Thursday, March 20, 2008

Chemical Incident Review – 3-20-08

Once again, since there have been no reported terrorist incidents at chemical facilities reported in the press, we will look at chemical accidents and incidents that have been reported. It has been a busy couple of weeks according to news reports, so we have lots to choose from. Remember, this is not being done to review safety, but rather to look at such incidents to see what they can teach us about security and mitigation.


In today’s review we will look more at the emergency response planning side of incidents. This planning is an integral part of the facility Site Security Plan. The purpose of a good emergency response plan is to mitigate the effects of an otherwise successful terrorist attack.


Tideflats Bleach Plant; Tacoma, WA


This incident actually took place over a year ago, but the Tacoma News Tribune had a detailed review of the Tacoma Fire Departments response to the spill of chlorine at the bleach plant. According to the article the Hazmat team generally responded well to the leak, but underestimated the amount of the leak. Other responders were exposed to the chlorine gas because they failed to anticipate a wind change.


Detailed evaluations like this should be done after every incident and drill. They should be required in the emergency response plan and should be done as soon after the event as practical. The requirement for post-event evaluations should include specific mention of updating the response plan and standard operating procedures based on the results of that evaluation.


Jacam Chemicals; Stirling, KS


The sounds of explosions coming from a chemical plant fire strike fear in the hearts of nearby residents and fire fighters alike. On March 14th sounds of explosions woke residents near the Jacam Chemical plant. Fortunately, no chemicals were involved in the explosion. Empty, sealed drums were located in an area of the plant where a small fire started. The heat from the fire caused the air pressure in the drums to increase to the point that the drums ruptured.


This is a typical problem that must be taken into account when facilities do their emergency response planning. Any time that chemicals are stored in sealed containers there is the possibility for those containers to become explosive devices if they are involved in a fire. Storage tanks, tank trucks and rail cars are typically equipped with pressure relief devices to prevent such pressure explosions. The same cannot be said for smaller shipping containers like cylinders, drums, and even totebins.


Flammable and even combustible liquids can be especially dangerous in these situations. As the head space pressure builds the container is going to fail at the weakest point in its structure. When the container explosively fails the heated liquid within will typically spread far and wide, spreading the fire as it goes. It is not unusual for containers to fail at the bottom, launching the container into the air, trailing flames, and adding projectile hazards to the situation.


Stolthaven New Orleans LLC; Braithwaite, LA


A storage tank containing fluorosilicic acid was found to be leaking through a 16” crack in a welded seam of the tank. The 50-gal/min leak was quickly filling the concrete diked area surrounding the tank. Unfortunately, fluorosilicic acid eats through concrete. Outside the immediate diked area were storage tanks containing other chemicals; tanks that could become compromised by the acid. To avoid the problem of additional tank damage, responders pumped the acid out of the diked area into the Mississippi River.


The emergency response plan must take into account what needs to be done after storage tanks leak or fail into a containment area. Reactions between the chemicals involved and the dike material should certainly be high on the list of what must be considered. It is not always possible to have dike material that is not subject to damage by chemical attack. In that case the facility must have an idea how long they can expect the dike to last and what actions will be required while the dike is still intact. Pumping hazardous chemicals into a river should probably not be first on that list.

No comments:

/* Use this with templates/template-twocol.html */