Garage smells like gas or exhaust? Stay safe, then clear it

If your garage smells like gas, take it seriously before you worry about the odor itself. Gasoline vapor and engine exhaust are both a fire risk, and exhaust is also a carbon monoxide risk. Never run a car, mower, or generator in a closed garage, not even for a minute to warm up. If a gas smell is strong and persistent, it can be a real leak from a fuel line, a small engine, or a stored container, so ventilate the space, keep all flames and sparks away, do not flip switches, and if the smell is strong call your fire department or gas utility.

On the jobs we get called for around Greater Cleveland, the smell is usually left over after the source is already handled: a spilled gas can, a mower that seeped fuel, or exhaust that soaked into drywall and stored fabric over a winter of cold starts. Once the hazard is fixed, Odor Removal Experts clears the lingering gas or exhaust smell across Northeast Ohio with green, non-toxic methods. We never use ozone or chlorine.

Treat a strong gas or exhaust smell as a hazard first

A faint whiff of gas near the mower is one thing. A strong, persistent gasoline smell that fills the garage is another, because gas vapor is heavier than air and pools low where it can reach an ignition source.

Exhaust is its own danger. Carbon monoxide is odorless, but exhaust carries it, so a garage that smells of exhaust can be filling with CO. Never leave a car or generator running in a closed or attached garage, since CO can seep into the house. If you feel a headache, dizziness, or nausea, get outside into fresh air and call 911.

If a strong gas smell will not clear, or you cannot find the source, call your fire department or gas utility. They have meters that find what your nose cannot, and they respond to suspected leaks at no charge. For a gas smell inside the living space rather than the garage, see what to do when your house smells like gas.

• Never run a car, mower, or generator in a closed garage
• Gas vapor pools low and can reach a pilot light or switch, so no flames or sparks
• Exhaust carries carbon monoxide, which is odorless, so get to fresh air if you feel sick
• Strong or unexplained gas smell means a call to the fire department or gas utility

Common reasons a garage smells like gas or exhaust

Once the space is safe, most garage gas smells trace to a handful of sources. Bare concrete is porous, so a small spill that dried on the slab keeps off-gassing for a long time, and a car with an exhaust leak makes idling smells worse.

Check under and around a mower, trimmer, snowblower, or generator for damp spots or a fuel sheen, since aging carburetors and fuel lines weep fuel even when nothing is running. Exhaust smell usually comes from cold starts and idling, and over years that soot and odor settle into drywall, insulation, and anything stored against the walls.

• Stored gasoline: a loose or vented cap, an old can that seeps, or fuel in a mower or generator
• A dried spill on bare concrete that keeps off-gassing
• A leaking small engine weeping fuel from aging carburetors or fuel lines
• Exhaust from cold starts and idling soaking into drywall and stored items

Clear the air and cut the source yourself

Once the source is safe, you can knock most of the smell down yourself before any deeper treatment.

1. Air it out fully. Open the garage door and any windows to clear the vapor before anything else.
2. Move the fuel out. Take gas cans, the mower, and other fuel-holding equipment outside or to a detached shed, and store fuel in sealed, approved containers away from the house and any ignition source.
3. Lift a fresh spill. Spread cat litter, baking soda, or a dedicated oil-and-gas absorbent over the spill, let it sit, sweep it off, and repeat until it stops pulling more up.
4. Degrease and rinse. Scrub the spot with a degreaser and rinse, though a big spill soaked deep into the slab may hold odor a surface scrub cannot finish.

A leaking mower or a car exhaust leak should go to a mechanic.

How we remove a lingering gas or exhaust odor

When gas or exhaust has soaked into concrete, drywall, insulation, or stored items and scrubbing does not finish it, we remove it at the source. We never mask it with fragrance, and we never use ozone or chlorine. Our methods are green and non-toxic, and they are safe to run while you keep using the space.

• Enzymatic and oxidizing treatment of the slab and porous surfaces
• Thermal fogging to reach where the vapor traveled
• Occupied-safe hydroxyl generators
• HEPA and activated-carbon air scrubbing, plus sealing concrete that holds a deep smell

Most garages are done in 1 to 4 hours.

If the smell really came from a car rather than the garage itself, our guide on getting gasoline smell out of your car covers that, and a wider home odor removal handles exhaust that drifted from an attached garage into the house.