Home » Home Safety » Spotting Gas Leak Symptoms and Staying Safe

Spotting Gas Leak Symptoms and Staying Safe

Gas is the most widely used energy source, heating homes across the globe. It’s something we take for granted. 

Unfortunately, we also take its dangers for granted.

Whether you’re new to a property or have lived there your entire life, learning how to spot the signs of a gas leak is extremely important in ensuring the safety of the inhabitants of your home. 

Get to know boiler gas leak symptoms like the back of your hand, like how to identify the unmistakable gas leak smell.

Read on to learn all about gas leaks, as well as how to detox from natural gas poisoning after it’s occurred and how to prevent a leak in the first place.

How To Tell If You Have a Gas Leak

Thankfully, there are several rather telling signs of a gas leak that you can familiarize yourself with so that you’ll be quick to spot it should you have suspicions.


Though this might come as a surprise, gas actually has no odor; gas companies are obligated to odorize it to make it safer for use in homes. 

Mercaptan, a harmless chemical, is added to create the distinct smell in both natural gas (methane) and liquid petroleum gas (propane, butane). Carbon monoxide, however, has no scent.

Blue flame burns on a gas burner


Aside from scent, there are auditory signs that are obvious as well; if a gas pipe is broken, you’ll likely notice a whistling sound, like that of a boiling kettle, or a quiet hissing sound near a gas line. 

This is a tell-tale sign of a gas leak, but it won’t always happen.


Visual signs to look out for include bubbled water, dusty clouds near gas lines, and physical damage sustained to the gas pipe.

Gas leaks of any kind will alter the composition of air in your home, causing physical symptoms like headaches, fatigue, and dizziness. 

Those with existing breathing problems, like asthma, will experience an obvious flare up in symptoms. More severe gas leak symptoms include nausea and nosebleeds, which may indicate carbon monoxide, LPG, or natural gas poisoning.


Gas leak symptoms in dogs, cats, and plants are also worth looking out for, since they will likely be affected faster. 

Animals will exhibit similar symptoms to humans, but since they have smaller lungs, they are likely to have a significantly worse reaction, like passing out and vomiting. Houseplants near the leak will wilt and die suddenly.

A cat and a dog lay in the grass

Types of Gas Leaks

When we talk about gas leak symptoms and the signs of a gas leak, there’s a high chance we could be talking about different things, because there are different types. 

Though the symptoms and signs are similar, it’s important to have an idea of the different types of gas leaks that can occur in the home so you know what you’re dealing with. However, if you’re only here for the quick fixes, feel free to go directly to the next section.

Natural Gas Leak

‘Natural gas’ is methane. It’s formed over thousands of years and is extracted in every continent in the world, making it one of the most prominent causes of climate change. 

Slow gas leak symptoms will be less obvious (headaches, for instance, rather than passing out), but it’s still important not to use any electrical devices, flip any switches or cook anything. 

Natural gas is highly combustible, meaning an explosion or fire could occur should something ignite it. The danger this poses is far more worse than exposure to natural gas.

Gas works in Seattle, Washington

Liquid Petroleum Gas (LPG)

LPG refers to other hydrocarbon gasses stored as liquids. This is mostly propane, which may be mixed with butane or propylene. 

LPG is freezing, so approaching it could easily cause cold burns. It is also highly flammable, so electrical switches and sources of ignition should not be touched under any circumstances. 

Like natural gas, mercaptan is added to create a universally recognizable smell.

Person heats a pan for cooking using a propane canister

Carbon Monoxide

The presence of carbon monoxide is caused when gas (or coal or wood) doesn’t burn properly. It will emit from gas appliances, like cookers, heaters, and boilers, that don’t burn properly due to poor maintenance, fitting, or construction. 

Unlike methane and propane, carbon monoxide is odorless and colorless, making it much harder to detect. That makes it much more dangerous.

Carbon monoxide leaks aren’t impossible to spot, however. 

Symptoms of being poisoned are like those caused by exposure to other types of gas leak, but they are likely to be much more severe. 

The easiest and most reliable way to detect it is by installing carbon monoxide alarms in your home, which will sound when carbon monoxide is detected. 

Aside from that, keep an eye on your appliances: floppy stove flames or pilot lights that burn yellow/orange rather than blue suggest the presence of carbon monoxide. 

Staining, soot, and smoke may also indicate it.

Burning coals

Freon/Liquid Coolants

Fridges and AC units use chemical coolants colloquially referred to as ‘Freon’, though this is technically a brand name. Freon provides the cool air by undergoing a constant process of evaporation.

