Tag Archives: safety

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The Solution to America’s Most Unexpectedly Dangerous Mammal

By ThinkReliability Staff

It’s hard to imagine that the mammal responsible for over 200 human deaths in America each year is the cute, cuddly…. deer.  These beautiful and seemingly harmless animals are hardly malicious.  Instead, they are in the wrong place at the wrong time, resulting in more than one million deer / vehicle collisions each year.  While the drivers have partial responsibility in these collisions, it seems that changes in the food chain have also contributed to this situation.   

In the 1800s, cougars (also called pumas or mountain lions) could be found roaming across the United States and Canada.  However, beginning in the early 1900s, states began implementing bounty programs enticing hunters to kill cougars.  The goal was to protect livestock and humans from these seemingly dangerous animals.  By the 1950s, the cougar population was primarily limited to areas west of the Rocky Mountains.  As the food chain predicts, the absence of a predator resulted in the overpopulation of its prey.  As the deer population increased, the probability for deer / vehicle collisions also increased.  

Expensive solutions have been considered to help decrease the collision rate, including deer culling, contraception and highway crossings.  However, it seems that nature may now be working towards its own natural solution.  As the bounty programs were removed in the 1960s and 1970s, the cougars have slowly begun migrating back towards the east.  A recent study published in Conservation Letters suggests that repopulation of cougars in the Eastern portion of the US could prevent 708,600 deer / vehicle collisions and 155 deaths over the next 30 years.   (The original fear of cougars attacking humans seems unfounded.  According to The Cougar Network, “Cougars are a retreating animal and very wary of people. Within the United States and Canada since 1890, there have been less than 100 attacks on humans, with about 20 fatalities. Encountering a cougar, let alone being attacked, is incredibly rare.”) 

A Cause Map is a helpful tool to dissect the cause-and-effect relationships contributing to a problem or situation.   Starting with the goals that were impacted, the causes and effects can be linked to create a chain.   For this situation, we begin with the safety goal that is impacted by the many fatalities each year.  Asking ‘Why’ questions, we can dig deeper to understand what causes are behind the impacted goal.   

In this case, the fatalities are a result of car collisions with deer.  The collisions are due to two factors: the deer unexpectedly crossing the road and the fact that the driver didn’t see the deer in time to stop.  We can trace each of these causes one at a time, revealing more causes.  The deer unexpectedly crosses the road because deer are moving to new areas.  This is because deer are overcrowded and need to expand their habitat.  The overcrowding is due to the growing deer population, which is due to the decrease in natural deer predators.  This decrease is caused by the decline in the cougar population, which is a result of the bounty programs that were implemented in the early 1900s.  These bounty programs were motivated by fear that the cougars would endanger humans or livestock.   

Going back to the driver’s role in the situation, we see that the driver may not have seen the deer in time due to poor lighting because deer often travel at dawn or dusk, and the driver may not have been paying close enough attention perhaps because they were distracted.   A second goal, property, was also impacted in this situation because the vehicles are damaged or destroyed as a result of the collisions.   

The Cause Map is also helpful in that it allows us to document the evidence and potential solutions directly on the causes that they can impact.   For example, the statistics about the number of collisions each year, fatalities each year, and cougar population changes are included right below the causes that they support.   Similarly, possible solutions are added right above the causes that they can impact.  In this case, deer culling and contraception could help control the deer overcrowding, and special deer highway crossings could help mitigate the deer crossing the road unexpectedly.  However, nature’s solution seems to fit further back in the chain by impacting the cause that is the decrease in the cougar population.   Time will tell if this solution will, in fact, reduce the number of collisions and injuries as predicted. 

To view the initial Cause Map of this issue, click on “Download PDF” above.

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Experts warn that vehicles are vulnerable to cyberattacks

By Kim Smiley 

By now, you have probably heard of the “internet of things” and the growing concern about the number of things potentially vulnerable to cyberattacks as more and more everyday objects are designed to connect to the internet.  According to a new report by the Government Accountability Office (GAO), cyberattacks on vehicles should be added to the list of potential cybersecurity concerns.  It’s easy to see how bad a situation could quickly become if a hacker was able to gain control of a vehicle, especially while it was being driven.

