Most of the hazards are manageable — they just need to be accounted for.
01Carbon Monoxide
Vehicle exhaust
Never run a car in the garage, even with the door open. CO builds faster than it can vent through a standard open garage door. A one-car garage with the door open and an idling vehicle reaches dangerous CO levels in under two minutes. Run the engine outside or not at all.
CO detector
If the garage shares a wall with living space, a CO detector in the adjacent interior room is warranted. Install one at sleeping-area height — CO accumulates at lower concentrations before rising, and the garage-to-house pathway can expose sleeping occupants before they're aware of it.
Gas appliances
If you have a gas water heater or furnace in the garage, confirm the unit is raised 18 inches off the floor on a platform (required by code in garages where flammable liquids are stored) and that the area around it is clear of combustibles.
02Flammable Storage
Gasoline and fuel storage
Gasoline should be stored in approved metal or HDPE containers, sealed, away from any ignition source, and in a quantity no greater than what you'll use within 30 days. Stale gas is a performance problem; gas stored near a water heater pilot light is a safety problem.
Chemical segregation
Oxidizers (pool chemicals, fertilizers with nitrates) should never be stored near flammable liquids or solvents. A spill that causes contact between these categories can ignite without any additional spark or flame.
Spray cans
Aerosol cans of paint, lubricants, and solvents are pressurized flammable containers. Store them upright, away from heat sources, and away from anything with a pilot light.
03Electrical
GFCI outlets
All garage outlets are required to be GFCI-protected under current code. Test each one. A garage that was wired before GFCI requirements applied may have standard outlets — an electrician can retrofit them for $15–$30 per outlet.
Extension cords
In a workspace, extension cords see more mechanical stress than in any other room. Inspect them for cracking, fraying, or damaged plugs. A damaged extension cord in a shop environment is a replacement, not a repair.
Overhead door opener
The auto-reverse function on a garage door opener should be tested annually. Place a 2x4 flat on the ground in the path of the door and close it — the door should reverse when it contacts the board. If it doesn't, adjust the force settings per the manufacturer's instructions. A door that doesn't auto-reverse is a crush hazard.
04Tools and Equipment
Power tool storage
Power tools with exposed blades — circular saws, reciprocating saws, jigsaws — should be stored with blade guards in place and in a location not accessible to children. A wall-mounted rack or enclosed cabinet accomplishes both.
Ladder storage
Extension ladders stored horizontally across a wall should be mounted at a consistent height that doesn't create a head-strike hazard when walking through the garage. Metal hooks into studs at the correct height is the standard solution.
Compressed air
If you have an air compressor, the tank should be drained monthly to remove accumulated water, which causes interior rust and eventual tank failure. A rusted air tank under pressure is a catastrophic failure risk.
05General
Fire extinguisher
A garage should have its own fire extinguisher — a 5-lb ABC-rated unit mounted near the door to the house. The kitchen extinguisher is not the garage extinguisher.
Door to house
The door between the garage and the house interior is required to be fire-rated (20-minute minimum) and self-closing under current code. If yours is a standard hollow-core door or doesn't self-close, this is a code deficiency worth correcting.
Every 6 months. Before any season where fuel storage increases — lawn care season, winter generator prep. After any new gas appliance installation.
Ray Torres is a home safety writer based in Phoenix, Arizona. He writes about the slow, quiet hazards in residential buildings — the ones that have been sitting slightly wrong for long enough that nobody notices them anymore.