Overview
Chemicals that may become hazardous upon prolonged storage are not dated, have not been tested at the appropriate interval, or have been stored for an excessive period of time.
- Peroxide formers
- Picric acid
- Gases
- HF and HBr
- Acid & alkali gases
- Gases subject to autopolymerization
- Gases subject to explosive decomposition
The most commonly encountered materials in a laboratory that can become hazardous upon prolonged storage are certain organic solvents, such as ethyl ether, 1,3-dioxane, 1,4-dioxane, tetrahydrofuran, and acetaldehyde. Refer to the EHS SOP, Use and Storage of Peroxide-Forming Chemicals for more information and a list of chemicals prone to peroxide formation. Look to see that peroxide forming chemicals are clearly labeled with a date (preferably the date received, and date opened, although in the absence of each a manufacturer’s date may be used if available), a warning statement, and that they are not stored for an extended period of time.
In the case of solvents, the general recommendation is that the solvent is tested or disposed no longer than one year from the date that the container was opened, and preferably at 6-month intervals.
Picric acid (trinitrophenol) is very sensitive to shock, friction, and other initiating sources. It is shipped in a wetted state to minimize its sensitivity. When stored over time, it can dry out and simply opening the cap can initiate an explosion.
Cylinders of hydrogen fluoride and hydrogen bromide should be returned to the supplier within 2 years of the shipping date. Cylinders of corrosive or unstable gases should be returned to the supplier when the expiration date of the maximum recommended retention period has been reached. In the absence of a maximum recommended retention time, a 36-month interval should be used. One gas that can auto-polymerize is 1,3-butadiene. One that can explode if over pressurized is acetylene.