This issue is hotly debated currently and is the subject of hundreds of lawsuits nationwide. Welding is a process that has long been considered hazardous because of the potential of eye injury and electrocution. Recently, it has discovered that the fumes can also be a major inhalation problem. A group of scientists has done some very interesting work in characterizing these fumes and the attendant exposures. Mr. Hays has been involved with these investigations for many years. Even though the work is being used in the litigation, it will be presented here. Some of the work represents new applications of existing analytical protocols to the questions of interest.