Federal Report Says Gas Line Was Unmarked Before Fatal Oak Cliff Blast

A preliminary federal investigation indicates the gas line involved in May’s deadly Oak Cliff explosion was unmarked when excavators began survey work on the residential property.

The National Safety Transportation Board released the preliminary report on Wednesday, shedding some light on the May 28 incident that killed three people, injured several others, and destroyed an apartment building at 409 E 9th St.

Media relations personnel for NTSB told CandysDirt.com that the report “reflects an early stage of the investigative process, and no conclusions or determinations regarding probable cause have been made.”

Early reporting on the explosion linked the blast to geotechnical drilling outside The Clyde apartments after records suggested a drill rig operated by Barba Drilling Co. Subcontractors may have struck a natural gas line while working for ECS Limited, an engineering and consulting firm hired to conduct soil testing for a planned redevelopment of the property, as previously reported by CandysDirt.com.

Developer O-SDA Industries is planning to purchase The Clyde and combine it with an adjacent parcel to deliver an 82-unit multifamily project. The company’s president said O-SDA plans on pursuing the acquisition.

“On May 21, 2026, Engineering and Consulting Services Southwest, LLP (ECS) submitted a Texas 811 ticket. Texas 811 is a centralized system in which excavators are legally required to call 811 at least 2 business days before beginning a digging project to notify the gas company. Although the locations of some of the assets had been marked by painting and flagging, the location of this gas line had not been identified and marked,” the preliminary report reads.

According to NTSB’s preliminary timeline, Dallas Fire-Rescue responded to a gas leak call at 12:49 p.m. and notified Atmos Energy two minutes later after learning a gas line had been cut. The apartment building was “destroyed in a natural gas-fueled explosion and subsequent fire” around 1:15 p.m., before Atmos crews arrived several minutes later. Crews isolated the damaged line over the course of about half an hour, stopping the flow of natural gas while firefighters battled the blaze.

Roughly 100 firefighters responded to the scene, and a plume of smoke could be seen from as far as Tarrant County. On June 17, local officials recognized Dallas Fire-Rescue at a city council meeting for the first responders’ heroic efforts that day.

“[They] entered into an extremely dangerous and unstable environment to search for survivors, extinguish fires, and secure the area,” said City Manager Kimberly Tolbert. “Their response required tremendous bravery, technical expertise, and an unwavering dedication under difficult conditions.”

She went on to also celebrate the work of personnel from Dallas Water Utilities, Transportation & Public Works, the Office of Emergency Management & Crisis Response, and the Office of Homeless Solutions & Community Empowerment.

“While each department had a different role, they shared a common purpose: serving the people of Dallas when they needed us the most,” Tolbert said. “The response to this tragedy demonstrated what is possible when dedicated public servants come together with a shared commitment to protecting lives and supporting our community. Their bravery and professionalism were displayed throughout that entire situation.”

At least five people were treated at local hospitals in the aftermath, including one who was seriously injured. Sylvia Collins, a longtime Oak Cliff community activist and precinct chair for the Dallas County Democratic Party, died in the blast and ensuing fire, as did Marisol Perez and her 18-month-old son Erick.

“Our hearts remain with the families who lost loved ones, those who were injured, and every resident whose life was turned upside down by this tragedy,” said Council Member Chad West (District 1), who represents the area. “Three people, including an infant, lost their lives, and many others lost their homes and their belongings. In the face of unimaginable loss, we also witnessed the very best of Oak Cliff and Dallas.”

Local businesses and residents raised money for survivors and the families of those who were killed, while the city engaged in emergency housing support for the dozens of people who lived at The Clyde.

The NTSB said final reports can take 12-24 months to finalize, with Wednesday’s findings subject to change based on additional evidence.