Author Archives: Mark Paradies

UK Rail Accident Investigation Board Investigating a Signal Passed at Danger

Posted: March 27th, 2015 in Accidents, Current Events, Investigations, Pictures

A press release from the UK RAIB:

RAIB is investigating an incident that occurred at 17:25 hrs on Saturday 7 March 2015, in which train reporting number 1Z67, the 16:35 hrs service from Bristol Temple Meads to Southend, passed a signal at danger on the approach to Wootton Bassett junction, Wiltshire. The train subsequently came to a stand across the junction. The signal was being maintained at danger in order to protect the movement of a previous train. However, at the time that the SPAD occurred, this previous train had already passed through the junction and was continuing on its journey. No injuries, damage or derailment occurred as a result of the SPAD.

Wootton Bassett junction is situated between Chippenham and Swindon stations on the Great Western main line and is the point at which the line from Bristol, via Bath, converges with the line from South Wales. It is a double track high speed junction which also features low speed crossovers between the up and down main lines (see figure below for detail).

NewImageWootton Bassett junction in 2012 – the lines shown from left to right are the Up Goods,
Up Badminton, Down Badminton, Up Main and Down Main (image courtesy of Network Rail)

The junction is protected from trains approaching on the up main from Chippenham by signal number SN45, which is equipped with both the Automatic Warning System (AWS) and the Train Protection and Warning System (TPWS). This signal is preceded on the up main by signal SN43, which is also equipped with AWS and TPWS. The maximum permitted line speed for trains approaching the junction from this direction is normally 125 mph. However, on 7 March, a temporary speed restriction (TSR) of 85 mph was in place on the approach to signal SN45. A temporary AWS magnet had been placed on the approach to signal SN43 to warn drivers of this TSR.

Screen Shot 2015 03 27 at 12 28 07 PMA diagram of the layout of Wootton Bassett junction – note that some features have been omitted for clarity (not to scale)

The train which passed signal SN45 at danger consisted of steam locomotive number 34067 ‘Tangmere’, and its tender, coupled to 13 coaches. The locomotive is equipped with AWS and TPWS equipment.
The RAIB’s preliminary examination has shown that, at around 17:24 hrs, train 1Z67 was approaching signal SN43 at 59 mph, when it passed over the temporary AWS magnet associated with the TSR. This created both an audible and visual warning in the locomotive’s cab. However, as the driver did not acknowledge this warning within 2.7 seconds, the AWS system on the locomotive automatically applied the train’s brakes. This brake application should have resulted in the train being brought to a stand. In these circumstances, the railway rule book requires that the driver immediately contact the signaller.

The RAIB has found evidence that the driver of 1Z67 did not bring the train to a stand and contact the signaller after experiencing this brake application. Evidence shows that the driver and fireman instead took an action which cancelled the effect of the AWS braking demand after a short period and a reduction in train speed of only around 8 mph. The action taken also had the effect of making subsequent AWS or TPWS brake demands ineffective.
Shortly after passing the AWS magnet for the TSR, the train passed signal SN43, which was at caution. Although the AWS warning associated with this signal was acknowledged by the driver, the speed of the train was not then reduced appropriately on the approach to the next signal, SN45, which was at danger. Because of the earlier actions of the driver and fireman, the TPWS equipment associated with signal SN45 was unable to control the speed of the train on approach to this signal.

As train 1Z67 approached signal SN45, the driver saw that it was at danger and fully applied the train’s brakes. However, by this point there was insufficient distance remaining to bring the train to a stand before it reached the junction beyond SN45. The train subsequently stopped, standing on both the crossovers and the up and down Badminton lines, at around 17:26 hrs. The signalling system had already set the points at the junction in anticipation of the later movement of 1Z67 across it; this meant that no damage was sustained to either the train or the infrastructure as a result of the SPAD.
The RAIB has found no evidence of any malfunction of the signalling, AWS or TPWS equipment involved in the incident.
The RAIB’s investigation will consider the factors that contributed to signal SN45 being passed at danger, including the position of the temporary AWS magnet associated with the TSR. The investigation will also examine the factors that influenced the actions of the train crew, the adequacy of the safety systems installed on the locomotive and the safety management arrangements. 

