On April 7, 2000, at 1056 hours, Central Dispatch notified the volunteer fire department and reported a grass fire around a large fuel tank. Responding units included Unit 504 (command vehicle), Engine 502, Engine 505, and one police cruiser. Arriving on the scene, the Chief conducted a size-up and noticed a small grass fire around a fuel tank. The Chief radioed for the other arriving units to pull a handline. The tank was lying on the ground, in an east-west orientation, with the east end of the tank slightly elevated. The grass fire was comprised of burning grass and rubbish located on the north, east, and south sides of the fuel tank. The victim and Fire Fighter #1 were on the north side of the tank and used the 1¾-inch preconnect from Engine 502 to knock down the fire and to cool the tank. Also, two fire fighters on the south side of the tank used the 1¾-inch preconnect from Engine 505 to knock down the fire and cool the tank. A civilian (Civilian #1) approached the Chief and informed him that he wanted to cut a hole in the end of the tank. The Chief acknowledged him and agreed, and Civilian #1 then began using a cutting torch to cut a hole near the threaded opening of the 2-inch fill pipe, while Civilian #2 (a second fatality) stood nearby and watched. Note: The Chief later stated that he did not realize or fully understand the request the civilian was making in regards to the methods the civilian would employ when cutting the hole in the tank. When the cutting began, there was a loud noise (reported as sounding like a jet engine), the tank swelled, and then exploded. The east end of the tank separated at the seam and was blown 114 feet in an easterly direction. The tank turned 180 degrees, with the opened east end of the tank now facing west. At the time of the explosion, the victim was in the direct path of the east end of the tank and was killed instantly. The Chief, Assistant Chief, fire fighters, and a city police officer began administering medical treatment to Civilians #1 and #2 and Fire Fighter #1. Fire Fighter #1 was knocked to the ground and received numerous injuries to his legs. Fire Fighter #1 was transported to a nearby hospital where he received further medical treatment. Civilian #1 was knocked to the ground, receiving severe burns, and was transported to the State's burn treatment center. Civilian #2 (a second fatality) had both legs severed at the knees from the flying debris. He was life-flighted to the regional hospital where he was later pronounced dead as a result of the traumatic amputation of his lower extremities. NIOSH investigators concluded that, to minimize the risk of similar occurrences, fire departments should: 1. ensure that, for fires involving potentially dangerous substances, fire fighters utilize and follow the guidelines set forth in the U.S. Department of Transportation's North American Emergency Response Guidebook; 2. develop, implement, and enforce standard operating procedures (SOPs) that address fire fighter safety regarding emergency operations for hazardous substance releases; and, 3. ensure that emergency response personnel adhere to the procedures outlined in 29 CFR 1910.120(q)2 - Emergency response to hazardous substance releases. Additionally, owners of aboveground storage tanks should: 1. register all tanks, existing or new, with the State Fire Marshal; 2. ensure that aboveground tanks are in compliance with NFPA 30 2-3.6 "Emergency Relief Venting for Fire Exposure for Aboveground Tanks"; and, 3. ensure that unsupervised, isolated aboveground tanks are secured and marked in such a manner as to identify the fire hazards of the tank and its contents to the general public. Additionally, operators conducting welding or cutting should: 1. consider all containers/tanks hazardous unless they have been tested and found safe, cleaned, or rendered inert; and, 2. prohibit welding or cutting operations in the presence of explosive atmospheres.