​​​This information is preliminary and subject to change.

​​On May 28, 2024, about 2:44 p.m. local time, a natural gas–fueled explosion occurred at the Realty Tower Building in Youngstown, Ohio, causing 1 fatality and 9 injuries that required hospitalization.[1] The explosion also caused significant structural damage to the 13-story building, which contained a bank, offices, and residences. Weather conditions at the time of the accident were 70°F with 14-mph winds and no precipitation. Damage estimates were still being determined at the time of report publication.

Just before the accident, a four-person scrap-removal crew, engaged by contractor GreenHeart Companies LLC (GreenHeart), were working in a basement area located just northeast of the building, underneath the sidewalk.[2] (See figure.) GreenHeart was contracted by the City of Youngstown to remove and relocate utilities in preparation for a city road improvement project and, at the time of the accident, the scrap-removal crew was removing old utilities and other items from the basement area.

​In interviews with the National Transportation Safety Board (NTSB), a member of the scrap-removal crew and the GreenHeart site supervisor indicated they did not have any knowledge that the gas service pipelines in the Realty Tower Building basement area were in service, transporting natural gas. The crewmember stated he used a reciprocating saw to cut into one of the pipes he had been told was “dead,” or not transporting gas, but partway through the process, he heard a loud whistling sound and felt gas blowing into his face from the cut pipe. The crew immediately exited the basement area and called 9-1-1 to report the gas leak. At 2:39 p.m., as they exited, a crewmember pulled the fire alarm on the first floor to alert residents and workers in the building. Another crewmember notified bank employees on the first floor about the gas leak.

The Youngstown Fire Department received reports of a gas odor from the public in the minutes before the explosion. Emergency response teams from the Youngstown Fire Department, Boardman Fire Rescue District, Mahoning County Sheriff’s Office, Youngstown Police Department, and Emergency Medical Transport responded to the accident.

Enbridge Inc. (Enbridge) subsidiary Enbridge Gas Ohio provided natural gas to the businesses and residences in the Realty Tower Building through a steel main and service line.[3] After the accident on May 28, Enbridge crews conducted an initial pressure test of the main and service line. The pipeline failed to hold pressure, and crews heard a hissing noise, which was coming from the cut in the 1-inch diameter inactive gas service line in the underground basement area.[4] This was the pipe the scrap-removal crewmember had cut into just before the accident.

The NTSB learned that at the time of the accident, the inactive service line had been pressurized with natural gas to about 38 pounds per square inch, gauge (psig).[5] On May 29, the inactive service line was capped, and Enbridge performed a successful second pressure test of the main and the active and inactive service lines. The pipeline held pressure, and a leak survey of the area found no other leaks.

While on scene, the NTSB visually examined the accident site, reviewed surveillance video footage, recovered physical evidence for laboratory examination, gathered information related to the basement scrap-removal contract, reviewed Enbridge operational procedures, and conducted interviews. The NTSB’s investigation is ongoing. Future investigative activity will focus on the pipeline operator’s procedures and practices for meter removal, record keeping, and abandoning gas facilities; ownership of the inactive service line; the companies associated with the Realty Tower Building; and GreenHeart operational practices and policies for work crews.

Parties to the investigation include:

• the Pipeline and Hazardous Materials Safety Administration; 
• the Public Utilities Commission of Ohio; 
• the Youngstown Police Department; 
• Enbridge; and 
• Tactical Protection & Surveillance, LLC.
  

​See the photos on Flickr​.