All posts by Kim Smiley

Mechanical engineer, consultant and blogger for ThinkReliability, obsessive reader and big believer in lifelong learning
Root Cause Analysis - Incident Investigation

Small fire leads to thousands of canceled flights

By Kim Smiley

Starting August 8, 2016, thousands of travelers were stranded worldwide after widespread cancelations and delays of Delta Air Lines flights. The disruptions continued over several days and the impacts lingered even longer.  The flight issues made headlines around the globe and the financial impact to the company was significant.

So what happened? What caused this massive headache to so many travelers? The short answer is a small fire in an airline data center, but a much longer answer is needed to understand what caused this incident. A Cause Map, a visual format for performing a root cause analysis, can be used to analyze this issue. All of the causes that contributed to an issue are visually laid out to intuitively show cause-and-effect relationships in a Cause Map.  The Cause Map is built by asking “why” questions and adding the answers.  For an effect with more than one cause, all of the causes that contributed to the effect are listed vertically and separated by an “and”.  (Click on “Download PDF” to see an intermediate level Cause Map of this incident.)

So why were so many flights canceled and delayed? There was a system-wide computer outage and the airline depends on computer systems for everything from processing check-ins to assigning crews and gates.  Bottom line, no flights leave on time without working computer systems.  The issues originated at a single data center, but the design of the system led to cascading computer issues that impacted systems worldwide.  The airline has not released any specific details about why exactly the issue spread, but this is certainly an area investigators would want to understand in order to create a solution to prevent a similar cascading failure in the future.

In a statement, the company indicated that an electrical component failed, causing a small fire at the data center. (Again, the specifics about what type of component and what caused the failure haven’t been released.) The fire caused a transformer to shut down which resulted in a loss of primary power to the data center.  A secondary power system did kick on, but not all servers were connected to backup power.  No details have been released about why some servers were not powered by the secondary power supply.

Compounding the frustration for the impacted travelers is the fact that they were unable to get updated flight information. Flight status systems, including airport monitors, continued to show that all flights were on time during the period of the cancelations and delays.

Once a large number of flights are disrupted, it is difficult to return to a normal flight schedule.  The rotation schedule for airlines and pilots has to be redone, which can be time-consuming.  Many commercial flights operate near capacity so it can be difficult to find seats for all the passengers impacted by canceled and delayed flights.  Delta has tried to compensate travelers impacted by this incident by offering refunds and $200 in travel vouchers to people whose flights were canceled or delayed at least three hours, but an incident of this magnitude will naturally impact customer confidence in the company.

This incident is a good reminder of the importance of building robust systems with functional backups; otherwise a small problem can spread and quickly become a big problem.

Root Cause Analysis - Incident Investigation

911 Outage in Baltimore

By Kim Smiley

Nobody ever wants to find themselves in the position of dialing 911.  But imagine how quickly a bad situation could get even worse if nobody answered your call for emergency help.  That is exactly what happened on July 16, 2016 to people in Baltimore, Maryland.  For about two hours, people dialing 911 in Baltimore got a busy signal.

This incident can be investigated by building a Cause Map, a visual root cause analysis.  A Cause Map intuitively lays out the many causes that contributed to an issue to show all the cause-and-effect relationships.  By focusing on the multiple causes, rather than a single root cause analysis, the range of solutions considered is naturally widened.

The first step in the Cause Mapping process is to fill in an Outline with the basic background information for the incident.  Additionally, the Outline is used to capture how the incident impacts the overall goals.  This incident, like most incidents, impacted more than one goal.  For example, the safety goal is impacted because of the delay in emergency help and the customer service goal is impacted because people were unable to reach 911 operators.

The bottom line on the Outline is used to note the frequency of similar incidents.  This is important because an incident that has occurred 12 times before may warrant a different level of investigation than an isolated incident.  For this example, newspapers reported a previous 911 outage in June in the Baltimore area. The outages appear to have been caused by different issues, but do raise questions about the overall stability of the 911 system in Baltimore. Investigators should determine if the multiple outages are related and indicative of bigger issues than just this one incident.

