Tag Archives: fatality

Crane Collapse In High Winds Kills One in NYC

By ThinkReliability Staff

A crane collapsed in New York City on February 5, 2016 killing one, injuring three, and damaging two city blocks. While an investigation is underway and the causes of the crane collapse have not yet been determined, the city has already implemented new rules to make crane operations safer. We can examine the potential cause-and-effect relationships that led to the issue in a Cause Map, or visual root cause analysis.

We begin by capturing the what, when and where of the incident within a problem outline. The crane collapse occurred February 5 at about 8:30 a.m. Anything that is different or unusual at the time of an incident should also be noted on the outline and an important difference on February 5 was the accelerating winds. The crane that collapsed was a crawler crane, and at the time of the collapse, workers were in the process of securing the crane because of the high winds. This was as expected. Says New York City Mayor Bill de Blasio, “The workers on Friday morning did not begin work on the site, but immediately seeing the winds, made the move to secure the crane, so their timing was appropriate. Upon arrival, they immediately determined the need to secure the crane.”

The impact to the goals as a result of the incident are also captured in the problem outline. In this case, the safety goal was impacted due to the death, as well as injuries. The environmental goal was impacted by water leaks resulting from damage. Customer service (looking at the citizens of New York City as customers) is impacted due to closures. Production is impacted because 418 additional cranes were secured as a result of the incident. Property impacts includes damage to the crane, as well as two city blocks. The labor goal was impacted because of the time required for the response and removal of the damaged crane. It’s also important to capture the frequency of similar events. OSHA reports it has investigated 13 fatal crane accidents in the last 5 years. (There was a crane collapse in New York City in 2008 that resulted in 4 deaths. Click here to see our previous blog on this topic.)

Once the impacts to the goals have been captured, the analysis begins with one of these goals, which is an effect. Asking “why” questions allows the development of cause-and-effect relationships. In this case, the fatality and injuries resulted from the collapse of a crane. It also resulted from people being in the area of the crane collapse. Both of these causes are required (the fatality and injuries would not have occurred if the crane had not collapsed, or if people had not been in the area) so they are listed vertically and joined with “AND”.

People were in the area where the crane collapsed because the area was inadequately secured. This is likely because construction workers were responsible for securing the area, as well as securing the crane. The reasons for the crane collapse are unknown. However, the investigation will look at human error, structural and equipment problems, and impacts from high winds. While the cause has not been determined, it is considered likely that the wind played a role. The crane was not yet secured, as the workers were in the process of attempting to secure it. It was not required to be secured because city regulations limit operation of cranes when wind is above 30 miles per hour(mph), or if there are gusts greater than 40 mph. The crane operators were working under a limit of 25 mph, as sometimes manufacturers use stricter limits. The forecast did not indicate that winds would be greater than 25 mph that day.

As a result of the incident, Mayor de Blasio put into place immediate and temporary rules regarding crane operation. These rules will be in place until a task force provides updated recommendations within 90 days. Uniformed personnel will assist with enforcing closures associated with crane use. Crane operations are limited to wind speeds less than 30 mph (or gusts up to 40 mph). A city sweep and increased fines were also put into place to ensure the updated regulations are followed.

To view a one-page overview of the Outline, Cause Map and interim solutions, click on “Download PDF”.

Fatal Bridge Collapse Near Cincinnati

By Kim Smiley

On the evening of January 19, 2015, an overpass on Interstate 75 near Cincinnati collapsed, killing one and injuring another.  The overpass was undergoing construction when it unexpectedly collapsed onto the road below it, which was still open to traffic.

This incident can be analyzed by building a Cause Map, a visual root cause analysis, to intuitively lay out the many causes that contributed to an accident by showing the cause-and-effect relationships.  Understanding all the causes that played a role, as opposed to focusing on a single root cause, expands the potential solutions that can be considered and can lead to better problem prevention.  A Cause Map is built by asking “why” questions and documenting the answers.

