The accident occurred at approximately 9:00 p.m., when six individuals aged 18 to 32 were socializing at the rural site, which normally was unmanned. The site, which had four petroleum storage tanks and two brine storage tanks, was operated on private land by two production firms, Three MG Family Inc. and Enterprise Energy, who leased the mineral rights. A third company, ScissorTail Energy, operated a gas metering and collection system connected to the production equipment.
The blast occurred about 10 minutes after the group arrived at the site. Witnesses stated that they were drawn to the site when they saw the open gate while driving along a public roadway. Witnesses further stated that oil sites were a common gathering place for local residents and that they largely were unfamiliar with the hazards.
Cigarette was Possible Cause
Based on witness interviews, CSB investigators determined that a lit cigarette or lighter was the likely ignition source for the explosion, which happened as the 21-year-old male who later died was peering into the hatch on top of one of the tanks. That tank contained what was later described as approximately 160 barrels of light crude oil. The resulting explosion and fire engulfed the victim and caused a second explosion in an interconnected tank. A fire burned for more than 3 hours until it could be extinguished by several responding fire departments.
“The catwalk leading to the top of the tank was unsecured and readily accessible,” said CSB Investigator Vidisha Parasram. “The tank hatches had no mechanism which would permit them to be secured or locked. No fire or explosion warning signs or other warning signage was visible anywhere on the site following the accident.”
Parasram said CSB would continue to study whether any signage could have been destroyed in the fire, but that even the undamaged portions of the facility and the entrance gates had no posted warnings. Eyewitnesses said they saw no signs on the night of the accident or during previous visits to the site.
The site entrance was protected only by an unmarked gate which multiple witnesses described as being wide open on the night of April 14, and generally open and unlocked at other times. The site had no fencing or other protective measures that would keep members of the public safe from hazards.
“Following this accident, our investigative team was able to observe a number of other oil and gas production sites in the area. The vast majority were unsecured and had no warning signs,” said CSB Investigations Supervisor Don Holmstrom. “Oil and gas sites that lack security measures and warning signs are an accident waiting to happen.”
State officials told CSB that Oklahoma has approximately 257,000 active and unplugged oil and gas production sites; Oklahoma requires fencing and warning signs only at sites that have toxic hydrogen sulfide gas hazards, according to state officials.
Counting the April 14 accident, CSB has identified a total of seven oil site explosions and fires in Oklahoma since 1990 that killed or injured members of the public, the highest total for any state. Four of these accidents caused multiple fatalities.
“The CSB is concerned about these ongoing accidents across the country that are needlessly taking the lives of young people,” said CSB Board Member William Wark. “To me, it is self-evident that hazardous oil and gas sites should be secured against unauthorized entry and posted with extensive and specific warning signs. And we need to educate teenagers and young adults to stay away from these sites – they are dangerous.”
The day prior to the explosion, the CSB board issued a statement “urging oil and gas production companies to ensure that they provide adequate security and warning signage around sites that have tank fire or explosion hazards; and further urging state legislatures, local governments, and regulators to review rules governing oil and gas tank sites to ensure they require adequate barriers, security measures, and warning signs.”