Once the Outline is completed, the Cause Map itself is built by asking “why” questions.  So why was there a 911 outage for about 2 hours? Newspapers have reported that the outage occurred because of electrical power failures after both the main and back-up power systems shut down.  The power systems shut down because of a malfunctioning air conditioning unit.  No details have been released about exactly why the air conditioning units malfunctioned, but additional information could quickly be added to the Cause Map as it becomes known.

The final step in the Cause Mapping process is to develop and implement solutions to reduce the risk of the problem reoccurring. The investigation into this incident is still ongoing and no information about potential long-term solutions has been announced. In the short term, callers were asked to dial 311 or call their closest fire station or police district station if they heard a busy signal or were otherwise unable to get through to 911.  It is probably not a bad idea for all of us to have the numbers of our local fire and police stations on hand, just in case.

Root Cause Analysis - Incident Investigation

FAA Proposes Amazon Fine for Hazardous Shipment

By Kim Smiley

The Federal Aviation Administration (FAA) recently proposed fining Amazon $350,000 for shipping a product that allegedly violated hazardous materials regulations. The package in question was shipped by Amazon from Louisville, Kentucky, to Boulder, Colorado and contained a one-gallon container of corrosive drain cleaner with the colorful name Amazing! LIQUID FIRE. During transit, the package leaked and 9 UPS workers were exposed to the drain cleaner and reported a burning sensation. The workers were treated with a chemical wash and experienced no further issues, but this incident highlights issues with improper shipment of hazardous materials.

A Cause Map, a visual root cause analysis, can be built to analyze this issue by visually laying out the cause-and-effect relationships that contributed to the issue.  The first step in the Cause Mapping method is to fill in an Outline.  The top part of the Outline lists the basic background information for the issue, such as the date and time.  The bottom portion of the Outline has a section to list how the problem impacts the overall goals of the organization.  Most problems have more than one impact and this incident is no exception.  For example, the safety goal is impacted because workers were exposed to hazardous chemicals and the regulatory goal is impacted because of the FAA investigation and the proposed fine.

The frequency of the issue is listed on the last line of the Outline.  Identifying the frequency is important because an issue that has occurred a dozen times may likely warrant a more detailed investigation than an issue that has been reported only once.  For this example, Amazon has had at least 24 hazardous materials violations between February 2013 and September 2015 so the concerns about improperly handling hazardous materials goes beyond the issues with this one package.

Once the Outline is completed, the Cause Map is built by starting at one of the impacted goals and asking “why” questions. Starting at the safety goal for this example, the first question would be “why were workers exposed to hazardous chemicals?”. This happened because the workers were handling a package containing hazardous chemicals, a package containing hazardous chemicals leaked, and inadequate precautions were taken to prevent the workers being exposed to the chemicals. When there is more than one cause that contributes to an effect, the causes are listed vertically and separated by an “and”.

To continue building the Cause Map, ask “why” questions for each of the causes already listed. The workers were handling the package because it shipped by air via UPS. Inadequate precautions were taken to prevent exposure to the chemical because workers were unaware that package contained hazardous chemicals. Chemicals leaked because they were not properly packaged.  Why questions should continue to be asked until no more information is known or no useful detail can be added to the Cause Map. To view an intermediate level Cause Map of this issue with more information, click on “Download PDF” above.

The final step in the Cause Mapping process is to use the Cause Map to develop and implement solutions to reduce the risk of the problem reoccurring. More information about what exactly led to improperly packaged and labeled hazardous materials being shipped would be needed to develop useful solutions in this example, but hopefully a fine of this size and the negative publicity it generated will help spark efforts to make improvements.

Uncategorized

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.

Uncategorized

Florida under attack by another invasive species

By Kim Smiley

Florida’s warm climate has made it an appealing home to many invasive species, such as Burmese pythons (see our previous blog) and giant African land snails.  Researchers fear another species, the Nile monitor lizard,  is also threatening native wildlife.  Nile monitor lizards are intimidating reptiles, growing up to 5 feet long, and they are not fussy about what they eat, consuming almost anything smaller than they are.  They will feed on mammals, birds, reptiles, amphibians, fish and eggs. There have even been reports of Nile monitor lizards making a meal out of pet cats.

