Abstract: On July 7, 2005, Employee #1, a construction laborer, was working at a power station where his employer had been contracted by a local city utility to construct and rig underground vaults. Employee #1 was using a blowgun consisting of an air line powered by a compressor above the vault, attached to a nozzle that could be secured to the opening of a conduit with an expandable rubber boot assembly. The air line would force a small, double-cone-shaped hard plastic "bird," about the same diameter as the inner diameter of the conduit, down the line to the next vault, which was about 200 yards away. The cone assembly was attached to a nylon tether, which would pop out at the other end; the tether would then be used to pull cable through the conduit. During the construction of the vault at the other end, cement had leaked into one of the 4 in. wide conduits, forming an obstruction out of view of employees and supervisors. When Employee #1 tried to shoot the bird device down that conduit, the obstruction caused back pressure that blew the nozzle assembly off the end of the conduit. The assembly struck Employee #1 on the left side of the head, partially amputating his left ear. A crew with the city utility was working near the site and extracted Employee #1 from the vault. Apparently, the employer had been trained and equipped to complete a confined space rescue, but the city utility employees were able to respond more quickly. Employee #1 was transported by Los Angeles City Fire paramedics to Los Angeles County/USC Medical Center. The employer informed DOSH of the accident within eight hours. The pneumatic tool, which had been manufactured and distributed by Conduit Technologies of Riverside, CA, did not have an operator's manual. Upon inspection, no serial number or model number was readily visible on the unit. A one-page list of operator's instructions, apparently from the manufacturer, did not provide a safe operating pressure for the device. Employee #1 had been wearing personal protective equipment including, but not limited to, a hardhat and safety glasses, and he was experienced in the job being performed. The employer was cited for a violation, general, of T8CCR 3301(c), in relation to use of compressed air.