The gas mask was patented in 1849, but was not widely used until World War I (1914), to protect our doughboys from harmful fumes ?over there.? But some gas fumes are meant to be sniffed, such as the gas used for home heating and cooking. In its natural state, gas is clear and odorless, making it hard to detect and extremely dangerous. That's why the gas piped into your home has a special heavy odor added. It's so you can detect even small amounts of gas escaping. When you smell gas, it's serious business. Turn off any flames, then open windows and doors, and get out as quickly as possible. Don't turn on light switches or use the phone to call the gas company; even the tiniest spark can cause a massive explosion. Once you're outside, close the main shut-off valve and use a neighbor's phone to report the problem. Remember: the smell of gas is there for a reason. Never ignore it, no matter how minor it might seem. For more tips, visit our Web site at onthehouse.com. And that's the On The House tip for today.