If you suspect an AC gas leak or a fridge gas leak, it’ll likely be much more obvious than other types of gas leaks, because there’s a high chance that there will be considerable structural damage to the product itself, like a puncture.

Even if structural damage isn’t obvious, you’ll notice the fridge or AC fails to work as it should, or may even stop working altogether. The AC may produce hot air, for instance, or make a buzzing sound, while the fridge may defrost and fail to keep food adequately cool.

White air conditioner

What To Do If You Have a Gas Leak

If you suspect a gas leak, taking those suspicions seriously and acting fast is crucial to mitigating the situation. Remain calm and follow these tips.

In The Event of a Natural Gas or LPG Leak

1. Evacuate children, elderly, and pets.

Children should be sent outside immediately, as well as elderly and those with existing health issues. Pets should also be taken outside.

2. Open all the windows in the property.

Open windows throughout the entire property, leaving some doors open as well to improve airflow and encourage oxygen circulation.

3. Turn off the gas at the mains.

If you suspect a natural gas leak, turn off the gas via the mains, even if the stovetop or gas oven is on. If the leak is coming from a propane canister, do not approach it. 

Likewise, do not flip any switches or touch any electrical devices; an electrical spark can easily ignite gas.

4. Call 911 or your local gas service.

From a safe location outside, you can call 911. If you know of a local servicer, you can also call them.

5. Re-enter the property after confirmation from a professional.

Do not go back inside the property until the professional that is sent to assess it has given you the all-clear.

After a Gas Leak

The professional who comes to assess your property should give you a full run-down on what to do in the immediate aftermath of the gas leak. This will be different depending on the cause and type of gas leak. For Freon leaks, check if you have a warranty and have a professional repair the product causing the leak. Until they arrive, simply turn the product off.

If you feel unwell, do not hesitate to inform the professional who comes to survey the property. If you have called emergency services, medics will be able to assess you and your family.

Ways to Prevent a Gas Leak In House

Preventing a gas leak is not the most straightforward of tasks, but there are certain precautions you must take.

CO alarms

Battery checking

Alarms will be powered by battery, so it’s important that you get into the habit of checking its power every month. Likewise, fire alarms should also be checked regularly.

Regular maintenance

All reputable energy providers should provide 24-hour maintenance and emergency service. If you feel your boiler hasn’t been serviced in some time, call the provider, and arrange for a professional to assess it. Similarly, products that use liquid coolants like air conditioners and refrigerators should be assessed. Building habits is wise when it comes to taking preventative measures.


In a general sense, ensuring your home has good ventilation will help prevent poisoning, so make sure to keep ventilation shafts and cooker fans clean and in working order. If you are burning a fire, make sure the chimney has regular cleaning and maintenance. Barbecuing, or any form of cooking that uses propane or coal, should be done in large open spaces.


How can you tell if you have a gas leak?

It helps to think of the five senses: if you can’t see it, you can probably smell it. If you can’t smell it, you can probably hear it. But under no circumstances should you ever touch what appears to be a gas leak; sustaining cold burns can be extremely dangerous.

Will a carbon monoxide detector detect a gas leak?

A carbon monoxide detector sounds when it detects dangerous levels of CO in the air. There is a high chance that, should this occur, there is probably a gas leak somewhere. But it doesn’t suggest anything conclusive about the source. Carbon monoxide is created when gas burns improperly.

What does gas smell like?

Natural gas and liquid petroleum gas (propane, butane, etc.) will be scented with the harmless chemical mercaptan, which is used as an olfactory warning sign. It smells sulfuric, like rotten eggs or cabbage, so you can’t miss it. Coolants like Freon are also pungent, with a scent like nail varnish or chlorine. 

Can inhaling gas make you sick?

Yes. As the composition of the air changes, less oxygen will be in your blood. At a certain point, this could asphyxiate you and cause death. Symptoms to look out for include headaches, dizziness, and nausea. More severe symptoms include passing out, breathing problems, and nosebleeds.

Should you open windows if you smell gas?

Absolutely. After evacuating children, sick and elderly, and pets, you should immediately open all the windows in your property to ventilate it, thereby increasing the amount of oxygen in the air. You should then also quickly exit the property. This does, of course, pose a security risk; with AlfredCamera, you can quickly place a device to observe rooms with opened doors and windows, so that you can keep watch on your phone while you wait at a safe location outside.

How to detox from natural gas poisoning?


Knowing gas leak symptoms and signs to look out for can mean the difference between life and death, and it’s important that if you have suspicions, you take them seriously. Don’t second guess yourself; it’s better to be safe and cautious.