Become Natech Savvy

Article by Aimee Russell

Aimee Russell highlights the issues you probably haven’t thought about when it comes to extreme weather risks and what you should do about them

HAVE you ever thought about the impact a natural hazard could have on your site? Have you identified which natural hazards are even credible? For upper tier Control of Major Accident Hazards (COMAH) establishments there is an expectation from regulators that duty holders are aware of external hazards, but what does that really mean? What about sites which do not fall under these regulations? Does that mean they shouldn’t be concerned with such hazards?

What would you do if the forest adjacent to your facility caught fire? Or if the only major roadway to your plant was cut off by flooding? What if the flooding triggered soil erosion or a landslide that engulfed your generators? What about the risk of your underground storage tank lifting in a flood? All these things have happened at facilities around the world and as climate change drives more extreme weather, the risks that they occur elsewhere are climbing too. Are you prepared?

What is a Natech?

Natural hazards triggering technological accidents, or Natechs, occur where a natural event, such as a flood, result in the loss of safety and/or operation at a hazardous installation.

When looking at the natural hazards impacts to your site, it is important to look at the site as a whole. For the most part, natural hazards are widespread, so can impact many things and many areas at once. Taking the example of a fuel farm, you may have dedicated studies for each mode of operation, such as import, storage, and export, which also assess the risk from natural hazards such as flooding. But have you stepped back to look at the combined risk if all three areas of the site are flooded at once? Is this event considered to its fullest extent?

The way in which I approach such hazards, and recommend that duty holders approach them, is to have a standalone document which looks at all the risks from natural hazards to your site and includes any barriers or emergency response considerations. You can, and in most cases should, still break your site into more manageable sections, as this is an easier way to work out the overarching risk picture. Inclusion of a table summarising which events could constitute a major accident hazard can also be helpful for identifying the higher risk areas of the site. Additionally, by considering all areas of the site, you will be able to see where you need to focus efforts to help mitigate this risk. Remember, natural hazards do not only pose safety and environmental impacts, but they can also have serious impacts on reputation and business and may result in plants being shut down for extended periods.

What would you do if the forest adjacent to your facility caught fire? Or if the only major roadway to your plant was cut off by flooding? What if the flooding triggered soil erosion or a landslide that engulfed your generators?

While considering your risk you also need to think from other perspectives. By this, I mean you need to think about all the consequences which could arise. For example, what happens if your control room floods, or you lose access to your control room because the area around it is severely flooded? Can you still make your plant safe? Are you expecting operators in the control room to stay put for an unknown period? Do they have access to food, water, or an area where they can get some rest? It is important to know what equipment may flood, but it is also important to step back and think about the other aspects, including employees and site access. You also need to consider if any other natural hazards may occur as a result of the initial event. For example, in the 2011 Japan earthquake, the Fukushima nuclear plant had provisions to protect against an earthquake, which were successful. It was the secondary hazard, a tsunami, which resulted in the Natech event.

Site access is a significant consideration as part of the emergency response plans for such events. You need to make sure you understand which routes may be cut off, and the implications this may have on both personnel evacuating the site and the ease with which external emergency responders can access it. Bear in mind too that the often widespread nature of natural hazards is likely to mean that emergency services are already stretched. This is especially the case with events such as windstorms and flooding. More localised events, including lightning strikes, could have less onerous consequences for external emergency responders, but they may still have a higher workload due to localised fires and fallen trees, for example.

Access and movement around your site also need to be considered. Is there anywhere of importance which may be cut off? Do you need to make sure you can move any containers of materials which could decompose?

Burned containers at the Arkema site

Arkema chemical plant incident

In 2017, flooding at the Arkema chemical plant site in Crosby, US caused by Hurricane Harvey compromised some of the refrigeration systems containing organic peroxide products. The decision was made to move the peroxides to standby refrigerated trailers to keep the products cool. As the storm progressed, and with flood levels rising, the site’s generators failed, resulting in a loss of power. Although back-up generators were used, operators believed these were going to flood too so the decision was made to transfer the remaining organic peroxides from the last functioning refrigeration system. The rising floodwater caused the failure of the vehicles used to move the trailers, and eventually of the forklift trucks loading the trailers. After the trailers were eventually loaded by hand and with no vehicles able to aid in their movement, three of the nine trailers were left on low-level land next to a warehouse. These trailers began to flood and fail, resulting in the decomposition of the material and the trailers igniting. Fearing a loss of cooling capacity in the trailers that had been moved to higher ground, emergency responders initiated a controlled burn. Over the course of the fires, in excess of 350,000 lb of organic peroxide combusted. As a result, more than 200 residents living within 1.5 miles of the facility were evacuated and prevented from returning home for a week.1

What is the risk today?

