What to do if you smell gas
A rotten-egg smell can mean a natural gas or propane leak. Get everyone out first, then call for help from a safe distance. Don't look for the leak yourself.
Natural gas has no smell on its own. Utilities add an odorant called mercaptan so a leak smells like rotten eggs or sulfur. Propane is odorized the same way. If you notice that smell indoors, treat it as a leak until someone qualified tells you otherwise.
This is one of the few home problems with no DIY step. Your only jobs are to get people out, avoid making a spark, and call for help from a safe place. Gas companies offer 24-hour emergency response for exactly this.
Do this right now
- Get everyone out. People and pets, out the nearest door.
- Don't create a spark. Don't flip light switches on or off, use phones, ring the doorbell, adjust the thermostat, open the garage with the remote or start a car in the garage. Don't light matches, candles or lighters.
- Move well away. Go to a neighbor's home or far enough down the street that you can't smell gas.
- Call for help from there. Call 911 and your gas utility's emergency number. For propane, call your propane company. Explain what you smell or hear and where.
- Warn others. If it's safe, keep neighbors and passers-by away from the area.
- Wait for the all clear. Don't go back inside until the gas company or fire department says it's safe.
What not to do
- Don't try to find or fix the leak yourself, indoors or out.
- Don't use phones or anything electrical that could spark near the smell.
- Don't start a car, mower or other engine near the smell.
- Don't turn the gas back on after it has been shut off for safety. The utility or propane company does that after checking the system.
If the smell is faint
A faint whiff right near a stove can come from a burner knob left slightly open or a pilot light that went out. Gas safety regulators say that if you can safely fix that, such as turning a knob fully off, it may solve the problem. If you're not sure, or the smell doesn't fade quickly, don't take chances. Leave and call from outside.
If you smell gas outdoors
Report it right away to your gas utility or 911. Don't try to trace the source. Signs of an underground leak include a hissing or roaring sound, dead or discolored plants, or a mist or vapor cloud. Don't drive into the area or run powered equipment nearby.
Gas leaks and carbon monoxide are different
People often mix these up. They are different dangers with different warnings.
| Natural gas or propane leak | Carbon monoxide (CO) | |
|---|---|---|
| What it is | Unburned fuel escaping from a line, tank or appliance | A poison gas made when fuel burns incompletely |
| Smell | Rotten eggs, from the added odorant | None. CO is colorless and odorless |
| Main risk | Fire or explosion | Poisoning, which can kill within minutes |
| Warning | Your nose, or a gas detector | Only a CO alarm |
If your CO alarm sounds, NFPA advises moving right away to fresh air outdoors or by an open window or door, making sure everyone is accounted for, and calling for help from there. Stay out until emergency responders say it's safe.
CPSC recommends a CO alarm on every level of your home and outside each sleeping area, either battery-powered or plug-in with battery backup. Test them monthly. Put alarm tests and a yearly furnace inspection on your fall maintenance checklist.
After the leak is found
Once the utility makes things safe, gas line repairs must be done by a licensed professional or the gas company, following local rules. Never DIY gas piping or appliance gas connections. A licensed plumber or HVAC technician can repair the leak and safely relight appliances. Renters should notify the landlord right away.
Prepare now
- Save your gas utility's or propane supplier's emergency number in your phone and on your home emergency card.
- Make sure everyone in the house knows the rotten-egg smell means get out.
- Install CO alarms and test them monthly.
- Have fuel-burning heating equipment inspected by a professional every year.
Common questions
Why does natural gas smell like rotten eggs?
Natural gas has no smell of its own. Gas companies add an odorant called mercaptan so you can notice a leak.
Can I use my cell phone to call about a gas leak?
Not inside or near the smell. Phones can create a spark. Get outside and well away from the building, or go to a neighbor's home, and call from there.
Will my carbon monoxide alarm detect a gas leak?
No. A CO alarm detects carbon monoxide, a different gas made when fuel burns poorly. It is not designed to sense natural gas or propane. Your nose, or a separate gas detector, is the warning for a leak.
Can I turn the gas back on myself after a leak?
No. Once the gas has been shut off for safety, let your gas utility or propane company inspect and restore it.