What Are the Signs of a Gas Leak?

Watch for smell, sound and sight. The US Pipeline and Hazardous Materials Safety Administration says gas distribution systems are odorized with the chemical mercaptan or similar chemicals, that a leak can sound like anything from a quiet hissing to a loud roar depending on its size, and that dead or discolored plants in an otherwise healthy area, or frozen ground in warm weather, are other possible signs.

If you suspect a leak, the agency says to leave the area on foot immediately without trying to locate the source, direct others to leave, try to stay upwind, and call 911 from a safe location before notifying the pipeline company. It says not to create any open flame or other ignition source such as an electrical switch or vehicle ignition, not to start motor vehicles or electrical equipment, and not to use a telephone or cell phone.

Carbon monoxide is a separate danger. The CDC says the most common symptoms of carbon monoxide poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion, and that they are often described as flu-like.

Sources checked September 15, 2026. Every point below links the page it came from.

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Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.

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