 Almost everything that's manufactured, built or repaired goes through a finishing process. By cleaning, sealing and painting, products are made ready for purchase. There are two reasons for using finishes. First, it looks better. And second, it protects the product from wear by its user, or by time in the elements. One of the most common finishing processes is spray painting. Developed along with the mass production concept, it has even become popular in the consumer market. Two of its chief attributes are speed and efficiency. This system paints 975 pieces an hour. Another benefit is the even coating spray painting puts over the surface of the object, often to tolerances of one mil or less. As manufacturers have looked for ways to improve production processes to reduce costs and improve products, spray painting technology has rapidly advanced to help fill their needs. Now there are a number of spray paint equipment options for even a modest sized operation. New coatings have been developed too. A change in processor coating is easier because of these options. Changes can be made for a range of reasons. Among them, greater product protection. There's another protection objective that can't be ignored whenever decisions about finishing processes are being made. Painters. The health hazards posed by their jobs are real. Every finishing process has its advantages and disadvantages. But you should make choices about finishing operations with a dual protection objective. What's best suited to your products and your painters. When spray painting, workers can be exposed to highly volatile and toxic materials. Paint coatings have three major types of components. Pigments, which give them their color. Binders, which cement the pigment particles to each other and to the product. And solvents, which give the paint a consistency that will spray easily. Within each group are a number of substances recognized as health hazards. Many pigments are virtually harmless. Titanium dioxide, a pigment in wide use in paints, is considered to be a nuisance dust. Some pigments are more hazardous. Although prohibited in architectural consumer uses, various lead compounds are still being used as industrial pigments. And the hazard of chronic lead poisoning is still prevalent. Workers with this condition may suffer weakness, weight loss, insomnia, anemia, and pains in their muscles and joints. Chromium compounds are found in some paints. Some forms of it may cause cancer. Some coatings use organic isocyanates as curing agents. They can be irritants to the eye and the respiratory system and may result in sensitization of the worker. Other known irritants and sensitizers also find use in coatings. Petroleum distillates are the most common paint solvents. Other examples are ketones, esters, glycols, toluene, and xylene. In general, these chemicals irritate the eyes, skin, and respiratory tract. They can be particularly dangerous because many of them are colorless and look like water. At high concentrations, some solvents can cause headaches, drowsiness, and unconsciousness. Repeated contact with the skin can cause prolonged and severe dermatitis. This is often a problem where solvents are used for cleanup. When spraying, there's always paint that misses or bounces off the target. This overspray can cause exposure to toxic paint components. Although more recent process innovations such as electrostatic and airless equipment have greatly reduced overspray, these techniques are not suitable for all situations. Compressed air operations, where often as much paint is wasted as is applied to the product, will be common for a long time to come. The economics of the problem are obvious. Buying twice as much paint as necessary takes money. Providing ways to contain and dispose of that extra paint after it misses the surface it was intended to coat, take money and time. The human costs are also potentially great. Coatings that spray painters apply can enter their bodies through the nose, mouth, and skin. From there, they can enter the respiratory system, the digestive system, and the bloodstream. Protecting your workers from overspray may involve respirators, gloves, training programs, even medical exams. These approaches take time, money, and sometimes worker health is still jeopardized. Controlling overspray is doubly important. Solving worker exposure problems has implications for supervisors, workers, managers, engineers, and suppliers. Because there are so many coatings and types of spray equipment in use, it's difficult to make specific recommendations in this program. Instead, we'll cover basic avenues of approach to control of health hazards. If you're using coatings that contain hazardous substances, first consider switching to safer ones. In recent years, the number of different paint formulations available has increased dramatically. There may be alternatives to what you are using that are just as good, maybe better. All coating ingredients are used because of specific properties, and there are trade-offs in any switch. Some chromate substitutes sacrifice color, match, cost, and durability. But the automobile and shipbuilding industries are currently interested in metal primers that contain metallic zinc dust in place of zinc chromate. It protects metal by galvanizing it rather than merely inhibiting rust. And unlike zinc chromate, it is of low toxicity. Powder coatings have been developed in part to eliminate the use of hazardous solvents. They require the use of special