This 16th issue of the Lessons Learned Bulletin (LLB) focuses on industrial accidents which took place in warehouses as a follow-up on the Beirut explosion in 2020. For this study, the JRC analysed 38 reports of chemical incidents that occurred in independent warehouses. The study focused on accidents involving warehouses, distribution, and transportation centres accommodating non-stationary storage where warehousing was the main activity. Accident investigations on warehouses are frequently incomplete since the level of destruction prevents investigators from conducting an extensive causal analysis. Therefore, the study includes only accidents that have sufficient information to identify lessons associated with prevention and mitigation management.

Please note: The accident descriptions and lessons learned are reconstructed from accident reports submitted to the EU’s Major Accident Reporting System at

https://emars.jrc.ec.europa.eu 

as well as other open sources. EMARS consists of over 1100 reports of chemical accidents contributed by EU Member States and OECD Countries.

The bulletin highlights those lessons learned that the authors consider of most interest for this topic, with the limitation that full details of the accident are often not available, and the lessons learned are based on what can be deduced from the description provided.

Warehouse and distribution centre accidents can cost money and lives 

Warehouses and distribution centres have always been one of the key elements in supply chain management to accommodate the commerce demands of manufacturing facilities as well as end users. Many advancements in warehouse management have been reported in the past decades, involving automation, artificial intelligence applications, utilization of drones, etc. However, recent accidents such as the explosion in the ports of Tianjin and Beirut, in 2015 and 2020 respectively, demonstrate the need to strengthen current safety practices, since the immense effects of warehouse and distribution centres accidents have resulted in numerous fatalities, excessive environmental pollution and tremendous financial losses.

The Major Accident Hazards Bureau (MAHB) of the European Commission’s Joint Research Centre studied reports of more than 100 chemical incidents occurring in warehouses, distribution and transportation centres, available in eMARS and other open sources. The aim of the study was to understand typical causes of loss of containment, how it can lead to a major accident, and to identify practices to prevent such incidents and mitigate their effects. The findings were analyzed to provide lessons learned to support risk assessment and risk management decisions for chemical warehouse operators and inspectors. For this study, 38 cases were included in the analysis, where warehousing was the main activity (including distribution and transportation centres). Production warehouses, used for the storage of raw materials, semi-finished products and finished products were not included, since they follow a different business model and operations and activities upstream and downstream of storage may also differ substantially.

Types of facilities

Eight accidents (or 21%) took place in handling and transportation centres, such as ports and marshalling yards, including a variety of substances such as oxidisers, nitrates and end-consumer products (i.e., garments). 

Impacts and the risk of escalation and domino effects

The accidents in the study collectively resulted in 495 fatalities and at least 8,500 injuries, including members of the public and emergency responders. Four cases alone were responsible for the death of nearly 150 emergency responders. The earliest accident covered in the study dated back to 1977 while the most recent accident occurred in 2022.

By their nature, warehouses can be more prone than other types of hazardous facilities to escalation of an initial event due to large quantities of hazardous substances present in the same location and internal domino effects. There were a number of accidents in the study that appeared to demonstrate this tendency. The study included five disasters that took place in the past decade representing the majority of the fatalities and injuries counted in the study (see Figure 3), including the explosions and subsequent fires in port warehouses in Lebanon, China and Bangladesh as well as warehouses specialised in the storage of fertilisers in the United States and South Africa.

Accidents occurring in warehouse facilities can have greater potential for severe consequences offsite, and emergency responder and business impacts (see Figure 3). Throughout the study, it was quite common for warehouses to be claimed as almost or completely destroyed leading to excessive property damages, material losses and significant restoration costs. It is not uncommon for the entire stock of the warehouse to be lost as the result of such an event. Damages resulting from Tianjin and Beirut, have been estimated to be more than 5 billion euros, including also government sanctions. In these two cases, only some costs were borne by the operator, with a vastly greater portion imposed on surrounding communities and businesses in addition to the government.

