Waste Not, Want Not
Roy, Ken, The Science Teacher
March 2013, Best Practices for Safety Issues in the Science Classroom and Laboratory
After each lab experiment, chemistry students dumped chemical products into plastic-lined trash containers. Problem was, another class used the lab--and dumped different chemicals in the pails. One day the garbage pail started to smoke. Then a flame erupted. The teacher put it out with an extinguisher, but soon another pail started smoking. The teacher evacuated the lab and put out the second fire as well. Mixing chemical product residue almost caused a serious incident. How could this have been avoided?
Planning for safer waste disposal
With microchemistry and other waste-reducing alternatives available, only small amounts of hazardous waste should be produced. Use only chemicals appropriate for high school (see "On the web") and properly dispose of any solid or liquid wastes produced. Follow these procedures:
Proper receptacles: Use enough waste containers to prevent cross contamination. They should be big enough for the number of students and labs run. In most cases, use one-or two-liter plastic, lidded containers made of high-density polyethylene and rated as "chemical resistant." Label and color-code the containers for either liquid or solid chemical waste. After the lab, remove the containers from the room.
Tag it: Label each container with the chemical waste components, known hazards (e.g., GHS [Globally Harmonized System for the Classification and Labeling of Chemicals] pictograms), date, school building, lab number, and teacher.
Storing waste: If more waste is to be added to a container, segregate containers into compatibility groups and mark the additional contents on the tag. Keep containers closed while stored and segregated from other chemicals. Have the appropriate Material Safety Data Sheets (MSDS) or Safety Data Sheets (SDS) available.
Removing waste: The process depends on what type of waste. Some forms can be processed onsite. Others must be removed from the site responsibly. (Create a manifest for the removal process. …