Petroleum products, such as grease or lubricating oil, may burn easily in the presence of oxygen.

• A. True
• B. False
• C. Depends on conditions
• D. Never

Answer: (A)

Flammability comes from the fuel’s ability to form vapors that can react with oxygen in the air. Petroleum products like grease and lubricating oil are hydrocarbon fuels; they release vapors that mix with the surrounding air. When those vapors reach an ignition source or enough heat, they ignite, and the flame is sustained by the oxygen in the air. Even if the liquids themselves don’t ignite at room temperature, their vapors can, and once ignition occurs, combustion proceeds readily. So, in the presence of oxygen, these petroleum products may burn easily. The statement isn’t about a fixed fact under all conditions—the general hazard is real because air provides the necessary oxidizer and vapors can form an ignitable mixture.