A Cause Map, a visual root cause analysis, can be built to analyze the issue of the potential for cyberattacks on vehicles.  The first step in the Cause Mapping process is to define the problem by filling out an Outline with basic background information as well as how the problem impacts the overall goals.  The Cause Map is then built by starting at one of the goals and asking “why” questions to visually lay out the cause-and-effect relationships. 

In this example, the safety goal would be impacted because of the potential for injuries and fatalities. Why is there this potential? There is the possibility of car crashes caused by cyberattack on cars. Continuing down this path, cyberattacks on cars could happen because most modern car designs include advanced electronics that connect to outside networks and these electronics could be hacked.  Additionally, most of the computer systems in a car are somehow connected so gaining access to one electronic system can give hackers a doorway to access other systems in the car.

Hackers can gain access to systems in the car via direct access to the vehicle (by plugging into the on-board diagnostic port or the CD player) or, a scenario that may be even more frightening, they may be able to gain access remotely through a wireless network.  Researchers have shown that it is possible to gain remote access to cars because many modern car designs connect to outside networks and cars in general have limited cybersecurity built into them. Why cars don’t have better cybersecurity built into them is a more difficult question to answer, but it appears that the potential need for better security hadn’t been identified.

As of right now, the concern over potential cyberattacks on cars is mostly a theoretical one.  There have been no reports about injuries caused by a car being attacked.  There have been cases of cars being hacked, such as at Texas Auto Center in 2010 when a disgruntled ex-employee caused cars to honk their horns at odd hours and disabled starters, but there are few (if any) reports of cyberattacks on moving vehicles.  However, the threat is concerning enough that government agencies are determining the best way to respond to it. The National Highway Traffic Safety Administration established a new division in 2012 to focus on vehicle electronics, which includes cybersecurity. Ideally, possible cyberattacks should be considered and appropriate cybersecurity should be included into designs as more and more complexity is added to the electronics in vehicles, and objects ranging from pace-makers to refrigerators are designed to connect to wireless networks.

Root Cause Analysis - Incident Investigation

8 Injured by Arresting Cable Failure on Aircraft Carrier

By ThinkReliability Staff

An aircraft carrier is a pretty amazing thing. Essentially, it can launch planes from anywhere. But even though aircraft carriers are huge, they aren’t big enough for planes to take off or land in a normal method. The USS Dwight D. Eisenhower (CVN 69) has about 500′ for landing planes. In order for planes to be able to successfully land in that distance, it is equipped with an arresting wire system, which can stop a 54,000 lb. aircraft travelling 150 miles per hour in only two seconds and a 315′ landing area. This system consists of 4 arresting cables, which are made of wire rope coiled around hemp. These ropes are very thick and heavy and cause a significant risk to personnel safety if they are parted or detached.

This is what happened on March 18, 2016 while attempting to land an E-2C Hawkeye. An arresting cable came unhooked from the port side of the ship and struck a group of sailors on deck. At least 8 were injured, several of whom had to be airlifted off the ship for treatment. We will examine the details of this incident within a Cause Map, a visual form of root cause analysis.

The first step in any problem investigation is to define the problem. We capture the what, when, and where within a problem outline. Additionally, we capture the impacts to the goals. The injuries as well as the potential for death or even more serious injuries are impacts to the safety goal. Flight operations were shut down for two days, impacting both the mission and production/ schedule goal. The potential of the loss of or (serious damage to) the plane is an impact to the property goal. (In a testament to the skill of Navy pilots, the plane returned to Naval Station Norfolk without any crew injuries to the flight crew or significant damage to the plane.) The response and investigation are an impact to the labor goal. It’s also useful to capture the frequency of these types of incidents.   The Virginian-Pilot reports that there have been three arresting-gear related deaths and 12 major injuries since 1980.

