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Anil Baral - Chromium-based regulations and greening in metal

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Chromium-based regulations and
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Anil Baral
Environmental Science & Policy
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Environmental Science & Policy 5 (2002) 121–133
Chromium-based regulations and greening in metal
finishing industries in the USA
Anil Baral a,∗ , Robert D. Engelken b
Environmental Sciences Ph.D. Program, Arkansas State University, State University, AR 72467, USA
b Department of Engineering, P.O. Box 1740, State University, AR 72467, USA
This paper reviews the regulations pertaining to chromium emissions from metal finishing industries in the USA and technical options for compliance, and assesses the influence of regulations on the reduction of chromium emissions. Based upon the literature
analysis, the paper argues that there has been discernible impact of the regulations on chromium emissions control by metal finishing
industries. Chromium emission reduction by metal finishing industries has occurred mainly in response to the need to comply with
chromium regulations. To meet the regulatory requirements, the industries have either installed chromium emission control equipment or
moved to pollution prevention by minimizing waste generation and implementing process and product modifications. Over time, metal
finishing industries have learned that pollution prevention does pay and environmental protection and pollution prevention are compatible businesses. With innovative public policy like EPA’s Common Sense Initiative (CSI) now in place, the prospects for chromium
emission reduction and compliance to regulations looks better than ever. A number of metal finishing industries, mainly large businesses, have adopted “greening” as the principal philosophy of business management. However, greening is occurring slowly because
of lack of personnel and capital resources, awareness, and technical competence, as well as organizational resistance, high costs of production, uncertainty about future regulatory activity, and substantial marketplace constraints. © 2002 Elsevier Science Ltd. All rights
Keywords: Hexavalent chromium; Trivalent chromium; Metal finishing industries; Greening; Common Sense Initiative; Waste minimization
1. Introduction
Metal finishing industries in the US constitute an important and environmentally sensitive industrial sector. There
are more than three thousand “job shops,” mostly small
businesses with limited capital and personnel, and more
than 8000 “captive” metal finishing operations that fall
within larger manufacturing facilities (EPA, n.d.). Of these,
the most notable are chromium electroplating industries
(MRI, 1995). These industries are geographically diverse
but concentrated in heavily industrialized states. Metal finishing industries, owing to the cross media impacts (air,
water and land) of their operations, have been brought under a broad range of federal, state, and local environmental
Chromium electroplating and anodizing tanks are among
the largest sources of chromium emissions in the US
Chromium(VI) or hexavalent chromium, which is commonly
∗ Corresponding author. Present address: P.O. Box 332, State University,
AR 72467, USA. Tel.: +1-870-2681074; fax: +870-972-3948.
E-mail address: b120.rm@yahoo.com (A. Baral).
used in electroplating operations, is highly toxic and a
proven carcinogen. Breathing high levels of hexavalent
chromium can damage and irritate nose, lungs, stomach, and intestine (ATSDR, 1993). Although hexavalent
chromium provides many advantageous coating properties,
it is regulated by the federal government for its toxicity and
Due to ever increasing regulatory driving forces, metal
finishing industries are facing the problem of rising manufacturing costs. This has forced many industries to pursue “greening” by implementing waste minimization, and
adopting acceptable and economically feasible alternatives
for chromium electroplating. This paper briefly describes
the health effects of chromium, chromium plating techniques, chromium emissions, and regulations pertaining to
chromium, and technological options available for compliance. It also analyzes: (1) In what ways have the environmental regulations influenced the electroplating industries
to comply with standards and go green? (2) Are there any
conflicts of interest between industries and regulators? (3),
How effective have the regulations been in minimizing
chromium emissions?
1462-9011/02/$ – see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S 1 4 6 2 - 9 0 1 1 ( 0 2 ) 0 0 0 2 8 - X
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
Fig. 1. The contributions to ambient chromium from different sources in
New England (EPA, 2001b).
2. Sources and health effects of chromium
Chromium (Cr) is found in nature in rocks, soil, plants, animals, volcanic dust, and gases (ATSDR, 1998). Chromium
occurs primarily in the trivalent state (III) and in the hexavalent state (VI). Elemental chromium(0) does not occur naturally on earth. Chromium(III) and (VI) are used for making
steel and other alloys, bricks, dyes, pigments, “chrome
plating”, leather tanning, and wood preserving (Barceloux,
1999; ATSDR, 1998). Chromium enters the air, water,
and soil mostly through chromium(III), and chromium(VI)
forms as a result of natural processes and anthropogenic
activities. A substantial portion of chromium in ambient air
in the US comes from major sources 1 (which are also point
sources 2 ), mainly industries. In its draft report of national
scale air-toxics assessments submitted for scientific peer
review, EPA estimated 1996 nationwide chromium compound emissions into air to be approximately 1150 tons per
year (EPA, 2001a). Of the total emissions, 676 tons per year
(59%) came from major sources, 423 tons per year (37%)
came from area and other sources, 3 and 48 tons per year
(4%) came from mobile 4 sources. A similar trend was found
in New England (Maine, Massachusetts, New Hampshire,
Rhode Island and Vermont) where point sources contributed
approximately 50% of the total chromium emissions into
air, which was followed by area sources (32%) and mobile
sources (18%) (Fig. 1). According to EPA’s 1996 estimates,
1 Major sources are those stationary facilities that emit or have the
potential to emit 10 tons of any one toxic air pollutant or 25 tons of more
than one toxic air pollutant per year.
2 A point source is a stationary location or fixed facility from which
pollutants are discharged; i.e. any single identifiable source of pollution
such as a pipe, ditch, or factory smokestack.
3 Area and other sources include sources that generally have smaller
emissions on an individual basis than “major sources” and are often too
small or ubiquitous in nature to be inventoried as individual sources. Area
sources include facilities that have air toxics emissions less than 10 tons
of a single toxic air pollutant or less than 25 tons of multiple toxic air
pollutants in any one year. Area sources include small businesses and
household activities such as dry cleaners. “Other sources” include sources
such as wildfires and prescribed burnings that may be more appropriately
addressed by other programs rather than through regulations developed
under certain air toxics provisions in the CAA.
4 Mobile sources are non-stationary sources of air pollution such as
cars, trucks, motorcycles, buses, airplanes, and locomotives.
