vehicle repair safety

This webpage is appropriate for home mechanics and professional shops.

This page is homework for my first aid classes and is quite detailed, but is not complete information on the subject.


According to the CDC (Centers for Disease Control),
important health and safety issues in automotive (and motorcycle) repair include:

– – Injuries involving sprains, strains, cuts (also known as lacerations or avulsions) and bruises (also known as contusions).

– – Slips, trips and falls

– – Overexertion

– – Injury from sources such as hand tools, vehicles, parts/materials, floor surfaces

– – Fatalities from fires/explosions and contact with objects or equipment, especially struck by falling objects

– – Exposure/over-exposure to chemicals, biological materials, vehicle exhaust and asbestos


From U.C. Berkeley Wellness:

Wearing jewelry while working on your car is not a good mix, according to several reports, including one in 2013 in Orthopedics. An auto mechanic suffered a significant burn on his finger when his gold ring touched the positive terminal of a 12-volt car battery and the wrench he was holding touched both the gold ring and the battery’s negative terminal. This completed a circuit, resulting in an electrical burn. Gold is a good conductor of both electricity and heat, the paper noted.”


The following is copyrighted by and used by permission of Haynes Manuals:

Safety first!

Regardless of how enthusiastic you may be about getting on with the job at hand, take the time to ensure that your safety is not jeopardized. A moment’s lack of attention can result in an accident, as can failure to observe certain simple safety precautions. The possibility of an accident will always exist, and the following points should not be considered a comprehensive list of all dangers. Rather, they are intended to make you aware of the risks and to encourage a safety conscious approach to all work you carry out on your vehicle.

Essential DOs and DON’Ts

DON’T rely on a jack when working under the vehicle. Always use approved jackstands to support the weight of the vehicle and place them under the recommended lift or support points.

DON’T attempt to loosen extremely tight fasteners (i.e. wheel lug nuts) while the vehicle is on a jack – it may fall.

DON’T start the engine without first making sure that the transmission is in Neutral (or Park where applicable) and the parking brake is set.

DON’T remove the radiator cap from a hot cooling system – let it cool or cover it with a cloth and release the pressure gradually.

DON’T attempt to drain the engine oil until you are sure it has cooled to the point that it will not burn you.

DON’T touch any part of the engine or exhaust system until it has cooled sufficiently to avoid burns.

DON’T siphon toxic liquids such as gasoline, antifreeze and brake fluid by mouth, or allow them to remain on your skin.

DON’T inhale brake lining dust – it is potentially hazardous (see Asbestos below).

DON’T allow spilled oil or grease to remain on the floor – wipe it up before someone slips on it.

DON’T use loose fitting wrenches or other tools which may slip and cause injury.

DON’T push on wrenches when loosening or tightening nuts or bolts. Always try to pull the wrench toward you. If the situation calls for pushing the wrench away, push with an open hand to avoid scraped knuckles if the wrench should slip.

DON’T attempt to lift a heavy component alone – get someone to help you.

DON’T rush or take unsafe shortcuts to finish a job.

DON’T allow children or animals in or around the vehicle while you are working on it.

DO wear eye protection when using power tools such as a drill, sander, bench grinder, etc. and when working under a vehicle.

DO keep loose clothing and long hair well out of the way of moving parts.

DO remove rings, wristwatch etc., before working on the vehicle – especially the electrical system.

DO make sure that any hoist used has a safe working load rating adequate for the job.

DO exercise caution when compressing springs for removal or installation. Ensure that the tension is applied and released in a controlled manner, using suitable tools which preclude the possibility of the spring escaping violently.

DO get someone to check on you periodically when working alone on a vehicle.

DO carry out work in a logical sequence and make sure that everything is correctly assembled and tightened.

DO keep chemicals and fluids tightly capped and out of the reach of children and pets.

DO use a barrier cream on your hands prior to undertaking dirty jobs – it will protect your skin from infection as well as making the dirt easier to remove afterwards; but make sure your hands aren’t left slippery. Note that long-term contact with used engine oil can be a health hazard.

