Accelerat ing t he world's research. Chromium-based regulations and greening in metal finishing industries in the USA Anil Baral Environmental Science & Policy Cite this paper Downloaded from Academia.edu Get the citation in MLA, APA, or Chicago styles Related papers Download a PDF Pack of t he best relat ed papers Chromium-Based Regulat ions Applicable t o Met al Finishing Indust ries in t he Unit ed St at es: A … Pat rick St ewart Wast e Minimizat ion in Elect roplat ing Indust ries: A Review udaya bhanu Pollut ion Prevent ion & Best Management Pract ice For Met al Finishing Facilit ies Tebid Blexy 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 a 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 Abstract 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 reserved. 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 requirements. 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 carcinogenicity. 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 122 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, 1984). 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, 2000). 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 debatable. 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. 123 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, 1980). 124 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 Operation No. of plants nationwide Nationwide hexavalent chromium emissions (tons per year) Hard chromium plating Decorative chromium plating Chromic acid anodizing 1540 2790 680 161 11 3.8 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) exposure 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) 121–133 125 Table 2 Uncontrolled emission dataa from hard and decorative chromium plating Plant Process conditions No. of tanks Hard chromium plating Plant Ab 1 Plant Bb 4 Plant Cc 1 Plant Db 1 2 Plant Ed Plant Fb 3 Plant Gb 2 Plant He,f 4 Average Decorative chromium plating Plant Ig 1 Plant Jh 1 Total tank surface area (m2 ) Ah Actual gas flow rate (m3 /min) Mass emission rate (kg/hr) Total Cr Cr+6 0.08 0.011 0.026 5.2 8.5 5.8 5.6 9.2 6.7 2.5 8.5 20,458 54,667 13,983 2480 8524 8790 14,400 20,050 177 300 226 242 298 512 153 330 0.08 0.024 0.029 0.009 0.100 0.045 0.008 0.050 2.8 22.3 6500 96,840 130 990 0.0561 i e 0.102 0.045 0.0152 0.039 0.0036 0.0658 Average Process Cr+6 emissions rate (mg/Ah) 9.0 2.2 4.0 3.5 22.5 15.5 3.2 4.6 9.8 1.4 2.0 1.7 a 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). b 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 (NIOSH). 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 reduction. 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 Type 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). 126 A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133 Table 4 Standards and regulations for chromium Agency ACGIH Focus Level Comments Air–workplace 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) Urine NIOSH OSHA EPA Air–workplace Drinking water Air 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 Regulations 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, 1982). 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. 127 • 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 likely. • 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 128 A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133 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 process. • 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- 129 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, 2000). 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 4 130 A. Baral, R.D. Engelken / Environmental Science & Policy 5 (2002) 121–133 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 government. 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 sectors. 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 activities. 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 131 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. Acknowledgements 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. 132 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. References Anderson, R.A., Polansky, M.M., Bryden, N.A., et al., 1983. Effects of chromium supplementation on urinary Cr excretion of human subjects and correlation of Cr excretion with selected chemical parameters. J. Nutr. 3, 276–281. Agency for Toxic Substances and Disease Registry (ATSDR), 1993. Chromium. 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In: Proceedings of the Presentation at the 27th Aerospace/Airline Plating and Metal Finishing Forum, San Antonio, March 1991. Talaat El-Mallah, A., et al., 1993. Autocatalytic (electroless) deposition of nickel–phosphorous–born alloys. Part III. Deposit properties. Met. Finish. 98 (8), 23–28. World Health Organization (WHO), 1988. Chromium. Environmental Health Criteria 61, Geneva, Switzerland. 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.