New York has the highest median annual ambient concentrations of chromium (8 × 10−3 ␮g/m3 ) followed by New
Jersey (5.8 × 10−3 ␮g/m3 ), both of which represent highly
industrialized states (EPA, 2001a). According to the same
estimates, the national annual average concentration is only
3.34 × 10−3 ␮g/m3 . In the US, concentrations of chromium
in air in urban areas are higher (0.01–0.03 ␮g/m3 ) as compared to those of rural areas (<0.01 ␮g/m3 ) (Fishbein,
Human beings can be exposed to chromium by breathing
air, drinking water, or eating food containing chromium,
or through skin contact with chromium or chromium compounds. People who work in industries that process or
use chromium or chromium compounds are more likely
to be exposed to higher than normal levels. It is estimated
that 305,000 workers in the US are exposed to chromium
and chromium containing compounds in the work place
(ECO-USA, 2000). People who live near chromium waste
disposal sites or chromium manufacturing and processing plants have a greater probability of exposure to elevated levels of chromium than the general population
(ATSDR, 1998). The industries in which potential occupational exposures occur are stainless steel welding,
chromate production, chromium plating, ferrochrome,
chromium-based pigments, and leather tanning (ECO-USA,
The nature of health effects on humans is largely determined by the oxidation state of chromium. Trivalent
chromium generally has low toxicity, and the gastrointestinal tract poorly absorbs compounds containing trivalent
chromium (Anderson et al., 1983). Therefore, trivalent
chromium is of less concern from the human health point of
view than hexavalent chromium. Exposure to chromium(III)
in large amounts causes health effects such as allergies.
However, chromium(III) is also an essential nutrient. Most
people are exposed to small amounts of chromium(III) in
their food and it is required for good nutrition. Humans need
chromium(III) for normal sugar metabolism. A deficiency
of chromium(III) causes high blood fat and cholesterol
levels, as well as diabetic-like symptoms of glucose intolerance, weakness, depression, confusion, weight loss, thirst,
hunger, and frequent urination (Bookman Press, 1998). An
intake of 50–200 ␮g of chromium per day is recommended
for adults (ATSDR, 1998).
The most important concern from the human health
point of view is chromium(VI) for both acute and chronic
exposures (ATSDR, 1998; EPA, 1998a). Breathing very
high levels of chromium(VI) in air can damage and irritate
nose, lungs, stomach and intestines. The human respiratory
tract is the major target organ for chromium(VI) in the
case of inhalation exposure. Shortness of breath, coughing,
and wheezing have been reported following inhalation of
very high concentrations of chromic(VI) oxide (ATSDR,
1998; EPA, 1998a). Hexavalent chromium produces hyperemia (Meyers, 1950), ulceration, and inflammatory changes
in the mucous lining of the respiratory tract following
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
inhalation (Barceloux, 1999). It has been found that hexavalent chromium is a pulmonary sensitizer that causes
bronchoplasm and anphylactoid reactions in sensitized
workers (Moller et al., 1986). Acute toxicity testing in rats
has shown that chromium(VI) causes extreme toxicity from
inhalation (LC50 = 30–140 mg/m3 ) 5 and oral (LD50 <
100 mg/kg) 6 exposure (DHHS, 1993). Other notable effects that result from inhalation of very high concentrations
of chromium(VI) are gastrointestinal and neurological effects (EPA, 1998a; WHO, 1988). Direct skin contact with
chromium(VI) compounds causes skin burn and ulcers
(Barceloux, 1999). The acute ingestion of large amounts
of hexavalent chromium results in acute tubular necrosis 7 ,
marked interstitial changes, and renal failure (Saryan and
Reedy, 1988; Ellis et al., 1982). Similarly, a study carried
out by Kaufman et al. (1970) revealed that acute ingestion
of very large amounts of hexavalent chromium produced
hepatic necrosis.
Genotoxicty studies have shown that hexavalent chromium
compounds are the most potent genotoxins 8 (Cohen et al.,
1993). A number of epidemiological studies of workers
have established that inhaled hexavalent chromium is a
human carcinogen and can increase risk of lung cancer
(Kimbrough et al., 1999; Baetjer, 1950; EPA, 1993; Gibb
et al., 2000; Langard, 1993; Langard and Vigander, 1983;
Davies, 1984). However, the risk of cancer from dermal
or oral exposures to hexavalent chromium compounds is
not well documented. The risk of lung cancer following
exposure to hexavalent chromium was found to increase
with the duration of exposure (Hayes et al., 1989). By
using mathematical models based on human and animal
studies, EPA calculated an inhalation unit risk estimate of
0.012 ␮g/m3 (Smith, 1996) for hexavalent chromium which
correlates to an upper 95% confidence limit of 1:1,000,000
for an air concentration of 8 × 10−5 ␮g/m3 (Barceloux,
1999). Based on sufficient evidence of carcinogenicity of
chromium(VI) compounds in human and animals, the International Agency for Research on Cancer (IARC) and the
Department of Health and Human Services have treated
chromium(VI) compounds as carcinogenic compounds.
Similarly, EPA has classified chromium(VI) as a known
human carcinogen by the inhalation route of exposure
(EPA, 1993). In addition to lung cancer, several studies
suggest the possibility of cancer in non-pulmonary sites
(Davies et al., 1991; Costa, 1997; Lees, 1991) but the results of these studies are inconsistent and conclusions are
5 Median lethal concentration (LC50) is the concentration resulting in
death for 50% of exposed individuals by a predetermined time, e.g. 96 h.
6 Median lethal dose (LD50) is the dose resulting in death for 50% of
exposed individuals by a predetermined time, e.g. 96 h.
7 Necrosis refers to cell death due to disease or injury. Tubular necrosis
is the cell death in tubules of the kidney resulting in kidney failure.
8 Genotoxins are physical or chemical agents that damage genetic materials, e.g. chromosomes or DNA. In general, gentoxins lead to cancer,
mutations, and developmental malformations.