RAIB’s investigation is independent of any investigation by the Office of Rail Regulation.

We will publish our findings, including any recommendations to improve safety, at the conclusion of our investigation.

These findings will be available on the our website.

Do Accidents Target a Particular Race?

Posted: March 27th, 2015 in Accidents, Performance Improvement

The Houston Chronicle published an article by Rafael Moure-Eraso of the Chemical Safety Board that was titled: “Hazardous work takes toll on Latinos”.

In the article, Rafael Moure-Eraso claims that Latinos’ “… fatality and injury rates are disproportionately high.” He provides statistics on Latino fatalities and injuries in various industries. He references a report that states the obvious (as many Latinos are recent immigrants, they tend to get lower paying and more dangerous jobs). He also states that latinos are more likely to be at risk as residents near chemical plants (once again, obviously rich people usually don’t site their mansions next to chemical plants and the poor are more likely to buy cheap housing in a less desirable locations – like next door to an industrial site).

The article seems to be a mix of environmental justice political speech and a call for new federal regulations to improve chemical plant safety.

He ends the article with:

You can’t put a price on someone’s life. Latinos help drive the country’s economy working hard for companies big and small, often in dangerous occupations. They have a right to safer workplaces and communities.

That made me think …

  • Are new rights (the right to safety … whatever that is) and new federal programs really the way to improve safety in the workplace? 
  • Do accidents really target specific races? 
  • Would a federally run workplace be safer than those run by commercial companies? 
  • Would safety improve faster with more federal direction?
  • Does the government know better than those in commercial industry how to improve safety?
  • What does management at major companies need to do if they want to avoid a whole new level of “one size fits all” government regulation of process safety and industrial safety?

These are all very interesting questions that take considerable thought. I’d be interested in your opinions. Leave a comment here.

What Pre-Summit Course Should You Attend?

Posted: March 26th, 2015 in Courses, Pictures, Summit, TapRooT

There are 15 potential Pre-Summit Courses to choose from in June and five of the courses are new. That’s probably why so many people are asking which course would be best for them. Therefore, I thought I’d share my thoughts to help people make the best choice.

First, the 15 Courses are:

Next, let me say that I like all these courses. I’ve hand-picked them to be included before the Summit because I think they will help you solve some of your biggest problems. But I understand that you can only attend one of these courses and that you want to pick the best one, so I’ll offer some advice.

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If you haven’t attended a TapRooT® Root Cause Analysis Course before, then you should consider attending the 2-Day TapRooT® Incident Investigation and Root Cause Analysis Course. This is the basic/starter TapRooT® Course that all investigators/root cause analysts should take. It will make the Summit much more valuable if you understand how the TapRooT® Root Cause Analysis System works. And it will help you perform much better investigations of safety, quality, and production issues. This course (like all Pre-Summit Courses) is completely guaranteed. We know that you and your management will agree that you will find root causes that you previously would have missed and develop much more effective corrective actions. 

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Need to improve equipment reliability and apply advanced equipment troubleshooting techniques? Then the Special 2-Day Equifactor® Equipment Troubleshooting and Root Cause Analysis Course is for you. You will learn to apply Heinz Bloch’s advanced troubleshooting techniques to understand how equipment failures occurred. You will then learn to take that information, organize it in a SnapCharT®, identify the Causal Factors, and find each Causal Factors root causes using the TapRooT® Root Cause Tree®. Even equipment troubleshooting experts that have attended this course have commented on the helpfulness of the Heinz Bloch troubleshooting tables and the TapRooT® Root Cause Analysis System. 

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Want to improve your TapRoot® Skills, especially your ability to identify Causal Factors? Then the Advanced Causal Factor Development Course is for you. Ken Turnbull teaches this course using recent examples of accidents, incidents, and near-misses – some straight from the press. You will get lot’s of hands-on exercise practice and instructor feedback.

