You are absolutely doing the right thing in trying to find out the facts about welding fume, whether welding aluminum or any other material. The aluminum alloys produce much more visible welding fume (the white smoke that you see) than many other materials. This is especially true in GMAW. It is not as apparent when performing gas tungsten arc welding (GTAW) on aluminum. This happens because in GMAW we are transferring metal across the arc. In doing this, a good bit of material evaporates and forms the visible fume. In GTAW the filler wire doesn’t get as hot, so much less material evaporates and creates fume. I have some good news for you. Although the process produces a lot of white fume, it consists almost entirely of magnesium oxide and aluminum oxide, which are considered to be merely lung irritants. I won’t kid you, both substances will irritate your lungs, so you shouldn’t breathe them if you can avoid it. However, they don’t contain anything that would adversely affect your health long term, unlike fume produced when welding other materials. There is no beryllium in aluminum filler welds, nor is there any manganese, chromium, or nickel. In fact, the fume given off aluminum welding has been rather well-researched. Four different comprehensive studies were conducted under the sponsorship of the Aluminum Association in Arlington, Va. Any or all of them are available for purchase if you are interested. There is one aspect of weld fume that I haven’t discussed, and that is the formation of ozone gas (O3). You are all familiar with this gas because it produces the smell in the air after a thunderstorm. Because of the high currents and pure argon shielding gas used in welding aluminum, large amounts of ozone can be produced. Ozone is considered to be a lung irritant, so much so that federal standards limit how much ozone can be present in the air. It may be necessary to install ventilation systems to remove ozone from the welding area, especially if you weld in an area that isn’t well-ventilated. This article is by no means comprehensive and was not meant to be. I’ve only attempted to address items specifically related to fume generated when welding aluminum here. I have not discussed any other aspect of welding fume or protecting yourself from it. Make sure that you are familiar with the required safety precautions and are protecting yourself properly.