3. Chromium(VI) and metal finishing industries
Most metal finishing industries employ chromium plating to make products shiny, attractive, and wear and
tear-resistant. Chromium plating utilizes chromic(VI) acid
(CrO3 or H2 CrO4 ) baths, which yield a very hard, brilliant,
and wear and corrosion-resistant coating. Because of its
versatile properties, chromium plating has become popular since it became commercially available in the 1920s
(Groshart, 1997). Chromium electroplating can be divided
into three categories (1) hard chromium electroplating, (2)
decorative chromium electroplating, and (3) chromium anodizing. In hard chromium electroplating, a thick layer of
chromium (10 to over 300 ␮m thick) is deposited directly
on the base metal or substrate to provide wear and corrosion resistance for products such as hydraulic cylinders,
drills, reamers, industrial rolls, etc. (KOECT, 1980). A typical flow chart for hard chromium electroplating is shown
in Fig. 2. Decorative chromium electroplating typically deposits a thin layer of chromium (0.25 ␮m) on a base metal,
plastic, or undercoating to provide a bright finish and wear
and tarnish resistance for products such as bicycles, auto
trim, tools, etc. (EPA, 1984). In chromium anodizing operations, a chromium oxide layer is deposited on aluminum
to provide corrosion and wear resistance. Anodizing operations are used for aircraft parts, architectural structures, etc.
(EPA, 1995a).
The first step in chromium plating is a pretreatment step,
which can be mechanical buffing, polishing, vapor degreasing, or soaking in an organic solvent. The pretreatment
Fig. 2. A typical flow chart for hard chromium electroplating (KOECT,
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
step is followed by alkaline cleansing in order to remove
surface soil. Alkaline cleansing is accomplished by soaking
and/or electrolytic processes (EPA, 1984). In electrolytic
alkaline cleaning, gas evolution on the surface of the substrate enhances the cleaning agent’s action. After rinsing,
the base metal (e.g. steel) is dipped in acid to remove tarnish and to neutralize the alkaline film on its surface. In the
hard chromium plating operation, the cleaned substrate is
subjected to an anodizing treatment before chromium electroplating. However, for decorative chromium plating, an
undercoat of copper or nickel is applied to the base metal
before chromium plating. The anodizing treatment applies
a protective oxide film on the base metal. At the end,
the chromium layer is electrodeposited on the base metal
(KOECT, 1980; Sittig, 1975).
Plating and anodizing operations vary greatly in size from
small shops with one or two tanks that are operated for a few
hours a week to large shops with several tanks that are operated 24 hours per day, 7 days per week. Most of plating and
anodizing operations are captive shops that carry out electroplating or chromic acid anodizing as one operation within
or for a manufacturing facility. The others are job shops that
provide custom plating or anodizing services (EPA, 1989).
3.1. Chromium emissions from chromium electroplating
There are approximately 5000 facilities 9 with chromium
electroplating and/or anodizing tanks in the US. Many
of them are small shops and are within near proximity
to residential areas with high population densities. Large
numbers of chromium electroplating facilities are found in
industrialized states like California, Illinois, Massachusetts,
Michigan, New York, Ohio, and Pennsylvania (EPA, 1989).
Of the total 5020 facilities, 1540 are hard chromium electroplaters, 2790 are decorative chromium electroplaters, and
680 are chromium anodizers (EPA, 1989). Because of this
proximity, metal finishing industries are posing a serious
threat to the health of people living nearby these facilities. The EPA report (1989) estimated that total hexavalent
chromium emissions 10 were 175.8 tons per year with hard
chromium plating contributing 161 tons per year, decorative
chromium plating contributing 11 tons per year, and chromic
acid anodizing operations contributing 3.8 tons per year
(Table 1).
The main sources of chromium emissions from hard
chromium plating are chromic acid treatment and electro9 This is a 1989 estimate. The present number of facilities may be
lower than 5000 since some of them have been shut down for failing to
meet standards and other reasons.
10 Recent data on total hexavalent chromium emissions from electroplating and chromic acid anodizing operations are not available. However,
total emissions should have been reduced considerably after the implementation of MACT standards. According to the EPA projection, total
hexavalent chromium emissions would be reduced to 36 tons per year (a
reduction of about 140 tons per year from the pre-MACT period) by 1997
(Mulrine, 2001).
Table 1
Estimated hexavalent chromium emissions from chromium electroplating
and chromic acid anodizing operations in the US
No. of plants
Nationwide hexavalent
chromium emissions
(tons per year)
Hard chromium plating
Decorative chromium plating
Chromic acid anodizing
Source: EPA (1989).
plating steps (Fig. 2) whereas for decorative chromium plating, it is the electroplating step. In both decorative and hard
plating processes, the electroplating step generates mists or
aerosols of the electrolyte (mainly chromic acid). Chromic
acid mist emissions result from the inefficiency of the hexavalent chromium plating process. Only about 10–20% of
the applied current is used to deposit chromium on the
metal plated. The rest is used by hydrogen and oxygen gas
evolution that helps to form chromic acid mist. A number
of factors such as the bath temperature, the concentration
of bath constituents, the amount of work being plated, and
the plating current affect emission rates of chromium from
the electroplating step (EPA, 1984). As a result of a higher
current density used in the hard chromium plating, more
chromic acid mist is generated in comparison to the decorative chromium plating. The higher current density increases
rates of gassing thereby generating more chromic acid mist
(Sittig, 1975). Uncontrolled emission data for chromium
plating are much more limited, particularly for the case of
decorative plating processes. The studies conducted for a
limited number of plants (Table 2) suggest an uncontrolled
emission factor of 10 mg of hexavalent chromium/Ah for a
hard chromium electroplating operation and 2.0 mg/Ah for
a decorative chromium electroplating (EPA, 1989). Therefore, hard chromium electroplating is more polluting than
decorative chromium electroplating.
4. Regulations as response to threat of chromium(VI)
In response to the growing volume of evidence of the carcinogenicity of chromium(VI) which is used in electroplating operations by large number of metal finishing industries,
and potential exposure of chromium(VI) to a large number
of workers, several regulations have been put in place to
minimize the health hazard. Although hexavalent chromium
offers many advantageous properties, with the enactment
of these regulations, metal finishing industries found themselves in a situation where they would either have to improve their environmental performance or face a penalty.
Notable regulations include the Clean Air Act (CAA) as
amended in 1990, the Resources Recovery and Conservation
Act (RCRA), the Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA), the Toxic
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
Table 2
Uncontrolled emission dataa from hard and decorative chromium plating
Process conditions
No. of tanks
Hard chromium plating
Plant Ab
Plant Bb
Plant Cc
Plant Db
Plant Ed
Plant Fb
Plant Gb
Plant He,f
Decorative chromium plating
Plant Ig
Plant Jh
Total tank surface
area (m2 )
Actual gas flow
rate (m3 /min)
Mass emission rate (kg/hr)
Total Cr
Process Cr+6 emissions
rate (mg/Ah)
All tests were performed by EPA except for Plant D.