 

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Do you need to learn to trend your safety and performance data? Especially data from infrequently occurring accident statistics? Would you like to prove that you have improved performance? Or do you need to mathematically demonstrate that a “trend” really isn’t a trend, but rather, is just normal process variation? That’s what the Advanced Trending Techniques Course is all about. I developed after I saw a client’s advanced trending best practices that blew me away. This was trending that really worked and showed when a trend was real and when it was just normal process variation. It was based on advanced lean/six sigma techniques that were specially modified for low frequency accident data. But the same techniques can be applied to all your data. It truly is a one size fits all trending program that will help your management focus their improvement initiative. In the course you will learn how to draw advanced graphs and practice your skills so that you can apply the techniques to your data back home. The course is taught by Kevin McManus, a quality/safety guru, and I know that you will find it enlightening and very useful. 

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The topic of Safety Culture is a hot button in the nuclear, oil, and aviation industry. If you would like to analyze and improve your safety culture, then the TapRooT® Analyzing and Fixing Safety Culture Issues Course is for you. Brian Tink and Brian Tink (Jr & Sr) will show you how to use TapRooT® Tools along with culture analysis tools to analyze and fix safety culture issues. Part of this course is a practice safety culture analysis for your company. If safety culture is a hot button topic at your company, don’t miss this course.

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Interested in risk assessment and management? Want to learn about the latest international standards and how they can help keep your management out of trouble? Then you need to listen to risk management guru Jim Whiting in his course: Risk Assessment and Management Best Practices. Jim shares all the latest risk management techniques and tons of documentation that you will use when you return to work

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Interested in applying advanced root cause analysis techniques in a Lean, Six Sigma, or Quality program? Then attend the TapRooT® Quality/Six Sigma/Lean Advanced Root Cause Analysis Training taught by Chris Vallee. Chris is a Six Sigma Black Belt. He will show you how to use TapRooT® Techniques to analyze and fix quality problems, lean waste issues, and problems discovered using Six Sigma techniques. 

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Do you provide technical support for the TapRooT® Software? Are you a TapRooT® Software “Power Users” who wants to learn the latest tricks and see the latest software updates? Are you interested in the changes coming in Version 6 of the TapRooT® Software. Are you responsible for setting up the TapRoot® Software and preparing the trending fields and linking the software to other databases? Then you want to attend the Getting the Most from Your TapRooT® Software Course taught by Dan VerLinde, VP for Software Development at SI. You will be amazed how much you learn and how much better your software usage will be.

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What is a hazard? Do you see them before they can cause an accident? If you are interested in Hazard recognition and elimination, then the Hazard Recognition Course is for you. Peter Berkholtz, a TapRoot® Instructor from Australia with 25 years of mining and industrial experience, will teach this practical course. Don’t let hazards sneak up on you. Recognize and eliminate them! 

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Did you know you could use the TapRooT® System to solve problems before they cause a crisis? If you want to stop problems BEFORE they happen, then the Proactive Use of TapRooT® Course is for you! Dave Janney developed this course after realizing that people would rather stop fatalities before they happen rather than investigate fatalities after they happen. He explains how TapRooT® can be applied to improve auditing, observations and BBS, and pre-job hazard assessments. Learn new ways to apply the TapRoot® System to proactively improve performance at your facility.

And now for the new courses …

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Interviewing and Investigation Basics: We’ve taught this course before but after we had so many positive comments about Barbara Phillips talk on Body language and interviewing at last year’s TapRooT® Summit, we decided to completely revise the course adding new material on interviewing, I think you will find this course to be engaging, useful, practical, and a good use of your time if you are interested in effective interview techniques and the tools and practices needed to collect information for an effective root cause analysis. 

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Combating Fatigue: fatigue in the workplace (and while driving) is one of the most frequent, and least investigated, causes of accidents. Studies of actual auto accidents that were video tapped inside the car for later analysis showed that actual fatigue and sleeping was often NEVER reported but was the cause of the accident. What can you do to fight fatigue at your company? Get great ideas from fatigue expert Bill Sirois. Learn to understand the risks of fatigue. Learn the five levels of defense against fatigue. Learn to build and improve a Fatigue Risk Management System (required in several industries). Understand specific methods to handle fatigue in high hazard industries. This course has been completely updated since it was last given before the 2012 Summit and we see it as completely new.

