- Introduction
- What are Waste Minimization and Pollution Prevention?
- Why are Waste Minimization and Pollution Prevention Important?
- Purchasing Chemicals
- »Managing Chemical Inventories«
- Dealing with an Existing Inventory of Unwanted Chemicals
- Conducting Experiments
- Scaling Down Experiments
- Substituting Materials
- Alternatives to Wet Chemistry
- Reusing and Recycling Chemical Resources
- Segregating Waste Streams
- In-Laboratory Treatment of Wastes
- Working with School Administrators, Students, Other Schools, and the Community
- Getting More Information
- Appendix A—Waste Minimization Checklist
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Managing chemical inventories effectively can prevent many of the ills that plague environmental managers: unknown chemicals, excessive inventory stocks, and poor use of materials. By managing chemical inventories in a few simple but effective ways, you can avoid many of these problems.
Label chemicals properly
Proper labeling is a simple and powerful way to reduce many of the environmental hazards and costs associated with chemicals used in the laboratory. Since chemistry teachers and students are responsible for producing chemicals wastes, they should shoulder the responsibility for identifying the wastes. Mixing unknown or improperly identified wastes can produce dangerous reactions; people have been injured and killed at waste treatment facilities because wastes were poorly identified and packaged.
Consider also the costs of mislabeled or unidentified chemicals on your shelf: the cost of analyzing a chemical prior to disposal can exceed $1,000, by one estimate, many times the original cost of the product. Properly labeling containers also decreases the risk of accidents and injuries, and aids in complying with regulatory requirements such as hazard communication to the local fire department.
Some recommendations for labeling are:
- Establish a policy that requires identifying all chemical containers—including waste containers—and specifying a responsible party.
- Adopt a standard labeling procedure for chemicals and wastes.
- Use labels that are colorfast and permanent.
- Some (larger) laboratories use tags for waste containers, or Universal Product Code (UPC) systems with a bar code scanner; facilitate computer tracking of the chemical by name, formula, and location and responsible person.
Store chemicals in a centralized place
Laboratories often use a wide variety of toxic, corrosive, reactive and flammable chemicals in small containers. These chemicals should all be stored in a designated, centralized place. Even a small middle school chemistry program should establish a designated chemical storage area. Some recommendations for proper storage include:
- Store chemicals in such a way as to reduce the risks of breakage and spills that could release materials into the environment. For example, glass containers should always have secondary containment in case of breakage.
- Store incompatible materials separately (e.g., keep flammables in a separate cabinet, away from oxidizers, acids from bases). In general, organize your storage to keep like chemicals together and to follow a systematic order. Using a systematic order for storing your chemicals will not only help avoid accidents, it will make retrieval easier. The 5 main chemical classes to segregate:
- oxidizers
- corrosives
- flammables
- toxins
- reactives
- Store chemicals at the correct temperature, which should be clearly displayed on the container label.
- Anchor storage cabinets to walls and floors as needed to so that earthquakes and other hazards cannot topple cabinets.
- Record any spills or leaks and have a plan to respond to them.
- Periodically inspect stored chemicals for signs of leakage, poor storage practices, or any other problems.
- Spill and leak protection should be available in chemical storerooms. Berms, sumps, or even simple plastic bins can be useful forms of protection. If necessary, showers, sinks, absorbent materials, and other sanitary and safety equipment should be readily available for cleaning up a spill.
Track chemicals from “cradle to grave”
An effective chemical tracking system and inventory control is essential to waste minimization. For instance, by tracking chemical purchases and shelf life, you can identify how frequently materials are used, dispose of chemicals as shelf life expires, identify chemicals for exchange with other schools, reduce quantities purchased so that chemicals are completely used before their shelf life expires, and minimize needless waste.
The chemical tracking system should be designed to track chemicals from the time they are purchased through the time when they are used, and ultimately disposed. A tracking system should provide information on who uses chemicals and where chemicals are kept. The “cradle-to-grave” tracking system you develop will depend on the resources you have at your disposal to revise your current inventory control, the demands on your chemical inventory, and the scale of your laboratory operations. A good chemical inventory system will provide the chemicals needed in the right amount with a minimum hassle, and maximize efficient chemical use and distribution.
A cradle-to-grave tracking system includes a centralized inventory space, a file or data management system, and a person assigned to overseeing chemical inventory control and distribution. The inventory control system can be relatively straightforward or very complex, using the latest inventory management methods. Very easy to use inventory systems are available from such vendors as Baker Chem, Flinn, and the American Chemical Society for about $125. Alternatively, many off-the-shelf software packages such as Excel, Lotus 1-2-3, or FoxPro can be used to track chemical inventories. Some options for an inventory system include:
- Link purchasing request into the inventory system so that excess chemicals in stock can be used before buying more, or ensure that purchasers regularly check the inventory to avoid overstocking chemicals.
- If materials are not centralized, conduct a school-wide inventory to identify where chemicals are located to facilitate sharing, and identify expired chemicals that should be disposed of. Provide a simple monthly listing to chemical users on available chemical stocks, location, and points-of-contact.
- Date chemical purchases and rotate chemical stocks using a “first in, first out” rotation; in other words, use the oldest chemicals first.
- Conduct regularly scheduled inventory audits to identify chemicals that aren’t being used, and feed this information back to procurement to cut down on excess inventory going to waste.
- Regularly “purge” chemicals that are no longer used, if possible, and list them with the local hazardous waste exchange. Also, return expired materials to the supplier, if possible.
Storing waste prior to disposal
Storing wastes should follow many of the same practices used for storing virgin chemicals. That is, wastes should be clearly labeled, they should be grouped and segregated according to type, and they should be tracked. Here are some general suggestions for how to store waste, whether or not it is legally considered hazardous:
- If you know that the waste is hazardous, label the waste with the words “Hazardous Waste,” the date, and the type of hazard of the material (corrosive, explosive, etc.). Otherwise, label your waste with the words “Potentially Hazardous Waste,” the date, and the type of hazard. A waste label should provide as much information as possible. The waste should be identifiable as a specific compound.
- As with all chemical storage containers, make sure the waste storage container is compatible with its contents. Keep it tightly closed.
- Segregate all wastes based on chemical incompatibilites.
- Store so you can inspect it all (e.g., don’t pile containers on top of each other).
- Inspect the waste regularly for damage to containers or leaks.
- Make sure that any people handling the waste are familiar with the hazards associated with it, as well as with the regulations governing waste handling and storage.
Finally, keep in mind that storing waste isn’t the end of the story—you need to have a plan in place for disposing of the waste. Even small chemistry programs are limited in the amount of hazardous waste they can accumulate on-site at any one time. Under federal law, if you accumulate over 1000 kg of hazardous waste, you will be subject to considerable regulation; state and local laws may impose lower limits than federal regulations.
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