Ah and mass emission rate values are based on an average of three test runs.
c Ah and mass emission rate values are based on an average of four test runs.
d Ah and mass emission were not reported.
e Ah and mass emission rate values are based on an average of 12 test runs.
f Preliminary test data.
g Total chromium emissions were not determined.
h Not included in average value because data are based on total chromium.
i Hexavalent chromium emissions were not reported. Source: EPA (1989).
Substances Control Act (TSCA), and the Drinking Water
Act. In addition, chromium(VI) has been regulated directly
or indirectly by government agencies such as the Occupational Safety and Health Administration (OSHA), and
the National Institute for Occupational Safety and Health
4.1. The Clean Air Act
The CAA amended in 1990 provides the mandate to
EPA to regulate emissions of 189 toxic chemicals including chromium compounds from a wide array of industries.
With respect to metal finishing industries, EPA is regulating
emissions of chromium from electroplating and anodizing
tanks in order to meet the requirement of the CAA. As
required by the CAA amendments, EPA put in place the
maximum achievable control technology (MACT) standards
for electroplaters and anodizers. It is expected that if full
compliance was achieved using MACT, the new regulation
would result in a reduction of about 173 tons of annual
chromium emissions into the air, which is equal to a 99%
reduction from the pre-MACT period (MRI, 1995).
This regulation affects all facilities that use chromium
electroplating or anodizing tanks, irrespective of size. The
regulation, which is an integrated approach to emission
control, specifies emission limits, work practices, initial performance testing, ongoing compliance monitoring, record
keeping, and reporting. The regulation specifies emission
limits (expressed as concentration of chromium in mil-
ligrams per day per standard cubic meter (mg per day m3 )
of exhaust air) that can be achieved by use of emission
control techniques. The emissions limits set by the EPA
are given in Table 3. The implication of the CAA is that
it increases the cost of controlling numerous air emissions
produced by metal finishers, increasing incentives for waste
In terms of the total nationwide capital costs, it is estimated that implementation of the MACT standards cost US$
41 million for existing hard chromium plating facilities. The
nationwide annualized cost is estimated at US$ 17 million
for hard chromium plating facilities. However, no capital
costs or increased annualized costs are expected for existing decorative chromium plating and chromium anodizing
operations (EPA, 1994a). The use of fume suppressants in
decorative chromium plating and anodizing operations reduces the generation of chromium mists to levels that meet
MACT standards. Therefore, these operations do not need
add-on pollution control devices (Banker, 2001).
Table 3
MACT standards for electroplating and anodizing tanks
Emission limits
Small hard chromium electroplating tanks
Other hard chromium electroplating tanks
Decorative chromium electroplating
and chromium anodizing tanks
0.03 mg per day m3
0.015 mg per day m3
0.01 mg per day m3 or a
surface tension limit of
0.045 kg/s2 (45 dyn/cm)
Source: MRI (1995).
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
Table 4
Standards and regulations for chromium
0.05 mg/m3
Advisory: TWA to avoid carcinogenic risk
from certain insoluble chromium compounds
Metal and Cr(III) compounds
Water-soluble Cr(VI) compounds
Insoluble Cr(VI) compounds
Chromite ore (chromate) as Cr
Zinc chromates as Cr
Increase during shift
End of shift
Advisory: TWA (10 h) for carcinogenic Cr(VI) salts
Regulation: permissible exposure limit (PEL) for
chromic acid and chromate (ceiling)
PEL for soluble chromic salts (8 h TWA)
PEL for chromium metal and insoluble salts (8 h TWA)
Regulation: current maximum contaminant level
(MCL) for total chromium; proposed MCL is 100 ␮g/l
Regulation: CAA (MACT standard)
Drinking water
0.5 mg/m3
0.05 mg/m3
0.01 mg/m3
0.05 mg/m3
0.01 mg/m3
10 ␮g/g
30 ␮g/g
1 ␮g/m3
100 ␮g/m3
500 ␮g/m3
1000 ␮g/m3
50 ␮g/l
0.01–0.03 mg per day m3
depending upon the types of
chromium electroplating tanks
Hazardous materials/waste
TSCA: reporting threshold is 10,000 lb per year
RCRA: requires to certify that waste generators have a
program in place to reduce the volume or quantity and
toxicity of the waste they generate
CERCLA: liability for released hazardous waste
Source: Modified from Barceloux (1999).
4.2. Other EPA regulations
EPA regulates chromium and its compounds under the
Clean Water Act. EPA has set a maximum contaminant
level (MCL) of 50 ␮g/l for total chromium in drinking water (Barceloux, 1999). In addition, EPA regulates chromium
under the CERCLA amended in 1986 with the Superfund
Amendments and Reauthorization Act (SARA), the Resource Conservation and Recovery Act (RCRA), and the
Toxic Substances Control Act (TSCA).
The CERCLA, amended in 1986 with SARA mandates
EPA to respond to hazardous waste releases, require clean-up
of hazardous waste sites, and assign liability for released
hazardous waste (Newman, 1998). The RCRA requires all
hazardous waste generators, including metal finishing industries, to certify that they have a program in place to reduce
the volume or quantity and toxicity of the waste that they
generate. Waste generators must manage hazardous wastes
in accordance with RCRA’s on-site waste management
requirements or obtain a permit for waste management
activities. They must also verify that the transportation,
treatment, storage, and disposal of their waste are conducted
only by others with EPA identification numbers and authority to manage the waste. The TSCA regulates the manufacture, processing, transport, use, import, and disposal of
chemicals or chemical mixtures including chromium compounds that pose an unreasonable risk to human health or
the environment (Newman, 1998). It places emphasis on the
quality and quantity of toxic substances being produced. It
requires reporting if production or use of harmful chemicals
exceeds 10,000 lb (4500 kg) per year.
4.3. The Occupational Safety and Health Administration
OSHA sets the limits for an 8 h workday, 40 h workweek as 500 ␮g/m3 of air for water-soluble chromium(III) or
chromium(II) salts and 1000 ␮g/m3 for metallic chromium
and insoluble salts. Chromic acid and chromic(VI) compounds, on the other hand, should not exceed 100 ␮g/m3 for
any period of time (ATSDR, 1993).
