Blast at Welsh Steelworks

On November 8, 2001, a major explosion occurred at a steel manufacturing plant in Port Talbot, South Wales, fatally injuring three employees, while a dozen more were hospitalized. The incident occurred when water and hot molten steel reacted, causing a rapid accumulation of internal pressure and the explosion of No. 5 Blast Furnace.

In seconds, over 5,000 tons of steel had lifted into the air, spewing several tons of molten iron onto the factory floor. Combustible dust and gases blew hundreds of feet above the furnace and then ignited. According to The Guardian, “workers ran for their lives as a river of liquid metal at 1,100°C splashed over their cast house floor at high speed, igniting everything in its path.”

As the furnace collapsed, pipes ruptured, flooding the area with boiling hot water and steam. Flames shot up into the air over 100 feet and thick smoke choked the air. It took 18 hours and more than 80 firefighters to bring the fires under control.

The Health and Safety Executive (HSE) report identified failings in the risk management of critical areas in operations, as well as a disregard for safety procedures. The lessons learned had a far-reaching effect on the steel and manufacturing industries.

How the Incident Began

Steelmaking has existed at Port Talbot for many decades. The factory was owned at the time by Corus UK Ltd. And had 3,500 employees and many contractors onsite at the time of the incident. Iron was made on-site from raw materials in two different blast furnaces. No. 4 Blast Furnace was constructed in the 1990s and had a more modern design.

No. 5 Blast Furnace was built in the 1950s and in this one, the raw materials (iron oxides) were charged into the furnace at the top and then made their way down where they chemically reacted to make molten iron and slag. As it made its way down the furnace the material was blasted with air that was preheated to 1100° C (2012° F). The molten iron and slag were then drained off at the bottom of the furnace at regular intervals. Additionally, due to the large amount of heat generated, the furnace shell needed to be cooled through several cooling elements such as circulating cooling water. Gas produced from the process was conveyed from the furnace to a gas plant through a large, inclined pipe. Bleeder valves needed to remain at the top to control gas pressure.

Before the incident, there had been issues with the cooling system because monitoring systems had detected water leaks. It was discovered that two of the three primary cooler pumps had failed and were taken offline. This caused a considerable amount of overpressure to accumulate in the furnace due to the interaction of water and hot molten material at the bottom.

Incident Investigation

Just before the incident, employees reported hearing a rumbling sound. Suddenly the whole furnace structure parted at its lap joint, allowing extremely hot gases and molten material to exit the structure. It was estimated that 200 tons of liquid, solid, and semi-solid material exited the furnace onto the floor below. As pressure decreased, the structure fell back down offset from where it normally lay. This movement severed many of the cooling water pipes. A joint investigation by the South Wales Police and the HSE found that 50-80 tons of water had entered the furnace the day before during issues that had been encountered with the water-cooling system. In attempting to restart the furnace, water came into contact with the molten materials, which caused a significant energy release. The cooling system was unable to deal with the heat produced since it was crippled from the previous day. This led to an explosion due to overpressure.

Lessons Learned

Process Hazard Analysis (PHA)

In the case of the steelworks explosion at Port Talbot, an improper risk assessment was made on the number of cooling elements required for safe operations. Unfortunately, Corus UK Ltd. did not include their blast furnaces as part of their Process Hazard Analysis (PHA) assessments, yet as we saw in this explosion they are a key part of the chemical process. Under the Control of Major Accident Hazards Regulations 1999 (COMAH), it is essential to identify and evaluate risks and hazards associated with a chemical process. Principal methods for pinpointing weaknesses that could lead to chemical releases, fires, or explosions are Hazard and Operability Studies (HAZOPS), Failure Modes and Effects Analysis (FMEA), Fault Tree Analysis (FTA), Process Hazard Review (PHR), and Layers of Protection Analysis (LoPA).

Process Safety Office^® PHAGlobal^® provides process safety and risk professionals with an integrated suite of tools for process hazards analysis, auditing, consequence analysis, risk analysis, and more. It contains pre-populated templates for conducting risk analyses using different techniques such as Hazard and Operability (HAZOP), What-if?, and Checklist (including Facility Siting and Human Factors). In addition, PHAGlobal^® also contains pre-populated checklists to address combustible hazards as part of a Dust Hazard Analysis (DHA) and pre-populated templates to perform Layer of Protection Analysis (LOPA) and Failure Mode and Effects Analysis (FMEA).

An effective follow-up system for action items is also a critical element to ensure that each recommendation is addressed in a timely manner. OSHA recommends facility managers regularly validate and document that closure of action items has occurred and that closure is documented. OSHA also recommends they review that equipment process safety information (PSI) complies with recognized and generally accepted good engineering practices (RAGAGEPs). Also, ensure that the information is being properly filed and managed, and is readily available.

The Process Safety Enterprise^® platform makes it easier to conduct a quality PHA, track follow-up actions, enable knowledge sharing across one facility or many, and simplify compliance for organizations. Enables tracking and sharing of action items, assigning and scheduling tasks, collaborating with teams and contractors, and storing all information ― including employee training records ― from one shared database.

Chemical Reactivity Testing

Reactive incidents are not unique to the chemical manufacturing industry. They also occur in many other industries where chemicals are stored, handled, or used. The risks of water/metal and water/slag coming into contact in a confined space were substantial at Corus UK Ltd., yet not fully understood or appreciated. HSE stated in their incident report, “Specifically, with water systems on blast furnaces, a ‘leakage tolerant’ attitude should not be allowed –especially with older furnaces.”

If they had done lab testing, meaningful reactivity information from the data would have been extracted and incorporated into their facility's process safety program. Large hazardous facilities must create a safety case in which specialists identify the reactive hazards of their process according to UK regulations. OSHA’s PSM Standard also requires that chemical reactivity hazards be identified as part of the process safety information (PSI) element.

The experts at ioKinetic conduct chemical reactivity testing using many instruments, including thermogravimetric analyzers (TGs), differential scanning calorimeters (DSC) and the Accelerating Rate Calorimeter (ARC^®), and low phi-instruments, such as the Vent Sizing Package (VSP) and the Automatic Pressure Tracking Adiabatic Calorimeter (APTAC™). Chemical reactivity testing will assist you in reducing hazards that you may otherwise not be aware of, and help you comply with regulatory standards.

Process Safety Training

Failure of cooling elements can lead to thermal runaways like the one that occurred at Corus UK Ltd. The investigation into the incident noted that operator training was inadequate for locating the leaks in the No. 5 Blast Furnace which allowed a large amount of water to accumulate at the bottom of the furnace. Workers should also have been better trained in the hazards associated with water and molten materials coming into contact as they pose a significant operational hazard.

The HSE report recommended, “Employees should have a precise and clear view of their roles and responsibilities in emergency or abnormal process conditions, and be supported by suitable training, procedures, and other job aids.”

At this facility, the lack of training not only compromised safety, but caused significant property damage, and led to court fines in the millions. COMAH regulations require workforce and contractor training for the successful prevention of major accidents in the workplace. When a team member's competency deficiency is identified during a PHA, a compliance audit, or a process Management of Change (MOC), this can only be mitigated through education, training, and experience. We can help. Our training experts can develop and customize process safety training materials to suit your organization's specific needs and requirements. Choose from in-person, virtual, online, or a combination of approaches.

We Can Help

ioKinetic has reduced process safety risk, maintained compliance and substantially increased peace of mind for our clients worldwide. To learn more about how we can help you manage risk, contact us today or call us at 1-844-ioKinetic.