DO keep your work area tidy – it is only too easy to fall over articles left lying around.

DO remember that your vehicle’s safety affects that of yourself and others. If in doubt on any point, get professional advice.

IF, in spite of following these precautions, you are unfortunate enough to injure yourself, seek medical attention as soon as possible.

Steering, suspension and brakes

These systems are essential to driving safety, so make sure you have a qualified shop or individual check your work. Also, compressed suspension springs can cause injury it released suddenly – be sure to use a spring compressor.


Airbags are explosive devices that can cause injury if they deploy while you’re working on the vehicle. Follow the manufacturer’s instructions to disable the airbag whenever you’re working in the vicinity of airbag components.


Certain friction, insulating, sealing, and other products – such as brake linings, brake bands, clutch linings, torque converters, gaskets, etc, – may contain asbestos or other hazardous friction material. Extreme care must be taken to avoid inhalation of dust from such products, since it is hazardous to health. If in doubt, assume that they do contain asbestos.


Remember at all times that gasoline is highly flammable. Never smoke or have any kind of open flame around when working on a vehicle. But the risk does not end there. A spark caused by an electrical short circuit, by two metal surfaces contacting each other, or even by static electricity built up in your body under certain conditions, can ignite gasoline vapors, which in a confined space are highly explosive. Do not, under any circumstances, use gasoline for cleaning parts. Use an approved safety solvent.

Always disconnect the battery ground (-) cable at the battery before working on any part of the fuel system or electrical system. Never risk spilling fuel on a hot engine or exhaust component. It is strongly recommended that a fire extinguisher suitable for use on fuel and electrical fires be kept handy in the garage or workshop at all times. Never try to extinguish a fuel or electrical fire with water.


Certain fumes are highly toxic and can quickly cause unconsciousness and even death if inhaled to any extent. Gasoline vapor falls into this category, as do the vapors from some cleaning solvents. Any draining or pouring of such volatile fluids should be done in a well ventilated area.

When using cleaning fluids and solvents, read the instructions on the container carefully. Never use materials from unmarked containers.

Never run the engine in an enclosed space, such as a garage. Exhaust fumes contain carbon monoxide, which is extremely poisonous, If you need to run the engine, always do so in the open air, or at least have the rear of the vehicle outside the work area.

The battery

Never create a spark or allow a bare light bulb near a battery. They normally give off a certain amount of hydrogen gas, which is highly explosive.

Always disconnect the battery ground (-) cable at the battery before working on the fuel or electrical systems (except where noted).

If possible, loosen the filler caps or cover when charging the battery from an external source (this does not apply to sealed or maintenance-free batteries). Do not charge at an excessive rate or the battery may burst.

Take care when adding water to a non maintenance-free battery and when carrying a battery. The electrolyte, even when diluted, is very corrosive and should not be allowed to contact clothing or skin.
Always wear rubber gloves. Always wear eye protection when cleaning the battery to prevent the caustic deposits from entering your eyes.

Household current

When using an electric power tool, inspection light, etc., which operates on household current, always make sure that the tool is correctly connected to its plug and that, where necessary, it is properly grounded. Also ensure that the appliances meet national safety standards. Do not use such items in damp conditions and, again, do not create a spark or apply excessive heat in the vicinity of fuel or fuel vapor.

Secondary ignition system voltage

A severe electric shock can result from touching certain parts of the ignition system (such as the spark plug wires) when the engine is running or being cranked, particularly if components are damp or the insulation is defective. In the case of an electronic ignition system, the secondary system voltage is much higher and could prove fatal.

Hydrofluoric acid

This extremely corrosive acid is formed when certain types of synthetic rubber, found in some O-rings, oil seals, fuel hoses, etc. are exposed to temperatures above 750-degrees F (400-degrees C). The rubber changes into a charred or sticky substance containing the acid. Once formed, the acid remains dangerous for years. If it gets onto the skin, if maybe necessary to amputate the limb concerned.
When dealing with a vehicle which has suffered a fire, or with components salvaged from such a vehicle, wear protective gloves and discard them after use.

