When a gas distribution system has burning gas, which action aligns with recommended practice?

• A. Extinguish the flame immediately
• B. Isolate the gas source and let flame continue
• C. Vent the area aggressively with water
• D. Apply foam directly to flame

Answer: (B)

When a gas distribution system has a flame, the first priority is to stop the fuel from continuing to flow. Isolating the gas source prevents more gas from reaching the flame, which reduces the risk of a larger, more dangerous release or explosion. If the gas supply is shut off, the existing gas in the area can burn off safely at the flame, provided there are no other ignition sources and the scene is secured. Extinguishing the flame without cutting off the gas just allows fuel to keep flowing, making re‑ignition or spread more likely. Water or foam isn’t the proper approach for a gas leak fire, as these methods don’t reliably stop the gas and can introduce additional hazards. So the recommended action is to isolate the gas source and let the flame burn off the gas already escaped.