Abstract: At approximately 11:45 p.m. on October 13, 1990, Employee #1, a mechanical supervisor, was working on a well water supply system for a winery. His employer had been engaged to install the equipment. Water was spraying from a pressure relief valve on the well line, but no water was available from the tank. Employee #1 was asked to supply water to the winery from one of two newly installed 100,000 gallon storage tanks on site. Employee #1 began work on a 220 gallon tank, not the larger tanks as had been requested. During the effort to direct water from the functional deep water well, Employee #1 attempted to force water into the 220 gallon galvanized cold water pressure tank by placing a threaded 1/2 in. plug into the vent hole. The tank exploded, killing Employee #1.