Your iPhone can save your life. There are a number of awesome apps you can use to get yourself unstuck. The Sense+ iPhone Dock can really save your life though. It has Photo Electric smoke and gas detection sensors to detect dangerous gas and alert you and your loved ones. It sounds an alert and calls numbers of your loved ones if you are not responsive.
The Sense+ iPhone Dock should not be your only tool to avoid disaster. It does give you a better chance to become aware of dangerous gas at home. The project is being funded on Kickstarter.