Proper labeling of all chemical containers by lab members will prevent the creation of dangerous, expensive-to-dispose chemical wastes of unknown origin. Workers who generate large amounts of small sample-sized containers of waste must be equally careful to positively identify all chemical constituents in their samples so that they may be properly managed and disposed of.
Before leaving a lab, workers must ensure that all chemical wastes that they have been responsible for creating are positively identified and labelled.
Hazardous waste labels should be affixed to waste containers before any waste is added to the container; a running list of constituents can then be easily completed and tracked by all members in the lab. Each time a new constituent is added, the new addition must be added immediately to the label.
If lab workers come across old or abandoned chemicals of unknown origin or make-up, they are directed to label the container with a Hazardous Waste label, and write “UNKNOWN-100%” in the constituent section. Dispose of the unknown waste through EH&S as soon as possible to prevent an inadvertent personnel exposure to the unknown chemical.