The impact from natural hazards also extends beyond the physical damage caused. There can be a significant impact on the mental health of people involved, with an increase in issues relating to substance abuse, anxiety, depression, and even post-traumatic stress disorder (PTSD) which can last months to years following an event.2 It is therefore vital that the potential impact and implication of human factors is fully understood. This includes whether instructions are clear for personnel to make the site safe in the first place. Natural hazards bring with them the risk of personal injury, but also the loss of wider communication. Therefore, is it clear who will make decisions if the envisaged person is not available?

Climate change is currently a hot topic but an aspect which is sometimes missed when discussing climate change and Natech risk assessments is, what is my risk today? Can you honestly say you understand and know your current risk from these events? Before you can even think about climate change, you need to understand your baseline risk. It’s all well and good adding climate change into various studies, but how will you know what that change will look like, or where to put in the trigger points for installing new barriers, if you don’t fully understand your risk now.

When considering barriers for helping to mitigate risk, it is important to remember that the barriers do not necessarily need to be installed tomorrow. This is part of the reason it is so important to understand your risk now and in the future. It may be that some barriers should be installed in the next ten to 20 years to ensure your risk is mitigated, but the installation of the barrier today would provide little to no benefit. For ideas of the sorts of measures which could help, looking to other industries may prove useful. Property resilience features such as flood doors may be helpful to protect switch rooms and control rooms. However, care should be taken that you are not impacting the safety and/or environmental risk of your site by installing such measures. For example, a key aspect of surface water management is the use of permeable paving to allow rainwater to naturally drain into the soil rather than running off into the drainage system. However, for high hazard sites, the recommendation to protect the environment from releases is to ensure impermeable paving to prevent contamination of soil and groundwater.

You also need to ensure you understand what events are credible. It is important to remember that some natural hazards have longer timescales and duration periods. Therefore, arguments along the lines of “Well, this hasn’t happened in 100 years”, or “Bill has worked here all his life and he’s never seen it flood”, are not valid when looking at these types of events. Always expect the unexpected with natural hazards.

Also, do not rely on existing defence mechanisms as your sole reason for the event not being able to occur; these mechanisms can, and do, fail. For instance, in 2013 the flood defences at the Inter Terminals Riverside Terminal in Teesside, UK were damaged and overtopped following a storm surge, resulting in flooding. At nearby SABIC Brinefields, 50 m of the flood embankment was washed away resulting in flooding on the site with each tide.3 This highlights the need to still assess the risk to sites, even when barriers exist.

Do not rely on existing defence mechanisms: in 2013 flood defences in Teesside, UK were damaged and overtopped following a storm surge, resulting in flooding

Arguments along the lines of “Well, this hasn’t happened in 100 years”, or “Bill has worked here all his life and he’s never seen it flood” are not valid when looking at these types of events

Therefore, from a screening perspective, events should only be ruled out if they are truly inconceivable. For example, if you have an inland site far upstream from an estuary, you don’t need to consider flooding from the sea or saltwater intrusion into your aquifer. But you may still need to consider river, surface, and groundwater flooding.

In summary, when looking at your Natech risks you need to ensure you are thinking about the following:

  • What is the risk to my site, as a whole, today?
  • How may site access, and thus emergency response, be impacted by the different events?
  • How may the risk evolve with climate change based on the baseline risk?
  • What measures can I implement to help mitigate events, and will these have a negative impact on safety and/or environmental risk?
  • Is the event credible and am I ruling it out for the correct reasons?

So, what next?

What can you do to address these risks? Here are helpful next steps you may wish to consider:

  • Raise the topic (and profile) of natural hazard risks at an upcoming team meeting. For example, you could ask your team whether they have knowledge of what sorts of incidents have occurred in the past, both on your site and more broadly. This could lead on to questions and discussion on what sorts of natural hazards your site is at risk from. The following list can be used as a prompt:
    – flooding
    – high temperatures, including heatwaves, prolonged dry weather, and drought
    – low temperatures, including heavy snowfall, ice, and prolonged cold
    – wildfires
    – windstorms 
    – lightning and thunderstorms, including hail 
    – erosion, including coastal erosion 
    – subsidence 
  • Follow this up with a site-walk, dedicated to considering natural hazards and identifying areas of your site that could be vulnerable, both now and in the future with climate change. Are you able to identify any areas where improvements could be made? For example, are there any areas where surface water is pooling? Is this near equipment or switch rooms?
  • Have discussions with team members who spend all their time on site. What is their experience when it’s too hot, or icy, or in heavy rainfall? How is this managed?
  • Share reports or videos (eg those produced by the US Chemical Safety Board) which summarise notable natural hazard-induced accidents, one example being the 2017 Arkema incident in Texas1

These initial actions should form the first steps in developing a methodical approach to managing risks to your site, risks that don’t only threaten safety and the environment, but businesses and livelihoods too.



Article by Aimee Russell

Senior analyst at RAS Limited

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