4.4. The National Institute for Occupational
Safety and Health
NIOSH recommends that exposure to chromium(0),
chromium(II), and chromium(III) should not exceed
500 ␮g/m3 for a 10 h workday, and 40 h workweek. NIOSH
views all chromium(VI) compounds as potential occupational carcinogens and suggests an exposure limit of 1 ␮g/m3
for a 10 h workday and 40 h workweek (ATSDR, 1993).
4.5. American Conference of Governmental Industrial
Hygienists (ACGIH)
ACGIH recommends that time-weighted average (TWA)
concentration 11 for chromium and chromium compounds
11 Time-weighted average concentration for a normal workday and 40 h
workweek to which nearly all workers may be repeatedly exposed.
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
should not exceed 0.05 mg/m3 in the workplace (Barceloux,
1999). The TWA concentration is taken to avoid carcinogenic risk from certain insoluble chromium compounds. It
also recommends that concentrations in workplace air should
not exceed 0.5 mg/m3 for Cr and Cr(III) compounds,
0.05 mg/m3 for water-soluble Cr(VI) compounds, 0.01 mg/
m3 for insoluble Cr(VI) compounds, and 0.05 mg/m3 for
chromite ore as chromium (Table 4).
5. Options for compliance
The ever-increasing regulatory requirements have forced
metal finishing industries to look for acceptable and cost
effective options. The options vary from pollution control
to pollution prevention. This section discusses some of the
current and future options that should enable electroplating
industries to meet a wide array of regulations.
Some pollution control techniques that can be employed
by chromium electroplating industries include the use of
fume suppressants, packed-bed scrubbers, composite mesh
systems, and fiber-bed mist eliminators to reduce emissions
of chromium. The majority of industries are relying on emission control technologies rather than switching to cleaner
technologies or waste minimization as a means of achieving compliance. However, in recent years there has been
growing interest in cleaner alternative technologies among
industries and researchers. Many environmentally-friendly
alternative materials and deposition methods that reduce
hazards associated with hexavalent chromium are now being used by industries and/or are in the process of being
developed. The need to develop other alternative techniques
has not been fueled only by public health, safety and, environmental concerns about hexavalent chromium. There are
certain inherent disadvantages of hexavalent chromium plating baths. They require high average cathode current densities (13.5–16.5 A/dm2 ). They have poor coverage power
(i.e. lack ability to plate low density areas such as around
holes and slots) and poor throwing power (i.e. poor metal
distribution). They exhibit burning effects (gray deposits)
at high current density areas and produce non-uniform
off-colored deposits when the plating current is interrupted; this is also known as “white washing” (Gianelos,
The promising alternatives include trivalent chromium
electroplating, metallic and alloy electroplating, electroless
plating, chemical vapor deposition (CVD), thermal spraying,
and vacuum coating. None of earlier-mentioned alternatives
can match the unique properties of chromium electroplated
from hexavalent chromium. However, not all applications require all of the properties of hexavalent chromium coatings.
For example, chromium bushings do not require the bright
metallic appearance of hexavalent chromium and the decorative automotive trim does not require the wear-resistant
properties (Groshart, 1997). Such applications are where alternative plating techniques may be useful.
• Trivalent chromium electroplating: Trivalent chromium as
an alternative coating material has been extensively studied (Hsieh et al., 1993; Edigaryan and Polukarov, 1998;
Hwang, 1991). Even some metal finishing industries are
using it as a replacement of hexavalent chromium. Recent studies have shown that trivalent chromium can provide comparable physical properties such as corrosion
and wear resistance, and almost the same color as hexavalent chromium while reducing operating costs, and
health, safety and environmental hazards. However, its
full adoption by industry has been hampered by the lack
of quality control, and deposits often exhibit stress, cracking, softness, and poor general appearance. Some electroplating baths have contained highly hazardous species
such as thiocyanate (Hsieh et al., 1993). Moreover, it
is more sensitive to contamination than the hexavalent
chromium process and it cannot plate the full range of
thicknesses that the hexavalent chromium process does
(EPA, 1989).
• Metallic and alloy electroplating: Electroplating of metals such as zinc, and alloys such as molybdenum–
zinc, molybdenum–nickel, nickel–cobalt, nickel–tungsten,
nickel–tungsten–boron, nickel–tungsten–silicon carbide,
nickel–zinc, and zinc–tin has been extensively studied
(Klingenberg, 1999; Stepanova and Purovaskya, 1998;
Ghahin, 1998; Takada, 1991). Wear-resistant electroplated alloys can replace chromium (Groshart, 1997).
Alloys can provide different physical and mechanical properties by combining different metals so that
chromium plating can be replaced in certain applications (CTC, 1994). Metallic and alloy electroplating has
certain advantages over chromium electroplating, for
example, uniform coating, increased energy efficiency,
and ease of automation. Recently, many articles on alloy
plating have shown such coatings to have good wear and
build-up properties but many scale-up problems have
kept them from becoming commercial. However, with the
growing volume of research in alloy electroplating with
transition metals, it can be anticipated that development
of an alloy as a satisfactory alternative to chromium is
• Electroless plating: It is a coating process in which metal
ions are catalytically deposited from dilute solutions
onto a “sensitized” substrate through a continuous redox
reaction involving reduction of ions by reducing agents
such as hypophosphite or borohydride. The most widely
used electroless plating materials are nickel and copper
although certain other metals or alloys can be deposited
(CTC, 1994). Electroless nickel coatings have excellent
wear and resistant properties and are used in a wide range
of applications. Electroless nickel coatings often contain
phosphorus or small amounts of boron from the reducing
agents but provide desirable properties. Greater aqueous
corrosion resistance is provided by coatings with higher
phosphorus contents (Talaat El-Mallah, 1993) though
good corrosion resistance is exhibited by low phosphorus
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deposits in alkaline solution. In the case of electroless
plating, care must be taken with regard to hazardous
vapors and corrosive metals.
