129 $33,513 

Medium 

(10,000 CFM) $2,328 $48,705 $79,313 $39,850 

Large (20,000 CFM) $3,843 $80,396 $129,882 $57,570 

For consistency, ARB staff calculated the cost of add-on air pollution controls as per the 

SCAQMD method. It was assumed that each tank at a facility is 36 square feet and is 

ventilated at 150 CFM per square foot. One tank, would require 5,400 CFM to be 

properly ventilated. The number of tanks at a facility was then multiplied by 5,400 to 

arrive at the total amount of ventilation required (SCAQMD, 2003a and SCAQMD, 

2003b). 

 For example: 6 tanks @ 36 square feet X 5,400 CFM = 32,400 total CFM 

In this example, it is assumed the facility would need to purchase one 5,000 CFM system 

@ $88,756, one 10,000, system @ $130,346, and one 20,000 CFM system @ $214,121. 

The total cost would be $433,223. In like fashion, recurring costs would be $130,933. 

When actual tank numbers were known, this information was used to estimate cost. 

When this information was not available, staff estimated the number of tanks needing 

ventilation based on facilities with similar ampere-hours where the number of tanks was 

known. The size of the system does not necessarily relate to throughput. An 

intermediate-sized facility (no more than 200,000 ampere-hours) may have multiple tanks 

requiring ventilation, such that a larger system 10,000 CFM system is needed. Other very 

large throughput facilities may only have one tank requiring ventilation. In this case, the 

larger facility would have cheaper compliance costs as only a 5,000 CFM system may be 

needed. However, staff has estimated that of the 89 facilities required to install HEPA 

systems, 80 out of 89 would be 5,000 CFM systems. 

We annualized non-recurring fixed costs using the Capital Recovery Method. Using this 

method, we multiplied the non-recurring fixed costs by the Capital Recovery Factor (CRF) 

to convert these costs into equal annual payments over a ten year project horizon at a 

discount rate of five percent. The Capital Recovery Method for annualizing fixed costs is 

recommended by the California Environmental Protection Agency (Cal/EPA) (Cal/EPA, 

1996), and is consistent with the methodology used in previous cost analyses for ARB 

regulations (ARB, 2000). 
Chapter X Page 108 

The CRF is calculated as follows: 

 CRF

i i

i

n

= n

+

+ −

( )

( )

1

1 1

 

where, 

 CRF = Capital Recovery Factor 

 i = discount interest rate (assumed to be 5 percent) 

 n = project horizon or useful life of equipment 

All costs of the add-on air pollution control devices were annualized over 10 years. These 

values are based on a conservative estimate of the expected lifetime of the equipment. 

The total annualized cost was obtained by adding the annual recurring costs to the 

annualized fixed costs derived by the Capital Recovery Method. 

Capital costs include the cost of the add-on air pollution control device, installation, 

freight, source test, and instrumentation. 

Recurring costs include replacement filters, disposal of filters as hazardous waste, 

electrical usage, labor, property tax, insurance, and reporting costs. 

 

5. Potential Economic Impacts for Individual Chromium Plating and 

 Anodizing Facilities

From our industry survey we have identified 226 chromium plating and chromic acid 

anodizing facilities in California. Of these businesses, two are federal government 

facilities, the U.S. Naval Aviation Depot, in the SDCAPCD, and the United States Mint in 

the BAAQMD. 

We estimate that 71 of the affected businesses are small businesses with gross annual 

revenue of less than $1.0 million (U.S. EPA, 1995a). Of these, 28 businesses would 

likely incur costs associated with purchase and operation of add-on air pollution control 

devices. 

In terms of estimating compliance costs, facilities can be divided into 4 groups: trivalent 

chromium plating facilities; hexavalent chromium plating and chromic acid anodizing 

facilities with throughput of less than or equal to 20,000 annual ampere-hours; hexavalent 

chromium plating and chromic acid anodizing facilities with throughput of more than 

20,000 but less than or equal to 200,000 annual ampere-hours; and hexavalent chromium 

plating and chromic acid anodizing facilities with throughput of more than 200,000 annual 

ampere-hours. There are also hexavalent chromium plating and chromic acid anodizing 

facilities with throughput of more than 20,000 that are already in substantial compliance 

with the proposal. Costs for these facilities will be estimated separately from those 

needing to expend significant capital to comply. 
Chapter X Page 109 

 a. Trivalent Chromium Plating Facilities

Six facilities conduct only trivalent chromium plating. These facilities would incur costs 

associated with submitting an initial compliance status report. This cost has been 

estimated at $450 per facility. Beyond this one-time cost, compliance with the proposed 

amendments would result in no additional cost for these facilities. 

b. Hexavalent Chromium Plating and Chromic Acid Anodizing Facilities 

with Throughput of Less Than or Equal to 20,000 Annual AmpereHours

Forty-eight facilities have been identified with throughput of less than or equal to 20,000 

annual ampere-hours. Under the proposed amendments these facilities would be allowed 

to control hexavalent chromium emissions by reducing surface tension of the 

plating/anodizing bath by using specified chemical fume suppressants. Compliance costs 

for these facilities are estimated to average about $2,000. The costs were estimated as 

described below. 

Based on 2003 calendar year data, only ten of these 48 facilities were not using the 

specified chemical fume suppressants. Costs for these ten facilities to begin using 

specified chemical fume suppressants would result in no significant cost increase. All 

48 of these facilities however, would need to complete an initial compliance status report 

estimated to cost $450. It is also assumed that these facilities would have permit renewal 

fees of $700. For facilities with buffing, grinding or polishing operations we estimated 

costs associated with purchase of plastic strip curtains at $1,100. Costs for purchase of 

drip trays for facilities with automated lines were estimated to cost $700. Thus, costs for 

these facilities range from $1,150 to $2,600, with average compliance costs of $2,000. 

After the first year, 38 of these facilities would have no additional compliance costs 

beyond housekeeping and recordkeeping. Ten facilities would have annual recurring 

costs, but they are near zero. 

c. Hexavalent Chromium Plating and Chromic Acid Anodizing Facilities 

with Throughput of More Than 20,000 but Less Than or Equal to 

200,000 Annual Ampere-Hours

Sixty facilities have been identified with more than 20,000 but less than or equal to 

200,000 annual ampere-hours. Of these, 45 facilities would need to take actions to 

demonstrate compliance with the emission limit of 0.0015 milligrams/ampere-hour; the 

other 15 facilities are already in substantial compliance. Generally, to meet the 

0.0015 milligrams/ampere-hour limit requires use of a HEPA add-on air pollution control 

device. However, the requirement would be phased in based on throughput and 

proximity to sensitive receptors. [The other 15 facilities’ costs are estimated as described 

in part e., below.] Total capital costs for these facilities are estimated to be about 

$4.0 million. Total annualized costs (amortized plus recurring costs) are estimated to be 

$2.1 million. The costs were estimated as described below. 
Chapter X Page 110 

Twenty-eight of these facilities are located within 100 meters of a sensitive receptor and 

would be required to demonstrate compliance within two years. The other 17 facilities 

would have five years to demonstrate compliance with the emission limit because they do 

not have sensitive receptors located within 100 meters. Some of these 45 facilities may 

be able to demonstrate compliance with the emission limit without installation of a HEPA 

add-on air pollution control device. However, most are expected to need to install a 

HEPA add-on air pollution control device to meet the 0.0015 milligrams/ampere-hour limit. 

Costs were estimated based on installation of a HEPA add-on air pollution control device 

for all of these facilities. 

All of these facilities would need to complete an initial compliance status report estimated 

to cost $450. It is also assumed that these facilities would have permit fees associated 

with installation a HEPA add-on air pollution control device. This cost is estimated to be 

$2,200. Ongoing permit renewal fees are estimated at $700. For facilities with buffing, 

grinding or polishing operations we estimated costs associated with purchase of plastic 

strip curtains at $1,100. Costs for purchase of drip trays for facilities with automated lines 

were estimated to cost $700. Performance tests would be required of all facilities, which 

is included in the cost of purchasing and installing a HEPA add-on air pollution control 

device. 

The cost to purchase an add-on air pollution control device is estimated to be $89,000 in 

initial capital costs (including installation, source testing, and freight). For these facilities, 

we amortized the costs of purchasing the add-on air pollution control devices over ten 

years. We also amortized the costs for permit fees, and purchase of plastic strip curtains 

and/or drip trays when required. Total costs to be amortized are estimated to be $92,000. 

This equates to an annualized capital cost of about $12,000 (in 2006 dollars) over the life 

of the equipment. 

Annual recurring costs associated with equipment maintenance and ongoing permit fee 

renewals are estimated at $34,000. Combining these annual costs with amortized costs 

results in an annual cost of about $46,000 for purchase, installation, reports, fees, 

analyses, and maintenance of the equipment. 

d. Hexavalent Chromium Plating and Chromic Acid Anodizing Facilities 

with Throughput of More Than 200,000 Annual Ampere-Hours 

One hundred twelve facilities have been identified with more than 200,000 annual 

ampere-hours. Of these, 44 facilities would need to take actions to demonstrate 

compliance with the emission limit of 0.0015 milligrams/ampere-hour, as measured after 

an add-on air pollution control device. Generally, this requires use of a HEPA add-on air 

pollution control device. Costs were estimated for these facilities based on installation of 

a HEPA add-on air pollution control device. These facilities would be required to 

demonstrate compliance within two years. [The other 68 facilities’ costs are estimated as 

described in part e., below.] Total capital costs for 44 facilities are estimated to be $5.6 

million. Total annualized costs (amortized plus recurring costs) are estimated to be $2.7 

million. The costs were estimated as described below. 
Chapter X Page 111 

All of these facilities would need to complete an initial compliance status report estimated 

to cost $450. It is also assumed that these facilities would have permit fees associated 

with installation a HEPA add-on air pollution control device. This cost is estimated to be 

$2,200. Ongoing permit renewal fees are estimated at $700. For facilities with buffing, 

grinding or polishing operations we estimated costs associated with purchase of plastic 

strip curtains at $1,100. Costs for purchase of drip trays for facilities with automated lines 

were estimated to cost $700. Performance tests would be required of all facilities, which 

is included in the cost of purchasing and installing a HEPA add-on air pollution control 

device. After meeting the 0.0015 milligrams/ampere-hour limits, one facility would be 

required to conduct an additional assessment to determine if further risk reduction was 

needed. Cost for site specific analysis is estimated to cost $11,500. 

The costs to purchase add-on air pollution control devices are estimated to range from 

$89,000 to about $500,000 in initial capital costs (including installation, source testing, 

and freight). Average capital cost is about $130,000. For these facilities, we amortized 

the costs of purchasing the add-on air pollution control devices over ten years. We also 

amortized the costs for permit fees, and purchase of plastic strip curtains and/or drip trays 

when required. Total costs to be amortized range from about $90,000 to $500,000. This 

equates to an annualized capital cost of about $12,000 to $68,000 (in 2006 dollars) over 

the life of the equipment. 

Annual recurring costs associated with equipment maintenance and ongoing permit fee 

renewals are estimated to range from $34,000 to $150,000, with an average of about 

$43,000. Combining these annual costs with amortized costs results in an annual cost of 

about $46,000 to $217,000 for purchase, installation, reports, fees, analyses, and 

maintenance of the equipment. The mean cost would be about $61,000. 

e. Hexavalent Chromium Plating and Chromic Acid Anodizing Facilities 

with Throughput of More Than 20,000 Annual Ampere-Hours Already 

in Substantial Compliance with the Proposal

Eighty-three facilities have been identified with throughput of more than 20,000 annual 

ampere-hours that already meet the emission limit. These facilities would incur 

compliance costs in the first year only. The average compliance cost for these facilities is 

about $5,500. The costs for these facilities were estimated as described below. 

All of these facilities would need to complete an initial compliance status report estimated 

to cost $450. It is also assumed that these facilities would have permit renewal fees of 

$700. For facilities with buffing, grinding or polishing operations we estimated costs 

associated with purchase of plastic strip curtains at $1,100. Costs for purchase of drip 

trays for facilities with automated lines were estimated to cost $700. Performance tests 

would be required of 31 facilities with an estimated cost of $7,500 each. Based on 2003 

data, five facilities would be required to conduct an additional assessment to determine if 

further risk reduction was needed. Cost for this site specific analysis is estimated to cost 

$11,500. Thus, costs for these facilities range from $1,150 to $21,000, with average 
Chapter X Page 112 

compliance costs of about $5,000. Beyond the first year, these facilities would have no 

additional compliance costs beyond housekeeping and recordkeeping. 

6. Potential Impact on Manufacturers and Suppliers of Chromium Plating 

and Chromic Acid Anodizing Equipment and Chemicals

We do not expect manufacturers of chromium plating and chromic acid anodizing 

materials to incur any costs. However, the staff’s proposal to prohibit sales of chromium 

plating kits to non-permitted facilities may result in lost revenue for these businesses. 

The proposed amendments would potentially impact the chemical manufacturers in a 

positive way through increased sale of chemical fume suppressants. Add-on air pollution 

control device manufacturers, as well as the metal fabricating industry, would also benefit 

from the proposed amendments as controls and ductwork for ventilation systems are 

purchased. 

 7. Potential Impact on Consumers

The potential impact of the proposed amendments to the ATCM on consumers depends 

upon the extent to which affected businesses are able to pass on the increased cost to 

consumers in terms of higher prices for their goods and services. If all costs are passed 

onto the consumers, we expect the cost per ampere-hour to increase by between $0.01 

to $2.21 per ampere-hour. These costs are estimated based on facilities that would have 

to install add-on air pollution control devices. The lower end of this cost would represent 

a large facility, while the upper end cost would represent a small facility. 

To put these costs into perspective consider that chromium plating an automobile bumper 

(a decorative chromium application) requires 10 to 12 ampere-hours (Walker, 2006). 

Using the cost per ampere-hour above, this would mean the increased cost of a bumper 

would be between $0.12 to $26.52. A larger automobile bumper would require 50 

ampere-hours to chromium plate (Walker, 2006). This would mean the increased cost to 

plate a larger bumper would be under a dollar to as much as $110 more. One current 

cost estimate to re-plate a bumper is $400. Because the majority of plating is done at 

larger facilities we anticipate the net impact on consumers to be negligible to minor. 

8. Potential Impact on Employment

Of the 226 affected businesses, 86 percent responded to our survey and provided 

calendar year 2003 employee data. Fifty percent reported employing 25 or fewer people. 

Another 30 percent reported employing between 26 to 100 people. Four businesses 

reported employing 1,000 or more employees. Generally, facilities with large numbers of 

employees have a chromium plating or anodizing process as part of the overall facility’s 

operation. It is likely only a small number of these employees would be dedicated to 

conducting plating or anodizing. An example of this situation would be an aerospace 

company. About 25 facilities that would have substantial compliance costs employ ten or 

fewer people. 
Chapter X Page 113 

We expect the proposed amendments to the ATCM to adversely impact some 

employees. 

 9. Potential Impact on Business Creation, Elimination or 

 Expansion

The proposed amendments to the ATCM would have an impact on the status of some 

California businesses. The compliance costs of the proposed amendments to the ATCM 

are expected to be significant for marginal chromium plating and chromic acid anodizing 

facilities as shown by the estimated impacts on the profitability of some affected 

businesses. The businesses subject to control requirements are expected to pass the 

compliance costs on to their customers, or make a business decision as to whether or not 

to continue operations.

 10. Potential Impact on Business Competitiveness

The proposed amendments to the ATCM will not have a significant, statewide adverse 

impact on the ability of California businesses to compete with businesses in other states, 

although the competitiveness of some individual business would be adversely impacted. 

No other state controls emissions of hexavalent chromium from chromium plating and 

chromic acid anodizing businesses as stringently as does California. Most other states’ 

requirements are limited to those of the federal Chromium Plating NESHAP, which is less 

stringent than the existing ATCM. Therefore, the existing ATCM creates a competitive 

disadvantage for some California businesses because they generally do not have 

compliance costs as high as out-of-state businesses. 

The proposed amendments would make this existing competitive disadvantage worse for 

some individual businesses (i.e., those chromium plating and chromic acid anodizing 

businesses that would have to spend significant amounts of money to comply with the 

amended ATCM). However, approximately 60 percent of the existing businesses are in 

substantial compliance with the requirements that would be established by the proposed 

amendments, and would have to spend very little additional money to comply. The 

proposed amendments would not have a significant adverse impact on the existing 

competitive position of these businesses. In addition, many chromium plating and 

chromic acid anodizing businesses in California compete only with other California 

businesses. The competitive position of these businesses would also not be significantly 

impacted by the proposed amendments. 

 

11. Costs to Public Agencies

Health and Safety Code section 39666 requires that, once the Board adopts the proposed 

amendments, the air districts implement and enforce the ATCM or adopt an equally 

effective or more stringent regulation. Because the air districts will have primary 

responsibility for implementing and enforcing the proposed amendments to the ATCM, we 

evaluated the potential cost to the air districts. We also evaluated the potential cost to 
Chapter X Page 114 

local and State agencies. This section provides the conclusions we reached and the 

basis for those conclusions. 

The chromium plating and anodizing facilities affected by the proposed amendments to 

the ATCM are located in eight air districts, as shown in Table X-3. 

Table X-3. Number of Affected Hexavalent Chromium Plating and Chromic Acid 

Anodizing Facilities by Air District 

Location 

# Affected 

Facilities 

# Facilities 

Installing or 

Upgrading 

Controls 

Percent 

of 

Facilities

Bay Area AQMD 18 12 8 

Feather River AQMD 1 0 <1 

Sacramento Metro AQMD 5 3 <1 

South Coast AQMD 173 60 76 

San Diego APCD 9 2 4 

San Joaquin Valley APCD 17 12 8 

Shasta County APCD 2 0 <1 

Ventura County APCD 1 0 <1 

Total 226 89 

New costs the air districts would incur as a result of the proposed amendments would be 

reviewing initial compliance status reports; reviewing permit modifications for facilities 

adding or upgrading to HEPA, or an equivalent level of control; reviewing source test 

protocols and results; and reviewing site specific analyses, if necessary. The air districts 

already review ongoing compliance status reports and permit renewals. Facilities are 

also regularly inspected. Therefore, we do not expect any additional costs to be incurred 

for performing these functions. We estimate the new costs to air districts resulting from 

the proposed amendments to the ATCM to be approximately $685,000. 

However, air districts can recover these costs through fees charged to the facilities. The 

costs to the air districts can be recovered under the fee provisions authorized by Health 

and Safety Code sections 42311 and 40510. Therefore, the proposed amendments to 

the ATCM would impose no costs on the air districts that would require the State to 

reimburse them pursuant to Section 6 of Article XIIIB of the California Constitution and 

Part 7 (commencing with section 17500), division 4, title 2 of the Government Code. We 

are also aware that some air districts may assess costs differently than how costs were 

estimated for this rulemaking. However, any additional costs are also recoverable from 

fees assessed on facilities within their air district. 

The proposed amendments to the Chromium Plating ATCM would not affect any State 

agency or program other than ARB. Although the air districts will have primary 

responsibility for enforcing the proposed amendments to the ATCM, the ARB may, at the 

request of an air district, provide assistance in the form of technical expertise, legal 

support, or other enforcement support. We estimate that providing assistance to air 
Chapter X Page 115 

districts as they adopt the proposed amendments to the ATCM would require about onequarter person year or $25,000 over the next three fiscal years. Review and approval of 

chemical fume suppressants data to affirm the chemicals meet the 

0.01 milligram/ampere-hour limit would require about two person months each, or 

$17,000. We expect the number of reviews to be small. These costs are absorbable 

within the existing ARB budget. 

We also anticipate no fiscal effect on federal funding of State programs. 

12. Total Cost of the Proposed Amendments to the Airborne Toxic 

 Control Measure

Based on information provided in the ARB’s 2003 Chromium Plating and Chromic Acid 

Anodizing Facility Survey, and applying similar compliance costs to those estimated for 

compliance with SCAQMD Rule 1469 (2003 dollars grown to 2006 dollars at a rate of 

5 percent per year), we estimated the total cost of compliance with the proposed 

amendments to the ATCM. Total capital costs for purchase of add-on air pollution control 

devices are estimated at $9.6 million. Total recurring costs are estimated at $3.6 million. 

An additional $1.0 million in costs are estimated for reports, source testing, permit fees, 

and site specific analyses. In total, costs are estimated to be $14.2 million. 

During the first year, all facilities would have compliance costs. Costs would vary 

depending on the extent an individual business was already in compliance with the 

proposed amendments. We estimate that costs in the first year would range from $450 to 

about $217,000 with an average cost of about $23,000. In subsequent years, costs 

would range from near zero to $217,000, with an average cost of $53,000. Nine facilities 

would have ongoing costs over $50,000. After the first year, 60 percent of the facilities 

would have no additional compliance costs. 
Chapter X Page 116 

REFERENCES

ARB, 2000. Air Resources Board. “Staff Report: Initial Statement of Reasons for 

Proposed Amendments to the Vapor Recovery Certification and Test Procedures for 

Gasoline Loading and Motor Vehicle Gasoline Refueling at Service Stations.” 2000. 

Cal/EPA, 1996. California Environmental Protection Agency. Memorandum from Peter 

M. Rooney, Undersecretary, to Cal/EPA Executive Officers and Directors. “Economic 

Analysis Requirements for the Adoption of Administrative Regulations.” Appendix C 

(“Cal/EPA Guidelines for Evaluation Alternatives to Proposed Major Regulations”). 1996. 

CPI, 2006. InflationData.com. Current Consumer Price Index. 2006 

(http://www.inflationdata.com/inflation/consumer_price_index/currentCPI.asp) 

D&B, 2005. Dun and Bradstreet. Duns Financial Profile - Industry Profile; SIC 3471. 

2005 

D&B, 2006. Dun and Bradstreet. D&B’s Business Information Report – Various 

Businesses. 2006 

SCAQMD, 2003b. South Coast Air Quality Management District. “Draft Socioeconomic 

Assessment for Proposed Amendments to Rule 1469-Hexavalent Chromium Emissions 

from Chrome Plating and Chromic Acid Anodizing Operations and Proposed Rule 1426-

Emissions from Metal Finishing Operations”. 2003 

SCAQMD, 2003a. South Coast Air Quality Management District. “Draft Staff Report for 

Proposed Amended Rule 1469-- Hexavalent Chromium Emissions from Chrome Plating 

and Chromic Acid Anodizing Operations and Proposed Rule 1426- Emissions from Metal 

Finishing Operations.” 2003 

U.S. EPA, 1995a. U.S. Environmental Protection Agency, “EPA Office of Compliance 

Sector Notebook Project – Profile of the Fabricated Metal Products Industry”. 1995 

Walker, 2006. Air Resources Board staff telephone conversation with Howard Walker, 

Walker’s Custom Chrome. 2006
Chapter XI Page 118 

XI. Environmental Impacts 

The main goal of these proposed amendments is to reduce the public’s exposure to 

hexavalent chromium by achieving the maximum reduction in emissions. This is done by 

proposing a phase-in of HEPA filters, or equivalent for the intermediate and large size 

facilities, and use of chemical fume suppressants for very small facilities. The proposed 

amendments are especially designed to reduce exposures when chromium plating and 

chromic acid anodizing facilities are located near where children and people live, learn, 

work, and play. The proposal is also designed to have direct benefit for low income and 

non-white communities that have been disproportionately impacted by hexavalent 

chromium emissions from chromium plating and chromic acid anodizing operations. A 

further goal is to isolate people from any new chromium plating or chromic acid anodizing 

facility. 

The primary benefit from the proposed amendments is a large reduction in excess cancer 

risk from emissions of hexavalent chromium. We estimate cancer risk would be reduced 

by up to 85 percent. Almost 75 percent of facilities would have cancer risk of less than 

one per million people exposed. About 92 percent of facilities would have cancer risk of 

less than ten per million people exposed. 

While the reduction in cancer risk is substantial, the overall air quality benefit, in terms of 

mass, is negligible. Moreover, reducing the cancer risk through adoption of the proposed 

amendments may have an affect on other environmental factors. As described below, 

while there may be some potential adverse impacts, ARB staff has determined that they 

are not significant. 