Figure 3. The 10 most devastating chemical accidents in warehouses (1977-2021)

Offsite impacts can also be significant causing considerable damage to residential buildings, local shops and businesses . as well as offsite injuries in surrounding areas. In more than 40% of the events (17) the community suffered substantial disruption because of evacuation or shelter-in-place imposed on a large portion of the population, or due to having services, such as water, electricity, or road access out of order for several hours or even days. As a case in point, a warehouse fire in France led to the confinement of over 38,000 people for 8 hours in 1987. More recently, in 2013, an accident in a fertiliser warehouse in West, Texas, USA, wreaked substantial damage on the city’s infrastructure, including a public school and a nursing home.

Significant environmental pollution can also result from chemical accidents in warehouses, or either the release of hazardous substances or the firefighting operations due to uncontained firefighting water mixed with hazardous substances reaching the soil or the water basins, as was noted in 9 events in the study. The size of some warehouse fires means that emergency operations can prolong the exposure of emergency personnel to incident effects from several hours to days. Environmental impacts also tend to increase when the firefighting effort is long and drawn out. Firefighting mediums mixed with the hazardous substances, if not controlled, can enter and contaminate waterways requiring cost-intensive clean-up and restoration.

Initiating events in warehouse accidents

Chemical accidents in warehouses, like chemical accidents in other activities, are often caused by procedural errors. In the JRC study, such a mistake was the most common starting point of a chemical accident event, recorded in roughly a quarter of the reports in the study (see Figure 4). Errors were in large part associated with the mishandling of forklifts while manoeuvring (7 cases). In addition, accidental releases also occurred when a container was dropped from a certain height (2 events), also when manually transporting a product, and once because of improper positioning and stacking. Other initiating events include:

Underlying causes and escalating effects

In more than 50% of the cases studied, emergency arrangements and response planning were found inadequate (see Figure 5). Notably, in almost half of those cases, emergency responders were among the fatalities and injuries resulting from the event. Several issues related to emergency management were identified such as:

• Insufficient communication and coordination between operators and emergency responders
• Delayed notification of emergency responders
• Poor design of firewater containment systems leading to environmental pollution
• Poor design of venting of storage areas, to reduce smoke volumes in case of fire and to facilitate safe evacuation and emergency responders operations
• Lack of sufficient firefighting capacity
• Lack of fire detection systems

Insufficient training was attributed as an underlying cause in several cases (32%). These were mainly incidents associated with the mishandling of forklift operations where employees were lacking appropriate training. The lack of adequate security against external risks was identified in five events including arson and one case of accidental fire by people who had unobstructed access to the facility. For four events, the accident sequence was initiated while employees were performing maintenance operations and more specifically hot work, introducing ignition sources in the vicinity of hazardous combustible products

Other factors that were shown to contribute to propagation, escalation and intensity of a chemical accident in a warehouse include the structure and design of the warehouse, poor operating procedures, and inadequate inventory management. In little over half of the events, warehouses were not appropriately designed to accommodate hazardous substances. More specifically, as shown in Figure 6, design shortcomings acted as aggravating effects in the accident sequence due to: 

Almost 40% of reports Indicated poor management practices for hazardous substances in storage, suggesting that hazard identification and risk assessment may also not have been sufficient.
Shortcomings identified include:

Case 2 – Fire at warehouse occupied by various operators

Sequence of events
A fire broke out in a 9,600 m2 warehouse storing various chemical substances, such as arsenic trioxide, phytosanitary products, and cotton wool cellulose. The warehouse, registered as an upper-tier Seveso establishment, was divided into eight cells rented by four operators (see Figure 7). The employees noticed the fire in a cell where one of the renters stored bales of cotton wool cellulose used to manufacture napkins, tablecloths, and paper for sanitary use. They initially attempted to address the blaze using the internal hose station network. However, 20 minutes later, and following the partial collapse of a cell-separating wall, a neighbouring cell that housed agro-pharmaceutical products also caught fire. Emergency services managed to put out the fire two hours later. During the firefighting operations, 30 firemen were affected by the overwhelming smoke while 7 more required hospitalisation.