– – – These safety rules are mentioned in Haynes motorcycle books, along with the automotive rules above:

DON’T inflate a tire to a pressure above the recommended maximum. Apart from over stressing the carcase and wheel rim, in extreme cases the tire may blow off forcibly.

DO ensure that the machine is supported securely at all times. This is especially important when the machine is blocked up to aid wheel or fork removal.

If you ever need to prepare battery electrolyte yourself, always add the acid slowly to the water; never add the water to the acid.





A brief lesson in electricity. When you plug an appliance into a wall outlet and turn it on, it does not use up all the electricity coming to it. The electricity returns into the wall outlet. A special type of outlet, a ground fault circuit interrupter (GFCI), constantly monitors the returning current. The GFCI can prevent electrical shock by noticing the difference in the current and shutting off the current to the appliance/power tool (in as little as one-thirtieth of a second!). If the current does not return because it goes to ground… (for example through you or other people), it could be because you:

work out in the rain with a power tool that has a frayed wire and the wet ‘hot’ wire sends the electricity into you


don’t have a long enough ‘suitable for use with outdoor appliances’ extension cord, so you string together a few that are not labeled for outdoor use, and not suitable for the distance/wattage of the mega-bright decorating lights you want to use, and the cord comes in contact with puddles and sends electricity into you


put a boom box on a starting block next to a swimming pool and it falls in, sending the electricity into the pool water and the aqua aerobics class members

ground fault interrupter: ground fault interrupter safety outlet Please note that GFCIs can be damaged by lightning or other electrical surges and need to be tested regularly. Since they (ground fault circuit interrupters) might not always be functional, putting that boom box/radio/hairdryer/electric heater where it can fall into the watercraft test tank/swimming pool/spa/hot tub/bathtub/kitchen or shop sink full of water/ is never a good idea.


fire extinguisher:

Someday you may need an A B C type fire extinguisher in the garage, kitchen and each car (and on both floors of a 2 story home) .

Choosing and Using Fire Extinguishers

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

After the earthquake you should know how and when to turn off gas, electricity and water.
The PG&E guide with lots of pictures, on how and when to turn off your gas is at:

You might want to print and post a copy of it.

See also: Do it yourself earthquake preparedness

hazardous household chemical mixtures (Many people know that ammonia mixed with bleach creates a toxic gas. Therefore we should not only not mix them to clean, we should store them apart from each other to they can’t spill and mix during the shaking of an earthquake.)


Thinking about using a portable heater in the shop, or even in the office next to the shop? Go to: Home Fire Safety Checklist and scroll down to Portable Electric Heaters. Keep portable heaters away from any flammable fumes.



Antifreeze (ethylene glycol) smells sweet to a cat, dog, or perhaps even a toddler. When you flush it into a container on the ground/floor do not leave it sitting. Dispose of it promptly.

Store, use and dispose of all chemicals according to the instructions on the original container.

Poison control can be contacted for emergency information about swallowing poisons, eye or skin irritation from poisonous substances, inhalation of poisonous fumes (and more) at 1 800 222-1222. You might want to put the number right next to the phone(s).


For road trips, we advise people to check everything that
and lights their vehicle
before they leave on an adventure.

See: Road trip vehicle prep and recommended service

The page has an explanation of why you would do this:

car wrapped in a tarp


OSHA (Occupational Safety & Health Administration) Safety Bulletins on

Asbestos-Automotive Brake and Clutch Repair Work

Hazards while Servicing Light Truck,
Automobile, and Other Small Tires

Vehicle-mounted Elevating and Rotating Devices

and there are more Safety Bulletins at:

The author of this webpage, (written as a homework reading assignment for my students), does not give any warranty, expressed or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, product, or process included in this website or at websites linked to or from it. Users of information from this website assume all liability arising from such use.