The legal requirements imposed on ARB to assess environmental impacts and our overall 

evaluation of the environmental impacts of the proposal are summarized below. We 

evaluated the potential impacts that the proposed amendments to the ATCM may have 

on air quality, wastewater treatment, and hazardous waste disposal. 

A. Legal Requirements 

The California Environmental Quality Act (CEQA) and ARB policy require an analysis to 

determine the potential environmental impacts of proposed regulations. ARB’s program 

for adopting regulations has been certified by the Secretary of Resources, pursuant to 

Public Resources Code section 21080.5. Consequently, the CEQA environmental 

analysis requirements may be included in the ISOR for this rulemaking. In the ISOR, the 

ARB must include a functionally equivalent document, rather than adhering to the format 

described in CEQA of an Initial Study, a Negative Declaration, and an Environmental 

Impact Report. In addition, staff will respond in the Final Statement of Reasons for the 

proposed amendments to the ATCM to all significant environmental issues raised by the 

public during the 45-day public review period or at the Board hearing. 
Chapter XI Page 119 

Public Resources Code section 21159 requires that the environmental impact analysis 

conducted by ARB include the following: 

• An analysis of reasonably foreseeable environmental impacts of the methods of 

compliance; 

• An analysis of reasonably foreseeable feasible mitigation measures; and 

• An analysis of reasonably foreseeable alternative means of compliance with the 

proposed amendments to the ATCM. 

Compliance with the proposed amendments to the Chromium Plating ATCM is expected 

to directly affect air quality and potentially affect other environmental media as well. Our 

analysis of the reasonably foreseeable environmental impacts of the methods of 

compliance is presented below. 

B. Analysis of Reasonably Foreseeable Environmental Impacts 

The proposed amendments reduce the public’s exposure to hexavalent chromium 

emissions from chromium plating and chromic acid anodizing facilities. The methods 

used to reduce the public’s exposure, however, will impact the environment. Our analysis 

of how the environment would be impacted follows. 

 1. Potential Air Quality Impacts

As previously discussed, hexavalent chromium is found in the particulate emissions from 

chromium plating and chromic acid anodizing facilities. However, the small reduction in 

hexavalent chromium emissions achieved from this proposal would have a negligible 

effect on ambient particulate levels. While the proposed amendments reduce emissions 

of hexavalent chromium by about 55 percent, the actual reduction in mass is about 

2.2 pounds per year. Remaining emissions are estimated to be 1.8 pounds per year. 

However, by reducing 2.2 pounds per year of hexavalent chromium, near source cancer 

risk impacts would be reduced by up to about 85 percent. These reductions will occur in 

eight air districts, with the greatest benefits occurring in the SCAQMD. 

The proposed amendments to the Chromium Plating ATCM are based on our 

reevaluation of BACT for reducing hexavalent chromium emissions from chromium plating 

and chromic acid anodizing facilities, in consideration of health risk and cost. The staff’s 

proposal would phase-in BACT over time. The timing for application of BACT would be 

related to throughput and proximity to sensitive receptors. 

By requiring BACT for all facilities, remaining cancer risks would be reduced by up to 85 

percent. We also estimate that adoption of the staff’s proposal will reduce the estimated 

cancer risk for 92 percent of facilities to less than or equal to ten per million exposed 

persons. The proposal would also isolate any new chromium plating or chromic acid 

anodizing facility from residential or mixed use zones by not allowing new facilities to 

operate in these areas. The new facility also could not operate within 150 meters of an 

area so zoned. 
Chapter XI Page 120 

Additional indirect air quality impacts will result from the implementation of the proposed 

amendment to the ATCM. It is anticipated that there will be a temporary increase in 

emissions of criteria pollutants due to construction related activity involved in the 

installation of new add-on air pollution controls and the possible dismantling of current 

controls. Staff finds that this short-term impact will not be significant. 

2. Potential Water and Wastewater Impacts

Many of the add-on air pollution control devices required by the proposed amendments 

require periodic water washdown to clean and maintain the integrity of the system. 

Implementation of housekeeping measures would likely require fresh water usage as well. 

This will increase the amount of freshwater used at these facilities. The increased water 

usage is difficult to quantify, however, we do not expect the increased use to be 

significant. A total of 89 facilities may increase water usage by installing add-on air 

pollution control devices. All of this freshwater becomes hazardous wastewater. 

However, water used to washdown control devices is often returned to the plating tank to 

reduce generation of hazardous waste. 

The State Water Resources Control Board (SWRCB) regulates wastewater in California. 

It is illegal to dispose into the sewer system, wastewater containing hazardous 

substances such as hexavalent chromium. Chromium plating and chromic acid anodizing 

facilities are subject to these regulations. While we expect the amount of wastewater to 

increase due to the proposed amendments related to housekeeping and equipment 

maintenance, by compliance with SWRCB regulations, we do not expect this hexavalent 

chromium to be discharged to lakes, rivers, bays, or oceans. 

Some facilities ‘treat’ their wastewater on site to precipitate the chromium from the water. 

This sludge, is also hazardous waste, but may be reused in the manufacture of stainless 

steel, thus further reducing the hazardous waste stream. 

3. Potential Hazardous Waste Impacts

Hazardous waste is regulated in California by federal and State laws. In California, all 

hazardous waste must be disposed of at a facility that is registered with the Department 

of Toxic Substances Control (DTSC). Chromium plating and chromic acid anodizing 

facility wastes are classified as hazardous waste because they contain hexavalent 

chromium. 

The proposed amendments, through housekeeping measures and disposal of HEPA 

filters and other pre-filters from the add-on air pollution control devices that capture 

hexavalent chromium, would increase the hazardous waste stream. 

The use of HEPA systems is already in wide use in the chromium plating and chromic 

acid anodizing industry in California. These filters, as well as pre-filters designed to 

increase the useful life of HEPA filters, are considered hazardous waste to be disposed of 

in Class A landfills. The proposed amendments would require an additional 89 facilities to 
Chapter XI Page 121 

begin using add-on air pollution control devices with the final collection mechanism likely 

to be HEPA filters. HEPA filters are usually replaced at least annually, but replacement 

schedules depend upon the individual operation. Pre-filters are replaced more often. 

We have estimated the impact of the incremental increase in the disposal of used filters 

due to the implementation of the proposed ATCM as follows: For our analysis, we 

assumed that each of the 89 affected facilities will be disposing of three filters per year, or 

89 x 3 = 267 filters per year. Assuming a typical filter volume of 4 cubic feet each, the 

resulting volume of hazardous waste generated will be 1,068 cubic feet per year 

(SCAQMD, 2003c). This corresponds to 2.9 cubic feet per day. We do not consider this 

to be a significant increase in the amount of hazardous waste to be landfilled. Moreover, 

staff has determined that the expected reduction in cancer risk from the proposed 

amendments overrides this increase in hazardous waste. 

 4. Potential Effect on the Environment due to Use of Persistent 

 and Bioaccumulative Perfluorooctyl Sulfonates (PFOS)

One of the hexavalent chromium control technologies in use today employs the use of 

chemical fume suppressants. The most common types of surfactants used in chromium 

electroplating and chromic acid anodizing are fluorinated or perfluorinated compounds, or 

simply, fluorosurfactants (U.S. EPA, 1998). 

The fluorosurfactants used as active ingredients in chemical fume suppressants are often 

referred to as perfluorooctyl sulfonates (PFOS). While these products are highly effective 

at reducing hexavalent chromium emissions by reducing plating bath surface tension the 

compounds have been shown to be persistent, bioaccumulative, and toxic to mammals 

(U.S. EPA, 2006). 

Studies indicate that PFOS may have potential developmental, reproductive, and 

systemic toxicity. PFOS compounds have been shown to be readily absorbed orally and 

distribute primarily to the serum and liver. Epidemiologic studies have also shown a link 

between exposure and the incidence of bladder cancer. PFOS compounds have also 

been shown to exhibit moderate toxicity in fish, aquatic plants, invertebrates, amphibians 

and birds (U.S. EPA, 2006). 

For these reasons, on March 10, 2006, U.S. EPA published at 40 CFR Part 721.9582, a 

proposal to add certain PFOS into their Significant New Use Rule for perfluoroalkyl 

sulfonates (PFAS). The PFOS proposed for addition include the PFOS commonly used 

in chemical fume suppressants. 

Our survey of the industry for calendar year 2003 indicated that 190 operations were 

using chemical fume suppressants as a mechanism to control hexavalent chromium 

emissions. Almost all of these facilities are using a chemical fume suppressant using 

PFOS as the active ingredient. We estimate that annually, over 800 gallons of chemical 

fume suppressant are currently used. The staff’s proposal does not require use of 

chemical fume suppressants except for very small operations. It is also possible that 
Chapter XI Page 122 

some facilities would cease to use chemical fume suppressants as a result of the staff’s 

proposal. However, when applications allow use of chemical fume suppressants, we 

expect facilities to continue using them to aid in emission reduction and to lengthen the 

useful life of HEPA filters. 

The proposed amendments would require an additional ten facilities with throughput 

below 20,000 ampere-hours to either begin using chemical fume suppressants or 

increase use of chemical fume suppressant to reduce surface tension to below 

40 dynes/centimeter. In total, we estimate the initial amount of chemical fume 

suppressant required to be 0.15 gallons. This is based on total ampere-hours (77,000) 

and the estimated use of 1.98 X 10-6 gallons of chemical fume suppressant per amperehour (SCAQMD, 2003b). Up to eight additional intermediate-sized facilities may begin 

using chemical fume suppressants if they choose to demonstrate compliance without use 

of an add-on air pollution control device. At most, the additional amount of chemical fume 

suppressant used would be three gallons. The chemical fume suppressant is usually 

supplied at concentrations of 5 to 10 percent PFOS. Typically, in plating/anodizing 

operations the concentration of PFOS in the plating/anodizing bath is 100 ppm (Atotech, 

2006a). 

Staff believes this estimate of additional chemical fume suppressant use to be negligible, 

and expect no significant impact to result from the staff’s proposal. 

 

The PFOS chemicals are not present on the finished plated part. Chemical fume 

suppressants are also known to break down in the plating/anodizing bath (Atotech, 

2006a), although the major loss of fume suppressant is due to dragout. Dragout can be 

reduced by part rinsing over the tank. It has been estimated that about ten percent of the 

chemical fume suppressant is discharged with wastewater (Atotech, 2006a). Thus, the 

potential of the general public’s exposure to PFOS compounds in the environment from 

plating and anodizing activities is low. 

Staff is not aware of any product other than PFOS that would be as effective at reducing 

hexavalent chromium while not damaging the plated part. To eliminate the potential of 

PFOS from chromium plating and chromic acid anodizing activities would require use of 

add-on air pollution control devices for all facilities, which we have concluded is not 

appropriate due to costs. Therefore, staff believes that the benefit from the reduction in 

excess cancers through the use of chemical fume suppressants containing PFOS 

outweighs the potential adverse impact to the environment due to use of PFOS. 

C. Reasonably Foreseeable Mitigation Measures 

The California Environmental Quality Act requires an agency to identify and adopt 

feasible mitigation measures that would minimize any significant adverse environmental 

impacts described in the environmental analysis. The ARB staff has concluded that no 

significant adverse environmental impacts should occur from adoption of and compliance 

with the proposed amendments to the ATCM. Because no significant adverse impacts 

have been identified, no specific mitigation measures would be necessary. 
Chapter XI Page 123 

D. Reasonably Foreseeable Alternative Means of Compliance 

Alternatives to the proposed amendments to the Chromium Plating ATCM are discussed 

in Chapter IX of this report. ARB staff has concluded that the proposed amendments to 

the ATCM provide the most effective and least burdensome approach to reducing the 

public’s exposure to hexavalent chromium emitted from chromium plating and chromic 

acid anodizing facilities. 

E. Community Health and Environmental Justice 

Environmental Justice is defined as the fair treatment of people of all races, cultures, and 

incomes with respect to the development, adoption, implementation, and enforcement of 

environmental laws, regulations, and policies. The ARB is committed to integrating 

environmental justice into all of our activities. ARB’s “Policies and Actions for 

Environmental Justice,” (Policies) establish our framework for incorporating 

Environmental Justice into the ARB’s programs, consistent with the directive of California 

state law (ARB, 2001b). These Policies apply to all communities in California. However, 

environmental justice issues have been raised specifically in the context of low-income 

areas and non-white communities. 

The Policies are intended to promote the fair treatment of all Californians and cover the 

full spectrum of the ARB’s activities. Underlying these Policies is a recognition that the 

agency needs to engage community members in a meaningful way as it carries out its 

activities. People should have the best possible information about the air they breathe 

and what is being done to reduce unhealthful air pollution in their communities. The ARB 

recognizes its obligation to work closely with all communities, environmental and public 

health organizations, industry, business owners, other agencies, and all other interested 

parties to successfully implement these Policies. 

During the development of the proposed amendments, ARB staff proactively identified 

and contacted chromium plating and chromic acid anodizing facility owners, 

environmental organizations, and other parties interested in chromium plating and 

chromic acid anodizing. These individuals participated by providing data, reviewing draft 

regulations, and attending public meetings in which staff directly addressed their 

concerns. 

Staff has found, through modeling analyses, that the health risks from hexavalent 

chromium emissions from chromium plating and chromic acid anodizing operations tend 

to be localized, and have the greatest impact on near-source receptors. For these 

reasons, staff has proposed amendments to reduce exposures to people and children by 

requiring highly effective controls, and phasing in these controls most quickly at larger 

facilities and those located nearer to sensitive receptors. Only very small operations (less 

than 20,000 ampere-hours) would not be required to meet an emission rate of 0.0015 

milligrams/ampere-hour. BACT for these facilities is specific chemical fume suppressants 
Chapter XI Page 124 

capable of reducing emissions to 0.01 milligrams/ampere-hour. However, these small 

facilities would pose a cancer risk of no more than one per million exposed people. All 

other facilities would need to demonstrate compliance with the 0.0015 milligram/amperehour limit. 

For facilities when application of BACT does not reduce cancer risk to below 25 per 

million exposed people, staff has proposed additional measures to require facilities to 

conduct a site specific analysis of emissions and health risk. The air districts will use this 

information to determine if further reductions are necessary. We estimate cancer risk 

would be reduced by up to 85 percent if the staff’s proposal were adopted. 

The proposed amendments to the ATCM are consistent with our Policies to reduce health 

risks from toxic air pollutants in all communities, including those with low-income and 

non-white populations, regardless of location. Potential health risks from hexavalent 

chromium emissions from chromium plating and chromic acid anodizing operations can 

affect both urban and rural communities. Therefore, reducing hexavalent chromium 

emissions from chromium plating and chromic acid anodizing operations will provide air 

quality benefits to urban and rural communities in the State, including low-income areas 

and non-white communities. 

We have identified several communities that may be disproportionately impacted from 

hexavalent chromium emissions from chromium plating and chromic acid anodizing 

operations. As an example, Appendix I, Chart 1 depicts chromium plating and chromic 

acid anodizing facilities in the Los Angeles/Orange County area. About 160 facilities are 

depicted on this Chart. The area shown within the box is magnified in Chart 2. Twentyfour facilities are located within this small area. This is almost 15 percent of all facilities 

represented in Chart 1. In Chart 2 we have identified those areas where over 30 percent 

of the residents have incomes below the poverty level (hatched areas). Six facilities are 

located within this area. Table XI-1 shows the number of facilities located in non-white 

areas and in areas with a high poverty rate. 

Table XI-1. Distribution of Chromium Plating and Chromic Acid Anodizing 

 Facilities in the Los Angeles and Orange County Areas 

Location 

Total 

Number of 

Facilities 

30 to 100% 

Below 

Poverty 

Over 90% 

Non-white*

Combined 30 to 100% 

Below Poverty and 

Over 90% Non-white 

Los Angeles and 

Orange Counties 160 38 80 38 

Compton Area 24 6 20 6 

* Non-white is defined as the sum of all other races that are not included in the “white-alone” one race category in the 2000 census 

 data prepared by the U.S. Census Bureau. 

Table XI-1 shows that half of the facilities in the Los Angeles and Orange County areas 

are located in areas where over 90 percent of the population is non-white. In our analysis 

of 2000 U.S. census data, we created the category percent non-white to serve as 

measure of ethnic diversity on a census tract. The percent non-white value is calculated 
Chapter XI Page 125 

from the sum of all other races that are not included in the “white-alone” one-race 

category in the 2000 census data prepared by the U.S. Census Bureau. Of these, 

38 facilities (almost 25 percent) are located in areas where the poverty level is 

30 percent or more. Similarly for the Compton area, 20 facilities (about 80 percent of the 

facilities shown in Chart 2) are located in non-white areas, with six of these facilities 

located in areas where the poverty level exceeds 30 percent. Staff believes this 

concentration of plating/anodizing operations in low-income and non-white communities 

has created disproportionate impacts from hexavalent chromium emissions from 

chromium plating and chromic acid anodizing facilities. Because the proposed 

amendments to the ATCM would greatly reduce these emissions in residential areas, 

these communities would realize a major portion of the benefits from the proposal. 

To further address environmental justice and the public’s concern about developing 

cancer from exposure to hexavalent chromium emissions at all locations, including 

currently heavily impacted communities, the proposed amendments to the ATCM 

establish criteria for the operation of new chromium plating and anodizing facilities. Staff 

is proposing that any new facility would not be able to operate in any area zoned as 

residential or mixed use, or within 150 meters of a residential or mixed use zone. Also, 

new chromium plating and chromic acid anodizing facilities would be required to install 

add-on air pollution control devices that provide the maximum hexavalent chromium 

reduction and undergo a site-specific analysis to ensure adequate protection of public 

health. These criteria will help ensure that new chromium plating and chromic acid 

anodizing facilities are not operated in areas where people live. 

We believe these criteria are necessary to protect people from exposures to hexavalent 

chromium, an extremely potent, known human carcinogen. While we believe these 

precautions are necessary in this case, similar requirements may not be appropriate for 

sources of other TACs. Each TAC should be evaluated on a case by case basis to 

determine the appropriate methods to protect public health and reduce exposure. 
Chapter XI Page 126 

REFERENCES 

ARB, 2001b. Air Resources Board. “Policies and Actions for Environmental Justice”. 

2001 

Atotech, 2006a. Atotech USA Inc, GW Walker. Draft Letter to US EPA regarding 

proposed amendments to the Significant New Use Rule (SNUR) for perfluoroalkyl 

sulfonates (Docket ID: EPA-HQ-OPPT-2005-0015). 2006. 

SCAQMD, 2003b. South Coast Air Quality Management District. “Draft Socioeconomic 

Assessment for Proposed Amendments to Rule 1469-Hexavalent Chromium Emissions 

from Chrome Plating and Chromic Acid Anodizing Operations and Proposed Rule 1426-

Emissions from Metal Finishing Operations”. 2003 

SCAQMD, 2003c. South Coast Air Quality Management District, “Final Environmental 

Assessment: Proposed Rule 1426 – Emissions from Metal Finishing Operations; and, 

Proposed Amended Rule 1469 – Hexavalent Chromium Emissions from Chrome Plating 

and Chromic Acid Anodizing Operations.” 2003 

U.S. EPA, 1998. U.S. Environmental Protection Agency. EPA/625/R-98/002: “Capsule 

Report Hard Chrome Fume Suppressants and Control Technologies”. 1998. 

U.S. EPA, 2006. U.S. Environmental Protection Agency. 40 CFR Part 721: 

“Perfluoroalkyl Sulfonates; Proposed Significant New Use Rule.” 2006. 
Appendix A 

Proposed Regulation Order for the Proposed 

Amendments to the Chromium Plating ATCM 
1

Hexavalent Chromium Airborne Toxic Control Measure (ATCM) for Chrome 

Plating and Chromic Acid Anodizing Operations 

[Note: The proposed amendments are shown in strikeout to indicate proposed 

deletions and underline to indicate proposed additions. New quotation marks 

have been added to the definitions in section 93102.3; these quotation marks 

have not been underlined to make the regulations easier to read. In addition, 

explanatory notes are included after or before some provisions of the regulations. 

They are not part of the regulations; they are included for clarity and are shown in 

brackets and italics: [Note......]

Amend title 17, California Code of Regulations, Section 93102, to read as 

follows; the amendments include a reorganization of section 93102 so that its 

provisions are now contained in sections 93102-93102.16: 

Section 93102. Hexavalent Chromium Airborne Toxic Control Measure for 

Chrome Chromium Plating and Chromic Acid Anodizing 

Operations Facilities. 

The Airborne Toxic Control Measure for Chromium Plating and 

Chromic Acid Anodizing Facilities (ATCM) is contained in 

sections 93102 through 93102.16. The ATCM is organized as 

follows:

Sections 93102 through 93102.3 specify the applicability of the 

ATCM, exemptions, and definitions. Section 93102.4 sets forth 

requirements that differ depending on whether a facility is an 

existing facility, a modified facility, or a new facility. Section 

93102.5 sets forth various new requirements that apply to all 

facilities beginning [Effective Date] (i.e., all existing, modified, 

and new facilities). Section 93102.6 contains special provisions 

that apply only to enclosed hexavalent chromium electroplating 

facilities and facilities that perform electroplating using a 

trivalent chromium bath. Sections 93102.7 through 93102.14 

contain additional requirements that apply to all facilities. Most 

of the requirements in sections 93102.7 through 93102.14 have 

been in effect since 1998. Section 93102.15 sets forth 

requirements that apply to the manufacture, sale, supply, offer 

for sale, and use of chromium plating and chromic acid 

anodizing kits in California. There are eight appendices to the 

ATCM; these appendices are contained in section 93102.6. 
2

93102.1(a) Applicability.

(a) This regulation shall apply to: 

(1) The owner or operator of each chromium electroplating or 

chromic acid anodizing tank at facilities any facility performing 

hard chromium electroplating, decorative chromium 

electroplating, or chromic acid anodizing. 

(2) Any person who sells, supplies, offers for sale, uses, or 

manufactures for sale in California a chromium plating or 

chromic acid anodizing kit. 

(b)(5) Title V Permits.

 The owner or operator of a major source subject to the requirements 

of this section is required to obtain a title V permit (See 42 U.S.C. 

7401, et seq.) from the permitting authority of the district in which the 

major source is located. 

(c) Severability. 

Each part of this ATCM shall be deemed severable, and in the event 

that any part of this ATCM is held to be invalid, the remainder of this 

ATCM shall continue in full force and effect.

93102.2 (2) Exemptions.

(a) This regulation shall not apply to process tanks associated with a 

chromium electroplating or chromic acid anodizing process, but in 

which neither chromium electroplating nor chromic acid anodizing is 

taking place. Examples of such tanks include, but are not limited to, 

rinse tanks, etching tanks, electro stripping tanks and cleaning tanks. 

Tanks that contain a chromium solution, but in which no electrolytic 

process occurs, are not subject to this regulation. An example of 

such a tank is a chromium conversion coating tank where no 

electrical current is applied.

(3) The requirements of subsections (e)), (f ), and (g) do not apply to 

decorative chromium electroplating tanks using a trivalent 

chromium bath with a wetting agent.

(b)(4) The requirements of subsections 93102.4 (c) and (g) 93102.11 do 

not apply during periods of equipment breakdown, provided the 

provisions of the permitting agency's breakdown rule are met (see 

Appendix 6). 
3

93102.3 (b) Definitions. 

(a) For the purposes of this regulation, the following definitions shall 

apply:

(1) “Add-on air pollution control device” means equipment 

installed in the ventilation system of chromium electroplating 

and anodizing tanks for the purposes of collecting and 

containing chromium emissions from the tank(s). 

(2) “Air pollution control technique” means any method, such as 

an add-on air pollution control device, mechanical fume 

suppressant or a chemical fume suppressant, that is used to 

reduce chromium emissions from chromium electroplating and 

chromic acid anodizing tanks. 

(3) “Ampere-hours” means the integral of electrical current applied 

to a plating tank (amperes) over a period of time (hours). 

