II. R&D NEEDS AND POTENTIAL PROJECTS

A. Cadmium

1. Background

Cadmium is used in the metal plating industry as a sacrificial coating on steel parts. Because cadmium is less electrochemically active than zinc or aluminum, it is frequently used on high-strength steel parts that might be embrittled by more active, sacrificial corrosion reactions. Although a useful industrial metal, in 1992, the Occupational Safety and Health Administration (OSHA) revised the permissible exposure limit (PEL) for cadmium in the workplace. The new OSHA PEL was 95% lower than the previously acceptable value. This reduction along with other factors such as labeling requirements under OSHA, a ban on cadmium coated parts in Europe, and strict regulation of cadmium in wastewater discharges have led many companies to opt to eliminate or replace cadmium plating operations.

The Environmental Protection Agency has also developed new standards for cadmium emissions in industrial wastewater. These new standards will impact metal finishing operations included in the Metal Products and Machinery (MP&M) industry categories. However, the EPA MP&M proposal does not include significant reductions in allowable cadmium emissions. Thus, most cadmium elimination projects are motivated by the OSHA regulations and not by EPA action.

2. Federal Survey

The Federal survey revealed a number of projects and resources devoted to finding alternatives to cadmium plating and improving operation of existing cadmium plating and stripping operations. Approximate resources devoted to these topics over the last several years totaled over $3.3M with most ($2.8M) going to development and demonstration of substitutes; the remaining $0.5M went to reducing cadmium loss through cadmium recovery. Except for two $50K studies by EPA, one which looked at ion exchange cadmium recovery and another which looked at a zinc substitute, the projects were DOD-funded. The approximate $3.2M in DOD funding supported projects to develop and demonstrate zinc-based alternatives and lubricants and dry application processes, such as ion vapor deposition.

No other sources, aside from Federal, were identified as involved with cadmium research. It is probable that the private sector, especially chemical suppliers, are active in this area. However, further investigation would be necessary to estimate the funding levels and specific emphases.

3. Projects

The following are possible R&D projects:

a. Develop a Life Cycle Cost Model that could predict when it would make sense to replace cadmium and when it would make sense to continue using the metal. The basic idea is that it may not represent "common sense" to categorically replace the use of this metal coating.


i. Determine actual airborne cadmium concentrations from plating operations. Answer the question, "When in the finishing industry is cadmium use likely to cause worker health and environmental problems?"

ii. Evaluate the effectiveness of simple techniques such as ventilation, tank covers, floating balls, etc., to reduce airborne cadmium levels. Answer the question, "Can simple techniques reduce airborne cadmium levels to below the OSHA PEL?"

iii. Generate a cost model that reflects both the risks and the control technologies. The cost model should be developed to allow analysis of life-cycle environmental expenses and expenses associated with re-engineering components that are currently cadmium plated. The model should address both the OSHA and the EPA issues and should include analyses of both current and proposed regulations. EPA staff participating in the process should ensure that solid waste, air, and water issues are considered. The final product should be a simple-to-use document or Internet program that demonstrates to the user community when "common sense" shows that cadmium should, and should not, be replaced.


b. Develop technologies that might reduce cadmium air emissions and associated worker health problems. Technologies that reduce water pollution and solid waste generation should also be considered.


i. Develop new tank covers to allow recovery of metal that would normally be lost in tank mists.

ii. Develop improved (possibly computer-controlled) power sources that would minimize hydrogen generation and improve metal deposition rates.


c. Publicize already completed cadmium replacement research. Use a literature search to produce guidance (perhaps as an article in a journal) for when and how industries should replace cadmium coatings. The article should include successes, failures, and points-of-contact for additional information.

d. Develop and demonstrate alternatives to cadmium used on aluminum materials and electrical connectors.

e. Demonstrate cadmium alternatives such as Boeing's zinc nickel and another which is based on combining zinc, black passivation, and organic top coating.