Combination of Gas Leak and Flare Could be Disastrous

By Angela Griffith

A leak from the Elgin platform in the north sea near Aberdeen has the potential to cause an explosion due to the proximity of the leak to the still-lit flare on the platform.  However, the wind is currently blowing gas away from the flare.  The potential for environmental damage is not as great as that of Deepwater Horizon because it is a surface, rather than underwater, leak.

Workers on the now-evacuated Elgin rig noticed the leak on March 25, 2012.  The rig was partially, then later fully, evacuated.  We can examine the causes of the environmental leak, as well as the potential for further damage, in a visual root cause analysis in the form of a Cause Map.  The Cause Map lays out the cause-and-effect relationships in a clear, intuitive way.

We begin with the impacts to the goals.  The safety goal is impacted because of the potential for an explosion.  The environmental goal is impacted due to the gas leak, estimated to be approximately 200 cubic metres per day.  The customer service goal is impacted due to the loss of value of the owner corporation stock shares.  Production is currently shut down on the rig, leading  to an impact to the production goal.  The potential for an explosion could also cause catastrophic damage to the platform, which is an impact to the property goal.  Lastly, the evacuation of the platform is an impact to the labor goal.

In order for an explosion to occur, there must be fuel, oxygen, heat and confinement.  In this case, the oxygen is provided by the atmosphere, and the confinement is provided by the well itself.  The fuel is provided by the gas leak, believed to be entering from another non-producing well through a crack in the outer casing of the well, which was in the process of being plugged and abandoned.    The heat likely to cause the explosion is a flare on the platform.  The flare burns off excess gas from the platform and was not extinguished during the evacuation, as the priority was to remove the workers.

The flare is unable to be turned off remotely, but options for extinguishing the flare are being evaluated.  Other options being evaluated to stop the leak and reduce the potential for explosion include digging a relief well or killing the well that is currently leaking.  All options have the potential to be very expensive.

To view the Outline and Cause Map, please click “Download PDF” above.

School Leveled by Gas Explosion

By Kim Smiley

On March 18, 1937, the London School of New London, Texas was leveled by a huge explosion.  Unfortunately, many people were in the school on the afternoon of the explosion and an estimated 280 students, 15 teachers, 2 visitors and a school secretary were killed.  This tragedy remains the worst catastrophe to occur inside a school in American history.

The cause of this tragic incident can be investigated by building a Cause Map, a visual root cause analysis, which shows the cause and effect relationships between the different factors that contributed to the explosion.  A Cause Map begins by determining which goals were impacted and in this example the safety goal is the obvious focus.  Causes are then added to the Cause Map by asking “why” questions to add additional information.  In this example, the safety goal was impacted by the large number of fatalities.  The deaths occurred because the school was occupied and the school was destroyed.

The school was destroyed because there was a large natural gas explosion.  The explosion occurred because there was a large quantity of natural gas in the school and a shop teacher turned on a sander and created a spark.  The gas was in the school because there was a leak, there was a large quantity of gas was trapped in a void space under the school and the gas leak wasn’t detected.  The investigation into this incident was never able to decisively determine what caused the natural gas leak.  The void space was under the school because the school was built on a slope.  The leak wasn’t detected because the school was using untreated natural gas which is both invisible and odorless.

Why was the school using untreated natural gas?  The school was trying to save money by eliminating their heating bill.  The school was located near oil fields and had tapped into a nearby residue gas line to provide heat, saving approximately $300 dollars a month.  Using free untreated natural gas was a common practice in the region.  The gas company turned a blind eye since natural gas was considered a waste product of oil drilling that was just flared off.

The end result of using free, but untreated natural gas was that no one could detect that the school was filled with natural gas.  One spark and the whole school was destroyed along with many, many lives.

As a result of this horrendous accident, all natural gas in the United States is treated to have an odor, usually with mercaptan which smells like rotten eggs, so that leaks can be detected by smell.

Girder Fell on Car, Killing 3

by Kim Smiley

On May 15, 2004, a girder fell off an overpass and hit a car driving on the road below, killing all three occupants of the vehicle.  The National Transportation Safety Board (NTSB) investigated the incident to determine what caused the fatal accident.  The findings from the investigation can be used to build a Cause Map, a visual root cause analysis, which illustrates the causes that contributed to the accident.

In this example, the girder hit the car because it fell from an overpass and the car was driving on the road below it.  The girder was temporarily installed on the overpass because it was being used to add two additional lanes to the overpass.  The work was being performed at night in effort to minimize the impact on the heavy traffic that normally used the roads involved.  The workers believed the girder attached to the overpass was in a safe condition so they had opened the road beneath it to traffic.

The girder fell because it was inadequately fastened to the overpass.  The NTSB determined that the girder wasn’t installed plumb to the bridge and it was inadequately bolted to the bridge which allowed the girder to twist and ultimately fall.  The investigation also determined that the girder was inadequately fastened because the project wasn’t planned well.  The original work plan called for two girders to be spliced together and then fastened to the bridge, but a delay in work meant that the subcontractor was only able to get one girder up before the work was halted to allow the roads to be opened for morning rush hour.  (Weather delays postponed the work further and the single girder was fastened to the bridge for several days prior to falling.) There were also no Professional Engineers involved in the planning and no formal drawings created of how one girder would be fastened to the bridge.