(4) “Annual Permitted Ampere-hour” means the maximum 

allowable chromium plating or anodizing rectifier production in

ampere-hours, on an annual basis as specified in the 

permitting agency's Permit to Operate for the facility.

(5)(4) “Area source” means any stationary source of hazardous air 

pollutants that is not a major source as defined in this part. 

 

(6)(5) “Base material” metal means the metal or metal alloy, or 

plastic that comprises the workpiece. 

 

(7)(6) “Bath component” means the trade or brand name of each 

component(s) in trivalent chromium plating baths. For trivalent 

chromium baths, the bath composition is proprietary in most 

cases. Therefore, the trade or brand name for each 

component(s) can be used; however, the chemical name of 

the wetting agent contained in that component must be 

identified. 

 

(8)(7) “Breakdown” means an unforeseeable impairment of an air 

pollution control equipment or related operating equipment 

which causes a violation of any emission limitation or 

restriction prescribed by a permitting agency's rule or by State 

law and which: is not the result of neglect or disregard of any 

air pollution control law, rule, or regulation; is not intentional or 

the result of negligence, or improper maintenance; is not a 
4

recurrent breakdown of the same equipment; and, does not 

constitute a nuisance pursuant to section 41700 of the 

California Health and Safety Code, with the burden of proving 

the criteria of this section placed upon the person seeking to 

come under the provisions of this law. 

 

(9)(8) “Chemical fume suppressant” means any chemical agent that 

reduces or suppresses fumes or mists at the surface of an 

electroplating or anodizing bath; another term for fume 

suppressant is mist suppressant. 

 

(10)(9) “Chromic acid” means the common name for chromium 

anhydride (CrO3). 

 

(11)(10) “Chromic acid anodizing” means the electrolytic process by 

which an oxide layer is produced on the surface of a base 

metal material for functional purposes (e.g., corrosion 

resistance or electrical insulation) using a chromic acid 

solution. In chromic acid anodizing, the part to be anodized 

acts as the anode in the electrical circuit, and the chromic acid 

solution, with a concentration typically ranging from 

50 to 100 grams per liter (g/L), serves as the electrolyte. 

 

(12)(11) “Chromium electroplating or chromic acid anodizing tank”

means the receptacle or container in which hard or decorative 

chromium electroplating or chromic acid anodizing occurs.,

along with the following accompanying internal and external 

tank components needed for chromium electroplating or 

chromic acid anodizing. These tank components include, but 

are not limited to, rectifiers fitted with controls to allow for 

voltage adjustments, heat exchanger equipment, and 

circulation pumps.

 

(13)(12) “Composite mesh-pad system” means an add-on air pollution 

control device typically consisting of several mesh-pad stages 

to remove particles. The purpose of the first stage is to 

remove large particles. Smaller particles are removed in the 

second stage, which consists of the composite mesh pad. A 

final stage may remove any reentrained particles not collected 

by the composite mesh pad.

 

(14)(13) “Decorative chromium electroplating” means the process by 

which a thin layer of chromium (typically 0.003 to 

2.5 micronsmeters) is electrodeposited on a base metal, 

plastic, or undercoating material to provide a bright surface 

with wear and tarnish resistance. In this process, the part(s) 

serves as the cathode in the electrolytic cell and the solution 
5

serves as the electrolyte. Typical current density applied 

during this process ranges from 540 to 2,400 Amperes per 

square meter (A/m2

) for total plating times ranging between 

0.5 to 5 minutes. 

 

(15) “Dragout” means fluid containing hexavalent chromium that 

adheres to parts when they are removed from a tank.

(16)(14) “Electroplating or anodizing bath” means the electrolytic 

solution used as the conducting medium in which the flow of 

current is accompanied by movement of metal ions for the 

purpose of electroplating metal out of the solution onto a 

workpiece or for oxidizing the base material. 

 

(17)(15) “Emission limitation” means, for the purposes of this section

trivalent chromium plating, the concentration of total chromium 

allowed to be emitted expressed in milligrams per dry standard 

cubic meter (mg/dscm),. For hexavalent chromium plating or 

anodizing, or the allowable surface tension expressed in 

dynes per centimeter (dynes/cm) for decorative chromium

electroplating and chromic acid anodizing tanks; or and the 

milligrams of hexavalent chromium per ampere-hour 

(mg/amp-hr) of electrical charge applied to the chromium 

electroplating or anodizing tank, or the concentration of 

chromium allowed to be emitted expressed in milligrams per 

dry standard cubic meter (mg/dscm). for hard chromium 

electroplating tanks.

(18) “Enclosed storage area” means any space or structure used to 

contain material that prevents its contents from being emitted 

into the atmosphere. This includes cabinets, closets or sheds 

designated for storage.

(19) “Enclosed hexavalent chromium electroplating tank” means a 

hard, decorative or chromic acid anodizing tank using a 

hexavalent chromium solution that is equipped with an 

enclosing hood and ventilated at half the rate or less that of an 

ventilated open surface tank of the same surface area. 

(20) "Existing Facility" means a facility that is in operation before 

[Effective Date].

 

(21)(16) “Facility” means the major or area source at which chromium 

electroplating or chromic acid anodizing is performed. and/or 

any source or group of sources or other contaminant-emitting 

activities which are located on one or more contiguous 
6

properties within the District, in actual physical contact or 

separated solely by a public roadway or other public 

right-of way, and are owned or operated by the same person 

(or by persons under common control), or an outer continental 

shelf (OCS) source as determined in 40 CFR Section 55.2.

 

(22)(17) “Fiber-bed mist eliminator” means an add-on air pollution 

control device that removes contaminants particles from a gas 

stream through the mechanisms of inertial impaction and 

Brownian diffusion. These devices are typically installed 

downstream of another control device, which serves to prevent 

plugging, and consist of one or more fiber beds. Each bed 

consists of a hollow cylinder formed from two concentric 

screens; the fiber between the screens may be fabricated from 

glass, ceramic, plastic, or metal.

 

(23)(18) “Foam blanket” means the type of chemical fume suppressant 

that generates a layer of foam across the surface of a solution 

when current is applied to that solution. A foam blanket does 

not lower surface tension of a liquid. 

 

(24)(19) “Fresh water” means water, such as tap water, that has not 

been previously used in a process operation or, if the water 

has been recycled from a process operation, it has been 

treated and meets the effluent guidelines for chromium 

wastewater. 

 

(25) “Fugitive dust” means any solid particulate matter that may 

contain hexavalent chromium that has the potential to become 

airborne by natural or man-made activities. “Fugitive dust” 

does not include particulate matter emitted from an exhaust 

stack. 

 

(26)(20) “Hard chromium electroplating or industrial chromium 

electroplating” means a process by which a thick layer of 

chromium (typically greater than 1.0 micrometersns) is 

electrodeposited on a base material to provide a surface with 

functional properties such as wear resistance, a low coefficient 

of friction, hardness, and corrosion resistance. In this process, 

the part serves as the cathode in the electrolytic cell and the 

solution serves as the electrolyte. The Hhard chromium 

electroplating process is performed at current densities 

typically ranging from 1,600 to 6,500 A/m2 for total plating 

times ranging from 20 minutes to 36 hours depending upon 

the desired plate thickness. 

 
7

(27)(21) “Hexavalent chromium” means the form of chromium in a 

valence state of +6. 

 

(28)(22) “High Efficiency Particulate Air Arrestor (HEPA) filter” means 

filter(s) rated at 99.97 percent or more efficient in collecting 

particle sizes 0.3 micrometersns or larger. 

(29) "Initial Startup" means the first time a new facility begins 

production or the first time a modified chromium plating or 

anodizing tank begins operating at a modified facility. If such 

production or operation occurs prior to [Effective date], the 

date of "Initial Startup" is [Effective date]. "Initial Startup" does 

not include operation solely for testing of equipment or 

subsequent startup of permit units following malfunction or 

shutdown. 

 

(30)(23) “Large, hard chromium electroplating facility” means a facility 

that performs hard chromium electroplating and emits greater 

than or equal to 10 pounds per year (lbs/yr) controlled 

emissions of hexavalent chromium. 

 

(31)(24) “Leak” means the release of chromium emissions from any 

opening in the emission collection system prior to exiting the 

emission control device. 

 

(32)(25) “Major source” means any stationary source or group of 

stationary sources located within a contiguous area and under 

common control that emits or has the potential to emit 

considering controls, in the aggregate, 10 tons per year or 

more of any hazardous air pollutant or 25 tons per year or 

more of any combination of hazardous air pollutants. 

 

(33)(26) “Maximum cumulative potential rectifier capacity” means the 

summation of the total installed rectifier capacity associated 

with the hard chromium electroplating tanks at a facility, 

expressed in amperes, multiplied by the maximum potential 

operating schedule of 8,400 hours per year and 0.7, which 

assumes that electrodes are energized 70 percent of the total 

operating time. The maximum potential operating schedule is 

based on operating 24 hours per day, 7 days per week, 

50 weeks per year. 

 

(34)(27) “Mechanical fume suppressant” means any device, including 

but not limited to polyballs, that reduces fumes or mist at the 

surfaces of an electroplating or anodizing bath by direct 
8

contact with the surface of the bath. Polyballs are the most 

commonly used mechanical fume suppressant.

 

(35)(28) “Medium, hard chromium electroplating facility” means a 

facility that performs hard chromium electroplating and emits 

greater than 2 pounds per year (lbs/yr) controlled emissions 

but less than 10 pounds per year (lbs/yr) controlled emissions 

of hexavalent chromium. 

 

(36)(29) “Modification” means either: 

 

(A) any physical change in, change in method of operation of, 

or addition to an existing permit unit that requires an 

application for a permit to construct and/or operate and 

results in an increase in hexavalent chromium emissions. 

Routine maintenance and/or repair shall not be considered 

a physical change. A change in the method of operation of 

equipment, unless previously limited by an enforceable 

permit condition, shall not include: 

1. an increase in the production rate, unless such increases 

will cause the maximum design capacity of the equipment 

to be exceeded; or

1. 2. an increase in the hours of operation; or 

2. 3. a change in ownership of a facility source; or 

3. an increase in the annual ampere-hours, unless such 

increase will cause a facility to move from a lower tier to 

a higher tier in Table 93102.4 of section 93102.4. 

(B) The the addition of any new chromium plating or anodizing 

tank permit unit at an existing facility source which 

increases hexavalent chromium emissions; or 

(C) the fixed capital cost of the replacement of components 

exceeding 50 percent of the fixed capital cost that would be 

required to construct a comparable new facility source. 

(37) "Modified Facility" means any facility which has undergone a 

modification.

(38) "New Facility" means any facility that begins initial operations 

on or after [Effective Date]. "New Facility" does not include 
9

the installation of a new chromium plating or anodizing tank at 

an existing facility or the modification of an existing facility.

(39)(30) “Operating parameter value” means a minimum or maximum 

value established for a control device or process parameter 

which, if achieved by itself or in combination with one or more 

other operating parameter values, determines that an owner or 

operator is in continual compliance with the applicable 

emission limitation or standard. 

(40) “Owner or Operator” means a person who is the owner or the 

operator of a facility performing hard chromium electroplating, 

decorative chromium electroplating, or chromic acid anodizing.

 

(41)(31) “Packed-bed scrubber” means an add-on air pollution control 

device consisting of a single or double packed-bed that 

contains packing media on which the chromic acid droplets 

impinge. The packed-bed section of the scrubber is followed 

by a mist eliminator to remove any water entrained from the 

packed-bed section.

 

(42) “Permitting Agency” means the local air pollution control or air 

quality management district.

(43) "Person" shall have the same meaning as defined in Health 

and Safety Code section 39047.

(44)(32) “Responsible official” means one of the following: 

(A) For a corporation: A president, secretary, treasurer, or vice 

president of the corporation in charge of a principal 

business function, or any other person who performs 

similar policy or decision-making functions for the 

corporation, or a duly authorized representative of such 

person if the representative is responsible for the overall 

operation of one or more manufacturing, production, or 

operating facilities and either: 

1. The facilities employ more than 250 persons or have 

gross annual sales or expenditures exceeding $25 million 

(in second quarter 1980 dollars); or 

2. The delegation of authority to such representative is 

approved in advance by the Administrator. 
10

(B) For a partnership or sole proprietorship: a general partner 

or the proprietor, respectively. 

(C) For a municipality, state, Federal, or other public agency: 

either a principal executive officer or ranking elected 

official. For the purposes of this part, a principal executive 

officer of a Federal agency includes the chief executive 

officer having responsibility for the overall operations of a 

principal geographic unit of the agency (e.g., a Regional 

Administrator of the U.S. EPA). 

(D) For sources (as defined in this part) applying for or subject 

to a title V permit: "responsible official" shall have the 

same meaning as defined in 40 CFR Part 70 or federal title 

V regulations in this chapter (42 U.S.C. 7401, et seq.), 

whichever is applicable. 

 

(45)(33) “Small, hard chromium electroplating facility” means a facility 

that performs hard chromium electroplating and emits less 

than or equal to 2 pounds per year (lbs/yr) controlled 

emissions of hexavalent chromium. 

(46) “Sensitive receptor” means any residence including private 

homes, condominiums, apartments, and living quarters; 

education resources such as preschools and kindergarten 

through grade twelve (k-12) schools; daycare centers; and 

health care facilities such as hospitals or retirement and 

nursing homes. A sensitive receptor includes long term care 

hospitals, hospices, prisons, and dormitories or similar live-in 

housing.

(47)(34) “Source” means any chromium electroplating or chromic acid 

anodizing operation and any equipment or materials 

associated with the selected associated air pollution control 

technique. 

(48)(35) “Stalagmometer” means a device used to measure the surface 

tension of a solution. an instrument used to measure the 

surface tension of a solution by determining the mass of a 

drop of liquid by weighing a known number of drops or by 

counting the number of drops obtained from a given volume of 

liquid. 

(49)(36) “Surface tension” means the property, due to molecular forces, 

that exists in the surface film of all liquids and tends to prevent 

liquid from spreading. 
11

 

(50) “Tank” means the structure or receptacle containing the 

electroplating or anodizing bath.

(51)(37) “Tank operation” means the time in which current and/or 

voltage is being applied to a chromium electroplating tank or a 

chromic acid anodizing tank. 

 

(52)(38) “Tensiometer” means a device used to measure the surface 

tension of a solution. an instrument used to measure the 

surface tension of a solution by determining the amount of 

force needed to pull a ring from the liquid surface. The 

amount of force is proportional to the surface tension.

(53)(39) “Trivalent chromium” means the form of chromium in a 

valence state of +3. 

(54)(40) “Trivalent chromium process” means the process used for 

electrodeposition of a thin layer of chromium onto a base 

material using a trivalent chromium solution instead of a 

chromic acid solution. 

 

(55)(41) “Weekly” means at least once every seven calendar days. 

(56)(42) “Wetting agent” means the type of chemical fume suppressant 

that reduces the surface tension of a liquid. 

93102.4 (c) Standards Requirements for Existing, Modified, and New 

Hexavalent Chromium Plating and Chromic Acid Anodizing

Facilities. 

This section 93102.4 sets forth requirements that apply to all 

hexavalent chromium hard and decorative chromium 

electroplating and chromic acid anodizing facilities, except for 

facilities subject to section 93102.6 (i.e., facilities that perform 

electroplating using a trivalent chromium bath and are enclosed 

hexavalent chromium electroplating facilities). The 

requirements differ depending on whether a facility is an existing 

facility, a modified facility or a new facility. Additional 

requirements that apply to all facilities (i.e., all existing, modified, 

and new facilities) are contained in section 93102.5 and 

sections 93102.7 through 93102.14. 

Subsection (a) contains the requirements to reduce hexavalent 

chromium emissions that were in effect before [Effective Date]. 

The limits in subsection (a) shall remain in effect for a facility 
12

until the limits in subsection (b) become effective. Once the 

limits in subsection (b) become effective for an individual facility 

the limits in subsection (a) no longer apply.

The limits in subsection (b) are phased in depending on the 

amount of annual permitted ampere-hours and the distance to 

the nearest sensitive receptor. Depending on the facility, limits 

in subsection (b) become effective on [Six Months after Effective 

Date], [Two Years after Effective Date], or [Five Years after 

Effective Date]. 

(a)(1) Requirements that Apply to Existing Hexavalent Chromium 

Electroplating and Chromic Acid Anodizing Facilities. 

 An existing facility is a facility that is in operation before [Effective 

Date]. 

In addition to the limits specified in this subsection (a) all facilities 

(i.e., all existing, modified, and new facilities) must comply with the 

applicable provisions contained in section 93102.5 and sections 

93102.7 through 93102.14.

(1) Limits that Apply to Existing Hard Chromium Electroplating 

Facilities Until the Limits in subsection (b) Become Effective.

 Hard Chrome Electroplating Operations.

During tank operation, each owner or operator of an existing,

modified, or new source facility shall control hexavalent 

chromium emissions discharged to the atmosphere from that 

facility source by reducing the hexavalent chromium emissions 

from the add-on air pollution control device(s) serving the 

electroplating tank(s) as identified below. 
13

(A) Limits that Apply Until the Limits in subsection (b) Become 

Effective for Existing Operations (on or before 12/16/93)

Hard Chromium Electroplating Facilities that Began 

Operations on or before December 16, 1993.

Requirement 

< 60 million 

amp-hrs2

 > 60 million amp-hrs2

Facility Size Controlled 

emissions1

(lbs/yr) 

 Option 1 Option 23

Large > 10 lbs/yr < 0.006 

mg/amp-hr 

< 0.006 

mg/amp-hr 

< 0.006 

mg/amp-hr 

Medium < 10 lbs/yr but 

> 2 lbs/yr 

< 0.03 

mg/amp-hr 

< 0.006 

mg/amp-hr 

< 0.03 

mg/amp-hr 

and 0.015 

mg/dscm 

Small < 2 lbs/yr < 0.15 

mg/amp-hr 

< 0.03 

mg/amp-hr 

< 0.15 

mg/amp-hr 

and 0.015 

mg/dscm 

(B) New and/or Modified Operations (after 12/16/93) Limits 

that Apply Until the Limits in subsection (b) Become 

Effective for Existing Hard Chromium Electroplating 

Facilities that Began Operations after December 16, 1993,

and Before [Effective Date].

Facility Size Controlled Requirement 

Emissions1

 (lbs/yr) < 60 million amphrs2

 > 60 million amphrs2

Large > 10 lbs/yr < 0.006 mg/amphr < 0.006 mg/amphr 

Medium/ Small < 10 lbs/yr < 0.03 mg/amp-hr < 0.006 mg/amphr

1 combined hexavalent or total chrome chromium emissions from hard chrome

chromium plating operations. 

2

 maximum cumulative potential rectifier capacity or usage limit. 

3

 “Option 2” is an alternative emission limitation for small and medium facilities 

 that elect to demonstrate compliance with both a mg/amp-hr and a mg/dscm 

 requirement. 

(C) Special Provisions that Apply for some Hard Chromium 

Electroplating Facilities Using Less than or Equal to 

500,000 Ampere-hours per Year Until the Limits in 

subsection (b) Become Effective. Very small operations 

using less than or equal to 500,000 ampere-hours per 

year.
14

The permitting agency may approve, on a case-by-case 

basis, alternative standards for small hard chrome plating 

operations chromium electroplating facilities using less 

than or equal to 500,000 ampere-hours per year. The 

operation must have been constructed on or before 

December 16, 1993. At a minimum, the source facility

must use a chemical fume suppressant containing a 

wetting agent to lower the surface tension of the plating 

bath to at least 45 dynes per centimeter (dynes/cm) 

(3.1x10-3 pound-force per foot [lbF/ft]). The permitting 

agency may require additional emission reduction 

techniques as necessary to reduce the public health impact 

of emissions from the operation. The owner or operator 

must comply with the applicable monitoring [subsection (e)

93102.9], recordkeeping [subsection (h) 93102.12], and 

reporting [subsection (i) 93102.13] requirements. The 

owner or operator must submit a plan to the permitting 

agency describing the alternative technique and identifying 

appropriate monitoring, recordkeeping, and reporting 

requirements. The permitting agency, with U.S. EPA 

concurrence, shall approve this plan if equivalent results 

are obtained. Upon approval, the requirements identified 

in the plan shall be the applicable requirements under this 

regulation. 

(2) Requirements that Apply to Existing Hexavalent Decorative 

Chromeium Electroplating and Chromic Acid Anodizing 

Facilities Until the Limits in subsection (b) Become Effective.

During tank operation, each owner or operator of an existing,

modified, or new source decorative hexavalent chromium 

electroplating or chromic acid anodizing facility shall control 

hexavalent chromium emissions discharged to the atmosphere by 

meeting either of the requirements identified below. 

Method of compliance Requirement 

1. add-on air pollution control 

equipment, or chemical fume 

suppressants, or mechanical fume 

suppressants (i.e. polyballs) 

0.01 milligrams per dry standard cubic 

meter of air (mg/dscm) 

(4.4x10-6 gr/dscf) 

2. chemical fume suppressants 

containing a wetting agent 

45 dynes per centimeter (dynes/cm) 

(3.1x10-3 pound-force per foot [lbF/ft]) 
15

(b) Limits that Apply to All Existing Hexavalent Hard and Decorative 

Chromium Electroplating and Chromic Acid Anodizing Facilities After 

[Effective Date].

(1) During tank(s) operation, each owner or operator of an 

existing hexavalent chromium facility shall control hexavalent 

chromium emissions discharged to the atmosphere by 

meeting the requirements identified below. 

[Table 93102.4 is a newly proposed table. It is not shown in underline for 

clarity]

Table 93102.4: Hexavalent Chromium Emission Limits for Existing 

 Facilities 

Tiers of 

Annual 

Permitted 

Ampere-Hours

Sensitive 

Receptor 

Distance 1

Emission Limitation Effective Date 

Tier 1 

< 20,000 Any 

Use Chemical Fume Suppressant as 

specified in section 93102.8 2

[Six Months after 

Effective Date] 

Tier 2 

> 20,000 and 

< 200,000 

< 100 

Meters 

0.0015 milligrams/ampere-hour 3 [Two Years after 

Effective Date] 

Tier 3 

> 20,000 and 

< 200,000 

> 100 

Meters 

0.0015 milligrams/ampere-hour 3[Five Years after 

Effective Date] 

Tier 4 

> 200,000 

Any 0.0015 milligrams/ampere-hour 4, 5 [Two Years after 

Effective Date] 

1

 Distance shall be evaluated by the permitting agency. 

2

 Alternatively, [Two Years after Effective Date] facility shall comply with the requirement for 

 facilities with > 20,000 and < 200,000 annual permitted ampere-hours. 

3

 Emission limit compliance may be demonstrated without using add-on air pollution control 

device(s). If an add-on air pollution control device has been installed, the emission 

limitation shall be measured after the add-on air pollution control device. 

4 Measured after add-on air pollution control device(s). 

5

 When actual annual emissions exceed 15 grams a site specific analysis must be conducted 

 in accordance with the permitting agency’s procedures.

(2) Demonstrating Compliance with the Emission Limitation in 

Table 93102.4

(A) Facilities complying with Tier 2 or Tier 3 requirements in 

Table 93102.4 may demonstrate compliance with the 

emission limitation of 0.0015 milligrams/ampere-hour 

without the use of an add-on air pollution control device(s). 

At a minimum, if the facility is demonstrating compliance 
16

with the Tier 2 or Tier 3 requirements in Table 93102.4 

without an add-on air pollution control device(s), the facility 

must use a chemical fume suppressant as specified in 

section 93102.8.

(B) Facilities complying with Tier 4 requirements in 

 Table 93102.4 must use an add-on air pollution control 

device(s) to control hexavalent chromium emissions and 

demonstrate compliance with the emission limitation of 

0.0015 milligrams/ampere-hour as measured after the 

 add-on air pollution control device.

(c) Requirements for Modified Hexavalent Chromium Electroplating or 

Chromic Acid Anodizing Facilities. 