This issue can be analyzed by building a Cause Map, a visual format for performing a root cause analysis.  A Cause Map visually lays out the cause-and-effect relationships that contribute to an issue so that they are easily understood.  The first step in building a Cause Map is to fill in an Outline to help define the problem.  Basic background information is recorded in the Outline in addition to how the problem impacts the overall goals.  To build a Cause Map, start at one of the impacted goals, start asking “why” questions and add the answers to the Cause Map. For this example, we will focus on the environmental goal.

Invasive Nile monitor lizards impact the environmental goal because they can have a negative impact on native wildlife.  Why? Monitor lizards eat a varied diet and there are permanent breeding populations of these lizards in Florida.  Why are there populations of Nile monitor lizards in Florida? They were introduced into the environment and the number of Nile monitor lizards in the wild quickly increased. (It’s a bit awkward to write out the “why” questions in this way, but click on “Download PDF” above to see how the Cause Map would visually lay out for this example.)

Nile monitor lizards are basically a perfect (or perfectly bad, depending on your point of view) invasive species.  They grow quickly and breed at an early age.  They lay many eggs at once, as many as 60 eggs in a single clutch. Their natural habitat is very similar to southern Florida and they have a tendency to wander over long distances so it isn’t surprising that they would quickly spread from where they were originally introduced into the wild.

Researchers don’t know exactly how Nile monitor lizards were first introduced into the wild, but it typically occurs when pets escape or are released.  Nile monitor lizards are sold as pets.  Often they are small when sold, but they quickly grow large and can be aggressive.  Owners may release their pets into the wild if they become tired of them or are unable to continue caring for the lizards.  It’s easy to see how a small pet lizard may seem like a good idea, but turn out to be a less than ideal roommate when they have grown into a large, active predatory adult lizard, complete with sharp claws and teeth.  Not to mention, the cost of feeding such a pet might be more than anticipated.

Researchers are still working on developing the best methods to control Nile monitor lizard populations in Florida.  (It is unlikely that Nile monitor lizards will ever be eradicated from Florida, but officials hope to control the numbers.)  Three permanent breeding populations of Nile monitor lizards have been identified, one of which is estimated to be hold over 1,000 lizards.

DNA testing has shown that there are actually two distinct species of Nile monitor lizards and all lizards tested in Florida have been determined to be the newly-named West African Nile monitor lizards. West African Nile monitor lizards aren’t likely to spread too far north in Florida and beyond because they aren’t adapted to cold weather.  The other species of Nile monitor lizards is native to a cooler part of Africa and could potentially spread to a wider area if ever introduced into the wild in the United States.

Bottom line: please don’t release any nonnative species anywhere (even goldfish – see our previous blog).  You may think you are doing the right thing for your pet, but invasive species can do massive damage to native wildlife.  Call a pet store or your local fish and wildlife service if you can no longer care for a pet.  You can also help by reporting sightings of nonnative species to your local fish and wildlife services.

Uncategorized

Oil Leaked from shipwreck near Newfoundland

By Kim Smiley

On March 31, 2013, oil was reported in Notre Dame Bay, Newfoundland.  Officials traced the source of the oil back to a ship, the Manolis L, that sank in 1985 after running aground.  The Manolis L is estimated to have contained up to 462 tons of fuel and 60 tons of diesel when it sank and much of that oil is believed to still be contained within the vessel.  Officials are working to ensure the oil remains contained, but residents of nearby communities who rely on tourism and fishing are concerned about the potential for more oil to be released into the environment.

A Cause Map, a visual format for performing root cause analysis, can be built to better understand this issue.  There are three steps in the Cause Mapping process. The first step is to fill out an Outline with the basic background information along with listing how the problem impacts the goals.  There is also space on the Outline to note the frequency of the issue.  For this example, 2013 was the first time oil was reported to be leaking from this particular sunken ship, but there have been 700 at-risk sunken vessels identified in Canadian waters alone.  It’s worth noting this fact because the amount of resources a group is willing to use to address a problem may well depend on how often it is expected to occur.  One leaking sunken ship is a different problem than potentially having hundreds that may require action.

The second step is to perform the analysis by building the Cause Map.  A Cause Map is built by asking “why” questions and laying out the answers to visually show the cause-and-effect relationships.  Once the causes have been identified, the final step is to develop and implement solutions to reduce the risk of similar problems occurring in the future.  Click on “Download PDF” to view an Outline and intermediate level Cause Map for this problem.

