Abstract: An employee was the west coast sales representative for Arcos Industries and was demonstrating and selling wire feed thermal spray equipment and supplies. Thermal spraying is a process where objects are coated with various metals to provide for corrosion or abrasion resistance, thereby enhancing the equipment's useful life. Canyon Industries, a hydro-electric impeller service company, wanted to test the thermal spray technology. A set of impellers at the Nooksack Falls Hydro-electric project in Glacier Washington was chosen for this test. Impellers within hydro-electric generation facilities are subject to abrasion and degradation from silt and other impurities in the water. The week prior to his death, the employee was involved in this test application. This demonstration at the Nooksack Hydro-Plant was much more extensive and time consuming than any of the normal demonstrations he had done before. The Nooksack Falls Hydro Plant is a diversion plant, where water from the river is channeled from above the power plant, runs through the turbine system, and then back into the river. The power house consists of a generator with a large shaft connected to impellers in two separate housings designed to accommodate up to three impellers (runners) in each. Each housing consisted of a large iron casing approximately five feet in diameter. The impellers consisted of a series of spoon shaped "buckets" approximately 18 inches in diameter attached around a large wheel approximately 4 feet in diameter. The test impeller was in housing Number 1, which had only two of three impellers installed at the time. During the application the metal casing was removed and set in front of the shaft. A wooden scaffold was constructed around the top of the impellers to allow easy access to the upper buckets on the impeller. The employee was performing the testing at the Nooksack Falls Hydro Plant in Glacier WA. He arrived on Monday, September 29, 2003 to arrange the equipment. On Tuesday, September 30, 2003, sand blasting was performed by Canyon Industries. The employee was in the background setting up equipment. On Wednesday, October 1, 2003, the employee applied a base coat all day with two coworkers. The base coat was Arcos Number 888, which consisted primarily of nickel (93) and was applied to both the front and backs of all the buckets (scoops) on the first impeller. Only the fronts were required, but due to a mix up, both the fronts and backs were base coated. This phase of the lasted all day Wednesday and was completed Thursday morning. On Thursday, October 2, 2003, the base coast was finished and a hard top coat was applied. The top hard coating was Arcos Number 1, which contained between 18 and 26 chromium, and was applied to only the fronts of the buckets on the first impeller. This took several hours on Thursday and required two employees. One worker operated the thermal spray gun while another worker held a heat gun over the work. The heat gun was necessary since the impeller buckets were made of case iron which is sensitive to over heating. They could only apply the coating in any particular area for a small amount of time. Thus, both workers were heavily exposed to the process. The employee completed approximately 75 percent of the base coat and approximately 50 percent of the top coat applications. While spraying, the employee was provided with a 3M 8511 respirator, N95, APR and Number 3 Shade glasses. He did not wear shaded full face shields that were provided by Canyon Industries. In addition, the employee had a full beard and wore his N95 respirator incorrectly. He wore the respirator with only one of the straps on his head. Thus, the respirator was completely ineffective. The weld wire used in the base coat contained nickel and aluminum. The weld wire used in the hard coat contained Chromium. All three metals were found in black dust which had settled on the surface of the employee's hat, which was clean at the beginning of the demonstra