Dust is small particles of a material. There are dusts you can see in the air; these can be breathed in, and because the particles are fairly large, they end up in the upper portions of the lungs. Some can be cleared from the body by its natural mucus where it is bound up, and brought up into the esophagus.
From there it is swallowed and so exposes the stomach tissue to whatever chemical was ingested. Jewelry polishers may have elevated rates of stomach cancer as a result of this. With dust in the air, however, it is the smaller, invisible particles that are the most dangerous, and these stay in your lungs.
While the body’s protective mechanisms remove some dusts, others, especially fibrous ones like asbestos, cotton and silica, are stored between the air sacs of the lungs. That is, you breathe them in and they will never escape again; they do not leave your body. Once there, they cause scarring, thickening of tissues, later stressing the heart as a result of it being more work to breathe. If enough particles accumulate, they affect your breathing.
The finer ordinary dust particles, ones you can barely see, and many you can’t see at all with the naked eye, are the worst for you. These particles, often smaller than 10 microns, enter the lungs, go far deeper into their recesses and can result in chronic damage. Many dusts and even metal particles in fumes are this tiny. Because they are so small, they float in the air for hours and merely moving about lifts the settled ones back up into the air for you to breathe in later. When they are this small they are easily bound up and stay put in your lungs or may even be absorbed through the lungs directly into your blood stream (if smaller than 1 micron). Mists and fumes, as well as being a hazard to breathe in, can dry and then form minute dusts in the air as well (Wallers 14, 15). Note that the eye can only perceive dust particles 50-100 microns across, while the most dangerous sizes are those 5 microns or smaller-so small they don’t even show up under an optical microscope. Wherever you can see dust in the air you can be sure that those smaller particles are there too (Kinnersly 106).
Choose the least dust-producing materials, techniques and processes possible. Use local ventilation that takes the dust away from where you are producing it, and removes it safely from your workplace.
I had several people write to me saying that they tried to wear a mask while working in the shop, but they found their safety glasses fogged up or there were other troubles. They then wear face shields instead, but this does not prevent breathing of dusts. Basically, you shouldn’t be working in a way that creates dusts. Use wet clean-up methods (damp mop, for instance) and wipe down at the end of the work day so you don’t raise dusts into the air before starting to work in a space. Vacuuming can boost those small dust particles into the air, and, if you use a vacuum, consider buying one that traps all particles down to half a micron or so. Wet vacuums, too, if not a particularly expensive type, can contribute to the dust in a space (Waller 15).
Be aware of the things you do that generate dusts; for jewelers this usually means using abrasive procedures (sanding, grinding etc.-including flexible shaft use), using powdered materials like cristobalite in casting investment (really hazardous), quenching flasks after casting (even more dangerous), and polishing. Keep your polishing filters clean, make sure the local ventilation is good for polishing dusts; not only is there the concern about larger particles being swallowed and thus exposing you to ingestion of the compound and its greasy binder, but there are some serious questions about using certain compounds, such as tripoli, which contains non-crystalline silica and is lumped into the high-level cristobalite hazard class by some writers (Spandorfer et al 224). Tripoli contains diatomite, a kind of silica that can cause a rapidly progressing silicosis (Stellman and Daum 169). Other writers say that non-crystalline silica isn’t really in a dangerous form unless it has been heated (Waldron 105) when up to 60% of it can be cristobolite (Tver and Anderson 80).
Unfortunately much of the materials that are used as abrasives have been heated. The binder in the tripoli compounds as supplied would seem to me to keep some of the silicosis hazard down because it binds much of the abrasive into a paste, but you should, I think, make sure that your filters are working, and that your dust collection system is good if you are using tripoli. If switching to another compound, make sure it does not have worse hazards to it in some manner. Lapidary workers have to be very careful of dusts they produce, particularly in production situations. There are clear cases of Jade workers getting silicosis in as little as 5 – 10 years. There is also some evidence that silica exposure can lead to kidney failure (Ng et al 761-4).
Silica has been replaced in many industry applications since the early 20th century, examples being artificial abrasive replacing silica in grinding wheels, and replacing sand with corundum, glass beads or silicon carbide in abrasive blasting (Waldron 105).
Consider the kind of material you are abrading, sifting, transferring, and what the implications of turning it into a dust are. Some woods, shells and other materials can be extremely toxic when made into dusts and breathed or touched. Asthma-causing materials include pine resin, iroko, mahogany, western red cedar woods, nickel, platinum salts, animal and insect proteins and more (Waldron 95).
Copper dust can damage the eyes, causing “conjunctivitis and discoloration and ulcers of the cornea” (Rossol 140), and may irritate the skin. Nickel dust is allergenic and affects the skin, eyes and mucous membranes (Rossol 143). Other metal dusts can be a problem.
