What should be done first if a leak occurs?

In the event of a gas leak, the priority response is to ensure the safety of those in the vicinity. Turning off the gas flow is a critical first step because it helps to prevent any further accumulation of gas that could lead to an explosion or fire. By shutting off the gas, you are directly mitigating a hazardous situation and reducing the risk to people nearby.

Once the gas flow is shut off, the next steps typically involve notifying emergency services and evacuating the area as needed. These actions are crucial for ensuring the safety of individuals in the vicinity, but the immediate action of stopping the gas supply is essential for preventing further danger. Sealing the leak is also important but should not be attempted until it is safe to do so, which is why the priority is to turn off the gas first.