The NTSB investigation also determined that the guidance that governed bracing was inadequate.  The language used was confusing and there was a lack of consistent standards.  The oversight of the contractor’s work was also inadequate since the inspector did not notice that the girder wasn’t secured adequately.

As a result of this investigation, the NTSB made several specific suggestions to revise bracing standards to improve clarity.

To view a high level Cause Map of this incident, click “Download PDF” above.

Deadly Train Collision in Poland

By Kim Smiley

On March 4, 2012, two passenger trains collided head-on near Szczekociny, Poland killing 16 and injuring 58.  It was Poland’s deadliest train crash in 20 years.

An investigation is underway to determine what caused the deadly accident, but an initial Cause Map can be built now and more details can be added as information becomes available.  A Cause Map is a visual root cause analysis format.  The first step in the process is to determine which organizational goals were not met and in this example the obvious goal to focus on is the safety goal.

The safety goal wasn’t met because there were fatalities and injuries.  This occurred when two trains crashed because they were traveling on the same track in opposite directions.  It’s not clear exactly how the trains ended up on the same track, but it appears human error was involved since prosecutors have announced plans to charge a controller for unintentionally causing the accident.  Media reports have also stated that the routing mechanism for one of the trains was set incorrectly so that it was sent down the wrong track and into the path of the other train.  As with any investigation that leads to human error, more information will be needed about why the mistake was made in order to fully understand why the accident occurred and determine what would be needed to prevent a similar one in the future.  In this case, we can also assume that the accident was caused by inadequate oversight of the controller or lack of a double check of the mechanisms because an ideal system won’t allow one single mistake to result in a deadly accident.

Another fact worth considering is that the rail system in Poland is in the midst of a massive modernization effort.  Poland’s rail system is being modernized to prepare for the huge crowds expected to travel to the Euro 2012 soccer championship this July.  The modernization effort has been possible in part because of subsidies offered by the European Union, which Poland joined in 2004.  As part of the modernization, more connections have been added and more trains have been running on the track where the accident occurred.  It isn’t clear yet if any of the changes contributed to the accident, but any recent changes to a system are worth reviewing during an accident investigation.

As more information is found during the investigation, the causes can easily be incorporated into the Cause Map to capture as much detail as needed.  To view a high level Cause Map, click “download PDF” above.

Cruise Ship Loses Power

By Kim Smiley

Part of the excitement involved in passenger cruises is access to remote areas of the world.  However, when a ship runs in to trouble, that remoteness can result in extremely difficult conditions.  This was the case on the Costa Allegra, which suffered an engine room fire in the Indian Ocean.

Passengers aboard the Costa Allegra experienced sub-standard conditions when the ship lost power and propulsion due to an engine room fire.  During the three days while the ship was being towed to land, there was no air conditioning, lighting, or running water.  Food and drinking water were provided by helicopter.

We can examine the causes and effects of this issue in a Cause Map, or visual root cause analysis.  With the Cause Mapping process, we begin by examining the impact to the goals.  Namely, when the incident occurred, which of the organization’s goals were not met?  In this case, although there appeared to be no injuries resulting from the fire itself (although some passengers may have become ill during the resulting conditions) there was the potential for severe injury resulting from the fire and then the lack of power that resulted.   Additionally, the customer service goal was impacted by the lack of running water, air conditioning, and lighting.  The schedule goal was impacted because the ship needed to be towed for 3 days.  The property goal was impacted due to the damage to the ship from the fire, and the labor goal was impacted due to the need for the ship’s crew to stand guard against pirate attack.

Once we’ve determined the goals that were impacted, we can use them as a basis for our map, and ask “Why” questions to add more detail.   Here, an engine room fire on the ship resulted in the loss of ship power, causing the loss of air conditioning, lighting and running water, and the loss of ability for the ship to propel itself, necessitating a tow.  The length of the tow is also affected by the type of ship doing the towing.  In this case, the first ship to arrive to the aid of the Costa Allegra was a fishing vessel.   Although tugboats later arrived, the Costa Allegra requested that the fishing vessel continue the tow, although it is believed that the tugboats would have been able to speed up the tow, possibly resulting in the ship arriving as much as 12 hours earlier.  The cruise ship company has stated that the tow was not changed in consideration of the consistency of the voyage for the passengers but there are also potentially financial considerations.  Assistance to people at sea is not paid, but assistance to ships is.  Thus, the fishing vessel actually entered into a contract with the cruise ship for the tow.

Part of the reason that a fishing vessel was the first to arrive is that there is little maritime traffic in the area.  This is due to the remoteness of the area in which the cruise ship was traveling, as well as the risk of piracy.  This, of course, led to a constant armed guard on the disabled ship to protect from potential pirate attack.

The location to which the ship was towed also impacts the length of the tow.  It was determined that smaller ports closer to the location of the disabled Costa Allegra could not accommodate the large number of passengers on the ship, so the ship was towed to an island of Seychelles.

The cause of the fire itself is still under investigation, although it is believed that an electrical fault is a likely cause and that arson is not likely.  As more information becomes available, we can add that information to the Cause Map as well.

To view the Outline and Cause Map, please click “Download PDF” above.