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Understanding and Stopping Human Error: Mark Paradies, President of System Improvements and Joel Haight, Professor of Industrial Engineering at the University of Pittsburg, will bring their considerable knowledge of the practical application of human factors engineering to this newly developed course. The course will cover the human abilities and limitations that lead to human error, how to understand error likely situations and error causing designs, and how to apply error reducing techniques that work and to understand why some error reducing techniques that are frequently suggested are of little practical value. If you are interested in human performance and stopping human error (or at least reducing it as far as practical), then don’t miss this course.

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Root Cause Analysis for Sentinel Events & Healthcare Quality Improvement: Ed Skompski, Vice President at System Improvements, has created a 2-Day TapRooT® Course especially for the healthcare community that focuses on the analysis of the root causes of sentinell events and healthcare quality issues. The course is built around real clinical events and uses the TapRooT® System, a recognized good practice in the healthcare industry and that the terminology is recognized by The Joint Commission.

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Creative Corrective Actions: You may remember this course from the past. Michele Lindsay was a TapRooT® Instructor for over a decade. But she now is a performance improvement coach at a healthcare facility. But this year she will be coming back to the TapRooT® Summit and is presenting a new course on creative corrective actions using Dr. Edward de Bono’s Six Thinking Hats™ techniques. 

That’s a lot of training to choose from! But don’t wait too long to register. Seats are limited in these courses and we want you to get your first choice!

Additionally, you get a $200 discount on the training when you also attend the 2015 Global TapRooT® Summit. For more Summit info, see:

http://www.taproot.com/taproot-summit

And if you have any questions about the Pre-Summit Courses or the Summit, please call us at 865-539-2139. Or CLICK HERE to drop us a note with your question. 

 

 

What does a bad day look like?

Posted: March 26th, 2015 in Accidents, Video

Like this if you are a fire fighter…

UK RAIB Investigates Two Separate Rail Incidents

Posted: March 26th, 2015 in Accidents, Current Events, Investigations, Pictures

The UK Rail Accident Investigation Branch announced the start of two rail incident investigations.

The first is an investigation of the injury of a passenger that fell between a London Underground train while being dragged by the train. See the preliminary information at:

http://www.raib.gov.uk/publications/current_investigations_register/150312_Clapham_South.cfm

 This is an accident that was prevented from being worse by the alert actions of the train’s operator.

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The second incident was container blown off a freight train. The preliminary information can be found here:

http://www.raib.gov.uk/publications/current_investigations_register/150307_Scout_Green.cfm

Monday Accident & Lessons Learned: Texas City Refinery Explosion 10 Year Anniversary

Posted: March 24th, 2015 in Accidents, Performance Improvement, Video

Here’s a CSB video …

What do you think? Has PSM improved in the past ten years? What can we learn?

Is “inherently safer designs” the answer?

Are PSM regulations going to stop accidents?

Are government approaches to PSM inadequate?

Are the suggestions of the CSB inadequate?

Leave your comments here.

Process Improvement: Stopping Process Downtime

Posted: March 24th, 2015 in Performance Improvement, Root Cause Analysis Tips

Eliminating waste is at the core of Lean Manufacturing. But even without a lean program, any manufacturing manager knows that process downtime can be costly.

Process downtime can cause:

  • delayed orders, 
  • missed schedules, 
  • missed earning projections, and
  • increased costs, 

Improving process reliability is the same as improving safety, quality, and equipment reliability. When a process reliability problem happens, it needs to be investigated and the root causes need to be found and fixed.

How do you find and fix the causes of process downtime? You can use the same tools that experts use to find the root causes of other  to find the root causes causes of safety incidents, equipment failures, and quality issues. The TapRooT® Root Cause Analysis System.

An example of a process reliability improvement success story is share at:

http://www.taproot.com/archives/18976

And they used TapRooT® to go from losing money to a profitable operation. How did TapRooT® help? Watch the video and read about how to use TapRooT® to find root causes at:

http://www.taproot.com/products-services/about-taproot 

Final Exercise at the 2-Day TapRooT® Incident Investigation and Root Cause Analysis Course in Rome, Italy

Posted: March 19th, 2015 in Courses, Pictures, TapRooT

The students at the Rome 2-Day TapRooT® Incident Investigation and Root Cause Analysis Course show off what they have learned as they analyze an incident from their own company as the final exercise at the course. They then present their work for critique by the rest of the class participants. 

