What to Do If You Smell Gas in Your Apartment: Get Out First, Then Call, and the Mistakes That Cause Explosions

Quick answer: if you smell gas (often described as rotten eggs or sulfur), leave the apartment immediately and get others out, without turning lights or appliances on or off, using a phone, lighting anything or ringing a doorbell inside. Leave the door open behind you if you can do it quickly. Once you are a safe distance away, call 911 or your gas utility’s emergency number. Do not try to find the leak and do not go back in until emergency responders or the utility say it is safe. Only turn off gas at the meter if you have been trained and it is safe, and remember that only the utility should turn it back on.

Natural gas is common in city buildings, powering stoves, water heaters, dryers and furnaces. It is safe when contained, but a leak can lead to a fire or explosion, and in apartment buildings one leak can affect many households.

The right response is simple, but it runs against instinct. Many people want to find the source, open every window or call someone from the kitchen. This guide explains what to do, in what order and why. It is part of our apartment emergency preparedness guide.

Sources: U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration (PHMSA), pipeline safety and leak recognition guidance; Common Ground Alliance, 811 “Call Before You Dig”; Ready.gov, “Home Fires” and utility shutoff guidance; National Fire Protection Association, NFPA 715, Standard for the Installation of Fuel Gas Detection and Warning Equipment, and natural gas and propane safety information; UL Standards & Engagement, UL 1484 for residential gas detectors. Your gas utility’s emergency instructions take priority. Checked October 2026.

Why Gas Smells Like Rotten Eggs

Natural gas has no smell on its own. Utilities add an odorant, commonly a sulfur-based chemical called mercaptan, so leaks can be detected by smell. Propane is odorized for the same reason. PHMSA describes the smell as similar to rotten eggs.

Smell is not foolproof. Some people have a reduced sense of smell from age, illness, medications or smoking, and in rare cases the odorant can fade, for example when gas passes through soil. That is why other warning signs, and detectors, matter.

Other signs of a leak

PHMSA lists signs of a natural gas pipeline leak that include:

• A hissing, whistling or roaring sound near a gas line or appliance
• Dirt or dust blowing from a hole in the ground
• Bubbles in standing water or a pond
• Dead or discolored vegetation in an otherwise green area
• Flames coming from the ground or a water surface, if a leak has ignited

Indoors, the smell is usually the first clue. A sound near an appliance connection is another.

The Right Order: Get Out, Then Call

Utilities and PHMSA give the same basic sequence.

1. Leave immediately. Get everyone out of the apartment, including pets if you can do it without delay.
2. Do not create a spark. Do not turn lights or appliances on or off, unplug anything, use a phone, ring a doorbell, start a car in an attached garage or light a match or lighter on your way out.
3. Leave the door open behind you if it is quick and easy, to let gas escape. Do not spend time opening windows.
4. Warn neighbors on the way only if it does not delay you. Knocking is safer than ringing an electric doorbell.
5. Move a safe distance away, outside the building or well down the street.
6. Call 911 or your gas utility’s emergency number from there, using your phone only once you are away from the smell.
7. Do not go back in until emergency responders or the utility tell you it is safe.

Do not try to locate the leak or fix it yourself. Responders have gas detectors and the training to find and stop it.

Why a phone or light switch matters

Many household electrical devices can produce a small spark when switched. In an area with enough gas in the air, a spark can ignite it. That is why the instructions stress leaving everything as it is and making the call from a distance.

In an Apartment Building

Apartment living adds a few wrinkles.

• Smell in the hallway or stairwell? Leave the building by the stairs, then call 911 or the utility. Do not use the elevator.
• Tell building management after you are safe and have called for help.
• Make sure neighbors who may need help evacuating are not forgotten. Our guide to an apartment building emergency plan with neighbors covers how to set that up ahead of time.

If you smell gas faintly near your stove and know a burner was left on unlit, the same caution applies. Do not try to relight it. Leave and call.

Natural Gas vs Propane

The two fuels behave differently when they leak, which affects detection.

	Natural gas	Propane
Weight compared with air	Lighter, tends to rise	Heavier, tends to sink and collect low
Where it collects	Near ceilings and upper areas	Near floors, basements and low spots
Common city sources	Utility lines to stoves, water heaters, dryers and furnaces	Grill tanks, portable heaters and camp stoves

Propane cylinders are often restricted in apartment buildings by fire codes and leases. If you smell propane, the same response applies: leave, then call.

Gas Leaks After Storms, Floods and Earthquakes

Disasters can damage gas lines and appliances, so leaks are a particular concern afterward. Ready.gov advises checking for gas leaks when returning home after a disaster, and leaving immediately if you smell gas or hear a hissing sound.

A few situations deserve extra caution:

• After flooding: gas appliances such as water heaters, furnaces and dryers that were underwater should be inspected by a qualified professional before use. Floodwater can damage controls, valves and burners.
• After an earthquake: shifting can loosen connections. Use a flashlight, not a match or candle, when checking your home, and follow your utility’s instructions.
• After high winds or fallen trees: outdoor meters and lines can be damaged. Stay away from damaged equipment and report it.
• During cleanup: do not use generators, grills or fuel-burning tools indoors, and keep anything with a flame away from areas where you smelled gas.

