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If you smell a rotten-egg or sulfur odor, hear hissing, whistling or roaring, or see blowing dirt, bubbling water or dead vegetation, treat it as a possible natural-gas leak. Warn others only if you can do so without delay, leave immediately on foot, move away from the suspected leak and get upwind when practical.
From a safe location, call 911 when there is immediate danger and notify the local gas utility or pipeline operator. Do not use phones, switches, vehicles, flames or appliances in the suspected gas area, and do not return until emergency responders or utility personnel say it is safe.
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What to do first when you smell gas
Evacuation is the first priority. Do not stay inside to identify the source, open every window, shut a valve or collect belongings. Take everyone and pets with you if they are immediately reachable, but do not delay your exit to search rooms or basements.
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- Warn people as you leave. Use your voice if others are nearby and warning them does not slow your escape.
- Leave on foot. Do not start a car, use a garage-door opener or drive a vehicle through the suspected gas area.
- Move away from the odor or other signs. Get upwind when practical. There is no single safe distance that applies to every leak; the amount of gas, wind, terrain, building layout and whether a pipeline is damaged all affect the hazard.
- Call from safety. Use a phone only after you are well away from the suspected leak. Call 911 for immediate danger and contact the local gas utility or pipeline operator.
- Keep others out. Do not let anyone re-enter to retrieve items, investigate or relight equipment.
The Pipeline and Hazardous Materials Safety Administration summarizes the immediate instruction as: “Leave the area.” The American Public Gas Association likewise advises finding a phone away from the area to call 911 and the natural-gas utility.
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- 85-decibel alarm announces when carbon monoxide or explosive gas is detected
- Peak Level Memory records the last time carbon monoxide was detected or when the unit was last tested
Warning signs of a natural-gas leak
Natural gas is naturally colorless and odorless. Utilities add an odorant commonly described as sulfur or rotten eggs, but odor is not guaranteed: some people have a reduced sense of smell, odors can be masked, and a leak may be noticed first through sound or visible changes.
Odor
A strong or spreading rotten-egg or sulfur smell indoors or outdoors should be treated as a possible leak. Do not assume the odor is harmless because it is faint, intermittent or limited to one room.
Sound
Hissing, whistling or roaring near an appliance, meter, service line or pipeline can indicate escaping gas. You do not need to locate the exact point before leaving.
Visible outdoor clues
Blowing dirt or dust, bubbles in standing water, and unexplained dead or dying vegetation near a line can signal escaping gas. These signs require the same response as an odor: leave the area and report it from safety.
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Actions that can ignite accumulated gas
A gas-air mixture can ignite from a flame, an electrical contact or static discharge. In the suspected gas area, avoid all of the following:
- Turning lights, switches or other electrical controls on or off.
- Using a phone, flashlight, computer, appliance, doorbell or electrical outlet.
- Operating a garage-door opener or other powered equipment.
- Starting an engine or moving a vehicle through the odor area.
- Lighting a match, lighter, candle or cigarette.
- Touching equipment unnecessarily, including a gas meter or shutoff valve.
- Attempting to close valves, repair a line or investigate with tools.
Make every call only after reaching a safe location. Do not go back inside for a phone or flashlight. The safest response is to remove people from the hazard and let trained responders control ignition sources and gas service.
Should you open windows or ventilate?
Evacuate before thinking about ventilation. Official guidance is not completely uniform: some utility instructions say an exit door may be left open while you leave, or that windows may be opened only if doing so is quick and requires no additional controls. Other regulator guidance warns that operating a window, switch or fixture can create an ignition source.
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- Do not remain inside to open windows.
- Do not run a fan, HVAC system or other appliance to disperse gas.
- Do not touch switches, plugs, thermostats or window hardware if doing so could delay departure or create an electrical contact.
- If an exit door is already being used and can remain open without stopping or manipulating controls, leaving it open may be consistent with some utility guidance; never delay evacuation to do this.
Ventilation is secondary to getting out. Fire officials, emergency responders or the utility will determine when the area can be ventilated, entered and returned to service.