Working on their analysis…

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Presenting …

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If you want to experience the magic of the TaoRooT® Root Cause Analysis System – of how it can help you discover causes that you previously would have missed and develop much more effective corrective actions, then select a course to attend from this upcoming course list:

http://www.taproot.com/store/Courses/

Or have a course at your facility by contacting us at:

 http://www.taproot.com/contact-us

What does a bad day look like?

Posted: March 19th, 2015 in Accidents, Video

Having run an excavator, a track loader, a bulldozer, and a dump truck, this is what your nightmares look like…

2-Day TapRooT® Incident Investigation and Root Cause Analysis Course in Rome, Italy

Posted: March 18th, 2015 in Pictures, TapRooT

Here’s the class in Rome…

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CLICK HERE to view more photos of this great class!

Do you need to learn advanced root cause analysis techniques that work? See the upcoming class schedule at:

http://www.taproot.com/store/Courses/

Monday Accident & Lessons Learned: Crane Accident at Tata Steel Plant in the UK brings £200,000 Guilty Verdict

Posted: March 16th, 2015 in Accidents, Current Events, Investigations, Performance Improvement, Pictures

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Tata Steel was found guilty of violating section 2(1) of the Health and Safety at Work etc. Act 1974. The result? A fine of £200,000 plus court costs of £11,190. 

HSE Inspector Joanne carter said:

Given the potential consequences of a ladle holding 300 tonnes of molten metal spilling its load onto the floor, control measures should be watertight. The incident could have been avoided had the safety measures introduced afterwards been in place at the time.”

The article listed the following corrective action:

“Tata has since installed a new camera system, improved lighting, and managers now scrutinise all pre-use checks. If the camera system fails, spotters are put in place to ensure crane hooks are properly latched onto ladle handles.

Here are my thoughts…

  1. Stating that corrective actions would have prevented an accident is hindsight bias. The question should be, should they have learned these lessons from previous near-misses?
  2. Reviewing the corrective actions, I’m still left with the question … Should the crane be allowed to operate without the camera system working? Are spotters a good temporary fix? How long should a temporary fix be allowed before the operation is shut down?
  3. What allows the latches to fail? Shouldn’t this be fixed as well?

What do you think? Is there more to learn from this accident? Leave your comments here.

Friday Joke: Lost Remote

Posted: March 13th, 2015 in Jokes, Video

Mine in Ukraine Responsible for 300 Fatalities Since 1999

Posted: March 11th, 2015 in Accidents, Current Events, Video

The International Business Times reports that a Ukraine coal mine that recently had an accident that killed 34 miners is responsible for 300 fatalities since 1999. See the story at:

http://www.ibtimes.com/ukraine-coal-mine-explosion-more-300-killed-zasyadko-incidents-1999-1836044#.VPoRH_V1mdM.linkedin

The whole rescue process is being complicated by the fighting in the Ukraine.

Another story claim that investment in “safety technology” could have prevented the methane blast at the mine.

Press Release from the UK Rail Accident Investigation Branch: Bridge strike and collision between a train and fallen debris at Froxfield, Wiltshire, 22 February 2015

Posted: March 11th, 2015 in Accidents, Current Events, Investigations, Pictures

NewImageImage of debris on track before the collision, looking east.
Train 1C89 approached on the right-hand track
(image courtesy of a member of the public)

 Bridge strike and collision between a train and fallen debris at Froxfield, Wiltshire, 22 February 2015

RAIB is investigating a collision between a high speed train (HST) and a bridge parapet which had fallen onto the railway at Oak Hill, an unclassified road off the A4 on the edge of the village of Froxfield, between Hungerford and Bedwyn. The accident occurred at about 17:31 hrs on Sunday 22 February 2015, when the heavily loaded 16:34 hrs First Great Western service from London Paddington to Penzance (train reporting number 1C89) hit brick debris while travelling at about 90 mph (145 km/h). The train driver had no opportunity to brake before hitting the debris, and the impact lifted the front of the train. Fortunately, the train did not derail, and the driver applied the emergency brake. The train stopped after travelling a further 730 metres (800 yards). There were no injuries. The leading power car sustained underframe damage and there was damage to the train’s braking system.

