The blast at the factory in Saint Louis, Missouri, US, on April 3 killed engineer Kenneth Trentham, 59, at Loy-Lange Box Co. and Clifford Lee, 53, Tonya Gonzalez-Suarez, 43, and Christopher Watkins, 46, when the storage tank hurled through the roof of Faultless Linen. One other person remains hospitalized.
Corrugated box manufacturing
CSB said in a statement, the vessel which launched into the Faultless Linen building was a vertical condensate storage tank, technically referred to as a SCR (semi-closed receiver).
The SCR provided the condensate or hot water to a steam generation and supply system supporting a corrugated box manufacturing process. That process was being started up on the morning of the incident. Initial visual examination suggests the bottom pressure boundary of the SCR failed.
According to Vanessa Sutherland, chairwoman, CSB investigators will conduct a more thorough inspection of the SCR once it has been removed from the building.
“According to initial calculations performed by CSB investigators, the SCR contained about 510 gallons of water and was operated at about 330°F and 100 psig,” she said.
“The SCR itself is roughly 20 to 25 feet tall and about 3 feet in diameter and about 3000lbs. When the vessel failed, the hot condensate jetted from the bottom, converting from hot water to steam. The power of the jet of water rapidly turning to steam broke the vessel loose from its piping attachments and fastenings, propelling it through the internal structure and roof of the building.
“The downward force of the steam launched the 3,000lb vessel with a speed of about 120mph, about 425 feet into the air and about 515 feet from its starting point. The SCR remained airborne for over 10 seconds.”
The CSB is an independent federal agency which promotes chemical safety through independent investigations. It looks at all aspects of chemical incidents, including equipment failure, inadequacies in regulations, industry standards, and safety management systems.
F&B POP displays
Loy Lange Box Company founded in 1897, makes corrugated boxes, POP (Point of Purchase) and pallet displays for the food and beverage industry among others.
According to the Occupational Safety and Health Administration (OSHA) the company has been fined for violating workplace regulations three times in the past three years.
In August 2016 it paid $3,741 after inspectors found holes in floors that prevented proper cleaning.
In November 2014, an inspection found damaged and defective equipment fining the company $6,566. And in February 2014, the company paid $2,450 for violating procedure protocols, including inadequate training for employees to check if machinery was powered down.
CSB said the structural integrity of both buildings is now being assessed. One crew was able to enter an area deemed safe at the Loy-Lange facility to 3-D photo-document the scene and this information will be used to further assess the site and determine next steps to stabilize the building.
Protocols to remove the SCR from the Faultless building are underway.