Old, expired and legacy chemicals that are stored for many years can introduce more hazards into the laboratory when compared to the original chemical.

Legacy chemicals are often inherited chemical stocks from previous occupants or team members. Often, these chemicals are left in the back of cabinets, desiccators or drawers for many years, unnoticed and unused. It is not unusual for these chemicals to be grouped based upon the name(s) of the previous owner(s), and as a result, are sometimes stored with incompatible chemicals. In addition to taking up valuable space, some of these chemicals can become dangerous as they age. Small leaks that go unnoticed could cause violent reactions and generate toxic fumes.

Below is a list of some chemicals that pose serious hazards when stored for an extended period of time:

• Picric acid (solid or as part of a premade stain or solution): Pure picric acid is a shock-sensitive explosive. For that reason it is shipped wet (or in solution) and it should be checked for its water content quarterly. Do NOT open a bottle of it that appears to be dry or has not been checked for a long time; immediately notify VCU Environmental Health and Safety at (804) 828-9834.
• Perchloric acid: While 70% perchloric acid is stable, many of its salts (perchlorates) are shock-sensitive explosives. Old perchloric acid bottles may have formed crystals that are explosive.
• Hydrofluoric acid: Hydrofluoric acid (HF) is stored in plastic bottles, which deteriorates with time and becomes brittle. There have been cases where bottles have broken when picked up. HF is highly toxic; a minor exposure can have serious consequences.
• Diethyl ether (or short ethyl ether): Diethyl ether forms explosive peroxides over time. Bottles should be dated upon receipt and checked for peroxide regularly. Old bottles that have not been checked may contain significant amounts of peroxides. Other commonly found peroxide formers are isopropanol (2-propanol), isoamyl alcohol, tetrahydrofuran and dioxane.
• Hydrazine and other corrosives: These materials can cause container lids to corrode and leak causing a leak that allows toxic vapors to escape.

Other chemicals may not become more hazardous as they age, but they degrade, rendering them useless.

Disposal of chemicals

All laboratory groups are strongly encouraged to dispose of old and expired chemicals as well as any chemicals not in use.  There is no charge for disposal; however, labs can be held responsible for property damage that occurs due to unmanaged legacy chemical stocks, cleanups or larger bulk disposals. Information for hazardous chemical pick-ups can be found here.