According to the investigation, more than 100kg of arsenic trioxide were released. The fire caused extensive property damage, exceeding €2,000,000, while only a part of the warehouse was salvaged. The underground water basin, including the soil and the rainwater network, was contaminated by the extinguishing water, mixed with pesticides, detergents, and soaps. Restoration and water treatment operations extended over an 11-month period.

A cloud of chlorine drifted towards a nearby waste-disposal company where 32 employees were working on the construction of a new chemical oven and notified the chemical plant of their distress. The site was evacuated, if somewhat chaotically, and the affected employees were sent to the hospital for medical check-ups.

Figure 7. Multiple operators’ warehouse layout (Image source: French Ministry of Environment)

Important findings
Most probably the fire was initiated during hot work operations being carried out on the roof of the warehouse. Employees were conducting maintenance using a blowtorch to repair damages done to the roof during winter major storms.

• The design of the warehouse, including the roof and cell partitioning, as well as the quantities stored, were considered aggravating factors in the fire propagation. Various chemicals and other products owned by the four operators were stored without adequate partitioning while good construction practices had not been followed.
• The firefighting water was collected in a non-hermitic basin. Thus, the soil, as well as the rainwater/sewage network, were polluted leading to a long, vigorous and cost-intensive process of restoration

Lessons Learned
Safe execution of maintenance operations in warehouses. As with all hazardous sites, warehouses must follow appropriate protocols to prevent dangerous events stemming from maintenance operations. In particular, cutting blowtorches, welding and other hot work are common initiators of chemical accidents on many hazardous sites, including warehouses, and most notably as a probable initiator of the 2020 Beirut disaster. It is important that only qualified personnel who have received proper instruction and training and fully understand the hazards should carry out maintenance operations. A permit-to-work system should be used to control the maintenance operations, stating the requirements of the maintenance work prior to commencing and identifying all associated risks along with necessary preventive and mitigation measures.

Building construction. Design and construction of the buildings housing hazardous substances should allow a high level of structural integrity, mitigate any possible fire scenario by incorporating fire retardant insulation and prevent debris from projecting into the surroundings in case of explosion or complete collapse. Quite commonly, burning debris from the warehouse fire propagates fires in the surroundings, damaging neighbouring commercial or residential buildings, and sometimes even leading to fatalities. Improper construction materials, such as wood or non-flame-retardant insulation foam, should be avoided because they can intensify and spread the fire. An inbuilt store within a warehouse, with proper fire protection and insulation, may also be used to store highly flammable liquids and gases, aerosols or peroxides.

Considerations in building construction should also include:

• Protection against weather. Flooding, lightning, earthquakes and other natural hazards should be considered in the design and construction of warehouses where applicable.          Flooding can be particularly dangerous when products in storage are water-reactive.
• Ventilation and smoke control. Dangerous concentrations of flammable vapours but also smoke and soot released during a fire require adequate ventilation of the warehouse. Measures to address ventilation can include fixed permanent openings in external walls and mechanical ventilation. Smoke control systems within warehouse buildings should be in place to facilitate emergency evacuation but also to assist the emergency responders in firefighting operations. (Equipment selection should take account of the potential presence of explosive atmospheres.)
• Protection against malicious acts. Warehouses are particularly vulnerable to arson and trespassing, that intentionally or unintentionally, have been known to cause accidents in warehouse facilities (including 4 cases in the JRC study). Good practice includes the installation of locks, fencing, alarms and security patrols. It also requires routine maintenance to ensure the integrity of construction elements, such as fixing damaged external walls and windows.

Design of firewater containment systems. Unburned toxic substances and firefighting mediums during firefighting operations can create a hazardous mixture that needs containment and treatment to avoid the pollution of water basins. A containment system is often required to contain firewater mixtures and to prevent them from escaping into the wider environment. These systems include, but are not limited to, tank dikes, curbing around process equipment, drainage collection systems, firewater lagoons, interceptor pits or tanks. The design of containment should also take into account the need to minimise the risk of adverse reactions of released substances due to exposure to water or incompatible substances in retention basins.