If your building was affected by a storm or flood, ask management whether the utility has inspected the gas system before you use gas appliances.

After the All-Clear

Once responders or the utility say it is safe to return:

1. Follow their instructions on which appliances can be used and whether service has been restored.
2. Let the utility or a professional relight pilot lights and restore service to appliances.
3. Get the problem repaired. In a rental, the landlord is generally responsible for gas appliance and line repairs. Report the incident in writing and keep a copy.
4. Document any damage with photos and notes, including dates and the names of people you spoke with. Our guide to renters insurance and a home inventory explains why records help with claims.
5. Watch for the smell returning. If it does, leave and call again.

Teach Everyone in the Household

Children, roommates, guests and caregivers should know the plan too. Make sure they can recognize the smell; some utilities offer scratch-and-sniff cards for this purpose. Keep the instructions short: smell gas, get out, do not touch switches, call from outside.

Gas Detectors

Smell is your main warning, but detectors add a backup, especially for people with a reduced sense of smell. Residential gas detectors are commonly listed to UL 1484, and the NFPA published NFPA 715, a standard for installing fuel gas detection and warning equipment.

Keep in mind:

• Gas detectors are not carbon monoxide alarms. Carbon monoxide comes from incomplete burning and has no smell; natural gas is the fuel itself. You need a CO alarm regardless. Our guide to carbon monoxide alarm placement and testing explains it.
• Placement depends on the gas. Because natural gas rises and propane sinks, follow the manufacturer’s instructions for mounting height.
• Combination units exist that detect both explosive gas and carbon monoxide.
• Check your lease before mounting anything permanently, and ask your landlord whether the building already has detection.

Shutting Off the Gas

Ready.gov advises learning where your gas meter and shutoff valve are, but it also warns that once gas is turned off, only a professional should turn it back on. In most apartment buildings, residents do not have access to the meter, and building staff or the utility handle shutoffs.

If you live in a house or a small building with an accessible meter:

• Only shut off gas if you smell gas or hear a leak and it is safe to reach the valve, or if officials instruct you to.
• Never turn it back on yourself. Call the utility to restore service and relight pilot lights.
• Keep the right tool near the meter if the valve requires a wrench.

Many appliances also have their own shutoff valve on the supply line. Know where it is, but in a suspected leak, leaving is still the first step.

Preventing Leaks

Most gas problems in apartments come from appliances and connections. To reduce risk:

• Report any gas smell, even a faint one, to the utility and your landlord.
• Do not move gas appliances or change connectors yourself; that is a job for building maintenance or a licensed professional.
• Keep burners clean and watch for yellow or flickering flames that may signal a problem.
• Never use a gas oven or stove for heat.
• Do not store flammable liquids or propane cylinders near gas appliances.
• Call 811 before digging if you garden or install anything in the ground at a house or ground-floor unit; the Common Ground Alliance runs the free 811 service so underground utility lines can be marked first.

Plan Ahead

A gas leak is one of those emergencies where knowing the steps before it happens makes the difference.

1. Save your gas utility’s emergency number in your phone.
2. Agree on a meeting spot outside the building with your household.
3. Practice getting out without turning anything on or off.
4. Keep shoes, keys and a flashlight near your bed or door so you can leave quickly at night.
5. Include gas leaks in your fire safety plan; our apartment fire safety plan covers exit routes you can reuse.

Renters: Know Your Building's Gas Setup

A few questions for your landlord or building manager, asked on a calm day, make an emergency easier:

• Which appliances in my unit use gas? Stoves are obvious, but water heaters, dryers and furnaces may be gas too.
• Where is the shutoff for my unit, and who is allowed to use it?
• Who should I call after hours for a gas problem, besides 911 and the utility?
• Does the building have gas detectors in common areas or boiler rooms?
• When were gas appliances last serviced?

Write the answers down and keep them with your emergency contacts. If you notice repeated faint gas odors, damaged connectors or scorch marks around an appliance, report them in writing so there is a record of the request.

Frequently Asked Questions

What should I do first if I smell gas?

Leave the apartment immediately with everyone else, without switching anything on or off. Call 911 or your gas utility once you are safely away.

Can I call from inside if I smell gas?

No. Utilities and safety officials advise making the call from a safe distance outside, since a device could produce a spark.

Should I open windows if I smell gas?

Do not spend time opening windows. Leave the door open behind you if it is quick, and get out.

Does a carbon monoxide alarm detect a gas leak?

No. CO alarms detect carbon monoxide, not natural gas or propane. Use a gas detector for that, and keep CO alarms too.

Can I turn the gas back on after it was shut off?

No. Only the utility or a qualified professional should restore gas service and relight pilot lights.

The Bottom Line

If you smell gas, do not investigate. Get everyone out, avoid anything that could make a spark, call 911 or your utility from a safe distance and wait for the all-clear. Add a gas detector and CO alarms, save your utility’s emergency number and practice a quick exit, so your household knows the plan without thinking.