(1) During tank operation, each owner or operator of a 

modified facility shall upon initial start-up control 

hexavalent chromium emissions discharged to the 

atmosphere from that facility by reducing the hexavalent 

chromium emissions from the electroplating or anodizing 

tank(s) by:

(A) Using an add-on air pollution device(s) to control 

hexavalent chromium emissions, and

(B) Meeting an emission limit of 0.0015 milligrams per 

ampere-hour or less as measured after add-on controls. 

(2) Prior to initial start-up of a modified facility, with actual annual

emissions of hexavalent chromium exceeding 15 grams per 

year, the owner or operator shall conduct a site specific 

analysis in accordance with the permitting agency’s 

procedures. 

(d) Requirements for New Hexavalent Chromium Electroplating and 

Chromic Acid Anodizing Facilities Beginning [Effective Date].

(1) No person shall operate a new facility unless it is located 

outside of an area that is zoned for residential or mixed use 

and is located at least 150 meters from the boundary of any 

area that is zoned for residential or mixed use as determined 

by the permitting agency.

(A) A new facility shall be deemed to meet the requirements 

specified in this subsection (d)(1) if one of the following 

criteria is met, even if the facility does not meet the 
17

requirement at the time of initial startup (e.g., because of a 

zoning change that occurs after the authority to construct is 

issued):

1. The requirements specified in this subsection (d)(1) are 

met at the time it is issued an authority to construct by 

the permitting agency, and substantial use of the 

authority to construct takes place within one year after it 

is issued; or

2. The requirements specified in this subsection (d)(1) are 

met at the time it is issued an authority to construct by 

the permitting agency, and substantial use of the 

authority to construct takes place before any zoning 

change occurs that affects the operation’s ability to meet 

the requirement at the time of initial startup.

(2) During tank operation, each owner or operator of a new facility

shall control hexavalent chromium emissions discharged to 

the atmosphere from that facility by reducing the hexavalent 

chromium emissions from the electroplating or anodizing 

tank(s) by installing a HEPA add-on air pollution control 

device. The measured emission rate of hexavalent chromium 

shall be no more than 0.0015 milligrams per ampere-hour as 

measured after the HEPA add-on air pollution control device.

(3) Prior to initial start-up each new facility shall conduct a site 

specific analysis in accordance with the permitting agency’s 

procedures. 

(4) Prior to initial startup, each new facility shall demonstrate to 

the permitting agency that the new facility meets the 

requirements specified in this subsection (d).
18

(3) Decorative Chromium Electroplating Tanks Using a Trivalent Chromium 

Bath.

[Note: This subsection has been modified and moved to section 93102.6 of 

this regulation] 

During tank operation, each owner or operator of an existing, modified, or 

new source shall control chromium emissions discharged to the 

atmosphere by meeting either of the requirements identified below. 

 

Method of compliance Requirement

add-on air pollution control equipment, 

or chemical fume suppressants, or 

mechanical fume suppressants (i.e. 

polyballs)

< 0.01 mg/dscm (4.4x10-6

 gr/dscf)

chemical fume suppressants containing 

a wetting agent

use wetting agent as bath ingredient 

and comply with recordkeeping and 

reporting provisions of subsections 

(h)(9) and (i)(5).

(e) Notification Requirements for New and Modified Facilities. 

[Note: This subsection has been moved from section 93102.13 (j) to this 

section 93102.4(c). It has also been modified.] 

 

(1) Notification of Construction Reports. 

(A) No person may construct or modify a facility, such that it becomes 

a facility subject to this section 93102, without submitting a 

notification of construction or modification to the permitting 

agency and receiving approval in advance to construct or modify 

the facility. 

(B) The contents of the Notification of Construction Report shall 

include the information contained in Appendix 4.

(2) Alternative Notification Requirements: Instead of complying 

with the requirements in subpart paragraph (e)(1)(A) of this 

subsection, a facility may fulfill these requirements by 

complying with the permitting agency's “New Source Review” 

requirements, provided similar information is obtained. 
19

93102.5 Requirements that Apply to Existing, Modified, and New

Hexavalent Chromium Plating or Chromic Acid Anodizing 

Facilities Beginning [Effective Date]. 

Each owner or operator of a hexavalent chromium plating or 

chromic acid anodizing facility shall comply with the following 

requirements on or after the dates specified below:

(a) Removal of Add-on Pollution Control Device(s). No add-on air

pollution control device(s) installed before [Effective Date] shall be 

removed or rendered inoperable unless it is replaced by an add-on 

air pollution control device(s) meeting an emission rate of 

0.0015 mg/amp-hr or less as measured after the add-on air pollution 

control device.

(b) Environmental Compliance Training. No later than [Two Years After 

Effective Date] and within every two years thereafter, the owner or 

operator of a facility, or personnel designated by the owner or 

operator that are responsible for maintaining environmental 

compliance, shall complete an Air Resources Board (ARB) 

Compliance Assistance Training Course. 

(1) On or after [Two Years After the Effective Date] environmental 

compliance and recordkeeping required by this section 93102 

shall be conducted only by persons who completed an ARB 

Compliance Assistance Training Course. 

(2) In the event that all persons who have completed the ARB 

training class are no longer associated with a facility, the 

owner or operator may be responsible for environmental 

compliance and recordkeeping required by this section for a 

period of time not to exceed two years. The owner or operator 

shall ensure that as soon as practicable, but not longer than 

two years, personnel complete the training specified in 

subsection 91302.5(b).

(3) Environmental compliance training conducted by the South 

Coast Air Quality Management District pursuant to Rule 1469 

shall fulfill the requirements of this subpart.

(4) Nothing in this subsection 91302.5(b) shall absolve an owner 

or operator from complying with this section 93102.
20

(c) Housekeeping Requirements. Effective [Six Months After Effective 

Date], housekeeping practices shall be implemented to reduce 

potential fugitive emissions of hexavalent chromium. At a minimum,

the following practices shall be implemented:

(1) Chromic acid powder or flakes, or other substances that may 

contain hexavalent chromium, shall be stored in a closed 

container in an enclosed storage area; 

(2) Chromic acid powder or flakes shall be transported from an 

enclosed storage area to the electroplating or anodizing 

bath(s) in a closed container; 

(3) Any liquid or solid material that may contain hexavalent 

chromium that is spilled shall be cleaned up or contained 

within one hour after being spilled.

(4)(D) Dragout from the tank(s) shall be minimized by implementing 

the following practices: 

(A) Facilities with automated lines. Drip trays shall be installed 

between tanks so that the liquid does not fall through the 

space between tanks. Trays shall be placed such that the 

liquid is returned to the tank(s).

(B) Facilities without automated lines.

1. Each electroplated or anodized part must be handled so 

that excess chromic acid is not dripped outside the 

electroplating tank. 

2. Each facility spraying down parts over the electroplating 

or anodizing tank(s) to remove excess chromic acid shall 

have a splash guard installed around the tank to 

minimize overspray and to ensure that any hexavalent 

chromium laden liquid is returned to the electroplating or 

anodizing tank.

(5) Surfaces within the enclosed storage area, open floor area, 

walkways around the electroplating or anodizing tank(s), or 

any surface potentially contaminated with hexavalent 

chromium, that accumulates or potentially accumulates dust 

shall be HEPA vacuumed, hand wiped with a damp cloth, or 

wet mopped, or shall be maintained with the use of non-toxic 

chemical dust suppressants at least once every seven days. 
21

(6) Buffing, grinding, or polishing areas within a facility shall be 

separated from the facility by installing a physical barrier. The 

barrier may take the form of plastic strip curtains.

(7) Chromium or chromium-containing wastes generated from 

housekeeping activities shall be stored, disposed of, 

recovered, or recycled using practices that do not lead to 

fugitive dust and in accordance with hazardous waste 

requirements. 

93102.6 Special Provisions that Apply Only to Facilities that Perform 

Electroplating Using a Trivalent Chromium Bath and Enclosed 

Hexavalent Chromium Electroplating Facilities. 

(a) Provisions that Apply to All Facilities that Perform Electroplating 

Using a Trivalent Chromium Bath.

(1) During tank operation, each owner or operator of an existing, 

modified, or new facility shall control chromium emissions 

discharged to the atmosphere by meeting either of the 

requirements identified below. 

 [Note: This is an existing table that has been moved from section (c)(3) of the 

existing regulation. It has not been underlined in order to make it easier to read.] 

 

Method of compliance Requirement 

add-on air pollution control equipment, 

or chemical fume suppressants, or 

mechanical fume suppressants (i.e. 

polyballs) 

< 0.01 mg/dscm (4.4x10-6 gr/dscf) 

chemical fume suppressants containing 

a wetting agent 

use wetting agent as bath ingredient 

and comply with recordkeeping and 

reporting provisions of subsections 

(h)(9) 93102.12 (i) and 

(i)(5) 93102.13 (e). 

(2) New facilities that perform electroplating using a trivalent 

chromium bath must comply with the requirements specified in 

section 93102.4 (d)(1). 

(3) An owner or operator that performs electroplating using a 

trivalent chromium bath and complying through use of a 

chemical fume suppressant containing a wetting agent shall 

not be required to comply with the requirements of sections

93102.4 (except for section 93102.4(d)(1)), 93102.7, 93102.8, 
22

93102.9 (b) through (f), 93102.10, 93102.11, 93102.12 (a) 

through (f), and 93102.12 (h). 

(b)(2) Requirements for Enclosed Hexavalent Chromium Electroplating 

Tanks.

(1) The owner or operator of a hexavalent chromium 

electroplating facility with enclosed hexavalent chromium 

plating tank(s) shall control hexavalent chromium emissions 

from the electroplating tank(s) by:

(A) Achieving a hexavalent chromium emission limitation of 

0.015 mg/dscm as measured after the add-on air pollution 

control device(s); or

(B) Using a chemical fume suppressant specified in section 

93102.8, and maintaining the surface tension of the plating 

bath solution at a value specified in section 93102.8; or

(C) Not allowing the mass rate of the total chromium to exceed 

the maximum allowable mass emission rate determined by 

using the calculation procedure specified in Appendix 7.

(2) The owner or operator of a facility with enclosed hexavalent 

chromium plating tank(s) must also comply with all 

requirements of this ATCM except for the requirements set 

forth in section 93102.4(b) and (c).

93102.7 (d) Performance Test Requirements and Test Methods. 

(a)(1) Performance test requirements. 

Any source subject to the emission standards in subsection (c)(1)(A) 

or (B), or any source electing to comply with the mg/dscm emission 

standard in subsections (c)(2) or (c)(3) shall conduct a performance 

test to demonstrate compliance with the applicable emission 

standards within 180 days after initial startup.

(1) The following facilities must conduct a performance test to 

demonstrate compliance with the hexavalent chromium 

emission rate as specified in section 93102.4: 

 

(A) Existing facilities demonstrating compliance with the 

0.0015 milligrams per ampere-hour emission limitation 

specified in Table 93102.4.
23

(B) Facilities that undergo a modification after [Effective Date].

 

(C) New facilities.

(D) Trivalent chromium plating facilities meeting the emission 

rate specified in section 93102.6 (a)(1). 

 

(2) Facilities must conduct the performance test required by this 

section 93102.7 no later than 60 days after initial start-up.

(3) The performance test must be conducted using one of the 

approved test methods specified in subsection 93102.7(c). 

The hexavalent chromium emission rate shall be multiplied by 

the facility annual permitted ampere-hour usage to determine 

the annual emissions of hexavalent chromium for the facility. 

(b)(2) Use of existing previously conducted performance test. 

A performance test conducted prior to July 24, 1997 may be used to 

demonstrate compliance provided the existing source test is 

approved by the permitting agency and the U.S. EPA.

A performance test conducted after January 1, 2000 may be used to 

satisfy the requirements of this section 93102.7 so long as all of the 

following criteria are met: 

(1) The add-on air pollution control device tested demonstrated a 

hexavalent chromium emission rate of 0.0015 mg/amp-hr or 

less for hexavalent chromium plating or chromic acid 

anodizing facilities, or 0.01mg/dscm or less for trivalent 

chromium plating facilities, and

 

(2) The performance test was approved by the permitting agency, 

and

(3) The test is representative of the add-on air pollution control

device currently in use as of [Effective Date], and 

(4) The performance test was conducted using one of the 

approved test methods specified in subsection 93102.7(c).

(c)(3) Approved test methods. 

(1)(A) Emissions testing for hexavalent and total chromium shall 

be conducted with a minimum of three test runs in 

accordance with one of the following test methods: 

 
24

(A)1. California Air Resources Board CARBTest Method 425, 

last amended July 28, 1997, (section 94135, Title 17, 

California Code of Regulations (CCR); or 

(B)2. U.S. EPA Method 306, (40 CFR 63 Appendix A) with a 

minimum of three test runs with hexavalent chromium 

option (Method 306, Section 2.2.3); or 

(C)3. South Coast Air Quality Management District 

Method 205.1, for results reported as total chromium. 

(2)(B) Smoke Test to Verify the Seal Integrity of Covers Designed to 

Reduce Chromium Emissions from Electroplating and 

Anodizing Tanks (See Appendix 5). 

(3)(C) Surface tension using a tensiometer shall be measured in 

accordance with U.S. EPA Method 306B (40 CFR 63 

Appendix A). Surface tension using a stalagmometer shall be 

measured using the procedure set forth in Appendix 8, or an 

alternative procedure approved by the permitting agency. 

(d)(4) Pre-Test protocol. Facilities Sources subject to the provisions of 

subsection (d)(1), above, 93102.7 (a) must submit a pre-test protocol 

to the permitting agency at least 60 days prior to conducting a 

performance test. The pre-test protocol shall include the 

performance test criteria of the end user and all assumptions, 

required data, and calculated targets for testing the source target 

chromium concentration, the preliminary chromium analytical data, 

and the planned sampling parameters. In addition, the pre-test 

protocol shall include information on equipment, logistics, personnel, 

and other resources necessary for an efficient and coordinated test. 

 

(e)(5) Test all emission points. Each emission point subject to the 

requirements of this regulation must be tested unless a waiver is 

granted by U.S. EPA and approved by the permitting agency. 
25

93102.8 Chemical Fume Suppressants. 

Chemical fume suppressants used to comply with sections 93102.4 and 93102.6

shall meet the criteria specified in this section 93102.8.

(a) One or more of the chemical fume suppressants listed in 

Table 93102.8 shall be used to reduce the surface tension of the 

electroplating or anodizing bath(s) below the surface tension value 

listed in Table 93102.8. The surface tension value may be measured 

using either a stalagmometer or a tensiometer. 

[Table 93102.8 is a new table. For clarity it is not shown in underline/strikeout] 

Table 93102.8: Chemical Fume Suppressants Approved for Use at 

Specified Surface Tensions 

Chemical Fume 

Suppressant and 

Manufacturer 

Stalagmometer 

Measured 

Surface Tension 

(dynes/centimeter) 

Tensiometer 

Measured Surface 

Tension 

(dynes/centimeter)

Benchbrite CR 1800® 

Benchmark Products 

< 40 < 35 

Clepo Chrome® 

MacDermid 

< 40 < 35 

Fumetrol 140® 

Atotech U.S.A. 

< 40 < 35 

 

(b) Alternative chemical fume suppressants. Chemical fume 

suppressants not listed in Table 93102.8 may be used upon approval 

by the Executive Officer. The Executive Officer shall approve the use 

of an alternative chemical fume suppressant if the following criteria 

are met:

(1) The chemical fume suppressant has been performance tested 

in a hexavalent chromium electroplating or anodizing bath and 

demonstrated to reduce the hexavalent chromium emissions 

below 0.01 milligrams per ampere hour; and

(2) In the performance testing, the hexavalent chromium emission 

rate of 0.01 milligrams per ampere-hour was achieved under 

conditions in which the surface tension did not exceed 

45 dynes/cm, as measured by a stalagmometer or 

35 dynes/cm, as measured by a tensiometer.

(c) A chemical fume suppressant that is listed in subsection 93102.8(a)

or that has been approved under subsection 93102.8(b) may no 
26

longer be used if the Executive Officer determines that the chemical 

fume suppressant is no longer able to reduce the hexavalent 

chromium emission rate below 0.01 milligrams per ampere-hour 

under conditions in which the surface tension does not exceed 

45 dynes/cm, as measured by a stalagmometer or 35 dynes/cm, as 

measured by a tensiometer.

 

93102.9 (e) Parameter Monitoring Requirements. 

(a)(1) Ampere-hours. Each electroplating or anodizing tank or group of 

electroplating or anodizing tanks shall have installed a continuous 

recording, non resettable, ampere-hour meter that operates on the 

electrical power lines connected to the tank or group of tanks. A 

separate meter shall be hard-wired for each rectifier. 

(b)(2) Pressure drop. The owner or operator shall continuously monitor the 

pressure drop across an add-on control device such as a composite 

mesh-pad (CMP), packed-bed scrubber (PBS), a CMP/PBS, fiberbed mist eliminator, and a High Efficiency Particulate Air Arrestor

(HEPA) filter with a mechanical gauge. The gauge shall be located 

so that it can be easily visible and in clear sight of the operation or 

maintenance personnel. The pressure drop shall be maintained 

within ±1 +2 inches of water of the value established during the 

performance test to demonstrate compliance with the emission 

limitation for CMP, PBS, a CMP/PBS, and a fiber-bed mist eliminator. 

The pressure drop shall be maintained within - 1⁄2 times to +2 times 

the inches of water of the value established during the performance 

test to demonstrate compliance with the emission limitation for HEPA 

filters. 

 

(c)(3) Inlet velocity pressure. The owner or operator shall continuously 

monitor the inlet velocity pressure of a packed-bed scrubber with a 

mechanical gauge. The gauge shall be located so that it can be 

easily visible and in clear sight of the operation or maintenance 

personnel. The inlet velocity pressure shall be maintained within 

 + 10 percent of the value established during the performance test to 

demonstrate compliance with the emission limitation. 

(d)(4) Surface tension. The owner or operator shall measure and monitor 

the surface tension of the chrome electroplating or chromic acid

anodizing tank bath(s) that contains a wetting agent with either a 

stalagmometer using the procedure in Appendix 8 of this section 

93102 or a procedure approved by the permitting agency, or with a 

tensiometer using U.S. EPA Method 306B (40 CFR part 63, 

Appendix A). The surface tension shall be maintained at or below 

the value required by subsection (c)(2) 93102.8. Surface tension 
27

shall be measured daily for 20 operating days, and weekly thereafter 

as long as there is no violation of the surface tension requirement. If 

a violation occurs, the measurement frequency shall return to daily 

for 20 operating days, and weekly thereafter. 

 

(e)(5) Foam blanket thickness. The owner or operator shall monitor the 

foam blanket thickness across the surface of the chrome

electroplating or chromic acid anodizing bath tank. The foam blanket 

thickness shall be maintained consistent with the requirements 

established during the performance test to demonstrate compliance 

with the emission limitation. Foam thickness shall be measured 

hourly for 15 operating days, and daily thereafter as long as there is 

no violation of the foam thickness requirement. If a violation occurs, 

the measurement frequency shall return to hourly for 15 operating 

days, and daily thereafter. 

 

(f)(6) Polyballs or similar m Mechanical fume suppressants. The owner or 

operator shall visually inspect the chrome electroplating or chromic 

acid anodizing tank bath for coverage comparable to the coverage 

during the performance test daily. 

91302.10 (f) Inspection and Maintenance Requirements. 

(a)(1) Hard and decorative chrome Hexavalent chromium electroplating,

and chromic acid anodizing operations facilities using add-on air 

pollution control equipment shall comply with the applicable 

inspection and maintenance requirements listed in 

Table 93102.10 (f )(1). 

 Table 93102.10 (f)(1) -- Summary of Inspection and Maintenance 

Requirements for Sources Using Add-on Air Pollution Control Devices

 

Control 

Technique/Equipment 

Inspection and Maintenance 

Requirements 

Frequency 

Composite mesh-pad 

(CMP) system.,

Packed-bed scrubber 

(PBS), or PBS/CMP

1. Visually inspect device to ensure 

that there is proper drainage, no 

unusual chromic acid buildup on the 

pads, and / or packed beds and no 

evidence of chemical attack that affects 

the structural integrity of the device. 

1. 1/quarter. 
28

2. Visually inspect back portion of the 

mesh pad closest to the fan to ensure 

there is no breakthrough of chromic 

acid mist and/or back portion of the 

chevron mist eliminator to ensure it is 

dry and there is no breakthrough of 

chromic acid mist. 

2. 1/quarter. 

3. Visually inspect ductwork from tank 

to the control device to ensure there 

are no leaks. 

3. 1/quarter. 

4. Perform washdown of the composite 

mesh-pads in accordance with 

manufacturer's recommendations

and/or add fresh makeup water to the 

packed bed when it is needed. 

4. Per 

manufacturer. 

Packed-bed scrubber 

(PBS)

1. Visually inspect device to ensure 

there is proper drainage, no unusual 

chromic acid buildup on the packedbeds, and no evidence of chemical 

attack that affects the structural 

integrity of the device.

1. 1/quarter.

2. Visually inspect back portion of the 

chevron blade mist eliminator to ensure 

that it is dry and there is no 

breakthrough of chromic acid mist.

2. 1/quarter.

3. Same as number 3 above for CMP 

system.

3. 1/quarter.

4. Add fresh makeup water to the 

packed-bedA

4. Whenever 

makeup is 

needed.

PBS/CMP system 1. Same as for CMP system 1. 1/quarter.

2. Same as for CMP system 2. 1/quarter.

3. Same as for CMP system 3. 1/quarter.

4. Same as for CMP system 4. Per 

manufacturer.

Fiber-bed mist 

eliminatorA B

1. Visually inspect fiber-bed unit and 

prefiltering device to ensure there is 

proper drainage, no unusual chromic 

acid buildup in the units, and no 

evidence of chemical attack that affects 

the structural integrity of the devices. 

Same as number 1 for CMP/PBS.

1. 1/quarter. 

2. Visually inspect ductwork from tank 

or tanks to the control device to ensure 

there are no leaks. Same as number 3 

for CMP/PBS.

2. 1/quarter. 
29

3. Perform washdown of fiber elements 

in accordance with manufacturer's 

recommendations. Same as number 4 

for CMP/PBS.

3. Per 

manufacturer. 

High Efficiency 

Particulate Air

Arrestor (HEPA) filter 

1. Look for changes in the pressure 

drop. 

2. Replace HEPA filter. 

1. 1/week.

2. Per 

manufacturer's 

specifications 

or permitting 

agency's 

requirement. 

Chromium Tank 

Covers 

[facilities complying 

with subsection 

93102.6(b)

1. Drain the air-inlet (purge air) valves 

at the end of each day that the tank is 

in operation. 

1. 1/day. 

2. Visually inspect access door seals 

and membranes for integrity. 

2. 1/week. 

3. Drain the evacuation unit directly 

into the plating tank or into the rinse 

tanks (for recycle into the plating tank). 

3. 1/week. 

4. Visually inspect membranes for 

perforations using a light source that 

adequately illuminates the membrane 

(e.g., Grainger model No. 6X971 

Fluorescent Hand Lamp). 

4. 1/month. 

5. Visually inspect all clamps for proper 

operation; replace as needed. 

5. 1/month. 

6. Clean or replace filters on 

evacuation unit. 

6. 1/month. 

7. Visually inspect piping to, piping 

from, and body of evacuation unit to 

ensure there are no leaks and no 

evidence of chemical attack. 

7. 1/quarter. 

8. Replace access door seals, 

membrane evacuation unit filter, and 

purge air inlet check valves in 

accordance with the manufacturer's 

recommendations. 

8. Per 

manufacturer. 
30

Pitot tube Backflush with water, or remove from 

the duct and rinse with fresh water. 

Replace in the duct and rotate 180 

degrees to ensure that the same zero 

reading is obtained. Check pitot tube 

ends for damage. Replace pitot tube if 

cracked or fatigued. 

1/quarter. 

Ampere-hour meter Install and maintain per manufacturer's 

specifications.

Per 

manufacturer. 

Stalagmometer/ 

Tensiometer

Calibrate and maintain per 

manufacturer’s specifications.

Per 

manufacturer.

A

 Horizontal packed-bed scrubbers without continuous recirculation must add 

make-up water to the top of the packed-bed.