The next step in the problem-solving process is to determine the cause-and-effect relationships that led to the impacted goals. Beginning with the safety goal, the injuries to the sailors resulted from being struck by an arresting cable. When a workplace injury results, it’s also important to capture the personal protective equipment (PPE) that may have impacted the magnitude of the injuries. In this case, all affected sailors were wearing appropriate PPE, including heavy-duty helmets, eye and ear protection. This is a cause of the injuries because had they NOT been wearing PPE, the injuries would have certainly been much more severe, or resulted in death.

The arresting cable struck the sailors because it came unhooked from the port side of the ship. The causes for the detachment of the cable have not been conclusively determined; however, a material failure results from a force on the material that is greater than the strength of the material. In this case the force on the arresting cable is from the landing plane. In this case, the pilot reported the plane “hit the cable all at once”, which could have provided more force than is typical. The strength of the cable and connection may have been impacted by age or use. However, arresting cables are designed to “catch” and slow planes at full power and are only used for a specific number of landings before being replaced.

Other impacted goals can be added to the Cause Map where appropriate (additional relationships may result). In this case, the potential damage to the plane resulted from the landing failure, which was caused by the detachment of the arresting cable AND because the arresting cable is needed to safely land a plane on an aircraft carrier.

The last step of the Cause Mapping process is to determine solutions to reduce the risk of the incident recurring. More investigation is needed to ensure that the cable and connection were correctly installed and maintained. If it is determined that there were issues with the connection and cable, the processes that lead to the errors will be improved. However, it is determined that the cable and connection met design criteria and the detachment resulted from the plane landing at an unusual angle, there may be no changes as a result of this investigation.

It seems unusual that an investigation that resulted in 8 injuries would result in no action items. However, solutions are based on achieving an appropriate level of risk. The acceptable level of risk in the military is necessarily higher than it is in most civilian workplaces in order to achieve desired missions. Returning to the frequency from the outline, these types of incidents are extremely rare. The US Navy currently has ten operational aircraft carrier (and an eleventh is on the way). These carriers launch thousands of planes each year yet over the last 36 years, there have been only 3 deaths and twelve major injuries associated with landing gear failures, performing a dangerous task in a dangerous environment. Additionally, in this case, PPE was successful in ensuring that all sailors survived and limiting injury to them.

To view the outline and Cause Map of this event, click on “Download PDF” above.

 

Root Cause Analysis - Incident Investigation

Is Having a Lockout/ Tagout (LOTO) Procedure Enough?

By Staff

The number of possible types of injuries occurring when performing work on energized equipment is impossible to count.  They can range from burns, to electrical shock, to crush injuries, to cuts/lacerations, and beyond.  In an effort to help eliminate some of these injuries, the OSHA standard for Control of Hazardous Energy (29 CFR 1910.147), more commonly known as lockout/tagout (LOTO), went into effect in 1989.  The purpose of the standard is to help companies establish the practices and procedures needed to prevent injury to workers when they are performing maintenance activities to equipment requiring an energy source.  Any company in violation of the standard is subject to a fine.  It is estimated that in 2013, there were approximately $14 million in federal and state fines, and lockout/tagout was the 5th most frequently violated standard in 2015.

However, the REAL goal of the standard is to keep people safe.  So how is the standard violated?  It can happen in many ways, but this blog takes a look at one specific incident to better understand  how it can happen.  This analysis is based on a case study presented in the article “Lockout/Tagout Accident Investigation” from the August 2014 issue of Occupational Health & Safety.

In this incident, several contractors were working on a project involving a particular switchgear.  Many of these contractors had performed lockout/tagout for the switchgear box related to the projects that they were working on.  After the work began, a worker from a different contractor was asked to clean out part of the switchgear.  Unfortunately, an arc flash occurred when he reached in the switchgear, resulting in burns to his hand and a blow-out injury to his knee.  Fortunately, the employee survived, recovered, and was able to return to his normal life.