In this example, a construction worker was operating an excavator on the overpass when it collapsed.  When the bridge collapsed the worker was crushed by the steel beams he was moving.   The additional weight of evacuator and steel beams on the overpass likely contributed to the collapse.   The overpass was being demolished as part of a project to remake this section of the Interstate and a portion of the overpass had already been removed.  The work that had been done appears to have made the structure of the bridge unstable, but the construction company was not aware of the potential danger so the worker was operating on top of the overpass and the road beneath it was still open to traffic.

A truck driver traveling under the overpass at the time of collapse suffered only minor injuries, but came within inches of being crushed by the bridge. It really was simple luck that no other vehicles were involved.  Had the collapse happened earlier in the day when there was more traffic, the number of fatalities may very well have been higher.  As investigators review this accident, one of the things they will need to review is the fact that the road below the bridge was open to traffic at the time of the collapse.  An additional relevant piece of information is that the construction company had financial incentives to keep the road open as much as possible because they would be fined for any amount of time that traffic was disrupted.

In addition to the safety impacts of this accident, the overpass collapse dramatically impacted traffic on a busy road with an estimated 200,000 vehicles traveling on it daily.  It took nearly a day to get all lanes of the interstate cleaned up and reopened to traffic.  No one wants to close roads unnecessarily and the goal of minimizing traffic is an excellent one, but it has to be balanced with safety.  The collapse of the overpass wasn’t an unforeseeable random accident and the demolition needs to be done in a safe manner.

Passengers trapped in smoke-filled metro train

By Kim Smiley

A standard commute quickly turned into a terrifying ordeal for passengers on a metro train in Washington, DC the afternoon of January 12, 2015.  Shortly after leaving a station, the train abruptly stopped and then quickly filled with thick smoke. One passenger died as a result of the incident and 84 more were treated for injuries, predominantly smoke inhalation.

This incident can be analyzed by building a Cause Map, a visual root cause analysis.  A Cause Map visually lays out the cause-and-effect relationships to show all the causes that contributed to an issue.  The first step in the Cause Mapping process is to define the problem by filling in an Outline with the basic background information as well as documenting how the issue impacts the overall goals.  For this example, the safety goal is clearly impacted by the passenger death and injuries.  A number of other goals should also be considered such as the schedule goal which was impacted by significant metro delays.  (To view an Outline and initial Cause Map for this issue, click on “Download PDF” above.)

So why were passengers injured and killed?  Passengers were trapped on the train and it filled with smoke.  It is unclear why the train wasn’t able to back up to the nearby station once the smoke formed and investigators are working to learn more.  (Open issues can be documented on the Cause Map with a question mark to indicate that more evidence is needed.)  There are also questions about the time emergency workers took to reach the train to aid in evacuation of passengers so this is another area that will require more information to fully understand. By some account, it took 40 minutes for firefighters to reach the trapped passengers.

Initial reports are that smoke was caused by an electrical arcing event, likely from the cables supporting the high voltage third rail used to power the trains. The specifics of what caused the arc are being investigated by the National Transportation Safety Board and will be released when the investigation is concluded.  What is known is that there was significant smoke caused by the arc, but no fire.  There have also been reports of water near the rails that may have been a factor in the arcing.

Eyewitness accounts of this incident are horrifying.  People had little information and didn’t know whether there was fire nearby at first.  They were told to remain on the train and await rescue, but the rescue took some time, which surely felt longer to the scared passengers.  It won’t be clear what solutions need to be implemented to prevent similar problems in the future until the investigation is complete, but I think we can agree that metro officials need to work to ensure passenger safety going forward.

Investigation Into the Fatal Crash of Commercial Space Vehicle is Underway

By Kim Smiley

On October 31, 2014, Virgin Galactic’s commercial space vehicle, SpaceShipTwo, tore apart over the Mojave Desert in California during its fourth rocket-powered test flight. One pilot was killed and the other seriously injured. An investigation is underway to determine exactly what caused the crash, but initial data indicates that the tail booms used to slow down the vehicle moved into the feathered position prematurely, increasing the aerodynamic force. This disaster has the potential to impact the emerging commercial space industry as regulators and potential passengers are reminded of the inherent dangers of space travel.