AB

Inspection and maintenance requirements for the control device installed 

upstream of the fiber-bed mist eliminator to prevent plugging do not apply as long 

as the inspection and maintenance requirements for the fiber-bed unit are 

followed. 

(2) Hard and decorative chrome electroplating, and chromic acid anodizing 

operations using chemical fume suppressants (i.e. wetting agent, foam) or 

mechanical fume suppressants (i.e. polyballs) shall comply with the 

applicable inspection and maintenance requirements in Table (f)(2).

Note: Table (f)(2) is proposed for deletion

Table (f)(2) -- Summary of Inspection and Maintenance Requirements for 

Sources Using Chemical or Mechanical Fume Suppressants

Equipment Inspection and 

Maintenance 

Requirement for 

Monitoring Equipment

Frequency

Ampere-hour meter Install and maintain per 

manufacturer's 

specifications

Per manufacturer

Stalagmometer/ 

Tensiometer

Calibrate and maintain 

per manufacturer’s 

specifications

Per manufacturer

(b) Add-on air pollution control device(s) that is custom designed for a 

specific operation shall develop operating and maintenance 

requirements. The requirements shall be submitted to the permitting 

agency for review and approval. The requirements and frequency of 

inspection must be sufficient to ensure compliance. 
31

93102.11 (g) Operation and Maintenance Plan (O & M plan)

Requirements. 

(a)(1) Prepare the O & M plan. The owner or operator subject to the 

inspection and maintenance requirements of subsections

93102.10(a) and (b) (f)(1) shall prepare an operation and 

maintenance plan. For major sources, the plan shall be incorporated 

by reference into the source's title V permit. The plan shall 

incorporate the inspection and maintenance requirements for that 

device or monitoring equipment, as identified in Table 93102.10 (f)(1)

or subsection 93102.10 (b) of this section and include the following 

elements: 

(1)(A) A standardized checklist to document the operation and 

maintenance of the facility source, the add-on air pollution 

control device, and the process and control system monitoring 

equipment; and 

(2)(B) Procedures to be followed to ensure that equipment is 

properly maintained. [To satisfy the inspection and 

maintenances requirements of this subsection, the owner or 

operator may use applicable standard operating procedure 

(SOP) manuals, Occupational Safety and Health 

Administration (OSHA) plans, or other existing plans, provided 

the alternative plans meet the requirements of this 

subsection.] 

(b)(2) Retain the O & M plan. The owner or operator shall keep the written 

operation and maintenance plan on record after it is developed to be 

made available for inspection, upon request, during normal working 

hours. 

(c)(3) Changes to the O & M plan. Any changes made by the owner or 

operator should be documented in an addendum to the plan. In 

addition, the owner or operator shall keep previous (i.e., superseded) 

versions of the operation and maintenance plan on record to be 

made available for inspection, upon request, during normal working 

hours, for a period of 5 years after each revision to the plan. 

(d)(4) Revisions to the O & M plan to address breakdowns. The operation 

and maintenance plan shall be revised as necessary to minimize 

breakdowns. 

93102.12 (h) Recordkeeping Requirements.
32

(a)(1) Inspection records for sources using add-on control air pollution 

control devices. The owner or operator shall maintain inspection 

records to document that the inspection and maintenance 

requirements of subsection (f) 93102.10 and Table (f)(1) 93102.10, 

and the provisions of the operation and maintenance plan required by 

subsection (g) 93102.11 have been met. The record can take the 

form of a checklist and shall identify: 

(1)(A) the device inspected, 

(2)(B) the date and time of inspection, 

(3)(C) a brief description of the working condition of the device during 

the inspection, 

(4)(D) maintenance activities performed on the components of the air 

pollution control system (i.e. duct work replacement, filter pad 

replacement, fan replacement, etc), and 

(5)(E) actions taken to correct deficiencies found during the 

inspection. 

(2) Inspection records for sources using chemical fume suppressants (i.e. 

wetting agent, foam) or mechanical fume suppressants (i.e. polyballs).

The owner or operator shall maintain inspection records to document that 

the inspection and maintenance requirement of subsection (f)(2) and 

Table (f)(2) have been met. The record can take the form of a checklist.

(b)(3) Performance test records. The owner or operator shall maintain test 

reports documenting the conditions and results of all performance 

tests. 

(c)(4) Monitoring data records. The owner or operator shall maintain 

records of monitoring data required by subsection 93102.9 (e) that 

are used to demonstrate compliance with the standard including the 

date and time the data are collected. 

(1)(A) Cumulative rectifier usage records. Record the actual 

cumulative rectifier usage expended during each month of the 

reporting period, and the total usage expended to date. 

(2)(B) Pressure drop. The owner or operator shall record the 

pressure drop once a week. 

(3)(C) Inlet Velocity Pressure. The owner or operator shall record 

the inlet velocity pressure weekly. 
33

(4)(D) Surface tension. The owner or operator shall record the 

surface tension daily for 20 operating days, and weekly 

thereafter as long as there is no violation of the surface 

tension requirement. If the surface tension exceeds 45 

dynes/cm levels specified in section 93102.8, the owner or 

operator shall again record the surface tension daily for 

20 operating days, and weekly thereafter. 

(5)(E) Foam thickness. The owner or operator shall record the foam 

thickness hourly for 15 operating days, and daily thereafter as 

long as there is no violation of the foam thickness requirement. 

If a violation occurs, the measurement frequency shall return 

to hourly for 15 operating days, and daily thereafter. 

(d)(5) Breakdown records. The owner or operator shall maintain records of 

the occurrence, duration, and cause (if known) and action taken on 

each breakdown. 

(e)(6) Records of excesses. The owner or operator shall maintain records 

of exceedances of: the emission limitations in subsection 93102.4 (c), 

the monitoring parameter values established under subsection (e)

93102.9, or any site-specific operating parameters established for 

alternative equipment. The records shall include the date of the 

occurrence, the duration, cause (if known), and, where possible, the 

magnitude of any excess emissions. 

(f)(7) Records demonstrating facility size. Facility size for determining the 

applicable emission limitation in subsection 93102.4 (a) is determined 

by the maximum cumulative potential rectifier capacity. However, a 

facility with a maximum cumulative potential rectifier capacity of 

60 million amp-hr/yr or more may, at the option of the owner or 

operator, be considered small or medium if the actual cumulative 

rectifier usage is less than 60 million amp-hr/yr as demonstrated by 

using either of the following procedures: 

(1)(A) Annual actual cumulative rectifier capacity. Show by records 

that the facility's previous annual actual cumulative rectifier 

capacity was less than 60 million amp-hr/yr, by using 

nonresettable ampere-hour meters and keeping monthly 

records of actual ampere-hour capacity for each 12-month 

rolling period following the compliance date. The actual 

cumulative rectifier capacity for the previous 12-month rolling 

period shall be tabulated monthly by adding the capacity for 

the current month to the capacities for the previous 11 months; 

or 
34

(2)(B) Maximum cumulative potential rectifier usage limit. By 

accepting a limit on the maximum cumulative potential rectifier 

usage of a hard chromium electroplating facility through a 

title V permit condition or a permitting agency operating permit 

condition and by maintaining monthly records in accordance 

with subsection 93102.12(c)(1) (h)(4)(A) to demonstrate that 

the limit has not been exceeded. 

(g) Records of annual ampere-hour use. Facilities shall maintain 

monthly records of total ampere-hour use per calendar year. The 

record shall be submitted to the permitting agency as part of their 

Initial and Ongoing Compliance Status Reports as specified in 

Appendix 2 and 3. 

(h)(8) Records of chemical fume suppressant additions. For facilities

sources using chemical fume suppressants to comply with the 

standards or requirements, the owner or operator shall maintain 

records of the date, time, approximate volume, and product 

identification of the chemical fume suppressants that are is added to 

the electroplating or anodizing bath. 

 

(i)(9) Records of trivalent chromium process bath components. For 

facilities sources complying with subsection 93102.6(a) (c)(3) using 

the trivalent chromiume baths process, the owner or operator shall 

maintain records of the bath components purchased, with the wetting 

agent clearly identified as a bath constituent contained in one of the 

components. 

(j)(10) New/modified source review information. The owner or operator 

shall maintain records supporting the notifications and reports 

required by the permitting agency's new source review provisions 

and/or subsection 93102.4(e) (j). 

 

(k) Housekeeping records. The owner or operator shall maintain records 

demonstrating compliance with housekeeping requirements, as 

required by section 93102.5, including the dates on which specific 

activities were completed, and records showing that chromium or 

chromium-containing wastes have been stored, disposed of, 

recovered, or recycled using practices that do not lead to fugitive dust

emissions. 

(l)(11) Records retention. All records shall be maintained for five years, at 

least two years on site. 
35

93102.13 (i) Reporting Requirements.

 

(a)(1) Performance test documentation. 

(1)(A) Notification of performance test. 

(A)1. The owner or operator of a facility source shall notify the 

permitting agency of his or her intention to conduct a 

performance test at least 60 calendar days before the 

performance test is scheduled. 

 

(B)2. The provisions in subsection 93102.13(a)(1)(A) (i)(1)(A)1., 

above, do not apply if the performance test was conducted 

prior to July 24, 1997, was used to demonstrate 

compliance with 93102.4(a) or 93102.6(a), and was 

approved by the permitting agency and the U.S. EPA. 

(2)(B) Reports of performance test results. The owner or 

operator shall report performance test results to the 

permitting agency. Reports of performance test results 

shall be submitted no later than 90 days following the 

completion of the required performance test, and shall be 

submitted as part of the notification of compliance status 

required by subpart (b) paragraph (2) of this subsection. 

(3)(C) The content of performance test reports shall contain the 

information is identified in Appendix 1. 

(b)(2) Initial compliance status report. An initial compliance status report is 

required each time that a facility source becomes subject to the 

requirements of this section. The owner or operator shall submit to 

the permitting agency an initial compliance status report, signed by 

the responsible official who shall certify its accuracy, attesting to 

whether the facility source has complied with this rule. 

(1)(A) Initial compliance status report due date. 

1. For sources required to conduct a performance test, the initial 

compliance status report shall be submitted to the permitting 

agency no later than 90 calendar days following completion of 

the compliance demonstration.

 

2. For sources that are not required to complete a performance 

test, the initial compliance status report shall be submitted to 

the permitting agency no later than 30 days after the effective 
36

date of this rule for existing facilities sources, or at start-up for 

new facilities sources. 

(2)(B) The content of the initial compliance status report shall contain 

the information is identified in Appendix 2. 

(c)(3) Ongoing compliance status reports. The owner or operator shall 

submit a summary report to the permitting agency to document the 

ongoing compliance status. 

(1)(A) Frequency of o Ongoing compliance status reports. 

1. The report shall be submitted to the permitting agency on or 

before February 1 annually for major all facilities sources and 

shall include information for the preceding calendar year 

(January 1 through December 31). 

2. The report shall be prepared annually and made available to 

the permitting agency upon request for area sources.

(2)(B) The content of ongoing compliance status reports shall include 

the information is identified in Appendix 3. 

(d)(4) Reports of breakdowns. The owner or operator shall report 

breakdowns as required by the permitting agency's breakdown rule. 

 

(e)(5) Reports associated with the trivalent chromium process baths using a 

wetting agent. 

(1) Facilities currently using the trivalent chromium process. 

(A) Owners or operators electroplating with the trivalent 

chromium process baths using a wetting agent are not 

subject to subsections (a), (b), and (c) paragraphs (1) 

through (3) of this subsection 93102.13, but must instead

shall submit to the permitting agency the following 

information reports: 

(A) Sources currently using trivalent chromium. N no later 

than 30 days after the effective date of this rule: , the 

owner or operator shall submit a notification of compliance 

status that contains: 

 

1. The name and address of each facility source subject to 

this paragraph; 

 
37

2. A statement that a trivalent chromium process that 

incorporates a wetting agent will be used to comply with 

these requirements; and 

 

3. The list of bath components that comprise the trivalent 

chromium bath, with the wetting agent clearly identified. 

(B) An owner or operator electroplating with the trivalent 

chromium process and complying with the emission 

limitation option in subsection 93102.6 (a) shall submit the 

information contained in subsections (a), (b), and (c) of this 

section 93102.13. The report shall be submitted in 

accordance with the schedules identified in those 

paragraphs.

(2)(B) Facilities sources changing to the trivalent chromiume

process. Within 30 days of a change to the trivalent chromium 

electroplating process, the owner or operator shall submit to 

the permitting agency a report that includes: 

(A) Facilities electroplating with the trivalent chromium process 

using a wetting agent shall submit the following 

information: 

1. The name and address of each facility subject to this 

paragraph; and

2. A statement that a trivalent chromium process that 

incorporates a wetting agent will be used to comply with 

these requirements; and

3. The list of bath components that comprise the trivalent 

chromium bath, with the wetting agent clearly identified; 

and

4.1. A description of the manner in which the process has 

been changed. and the emission limitation, if any, now 

applicable to the source; and 

(B) Facilities electroplating with the trivalent chromium process 

and complying with the emission limitation option in 

93102.6 (a) shall submit the information contained in 

subsections (a), (b), and (c) of this subsection 93102.13. 

The report shall be submitted in accordance with the 

schedules identified in those paragraphs.
38

2. The notification and reporting requirements of paragraphs (1), 

(2), and (3) of this subsection, if the source complies with the 

emission limitation option, or paragraph (5) of this subsection, if 

the source uses a wetting agent to comply. The report shall be 

submitted in accordance with the schedules identified in those 

paragraphs.

(f)(6) Adjustments to the timeline for submittal and format of reports. A 

permitting agency may adjust the timeline for submittal of periodic 

reports, allow consolidation of multiple reports into a single report, 

establish a common schedule for submittal or reports, or accept 

reports prepared to comply with other State or local requirements. 

Prior to allowing an adjustment, the permitting agency must find that 

the adjustment will provide the same information and will not alter the 

overall frequency of reporting. 

(j) New and Modified Sources.

[Note: this subsection has been moved to section 93102.4 and has been 

modified.] 

 

(1) Notification of Construction Reports. After the effective date of this 

rule no person may construct or modify a source, such that it becomes a 

source subject to this section, without submitting a notification of 

construction or modification to the permitting agency and receiving 

approval in advance to construct or modify the source. The contents of the 

Notification of Construction Report is contained in Appendix 4.

(2) New Source Review Rules. In lieu of complying with the 

requirements in paragraph (j)(1) of this subsection, a facility may fulfill 

these requirements by complying with the permitting agency's new source 

review rule or policy, provided similar information is obtained. 

93102.14 (k) Procedure for Establishing Alternative Requirements. 

(a)(1) Request Approval of an Alternative Requirement. Any person may 

request approval of an alternative requirement. The person seeking 

such approval shall submit the proposed alternative requirement to 

the permitting agency for approval. The request must include the 

proposed alternative requirement, the reason for requesting the 

alternative requirement, and information demonstrating that the 

criteria for approval identified in Table 93102.14 (k)(1) is are met. 

(b)(2) Approval of an Alternative Requirement. A permitting agency may 

approve an alternative requirement if it determines that application of 

the alternative requirement meets the criteria for approval identified in 
39

Table 93102.14 (k)(1), and the permitting agency has received 

concurrence by the ARB and U.S. EPA where concurrence is 

required. 

(c)(3) Concurrence for an Alternative Requirement. For those requirements 

identified in Table 93102.14 (k)(1) as requiring concurrence by the 

U.S. EPA and ARB, the permitting agency shall submit the alternative 

requirement to the concurring agency prior to final action by the 

permitting agency. 

(d)(4) Reports of Approved Alternative Requirements to U.S. EPA. The 

permitting agency shall provide the U.S. EPA and ARB with copies of 

all approved alternative requirements. The information shall be 

provided at a mutually agreed upon frequency. 

(e)(5) Approval Criteria. Nothing in this section prohibits the permitting 

agency from establishing approval criteria more stringent than that 

required in Table 93102.14 (k)(1). 

(f)(6) Alternatives Approved by U.S. EPA. Waivers obtained from U.S. 

EPA prior to the effective date [Effective Date] of this regulation shall 

remain in effect until the effective dates of the requirements in 

subsection 93102.4(b) become effective.

Table 93102.14 (k)(1) -- Requirements for Approval of Alternatives 

 

Subsection Requirement Criteria for 

Approval 

Approving 

Agency 

Concurring 

Agency(4) (1)

(a)

93102.1

aApplicability equivalent type and 

size of facility

source regulated 

District U. S. EPA 

(c) 

93102.4

standards 

Limits and 

requirements

equivalent emission 

reductions 

District U. S. EPA,

ARB

(d)(1)

93102.7(a)

pPerformance 

test 

requirements

equivalent means 

of determining 

compliance 

District U. S. EPA 

(d)(2)

93102.7(b)

uUse of 

previously 

conducted 

existing

performance 

source tests 

Ooverall existing 

tests provide a 

similar level of 

compliance 

assurance 

District U. S. EPA 

(d)(3)

93102.7(c)

aAlternative 

test method 

provides a similar 

level of accuracy 

and precision 

District U. S. EPA 

ARB 

(d)(4)

93102.7(d)

aAmendments 

to the pre-test 

equivalent means 

of determining 

District U. S. EPA 
40

protocol compliance 

(d)(5)

93102.7(e)

tTest all 

emission points 

equivalent means 

of determining 

compliance 

District U. S. EPA 

(e)

93102.9

pParameter 

monitoring 

equivalent means 

of determining and 

assuring 

compliance 

District U. S. EPA 

(f)

93102.10

iInspection 

maintenance 

requirements 

equivalent means 

of assuring 

compliance 

District U. S. EPA 

(g)

93102.11

oOperation and 

maintenance 

plans 

equivalent means 

of assuring 

compliance 

District U. S. EPA 

(h)(1)(10)

93102.12 (a) 

through (f) and 

(h) through (j)

rRecordkeeping 

equivalent means 

of assuring 

compliance 

District U. S. EPA 

(h)(11)

93102.12(l)

rRetention of 

records 

assure historical 

records available 

for up to 5 years 

District U. S. EPA 

(i)

93102.13

rReporting equivalent means 

of assuring 

compliance 

District U. S. EPA 

1. combined hexavalent or total chrome emissions from hard chrome plating operations 

2. maximum cumulative potential rectifier capacity or usage limit 

3. "Option 2" is an alternative emission limitation for small and medium facilities that 

elect to demonstrate compliance with both a mg/amp-hr and a mg/dscm requirement 

4. 1. U.S. EPA or the implementing agency in accordance with any delegation of 

authority to approve alternatives from the U.S. EPA. 

93102.15 Requirements Relating to Chromium Plating Kits.

(a) Except as provided in subsection (b), no person shall sell, supply, 

offer for sale, or manufacture for sale in California, any chromium 

plating or chromic acid anodizing kit.

(b) The provisions of subsection (a) do not apply to any person that sells, 

supplies, offers for sale, or manufactures for sale in California a 

chromium plating or chromic acid anodizing kit to the owner or 

operator of a permitted facility at which chromium plating or chromic 

acid anodizing is performed.

(c) No person shall use a chromium plating or chromic acid anodizing kit 

to perform chromium electroplating or chromic acid anodizing unless 
41

these activities are performed at a permitted facility that complies 

with the requirements of this ATCM.

(d) For the purposes of this section, “chromium electroplating or chromic 

acid anodizing kit” means chemicals and associated equipment for 

conducting chromium electroplating or chromic acid anodizing 

including, but not limited to, internal and external tank components. 

93102.16 This section 93102.16 contains Appendices 1 through 8 to the 

ATCM for Chromium Plating and Chromic Acid Anodizing Facilities.
42

Appendix 1 - Content of Performance Test Reports 

Performance test reports required by section 93102.13 shall contain the following 

information: 

1. A brief process description; 

2. Sampling location description(s); 

3. A description of sampling and analytical procedures and any modifications 

to standard procedures; 

4. Test results in mg/amp-hr; 

5. Quality assurance procedures and results; 

6. Records of operating conditions during the test, preparation of standards, 

and calibration procedures; 

7. Original data for field sampling and field and laboratory analyses; 

8. Documentation of calculations; and 

9. Any other information required by the test method. 

 

Note: Test reports consistent with the provisions of California Air Resources 

Board ARB Method 425 will fulfill the above performance test report content 

requirement. 
43

Appendix 2 - Content of Initial Compliance Status Reports

Initial compliance status reports required by subsection 93102.13(b) shall contain 

the following information: 

1. The applicable emission limitation and the methods that were used to 

determine compliance with this limitation; 

2. If a performance test is required, the test report documenting the results of 

the performance test, which contains the elements listed in Appendix 1; 

3. The type and quantity of hazardous air pollutants emitted by the source 

reported in mg/dscm or mg/hr for decorative and anodizing operations. (If 

the owner or operator is subject to the construction and modification 

provisions of subsection (j) and had previously submitted emission 

estimates, the owner or operator shall state that this report corrects or 

verifies the previous estimate.) For sources not required to conduct a 

performance test, the surface tension measurement may fulfill this 

requirement; 

4. For each monitored parameter for which a compliant value is to be 

established under subsection (e) the specific operating parameter value, 

or range of values, that corresponds to compliance with the applicable 

emission limit; 

5. The methods that will be used to determine continuous compliance, 

including a description of monitoring and reporting requirements, if 

methods differ from those identified in this section; 

6. A description of the air pollution control technique for each emission point; 

7. A statement that the owner or operator has completed and has on file the 

operation and maintenance plan as required by subsection (g); 

1. Company Information: Facility name, address, owner/operator name, 

telephone number, the measured distance from the edge of the facility that 

is nearest to the sensitive receptor to the property boundary of the sensitive 

receptor that is within 150 meters;

2. The applicable requirements from section 93102.4 and the methods that 

were used to determine compliance. A description of the air pollution 

control technique for each emission point;

3. If a facility is using add-on controls to comply provide the following:

a) Description of add-on controls and a performance test report 

documenting the results of the performance test, which contains the 

elements listed in Appendix 1;
44

b) The actual hexavalent chromium emissions of the facility in pounds per 

year calculated by multiplying the emission rate with the actual amperehours for the preceding calendar year.

c) For monitored parameters 93102.9 (b) and (c), the specific operating 

parameter value, or range of values, that corresponds to compliance 

with the applicable emission limit; 

d) A statement that the owner or operator has completed and has on file 

the operation and maintenance plan as required by subdivision (j);

4. If a facility is using in-tank controls to comply, provide the following:

a) Description of in-tank controls including name of in tank controls, name 

of chemical fume suppressant, surface tension of the electroplating or 

anodizing bath;

 

b) For monitored parameters 93102.9 (d), (e), and (f) the specific operating 

parameter value where applicable, or range of values, that corresponds 

to compliance;

5. The actual cumulative ampere-hour usage expended during the preceding 

calendar year.

6.8. If the owner or operator is determining facility size based on actual 

cumulative rectifier usage, records to support that the facility is small or 

medium. For existing facilities sources, records from any 12-month period 

preceding the compliance date shall be used or a description of how 

operations will change to meet a small or medium designation shall be 

provided. For new facilities sources, records of projected rectifier usage for 

the first 12-month period of tank operation shall be used; 

7. A statement that the owner or operator, or personnel designated by the 

owner or operator, has completed Environmental Compliance Training 

pursuant to 93102.5 (b). 