Depending on the procedures in place, firefighting water may require containment and treatment on-site or off-site contracting external services, sometimes for long periods until the restoration process commences.

Coordination of preparedness with emergency responders. There have been several disasters in the recent past, including West, Texas, USA (2013), Tianjin, China (2015), Beirut, Lebanon (2020) and Sitikunda, Bangladesh (2022), where emergency responders have been injured and killed responding to chemical accidents at warehouses storing dangerous substances.  In these particular cases, the responders appeared to be unaware of the dangerous contents of the warehouses. In each case, the warehouse operator evidently had little or no exchange with the local responders about the hazards at the site, potential accident scenarios, and appropriate intervention measures.  They also were not sufficiently aware of their own risk from potential escalation and from inappropriate or inadequate containment strategies, particularly in the case of ammonium nitrate fertilizers, a uniquely dangerous substance that was involved in 3 of these disasters.

These tragedies clearly indicate that operators have a primary responsibility to have ongoing and robust collaboration with local emergency responders about potential accident scenarios and the emergency measures in place for mitigation and response. Good practice includes among other things, sharing the hazardous substance inventory (and significant updates) and providing information on likely and worst-case scenarios. Information on firefighting measures is available in section 5 of SDS documents for example, which can be made available to the emergency services. On this basis, emergency services can receive proper training on the appropriate HAZMAT response for any hazards likely to be present in the warehouse. Moreover, establishing crisis communication protocols, and arranging emergency response exercises involving the local response community and employees, will enhance emergency preparedness.

Emergency procedures for all potential scenarios. As with all hazardous activities, there should be an internal emergency plan in place that is implemented at the earliest stage of an incident. Among other things, these procedures should take into account the hazardous properties and quantities of the potential substances that may be stored in the warehouse at any time.  Emergency response should be designed with the warehouse structure and storage plan in mind, defining effective containment strategies as well as alternative escape routes for different scenarios.

Source: ARIA N° 18379

Case 3 – Fire at a refilling and distribution centre for liquefied and compressed gas cylinders

Sequence of events
During a period of extreme heatwaves, consisting of bright sunlight and ambient temperatures exceeding 36°C, several explosions followed by fire took place at a bottling plant. The facility fills and distributes liquefied and compressed gas cylinders, rents welding machinery, and sells welding supplies. During normal operations, it has about 30,000 compressed gas cylinders containing oxygen, nitrogen, propane, propylene, acetylene, carbon dioxide, helium, and other speciality gases onsite, employing around 70 people. A technician retrieving cylinders from an outside storage area saw a three-meter-high flame coming from a cylinder and activated the fire alarm. As workers and customers evacuated, the fire spread to adjacent cylinders. After 4 minutes, the fire covered most of the facility’s flammable gas cylinder area and chain explosions took place.

With explosions propelling cylinders in all directions inside and outside the facility, firefighters set up a perimeter, evacuated local residents, directed a water stream on the fire, and extinguished secondary fires started by burning cylinders and projectiles landing offsite. The fire was finally controlled following a 5-hour intervention. Damages included a burned-out empty commercial building, burned cars, a one-meter hole in the wall of one residential building, broken windows, and other destruction to residential and commercial buildings. Cylinder parts travelled as far as 250 meters from the area of the explosions. The fire plume spread asbestos from ruptured acetylene cylinders approximately over a 1,5km wide area, while one resident experienced a severe asthma attack and died. The facility was extensively damaged by the fire and the extinguishing water while about 8,000 cylinders were also destroyed.

Important findings
Direct sunlight, as well as radiant heat from the asphalt, heated the propylene cylinders, while high ambient temperatures limited any natural air-cooling. Moreover, the returned cylinders, where the fire started, contained less gas than full cylinders, started heating up at an elevated rate. As the cylinder wall temperature rose, the internal pressure increased, causing the relief valve to open and vent propylene. Probably due to an electric spark or discharge, the released propylene was ignited.