• CVD: It is a useful alternative to chromium-based electroplates in terms of wear resistance. In this process, a
coating is applied onto a substrate by a reactive vapor
which generally includes a metal halide, metal carbonyl
hydride, or organometallic compound. CVD provides
thick, dense and high purity coatings on substrates (CTC,
1994). There are three main types of CVD technologies: atmospheric, low-pressure, and plasma-enhanced
technologies. The advantage of the CVD process is
that it can effectively coat complex substrates (CTC,
1994). The most commonly used materials in CVD
coatings are nickel, tungsten, chromium, and titanium
carbide (EPA, 1995a). The main drawback of this process is that temperature-sensitive substrates can not be
coated since high temperatures are produced during the
• Thermal spraying: Thermal spraying technology is rapidly
gaining recognition in metal finishing industries. In thermal spraying, a coating material is melted and directed
towards a substrate with compressed air or gas. Some
examples of thermal spraying are atmospheric thermal
spraying, electric arc spraying, plasma spraying, detonation gun spraying, and high-velocity oxygen fuel spraying. In plasma spray, a gun passes the coating material to
be applied through a very hot plasma at a very high velocity. The emerging powder particle, which is in a molten
state, is blasted against the part and welded into a coating (Groshart, 1997). In plasma spraying, the coatings
which are used to provide a wear surface are tungsten
carbide-18 cobalt, cobalt-28 molybdenum-8 chromium-3
silicon alloy, cobalt-25 chromium-10 nickel-8 tungsten
alloy, and oxides of aluminum (Al2 O3 –TiO2 ) and zirconium (ZrO2 –5CaO) (Groshart, 1997). These coatings offer better wear and corrosion resistance than chromium.
The disadvantages of plasma spraying are that it is very
expensive, requires new training for applications, and can
not be used for all applications.
• Vacuum coating: In vacuum coating, positive ions or neutral atoms are used to bombard a substrate with coating material. Examples of vacuum coating technologies are ion
assisted deposition (IBAD), ion implantation, ion plating,
thermal evaporation, and sputtering (CTC, 1994). Vacuum coating is a versatile and environmentally-friendly
technology as any element or alloy that can be vaporized, evaporated, or sputtered may be used for coating
the substrate. For example, titanium nitride has been deposited as a wear coating on cutting tools by a vacuum
coating process as a substitute for chromium for the past
few years (Groshart, 1997). Vacuum deposited coatings
have improved adhesion and film structure (CTC, 1994).
However, the use of vacuum coating technologies is constrained by high capital costs and line-of-sight restrictions
for complex substrates.
In summary, replacing decorative or wear and tear-resistant
properties of chromium may not be difficult considering the
rapid development in coating technologies. However, for
the replacement to occur rapidly and realize environmental
benefits fully, alternative coating technologies and processes
not only have to yield desirable coating properties but also
be cost-competitive.
In addition to switching to environmentally benign technologies, metal finishing industries can practice simple
measures such as housekeeping changes, minor in-plant
modifications, and reuse or recycling of industrial wastewater and treatment residues, spent plating and processing
baths, spent process bath, spent cleaners, and waste solvents
in order to increase the capacity to meet standards. There
are plenty of opportunities for electroplating industries to
choose the right combination of techniques to meet the
environmental regulations if they are willing to do so.
6. Regulations as motivation for greening
It is evident from the previous discussions of regulations
that metal finishing industries are required to improve overall environmental performance in order to meet the standards
and avoid penalty or charges which otherwise they would
have to face. Metal finishing industries have responded to
the regulations in various ways. A number of possibilities
have emerged for such industries to control chromium emissions into air, water and land. These include investment in
new pollution control technology, upgrading existing technology, switching to environmentally friendly and less polluting technologies, and waste minimization. Contrary to the
conventional notion that pollution control increases the cost
of production and renders industries in a disadvantageous
position in the competitive market, many industries are finding out that pollution control could save them money. It
means that regulations can be an incentive for industries to
reduce pollution and become green. In fact, stricter standards
may drive metal finishing industries to seek viable technological solutions without a substantial investment. There is
some evidence and strong argument that stricter environmental regulations spur innovations that render businesses
additional competitive advantage in today’s world market
(Porter and Van der Linde, 1995).
6.1. Case studies
We would like to support the above argument by presenting a few case studies. An unspecified electroplating plant
(EPA, 1995b) located in New Jersey, USA, does decorative
chromium plating. It employs 48 people and has annual revenues of >US$ 1.0 million. Chromic acid(VI) solutions were
originally used in the plating bath. The company used to
generate 68 kg per week of used plating bath (EPA, 1995b).
This used bath was treated by conventional precipitation of
chromium and the resulting sludge was disposed of off-site.
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
In order to reduce the hazardous sludge obtained from the
treatment of spent solution containing hexavalent chromium,
the plant used a plating bath containing chromium(III) at
lower concentrations. Originally, 3.79 l of used bath containing 0.91 kg of Cr(VI) generated about 3.22 kg of the sludge
when treated. However, after switching to Cr(III), 3.79 l of
used bath generated 0.14 kg of sludge when treated (EPA,
1995b) so the company was able to record a substantial reduction in the amount of sludge which was regulated as hazardous waste under the RCRA.
In order to shift from Cr(VI) to Cr(III) technology, the
company invested US$ 46,000. But the benefits accrued from
this shift saved more money for the plant while helping it to
meet the more strict requirements for the hazardous sludge.
The benefits are US$ 16,000 per year savings in equipment
and US$ 19,000 per year savings in treatment costs including
the materials and labor (EPA, 1995b). The other benefit is
reduced liability by reducing the quantity of hazardous waste
generated. Regulatory compliance has become easier with
the reduction in quantity of sludge produced.
Another example is National Chromium Co. Inc., located in Putnam, Connecticut, which improved its performance while meeting its environmental responsibilities. In
1988, National Chromium faced an uncertain future. Its
antiquated facility had severe ground contamination and
substantial chromium air emissions (NEWMOA, 1996). Its
wastewater treatment system failed to satisfy state regulators. It became obvious that without major investment in
new process equipment and pollution control technologies,
the business would not survive. Moreover, the condition of
the site and the status of legal actions filed by the state
made it difficult for the company to secure external financing
(NEWMOA, 1996).
With no viable options in sight other than closing down,
National Chromium reached an agreement with the Connecticut Department of Environmental Protection based
on a credible plan to achieve compliance. The company
decided to invest in a new plant and equipment in exchange for greater flexibility in clean-up. The company
completed a new facility incorporating structural design
features, upgraded production equipment, and refined
process techniques to minimize raw materials and maximize recycling. This innovation resulted in significant
savings in plant heating costs, water usage, and raw materials. The new operations eliminated the source of site
contamination, reduced chromium emissions by 99.5%
and, improved the effectiveness of wastewater treatment
(NEWMOA, 1996).