8.9. A statement by the owner or operator as to whether the facilities source has 

complied with the provisions of this sections 93102 through 93102.16.
45

Appendix 3 - Content of Ongoing Compliance Status Reports

Ongoing compliance status reports required by section 93102.13(c) shall contain 

the following information: 

1. The company name and address of the source; 1. Company 

Information: facility name, address, owner/operator name, telephone 

number, the measured distance from the edge of the facility that is 

nearest to the sensitive receptor to the property boundary of the 

sensitive receptor that is within 150 meters

2. An identification of the operating parameter that is monitored for 

compliance determination, as required by subsection (e); 

3. 2. The relevant emission limitation requirements for the facility source, 

and the operating parameter value, or range of values, that correspond 

to compliance with this emission limitation as specified in the notification 

of initial compliance status required by Appendix 2; 

4. The beginning and ending dates of the reporting period; 

5. A description of the type of process performed in the source; 

6. 3. The actual cumulative rectifier ampere-hour usage expended during 

the reporting period, on a month-by-month basis, for the reporting period 

January 1 through December 31; if the source is a hard chromium 

electroplating tank; 

4. The actual hexavalent chromium emissions of the facility during the 

reporting period in pounds per year calculated by multiplying the emission

rate with the actual ampere-hour usage for the reporting period;

7. 5. A summary of any excess emissions or exceeded monitoring 

parameters as identified in the records required by subsection (h)(6)

93102.12(e) ; 

8. 6. A certification by a responsible official that the inspection and 

maintenance requirements in subsection 93102.10 (f) were followed in 

accordance with the operation and maintenance plan for the facility

source; 

9. 7. If the operation and maintenance plan required by subsection

93102.11 (g) was not followed, an explanation of the reasons for not 

following the provisions, an assessment of whether any excess 

emissions and/or monitoring parameter excesses are believed to have 

occurred, and a copy of the record(s) required by subsection 

93102.12(a) (h)(1) documenting that the operation and maintenance 

plan was not followed; 

10. 8. A description of any changes in monitoring, processes, or controls 

since the last reporting period; 

9. A statement that the owner or operator, or personnel designated by the 

owner or operator, has, within the last 2 years, completed Environmental 

Compliance Training pursuant to 93102.5(b)
46

11.10. The name, title, and signature of the responsible official who is 

certifying the accuracy of the report; and 

12.11. The date of the report. 

 

Appendix 4 - Notification of Construction Reports

Notification of Construction Reports required by subsection 93102.4(e) shall 

contain the following information: 

1.A. The owner or operator's name, title, and address; 

2.B. The address (i.e., physical location) or proposed address of the 

facility source if different from the owner's or operator's; 

3.C. A notification of intention to construct a new facility source and 

certification that all of the criteria specified in subsection 93102.4 

(d) are met.

4. A notification of intention to or make any physical or operational 

changes to a facility source that may meet or has been determined 

to meet the criteria for a modification; 

5.D. The expected commencement and completion dates of the 

construction or modification; 

6.E. The anticipated date of (initial) startup of the facility source; 

7.F. The type of process operation to be performed (hard or decorative 

chromium electroplating, or chromic acid anodizing); 

8.G. A description of the air pollution control technique to be used to 

control emissions, such as preliminary design drawings and design 

capacity if an add-on air pollution control device is used; and 

9.H. An estimate of emissions from the facility source based on 

engineering calculations and vendor information on control device 

efficiency, expressed in units consistent with the emission limits of 

this subpart. Calculations of emission estimates should be in 

sufficient detail to permit assessment of the validity of the 

calculations. 

Note: A facility can fulfill these report content requirements by complying with the permitting 

agency's new source review rule or policy, provided similar information is obtained. 
47

Appendix 5 - Smoke Test for Chromium Tank Covers

SMOKE TEST TO VERIFY THE SEAL INTEGRITY OF COVERS DESIGNED 

TO REDUCE CHROMIUM EMISSIONS FROM ELECTROPLATING AND 

ANODIZING TANKS 

1. Applicability and Principle 

2.1.1 Applicability. This alternative method is applicable to all hard chromium 

electroplating and anodizing operations where a chromium tank cover 

is used on the tank for reducing chromium emissions. 

3.1.2 Principle. During chromium electroplating or anodizing operations, 

bubbles of hydrogen and oxygen gas generated during the process rise 

to the surface of the tank liquid and burst. Upon bursting, tiny droplets 

of chromic acid (chromium mist) become entrained in the air above the 

tank. Because the chromium tank cover completely encloses the air 

above the tank, the chromium mist either falls back into the solution 

because of gravity or collects on the inside walls of the chromium tank 

cover and runs back into the solution. A semi-permeable membrane 

allows passage of the hydrogen and oxygen out of the chromium tank 

cover. A lit smoke device is placed inside the chromium tank cover to 

detect leaks at the membrane, joints, or seals. 

3.2. Apparatus 

4.2.1 Smoke device. Adequate to generate 500 to 1000 ft3

 of smoke/20 ft2 of 

tank surface area (e.g., Model #1A=15 SECONDS from Superior 

Signal, New York). 

5. 2.2 Small container. To hold the smoke device. 

6.3. Procedure 

Place the small container on a stable and flat area at center of the 

chromium tank cover (you can use a board and place it on the buss 

bars). Place the smoke device inside the container. After lighting the 

smoke device, quickly close the access door to avoid smoke from 

escaping. Let smoke device completely burn; entire space under the 

chromium tank cover will now be filled with the smoke. Observe for 

leaks of smoke from each seal, joint, and membrane of the chromium 

tank cover. Record these observations including the locations and a 

qualitative assessment of any leaks of smoke. 

When all seals, joints, and membranes have been observed, evacuate 

the unit to remove the smoke from the chromium tank cover. 
48

Appendix 6 - Air Pollution Control or Air Quality Management District 

Breakdown Rules. 

DISTRICT RULE # RULE NAME

Amador 516 Upset and Breakdown Conditions 

Antelope 430 Breakdown Provisions 

Bay Area 1 General Provisions and Definitions 

Butte 275 Reporting Procedures for Excess Emissions 

Calaveras 516 Upset and Breakdown Conditions 

Colusa 1.13 Equipment Breakdown 

El Dorado 516 Upset and Breakdown Conditions 

Feather 

River 

9.6 Equipment Breakdown 

Glenn 95.2 Malfunction of Equipment 

Great Basin 403 Breakdown 

Imperial 111 Equipment Breakdown 

Kern 111 Equipment Breakdown 

Lake Chapter 

III, Article 

II 

Malfunction 

Lassen 2:15 Equipment Breakdown 

Mariposa 516 Upset and Breakdown Conditions 

Mendocino R1-5-540 Equipment Breakdown 

Modoc 2.12 Equipment Breakdown 

Mojave 430 Breakdown Provisions 

Monterey 

Bay 

214 Breakdown Condition 

North Coast 3-4-540 Breakdown and Violation Reporting 

North Coast 1-5-540 Equipment Breakdown 

Northern 

Sierra 

516 Upset and Breakdown Conditions 

Northern 

Sonoma 

1-5-540 Equipment Breakdown 

Placer 404 Upset Conditions Breakdown. Scheduled 

Maintenance 

Sacramento 602 Breakdown Conditions: Emergency Variance 

San Diego 98 Breakdown Conditions: Emergency Variance 

San 

Joaquin 

110 Equipment Breakdown 

San Luis 

Obispo 

107 Breakdown or Upset Conditions and 

Emergency Variances 
49

Santa 

Barbara 

505 Breakdown Conditions 

Santa 

Barbara 

506 Emergency Variances for Breakdowns 

Shasta 3:10 Excess Emissions 

Siskiyou 2.12 Equipment Breakdown (Siskiyou) 

South 

Coast 

430 Breakdown Provisions 

Tehama 4:17 Upset or Breakdown Conditions 

Tuolumne 516 Upset and Breakdown Conditions 

Ventura 32 Breakdown conditions; Emergency Variances 

Yolo 

Solano 

5.2 Upset/Breakdown Conditions: Emergency 

Variance 
50

Appendix 7 – Alternative Requirements for Enclosed Hexavalent Chromium 

Electroplating Facilities – Mass Emission Rate Calculation Procedure

Mass Emission Rate Should be calculated using the following equation:

MAMER = ETSA x K x 0.015 mg/dscm 

Where:

MAMER = the alternative emission rate for enclosed hexavalent chromium 

electroplating tanks in mg/hr.

ETSA = the hexavalent chromium electroplating tank surface area in square 

feet(ft2).

K = a conversion factor, 425 dscm/(ft2

x hr).
51

Appendix 8 – Surface Tension Procedure for a Stalagmometer

The stalagmometer must first be properly cleaned before being used for the first 

time and after a period of storage. Properly clean the stalagmometer using the 

following procedure:

1. Set up stalagmometer in stand in a fume hood.

2. Place a clean 150 mL beaker underneath the stalagmometer then fill 

with reagent grade concentrated nitric acid. Immerse bottom tip 

(approximately 1⁄2 “) of stalagmometer into the beaker.

3. Squeeze rubber bulb and pinch at the arrow up (1) position to collapse. 

Place bulb end securely on top end of stalagmometer. Carefully draw the 

nitric acid by pinching the arrow up (1) position until the level is above the 

top etched line.

4. Allow nitric acid to remain in stalagmometer for 5 minutes and then 

carefully remove the bulb allowing the acid to completely drain.

5. Fill a clean 150 mL beaker with distilled or deionized water. Using the 

rubber bulb per the instructions in Step #3, rinse and drain stalagmometer 

with deionized or distilled water until the inside is “water break” free.

6. Fill a clean 150 mL beaker with alcohol. Again using the rubber bulb 

per Step #3, rinse and drain stalagmometer twice with alcohol and allow 

the stalagmometer to dry completely.

7. Take a sample of the solution to be tested and adjust the solution to 

room temperature. Measure the specific gravity and record reading.

8. Fill a clean 150 mL beaker with solution to be tested. Immerse bottom 

end of stalagmometer into the beaker. Fill the stag per instructions in Step 

#3, making sure that the solution level is above the top etched line.

9. Raise the stalagmometer so that the bottom end is completely out of 

solution. Remove bulb and immediately place a finger on the top end of 

the stalagmometer. Carefully use the finger to bring the solution level 

down to the top etched line. Do not release finger at this time.

10. “Wipe” the excess solution on the lower tip by touching it against the

side of the beaker.

11. Release fingertip to allow solution to drain and count number of drops 

until the level reaches the bottom etched line. 
52

Calculations for Surface Tension

Surface tension (dynes/cm) = Sw * Nw * D

 N * Dw

Sw = Surface tension of water at 25oC or 77oF (72.75 dynes/cm)

Nw = water drop number etched on instrument

D = measured specific gravity (g/ml)

N = # of solution drops

Dw = water density (1.0 g/mL)

PRECAUTIONS:

1. Make sure they stalagmometer is clean (no sludge or film)

2. No chips, cracks, etc

3. Vertical placement

4. No vibration

5. 20 drops per minute rate (10 dynes/cm)

6. Performance checked with water

7. Sample at room temperature

NOTE: Authority cited: sections 39600, 39601, 39650, 39658, 39659, 39666, and 41511, 

Health and Safety Code. Reference: sections 39650, 39658, 39659, 39665, 39666, and 41511, 

Health and Safety Code; and 40 CFR Part 63 Subpart N. 
Appendix B 

Chronology of Meetings 
1

Appendix B 

Chronology of Meetings 

 Date Meeting 

January 29, 2002 Diamond Bar Stakeholder Workgroup 

July 2, 2002 Conference call with California Air Districts 

October 8, 2002 Conference call with California Air Districts 

October 16, 2002 Meeting with Chemical Manufacturer 

November 22, 2002 El Monte Stakeholder Workgroup 

November 25, 2002 San Francisco Stakeholder Workgroup 

December 17, 2002 Fresno Stakeholder Workgroup 

October, 28, 2003 

Conference call with Metal Finishing Association of 

Southern California 

November 13, 2003 Conference call with the Northern California Metal 

Finishing Association 

November 18, 2003 Conference call with California Air Districts 

December 9, 2003 Fresno Stakeholder Workgroup 

December 10, 2003 San Francisco Stakeholder Workgroup 

December 11, 2003 El Monte Stakeholder Workgroup 

January 12, 2004 Conference call with California Air Districts 

November, 7, 2005 Meeting with SCAQMD staff in Diamond Bar 

November 16, 2005 Conference call with California Air Districts 

January, 2006 Conference calls with Chemical Manufacturers 

April 13, 2006 Conference call with California Air Districts 

May 3, 2006 

Conference call with Metal Finishing Association of 

Southern California 

May 10, 2006 Northern California Chrome Stakeholder Workgroup 

May 12, 2006 El Monte Stakeholder Workgroup 

June 8, 2006 Environmental Stakeholder Teleconference 

June 22, 2006 California Air Districts Teleconference 

June 26, 2006 Chrome-plating Industry Teleconference 

June 27, 2006 Diamond Bar Public Workshop 

June 30, 2006 Northern California Chrome Public Workshop 















Appendix F 

Results of Emission Testing Program
Phase I – Test 1 & 2 Facility 1 

1

Table VI-1 

Sigma Plating Company, Inc. Hoist Line Decorative Chromium Plating Tank 

Sampling Dates – January 9, 10, & 17, 2003 

Sampling Location Plating Tank Exhaust 

Sample Number SI-02 SI-03 SI-07 

Sampling Date 1/9/2003 1/10/2003 1/17/2003 

 

Plating Tank Data 

Totalizer (amp-hours) 12,468 9,080 4,634 

Production Rate (amp-hrs/hr) 2,078 1,892 1,655 

 

Stack Data 

Temperature ( 0F) 69 63 67 

Velocity (ft/sec) 57 53 58 

Static Pressure ("H20) -4.4 -4.4 -4.4 

Stack Area (sq. ft.) 0.994 0.994 0.994 

Flow Rate (DSCFM) 3300 3100 3400 

Moisture (% of v/v) 0.7 0.9 0.1 

 

Sampling Data 

Sampling Time (minutes) 360 288 168 

Sample Volume (DSCF) 428.10 326.64 191.63 

Chromium Data (ng/sample) 

 Total Chromium 3.5E+6 2.8E+6 1.9E+5 

 Hexavalent Chromium 1.4E+6 6.8E+5 7.8E+4 

Isokinetic Rate (%) 104 106 98 

 

EMISSIONS 

Concentration (ng/dscf) 

 Total Chromium 8.2E+3 8.6E+3 1.0E+3 

 Hexavalent Chromium 3.3E+3 2.1E+3 4.1E+3 

Emission Rate (mg/hr) 

 Total Chromium 1600 1600 210 

 Hexavalent Chromium 660 390 83 

Emissions Factors 

 (mg/amp-hr)1

 Total Chromium 0.77 0.85 0.13 

 Hexavalent Chromium 0.32 0.21 0.05 

DSCF means dry standard cubic feet. Standard conditions are 68 F and 29.92 inches Hg. 

DSCFM means dry standard cubic feet per minute.

1 Emissions Factors (mg/amp-hr) = Emission Rate (mg/hr) / Plating Tank Production Rate (amp-hrs/hr) 
Phase I – Test 1 & 2 Facility 1 

2

Table VI-2 

Sigma Plating Company, Inc. Hoist Line Decorative Chromium Plating Tank Mist Eliminator 

Sampling Dates – January 14, 15, & 16, 2003

Sampling Location Upstream 

of Mist 

Eliminator

Downstream 

of Mist 

Eliminator 

Upstream 

of Mist 

Eliminator

Downstream 

of Mist 

Eliminator 

Upstream 

of Mist 

Eliminator

Downstream 

of Mist 

Eliminator 

Test Number SI-041

 SO-043SI-05 SO-05 SI-06 SO-06 

Sampling Date 1/14/2003 1/15/2003 1/16/2003 

Plating Tank Data 

Totalizer (amp-hrs) 6,0593

8,874 9,002 

Production Rate (amp-hrs/hr) 1,010 1,479 1,500 

Stack Data 

Temperature ( 0F) 69 67 72 72 76 72 

Velocity (ft/sec) 59 66 59 65 59 61 

Static Pressure ("H20) -4.4 -7.4 -4.4 -7.4 -4.4 -7.4 

Stack Area (sq. ft.) 0.994 0.994 0.994 0.994 0.994 0.994 

Flow Rate (DSCFM) 3400 3800 3400 3700 3400 3500 

Moisture (% of v/v) 1.0 1.0 0.6 0.8 0.2 0.5 

Sampling Data 

Sampling Time (minutes) 360 360 360 360 360 360 

Sample Volume (DSCF) 238.39 280.24 253.58 273.84 249.54 257.45 

Chromuim Data (ng/sample) 

 Total Chromium 2.1E+6 2.4E+3 4.2E+4 7.0E+3 5.9E+3 5.5E+3 

 Hexavalent Chromium 9.5E+5 2.5+E3 2.9E+4 5.6E+3 3.2E+3 4.2E+3 

Isokinetic Rate (%) 100.1 106.4 106.1 105.3 105.3 105.0 

EMISSIONS 

Concentration (ng/dscf) 

 Total Chromium 8600 8.7 170 26 24 21 

 Hexavalent Chromium 4000 9.1 120 20 13 16 

Emission Rate (mg/hr) 

 Total Chromium 1800 2.0 34 5.7 4.8 4.5 

 Hexavalent Chromium 820 2.1 24 4.6 2.6 3.5 

Mist Eliminator 

Control Efficiency (%)2

 Total Chromium 99.9 83.2 6.3 

 Hexavalent Chromium 99.7 80.8 --

3

Emission Factor (mg/amphr)4

 Total Chromium 1.78 2.0E-3 2.3E-2 3.9E-3 3.2E-3 3.0E-3 

 Hexavalent Chromium 0.81 2.1E-3 1.6E-2 3.1E-3 1.7E-3 2.3E-3 

DSCF means dry standard cubic feet. Standard conditions are 68 F and 29.92 inches Hg. 

DSCFM means dry standard cubic feet per minute. 

1 Hoist line operations were suspended for ~4 hours during Run 04. Emissions sampling runs were 

suspended for 2 of the 4 hours. 

2 Efficiency = [(Inlet, SI – Outlet, SO) / Inlet, SI] * 100

3 Efficiency could not be calculated 

4 Emissions Factors (mg/amp-hr) = Emission Rate (mg/hr) / Plating Tank Production Rate (amp-hrs/hr) 
Phase I – Test 1 & 2 Facility 1 

3
Phase I – Test 1 & 2 Facility 1 

4

Table VI-3 

Sigma Plating Company, Inc. Hoist Line Indoor Ambient Metals 

Sampling Dates – January 8 - 10 & 14 – 16, 2003 

Sampling Dates 1/8/2003* 1/9/2003 1/10/2003 1/14/2003 1/15/2003 1/16/2003 

Metals (ng/m3) 

Total Chromium 1,836 131 391 346 285 157 

Manganese 68 19 52 71 110 45 

Iron 10,430 2,153 4,164 7,099 15,127 3,134 

Nickel 3,090 271 695 1,010 1,243 430 

Cobalt 1.8 <1 1.6 2 1.9 1.2 

Copper 253 55 155 268 192 125 

Zinc 472 80 231 395 320 146 

Arsenic 1.1 <1 <1 2.2 1.9 <1 

Strontium 23 5.3 19 22 23 14 

Molybdenum 1.8 <1 2.1 3.9 25 3.2 

Tin 44 5.3 11 16 11 30 

Antimony 7.2 1.8 7.5 11 15 8 

Lead 811 42 122 126 67 47 

 

* January 8 was windy and dusty which may account for the higher 

concentrations. 
Phase I – Test 3 Facility 2 

5
Phase I – Test 3 Facility 2 

6
Phase I – Test 4 Facility 3 

7
Phase I – Test 4 Facility 3 

8

Table VI-II

 Van Nuys Plating Company, Inc.

 Indoor, Ambient Hexavalent Chromium Levels

Sample Number V-2A V-3A V-4A V-5A V-6A

Sample Date 4/9/2003 4/9/2003 4/10/2003 4/10/2003 4/11/2003

Sampling Time (minutes) 77 123 400 396 328

Volume Collected (Liters) 791.4 1264.1 4130.7 4128.6 3387.2

Cr (VI) collected (nanograms) 3.0 9.4 15.2 0.7 13.7

Concentration (ng/m^3) 3.8 7.4 3.7 0.7 4.1

 Daily averages 5.6 2.2 4.1
Phase II – Test 1 & 2 Facility 4 

9

Table VI-1 

Alta Plating Decorative Chromium Plating Tank 

Sampling Dates – January 27-29 & February 2-4, 2004 

Sampling Location 40 dynes/cm Surface Tension 30 dynes/cm Surface Tension 

Sample Number A-11 A-12 A-13 A-21 A-22 A-23 

Sampling Date 1/27/2004 1/28/2004 1/29/2004 2/2/2004 2/3/2004 2/4/2004 

 

Plating Tank Data 

Totalizer (amp-hours) 183 537 393 390 382 383 

Production Rate (amp-hrs/hr) 30.5 67.1 65.5 65.0 63.7 63.8 

Freeboard (inches to overflow)* 5.8 -.4.5 4.0 - 4.2 4.0 - 4.0 4.75 - 5.0 4.0 - 4.5 4.5 - 4.9 

Surface Tension (dynes/cm)* 39.3 – 39.9 40.7 – 39.3 40.1 – 39.7 30.8 – 28.9 30.5 – 28.9 29.2 – 28.4 

Chromic Acid Conc. (oz/gal) 37.7 34.3 35.9 35.1 34.5 34.6 

Bath Temperature (oF) 110 110 109 104 109 109 

 

Stack Data 

Stack Temperature ( 0F) 63 62 61 62 62 61 

Velocity (ft/sec) 23 21 21 21 20 21 

Static Pressure ("H20) -0.28 -0.25 -0.25 -0.27 -0.25 -0.26 

Stack Area (sq. ft.) 0.785 0.785 0.785 0.785 0.785 0.785 

Flow Rate (DSCFM) 1102 983 984 972 958 982 

Moisture (% of v/v) 1.0 1.0 0.9 1.0 1.2 1.0 

Sampling Data 

Sampling Time (minutes) 360 480 360 360 360 360 

Sample Volume (DSCF) 390.14 485.60 378.17 353.49 349.45 359.83 

Chromium Data (ng/sample) 

 Total Chromium 3110 4810 5220 1450 2860 1520 

 Hexavalent Chromium 2250 3330 3840 1113 2462 980 

Isokinetic Rate (%) 101 105 109 103 104 104 

EMISSIONS 

Concentration (ng/dscf) 

 Total Chromium 7.97 9.90 13.8 4.10 8.18 4.23 

 Hexavalent Chromium 5.77 6.86 10.2 3.15 7.05 2.72 

Emission Rate (mg/hr) 

 Total Chromium 0.53 0.58 0.82 0.24 0.47 0.25 

 Hexavalent Chromium 0.38 0.41 0.60 0.18 0.41 0.16 

Emissions Factors 

 (mg/amp-hr)**

 Total Chromium 0.017 0.009 0.012 0.004 0.007 0.004 

 Hexavalent Chromium 0.012 0.006 0.009 0.003 0.006 0.003 

DSCF & DSCFM means dry standard cubic feet and dry standard cubic feet per minute at 68 F and 29.92 

inches Hg. 

* Paired numbers show "start " - "end" of sample run results (i.e. Run A-11 started at 5.8 in. & 39.3 

dyne/cm). 
Phase II – Test 1 & 2 Facility 4 

10

** Emissions Factors (mg/amp-hr) = Emission Rate (mg/hr) / Plating Tank Production Rate (amp-hrs/hr) 

Sample Number: A-11-A A-12-A A-13-A

Sample Date: 1/27/2004 1/28/2004 1/29/2004

Sampling Time (minutes) 226 422 310

Volume Collected (liters) 2260 4220 3100

Cr (VI) collected (nanograms) 160 120 32

Indoor Ambient Concentration (ng/m3) 70 28 10

Sample Number: A-21-A A-22-A A-23-A

Sample Date: 2/2/2004 2/3/2004 2/4/2004

Sampling Time (minutes) 353 313 350

Volume Collected (liters) 3530 3130 3500

Cr (VI) collected (nanograms) 63 50 33

Indoor Ambient Concentration (ng/m3) 18 16 9.3

Table VI-2b

Alta Plating Company

Indoor Ambient Hexavalent Chromium 

30 dyne/cm Surface Tension

Table VI-2a

Alta Plating Company

Indoor Ambient Hexavalent Chromium 

40 dyne/cm Surface Tension
Phase II – Test 1 & 2 Facility 4 

11

Background Indoor Ambient Sampling Results: Facility 4 

Sample Number: A-33-A A-32-A A-31-A** A-30-A

Sample Date: 2/5/2004 2/6/2004 2/8/2004 2/9/2004

Sampling Time (minutes) 339 450 1747** 368

Volume Collected (liters) 3390 4500 17470 3680

Cr (VI) collected (nanograms) 270 190 69 210

Totalizer, amp-hours 130 182 ** 172

Indoor Ambient Concentration (ng/m3

) 79 41 3.9 57

* - These indoor ambient samples were collected after emissions sampling of the plating

tank was completed and the plating tank capture hood removed. 