Running your finger over a ledge in your shop and looking at the color of the dust can be a tip-off as to whether you have a problem with the type of material the dust is made of. If it is gray like ordinary household dust it is not too bad, if it is white or cream then you may be dealing with chemical-containing dust from procedures, if deep black it may be from oily sprays or a defective heating system (Kinnersly 106).
So, don’t have dusts around if you can help it. If you have to create them, store the material properly, damp-clean frequently, segregate dust producing procedures from the rest of your shop, and use local exhaust ventilation or work wet.
If possible, work wet so that particles cannot become dust in the air. There are wet belt sanders available now for working metals (and other materials) that can do a great job (they run cold so you can hold a piece onto them without it heating up in your fingers), and they keep a lot of dust out of the air. When working with silicon carbide separating discs, I use a beeswax lubricant which binds most dust into a paste and thus keeps it out of the air as well. I’ve seen a student apply toxic and irritant cupric nitrate solution to an object for a patination, then sand it off the high points, dry, getting it onto her skin, eyes, hair and breathing it in, getting sick as a result. If she had thought of the surface as a chemical instead of just a “green color,” she might have been more careful, and wet-sanded under cool, running water in the sink, using gloves, to have kept the dust away.
D.X. Ross, an enamelist friend of mine, had her workshop set up so that she did almost no dust-producing activities. She avoided polishing by using hand-burnishing and textured surfaces. She did her sanding using wet/dry paper in trays under a little water. A block of boat Styrofoam was cut to shape and used to press the metal part onto the sandpaper while she sanded. She would set up for soldering on a tray and take it outside to solder.
One of the big sources of hazardous dust is investing for casting. Investment contains 40% to 60% cristobalite, a form of quartz which is many times more likely to cause silicosis than standard quartz is. It is therefore very important to be careful when mixing investment, quenching a flask and removing investment. Local ventilation sucking from where you are working is necessary. When I started insisting on this at our school, after a week we discovered a crust of investment a millimeter or so thick on the mesh over the suction slits. This was without seeing any dust in the air while investing and remembering that the worst particles are the ones you cannot see. We use proper respirators and the local ventilation now. There are recorded cases of silicosis from investing where the worker was only exposed to the material for a year or so. Damp-mop and wipe your studio and investing area rather than vacuuming or sweeping.
Metal sculptors, blacksmiths and people who do larger work (which sometimes jewelers do as well) may use dust-generating procedures, often while finishing. Several metal artists working on a larger scale have suggested their favorite approaches to this problem. Steve R. likes to use a Raycal “Breathe Easy”® with a turbo unit which feeds air into a face shield to keep dust away from the nose and mouth (Steve R. Artmetal list, 4/10/97, “metal dust in the eyes”). Casey Warner, who sands, and does plasma cutting etc. likes the 3M 6000 series mask. It allows him to do all sanding, cutting and welding operations-he says it doesn’t fog up his safety glasses (Casey Warner, Artmetal list, 4/10/97, “Re: metal dust in the eyes”). So, if you have to do work that involves generating dusts and fumes, talk to your safety supply company’s technical staff, find other people working safely with the same procedures you plan on using in order to find good role models, cross-check all information with at least three safety supply sources and then work in a cleanable environment that is separate from your regular workspace, use work clothing, clean religiously and so on.
If you generate dusts or fumes and are exposed to chemicals as a result of your working methods, take full responsibility for what you are doing.
Fumes are small particles of a material, often from metals that have been melted. These may be very tiny and can be breathed in to the lungs. Metal fume fever is a real hazard with molten metals. It has numerous names, the nastiest of which is “the smothers.” Metal fume fever can be caused by zinc, copper, magnesium, aluminum, copper, antimony, cadmium, iron and silver. The particles are so small (0.01-0.5 microns) that they stay in the air a long time. Because they are so tiny they go deeper into your lungs and can then dissolve more easily within your body (Rossol 31). Manganese, nickel and tin may also cause metal fume fever (Tver and Anderson 126). I have known a number of people to experience metal fume fever, from zinc while casting or reticulating brass and once from copper, because they did not use adequate ventilation. Casting brass is a particular culprit, because ventilation is frequently a hood type above a casting machine and the fumes are then drawn past the worker’s face on their way out.
So, don’t cast brasses unless you can help it, use very good ventilation when melting or reticulating metals and if you must do it, use the correct respirator. The onset of metal fume fever is characterized by a sudden thirst and metallic taste in the mouth. Four to nine hours may pass before other symptoms develop which include “rigors, high fever, muscular aches and pains, headaches, and a feeling of generalized weakness” (Tver and Anderson 126). Nausea, dizziness and fluid loss through diarrhea and frequent urination are also likely (Tver and Anderson 191). It is also possible that casting brass or bronze may release trace amounts of beryllium, arsenic (both of which are carcinogens) or antimony. (Qualley 91). Be wary of reclaimed metals and strange metals from a scrap yard; some coppers contain beryllium, for example.