A Cause Map can be built to analyze this issue.  The first step in Cause Mapping is to determine how the incident impacted the overall goals.  For this incident, the safety goal was the most obviously impacted goal due to the injuries that the worker sustained.  The goal is always for employees to leave the workplace in the same health in which they arrived.  Additionally, the regulatory goal was impacted since the injuries were severe enough that they were classified as recordable.

The Cause Map is a visual representation of the cause-and-effect relationships that contributed to the incident.  Starting with the impacted safety goal, ‘why’ questions can be asked to identify the key factors that caused the problem.  In this case, the injuries were caused by the fact that an arc flash occurred when the worker reached into the switchgear and he was not wearing personal protective equipment.  The worker was probably not wearing PPE because he thought that the switchgear was de-energized, and this was an effect of the fact that there were locks and tags already on the switchgear.  The arc flash was a result of the fact that the circuit breaker was energized when the worker reached in to clean it.  The circuit breaker was energized because of three factors: a different contractor had put it back in service the night before, the circuit was not tested by the worker, and the worker didn’t do his own lockout procedure.  Each of these problems can be further analyzed to reveal problems with communication, adding the task at the last minute and not including every task in a job safety analysis.

For this situation, and many like it, eliminating a cause anywhere on the map could have minimized the risk of the incident occurring.  For example, had the worker taken the time to put on protective equipment or test the circuit breaker, he might not have been injured.  Similarly, had the other contractors taken the time to update their locks/tags and ensure that they had communicated that the circuit had been reenergized to all interested parties, the worker might not have been injured.  This example demonstrates that having a lockout/tagout procedure is the first step in avoiding injuries.  Ensuring that the procedure is followed in combination with other safety standards is also important to minimize the risk of injury.

Root Cause Analysis - Incident Investigation

Why New Homes Burn Faster

By Kim Smiley

Screen Shot 2015-12-04 at 11.50.42 AMResearch has shown that new homes burn up to eight times faster than older homes.  What this means is that people have less time to get out of a house when a fire starts – a lot less time.  People living in older homes with traditional furnishings were estimated to have about 17 minutes to safely evacuate a home, but the time decreases to about three minutes in a home built with modern materials and furnished with newer, synthetic furniture.

Modern manufactured wood building materials have a lot of advantages. They are lighter, stronger and cheaper than using traditional wood materials, but these characteristics also mean they burn a lot faster.  Additionally, modern homes typically contain more potential fuel for fires. Many modern furnishings are manufactured using synthetics that contain hydrocarbons, which are a flammable petroleum product.  Furnishings manufactured with synthetic products will burn faster and hotter than traditional furnishings built using wood, cotton and down.  Most modern homes also just simply have more stuff in them that is potential fuel.

Other factors can also make modern homes more dangerous when a fire occurs. Many modern homes are open concept designs as opposed to more compartmentalized traditional designs.  Open spaces in a home can provide more oxygen for a fire to quickly grow.  Additionally, modern energy-efficient windows can help trap heat in a home when a fire starts and can lead to a fire spreading more rapidly. Changes in the way we live and build homes and furnishings have all contributed to modern homes building significantly faster, a potential danger that people need to be aware of so that they can work to keep themselves and their children safe.

The best way to protect yourself and your family is to prevent a fire from occurring in the first place.  Never leave candles burning unattended. Keep all potentially flammable items away from fireplaces and heaters. Don’t leave things on the stove unattended. During the holidays, make sure to keep Christmas trees well watered and away from heat sources and ensure candles are a safe distance from any potentially flammable objects.   These and other basic common sense steps really do prevent fires from occurring.

Of course there is no way to guarantee that a fire will never occur so every house needs working smoke detectors.  It is recommended that they are checked monthly to verify they are functional and that the batteries are changed regularly.  Most fatalities associated with home fires are in homes without working smoke detectors so it really is worth the time and effort to ensure they are kept in good working order.

To view a Cause Map, a visual root cause analysis of this issue, click on “Download PDF” above.