• Temperature of the nearby cylinders rose, as the heat from the fire was supplementary to the heatwave, releasing more propylene into the fire. As a result, the liquefied petroleum gas (LPG) area of the facility became fully involved in the fire.
• Barriers to limit the spread of fire and explosion, deluge systems or fixed fire nozzles to cool cylinders in case of a fire as well as gas and fire detection systems that can activate alarms and fire mitigation systems were lacking.

Lessons Learned
Implementation of required storage protocols for hazardous materials. A critical principle of safe storage of hazardous goods is the strict adherence to safety protocols associated with the substance in question. In this particular case, the substance consisted of propylene and propane cylinders. Standard practices for storing cylinders are well-known and include maintaining recommended safety distance between cylinders, organising full and empty cylinders in separate locations, separating storage compartments for cylinders from any potential heat sources, and distancing them from flammable and combustible liquids that could easily ignite.

Packaging and storage standards for different types of hazardous substances typically address a number of elements, including the type of container and its composition, the degree of isolation or distance to be respected from other types of materials, temperature conditions, bonding and grounding of static electricity, and other parameters. For example, flammable substances should generally be stored only in dry, well-ventilated areas that are not exposed to heat or direct rays of the sun, or lightning. Special attention may be required for specific substances, such as ammonium nitrate, whose unique properties require particular handling and storage conditions. Measures should also include any controls necessary to combat climate and weather extremes of the location, for instance, potential excess humidity in port locations.

Handling and storage guidelines for dangerous substances with all hazardous properties, e.g., flammability limits, water reactivity, etc and optimal storage conditions (i.e., temperature and humidity) are available through the SDS which should be consulted before substances are sent to storage. If the correct storage conditions cannot be met for particular dangerous substances, then they should not be permitted in the warehouse.

Detection mechanisms and mitigation systems. Warehouses should adhere to recommended practices for detecting liquid and gas releases, changes in temperature, or other warning signs specific to the range of substances stored in the warehouse. Detection systems are often coupled with automated safety systems that are programmed to trigger alarms and mitigation measures (e.g., deluge systems) when parameters are exceeded. For example, for gas cylinders, detection of flammable gases should be in place to dissipate the gas before ignition, reducing the likelihood of uncontrolled fires. Fixed fire protection such as fire monitors, deluge, or sprinkler systems can immediately cool cylinders reducing the likelihood of additional cylinder releases, fire spread, and off-site consequences.

Firefighting medium (water, foam or other agents) should be used according to the hazard classification of the substances in storage avoiding any reaction between the firefighting medium and hazardous substances. The SDS contains all relevant information on suitable firefighting mediums as well as advice for firefighters.

Internal site planning. The placement of hazardous substances and the location of storage units should also consider domino effects of potential accident scenarios involving the dangerous materials in storage. For example, burning cylinders and fragments, acting as projectiles, can strike people and property both onsite and offsite, sometimes causing significant harm. They can even cause an escalation in the accident sequence if they hit another hazardous substance container, which then may also explode or release noxious gas or fluid. In this context, warehouse operators may consider storing hazardous substances under reinforced structures to mitigate the effects of an explosion as well as assess the facility’s segregation policy.

Land use planning. Potential offsite consequences on urban areas should be thoroughly assessed, considering appropriate safety distances from residential buildings and the warehouse structural design elements that can minimise the possibility of impacts offsite. The high potential for domino effects, when mitigation measures are inadequate to control the event escalation, can represent a very high risk for offsite populations and structures. In this particular case, the projectiles from the explosion of gas cylinders reached an area of 250m from the epicentre of the main explosion. The Tianjin, China warehouse fire (2015) and the fire and explosion of a fertiliser warehouse in West, TX, USA (2013) are both examples of the excessive danger that serious warehouse fires and explosions pose to their surroundings due to expulsion of projectiles, massive overpressure, and the propagation of fire to nearby objects and structures.

Source: United States Chemical Safety and Hazard Investigation Board, Praxair Fire

Motto of the year:

“Try to change situations, not people…”

Kletz (“An engineer's view of human error” ,1985)

You can access the eMARS database here:

https://emars.jrc.ec.europa.eu 

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