In this case, the environmental goal is clearly impacted because oil was released into the environment.  Why? Oil leaked out of a sunken ship because a ship had sunk that contained a large quantity of oil and there were cracks in the hull.  The hull of this particular ship is thin by modern standards (only a half-inch) and it has been sitting in sea water for the last 30 years.  A large storm hit the region right before oil was first reported and it is believed that the hull (already potentially weakened by corrosion) was damaged during the storm.  The Coast Guard identified two large cracks in the ship that were leaking oil during their investigation.

Once the causes of the issue have been identified, the final step is to implement solutions to reduce the risk of future problem.  This is where a lot of investigations get tricky.  It is often easier to identify the problem than to actually solve it. It can be difficult to determine what level of risk is acceptable and how many resources should be allotted to an issue.  The cracks in the hull of the Manolis L have been patched using weighted neoprene sealants and a cofferdam has been installed to catch any oil that leaks out.  The vessel is being monitored by the Canadian Coast Guard via regular site visits and aerial surveillance flights. But the oil remains in the vessel so there is the potential that it could be released into the environment.

Many local residents are fighting for the oil to be removed from the sunken ship, rather than just contained, to further reduce the risk of oil being released into the environment. But removing oil from a sunken ship is very expensive.  In 2013, it cost the Canadian Coast Guard about $50 million to remove oil from a sunken ship off the coast of British Columbia. So far, officials feel that the measures in place are adequate and that the risk doesn’t justify the cost of removing the oil from the vessel. If they are right, the oil will stay safely contained at a fraction of the cost of removing it, but if they are wrong there could be lasting damage to local communities and wildlife.

In situations like this, there are no easy answers.  Anybody who works to reduce risk faces similar tradeoffs and generally the best you can do is to understand a problem as thoroughly as possible to make an informed decision about the best use of resources.

Root Cause Analysis - Incident Investigation

Worker dies while manually measuring tank

By Kim Smiley

The potential danger of confined spaces is well documented, but nine fatalities have shown that people working near open hydrocarbon storage hatches can also be exposed to dangerous levels of hydrocarbon gases and oxygen-deficient atmospheres.  NPR recently highlighted this issue in an article entitled “Mysterious Death Reveals Risk In Federal Oil Field Rules” that discussed the death of Dustin Bergsing.  His job duties included opening the hatch on a crude oil storage tank to measure the level of the oil and was found dead next to an open hatch.  He was healthy and only 21 years old.

A Cause Map, a visual format for performing a root cause analysis, can be used to help explain what happened to cause his death.  A Cause Map intuitively lays out the cause-and-effect relationships that contributed to an issue and is built by asking “why” questions.  Click on “Download PDF” to view a high level Cause Map of this accident.

So why did his death occur?  An autopsy showed that his death occurred because he had hydrocarbons in his blood.  This occurred because he was exposed to hydrocarbon vapor and he remained in the dangerous environment. (When two causes both contribute to an effect, they are listed vertically on the Cause Map and separated by an “and”.)

When a person is exposed to hydrocarbon vapor, they get disoriented before passing out so it is very difficult for them to get to safety on their own.  Bergsing was working alone at the time of his death and no one was aware that he was in trouble before it was too late.

He was exposed to hydrocarbon gases because he opened a hatch on a crude oil storage tank and the gas had collected at the top of the tank.  He opened the hatch because he planned to manually measure the tank level by dropping a rope inside. Manual tank measurement is a common method to determine level in crude oil storage tanks. Crude oil contains volatile hydrocarbons that can bubble out of the crude oil and collect at the top; the gas will rush out of the tank if a hatch is opened.

Additionally, he wasn’t wearing adequate PPE equipment because it wasn’t required by any regulations and there was limited awareness of this danger.

After his and the other deaths, the industry is starting to become more aware of this issue.  The National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA) issued a hazard alert bulletin that identified health and safety risks to workers who manually gauge or sample fluids on production and flowback tanks from exposure to hydrocarbon gases and vapors and exposure to oxygen-deficient atmospheres. In addition to working to raise awareness of the issue, OSHA and NIOSH made recommendations to improve working safety that include the following:

– Implementing alternate procedures that allow workers to monitor tank levels and sample without opening hatches

– Installing hatch pressure indicators

– Conducting worker exposure assessments

– Providing training on the hazard and posting hazard signage

– Not permitting employees to work alone

Please read the OSHA and NIOSH hazard alert bulletin for more information and a full list of the recommendations. Many of the recommendations would be expensive and time-consuming to implement, but some may be relatively simple ways to reduce risk. Continuing to provide information to workers about the potential hazards might be a good first step to improve their safety.