 

Root Cause Analysis - Incident Investigation

Interim Recommendations After Fatal Chemical Release

By ThinkReliability Staff

After a fatal chemical release on November 15, 2014 (see our previous blog for an initial analysis), the Chemical Safety Board (CSB) immediately sent an investigative team. The team spent seven months on-site. Prior to the release of the final report, the CSB has approved and released interim recommendations that will be addressed by the site as part of its restart.

Additional detail related to the causes of the incident was also released. As more information is obtained, the root cause analysis can be updated. The Cause Map, or visual root cause analysis, begins with the impacts to the organization’s goals. While multiple goals were impacted, in this update we’ll focus on the safety goal, which was impacted due to four fatalities.

Four workers died due to chemical asphyxiation. This occurred when methyl mercaptan was released and concentrated within a building. Two workers were in the building and were unable to get out. One of these workers made a distress call, to which four other workers responded. Two of the responding workers were also killed. (Details on the attempted rescue process, including personal protective equipment used, have not yet been released.) Although multiple gas detectors alarmed in the days prior to the incident, the building was not evacuated. The investigation found that the alarms were set above permissible exposure limits and did not provide effective warning to workers.

Methyl mercaptan was used at the facility to manufacture pesticide. Prior to the incident, water accessed the piping system. In the cold weather, the water and methyl mercaptan formed a solid, blocking the pipes. Just prior to the release, the blockage had been cleared. However, different workers, who were unaware the blockage had been cleared, opened valves in the system as previously instructed to deal with a pressure problem. Investigators found that the pressure relief system did not vent to a “safe” location but rather into the enclosed building. The CSB has recommended performing a site-wide pressure relief study to ensure compliance with codes and standards.

The building, which contained the methyl mercaptan piping, was enclosed and inadequately ventilated. The building had two ventilation fans, which were not operating.   Even though these fans were designed PSM critical equipment (meaning their failure could result in high consequence event), an urgent work order written the month prior had not been fulfilled. Even with both fans operating, preliminary calculations performed as part of the investigation determined the ventilation would still not have been adequate. The CSB has recommended an evaluation of the building design and ventilation system.

Although the designs for processes involving methyl isocyanate were updated after the Bhopal incident, the processes involving methyl mercaptan were not. The investigation has found that there was a general issue with control of hazards, specifically because non-routine operations were not considered as part of hazard analyses. The CSB has recommended conducting and implementing a “comprehensive, inherently safer design review” as well as developing an expedited schedule for other “robust, more detailed” process hazard analyses (PHAs).

Other recommendations may follow in the CSB’s final report, but these interim recommendations are expected to be implemented prior to the site’s restart, in order to ensure that workers are protected from future similar events.

To view an updated Cause Map of the event, including the CSB’s interim recommendations, click “Download PDF” above. Click here to view information on the CSB’s ongoing investigation.

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Runway Fire Forces Evacuation of Airplane

By ThinkReliability Staff

On September 8, 2015, an airplane caught fire during take-off from an airport in Las Vegas, Nevada. The pilot was able to stop the plane, reportedly in just 9 seconds after becoming aware of the fire. The crew then evacuated the 157 passengers, 27 of whom received minor injuries as a result of the evacuation by slide. Although the National Transportation Safety Board (NTSB) investigation is ongoing, information that is known, as well as potential causes that are under consideration, can be diagrammed in a Cause Map, or visual root cause analysis.

The first step of Cause Mapping is to define the problem by completing a problem outline. The problem outline captures the background information (what, when and where) of the problem, as well as the impact to the goals. In this case, the safety goal is impacted due to the passenger injuries. The evacuation of the airplane impacts the customer service goal. The NTSB investigation impacts the regulatory goal. The schedule goal is impacted by a temporary delay of flights in the area, and the property goal is impacted by the significant damage to the plane. The rescue, response and investigation is an impact to the labor goal.

The Cause Map is built by beginning with one of the impacted goals and asking “Why” questions to develop the cause-and-effect relationships that led to an issue.   In this case, the injuries were due to evacuation by slide (primarily abrasions, though some sources also said there were some injuries from smoke inhalation). These injuries were caused by the evacuation of the airplane. The airplane was evacuated due to an extensive fire. Another cause leading to the evacuation was that take-off was aborted.

