A federal chemical safety agency concluded that Shell had inadequate safety and training measures that led to an explosion at the company’s Beaver County ethane cracker on June 4, 2025.
No one was injured in the blast, but 15 employees were evacuated, and the accident resulted in $95 million in damages.
In its final report on the explosion, the U.S. Chemical Safety and Hazard Investigation Board revealed that the explosion occurred when employees at the plant inadvertently opened two valves, allowing explosive gas ethylene to accumulate near a flame.
The agency found one of the engineers who initiated the procedure that precipitated the explosion “had never previously performed the task” and that employees at the plant “had not been adequately trained prior to this incident and lacked awareness of” the company’s safety protocols for the operation.
As a result, the report said, over 600 pounds of gas accumulated in a part of one of the plant’s furnaces, “resulting in an explosion that blew out of the furnace’s walls.”
In total, over 5,000 pounds of ethylene, a chemical the plant produces at the Monaca facility, were released.
The agency also cited as a factor in the explosion the company’s lack of mechanical safeguards. Shell did not set up a control panel provided by the equipment manufacturer that could have been used to block the flow of gas during the procedure.
The safety board said another factor was the use of a confusing command screen system in the explosion. That system “lacked clear labeling…and safeguards such as confirmation steps” for opening and closing valves. Three valves, for instance, were labeled with numbers that “differed only by the last digit” on a screen that “was not sufficiently intuitive or clear to facilitate valve identification,” the report said.
In December, the Occupational Safety and Health Administration fined the company $26,000 for the explosion.
In a statement, the company said that it has “taken steps to strengthen our operations” since the explosion “through a comprehensive review, corrective actions, and application of lessons learned. Safety remains our highest priority for our employees, our neighbors and the environment.”
The plant started production in November 2022. It was built with help from a $1.65 billion tax credit, the largest in state history. It makes plastic pellets out of the region’s natural gas.
The CSB recommended that Shell “[i]mplement an inherently safer design or an engineered control for any scenario…that could result in a fatality, serious injury, or substantial property damage.”
Hilary Starcher-O’Toole, an area resident and executive director of the local watchdog group Beaver County Marcellus Awareness Community, said many of the details in the report had never before been made public.
“The fact that all of these things are dependent on human controls and human error, and some of these individuals may not be trained properly, that’s really terrifying,” Starcher-O’Toole said. “It’s terrifying as a resident knowing what can happen with unexpected and unanticipated explosions, just based on having all of the hazardous chemicals that they have and the processes that they use.”
The plant has had problems since starting up; in 2023, the state fined the company $10 million for air pollution violations. Earlier this month, the state issued another $15 million fine for air violations.
Starcher-O’Toole expressed frustration that Shell has not disclosed to the community what it is doing to prevent similar accidents at the plant in the future.
“We’re constantly left in the dark,” Starcher-O’Toole said. “This is something to me that should never have happened because they are a global petrochemical [company]. They have multiple different plants …across the globe, how can mistakes like this be happening here?”
Matthew Mehalik, executive director of the nonprofit Breathe Project, said he feared that problems like the explosion are a preview of what is to come for Beaver County.
“These plants are complex; they have accumulating problems that can occur. They leak. They have, they process dangerous chemicals, they release dangerous chemicals,” Mehalik said. “Unfortunately, the community has to deal with these sorts of things.”