Root Cause Analysis - Incident Investigation

DC Metro shut down for entire day after fire for inspections

By Kim Smiley 

A fire in a DC Metro tunnel early on March 14, 2016 caused delays on three subway lines and significant disruption to both the morning and evening commutes.  There were no injuries, but the similarities between this incident and the deadly smoke incident on January 12, 2015 (see our previous blog on this incident) led officials to order a 24-hour shutdown of the entire Metro system for inspections and repairs.

The investigation into the Metro fire is still ongoing, but the information that is known can be used to build an initial Cause Map.  A Cause Map is built by asking “why” questions and visually laying out all the causes that contributed to an incident.  Cause Mapping an issue can identify areas where it may be useful to dig into more detail to fully understand a problem and can help develop effective solutions.

So why was there a fire in the Metro tunnel?  Investigators have not released details about the exact cause, but have stated that the fire was caused by issues with a jumper cable.  Jumper cables are used in the Metro system to bridge gaps in the third rail, essentially functioning as extension cords.  The Metro system uses gaps in the third rail to create safer entry and exit spaces for both workers and passengers because of the potential danger of contact with the electrified third rail.  The third rail carries 750 volts of electricity used to power Metro trains and could cause serious injury or even death if accidently touched.

The jumper cables also carry high voltage and fires and/or smoke can occur if one malfunctions.  Investigators have not confirmed the exact issue that lead to this fire, but insulation failures have been identified in other locations and is a possible cause of the fire. (Possible causes can be added to the Cause Map with a “?” to indicate that more evidence is needed.)

One of the things that is always important to consider when investigating an incident is the frequency of occurrence of similar issues.  The scope of the investigation and possible solutions considered will likely be different if it was the 20th time an incident has occurred rather than the first. In this case, the fire was similar to another incident in January 2015 that caused a passenger death.  Having a second incident occur so soon after the first naturally raised questions about whether there were more unidentified issues with jumper cables.  The Metro system uses approximately 600 jumper cables and all were inspected during the day-long shutdown. Twenty-six issues were identified and repaired. Three locations had damage severe enough that Metro would have immediately stopped running trains through them if the extent of the damage had been known.

The General Manger of the DC Metro system, Paul J. Wiedefeld, is relatively new to his position and has been both praised and criticized for the shutdown.  Trying to implement solutions and reduce risk is always a balancing act between costs and benefits.  Was the cost of a full-day shutdown and inspections of all jumper cables worth the benefit of knowing that the cable jumpers have all been inspected and repaired?  At the end of the day, it’s a judgement call, but I personally would be more comfortable riding the Metro with my children now.

Root Cause Analysis - Incident Investigation

For the first time, autonomous car is at fault for a crash

By Kim Smiley

On February 14, 2016, the self-driving Google car was involved in a fender bender with a bus in Mountain View, California.  Both vehicles were moving slowly at the time and the accident resulted in only minor damage and no injuries.  While this accident may not seem like a very big deal, the collision is making headlines because it is the first time one of Google’s self-driving cars has contributed to an accident.  Google’s self-driving cars have been involved in 17 other fender benders, but each of the previous accidents was attributed to the actions of a person, either the drivers of other vehicles or the Google test driver (while they were controlling the Google car).

The accident in question occurred after the Google car found itself in a tricky driving situation while attempting to merge.  The Google car had moved over to the right lane in anticipation of making a right turn.  Sandbags had been stacked around a storm drain, blocking part of the right lane.  The Google car stopped and waited for the lane next to it to clear so that it could drive around the obstacle.  As the Google car moved into the next lane it bumped a bus that was coming up from behind it.  Both the driver of the bus and the Google car assumed that the other vehicle would yield.  The test driver in the Google car did not take control of the vehicle and prevent the car from moving into the lane because he also assumed the bus would slow down and allow the car to merge into traffic. (Click on “Download PDF” to view a Cause Map that visually lays out the causes that contributed to this accident.)