The fact that take-off was able to be aborted, for which the pilot has been hailed as a hero, is actually a positive cause. Had the take-off been unable to be aborted, the result would likely have been far worse. In the case of the Concorde accident, a piece of debris on the runway ruptured a tire, which caused damage to the fuel tank, leading to a fire after the point where take-off could be aborted. Instead, the aircraft stalled and crashed into a hotel, killing all onboard the craft and 4 in the hotel. The pilot’s ability to quickly save the plane almost certainly saved many lives.

The fire is thought to have been initiated by an explosion in the left engine due a catastrophic uncontained explosion of the high-pressure compressor. This assessment is based on the compressor fragments that were found on the runway. This likely resulted from either a bird strike (as happened in the case of US Airways flight 1549), or a strike from other debris on the runway (as occurred with the Concorde), or fatigue failure of the engine components due to age. This is the first uncontained failure of this type of engine, so some consider fatigue failure to be less likely. (Reports of an airworthiness directive after cracks were detected in weld joints of compressors were in engines with different parts and a different compressor configuration.)

In this incident, the fire was unable to be put out without assistance from responding firefighters. This is potentially due to an ongoing leak of fuel if fuel lines were ruptured and the failure of the airplane’s fire suppression system, which reportedly deployed but did not extinguish the fire. Both the fuel lines and fire suppression system were likely damaged when the engine exploded. The engine’s outer casing is not strong enough to contain an engine explosion by design, based on the weight and cost of providing that strength.

The NTSB investigation is examining airplane parts and the flight data and cockpit voice recorders in order to provide a full accounting of what happened in the incident. Once these results are known, it will be determined whether this is considered an anomaly or whether changes to all planes using a similar design and configuration need to take action to prevent against a similar event recurring.

To view the initial investigation information on a one-page downloadable PDF, please click “Download PDF” above.

 

Root Cause Analysis - Incident Investigation

Waste Released from Gold King Mine

By Renata Martinez

On August 5, 2015 over 3 million gallons of waste was released from Gold King Mine into Cement Creek which then flowed into the Animas River. The orangish colored plume moved over 100 miles downstream from Silverton, Colorado through Durango reaching the San Juan River in New Mexico and eventually making its way to Lake Powell in Utah (although the EPA stated that the leading edge of the plume was no longer visible by the time it reached Lake Powell a week after the release occurred).

Some of the impacts were immediate.  No workers at the mine site were hurt in the incident but the collapse of the mine opening and release of water can be considered a near miss because there was potential for injuries. After the release, there were also potential health risks associated with the waste itself since it contained heavy metals.

Water sources along the river were impacted and there’s potential that local wells could be contaminated with the waste.   To mitigate the impacts, irrigation ditches that fed crops and livestock were shut down.  Additionally, the short-term impacts include closure of the Animas River for recreation (impacting tourism in Southwest Colorado) from August 5-14.

The long-term environmental impacts will be evaluated over time, but it appears that the waste may damage ecosystems in and along the plume’s path. There are ongoing investigations to assess the impact to wildlife and aquatic organisms, but so far the health effects from skin contact or incidental ingestion of contaminated river water are not considered significant.

“Based on the data we have seen so far, EPA and the Agency for Toxic Substances and Disease Registry (ATSDR) do not anticipate adverse health effects from exposure to the metals detected in the river water samples from skin contact or incidental (unintentional) ingestion. Similarly, the risk of adverse effects to livestock that may have been exposed to metals detected in river water samples from ingestion or skin contact is low. We continue to evaluate water quality at locations impacted by the release.”

The release occurred when the EPA was working to stabilize the existing adit (a horizontal shaft into a mine which is used for access or drainage). The force of the weight of a pool of waste in the mine overcame the strength of the adit, releasing the water into the environment.  The  EPA’s scope of work at Gold King Mine also included assessing the ongoing leaks from the mine to determine if the discharge could be diverted to retention ponds at the Red and Bonita sites.

