Explosion investigation

Published:  25 April, 2018

The 2017 explosion in Packaging Corporation of America’s paper mill could have been prevented, says CSB final report. SEE ANIMATION

A combination of process hazard analysis, effective safeguards, safer design and a clearly defined responsible person could have prevented the non-condensable gas system explosion that killed three and injured seven workers.

The explosion occurred on 8 February last year at the pulp and paper mill in DeRidder, Louisiana, around 400km southeast of Dallas.

The contract workers had been performing hot work above a tank that contained flammable materials at the time of the explosion, which occurred during the facility’s annual shutdown.

At the time of the incident, the workers had been welding on water piping above, and disconnected from, a 38,000-litre storage tank.

The tank contained around 3m of foul condensate liquid composed mostly of water. It also contained a floating layer of flammable hydrocarbons, in the form of residual turpentine and other sulphur-containing compounds. Under normal operations the atmosphere inside the foul condensate tank is not explosive.

The US Chemical Safety and Hazard Investigation Board found that on the day of the incident there was more flammable turpentine present on top of the water than expected.

The foul condensate tank was designed so that residual turpentine would be skimmed off the top of the water and sent downstream to a turpentine recovery system at regular intervals. However, in the months leading up to the incident, confusion as to who at the mill was responsible for foul condensate tank operations led to turpentine accumulating in the tank. Although the presence of some air in the vapour space of the foul condensate tank is considered normal, because of the non-routine conditions present during the annual shutdown, more air than usual found its way into the tank, resulting in an explosive atmosphere.

Prior to the explosion, a combustible gas detector had been used to test the flammable atmosphere outside of the foul condensate tank where the repairs would occur. However, as the operators were unaware of the dangerous mixture of air and turpentine that had accumulated inside the foul condensate tank, this area was not tested.

The CSB investigation has determined that hot work activities likely ignited the contents of the foul condensate tank, which exploded and separated from its base, launching up and over a six-story structure before landing on process equipment approximately 114m away.

The CSB noted that process safety management regulations issued by the Occupational Safety and Health Administration did not apply to the mill’s non-condensable gas system, which is the process at the facility that included the foul condensate tank. It has pointed out that nevertheless good-practice guidance recommendations existed to voluntarily apply those kinds of rigorous safety management systems to the process, which were not followed by PCA.

The CSB has stated that the use of a more robust safety system approach could have helped PCA to identify, evaluate, and control the hazards present in the process, and likely could have prevented the explosion. In particular, the CSB found that the explosion could have been prevented if PCA had conducted a process hazard analysis for the non-condensable gas system; applied effective safeguards to prevent a non-condesable gas system explosion; evaluated safer design options that could have eliminated the possibility of additional air entering the foul condensate tank; and established who at the mill was responsible for operation of the foul condensate tank.

In its final report, the CSB has issued safety guidance to the pulp and paper industry. It has also issued a recommendation to PCA to apply process safety management principles to non-condensable gas systems, even if not required by regulations.

The CSB has also reiterated a 2002 recommendation issued to OSHA to cover under their Process Safety Management standard atmospheric storage tanks that are interconnected to a covered process, such as the foul condensate tank.

An animation showing the sequence of events is available to view here:

To download the final report click here.

  • Operation Florian

Sign up: eMagazine & eNewsletter

The latest issues in your inbox.

Company Profiles

Renka´s Fire Engine No. 1

Firefighting, fast, safe, everywhere. Michael Renka GmbH, based in Germany, is a manufacturer of firefighting vehicles, pumps and rescue equipment.

Waterax - We move water

Trusted by wildland firefighters around the world, WATERAX sets the industry standard by developing innovative, portable fire pumps and water-handling equipment designed to withstand demanding applications and rugged environments.

Big Water Flow for Industrial and Municipal Firefighting Applications

Protecting the lives of the public and firefighters while limiting the structural damage caused in large scale fires is our primary mission

We are committed to improving lives and doing business in the right way

We have a unique mix of capability and culture that we refer to as 3M Science and we strive to develop products that improve people’s daily lives in a multitude of ways.

HazSim - Bringing situational HazMat training to life

HazSim, LLC provides innovative simulation training to ensure your team works safely and effectively. HazSim Pro simulation equipment is in use by hundreds of fire departments, training schools, industrial fire teams, and private trainers across the US, Canada and further afield as well as the US Army.

The ultimate in innovation, quality and service

For 60 years Lehavot has been delivering the world’s most advanced fire detection and suppression automatic systems

Advancing rescue technology

The specialist supplier of quality PPE and Rescue Equipment to Emergency Services.

Revolutionizing fire fighting foam technology

The one-stop resource for fire fighting foam concentrates and custom-designed foam suppression systems hardware.

Trust the best, let us be your foam solution

AUXQUIMIA is a Spanish company whose main activity is the design, manufacture and commercialization of firefighting foam concentrates.

Williams Fire & Hazard Control offers a full line of specialized fire response equipment for oil and gas platforms

From storage tanks and pipeline emergencies to offshore platforms and vessels at sea, Williams' response personnel and specialized equipment quickly address adverse fire emergencies.

The leader in truck-mounted hydraulic platforms

Our mission is to provide the best and the safest solution to professionals that work at height.

If you want quality, you want Zico

Since its inception Ziamatic Corp has provided the men and women of the fire service with products designed to make their jobs safer and easier.

The independent alternative

Dafo Fomtec AB is a privately owned company with head office in Stockholm Sweden and manufacturing in Helsingborg in the south of Sweden.