What is the minimum withdrawal distance for HD 1.4 explosives?

• A. 100
• B. 250
• C. 300
• D. 500

Answer: (C)

Withdrawal distance is the minimum safe space needed between personnel and explosive items to prevent injury from blast effects, fragmentation, or heat if something goes wrong. For HD 1.4 explosives, the standard minimum withdrawal distance is 300 meters. This distance accounts for potential blast overpressure and fragment travel, even though HD 1.4 items are lower hazard than the most energetic classes. The choices of 100 and 250 meters are too short to reliably protect against those effects, while 500 meters is more conservative than typical requirements for this classification. Always follow site-specific safety protocols, but 300 meters is the established minimum for HD 1.4.