Abstract: Two power line workers had finished testing a deenergized distribution transformer. The day before, a vehicle had struck a utility pole, tripping the upper and lower protective devices on the transformer. The 110-kilovolt transformer was deenergized and locked out. The employees had conducted numerous tests and were satisfied that the installation was safe. However, upon being reenergized, the transformer failed. The corner seam on one side ruptured, and flames shot out of the opening. The two employees, who were about 60 feet from the transformer, sustained burns. (One other employee was knocked through the cab of a truck, but apparently was uninjured.) One of the injured employees was treated at a hospital and released. The other injured worker was hospitalized.