Residents of a Chicago neighborhood near a large natural gas pipeline claim they had no idea the pipeline existed, and there are no signs there to indicate a major pipeline there. Utilities are required by law to mark pipelines clearly and notify residents about the oil and gas lines running beneath them.
ABC News talked to Consolidated Edison, the utility company in the New York City area, about the top signs of a natural gas leak. Here are some things to look for to keep you and your family safe.
Smell: Natural gas is colorless and odorless but utility companies often add an odor to the gas so that leaks can be detected. At the start of heating season, some utility companies will send scratch-and-sniff samples so that you know what to look for. Typically, it's a rotten egg smell.
Hear: If you hear a roaring, hissing or whistling sound, it could be a leak.
See: Look for a white cloud or a misty fog. If you notice bubbles in standing water or vegetation that appears dead or seems to be dying for no reason, there might be a natural gas leak.
If you do suspect a leak, you should leave your house immediately. Open your windows if there is a faint odor. Don't do anything that could create a spark, meaning don't turn on and off your lights or appliances or use your telephone or cell phone. Ringing a doorbell or even starting your car could create a spark.
ABC News' Neal Karlinsky, Barbara Pinto contributed to this report.