This issue can be analyzed by building a Cause Map, a visual method for performing a root cause analysis. An initial Cause Map can be built using the information that is currently available and then easily expanded as more data is known. The first step is to fill in an Outline with the basic background information of the incident. Additionally, the impacts to the overall goals are listed on the Outline to determine the scope of the issue. The Cause Map is then built by asking “why” questions.

Starting with the safety goal in this example: one pilot was killed and another was injured because a space vehicle was destroyed and they were onboard. (When two causes both contribute to an effect, they are both listed on the Cause Map and joined with an “and”.) SpaceShipTwo is designed to hold passengers, but this was a test flight to assess a new fuel so the pilots were the only people onboard. The space vehicle tore apart because the stress on the vehicle was greater than the strength of the vehicle. The final report on the accident will not be available for many months, but the initial findings indicate that the space vehicle experienced greater aerodynamic forces than expected.

The space vehicle used tail booms that were shifted into a feathered position to increase drag and reduce speed prior to landing. Video shows the co-pilot releasing the lever that unlocked the tail booms earlier than expected while the vehicle was still accelerating. It’s unclear at this time why he released the lever. The tail booms were not designed to move when unlocked and a second lever controls movement, but investigators speculate that the aerodynamic forces on the space vehicle while it was still accelerating caused them to lift up into the feathered position once they were unlocked. The vehicle disintegrated seconds after the tail booms shifted position, likely because of the aerodynamic forces in play.

After the final report is released, the Cause Map can be expanded to include the additional information. To view a high level Cause Map of this accident, click on “Download PDF” above.

1 Dead and 27 Hospitalized from Carbon Monoxide at Restaurant

By Holly Maher

On Saturday evening, February 22, 2014, 1 person died and 27 others were hospitalized due to carbon monoxide poisoning.  The individuals were exposed to high levels of carbon monoxide that had built up in the basement of a restaurant.  The restaurant was evacuated and subsequently closed until the location could be deemed safe and the water heater, located in the basement, was inspected and cleared for safe operation.

So what caused the fatality and 27 hospitalizations?  We start by asking “why” questions and documenting the answers to visually lay out all the causes that contributed to the incident.  The cause and effect relationships lay out from left to right.

In this example, the 1 fatality and 27 hospitalizations occurred because of an exposure to high levels of carbon monoxide gas, which is poisonous.  The exposure to high levels of carbon monoxide gas was caused not only by the high levels of carbon monoxide gas being present, but also because the restaurant employees and emergency responders were unaware of the high levels of carbon monoxide gas.

Let’s first ask why there were high levels of carbon monoxide present.  This was due to carbon monoxide gas being released into the basement of the restaurant. The carbon monoxide gas was released into the basement because there was carbon monoxide in the water heater flue gas and because the flue gas pipe, intended to direct the flue gas to the outside atmosphere, was damaged.  The carbon monoxide was present in the flue gas because of incomplete combustion in the water heater.  At this point in the investigation, we don’t have any further information.  This can be indicated as a follow-up point on the cause map using a question mark.  We have also identified the reason for the flue gas pipe damage as a question mark, as we do not currently have the exact failure mechanism (physical damage, corrosion, etc.) for the flue gas pipe.  What we can identify as one of the causes of the flue gas pipe failure is an ineffective inspection process.  How do we know the inspection process was ineffective?  Because we didn’t catch the failure before it happened, which is the whole point of requiring periodic inspections.  This water heater had passed its annual inspection in March of 2013 and was due again in March 2014.

If we now ask the question, why were the employees unaware of the high levels of carbon monoxide present, we can identify that not only is carbon monoxide colorless and odorless, but also there was no carbon monoxide detector present in the restaurant.  There was no carbon monoxide detector installed because it is not legally required by state or local codes.  The regulations only require carbon monoxide detectors to be installed in residences or businesses where people sleep, i.e. hotels.

