Monday, May 28, 2018

CSB Releases Final Report on Arkema Fire

Last week the Chemical Safety Board (CSB) released their final report [.PDF download] on the Arkema chemical facility fire that occurred as a result of the flooding during Hurricane Harvey last year. The detailed report is lengthy and detailed and deserves the attention of safety professionals, but the Executive Summary is surprisingly detailed and should be read by everyone in the chemical industry. And, as usual, the CSB has produced another excellent video providing a good review of the incident. I cannot say enough good things about CSB incident videos.

High Points

I am not going to go into much detail here because I do not want to give anyone an excuse for not reading the report, but there are a couple of things that need to be highlighted.

First, the Arkema facility team did do a good job in analyzing the safety issues and preparing for the storm. While the CSB report does raise some specific questions and identifies some things that could have been done better, the pre-planning and on-site reactive measures that were taken demonstrate that Arkema was proactive and properly reactive regarding this incident.

Second, the police officers that were exposed to smoke from the decomposition fires during this incident were well within the mile and a half evacuation zone established around the plant when the plant lost the ability to cool the organic peroxides. This was due to the fact that the road outside the plant fence was kept open during much of the evacuation because it was one of the few remaining accessible roads in the area. The affected officers were patrolling that road to monitor the potential effects of the Arkema incident on users of that route.

Finally, the flooding levels seen in the area of the plant exceeded the ‘500-year flood’ level. While it appears that Arkema was not aware of what the 100- and 500-year flood levels were for the facility, this does demonstrate the magnitude of the disaster that was the proximate cause of the Arkema incident.


The CSB makes the point that all of the protective measure put in place to prevent the organic peroxides from reaching their self-accelerating decomposition temperature (SADT) failed from a common cause; the flooding at the site. They then go on to recommend (Recommendation 2017-08-I-TX-R1) that the Arkema Facility:

“Reduce flood risk to as low as reasonably practicable (ALARP). Ensure that any safeguards for flooding meet independent layer of protection requirements.”

The fact that Arkema was not aware that a significant part of the facility was within the “500-year” flood plain is a point well taken, but it is not clear that before this incident anyone would have considered preparing for a 500-year flood to be a reasonable standard for preparedness.

Having said that, this incident and the whole Harvey flood calls into question the efficacy of the use of historical flood data in predicting future flooding. Sections 12 and 13 of the report deal with the issue of increasing risks related to ‘extreme weather’ events while being very careful to avoid any discussion of climate change. While the CSB is an independent agency not directly responsive to the Trump Administration (Could that have anything to do with the attempts to defund the organization?) it appears that the agency was very careful to avoid getting caught up in that controversy.

Unfortunately, anyone with a modicum of intellectual honesty has to admit that there has been an ongoing increase in the severity of rain events in the southeast (and along the Texas and Louisiana coast in particular) in recent history. And, that increase is significantly outside of the historic norms. While there may be some room for debate as to the cause of this recent change, the fact that the change exists cannot be ignored. The hard part, however, is going to try to determine what the 500-year flood plain is in the current reality.

Now, I suspect that for political reasons, the FEMA flood maps for the area flooded during Hurricane Harvey will not reflect the fact that the areas flooded now represent the defacto 100-year flood plain, but planners, specifically including emergency response planners, will have to accept that as the current reality.

One final note here worthy of consideration by chemical facility planners (and I will be taking this up in more detail in a future blog post) is the fact that the CSB recommendations do not limit themselves to extreme flooding events. In the Executive Summary (though carefully missing from the official recommendations in the report) the CSB also recommends that (pg 8):

“Seismic hazard maps should be evaluated to determine the potential risk of earthquake. Risk of other extreme weather events such as lightning strikes and high wind events should also be considered.”

1 comment:

Jake Brodsky said...

Here's what I see: What SIL rating did the equipment have to prevent reaching SADT?

If it was SIL2 then we're looking for environmental construction methods that also meet SIL2. So a Probability of Failure on Demand (PFD) would be somewhere between 1% and 0.1%. The criterion I would use in that case is a 500 year storm. That's a 0.2% chance a storm like that would occur in a given year.

This was worse than the criterion.

Frankly, everything has risks. The risk of sending all that stuff down the road while it is so heavily clogged with traffic is also very significant.

I think Arkema did everything that anyone could have expected of them. I rarely ever find myself disagreeing with the CSB. But the fact is, these people were doing everything they could with what they had. At some point, people run out of options.

So the social question is how many Layers of Protection Analysis are they obligated to use? Is it reasonable to expect SIL3 in an application like this, while the transportation risks are even higher?.

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