7. Conflict of interests
However, not all industries are at the forefront of greening
or moving towards pollution prevention. There are still facilities, which either because of ignorance or unwillingness
to change, have failed to meet requirements. This has cre-
Fig. 3. Status of compliance of chromium electroplating and anodizing
operations in the EPA Region III (EPA, 2000).
ated conflicts of interest between industries and regulators.
These facilities still view pollution control as externalities
and add-on costs to production. Despite the advantage of
building a good public image, some industries are disobeying or ignoring the environmental regulations. For example,
as shown in Fig. 3, in the EPA Region III which is comprised of Delaware, Maryland, Pennsylvania, Virginia, West
Virginia and the District of Columbia, it has been found that
about 40% of facilities violated the MACT standards (EPA,
The environmental news release of EPA reports alleged
violations of chromium emissions by a number of industries in 1999 (EPA, 1999a). In 1999, EPA Region V fined
Yale Polishers and Platers Inc. US$ 500 for failing to meet
federal regulations on chromium and state clean air regulations at the company’s electroplating plant (EPA, 1999a).
An even larger penalty (US$ 128,807) was proposed by EPA
against Springfield Electroplating Company Inc. in Vermont
for failing to meet testing, monitoring, work practice, and
record keeping requirements for its decorative electroplating
tanks. The penalty against Springfield Electroplating Company came after a June 1997 EPA inspection of the plant.
The move to impose fines on the company was part of the
larger initiative, which also includes assisting companies that
clean or finish metal, and providing education on environment regulations to create an incentive for industries to exercise pollution prevention. Other metal finishing industries,
which faced administrative complaints from EPA, are Tri K
Cylinder Service Inc. Michigan, A&W Custom Chrome Inc.,
Michigan, Berkshire Manufacturing Corp., Massachusetts,
and Saco Defense Inc.—a gun manufacturer in Maine. In the
latter case, EPA proposed a US$ 195,945 penalty for failing
to meet environmental standards regarding chromium emissions (EPA, 1999a).
The multitude of industries which are violating the environmental regulations points to the fact that transition to
“greening” is not as satisfactory as has been envisioned. EPA
has classified metal finishing industries to four tiers based
on environmental performance. While industries which are
in compliance with regulations belong to tiers 1 and 2,
the industries which are not in compliance belong to tiers
3 and 4. Tier 3 industries, as EPA describes, are finishing firms that are older and want to close operations, but
stay in operation because they fear the liability and legal consequences of shutting down. EPA describes tier 4
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metal finishing industries as firms that are out of compliance or “outlaw” firms that are not substantial competitors
but tarnish the reputation of the industry. They have little
or no interest in complying with environmental regulations
(EPA, 1994b).
Most of industries in tier 3 have little ability to improve due to lack of capital, information, and skills. Tier
4 firms on other hand ignore compliance requirements and
have no incentive to improve their operations because they
gain no competitive advantage. Since they are difficult to
track down and generally escape enforcement attention,
either because of their small size and transient nature or
the inability of authorities to proceed against them, they
are not afraid of operating without compliance. They run
their business without permits and do not report discharges.
They profit by having a lower cost structure that undercuts the higher tier firms who are in compliance (EPA,
1994b). Some industries belonging to tiers 3 and 4 are operating even in the face of diminishing profits because of
high environmental clean-up costs associated with shutting
down and liquidating. Since these industries have little or
no internal capital and can not secure external financing to
carryout clean-ups, they represent a significant barrier to
pollution control that might have higher short-term costs
(EPA, 1994b).
Researchers have found that there are critical differences between leading-edge, large companies that have
launched remarkable greening initiatives and small- and
medium-sized businesses that exhibit an absence of equally
dramatic change (Hart, 1997). This is because small and
medium sized businesses are constrained by lack of many
of the requisite environmental competencies of the larger,
more professionally managed and well-financed companies
(Marcus and McEvily, 1999). The available literature suggests lack of personnel and capital resources, awareness
and technical competence, organizational resistance, high
costs of production, uncertainty about future regulatory activity, and substantial marketplace constraints as the causes
of slow progress towards greening (Press and Mazmanian,
2000; NEWMOA, 1997). It seems that industries have little
or no incentive to invest in pollution abatement or go green
so long as society does not hold them accountable for the
damage caused to public health or environment. For them,
it makes little sense to take on the burden of expenses of
pollution abatement or production line modifications as
long as they can avoid the cost of pollution. This is why the
penalties imposed by the EPA assume greater importance.
By imposing fines or charges, it is possible to internalize
the cost of environmental pollution. For these to be very
effective, the penalty or fines should be substantial so that
they provide an incentive for industries to go for pollution
prevention or control. However, the problem is that imposing such costs becomes possible only when there are
strong and effective environmental regulations, monitoring,
and enforcement, which in turn require the most committed
8. Policy innovation: Common Sense Initiative
Because of their roles in air, water and land pollution,
metal finishing industries have been the target of vigorous
command–control regulations in the campaign for pollution reduction. However, as previous discussions show, this
effort failed to bring all metal finishing industries under
compliance. The failure caused EPA to reinvent its policy
dealing with metal finishing industries and look for strategy
where a broad consensus can be reached among regulators
and metal finishing industries. This innovative public policy is known as the Common Sense Initiative (CSI). Much
of the work with metal finishing industries is being done
through EPA’s Metal Finishing Strategic Goals Program under the CSI. The CSI is an important public policy based
on the participatory concept and has tried for the first time
to address environmental management by industrial sector
rather than by the conventional approach of pollution prevention based upon environmental media (air, water and land)
(EPA, 1999b).
The CSI was created in 1994 to establish a collaborative
forum for testing innovative ideas and creating new tools
with which EPA and its partners could build environmental
management strategies for entire sectors of the US economy. The CSI is an innovative strategy to develop cleaner,
cheaper, and smarter approaches to protecting the environment and public health by involving key stakeholders such
as business, labor, environmental groups and state officials
(EPA, 1999a). The advantage of involving all stakeholders up-front is that it can avoid costly litigation in court,
thereby paving the way for faster and cost effective results
(Rosenbaum, 2000). Under this initiative, EPA is helping
the industries that have shown interest in reducing pollution to meet the standards through various projects. EPA
has formed six subcommittees representing automobile manufacturing, computers and electronics, iron and steel production, metal finishing, petroleum refining, and printing
to address environmental problems facing each of these
In the case of metal finishing industries, the CSI’s collaborative process has produced some specific new strategies for the metal finishing sector based upon the lessons
learned from the 14 projects implemented by the metal finishing subcommittee (EPA, 1999c). The goals of 14 projects
have been to provide incentives, training, education, tools,
and access to information and capital in order to remove barriers for facilities to improve environmental performance.
