Consider the following statements :
1. CO₂ should be used to control 'B' type fire
2. Special dry chemicals can be used to control 'B' type fire
3. Foam extinguishers are less effective to control 'B' type fire
4. Steam of water should be used with caution as it may spread the 'B' type fire
Which of the statements given above are not correct ?

This question is from the UPSC CISF AC (Exe) LDCE 2023 exam. According to the official answer key, the correct option is D, meaning all four statements are considered correct (true).

• Statement 1: CO₂ is a standard extinguishing agent for Class B fires (flammable liquids) as it smothers the fire by displacing oxygen.
• Statement 2: Special dry chemicals (like BC or ABC powder) are highly effective for Class B fires due to their rapid knock-down effect.
• Statement 3: While foam is effective for blanketing, it is often considered less effective than dry chemical powders for rapid suppression of certain liquid fires, particularly running or pressurized fires.
• Statement 4: Water should be used with extreme caution; a stream of water can cause splashing, while the rapid conversion of water to steam can cause a "slop-over" or "boil-over" effect, spreading the fire.

Since all statements are technically true in a professional fire-fighting context, none of them are "not correct".