Abstract: On April 12, 2010, Employee #1, a process attendant to the Preheat Tower at a cement company in Cupertino, CA, was clearing an obstruction (plug-up) in the system so that the flow of material (45 micron blended limestone) could resume. Employee #1 was directed to blow down Cyclone Number 8 with valves that flush the area with air and discharge an air cannon. He was then asked to verify the effects by checking a port, a 6 in. pipe that allowed access to the material flow. After opening the port, Employee #1 was exposed to hot alkaline material. He suffered physical and chemical burns to the back of his neck and ears. He was hospitalized for more than 24 hrs at the Santa Clara Valley Burn Center, suffering from burns and scalding. Employee #1 was not wearing personal protective equipment provided on the site.