Once all the causes of the fatality and hospitalizations have been identified, possible solutions to prevent the incident from happening again can be brainstormed.  Although we still have open questions in this investigation, we can already see some possible ways to mitigate this risk going forward.  One possible solution would be to legally require carbon monoxide detectors in restaurants.  This would have alerted both employees and responders of the hazard present.  Another possible solution would be to require more frequent inspections of this type of combustion equipment.

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


Volunteer Killed in Helicopter Fall

By ThinkReliability Staff

On September 12, 2013, the California National Guard invited Shane Krogen, the executive director of the High Sierra Volunteer Trail Crew and the U.S. Forest Service’s Regional Forester’s Volunteer of the Year for 2012, to assist in the reclamation effort of a portion of the Sequoia National Forest where a marijuana crop had been removed three weeks earlier.  Because the terrain in the area was steep, the team was to be lowered from a helicopter into the area.

After Mr. Krogen left the helicopter to be lowered, an equipment failure caused the volunteer to fall 40 feet.  He later died from blunt force trauma injuries. The Air Force’s report on the incident, which was released in January, determined that Mr. Krogen had been improperly harnessed.  The report also found that he should have never been invited on the flight.

To show the combination of factors that resulted in the death of the volunteer, we can capture the information from the Air Force report in a Cause Map, or visual root cause analysis.  First it’s important to determine the impacts to the goals.  In this case, Mr. Krogen’s death is an impact to the safety goal, and of primary consideration.  Additionally, the improper harnessing can be considered an impact to the customer service goal, as Mr. Krogen was dependent on the expertise of National Guard personnel to ensure he was properly outfitted.  Because it was contrary to Air Force regulations, which say civilian volunteers cannot be passengers on counter-drug operations, the fact that Mr. Krogen was allowed on the flight can be considered an impact to the regulatory goal.  Lastly, the time spend performing the investigation impacts the labor goal because of the resources used during the investigation.

Beginning with the impacted goal of primary concern – the safety goal – asking “Why” questions allows for the determination of causes that resulted in the impacted goal (the end effect).   In this case, Mr. Kroger died of blunt force trauma injuries from falling 40 feet.  He fell 40 feet because he was being lowered from a helicopter and his rigging failed.  He was being lowered from a helicopter to aid in reclamation efforts and because the terrain was too steep for the helicopter to land.

The rigging failure resulted from the failure of a D-ring which was used to connect the harness to the hoist.  Specifically, the D-ring was not strong enough to handle the weight of a person being lowered on it.  This is because the hoist was connected to Mr. Krogen’s personal, plastic D-ring instead of a government-issued, load-bearing metal D-ring.  After Mr. Krogen mistakenly connected the wrong D-ring, his rigging was checked by National Guard personnel.  The airman doing the checking didn’t notice the mistake, likely because of the proximity of the two D-rings and the fact that Mr. Krogen was wearing his own tactical vest, loaded with equipment, over the harness to which the metal D-ring was connected.

I think Mark Thompson sums up the incident best in his article for Time:   “The death of Shane Krogen, executive director of the High Sierra Volunteer Trail Crew, last summer in the Sequoia National Forest, just south of Yosemite National Park, was a tragedy. But it was an entirely preventable one.  It stands as a reminder of how dangerous military missions can be, and on the importance of a second set of eyes to make sure that potentially deadly errors, whenever possible, are reviewed and reversed before it is too late.”

To view the Outline and Cause Map, please click “Download PDF” above.  Or click here to read more.

Improper Fireplace Installation Results in Firefighter’s Death

By Mark Galley

While battling a fire in a mansion in Hollywood Hills, California on February 16, 2011, a firefighter was killed (and 5 others seriously injured) when the roof collapsed.  As a result of the firefighter’s death, the owner/ architect of the home was convicted of involuntary manslaughter.  He is scheduled to serve 6 months and then will be deported.