Thankfully, this collision was a relatively minor accident. No one was hurt and there was only relatively minor damage to the vehicles involved. Lessons learned from this accident are already being incorporated to help prevent a similar incident in the future. Google has stated that the software that controls the self-driving cars has been tweaked so that the cars will recognize that buses and other large vehicles may be less likely to yield than other types of vehicles. (I wonder if there is a special taxi tweak in the code?)

It’s also worth noting that one of the driving factors behind the development of autonomous cars is the desire to improve traffic safety and reduce the 1.2 million traffic deaths that occur every year.  The Google car may have contributed to this accident, but Google cars have so far generally proved to be very safe.  Since 2009, Google cars have driven more than 2 million miles and have been involved in fewer than 20 accidents.

One of the more interesting facets of this accident is that it raises hard questions about liability.  Who is responsible when a self-driving car causes a crash? The National Highway Traffic Safety Administration (NHTSA) recently determined that for regulatory purposes, autonomous vehicle software is a “driver” which may mean that auto manufacturers will assume greater legal responsibility for crashes.  NHTSA is working to develop guidance for self-driving vehicles, which they plan to release by July, but nobody really knows yet the impact self-driving cars will have on liability laws and insurance policies.  In addition to the technology issues, there are many legal and policy questions that will need to be answered before self-driving cars can become mainstream technology.

Personally, I am just hoping this technology is commercially available before I reach the age where my kids take away my car keys.

Root Cause Analysis - Incident Investigation

Heavy metal detected in moss in Portland

By Kim Smiley

Residents and officials are struggling to find a path forward after toxic heavy metals were unexpectedly found in samples of moss in Portland, Oregon. According to the U.S. Forest Service, the moss was sampled as part of an exploratory study to measure air pollution in Portland.  The objective of the study was to determine if moss could be used as a “bio-indicator” of hydrocarbons and heavy metals in air in an urban environment.  Researchers were caught off guard when the samples showed hot spots of relatively high heavy metal levels, including chromium, arsenic, and cadmium (which can cause cancer and kidney malfunction).  Portland officials and residents are working to determine the full extent of the problem and how it should be addressed.

So where did the heavy metals come from?  And how is it that officials weren’t already aware of the potential issue of heavy metals in the environment? The investigation into this issue is still ongoing, but an initial Cause Map can be built to document what is known at this time.  A Cause Map is built by asking “why” questions and visually laying out all the causes that contributed to the problem.  (Click on “Download the PDF” to view the initial Cause Map.)

Officials are still working to verify where the heavy metals are coming from, but early speculation is that nearby stained-glass manufacturers are the likely source.  Heavy metals are used during the glass manufacturing process to create colors. For example, cadmium is used to make red, yellow and orange glass and chromium is used to make green and blue glass. The hot spots where heavy metals were detected surround two stained-glass manufacturers, but there are other industrial facilities nearby that may have played a role as well.  There are still a lot of unknowns about the actual emissions emitted from the glass factories because no testing has been done up to this point.  Testing was not required by federal regulations because of the relatively small size of the factories.  If the heavy metals did in fact originate from the glass factories, many hard questions about the adequacy of current emissions regulations and testing requirements will need to be answered.

Part of the difficulty of this issue is understanding exactly what the impacts from the potential exposure to heavy metals might be.  Since the levels of heavy metals detected so far are considered below the threshold of “acute”,  investigators are still working to determine what the potential long-term health impacts might be.

A long-term benefit of this mess is the validation that moss can be used as an indicator of urban air quality.  Moss has been used as an “bio-indicator” for air quality since the 1960s in rural environments, but this the first attempt to sample moss to learn about air quality in an urban setting.  As moss is plentiful and testing it is relatively inexpensive, this technique may dramatically improve testing methods used in urban environments.

Both glass companies have voluntarily suspended working with chromium, cadmium and arsenic in response to a request by the Oregon Department of Environmental Quality.  The DEQ has also begun additional air monitoring and begun sampling soil in the impacted areas to determine the scope of the contamination. As officials gain a better understanding of what is causing the issue and what the long-term impacts are, they will be able to develop solutions to reduce the risk of similar problems occurring in the future.