equipment, but they have low energy consumption and will build a heavy coating in a single pass. The appliance industry is currently the heaviest user of powder coatings. Water has been successfully used in some situations to replace many of the organic solvents. Water-borne coatings, as they're called, are much less hazardous to painters. There are no completely safe coatings. Selection of one or another is complicated, and you may need help with that decision. Paint suppliers are one resource. The National Paint and Coatings Association in Washington, D.C. can give you general information about coatings and their health effects. But the best resource for specific recommendations may be an industrial hygienist or other health professional in your area. So far, we've covered changing the content of the coating material to meet our double protection objective. Actually, cutting the amount of overspray in an operation will probably require an equipment change. Where compressed air delivery systems used to be the rule, now airless heated paint and electrostatic systems are able to significantly reduce the overspray problem. Every system has its pros and cons. Compressed air systems are excellent for frequent color changes, will coat almost any shape, will apply water-borne paints, and can be used on automatic gun movers. But they waste large amounts of paint. Often, they require more energy to run the bigger exhaust systems necessitated by the overspray. Airless guns use hydraulic pressure to force the paint through a small opening and into the air. The process can be compared to a garden hose nozzle that atomizes water by forcing it through a small opening under pressure. Airless sprays are often heated as well. Overspray is greatly reduced over compressed air delivery. Heavier coats can be developed without runs or sags. Hot airless may produce a higher gloss, too. Airless guns may clog a bit easier because of the smaller opening used. The systems are more expensive, have a more limited pattern and flow adjustment, and have some overlapping difficulties. There is danger of serious injury to painters who misuse this equipment. Injection of paint under the skin can have serious consequences. Electrostatic guns electrically charge the paint as it leaves the gun, which attracts it to the grounded object to be painted. This substantially reduces overspray and possibly reduces ventilation requirements. Electrostatic application provides excellent wraparound and coating of sharp edges. However, it may not coat recessed areas or other null points on the object. Suppliers in their trade group, the National Spray Equipment Manufacturers Association, can help you select the system to best protect your painters and your products. If you can't eliminate or alter the overspray, you can keep it out of the painter's breathing zone and the rest of the area with proper ventilation. This is most often done with spray booths. Whether small booths or large ones, they all work by directing cleaner air past the worker toward the product and into a collection point or exhaust hood. Larger products may require a top-to-bottom airflow to work effectively. Designers of good ventilation systems must consider a number of complex variables, such as air velocity, air cleaning techniques, and degree of enclosure of a space. It's work for a qualified engineer. Another way to reduce worker exposure is to isolate him from the process. This can be done by automating the system, which is expensive to start but cheap to operate, or by personal protective equipment for the painter. A respirator, gloves, overalls, and hat provides a protective coating for the painter and isolates him or her from the overspray. Supervisors can help instill good work practices that will further reduce exposure. One of the most common application faults is paint sprayed with too much pressure. Another is allowing the workpiece to come between the source of fresh air and the painter. The gun is then pushing paint against the airflow, increasing overspray. Painters often work in pairs. A common error is spraying from opposite sides of the product into each other's faces. Training is the key to good work practices. With the right knowledge, a painter will go a long way toward providing his or her own protection. In recognition of this, the National Fire Protection Association Committee on Finishing Processes recently adopted language in their code, Mandating Training for Spray Painters. They specify that training beyond the potential safety and health hazards, operation maintenance and emergency procedures, and the importance of awareness while working. Managers should enforce employee use of that kind of training. To review, control of the health problems associated with overspray and finishing operations can be done by substitution of new coatings or processes, proper ventilation equipment, isolation of the painter, and good work practices. If you want more information on these topics, you can obtain a copy of the NIOSH Technical Report, an evaluation of engineering control technology for spray painting at this address. Too often, safety and health efforts are viewed as being at cross purposes with production efficiency and quality. But in the finishing department, it's only a matter of doing two things at once. The same systems that make your products look good and protect them in use should protect your painters. When you consider altering your finishing department, have dual protection in mind.