Some CSI metal finishing projects are designed to address
the unique needs of tiers 3 and 4 firms, whereas others look
into cross-sectional issues such as regulations, research, reporting, and pretreatment. For example, to assist tier 3 firms
to pursue environmentally sound transition of their property, rather than abandon their sites upon closure without
clean-up due to lack of capital, various EPA headquarters
and regional offices are developing pilot and program plans
to develop a “brown-field prevention exit strategy” for tier 3
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
firms based on the studies of tier 3 firms in four states (EPA,
1998b). To tackle the problems caused by renegade tier 4
firms, the tier 4 Facility Enforcement Project has been implemented to develop a sector-based, targeted enforcement
program for government at all levels to identify tier 4 firms
and take appropriate actions against them (EPA, 1998b).
The voluntary quantitative goals agreed to by the metal
finishing industries reflect a new approach in how that sector
approaches environmental performance. The commitment
shown by over 360 companies, 19 states, and 60 publicly
owned treatment works (POTWs) that recently signed up to
pursue the CSI’s metal finishing goals has created a foundation for future sector-based strategies (EPA, 1999c). It is
expected that these goals could affect as many as 11,000 industries nationwide and cut the industry’s toxic emissions
by 75% (EPA, 1998c). The important result of the CSI is that
it has brought improvement in historically adversarial relationships among many businesses, environmentalists, and
government regulators at federal, state, and local levels.
However, the CSI has its share of drawbacks. The CSI
procedure has turned out to be annoyingly time consuming.
It requires a lot of time to collect and analyze data, and
there are difficulties for stakeholders in reaching consensus on the approaches required to address complex issues
or policies. Besides, there are variations in the stakeholder’s
commitments of time and understanding of the technical issues (GAO, 1997). Recommendations evolved from the CSI
so far have been far fewer than the EPA had expected. Recently, based on the lessons learned from sector program
evaluations, plus the input of many stakeholders within EPA
and outside the Agency, EPA has developed the “EPA Sector Program Plan 2001–2005” which aims to complete the
transition from an experimental phase to the routine use
of sector approaches as part of the agency’s mainstream
The success of the CSI depends on how successful the
EPA will be in building action plans based on experiences
of the CSI projects and implementing the sector-based
approaches that will create a lasting sector-based approach
capable of achieving cleaner, cheaper, and smarter environmental and public health solutions. The success of the CSI
also means more and more industries complying with environmental regulations. It, therefore, becomes important that
the EPA address issues such as stakeholder involvement in
sector-based approaches, the role of the CSI Council over
time, and how the future of the CSI should integrate into
the EPA’s new sector-based approach.
9. Conclusions
There are no available data on how much reduction in
chromium emissions has been achieved from metal finishing
sector alone. However, it can be safely inferred that there
might have been significant reductions in chromium emissions by chromium electroplating and anodizing facilities
as exemplified by the fact that 60% of those industries in
EPA Region III are in compliance with environmental regulations and that similar trends are expected for the other
regions. EPA predicts that if full compliance was obtained
nationwide, chromium emissions into air would decrease by
173 tons per year from the pre-MACT period to 2 tons per
year. Emissions are expected to decline further as more metal
finishing industries benefit from the ongoing CSI. The major factors behind this substantial reduction is the multitude
of regulatory forces that drove industries to adopt pollution
prevention approach in their production schemes and EPA’s
willingness to help the polluting metal finishing industries
which are committed to environmental quality management
and the philosophy of greening.
The example of the CSI illustrates how greening in metal
finishing industries can be encouraged by implementing
public policy that aims at reducing costs and barriers associated with bringing like industries together in order to
overcome technological, managerial, and market place barriers to greening. It also underscores the point that if the
transaction costs of greening can be reduced for a given
industry through cost sharing and horizontal integration of
technical expertise (Press and Mazmanian, 2000), it is more
likely for industries to go “green” voluntarily.
Looking over the experience of metal finishing industries
over the last two decades, it becomes apparent that more
industries are in the position to make tremendous strides
toward greening due largely to various options now available to industries. The innovative progress made in product
designs, production processes, and technologies has made
it easier for the industries to go green. However, greening
is not uniform among large, medium and small metal finishing businesses and is pursued by mainly by large businesses. Greening is occurring slowly as the struggle between
businesses and regulators is still occurring over traditional
command-and-control environmentalism and more flexible
mechanisms like the CSI are yet to become fully effective.
The authors gratefully acknowledge ongoing support
from the US Environmental Protection Agency/Arkansas
EPSCoR program through the grant “Pollution Prevention and Waste Minimization in Metal Finishing” and the
NASA/Arkansas Space Grant Consortium through the grant
“Environmentally Benign Spray Deposition and Liquid Solution Deposition of Thin Film Coatings”. The authors also
thank Dr. Malay Mazumder of the University of Arkansas,
Little Rock for his assistance as a co-investigator on both
grants. Also thanked are Dr. Richard Kennedy and Eszter
Jakobs of the University of Arkansas for Medical Sciences
who coordinate the EPA/AR EPSCoR grant, Dr. Keith
Hudson and Lynne Tull who coordinate the NASA/AR
Space Grant Consortium, and Dr. Jerry Farris and Martha
Luster who coordinate the Arkansas State University Ph.D.
A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133
in Environmental Sciences Program with which the authors
are affiliated. The Arkansas State University College of Engineering and Dr. Albert Mink, Dr. Rick Clifft, Greg Coldwell, Susie Jacques, and Kristie Stanley are also thanked
for their day-to-day support and assistance.
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Anil Baral is a student in the Ph.D. in Environmental Sciences Program
at Arkansas State University. He obtained an MS degree in environmental
technology and management from the Asian Institute of Technology in
1997. His PhD research deals with the study of environmentally friendly
alternatives to hazardous hexavalent chromium plating and regulatory
and economic issues pertaining to those alternatives.
Robert D. Engelken has been on the engineering faculty at Arkansas State
University (ASU) since 1982, and is currently a Professor of Electrical
Engineering. He has been very active in research and development in the
field of semiconductor thin films, particularly in the fields of electrodeposition and chemical precipitation deposition of such, and his research
interests have recently broadened to include environmentally benign and
low hazard materials and material processing.