The fire wasn’t arson, but the owner/ architect was considered responsible due to the installation of an outdoor-only fireplace on the top floor of his home.  Because of the legal issues surrounding this case, it’s important to carefully determine and clearly present all of the causes that led to the fire and the firefighter’s death.

We can capture information related to this issue within a Cause Map, or visual root cause analysis.  A Cause Map begins with the impacted goals, allowing a clear accounting of the effects from the issue.  The firefighter’s death is an impact to the safety goal, as are the injuries to the other firefighters.  Impacts to the safety goal are the primary focus of any investigation, but we will capture the other impacted goals as well.  In this case, the regulatory goal was impacted due to the non-compliant fireplace, the non-compliance being missed during inspection, and the prison sentence for the architect/owner.  Additionally the loss of the home and the time and effort put into firefighting and the subsequent trial impact the property and labor/time goals.

Once the impacts to the goals are determined, asking “why” questions begins to develop the cause-and-effect relationships that resulted in those impacts.  A Cause Map can start simple – in this example, the safety goal was impacted due to the death of a firefighter.  Why? Because the ceiling collapsed.  Why? Because the house was on fire.  Why? Because heat ignited flammable building materials.

Though this analysis is accurate, it’s certainly not complete.  More detail can be added to the Cause Map until the issue is adequately understood and all causes are included in the analysis.  Detail can be added by asking more “why” questions – the heat ignited flammable building materials because an outdoor-only fireplace was improperly used inside the house.  Causes can also be added by considering causes that both had to occur in order for the effect to happen.  The firefighter was killed when the ceiling collapsed AND the firefighter was beneath the ceiling, fighting the fire.  Had the ceiling collapsed but the firefighters not been inside, the firefighter would not have been killed by the ceiling collapse.

Detail can also be added between causes to provide more clarify.  In this case, the ceiling collapse was not directly caused by high heat.  Instead, the high heat activated and melted the sprinkler system, resulting in a buildup of water that caused the ceiling collapse.  The other goals that were impacted should also be added to the Cause Map, which may result in more causes.  In this case, the improperly installed fireplace was missed by the building inspector, which is an impact to the regulatory goal.  The reason it was missed was debated during the trial, but changes to the inspection process may result that would make this type of incident less likely, ideally reducing the risk to firefighters and home owners.

An incident analysis should have enough detail to lead to solutions that will reduce the risk of recurrence of the impacted goals.  As I mentioned previously, solutions from the perspective of the building inspectors may be to look specifically for issues on fireplaces that could lead to these types of fires.  Ideally, a way to determine if a sprinkler system was malfunctioning and leading to water collection could be developed that could reduce the risk to firefighters.  For homeowners, this incident should stand as a reminder that outdoor-only heat sources such as fireplaces are outdoor-only for a reason.

Seat Belts: A Simple Solution That is Still Underused

By ThinkReliability Staff

One of the most frequent questions we get is “What’s the root cause?”  The problem with that question is that there is never just one, root cause.  Rather, the ‘root cause” should be thought of as a system of causes, much like the roots of most plants are a system.  But the idea of a root cause is attractive – only one thing to find, analyze and solve.  There are a few, rare situations that are almost one, root cause.  One of them is the use of seat belts.

Not wearing a seat belt can cause all kinds of problems, in any kind of vehicle.  In passenger vehicles, seat belts saved more than 75,000 lives from 2004 to 2008, according to the National highway Traffic Safety Administration (NHTSA).  Over that same period, more than 26,000 more lives WOULD have been saved if everyone wore a seat belt.  Unfortunately, not everyone does.  According to the National Safety Council (NSC), seat belt use varies by the type of vehicle but is around 80%.

