Which category is associated with a 25-gallon quantity in flammable storage?

• A. Class 1A
• B. Category 1/2/3
• C. Category 4
• D. Class 1B

Answer: (A)

Understanding how flammable liquids are stored relies on both the liquid’s properties and how much is being kept on site. When the quantity is around 25 gallons, the storage category used for Class I flammable liquids is Class 1A. This designation signals the most restrictive level within the Class I group, reflecting the higher risk due to very low flash points and boiling points. With this category, you apply stricter controls, such as a listed flammable-storage cabinet, proper ventilation, grounding of containers, and adequate separation from ignition sources. The other category schemes you might see describe different organizational approaches, but for a 25-gallon storage scenario, Class 1A is the applicable category and guides the required safeguards.