Date: May 25, 2010 

Subject: Estimated Number of Chromium Electroplating Plants 

Emission Standards Technical Support and Post Promulgation Activities 

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

RTI Project No. 0210426.004.006 

From: Richard Marinshaw 

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

The purpose of this memorandum is to provide the basis for the estimated 1,770 plants in 

the U.S. that are subject to the national emission standards for hazardous air pollutants 

(NESHAP) for Hard and Decorative Chromium Electroplating and for Chromium Anodizing 

Tanks (40 CFR 63, subpart N). Section I of this memorandum describes the data used to develop 

the estimated numbers of plants, and Section II explains how the estimates were derived. 

I. Background

 RTI International (RTI) began compiling data on the chromium electroplating industry in 

June 2003 under Work Assignment 1-18 of EPA Contract No. 68-D-01-079. Data were obtained 

from EPA Regional Offices, State and local agencies, and several databases, including the 

National Emission Inventory (NEI) database, the Toxic Release Inventory (TRI) database, the 

National Metal Finishers Resource Center online database, and the Thomas Register On-line. 

The data obtained from many of these information sources consisted of plant names, addresses, 

and the type of electroplating performed. In some cases, data on electroplating tank operating 

parameters also were obtained. The data were compiled in an Access database, hereafter referred 

to as the Electroplating Database. The database has been periodically updated as new data have 

become available. 

 

 In March 2004, RTI began working on the Plating and Polishing Area Source NESHAP. 

Because many of the processes and sources that were covered by the Plating and Polishing 

source category were co-located at facilities that are subject to the Chromium Electroplating 

NESHAP, the data collected for Plating and Polishing were entered into the Electroplating 

Database. In 2006, an information collection request (ICR) was developed for the Plating and 

Polishing Source Category and transmitted to more than 1,100 companies. The ICR 

questionnaire requested information on electroplating and non-electroplating processes, tank 

design and operating data, use of plating chemicals and other materials, and emission controls. 

Because tanks subject to the Chromium Electroplating NESHAP would not be subject to a rule 

for Plating and Polishing, the ICR instructed plants to indicate if the plant performed chromium 

electroplating, but respondents were not required to provide any further data on chromium 

electroplating operations. 

 
2 

When the Plating and Polishing ICR mailing list was developed, the Electroplating 

Database included information on approximately 2,600 plants. For about 1,200 of the plants, the 

available information indicated that the only type of electroplating performed at the plant was 

chromium electroplating. Those plants were screened out of the mailing list for the Plating and 

Polishing ICR. After further screening of the data, a final mailing list was prepared. The 

mailing list included about 1,150 companies, representing just over 1,200 plants. The ICR was 

transmitted in May 2006, and a total of 606 ICR questionnaires were completed and returned to 

EPA. In other words, data were received for approximately 50 percent of the plants that were 

sent questionnaires. Approximately 100 questionnaires were returned to EPA as undeliverable; 

and EPA was informed that roughly another 100 plants were either closed or did not perform 

plating or polishing; the status of the other 400 plants that were sent questionnaires is unknown. 

After updating the Electroplating Database to account for the 200 plants that are either closed, do 

not perform electroplating, or were undeliverable, the Electroplating Database included 

information on 2,417 plants that were assumed to be in operation. Of these, 1,171 plants were 

indicated as performing only chromium electroplating (chromium only plants), and 1,246 plants 

were indicated as performing some other type of electroplating (other electroplating plants). 

However, it was unknown the type of chromium electroplating performed by the 1,171 

chromium only plants, and it was unknown how many of the other electroplating plants 

performed chromium electroplating. Using the data on electroplating process type that were 

available for some of the plants, and the data compiled for the Plating and Polishing NESHAP, 

the number and distribution of chromium electroplating plants were estimated. The following 

section describes the methodology used for the estimates. 

II. Methodology for Estimating Number of Plants Nationwide

 For the chromium only plants listed in the Electroplating Database, the type of process 

was identified for a total of 417 plants. Table 1 summarizes the distribution of these plants by 

the three process types covered by the Chromium Electroplating NESHAP. 

Table 1. Type of Electroplating Performed by "Chromium Only" Plants 

Process type No. of plants Percent of total 

Hard chromium 204 48.9% 

Decorative chromium 145 35.0% 

Chromium anodizing 67 16.1% 

Total 417 100% 

 For the other electroplating plants listed in the database, the data from the Plating and 

Polishing ICR responses were used to estimate the distribution. Although the questionnaire did 

not request detailed data on chromium electroplating, it did require plants to indicate if they 

performed chromium electroplating or anodizing. Table 2 summarizes the distribution of these 

plants according to process. 
3 

Table 2. Type of Chromium Electroplating Reported in Plating and Polishing ICR 

Responses 

Process type No. of plants Percent of total 

Hard chromium 107 17.7% 

Decorative chromium 160 26.4% 

Chromium anodizing 27 4.5% 

No chromium electroplating 312 51.5% 

Total 606 100% 

 By combining the percentages of chromium electroplating plants from the above 

distributions and applying them to the number of plants in the Electroplating Database, the 

number of each type of chromium electroplating plants nationwide was estimated. Table 3 

summarizes the results. 

Table 3. Estimated Number of Chromium Electroplating Plants Nationwide 

Process Total 

Hard 

chromium

Decorative 

chromium 

Chromium 

anodizing 

No. of chromium only plants in database 1,171 

 Percentage for each process 48.9% 35.0% 16.1% 

 Resulting number of plants 573 410 188 

No. of other plants in database 1,246 

 Percentage for each process 17.7% 26.4% 4.5% 

 Resulting number of plants 220 329 56 

Total number of plants 793 739 244 

Total (rounded to nearest 10) 1,770 790 740 240