CSB Releases Final Report Into Fatal 2019 Explosion and Fire

CSB Releases Final Report into Fatal 2019 Explosion and Fire at KMCO Chemical Facility in Crosby, Texas
Washington, D.C. December 21, 2023 – Today the U.S. Chemical Safety and Hazard Investigation Board (CSB) released its final report into the fatal explosion and fire at the KMCO production facility in Crosby, Texas. On April 2, 2019, KMCO was producing sulfurized isobutylene as a lubrication additive. The explosion and fire occurred after isobutylene leaked from a fracture in a segment of piping and formed a flammable vapor cloud, which ignited.
One KMCO employee was fatally injured, and two others were seriously injured.  At least 28 other workers were also injured. Portions of the KMCO facility were substantially damaged from the explosion and subsequent fires. News outlets reported that the explosion shook nearby homes and was heard throughout the surrounding community.  Local authorities also issued a shelter-in-place order for residents within a 1-mile radius of the facility that lasted for more than four hours. 
CSB Chairperson Steve Owens said, “The tragic death and injuries caused by this terrible event should never have happened.  KMCO did not properly train its employees and did not give them adequate protective safety equipment.  KMCO also failed to heed industry guidance about the need to install remote isolation equipment so that its employees could have safely stopped this serious hazardous leak.”  
The CSB’s final report determined that the isobutylene release occurred when a piece of equipment called a y-strainer ruptured due to brittle overload fracture. Specifically, the cast iron y-strainer was installed within an area of the piping system that, unlike other portions of KMCO’s isobutylene piping, was not equipped with a pressure-relief device or otherwise protected from potential high-pressure conditions. Therefore, when those conditions developed, most likely due to liquid thermal expansion, the y-strainer was subject to high internal pressure and ruptured releasing isobutylene which formed a vapor cloud. This flammable cloud most likely ignited from contact with electrical equipment within a poorly sealed, nearby building.
The CSB’s report identified three key safety issues that contributed to the severity of the incident. They are:  
  1. Emergency Response. KMCO’s procedures and training did not properly limit the role of its operators during the emergency response. KMCO’s plant culture relied on unit operators taking quick actions to stop a release before the site’s emergency response team assembled. While those urgent communications and quick actions did help move many operators away from the danger, the workers performing the quick actions were at risk. KMCO could have reduced the severity of the April 2, 2019, event by establishing clear policies and training its work force to not put themselves in danger at all to urgently stop a chemical release. 
  2. Remote Isolation. When the y-strainer ruptured, KMCO’s workers lacked the safety equipment they needed to stop the isobutylene release from a safe location, such as from within the blast-resistant control room. Hazard Evaluation.
  3. Hazard evaluation is one of the most important elements of a process safety management program. KMCO’s hazard evaluations consistently overlooked or misunderstood that its y-strainer was made from cast iron, a brittle material that existing industry standards and good practice guidance documents either prohibit or warn against using in hazardous applications, such as KMCO’s isobutylene system. 
Investigator-in-Charge Dan Tillema said, “In addition to highlighting the safety issues present at KMCO, our report emphasizes seven key safety lessons that can help prevent a similar incident. One such lesson is that the goal of keeping workers safe and the goal of quickly isolating releases to minimize the consequences of an incident should not be mutually exclusive. Both can be achieved by applying robust safety systems and establishing effective emergency response programs.” 
Following the April 2, 2019, incident, KMCO filed for bankruptcy, and the company is no longer in business.  Altivia Oxide Chemicals, LLC (Altivia) purchased the Crosby, Texas, facility in 2020 and informed the CSB that the process involved in the incident would be dismantled.  As a result, the CSB is not issuing recommendations with this report.
Nevertheless, the CSB is urging Altivia to read the report closely and understand the factors that led to the incident at the KMCO facility and the lessons stemming from it.  Moreover, if hereafter Altivia reinitiates the process or any equipment involved in this incident, the company should ensure that the facts, conditions, and circumstances that caused the incident — and contributed to its severity — are not repeated.
The CSB’s board members are appointed by the President subject to Senate confirmation. The Board does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA.
Please visit our website, www.csb.gov. For more information, contact Communications Manager Hillary Cohen at [email protected]
Back to news