The missed signals leading up to a blowout with the most fatalities since Macondo resembles that offshore disaster. The investigations by the US Chemical Safety and Hazard Investigation Board (CSB) of the blowout on the Pryor Trust 1-H 9 well and Macondo concluded that both were the result of a failure to maintain the barriers needed to prevent an influx of gas into a well. In both cases, the board found a series of missed signals, misleading tests, and miscalculations that allowed gas to build up in a well unnoticed, leading to a blow-out that could not be stopped by a blowout preventer (BOP). Workers died in both cases—11 at Macondo and five at Pryor Trust. An obvious difference is in the level of notoriety. Macondo is still remembered for the destruction of the Deepwater Horizon and an offshore oil spill that lasted for months. The Pryor Trust well was an onshore gas well in rural Oklahoma where a blowout destroyed a rig in the morning and the fire was put out that afternoon. There was little media coverage. The environmental impact was minimal, and the companies involved, Patterson-UTI Drilling and Red Mountain Energy, are not well known. Still, it provided a stark warning of the risks associated with some widely use drilling practices. “Our investigation found significant lapses in good safety practices at this site. For over 14 hours, there was a dangerous condition building at this well,” said Kristen Kulinowski, interim executive at the CSB, a federal agency that investigates major accidents, in a statement on the report. “When the blowout mud and gas ignited, it created a massive fire on the rig floor. All five of the workers inside the driller’s cabin were effectively trapped because fire blocked the driller’s cabin’s two exit doors,” said Lauren Grim, a CSB investigator who noted there is no guidance to ensure that an emergency evacuation option is present. “The investigation revealed that there are no regulations specifically developed for onshore oil and gas well drilling,” the statement said. It explained that while the Occupational Safety and Health Administration (OSHA) does monitor oil and gas operations under a clause that “protects workers from serious and recognized work-place hazards,” onshore exploration and production (E&P) is exempt from the OSHA process safety management standard. Offshore oil and gas process safety is regulated by the US Bureau of Safety, Environment, and Enforcement. The report said onshore E&P operations should be subject to OSHA’s process safety standard to “addresses the hazards unique to the onshore drilling industry.” The CSB asked the American Petroleum Institute (API) to provide recommendations to fill these gaps.