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Surface Preparation

The second step in a typical auto repair is surface preparation. During this step filler may be applied to fill voids and the surface sanded smooth. Other painted surfaces may be sanded or roughed up so that it will hold the new paint. Just prior to painting, the vehicle is cleaned, taped or masked to protect areas that will not be painted, and any dust or oil is removed with a solvent. Taping does not involve any chemical hazards.

Watch the video called Surface Preparation…

Body filler or bondo contains styrene which can cause cancer.

Applying Body Filler / Bondo

The application of filler material can expose you to some hazardous materials if you do not take appropriate precautions. Most body fillers contain a solvent called styrene. As the filler dries, styrene is released to the air and you can breathe it. It has a characteristic sweet smell at low concentrations and a sharp disagreeable odor at high concentrations.

Exposure to styrene can cause respiratory irritation. It may also damage your liver and possibly cause cancer at very high levels of exposures - not usually found in autobody shops. Styrene can also be absorbed directly through the skin if you come in direct contact with the uncured filler. In some people, direct contact with the filler may cause skin rashes and repeated exposure may increase your sensitivity.

PPE and controls

Wear gloves to keep body filler off your hands.

When mixing and applying filler material, you should:

  • wear gloves that are resistant to styrene (such as PVA or polyethylene) and eye protection
  • mix and apply filler where there is adequate general ventilation arranged to draw the styrene vapors away from you and others working in the area, such as in a prep station
  • wear a respirator fitted with organic vapor cartridges if you are sensitive to the odors - change the cartridges regularly and as soon as you can smell the styrene while wearing the respirator
  • wash your hands and exposed skin surfaces thoroughly after applying the filler


Sanding paint and filler material creates a lot of fine dust that is easily inhaled and can irritate your breathing tubes and eyes. The dust may contain hazardous substances as well, such as lead, chromium, and the abrasives from sanding disks. This dust can be harmful if inhaled or ingested. We are not suggesting that anyone eats the dust on purpose, but it can easily stick to your hands and face, and if not thoroughly washed off, will contaminate your food, drinks and cigarettes. At even very low levels of exposure, the toxic metals in this dust can cause serious health affects and body workers performing these tasks without precautions have exceeded the exposure limits for these hazardous materials.

Wear gloves, respirator, goggles and coveralls to protect against sanding dust.

What can you do to protect yourself while sanding old paint or filler material?

  • Wear gloves to keep your hands clean - you are less likely to contaminate your food and ingest the dust.
  • Wear a respirator to keep from inhaling the dust - choose a respirator or cartridge able to filter these fine dusts.
  • Wear goggles to protect your eyes.
  • Wear coveralls which can be removed and left in the shop - keep the dust off your clothing, car and home. Young children are more severely affected when exposed to these hazardous materials.
  • Remove your coveralls and gloves in the shop when you finish sanding - before using the restroom and before going for coffee breaks or lunch.
  • Leave coveralls in the shop - throw away or wash in a commercial laundry.
  • After removing dusty gloves and clothing, wash your hands, arms and face thoroughly with soap and water.
  • Eat or drink in a clean lunchroom or outside the shop.
  • Use a vacuum cleaner instead of compressed air to blow dust off yourself - everyone in the shop won't have to breathe the dust.
  • Use a locally exhausted sander to keep down dust levels.
  • Some shops have also found that wet sanding can be used effectively.

Read more about dusts…

Wear gloves when wiping down a car with solvent.

Solvent Wipe Down

Surface cleaning may involve solvents such as isopropyl alcohol to remove any remaining dust or grease. You should wear gloves when using solvents to wipe down these surfaces, and do this in areas with good general ventilation. Wear goggles if there is a chance you can be splashed in the face.

Read more about solvents…


Detailing involves cleaning the surfaces of a car. Of course water is not harmful, but many different cleaning products are used to clean lights, tires, hubcaps, interiors, etc. Check the labels on these products - some contain solvents that should be used with care. If detailing any freshly-painted surfaces, wear gloves to protect your skin against the isocyanates that continue to rub off the car for days and weeks after painting.

Wear a respirator and gloves when using a stripper containing methylene chloride.

Chemical Stripping of Paint

Some shops still use a solvent called methylene chloride to strip paint. Methylene chloride evaporates rapidly when applied to surfaces and once airborne is readily inhaled. Exposures during this operation can exceed safe levels and can cause irritation, drowsiness and nausea. It is also believed to cause cancer. Solvent stripping of paint coatings should be avoided, but if absolutely necessary, this activity should be done in an area with adequate ventilation such as a paint spray booth or vented prep station. Gloves, an apron or suit, goggles, and respiratory protection should be worn.