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When to call 911 and when to call the gas utility
Call from a safe location, never from inside the building or beside the odor. You may need to notify both agencies; they perform different roles.
| Situation | Who to call | Information to provide |
|---|---|---|
| Immediate danger, strong or spreading odor, fire, explosion risk, injuries or a damaged pipeline | 911 first, then the gas utility or pipeline operator if emergency personnel direct you or if the utility has not been notified | Exact location, whether anyone is injured or trapped, what you smelled, heard or saw, and whether flames or damage are present |
| Suspected leak without an obvious fire or injury | Local gas utility or pipeline operator from safety; call 911 if conditions worsen or there is any immediate threat | Address or nearby landmark, odor location, hissing or visual signs, and whether the building has been evacuated |
| Outdoor pipeline or service-line damage | 911 and the pipeline operator or local gas utility | Road, property or landmark, visible damage, blowing dirt or bubbling water, and your safe location |
Utilities dispatch trained personnel to investigate and control gas service. Follow the dispatcher’s instructions, keep your distance and do not approach crews or equipment until they tell you it is safe.
How far away should you go?
No universal number of feet is established for every natural-gas leak. Move far enough away that you are no longer in the odor or visible hazard area, and position yourself upwind when practical. If the leak is near a building, meter or pipeline, increase your separation rather than waiting nearby for responders.
Do not gather at the doorway, beside the meter, in a driveway where a vehicle could start, or near a suspected underground line. Stay at your safe location while making calls and keep children, pets and bystanders away. Emergency responders or utility personnel can establish a safe perimeter and tell you where to remain.
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Can you turn off the gas yourself?
Do not operate a gas valve, meter or appliance control when you suspect a leak. Reaching the valve may take you into the gas cloud, and manipulating equipment can create an ignition source or interfere with the utility’s response. Do not attempt a repair, disconnect an appliance or relight a pilot.
Leave the control of gas service to the utility or emergency responders. If they shut off service, do not restore it yourself. A qualified professional must determine whether appliances, piping and regulators are safe before service is returned.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.When is it safe to return or relight appliances?
Do not re-enter, relight appliances or restore gas service because the odor has faded. Odor can be absent or difficult to detect even when a hazard remains. Return only after fire officials, emergency responders or utility personnel explicitly declare the area safe.
Once officials allow re-entry, follow their instructions about appliance operation, inspections and any required repairs. If an appliance was affected, leave it off until the utility or a qualified professional says it can be used. Never bypass a shutoff, defeat a safety device or make an improvised repair.
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Will a natural-gas detector warn you?
A residential natural-gas detector or alarm can provide an additional warning, particularly for someone who may not reliably smell the odorant. The American Public Gas Association notes that detectors are sold through hardware stores and online. The District of Columbia Public Service Commission stresses that a detector is a backup device, not a replacement for evacuation and professional help.
When choosing an alarm, verify the following in the current product documentation and local requirements:
| What to check | Why it matters |
|---|---|
| Sensing technology and the gas type listed | Make sure the device is intended to detect natural gas or methane, rather than a different hazard such as carbon monoxide or smoke. |
| Alarm audibility and visual indicators | A loud alarm and visible status or warning indicators help occupants notice an event in different rooms or conditions. |
| Power source and backup | Check whether it uses mains power, batteries or both, and how it signals low power. |
| Installation placement | Follow the manufacturer’s placement instructions for the gas type and building layout; do not improvise a location. |
| Certification or listing | Look for recognized safety certification or listing appropriate to the intended use and jurisdiction. |
| Maintenance and replacement interval | Follow testing, cleaning, battery and end-of-life instructions so the alarm remains operational. |
| Local code compatibility | Confirm that the installation and device type meet applicable building, electrical or fire-safety requirements. |
Test and maintain any alarm as directed, but respond to its warning exactly as you would to a suspected leak: leave immediately, avoid ignition sources and call from safety. Never silence an alarm by removing its power or assume a quiet detector proves that an area is safe.
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Common mistakes to avoid
- Searching for the source first: Gas may be accumulating in a concealed space or spreading beyond the room where it is noticed.
- Calling from inside: A phone or electrical contact can ignite gas; leave before calling.
- Opening windows as a first step: Ventilation must never delay evacuation or require operating a fixture.
- Driving away: Starting an engine in the suspected gas area introduces an ignition source; leave on foot.
- Assuming no odor means no leak: Odor may be absent or difficult for some people to detect, so heed sound and visual clues.
- Returning when the smell fades: Only officials can determine whether the hazard has been controlled.
- Relighting an appliance: A pilot or burner should remain off until the utility or a qualified professional authorizes use.
A concise emergency checklist
- Recognize odor, hissing or visual signs as a possible gas leak.
- Warn others without delaying your exit.
- Leave everyone and pets on foot.
- Move away and upwind when practical.
- Avoid switches, phones, flames, appliances, vehicles and valves in the suspected area.
- Call 911 for immediate danger and notify the gas utility or pipeline operator from safety.
- Do not return, relight equipment or restore gas service until officials declare the area safe.
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