At one time, it was more common for painters not to think very much about what they were breathing inside the spray booth or in the shop. Professional bodymen and painters working in purpose-built, well-equipped shops have traditionally been a step ahead of the once-in-a-while hobbyist working out of his garage. Employers must comply with specific regulations and procedures for selecting, using, and maintaining proper respiratory protection in the workplace that are contained in standards issued by federal, state, or government agencies, such as OSHA. Do-it-yourselfers and hobbyists are not similarly regulated, and exposures are less frequent and for shorter periods of time.

The hazards of breathing in isocyanates from paint, or airborne contaminants created by grinding and sanding and working with body filler, don't just affect professionals. Today, hot rodders are more aware of safety issues associated with paint and bodywork, and there are many high-quality respirators on the market to protect our health. Some of the products are expensive and some are relatively cheap-but all of them are worth it if you consider the risks of not using the proper respirators. We in the magazine biz have gotten used to reminding our readers to wear the proper respirator when painting, but we've never looked any further at the variety of products available and how they differ according to application. Respiratory protection isn't just for painting. Bodywork and other forms of metalwork, including welding, can release airborne particulates you don't want to inhale. If you can smell it, you're breathing it. If you can't smell it, you still might be breathing it. When you're talking about health risks, why take chances?

There are many companies making good-quality cartridge respirators and masks, but 3M is probably one of the best known. Its 16-page automotive respirators catalog, available on 3M's Web site, features a range of styles and designs of organic vapor (OV) cartridge respirators for painting, undercoating, grinding, welding, and other jobs. A helpful 3M Automotive Respirators Selection Chart appears on page 8 of the online catalog.

The 3M OV cartridges contain a layer of activated carbon used to reduce exposure to certain organic vapors, like those produced during painting or cleaning of spray equipment. A vapor is a substance that evaporates from a liquid or solid, such as paint thinner. The activated carbon absorbs certain organic vapors as they pass through the filter, trapping the vapors until the cartridge reaches its filtering capacity. 3M uses various filters to reduce exposure to airborne particles.

Although the products are sorted according to purpose (paint spray; grinding, sanding, and buffing; welding; and so forth), we contacted 3M for some general guidelines on choosing the right respirator for a specific job.

3M reps told us that, in addition to using respiratory products, other efforts to help reduce exposure to airborne contaminants are important. Adequate ventilation and proper chemical handling, mixing, and application methods can greatly reduce the amount of airborne contaminants generated. These controls should be implemented before using respirators, or in addition to using respiratory products.

After that, the first and most important step when selecting the proper respirator for DIY/hobby use is to identify whether you are being exposed to particles, gases or vapors, or both. The product label and product material safety data sheet (MSDS) will list all hazardous chemicals present, as required by law. The MSDS may also include recommendations for respirator use. Always read product warnings very carefully and call the product manufacturer if you have questions.

The do-it-yourself, non-professional hobbyist must also realize and understand that the use of respirators will only reduce the exposure to airborne contaminants; it will never completely eliminate exposure. Their effectiveness is dependant upon many factors, including the selection of the proper cartridge or filter, filter efficiency, the fit of the facepiece, and the airborne contaminant concentrations. It is also extremely important to read, understand, and follow the user instructions included with each respirator facepiece, cartridge, and filter for do-it-yourself, non-professional hobbyist applications.

When selecting respiratory protection for occupational use, employers are required to evaluate the levels of airborne contaminants. It's unlikely that a hobbyist would be equipped to monitor their exposure levels. Using sight, taste, or smell to determine hazard levels is unreliable, since many hazardous airborne contaminants cannot be seen, tasted, or smelled. 3M strongly recommends that the application of many types of paints be left to professionals. One example is two-part urethane paints, which contain un-reacted isocyanates and should not be applied by the do-it-yourself, non-professional hobbyist.

Outside Air
Many professionals and hobbyists use supplied-air systems, which feed air directly into the respirator mask or hood. Some systems use shop air from the compressor, which works well as long as the a hobbyist has a compressor with the adequate capacity to provide air to the spray gun and to the mask, as well as suitable filter systems to remove oil mist and dirt from the supplied air. We talked to Axis Products and to SAS Safety Corporation, two manufacturers of supplied-air systems that, instead of filtering the air inside the shop, use an intake pump located in a fresh-air area (outside of the paint booth or garage) to feed clean outside air to the respirator through a hose. Both of these companies offer multiple-line systems for more than one person to use at once. Axis Products' Pro Air line has a two-person Buddy System, and SAS Safety has two-, three-, and four-man systems. Both of these companies offer all systems with your choice of mask: half-mask, full-face mask, or hood.

What Does N95 Mean?
The National Institute for Occupational Safety and Health (NIOSH) is the federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness.

When choosing a respirator for your particular project or activity, consider looking for the NIOSH approval-such as N95, for example-to identify government-approved products. NIOSH certification means the respirator has passed stringent government performance standards, including filtration efficiency testing and gas and vapor capacity testing.

The "N95," "R95," or "P95" designations are government-approval classifications for filters used with particulate respirators. These respirators can be full-face or elastomeric half-mask facepieces. The letter signifies the type of materials appropriate for the respirator. The numeric designation signifies the minimum efficiency, as a percentage, of the filter at removing particles as tested by the government. For example, 95 indicates a minimum filter efficiency of 95 percent. The meanings of the letters are as follows:

*N = Not resistant to oil
*R = Resistant to oil
*P = oil Proof

The N class of filter is appropriate for most common particles, including those generated from sanding and grinding. N-designated filters are the choice for solid or non-oil particulate contaminants. An R- or P-class filter would be the choice for oil mist or particles. 3M reps told us these respirators are only to be used for particles. If there are also exposures to gases or vapors, then an air-purifying respirator with a particulate filter and chemical cartridge should be used.

We discovered a chart on the Internet, titled "Standard for Filter Selection," listing NIOSH general recommendations for respirator cartridges and filters for a variety of applications. The portion of the chart shown below refers to substances related to automotive paint and bodywork.