The wastewater had been building up since the adit collapsed in 1995.  There are networks and tunnels that allow water to easily flow between the estimated 22,000 mine sites in Colorado.  As water flows through the sites it reacts with pyrite and oxygen to form sulfuric acid.  When the water is not treated and it contacts (naturally occurring) minerals such as zinc, lead, cadmium, copper and aluminum and breaks down the heavy metals, leaving tailings.  The mines involved in this incident were known to have been leaking waste for years.  In the 90s, the EPA agreed to postpone adding the site to the Superfund National Priorities List (NPL), so long as progress was made to improve the water quality of the Animas River.  Water quality improved until about 2005 at which point it was re-assessed.  Again in 2008, the EPA postponed efforts to include this area on the NPL.  From the available information, it’s unclear if this area and the waste pool would have been treated if the site was on the NPL.

In response, the “EPA is working closely with first responders and local and state officials to ensure the safety of citizens to water contaminated by the spill. ” Additionally, retention ponds have been built below the mine site to treat the water and continued sampling is taking place to monitor the water.

So how do we prevent this from happening again?  Mitigation efforts to prevent the release were unsuccessful.  This may have been because the amount of water contained in the mine was underestimated.  Alternatively, if the amount of water in the mine was anticipated (and the risk more obvious) perhaps the excavation work could have been planned differently to mitigate the collapse of the tunnel.  As a local resident, I’m especially curious to learn more facts about the specific incident (how and why it occurred) and how we are going to prevent this from recurring.

The EPA has additional information available (photos, sampling data, historic mine information) for reference: http://www2.epa.gov/goldkingmine

Root Cause Analysis - Incident Investigation

Explosions raise concern over hazardous material storage

By ThinkReliability Staff

On August 12, a fire began at a storage warehouse in Tianjin, China. More than a thousand firefighters were sent in to fight the fire. About an hour after the firefighters went in, two huge explosions registered on the earthquake measurement scale (2.3 and 2.9, respectively). Follow-on explosions continued and at least 114 firefighters, workers and area residents have been reported dead so far, with 57 still missing (at this point, most are presumed dead).

Little is known for sure about what caused the initial fire and continuing explosions. What is known is that the fire, explosions and release of hazardous chemicals that were stored on site have caused significant impacts to the surrounding population and rescuers. These impacts can be used to develop cause-and-effect relationships to determine the causes that contributed to an event. It’s particularly important in an issue like this – where so many were adversely affected – to find effective solutions to reduce the risk of a similar incident recurring in the future.

Even with so much information unavailable, an initial root cause analysis can identify many issues that led to an adverse event. In this case, the cause of the initial fire is still unknown, but the site was licensed to handle calcium carbide, which releases flammable gases when exposed to water. If the chemical was present on site, the fire would have continued to spread when firefighters attempted to fight it using water. Contract firefighters, who are described as being young and inexperienced, have said that they weren’t adequately trained for the hazards they faced. Once the fire started, it likely ignited explosive chemicals, including the 800 tons of ammonium nitrate and 500 tons of potassium nitrate stored on site.

Damage to the site released those and other hazardous chemicals. More than 700 tons of sodium cyanide were reported to be stored at the site, though it was only permitted 10 tons at a time. Sodium cyanide is a particular problem for human safety. Says David Leggett, a chemical risk consultant, “Sodium cyanide is a very toxic chemical. It would take about a quarter of teaspoon to kill you. Another problem with sodium cyanide is that it can change into prussic acid, which is even more deadly.”

But cleaning up the mess is necessary, especially because there are residents living within 2,000 ft. of the site, despite regulations that hazardous sites are a minimum of 3,200 ft. away from residential areas. Developers who built an apartment building within the exclusion zone say they were told the site stored only common goods. Rain could make the situation worse, both by spreading the chemicals and because of the potential that the released chemicals will react with water.

