CSB Shares Update from Investigation into Fatal Explosions at Explosives Manufacturer
An update from the Chemical Safety and Hazard Investigation Board describes the work tasks being performed at Accurate Energetic Systems, an explosives manufacturing facility in Tennessee, on the morning of Oct. 10, 2025, when a series of explosions killed 16 people and injured several others. CSB learned from surveillance footage that in the 17 minutes leading up to the first explosion, employees were performing tasks related to the manufacture of cast boosters, or solidified explosives housed in cardboard or plastic tubes that are used in industries like mining and demolition. The footage showed workers pouring highly explosive mixtures into these cast boosters as well as managing kettles, preparing booster tubes for pouring, removing solidified boosters, packaging finished products for shipping, and handling materials.
According to CSB’s update, the first explosion likely occurred on the ground floor of the building, creating a pressure wave that likely set off additional explosions. Of the approximately 24,600 pounds of explosive material present in the building, the agency estimates that 23,000 pounds detonated, deflagrated, or burned during the incident. The Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), which responded ahead of CSB, recovered around 1,000 pounds of unexploded energetic material that was launched from the building by the explosions. ATF disposed of this additional explosive material by burning it on site.
The materials involved in the explosions were “high explosives” such as trinitrotoluene, or TNT; cyclotrimethylene trinitramine (RDX) and pentaerythritol tetranitrate (PETN), which are both solid, white, crystalline high explosives; RDX Composition B, a mixture of 60 percent RDX and 40 percent TNT; tritonal, which CSB notes has similar properties to TNT but with increased explosive power; and pentolite, a mixture of PETN and TNT that is used to make explosive charges.
“The high explosives involved in this incident were ‘secondary explosives,’ meaning they were designed to require the use of a ‘primary explosive’ to initiate an explosive reaction,” CSB explains. “Secondary explosives, however, may still be ignited by other sources of energy, such as heat, friction, or impact.”
The agency’s investigation is ongoing. Areas that CSB plans to cover during its investigation include the cause of the incident, the company’s explosive safety and process safety management programs, the equipment design of the kettles used at the facility, the sensitivities of in-process explosive materials, and industry guidance for commercial facilities that manufacture explosives.
Further details can be found in CSB’s update (PDF) and an agency news release.