Green chemistry is a newer way of looking at the chemicals and the way these chemicals are used on the job site. The working definition of green chemistry is “the invention, design and application of chemical products and processes to reduce or to eliminate the use and generation of hazardous substances.” Green chemistry was first developed by the Environmental Protection Agency in reaction to the Pollution Prevention Act of 1990. This act established a national policy to prevent or reduce pollution at its source whenever possible and to devise creative strategies to protect human health and the environment. The original program provided grants for research projects that worked on these topics.
In 1993 the program was broadened to include more topics like greener solvents and safer chemical alternatives. The program was then renamed “Green Chemistry.” The Green Chemistry Program has brought about cooperation between academia, industry, government agencies and non-government organizations to promote the use of chemistry to prevent pollution through completely voluntary non-regulatory partnerships.
The concept of Green Chemistry is based on 12 principles developed by Paul Anastas and John C. Warner at the EPA. These principles serve to explain what the definition of green chemistry means in practice. The 12 principles are as follows:
1. Prevent waste by designing ways to use chemicals to prevent waste. No waste means no need to treat or clean up.
2. Design safer chemicals and products. Ideally these products would be fully effective and have little or no toxicity.
3. Design less hazardous chemical processes. Design means to use substances that use and produce chemicals with little or no toxicity to humans and the environment.
4. Use renewable resources. Use raw materials and resources that are renewable rather than depleting. Renewable resources will often come from agricultural products or perhaps are waste products from other processes. Depleting resources are those whose source can be used up, for example fossil fuels.
5. Use catalysts to complete chemical reactions. Waste can be minimized by using catalysts or chemicals that are used in small amounts and can be used many times without being used up. Other types of reagents work in only one chemical reaction.
6. Avoid chemical derivatives. By keeping a chemical reaction as simple and straightforward as possible, the amount of waste generated can be minimized.
7. Maximize chemical economy. Using chemical reactions in which the final product contains the greatest amount of the starting materials will decrease the amount of chemicals wasted in the process.
8. Use safer solvents and reaction conditions. The use of solvents, separation agents or other extra chemicals should be avoided. If they must be used, the safest chemicals should be chosen.
9. Increase energy efficiency. Chemical reactions should be run at room temperature and pressure, when possible.
10. Design chemicals and products to degrade after use. Chemicals that are designed to break down to harmless substances after use will prevent harmful chemicals from building up in the environment.
11. Analyze in real time to prevent pollution. Real-time monitoring and control of chemical reactions can minimize or eliminate the formation of byproducts that must be disposed of later.
12. Minimize the potential for accidents. Design chemicals and the form they take (solid, liquid, gas) to minimize the potential for chemical accidents like fires, explosions and releases to the environment.
The point of these principles is to indicate areas that need attention when making and using chemicals in the workplace. The principles help to illustrate that green chemistry isn’t a particular set of technologies but an emphasis on the design of chemical products and processes. The bottom line of all this is to help reduce the risk of chemicals and chemical processes on humans and their environment. It should be stressed that green chemistry, as stated in the principles, looks at the hazards of the chemical process as a whole not just any undesirable substances that may be inadvertently produced in their use.
Two terms are used repeatedly in the discussion of green chemistry: risk and hazard. These terms are inextricably tied to one another. It is often said that risk is the product of hazard and exposure. Most times when looking to reduce the risk of an occurrence, the most direct way to do this is by reducing the exposure to the threat. This is also true for chemistry and the use of chemicals on the job site. Regulations often require increases in control and treatment technologies and in personal protective equipment like respirators and gloves to reduce the risk by limiting exposure.
While PPE can be very effective in reducing an employee’s risk, there is always the concern about the cost of PPE and the potential for failure of equipment or it being used incorrectly or not at all. Green chemistry tries to reduce risk by reducing the hazard associated with the use of chemicals. It’s a way of dealing with risk reduction by decreasing the intrinsic hazards of the substances that are used at a job site; there is no need to worry about exposure if the chemicals that are being used don’t have any hazards associated with them.
The bottom line of green chemistry is that its use can help protect many aspects of a company’s life. The employees using the green chemicals are safer and potentially healthier while making the planet a safer place to live and reducing the impact on generations to come.
Diane Kelly is a safety specialist with INTEC, Waverly, Pa.