It’s not just cars that are at issue.  On March 29, 2013, a man was thrown from an experimental plane and killed when the canopy came off.  He wasn’t wearing a seat belt, which would have almost certainly kept him from being ejected – and killed.  Although the FAA requires that safety belts be fastened while crewmembers are at their duty  stations, the pilot, who was killed, had unfastened his safety belt to troubleshoot problems with the battery and apparently did not successfully re-fasten the belt.   (The instructor was not ejected and was able to safely land the plane.)

Although states are trying with mandatory seat belt laws, you can’t force everyone to wear a seat belt all the time.  However, there are many actions being taken to try and increase seat belt use.  As previously mentioned, states are increasing laws and enforcement of requiring seat belt use for all passengers.  Car manufacturers have added warning systems that encourage seat belt use for drivers, and front seat passengers.

Seat belt use (percentage-wise) is lowest among those who have just gotten their license.  As a parent, requiring use of a seat belt every time, every trip, for every passenger can help reduce the risk to your child and his or her passengers.  As an employer, vehicle crashes can have a serious impact to your organization. According to the Occupational Safety and Health Administration (OSHA), motor vehicle accidents are a leading cause of death and injury and cost employers $60 billion annually.  All employers should have a driver safety program.   (Tips on establishing a driver safety program can be found here.)

There is no question that deaths from traffic accidents are a major concern – to everyone.  According to the NHTSA, “seat belts are the most effective traffic safety device for preventing death and injury.”  Because of the effectiveness of seat belts, the  risk of deaths from vehicle accidents, it’s no stretch to say that buckling your seat belt – and getting everyone in your vehicle, family, and organization to do the same – may well be the most important thing you do today.

To view the Outline and Cause Map for the plane ejection, please click “Download PDF” above.  If you’re curious why school buses do not have seat belts, read our previous blog.  Or click here to  read more:

This incident





Natural Gas Explosion Kills One in Kansas City

By ThinkReliability Staff

A natural gas leak at a business plaza in Kansas City was reported to the Fire Department just prior to 5 pm on February 19, 2013.  However, the area was not evacuated until just prior to an explosion that left 1 dead and 15 injured.  The leaking gas was not shut off until 3 hours after the report.

The causes that resulted in this tragedy can be examined within a Cause Map, or visual root cause analysis.  The analysis begins by determining which goals were impacted in a problem outline, which captures the what, when and where of the incident, as well as the impact to the goals.  In this case, the safety goal was impacted due to the fatality and injuries.  The environmental goal was impacted due to the natural gas leak and the customer service goal was impacted due to an ineffective evacuation.  (How do we know it was ineffective?  Because people were still present in a building that exploded due to a gas leak that was known for almost an hour, although the timing of the ordered evacuation is not known.)  Additionally, the property goal was impacted due to the destruction of restaurant, which was the site of the explosion, and damage to adjoining properties.  Lastly, the labor goal is impacted due to the investigation by state utility regulators, which is expected to take months of painstaking work to add detail to the causes which are already known.

Once these goals have been determined, we begin with an impacted goal and ask “Why” questions to add detail to the analysis.  The safety goal was impacted due to the death and injuries.  These occurred because of the explosion AND because people were in the proximity of the explosion.  Had the explosion occurred after a complete evacuation, the injuries would have been substantially reduced, if not completely prevented, although the property goals would have still been impacted.

An evacuation ws not ordered by the fire department, who deferred to the utility company.  The utility company was slow in determining that an evacuation was needed.  There was general confusion about the responsibility for determining an evacuation.   Per the city’s emergency response plan, the Incident Commander is responsible for evacuations.  However, no Incident Commander  was named on-scene until after the explosion, as it was determined that no incident yet existed.  Because quite a bit of flexibility is generally needed in determining whether an evacuation is needed (as an evacuation itself can be dangerous), the emergency response plan is necessary somewhat confusing (in this case, contained in a 90-page document).

