A gas leak happens when gas that is meant to stay in pipes or tanks gets out into places where it shouldn't be, like in the air where you can breathe it. Gas is not something we can see, so we use special tools and sensors to tell if there is a gas leak. If someone smells a funny, rotten egg-like smell or if they hear a hissing sound that isn't normally there, they should tell an adult right away. Gas leaks can be dangerous because gas can make it hard to breathe and it can catch fire or explode. So it's very important to stay away from the area where the gas leak is and let the grown-ups handle it. They'll call special helpers called "emergency responders" who will fix the gas leak and make everything safe again.