** - Sample A-31-A was collected on a Sunday when Alta was not plating. However, the

sampler failed to shut off automatically. It was shut down manually at 8:00 am Monday -

after Alta began plating.

Ambient Results with Plating Tank Capture Hood Removed*

Table VI-2c

Alta Plating Company

Indoor Ambient Hexavalent Chromium 
Phase II – Test 3 Facility 5 

12

Table VI-1 

Sherm's Custom Plating Decorative Chromium Plating Tank Results Sampling 

Dates--March 9, 10, & 11, 2004 

Sampling Location Chromium 

Plating tank 

Chromium 

Plating tank 

Chromium 

Plating tank 

 Sample Date March 9, 2004 March 10, 2004 March 11, 2004 

 Sample Number S-1 S-2 S-3 

Plating Tank Data 

 Totalizer (amp-hours) 415 459 425 

 Production Rate (amp-hrs/hr) 69.2 76.5 81.7 

 Freeboard (inches to overflow)* 5.0-4.9 3.0-3.5 4.0-4.0 

 Chromic Acid Conc. (oz/gal) 34.2 32.6 Not Done 

 Temperature (oF) 109.5 109.8 109.8 

 Surface Tension (dynes/cm)* 35.6-35.9 37.5-35.9 37.8-37.9 

Stack Data 

 Stack Temp. (oF) 75 75 72 

 Velocity (ft/sec) 19.49 22.19 20.33 

 Static Pressure ("H2O) -0.23 -0.29 -0.19 

 Stack Area (sq. ft.) 0.785 0.785 0.785 

 Flow Rate (DSCFM) 904 1030 943 

 Moisture (% of v/v) 1.1 0.6 1.0 

Sampling Data 

 Sampling Time (minutes) 360 360 312 

 Sampling Volume (DSCF) 330.08 360.50 295.40 

 Chromium Data (ng/sample) 

 Total Chromium 19,440 22,600 22,730 

 Hexavalent Chromium 19,413 21,490 23,693 

 Isokinetic Ratio(%) 103.9 99.6 102.9 

 

EMISSIONS 

Concentration (ng/DSCF) 

 Total Chromium 58.89 62.69 76.95 

 Hexavalent Chromium 58.81 59.61 80.21 

Emission Rate (mg/hr) 

 Total Chromium 3.19 3.87 4.35 

 Hexavalent Chromium 3.19 3.68 4.54 

Emission Factors 

(mg/amp-hr)** 

 

 Total Chromium 0.046 0.051 0.053 

 Hexavalent Chromium 0.046 0.048 0.056 

DSCF means dry standard cubic feet at 68oF and 29.92" Hg. DSCFM means dry standard cubic 

feet per minute. 

*Paired values separated by a hyphen are "start-end" of day measurements. 

**Emission Factor = Emission rate/Production rate. 
Phase II – Test 3 Facility 5 

13

Table VI-2a 

Sherm's Custom Plating 

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results 

Ambient sampling during source testing with the hood in place 

Sample Number: S1-A S2-A S3-A 

Sample Date: 03/09/2004 03/10/2004 03/11/2004

Sampling Time (minutes) 300 335 300* 

Volume Collected (liters) 3000 3350 3000 

Cr (VI) Collected (nanograms) 200 130 190 

Indoor Ambient Concentration (ng/m3) 67 39 65 

* Note: Difference between the annotated start and stop time does not equal 300 

minutes. It is assumed the start time was written incorrectly since the sampling 

interval is read directly from the PQ-100. 

Background Indoor Ambient Sampling Results: Facility 5 

Table VI-2b 

Sherm's Custom Plating 

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results 

Ambient sampling after source testing with the hood removed 

Sample Number: S11-A S12-A S13-A 

Sample Date: 03/19/2004 03/20/2004 03/21/2004

Sampling Time (minutes) 393 417 340 

Volume Collected (liters) 3930 4170 3400 

Cr (VI) Collected (nanograms) 390 870 410 

Indoor Ambient Concentration (ng/m3) 100 210 120 
Phase II – Test 4 Facility 6 

14

Table VI-2 

Clovis Specialty Decorative Chromium Plating Tank Test Week 2 (Clovis2) 

Sampling Dates – October 19-21, 2004 

Sampling Location 

Sample Number C21 C22 C23 

Sampling Date 10/19/04 10/20/04 10/21/04 

 

Plating Tank Data 

Totalizer (amp-hours) 331 382 360 

Production Rate (amp-hrs/hr) 159 191 180 

Freeboard (inches to overflow)* 4.375 4.875 4.375 

Surface Tension (dynes/cm) 44.1 41.6 42.2 

Chromic Acid Conc. (oz/gal) 30.2 30.2 30.2 

Bath Temperature (oF) 106 110 112 

 

Stack Data 

Stack Temperature ( 0F) 68 67 63 

Velocity (ft/sec) 20.68 20.40 19.84 

Static Pressure ("H20) -0.22 -0.22 -0.24 

Stack Area (sq. ft.) 0.785 0.785 0.785 

Flow Rate (DSCFM) 945 931 922 

Moisture (% of v/v) 1.3 1.3 1.1 

Sampling Data 

Sampling Time (minutes) 125 120 120 

Sample Volume (DSCF) 118.65 111.03 111.23 

Chromium Data (ng/sample) 

 Total Chromium 20,990 12,960 18,670 

 Hexavalent Chromium 21,800 11,280 20,570 

Isokinetic Rate (%) 102.9 101.9 103.1 

EMISSIONS 

Concentration (ng/dscf) 

 Total Chromium 177 117 168 

 Hexavalent Chromium 184 102 185 

Emission Rate (mg/hr) 

 Total Chromium 10.0 6.5 9.3 

 Hexavalent Chromium 10.4 5.7 10.2 

Emissions Factors 

 (mg/amp-hr)**

 Total Chromium 0.063 0.034 0.052 

 Hexavalent Chromium 0.065 0.030 0.057 

DSCF & DSCFM means dry standard cubic feet and dry standard cubic feet per minute at 68 F and 29.92 inches 

Hg. 

* Measured at the start of the plating day. 

** Emissions Factors (mg/amp-hr) = Emission Rate (mg/hr) / Plating Tank Production Rate (amp-hrs/hr) 
Phase II – Test 4 Facility 6 

15

Background Indoor Ambient Sampling Results: Facility 6 

Sample Number: C4-A C5-A C6-A C7-A

Sample Date: 6/1/2004 6/2/2004 6/3/2004 6/4/2004

Sampling Time (minutes) 1,403 1,317 1,115 470

Volume Collected (liters) 14,030 13,068 11,150 4,653

Plating Tank Amp-hours 1 72 22 51

Cr (VI) collected (nanograms) 1700 3600 1500 2100

Indoor Ambient Concentration (ng/m3) 120 280 130 460

(without Capture Hood) 

Table A1-1b

Clovis Specialty

Indoor Ambient Hexavalent Chromium 
Phase II – Test 4 Facility 6 

16

Table A2-1a 

Clovis Specialty Plating – Test Week 2 

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results 

(Ambient sampling on rectifier during source testing with capture hood in place.) 

Sample Number: C20-RA C21-RA C22-RA C23-RA 

Sample Date: 10/18/04 10/19/04 10/20/04 10/21/04 

Sampling Time (minutes) 196 308 143 132 

Volume Sampled (liters) 1960 3080 1430 1320 

Cr (VI) Collected (ng/sample) 300 5000 470 1800 

Indoor Ambient Concentration 

(ng/m3) 150 1600 330 1300 

This rectifier is next to the plating tank, but outside the source test capture hood. 

Table A2-1b 

Clovis Specialty Plating – Test Week 2 

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results 

(2nd parallel ambient sampling during source testing with capture hood in place.) 

Sample Number: C20-CA C21-CA C22-CA C23-CA 

Sample Date: 10/18/04 10/19/04 10/20/04 10/21/04 

Sampling Time (minutes) 188 308 139 ** 

Volume Sampled (liters) 1880 3050 1380 ** 

Cr (VI) Collected (ng/sample) 270 1700 700 810 

Indoor Ambient Concentration 

(ng/m3) 150 560 510 ** 

CA samples parallel RA samples above - away from the tank and rectifier, but in the 

same room. RA samples were collected at the same location as Week 1 indoor samples. 

** Air Volume data not recorded. Indoor concentration can not be calculated.
Phase II – Test 5 Facility 6 

17

Table VI-3 

Clovis Specialty Decorative Chromium Plating Tank Test Week 3 (Clovis 3) 

Sampling Dates – May 24-25, 2005 

Sampling Location 

Sample Number C31 C32 C33 

Sampling Date 5/24/05 5/25/05 AM 5/25/05 PM 

 

Plating Tank Data 

Totalizer (amp-hours) 385 309 316 

Production Rate (amp-hrs/hr) 192.5 154.5 158 

Freeboard (inches to overflow)* 5 5/8 5 5/8 5 5/8 

Surface Tension (dynes/cm) 36.6 32.7 22.1 (fume suppressant 

added before sampling) 

Chromic Acid Conc. (oz/gal) 25.0 25.0 25.0 

Bath Temperature (oF) 108 110 110 

 

Stack Data 

Stack Temperature ( 0F) 91 86 92 

Velocity (ft/sec) 19.8 18.6 18.9 

Static Pressure ("H20) -0.20 -0.21 -0.20 

Stack Area (sq. ft.) 0.785 0.785 0.785 

Flow Rate (DSCFM) 871 828 836 

Moisture (% of v/v) 1.2 1.0 0.7 

Sampling Data 

Sampling Time (minutes) 120 120 120 

Sample Volume (DSCF) 103 96.9 97.8 

Chromium Data (ng/sample) 

 Total Chromium 19,800 14,284 18,390 

 Hexavalent Chromium 19,690 13,284 18,100 

Isokinetic Rate (%) 101.2 100.0 99.8 

EMISSIONS 

Concentration (ng/dscf) 

 Total Chromium 192 147 188 

 Hexavalent Chromium 191 137 185 

Emission Rate (mg/hr) 

 Total Chromium 10 7.3 9.4 

 Hexavalent Chromium 10 6.8 9.3 

Emissions Factors 

 (mg/amp-hr)**

 Total Chromium 0.052 0.047 0.059 

 Hexavalent Chromium 0.052 0.044 0.059 

DSCF & DSCFM means dry standard cubic feet and dry standard cubic feet per minute at 68 F and 29.92 inches 

Hg. 

* Measured at the start of the plating day. 

** Emissions Factors (mg/amp-hr) = Emission Rate (mg/hr) / Plating Tank Production Rate (amp-hrs/hr) 
Phase II – Test 5 Facility 6 

18

Table A3-1a 

Clovis Specialty Plating – Test Week 3 

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results 

(Ambient indoor sampling on rectifier during source testing with capture hood in place.) 

Sample Number: C30-RA C31-RA C32-RA C33-RA 

Sample Date: 5/24/05 5/24/05 5/25/05 5/25/05 

Sampling Time (minutes) 264 122 128 125 

Volume Sampled (liters) 2640 1220 1280 1250 

Cr (VI) Collected (ng/sample) 5837 1964 646 1069 

Indoor Ambient Concentration 

(ng/m3) 

2,200 1,600 510 860 

This rectifier is next to the plating tank, but outside the source test capture hood. 

Table A3-1b 

Clovis Specialty Plating – Test Week 3 

Indoor (PQ-100) Ambient Hexavalent Chromium Sampling Results 

(Ambient indoor sampling during source testing with capture hood in place.) 

Sample Number: C31-CA C32-CA C33-CA 

Sample Date: 5/24/05 5/25/05 5/25/05 

Sampling Time (minutes) 132 129 121 

Volume Sampled (liters) 1320 1290 1210 

Cr (VI) Collected (ng/sample) 1425 978 1067 

Indoor Ambient Concentration 

(ng/m3) 

 1,100 760 880 

CA samples parallel RA samples above - away from the tank and rectifier, but in the 

same room. RA samples were collected at the same location as Clovis 1 indoor samples.
Phase II – Test 6 Facility 6 

19

Table VI-4 

Clovis Specialty Decorative Chromium Plating Tank Test Week 4 (Clovis 4) 

Sampling Dates – June 29-30, 2005 

Sampling Location 

Sample Number C41 C42 C43 

Sampling Date 6/29/05 6/30/05 6/30/05 

 

Plating Tank Data 

Totalizer (amp-hours) 356 299 345 

Production Rate (amp-hrs/hr) 178 149.5 172,5 

Freeboard (inches to overflow)* 4.5 4.0 4.0 

Surface Tension (dynes/cm) 31.5 31.5 31.5 

Chromic Acid Conc. (oz/gal) 28.2 28.2 28.2 

Bath Temperature (oF) 105.6 108.6 107.6 

 

Stack Data 

Stack Temperature ( 0F) 87.5 87.5 95 

Velocity (ft/sec) 21.6 19.0 19.8 

Static Pressure ("H20) -0.24 -0.17 -0.20 

Stack Area (sq. ft.) 0.785 0.785 0.785 

Flow Rate (DSCFM) 955 837 864 

Moisture (% of v/v) 1.3 1.6 1.3 

Sampling Data 

Sampling Time (minutes) 120 120 120 

Sample Volume (DSCF) 111 100 102 

Chromium Data (ng/sample) 

 Total Chromium 40,860 14,900 29,290 

 Hexavalent Chromium 29,910 9,890 25,020 

Isokinetic Rate (%) 99.3 102 101 

EMISSIONS 

Concentration (ng/dscf) 

 Total Chromium 368 149 287 

 Hexavalent Chromium 269 99 245 

Emission Rate (mg/hr) 

 Total Chromium 21 7.5 15 

 Hexavalent Chromium 15 5.0 13 

Emissions Factors 

 (mg/amp-hr)**

 Total Chromium 0.12 0.050 0.086 

 Hexavalent Chromium 0.087 0.033 0.074 

DSCF & DSCFM means dry standard cubic feet and dry standard cubic feet per minute at 68 F and 29.92 

inches Hg. 

* Measured at the start of the plating day. 

** Emissions Factors (mg/amp-hr) = Emission Rate (mg/hr) / Plating Tank Production Rate (amp-hrs/hr) 
Phase II – Test 6 Facility 6 

20

Sample Collection: JUNE 2005 

Air Volume Cr(VI) Cr(VI) Plating Tank 

Filter ID liters ng/ml ng recovered ng/liter ng/m3Total amp-hrs

C41-RA 1,330 98.68 1480 1.113 1113 356

C41-CA 1,320 206.81 3102 2.350 2350 "

C41-CAC 136 21.67 325 2.390 2390 "

C42-RA 1,570 46.91 704 0.448 448 299

C42-CA 1,540 122.14 1832 1.190 1190 "

42-CAC 171 "

C43-RA 1,200 63.13 947 0.789 789 345

C43-CA 1,190 101.59 1524 1.281 1281 "

C43-CAC 131 12.91 194 1.481 1481 "

extraction volume = ~15 ml.

 -CAC sampler was located ~1 meter from CA sampler but sampled at 1 lpm instead of 10 lpm.

 -CA sampler was located behind and on the opposite side of the sampling hood.

 -RA sampler was located on the plating tank rectifier and next to the sampling hood.

(with Capture Hood over Plating Tank)

Table A4-1

Indoor Ambient Hexavalent Chromium Results

Clovis Specialty Plating (Clovis 4) Test

Cr(VI)
Phase II – Test 7 Facility 7 

21

Table VI 

Walker’s Custom Chrome Chromium Plating Tank 

Sampling Dates – February 15-23, 2006 

Sampling Location 

Sample Number W-11 W-12 W-13 

Sampling Date 2/15/06 2/16/06 2/17/06 

Plating Tank Data 

Totalizer (amp-hours) 331 300 300 

Production Rate (amp-hrs/hr) 165.5 75 75 

Freeboard (inches to overflow) 4.75 4.5 5 

Surface Tension (dynes/cm) 35.1 35.4 35.4 

Chromic Acid Conc. (oz/gal) 34.8 34.8 34.8 

Bath Temperature (oF) 90-100 92-105 98-107 

 

Stack Data 

Stack Temperature ( 0F) 65 61 61 

Velocity (ft/sec) 19.2 20.2 21.6 

Static Pressure ("H20) -0.26 -0.24 -0.25 

Stack Area (sq. ft.) 0.785 0.785 0.785 

Flow Rate (DSCFM) 899 958 1000 

Moisture (% of v/v) 0.7 0.5 0.9 

Sampling Data 

Sampling Time (minutes) 120 240 240 

Sample Volume (DSCF) 110.56 233.10 235.72 

Chromium Data (ng/sample) 

 Total Chromium 1700 5090 4680 

 Hexavalent Chromium 1262 3232 3610 

Isokinetic Rate (%) 105 104 101 

EMISSIONS 

Concentration (ng/dscm) 

 Total Chromium 543 771 701 

 Hexavalent Chromium 403 490 541 

Emission Rate (mg/hr) 

 Total Chromium 0.83 1.25 1.19 

 Hexavalent Chromium 0.62 0.80 0.92 

Emissions Factors 

 (mg/amp-hr)

 Total Chromium 0.0050 0.017 0.016 

 Hexavalent Chromium 0.0037 0.011 0.012 

Standard Conditions = 68o F and 29.92 in. Hg. DSCF = dry standard cubic feet. DSCM = dry 

standard cubic meter. DSCFM = dry standard cubic feet per minute. 
Appendix G: Hexavalent Chromium Content Contained in Dust Samples Collected from Chromium Plating Shops in San 

Date Location % of Total Hex Cr Total 

Sampled that is Hex mg/kg

8/20/2002

within 2 feet from the side of the chrome plating tank near the emission collection vent ducts

16% 4,990 30,4

8/20/2002 the corners of the back doors (entry and roll up garage doors) 2% 3.6 225/23/2002 on top of tank, within 1 foot in front of tank. 37% 33,000 88,35/23/2002 near back north east door. N/A < 0.8 1,925/23/2002 near back north west door. N/A < 0.8 4,925/23/2002 in adjacent alley north of the facility. N/A < 0.8 237/25/2002

within 5 feet in front of tank near rectifier. Note: sample taken underneath the wooden operating flooring

31% 30,800 98,8

7/26/2002 on tank, within 3 feet in front of tank. 67% 89,800 135,07/26/2002 near roll up garage door in back of facility. N/A < 0.8 776/28/2002 within 2 feet in front of tank, on top of 5 foot high DI? cylinder. 25% 39,200 156,0
Appendix G: Hexavalent Chromium Content Contained in Dust Samples Collected from Chromium Plating Shops in San 

6/28/2002

within 2 feet behind tank. Note: no "outlet" sample was taken since smoke indicated changing air currents. 

34% 23,900 69,9

6/18/2002

on lip of tank, within 1 foot in front of tank, within 2 feet in front of tank (near activator tank).

52% 30,000 58,0

6/18/2002 near back door of facility. N/A < 20 6,836/25/2002

within 3 feet to the right side of tank P7-4 (on cement floor inside paneling), within 3 feet in front right side of Tank P7-8.

11% 407 3,79

6/25/2002 near (east?) door next to composite mesh pad. 7% 172 2,416/25/2002

on surface within 2 feet of tank P7-13. Note: surface is two feet higher tank top of tank P7-13.

0.1% 81 69,8

7/9/2002

within 6 feet in front of tank (near rinse tank), within 2 feet in the side of tank, within 10 feet behind tank. Note: sample taken on lower cement flooring which is lower than the wooden operating flooring.

30% 9,560 31,4
Appendix G: Hexavalent Chromium Content Contained in Dust Samples Collected from Chromium Plating Shops in San 

7/9/2002 near roll up garage door on side of facility. N/A < 0.8 19

7/17/2002

within 1 foot to the left of the tank on cement floor of secondary containment. Note: no elevated wooden operating floor at facility.

22% 8,160 37,5

7/10/2002

within 1 foot in front of tank, within 5 feet in front of tank, within 1 foot behind tank.

13% 1,320 10,1

7/10/2002

near front windows of facility, along south east wall of polishing room.

N/A < 0.8 18

7/16/2002 on tank, within 2 feet in front of tank. 31% 28,700 93,3

7/16/2002 near front door of facility. N/A < 0.8 34
Appendix H 

Air Quality Modeling Parameters and Results 
Appendix H 

Appendix H 1

Air Quality Modeling of Emissions from Shops with 

Chromium Plating Services 

Prepared by: Tony Servin, P.E., 

Planning and Technical Support Division, 

California Air Resources Board, 

California Environmental Protection Agency 

Date: November 14, 2004 

Summary 

It has been requested to evaluate the air quality impacts of emissions from shops 

with chromium plating services. The shops in this analysis vent emissions through 

forced ventilation (stacks) or natural ventilation (fugitive). The facilities with forced 

ventilation are grouped into four categories directly related to expected plume rise 

and amp-hour usage (low, medium, high, or horizontal). The facilities with natural 

ventilation are grouped into three categories dependent on the physical size of the 

shop (small, medium, or large). The dispersion of emissions is simulated with the 

latest version of the U.S. EPA air dispersion model ISCST3 (02035). The 

meteorological data used in the dispersion are collected from four locations 

throughout the state (Oakland, Fresno, San Diego, and Pasadena). In addition, a 

worst-case analysis is also simulated with screening meteorological conditions. 

The analysis is based on a unit emission rate (1 g/s). Therefore, to obtain the 

estimated annual average concentration of hexavalent chromium in the air, the 

model results should be multiplied by the pollutant emission rate. Table S-1 shows 

a summary of the maximum chi/q1

 for the different shop types and screening 

meteorological conditions. The maximum chi/q is 1500 (μg/m3)/(g/s) for shops with 

horizontal stacks or small shops with fugitive ventilation. Details of the analysis, 

example calculations, and additional results with historical meteorological data are 

described below. 

 

1

 Chi/q is the predicted concentration based on an emission rate of 1 g/s. The chi/q is multiplied by 

the actual emission rate (g/s) to obtain the downwind concentration (μg/m3). This is possible 

because the downwind concentration is directly proportional to the emission rate as described in the 

ISCST3 air quality model. 
Appendix H 

Appendix H 2

Table S.1 – Maximum (Screening) 

Annual Average Chi/Q (μg/m3)/(g/s) 

from Shops with Chromium Plating

Shop Distance Downwind 

Type Size 20 m 30 m 40 m 50 m 100 m 200 m 500 m 1000 m

Low 310 340 300 190 64 12 4 

Medium 140 140 130 84 47 12 4 

High 72 89 88 69 43 11 3 

Stack 

Horizontal 1500 1300 1000 780 250 70 12 4 

Small 1500 990 710 530 210 61 12 3 

Fugitive Medium 1000 700 520 430 190 59 12 3 

Large 620 470 370 300 160 54 11 3 

• Multiply by hourly emissions [annual inventory (g) / (3285 hrs/yr) / (3600 s/hr)] to 

obtain annual average concentration. 

• A blank cell indicates no calculation because the plume is in the building wake or is 

still aloft. 

Approach 

Facilities (shops) that provide decorative and hard chromium plating services have 

the potential to emit hexavalent chromium. It has been requested by ARB’s 

Stationary Source Division to analyze the downwind dispersion of emissions from 

various shop configurations for chrome plating facilities. Data for 26 different shops 

with forced ventilation (stacks) and shops with natural ventilation (fugitive) in three 

sizes are provided by ARB’s Stationary Source Division (Appendix H-1). The data 

for the shops with stacks are summarized into four categories based on the 

potential for plume rise and amp-hour consumption (further details below). 

The stack parameters and fugitive building parameters are input to the latest 

version of the U.S. EPA ISCST3 (Version 02035) air quality model to estimate 

downwind impacts. Urban dispersion coefficients are used in ISCST3. Receptor 

heights are set at 1.2 meters above ground level. Terrain is assumed to be flat. 

