Overview
- Inorganic acids
- Organic acids
- Bases
- Oxidizers
- Organic peroxides
- Strong reducing agents
- Everything else
Incompatible chemicals must be physically segregated. Sometimes this is accomplished by distance. Other times it is accomplished by utilizing containment trays, as shown in the picture shown here. Compatibility guidance is generally based on grouping of chemicals by physical attributes. A common grouping scheme is listed above.
These groupings don’t necessarily follow the GHS hazard classification scheme, DOT hazard classification matrix, or other similar system. So, don’t rely on those classifications. When evaluating this checklist item, use the general chemical grouping as an “indicator” of a potential incompatibility, but only cite this checklist item if there is an actual incompatibility between two or more chemicals present. For example, fuming nitric acid is an inorganic oxidizing acid. Hydrochloric acid is a non-oxidizing acid. These two materials from different classes could be stored together since they are unlikely to have a significant chemical reaction if combined. On the other hand, acetic acid is an organic acid. It should not be stored with nitric acid because of the fire potential when mixing organics and inorganics. You may have to do a bit of homework to determine if there is a compatibility issue by consulting the SDSs of chemicals stored together that are of differing compatibility groupings and/or consulting a Senior Specialist.
Please note: It is also very important to recognize that this addresses incompatible storage only. Some organic acids and bases are also flammable and need to be in a flammable liquid's storage cabinet. Some chemicals in the ‘everything else’ category require special storage. For example, some organic peroxides need refrigeration to remain stable.
Another helpful tool is the DOT list of Self Reactives and Organic Peroxides provided here as PDFs.
Another consideration is the compatibility of the chemical with the storage container and the material of construction of the storage location or secondary containment device. For example, glass is a poor container choice for hydrofluoric acid - it will eat right through the container. Metal containers and unpainted metal storage shelves are a bad choice for corrosives- they will eat through the metal. Wood and paper-based storage systems are bad choices for oxidizers- mixing of the two under the right conditions results in a fire.
Citations and Related Resources