The explosion itself resulted from an unknown heat source within the restaurant igniting leaked natural gas.  The natural gas was leaking as a result of being struck by a boring machine being used to install fiber-optic cable in the area.  It was later determined that the contractor did not have the necessary permit for the work, though it’s not clear if that led to confusion on the location of the gas lines, or if they were mislabeled, or if it’s just that it’s really difficult to see lines when digging deep trenches using a boring machine.

The extent and probability of an explosion is related to the volume of gas released during a leak.  Had the gas been turned off earlier, the explosion might have been avoided, or lessened, reducing the impacts to all the goals.  The gas was not turned off before the explosion, and after the explosion continuing fires made the shut-off locations difficult to reach.  it’s not clear why the gas wasn’t turned off immediately, though the choice to do so  does result in other impacts, such as the loss of gas to other customers.  In cases where the true extent of the issue is not known, it is difficult to make these decisions and limit potential effects.

Because one of the issues was not knowing the extent of the leak, it has been suggested that all fire department trucks be equipped with natural gas sniffers.    Additionally, an update to the city’s evacuation protocol has been called for that would, among other changes, give authority to the first arriving public safety official  to order an evacuation, resulting some of the confusion that led to the tragedy in Kansas City.

As this example shows, it’s not only attempting to prevent these events that’s important but also ensuring that emergency plans and protocol clearly define actions to be taken as well as responsible parties.  Drills and simulations can ensure that the plans and protocols are even more effective.   This is true not only for cities and fire departments but for any organization tasked with the safety of people . . . which is to say, all of them.

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

Supply of Disposable Diapers Threatened by Explosion at Chemical Plant

By Kim Smiley

On September 29, 2012, an explosion at a chemical plant in Japan killed a fire fighter, injured 35 others and did significantly damage.  Chemicals produced at the plant are used in disposable diapers.  The damaged plant will be inoperable for the foreseeable future, which will likely impact the global supply of disposable diapers, a thought that strikes fear in the hearts of many parents of small children.

This incident can be analyzed by building a Cause Map, an intuitive, visual format for performing a root cause analysis.  The first step in building a Cause Map is to identify which goals were affected.  In this case, the safety goal is obviously impacted since there was a fatality and injuries.  The production goal is also a major consideration since the supply of disposable diapers is threatened because the plant will be unable to produce chemicals for a significant amount of time.  The next step is to ask “why” questions to add additional boxes to the Cause Map.

Starting with the safety goal first, we would ask “why” there was a fatality and injuries.  In this example, people were hurt because there was a fire at a chemical plant.  The fire occurred because a tank exploded and it was near other tanks full of flammable chemicals.  The tank exploded because the temperature inside the tank was increasing and it wasn’t cooled in time.  It isn’t clear yet why the temperature was increasing inside the tank, but investigators are working to find the cause.  Once it is known, it can be added to the Cause Map.

At the time of the explosion, efforts were underway to cool off the tank, but they weren’t effective.  Firefighters were working to spray down the tank with cool water to help lower the temperature, but the temperature rose too quickly.  This is also a cause of the fatality.  A fireman was working to connect spray lines near the tank at the time it exploded and he was sprayed with hot chemicals.  Other injuries occurred at the time of explosion and others were sustained during the effort to fight the fire.  It’s possible that one of the reasons that the workers were unable to cool the tank was that the usual method of cooling the tank, injecting nitrogen to decrease the oxygen and control the chemical reactions occurring, might not have been functioning properly.  This is another area that can be clarified on the Cause Map as more information is known.

Looking at the production goal now, a potential shortage of disposable diapers may occur as a result of this accident because the plant produced a significant amount of a chemical used in manufacturing diapers.  This plant produced 20% of world’s supply of one chemical in particular needed for diapers.  Combine this with the fact that the other plants manufacturing this chemical are already operating at maximum capacity and the supply will likely be less than the demand.

The final step in the process is to use the Cause Map to develop solutions to help prevent similar problems from occurring in the future.  It’s premature to discuss specific solutions in this example since the investigation is still ongoing, but the initial Cause Map can easily be expanded and used when all the information is available.