The meteorological data used in the dispersion are collected from four locations 

throughout the state (Oakland, Fresno, San Diego, and Pasadena). In addition, a 

worst-case analysis is also simulated with screening meteorological conditions. 

The model results are presented as annual average chi/q, which are concentrations 

based on a unit emission rate (1 g/s). In this way, the model results may be scaled 

to represent annual average concentrations from any facility by multiplying the chi/q 

with the facility emission rate. 

Release Parameters - Stack Emissions 

Stack data for shops with forced ventilation provided by SSD (Appendix H-1). 

These stack data are grouped in order to reduce the number of air dispersion model 
Appendix H 

Appendix H 3

runs. Since all stacks essentially emit at approximately ambient conditions, 

temperature is not considered for stratifying the data. Of the stack parameters with 

vertical stack releases, we calculate the stack height (feet) multiplied by the gas 

flow (cubic feet per second). These two parameters are directly used to estimate 

final plume rise in the air dispersion model and are related to estimating downwind 

concentration. Figure 1 shows the stratified data as a function of facility amp-hours. 

Figure 1 – Height * Stack Flow vs Amp - Hours 

The data shown in Figure 1 are stratified into four groups. Table 1 shows the four 

stratified groups. 

Table 1 – Stack Data Stratified 

Shop 

Group 

Plume Rise 

Potential Amp Hours 

A Low < 5,000,000 amp-hrs 

B Medium 5,000,000 – 50,000,000 amp-hrs 

C High > 50,000,000 amp-hrs 

D Horizontal any amp-hrs with horizontal stack or raincap 

Group D is for all stacks with horizontal releases or raincaps regardless of amphours. Plume rise is canceled when the stacks are horizontal or in the presence of 

a raincap for ambient temperature plumes. 

 

-

2,000

4,000

6,000

8,000

10,000

12,000

14,000

0 10,000,000 20,000,000 30,000,000 40,000,000 50,000,000 60,000,000 70,000,000 80,000,000 90,000,000

Amp-Hrs

FT-CFS

Group B (5e6 - 50e6 amp-hrs)

Group A (<5e6 amp-hrs)

Group C (>50e6 amp-hrs)
Appendix H 

Appendix H 4

Mean stack conditions for the vertical stacks, groups A-C, are used for each group 

in Table 1 as inputs to the air dispersion model. Figure 1 also shows data that lie 

outside of the groups. These data are not used in the mean. As a result, the 

predicted downwind concentrations for groups A and B will be biased towards 

overestimation of the mean. Table 2 shows the mean stack parameters for the four 

groupings. The stack data for the 26 shops (Appendix H-1) are incomplete for all 

necessary parameters to estimate plume rise. Therefore the mean conditions 

calculated in Table 2 is based on data from the shops where all parameters are 

available. 

Table 2 – Stack Parameters 

Parameter Group A Group B Group C Group D 

Number of Facilities 4 3 3 4 

Flow (cfs) 28 111 200 na 

Diameter (m) 0.32 0.66 0.92 0.81 

Velocity (m/s) 10.4 12.2 8.5 0.001 

Temperature (C) 24 24 24 24 

Stack Height (m) 9.1 9.1 12.8 5.6 

Building Height (m) 8.8 8.8 12.5 5.3 

Building Length (m) 10 10 10 10 

Note 1: Building length, width and height are used for building 

downwash. We assume all stacks are impacted by building 

downwash. Therefore, building height is one foot (0.3 m) below 

stack height and building length and width is assumed to be ten 

meters. 

Note 2: Raincaps and horizontal stacks (group D) are treated differently 

by setting the exit velocity to 0.001 m/s, turning stacktip 

downwash off, and reducing the stack height by three times the 

stack diameter (OEHHA Air Toxics Hot Spots Program Risk 

Assessment Guidelines, Part IV, 2000). 

Release Parameters - Fugitive Emissions 

Data for the shops with natural ventilation are provided by SSD (Appendix H-1). 

Table 3 shows a summary of the assumed release parameters for volume source 

releases in the dispersion model. The release parameters summarized in Table 3 

reflect the lower range of the building dimensions in order to bias the predicted 

concentrations towards overestimation. 

Table 3 – Volume (Fugitive) Source Parameters 

Parameter Group A-Vol 

(Small) 

Group B-Vol 

(Medium) 

Group C-Vol 

(Large) 

Number of Facilities 14 42 11 

Area Size (m2) <279 279 – 929 929 – 2787 

Modeled Length (m) 10 17 30 

Release Height (m), H/2 2.5 2.5 2.5 

Syo (m), L/4.3 2.3 4.0 7.0 

Szo(m), H/2.15 2.3 2.3 2.3 

20 m receptor distance (m) 25 28 35 
Appendix H 

Appendix H 5

Meteorological Data 

Meteorological data for this analysis are from four representative locations plus a 

screening analysis. Table 4 shows the latest consecutive five years of processed 

meteorological data, as recommended by the U.S. EPA Guideline on Air Quality 

Models. Shorter periods are used where longer periods are not available. The 

operating period for the chrome platers is 6 am to 3 pm. Therefore, Table 4 also 

includes a summary of meteorological conditions during normal operating hours. 

Appendix H-2 is the wind rose companion for Table 4. 

Table 4 – Meteorological Data Summary 

Oakland Fresno San Diego 

(Miramar) Pasadena screening 

Period Winds 1960-1964 1985-1989 1967-1971 1981 

Avg. 

Speed 24 4.5 m/s 3.1 m/s 2.8 m/s 1.6 m/s 

hours Calms 11% 14% 17% 22% 

Avg. 

Speed 6 am – 4.5 m/s 2.9 m/s 3.1 m/s 1.6 m/s 

3 pm Calms 9% 13% 14% 16% 

Screening 

meteorological data 

are restricted to 

P-G stabilities A-D 

(daytime conditions 

only). 

Screening meteorological data represents inputs used in the U.S. EPA SCREEN3 

air dispersion model. Our application is limited to daytime hours, Pasquill-Gifford 

stabilities A through D, since it is assumed emissions occur within the time period of 

6 am to 3 pm. To estimate annual averages from the screening 1-hour averages, 

we multiply by the scaling factors of 0.5 to obtain an eight hour average and then 

we multiply by 9/24 to obtain the annual average as described in the HARP User 

Guide, December 2003. 

Receptors 

Receptors are placed at a minimum distance of 20 meters from the edge of building 

or stack. Polar receptors are used to plot the maximum downwind annual average 

concentration regardless of wind direction. Flagpole receptors set at 1.2 meters 

(4 ft.) above ground. 
Appendix H 

Appendix H 6

Results 

Table 5 shows the annual average chi/q for screening conditions. As a result the 

chi/q in Table 5 are biased towards overprediction. Additional tables are provided 

below that show results with actual meteorological conditions for four locations in 

the state. The average emission rate (grams/second) should be multiplied by the 

chi/q to obtain the annual average concentration (μg/m3). The average emission 

rate (grams/second) is based on nine hour days and 365 days per year. This is 

lower than the actual hourly emission rate during plating activity. However, since 

emissions may be distributed at any time throughout 6 am to 3 pm, we assumed the 

emissions are uniformly distributed over nine hours for modeling purposes. 

Table 5 – Maximum (Screening) 

Annual Average Chi/Q (μg/m3

)/(g/s) 

from Shops with Chromium Plating

Shop Distance Downwind 

Type Size 20 m 30 m 40 m 50 m 100 m 200 m 500 m 1000 m

Low 310 340 300 190 64 12 4 

Medium 140 140 130 84 47 12 4 

High 72 89 88 69 43 11 3 

Stack 

Horizontal 1500 1300 1000 780 250 70 12 4 

Small 1500 990 710 530 210 61 12 3 

Fugitive Medium 1000 700 520 430 190 59 12 3 

Large 620 470 370 300 160 54 11 3 

• Multiply by hourly emissions [annual inventory (g) / (3285 hrs/yr) / (3600 s/hr)] to 

obtain annual average concentration. 

• A blank cell indicates no calculation because the plume is in the building wake or is 

still aloft. 

As an example for using Table 5, if the annual hexavalent chromium inventory for a 

shop is 0.1 lbs/yr, the maximum annual average concentration is estimated as 

follows: 

The chi/q results based on meteorological data from Oakland, Fresno, San Diego, 

and Pasadena are shown in Tables 6 through 9, respectively. The example 

calculation shown above should be used to convert the chi/q in Tables 6-9 to 

annual average concentrations. The results based on Pasadena meteorology, 

Table 9, show the highest chi/q. 

)/(3600)/(3285

)/(454

)/(1.0

)/(

)/(

0058.0 1500

3

3

rhrs hrsy

lbg

yrlbs

sg

mug

m

g

AnnualAverage

×

= = × ×

μ

chi/q inventory conversion factors
Appendix H 

Appendix H 7

Table 6 – Maximum (Oakland) 

Annual Average Chi/Q (μg/m3

)/(g/s) 

from Shops with Chromium Plating

Shop Distance Downwind 

Type Size 20 m 30 m 40 m 50 m 100 m 200 m 500 m 1000 m

Low 58 51 43 17 4.9 0.8 0.2 

Medium 46 44 39 16 4.8 0.8 0.2 

High 17 22 22 13 4.4 0.8 0.2 

Stack 

Horizontal 170 120 86 63 19 5.0 0.8 0.2 

Small 180 110 70 50 17 4.7 0.8 0.2 

Fugitive Medium 140 83 58 45 17 4.7 0.8 0.2 

Large 97 66 48 36 17 4.7 0.8 0.2 

• Multiply by hourly emissions [annual inventory (g) / (3285 hrs/yr) / (3600 s/hr)] to 

obtain annual average concentration. 

• A blank cell indicates no calculation because the plume is in the building wake or is 

still aloft. 

Table 7 – Maximum (Fresno) 

Annual Average Chi/Q (μg/m3)/(g/s) 

from Shops with Chromium Plating

Shop Distance Downwind 

Type Size 20 m 30 m 40 m 50 m 100 m 200 m 500 m 1000 m

Low 61 54 44 16 4.7 0.8 0.2 

Medium 43 41 36 15 4.4 0.8 0.2 

High 17 23 23 13 4.1 0.7 0.2 

Stack 

Horizontal 180 130 87 63 19 4.9 0.8 0.2 

Small 180 110 70 50 17 4.7 0.8 0.2 

Fugitive Medium 140 83 58 45 17 4.7 0.8 0.2 

Large 95 65 47 36 17 4.6 0.8 0.2 

• Multiply by hourly emissions [annual inventory (g) / (3285 hrs/yr) / (3600 s/hr)] to 

obtain annual average concentration. 

• A blank cell indicates no calculation because the plume is in the building wake or is 

still aloft. 
Appendix H 

Appendix H 8

Table 8 – Maximum (San Diego, Inland) 

Annual Average Chi/Q (μg/m3)/(g/s) 

from Shops with Chromium Plating

Shop Distance Downwind 

Type Size 20 m 30 m 40 m 50 m 100 m 200 m 500 m 1000 m

Low 71 64 53 20 5.4 0.9 0.2 

Medium 49 47 41 17 5.2 0.9 0.2 

High 20 27 27 15 4.8 0.8 0.2 

Stack 

Horizontal 220 150 110 75 22 5.6 0.9 0.2 

Small 220 130 85 60 20 5.3 0.9 0.2 

Fugitive Medium 220 100 71 54 20 5.3 0.9 0.2 

Large 120 83 59 44 20 5.3 0.9 0.2 

• Multiply by hourly emissions [annual inventory (g) / (3285 hrs/yr) / (3600 s/hr)] to 

obtain annual average concentration. 

• A blank cell indicates no calculation because the plume is in the building wake or is 

still aloft. 

Table 9 – Maximum (Pasadena) 

Annual Average Chi/Q (μg/m3

)/(g/s) 

from Shops with Chromium Plating

Shop Distance Downwind 

Type Size 20 m 30 m 40 m 50 m 100 m 200 m 500 m 1000 m

Low 130 120 100 38 11 1.7 0.4 

Medium 52 53 50 28 9.6 1.7 0.4 

High 25 38 39 25 9.0 1.6 0.4 

Stack 

Horizontal 470 320 220 150 43 11 1.8 0.4 

Small 420 250 160 120 39 10 1.7 0.4 

Fugitive Medium 340 190 130 100 38 10 1.7 0.4 

Large 230 150 110 81 38 10 1.7 0.4 

• Multiply by hourly emissions [annual inventory (g) / (3285 hrs/yr) / (3600 s/hr)] to 

obtain annual average concentration. 

• A blank cell indicates no calculation because the plume is in the building wake or is 

still aloft. 
Appendix H-1 

Appendix H 9

Appendix H-1 

Chromium Plating Shop Physical Descriptions for 

Emission Release Parameters 

Provided by ARB’s Stationary Source Division 
Appendix H-1 

Appendix H 10

Chromium Plating & Anodizing Facilities Dispersion Modeling Parameters 

There are two types of facilities that need to be modeled. Facilities with ventilation 

systems (49%), and facilities without ventilation systems (51%). 

Ventilated facilities with stacks:

Amp-hr distribution: Range Median Mean 

500 – 83,000,000 1,000,000 8,000,000 

 

Operating Parameter vary from continuous operation to the minimum of 4 hrs/day, 5 

days/week 

Facility 

Amp-hrs 

Stack height 

(ft) 

Stack 

diameter (in) 

Exit Velocity 

(ft/sec) 

Temperature 

(

o

F) 

10,000 building height 10 X 15 26.56 78.5 

35,000 25 11.5 X 14.5 18.1 82 

200,000 25-Hor 34 21.5 78 

225,000 26 13.5 43.2 73 

1,100,000 building height 15 X 7.5 28.9 70 

1,300,000 building height 19 1/2 X 26 13 85 

1,400,000 30 28 58.7 69 

2,200,000 ? 12 50.4 75 

2,200,000 32 8 47.3 70 

4,300,000 34 14 28 69 

5,100,000 55 26 58.6 77 

8,700,000 25 30.75 31.2 75 

9,800,000 30 13.5 67 94 

10,700,000 48 35 55 

12,000,000 45 32 32.6 91 

17,800,000 building+185'' 32 56.8 81 

18,500,000 25-Hor 26 X 22 17.5 70 

24,000,000 30 30 21.3 78 

28,700,000 30-horizontal 27.75 X 39.75 23.75 78 

30,500,000 25-Hor 26.75 X 21.75 21 60 

34,000,000 Building +11' 24 16 84 

62,000,000 40.5 34 32.9 75 

39 39 40.83 78 

73,500,000 50 39 18.5 64 

50 39 13.5 64 

79,000,000 36 36 33.7 70 

South Coast Data: on stack height (64): 

28 with 4.3 – 7.3m stack 30 with 7.3 – 15 m stack 5 with > 15m stack 
Appendix H-1 

Appendix H 11

Unventilated Facilities:

Volume source we need building dimensions. The source has usually one tank. 

Amp-hr distribution: Range Median Mean 

120 – 10,000,000 70,000 470,000 

 

Operating Parameter vary from 12 hrs/day, 7days/week to the minimum of 2 

hrs/day, 5 days/week 

SCAQMD building dimensions for 68 volume sources 

14 with < 279 m2

42 with 279 – 929 m2

11 with 929 – 2,787 m2
Appendix H-2 

Appendix H 12

Appendix H-2 

Wind Roses and Modeling Outputs 
Appendix H-2 

Appendix H 13

Figure B1 – Oakland Wind Rose (6 am – 3 pm) 

Figure B2 – Oakland Wind Rose (All Hours) 

DATE:

10/22/2004

W RPLOT View - Lakes Environmental Software

WIND ROSE PLOT:

Station # 23230, Oakland Airport

COMMENTS:

All hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

NORTH

SOUTH

WEST EAST

4%

8%

12%

16%

20% DATA PERIOD:

1960-1964 

Jan 1 - Dec 31

00:00 - 23:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 10.63%

AVG. WIND SPEED:

4.51 m/s

CALM WINDS:

10.63%

TOTAL COUNT:

43848 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)

DATE:

10/22/2004

WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT:

Station # 23230, Oakland Airport

COMMENTS:

All hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

NORTH

SOUTH

WEST EAST

4%

8%

12%

16%

20% DATA PERIOD:

1960-1964 

Jan 1 - Dec 31

06:00 - 14:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 8.79%

AVG. WIND SPEED:

4.47 m/s

CALM WINDS:

8.79%

TOTAL COUNT:

16443 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)
Appendix H-2 

Appendix H 14

Figure B3 – Fresno Wind Rose (6am – 3pm) 

Figure B4 – Fresno Wind Rose (All Hours) 

DATE:

10/22/2004

WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT:

Station # 93193, Fresno Air Terminalt

COMMENTS:

6 am to 3 pm hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

California Air Resources 

Board

NORTH

SOUTH

WEST EAST

5%

10%

15%

20%

25% DATA PERIOD:

1985-1989 

Jan 1 - Dec 31

00:00 - 23:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 14.31%

AVG. WIND SPEED:

3.08 m/s

CALM WINDS:

14.31%

TOTAL COUNT:

43824 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)

DATE:

10/22/2004

WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT:

Station # 93193, Fresno Air Terminalt

COMMENTS:

All hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

NORTH

SOUTH

WEST EAST

3%

6%

9%

12%

15% DATA PERIOD:

1985-1989 

Jan 1 - Dec 31

06:00 - 14:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 13.34%

AVG. WIND SPEED:

2.87 m/s

CALM WINDS:

13.34%

TOTAL COUNT:

16434 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)
Appendix H-2 

Appendix H 15

Figure B5 – San Diego (Miramar) Wind Rose (6am – 3pm) 

Figure B6 – San Diego (Miramar) Wind Rose (All Hours) 

DATE:

10/22/2004

WRPLOT View - Lakes Environmental Software

WIND ROSE PLOT:

Station # 93107, San Diego (Miramar)

COMMENTS:

6am - 3pm hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

California Air Resources 

Board

NORTH

SOUTH

WEST EAST

3%

6%

9%

12%

15% DATA PERIOD:

1967-1971 

Jan 1 - Dec 31

00:00 - 23:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 16.90%

AVG. WIND SPEED:

2.80 m/s

CALM WINDS:

16.90%

TOTAL COUNT:

43824 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)

DATE:

10/22/2004

WRPLOT View - Lakes Environmental Software

W IND ROSE PLOT:

Station # 93107, San Diego (Miramar)

COMMENTS:

All hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

California Air Resources 

Board

NORTH

SOUTH

WEST EAST

3%

6%

9%

12%

15% DATA PERIOD:

1967-1971 

Jan 1 - Dec 31

06:00 - 14:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 14.44%

AVG. WIND SPEED:

3.10 m/s

CALM WINDS:

14.44%

TOTAL COUNT:

16434 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)
Appendix H-2 

Appendix H 16

Figure B7 – Pasadena Wind Rose (6am – 3pm) 

Figure B8 – Pasadena Wind Rose (All Hours) 

DATE:

10/22/2004

W RPLOT View - Lakes Environmental Software

WIND ROSE PLOT:

Station # 51122, Pasadena

COMMENTS:

All hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

California Air Resources 

Board

NORTH

SOUTH

WEST EAST

3%

6%

9%

12%

15% DATA PERIOD:

1981 

Jan 1 - Dec 31

00:00 - 23:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 21.89%

AVG. WIND SPEED:

1.62 m/s

CALM WINDS:

21.89%

TOTAL COUNT:

8760 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)

DATE:

10/22/2004

W RPLOT View - Lakes Environmental Software

W IND ROSE PLOT:

Station # 51122, Pasadena

COMMENTS:

6am to 3pm hours reporting.

PROJECT NO.:

MODELER:

COMPANY NAME:

California Air Resources 

Board

NORTH

SOUTH

WEST EAST

4%

8%

12%

16%

20% DATA PERIOD:

1981 

Jan 1 - Dec 31

06:00 - 14:00

WIND SPEED

(m/s)

>= 5.4

3.3 - 5.4

1.8 - 3.3

0.5 - 1.8

Calms: 16.44%

AVG. WIND SPEED:

1.58 m/s

CALM W INDS:

16.44%

TOTAL COUNT:

3285 hrs.

DISPLAY:

 Wind Speed

Direction (blowing from)
Appendix H-2 

Appendix H 17

Modeling 

Chrome Plating with a stack source, unit emission rate 

q (g/s) days/week q (g/yr) q (lb/yr) 

1 7

 

11,793,600 

 

26,000 

 

(m) (ug/m3) (ug/m3) (ug/m3) 

Distance from 

edge of facility Fresno 

San Diego, 

Inland Pasadena 

20 

Low n/a n/a n/a

Medium n/a n/a n/a

High n/a n/a n/a

Horizontal 180.00 220.00 470.00

30 

Low 61.00 71.00 130.00

Medium 43.00 49.00 52.00

High 17.00 20.00 25.00

Horizontal 130.00 150.00 320.00

40 

Low 54.00 64.00 120.00

Medium 41.00 47.00 53.00

High 23.00 27.00 38.00

Horizontal 87.00 110.00 220.00

50 

Low 44.00 53.00 100.00

Medium 36.00 41.00 50.00

High 23.00 27.00 39.00

Horizontal 63.00 75.00 150.00

100 

Low 16.00 20.00 38.00

Medium 15.00 17.00 28.00

High 13.00 15.00 25.00

Horizontal 19.00 22.00 43.00

200 

Low 4.70 5.40 11.00

Medium 4.40 5.20 9.60

High 4.10 4.80 9.00

Horizontal 4.90 5.60 11.00

500 

Low 0.80 0.90 1.70

Medium 0.80 0.90 1.70

High 0.70 0.80 1.60

Horizontal 0.80 0.90 1.80

1000 

Low 0.20 0.20 0.40

Medium 0.20 0.20 0.40

High 0.20 0.20 0.40

Horizontal 0.20 0.20 0.40
Appendix H-2 

Appendix H 18

ISCST (Version 02035) Model Results 

In addition to the details in the figures, the following met. Data 

are used to estimate long term (annual) averages) 

These data are the latest available processed databases. 
Appendix H-2 

Appendix H 19

Modeling 

Chrome Plating with fugitive source, unit emission rate 

q (g/s) hrs/day days/week q (g/yr) q (lb/yr) 

1 9 7 11,793,600 26,000 

 

|--------- period 

(annual) average ----

---------------------------

---l 

(m) (ug/m3) (ug/m3) (ug/m3) (ug/m3) 

Distance 

from edge 

of facility Oakland Fresno 

San Diego, 

Inland Pasadena 

20 

small 180.00 180.00 220.00 420.00

medium 140.00 140.00 220.00 340.00

large 97.00 95.00 120.00 230.00

30 

small 110.00 110.00 130.00 250.00

medium 83.00 83.00 100.00 190.00

large 66.00 65.00 83.00 150.00

40 

small 70.00 70.00 85.00 160.00

medium 58.00 58.00 71.00 130.00

large 48.00 47.00 59.00 110.00

50 

small 50.00 50.00 60.00 120.00

medium 45.00 45.00 54.00 100.00

large 36.00 36.00 44.00 81.00

100 

small 17.00 17.00 20.00 39.00

medium 17.00 17.00 20.00 38.00

large 17.00 17.00 20.00 38.00

200 

small 4.70 4.70 5.30 10.00

medium 4.70 4.70 5.30 10.00

large 4.70 4.60 5.30 10.00

500 

small 0.80 0.80 0.90 1.70

medium 0.80 0.80 0.90 1.70

large 0.80 0.80 0.90 1.70

1000 

small 0.20 0.20 0.20 0.40

medium 0.20 0.20 0.20 0.40

large 0.20 0.20 0.20 0.40
Appendix H-2 

Appendix H 20

ISCST (Version 02035) Model Results 

In addition to the details in the figures, the following met. data are 

used to estimate long term (annual) averages) 

These data are the latest available processed databases. 
Appendix H-2 

Appendix H 21

REFERENCE 

ARB Compilation of Emission Testing Results from Chromium Plating and Chromic 

Acid Anodizing Facilities