The military has taken over the response and cleanup. Major General Shi Luze, chief of the general staff of the military region, said, “After on-site inspection, we have found several hundred tons of cyanide material at two locations. If the blasts have ripped the barrels open, we neutralize it with hydrogen peroxide or other even better methods. If a large quantity is already mixed with other debris, which may be dangerous, we have built 1-meter-high walls around it to contain the material — in case of chemical reactions if it rains. If we find barrels that remain intact, we collect them and have police transport them to the owners.”

In addition to sending in a team of hazardous materials experts to neutralize and/or contain the chemicals and limiting the public from the area in hopes to limit further impact to public safety, the state media had said they were trying to prevent rain from falling, presumably using the same strategies developed to ensure clear skies for the 2008 Summer Olympics. Whether it worked or not hasn’t been said, but it did rain on August 18, nearly a week after the blast, leaving white foam that residents have said creates a burning or itchy sensation with contact.

View an initial Cause Map of the incident by clicking on “Download PDF” above.

Root Cause Analysis - Incident Investigation

Unintended Consequences, Serendipity, and Prawns

By ThinkReliability Staff

The Diama dam in Senegal was installed to create a freshwater reservoir. Unfortunately, that very dam also led to an outbreak of schistosomiasis. This was an unintended consequence: a negative result from something meant to be positive.   Schistosomiasis, which weakens the immune system and impairs the operation of organs, is transmitted by parasitic flatworms. These parasitic flatworms are hosted by snails. When the dam was installed, the snails’ main predators lost a migration route and died off. Keeping the saltwater out of the river allowed algae and plants that feed the snails to flourish. The five why analysis of the issue would go something like this: The safety goal is impacted. Why? Because of an outbreak of schistosomiasis. Why? Because of the increase in flatworms. Why? Because of the increase in snails. Why? Because of the lack of snail predators. Why? Because of the installation of the dam.

Clearly, there’s more to it. We can capture more details about this issue in a Cause Map, or visual form of root cause analysis. First, it’s important to capture the impact to the goals. In this case, the safety goal is impacted because of a serious risk to health and the environmental goal is impacted due to the spread of parasitic flatworms. The customer service goal (if we consider customers as all those who get water from the reservoir created by the dam) is impacted due to the outbreak of schistosomiasis.

Beginning with the safety goal, we can ask why questions. Instead of including just one effect, we include all effects to create a map of the cause-and-effect relationships. The serious risk to health is caused by the villagers suffering from schistosomiasis, which can cause serious health impacts. The villagers are infected with schistosomiasis and do not receive effective treatment. Not all those infected are receiving drugs due to cost and availability concerns. The drugs do not reverse the damage already done. And, most importantly, even those treated are quickly reinfected as they have little choice but to continue to use the contaminated water.

The outbreak of schistosomiasis is caused by the spread of parasitic flatworms, which carry the disease. The increase in flatworms is caused by the increased population of snails, which host the flatworms. The snail population increased after the installation of the dam killed off their predators and increased their food supply.

Many solutions to this issue were attempted and found to be less than desirable. Administering medication for treatment on its own wasn’t very effective, because (as described above) the villagers kept getting reinfected. The use of molluscicide killed off other animals in the reservoir as well. Introducing crayfish to eat the snails was derided by environmentalists as they were considered an invasive species. But they were on the right track. Now, a team is studying the reintroduction of the prawns which ate the snails. During the pilot study, the rates of schistosomiasis decreased. In addition, the prawns will serve as a valuable food source. This win-win solution is an example of serendipity and should actually return money to the community. Says Michael Hsieh, the project’s principal investigator and an assistant professor of urology, “The broad potential of this project is validation of a sustainable economic solution that not only addresses a major neglected tropical disease, but also holds the promise of breaking the poverty cycle in affected communities.”

Introducing animals to get rid of other animals can be problematic, as Macquarie Island discovered when they introduced cats to eat their exploding rodent population who ate the native seabirds). (Click here to read more about Macquarie Island.) Further research is planned to ensure the project will continue to be a success. To learn more about the project, click here. Or, click “Download PDF” to view an overview of the Cause Map.