1956 — Aug 13, Liquefied Petroleum Gas Explosion, Lariat Café, Monticello, UT — 15

— 15 Jones. “Open-Ended Gas Line Causes 15 Deaths.” NFPA Quarterly, 50/2, Oct 1956, 91.
— 15 NFPA. “LP-Gas Fires and Explosions.” NFPA Quarterly, Vol. 55, No. 2, Oct 1961, p. 170.
— 15 National Fire Protection Assoc. Spreadsheet on Large Loss of Life Fires (as of Feb 2003).

Narrative Information

Jones: “The LP-Gas 1,000-gallon aboveground tank…supplied the Lariat Café…and the apartment house…When the gas service to the cafe was shifted to natural gas, the line from the LP-Gas tank was cut (but not plugged) and the valve was shut off at the tank. Subsequently someone opened the tank valve to secure fuel for a water heater in the apart¬ment and gas leaked into the cafe basement through the cut line. [Photo caption, p. 91.]

“During the dinner hour on Monday evening, August 13, a tragic explosion destroyed the Lariat Cafe in Monticello, San Juan County, Utah, killing 15 per¬sons and injuring 24. This explosion was reported to have been caused by ignition of an accumulation of liquefied petroleum gas in the basement of the one-story concrete block café.

“Observers stated that the one-story concrete block cafe building burst just like an egg shell. The building walls were blown out and the flooring lifted from the joists. There was no subsequent fire. Over 50 persons were reported to have been in the cafe. Deaths and injuries were due to concus¬sions, being struck by flying debris, or crushed by collapsing portions of the building.

“Rescue operations were quickly or¬ganized immediately following the blast. All the nearby communities in Utah and southwestern Colorado promptly sent help to the disaster scene and the injured were cared for in emer¬gency quarters set up within the town. Hospital facilities in the town of Monticello and other nearby commun¬ities were used to the fullest extent. Excellent cooperation was prevalent in this whole area with all emergency services operating very effectively.

“Preliminary investigations revealed that the LP-Gas service piping in the cafe’s basement was not properly capped or plugged on the previous day after the gas service had been shifted from LP- Gas to natural gas.

“Monticello, a small community in southeastern Utah, was the first com¬munity in Utah to receive natural gas from the Pacific Northwest Pipe Line Company. A local natural gas utility company, Utah Public Service Com¬pany, was recently organized to provide natural gas service to communities in the state. Gas distribution, lines had been installed throughout Monticello in accordance with the American Stand¬ard Code for Gas Transmission and Distribution Piping. Arrangements were made with the utility to change over to the natural gas service in the cafe on Sunday, the day preceding the explosion, so as not to interfere with business operations. As indicated previ¬ously, the cafe used liquefied petroleum gas fuel for cooking. The LP-Gas was supplied to the cafe and to an adjacent apartment house from an outside 1,000-gallon aboveground tank equipped with a regulator. Apparently workmen shut off the LP-Gas system by closing the valve at the tank and then cut, but did not plug, the LP-Gas low pressure gas service line (copper tubing) in the base¬ment of the cafe.

“Reports indicate that the new natural gas piping in the building was installed in accordance with NFPA Standard No. 54. Piping was tested for leaks prior to connection to the gas meter in a standard manner and, since no leaks appeared, the natural gas system was placed in service. Workmen adjusted the burners and pilots and departed. Unfortunately, the LP-Gas supply line was left open-ended and not securely closed gas-tight with a plug or cap in conformance with Paragraph 3(m) of NFPA Standard No. 52.1.

Explanation of Explosion

“Preliminary investigation disclosed that the low pressure LP-Gas piping coming from the 1,000 gallon LP-Gas tank contained a tee. This tee was provided with a valve on each branch line. One branch of this line supplied the cafe, the other went to the nearby apartment house. Evidently, the apart¬ment house water was heated by an LP-Gas fueled appliance. Since workmen had closed the main LP-Gas supply line, occupants of the apartment house sud¬denly discovered they were without hot water, and some unknown person turned on the LP-Gas supply at the tank to remedy this situation. This permitted the LP-Gas to enter the cafe’s basement through the open-ended tubing. Igni¬tion of escaping LP-Gas and air mixture was probably caused by a pilot or oper¬ating burner of the gas-fired equipment in the kitchen of the cafe. Testimony in the investigation has verified the fact that the LP-Gas system was shut off at the tank. However, immediately following the explosion, it was determined that the LP-Gas tank valve was in the open position and it was closed by someone at the scene following the explosion.

“Further investigation proceedings are continuing regarding the explosion by local authorities as well as the Public Service Commission and. the Industrial Commission of Utah in an effort; to determine further pertinent information.” (Jones, Clark F. “Open-Ended Gas Line Causes 15 Deaths.” Quarterly of the National Fire Protection Association, Vol. 50, No, 2, Oct 1956, 91-92.)

National Fire Protection Association: “Monticello, Utah, Aug. 13, 1956, 15 killed.

“Fifteen people in the 1-story concrete block building housing a restaurant were killed when an LP-Gas explosion that originated in the basement demolished the building. On the previous day a change¬over had been made at the restaurant from LP-Gas to natural gas. After completing the natural gas installation, a workman shut off the LP-Gas supply by closing a valve at the 1,000-gallon outdoor tank. He then cut the LP-Gas supply line in the basement of the restaurant, neglecting to cap or plug the line.

“The outdoor LP-Gas tank also supplied fuel for a gas hot water heater in a nearby apartment building. When the workman closed the valve at the tank, he, therefore (unknowingly), also shut off the supply to the hot water heater in the apartment. The explosion occurred after someone opened the valve at the tank, thereby allowing LP-Gas to escape into the restaurant basement from the cut pipe.

“Investigation revealed that there was a tee on the low pressure side of the tank pressure regulator, one leg of which went to the restaurant, the other to the apartment, and that both legs were provided with manual valves. Had the valve on the leg to the restaurant been closed by the workman in¬stead of the tank valve, the explosion would not have occurred.” (National Fire Protection Association. “LP-Gas Fires and Explosions.” Quarterly of the National Fire Protection Association, Vol. 55, No. 2, Oct 1961, p. 170.)

Sources

Jones, Clark F. “Fatal LP-Gas Tank Truck Fire.” Quarterly of the National Fire Protection Association, Vol. 53, No. 2, Oct 1959, pp. 89-97.

National Fire Protection Association. “LP-Gas Fires and Explosions.” Quarterly of the National Fire Protection Association, Vol. 55, No. 2, Oct 1961, pp. 170-212.

National Fire Protection Association. Spreadsheet on Large Loss of Life Fires (as of Feb 2003). (Email attachment to B. W. Blanchard from Jacob Ratliff, NFPA Archivist/Taxonomy Librarian, 7-8-2013.)