Colorless

Natural gas is completely clear; you cannot see it.  Therefore, it's important to know how to recognize a leak.  Before natural gas is delivered to your home, an odorant that smells like rotten egss is added to you can recognize a leak.  Other indications that a leak has occurred is a hissing or leaking sound, blowing dust, dead vegetation in a normally green area, or continuous bubbles in an underwater area.