Which of the following should be stored in metal containers for safety

• A. Water
• B. Spent solvents (non-flammable)
• C. Flammable materials
• D. Non-flammable liquids

Answer: (C)

When handling flammable liquids, reducing ignition sources is crucial. Storing them in metal containers helps prevent static electricity buildup and discharges. Metal conducts electricity, and when these liquids are poured or transferred, any static charge can be quickly grounded and discharged rather than sparking. Plastic or other non-conductive containers can allow static to accumulate, increasing the risk of a spark that could ignite vapors.

Water and non-flammable liquids do not present the same ignition risk, so they can be stored in various materials that are appropriate for their use. Spent solvents that are non-flammable also do not require metal containers for safety as a general rule.

So, the safest and most appropriate choice is flammable materials.