The bridge parapet had originally been struck at about 17:20 hrs by a reversing articulated lorry. The lorry driver had turned off the A4 at a junction just north of the railway bridge, and crossed over the railway before encountering a canal bridge 40 metres further on which he considered to be too narrow for his vehicle. A pair of road signs located just south of the A4 junction warn vehicle drivers of a hump back bridge and double bends but there were no weight or width restriction signs. The lorry driver stopped before the canal bridge and attempted to reverse round a bend and back over the railway bridge without assistance, and was unaware when the rear of his trailer first made contact with, and then toppled, the brick parapet on the east side of the railway bridge. The entire parapet, weighing around 13 tonnes, fell onto the railway, obstructing both tracks. This was witnessed by a car driver who was travelling behind the lorry. The car driver left his vehicle to alert the lorry driver and he then contacted the emergency services by dialing 999 on his mobile phone at about 17:21 hrs. 

RAIB’s investigation will consider the sequence of events and factors that led to the accident. The investigation will include a review of the adequacy of road signage and the overall response to the emergency call made by the motorist who witnessed the collapse of the bridge parapet. It will identify any safety lessons from the accident and post-accident response.

RAIB’s investigation is independent of any investigations by the railway industry or safety authority. 

The RAIB will publish the findings at the conclusion of the investigation on it’s website.

Press Release from the Chemical Safety Board: CSB Releases Technical Analysis Detailing Likely Causes of 2010 Zinc Explosion and Fire at the Former Horsehead Zinc Facility in Monaca, Pennsylvania, that Killed Two Operators, Injured a Third

Posted: March 11th, 2015 in Accidents, Current Events, Investigations

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CSB Releases Technical Analysis Detailing Likely Causes of 2010 Zinc Explosion and Fire at the Former Horsehead Zinc Facility in Monaca, Pennsylvania, that Killed Two Operators, Injured a Third

Washington, DC, March 11, 2015 – The July 2010 explosion and fire at the former Horsehead zinc refinery in Monaca, Pennsylvania, likely resulted from a buildup of superheated liquid zinc inside a ceramic zinc distillation column, which then “explosively decompressed” and ignited, according to a technical analysis released today by the U.S. Chemical Safety Board (CSB).

Two Horsehead operators, James Taylor and Corey Keller, were killed when the column violently ruptured inside the facility’s refinery building, where multiple zinc distillation columns were operating.  The rupture released a large amount of zinc vapor, which at high temperatures combusts spontaneously in the presence of air.  The two men had been performing unrelated maintenance work on another nearby column when the explosion and fire occurred.  A third operator was seriously injured and could not return to work.

The incident was investigated by multiple agencies including the CSB and the U.S. Occupational Safety and Health Administration, but its underlying cause had remained unexplained.  In the fall of 2014, CSB contracted with an internationally known zinc distillation expert to conduct a comprehensive review of the evidence file, including witness interviews, company documents, site photographs, surveillance videos, laboratory test results, and data from the facility’s distributed control system (DCS).  The 57-page report of this analysis, prepared by Mr. William Hunter of the United Kingdom, was released today by the CSB.  Draft versions of the report were reviewed by Horsehead and by the United Steelworkers local that represented Horsehead workers in Monaca; their comments are included in the final report as appendices.

In the years following the 2010 incident, the Horsehead facility in Monaca was shut down and dismantled.  The “New Jersey” zinc process, a distillation-based method that was first developed in the 1920’s and was used for decades in Monaca, is no longer practiced anywhere in the United States, although a number of overseas companies, especially in China, continue to use it.

“Although this particular zinc technology has ceased being used in the U.S., we felt it was important to finally determine why this tragedy occurred,” said CSB Chairperson Dr. Rafael Moure-Eraso.  “Our hope is that this will at last provide a measure of closure to family members, as well as inform the safety efforts of overseas companies using similar production methods.”

The Hunter report was based on expert professional opinion, and did not involve any onsite examination of the evidence.  CSB investigators made several short deployments to the Horsehead site in 2010 following the incident, interviewing a number of witnesses and documenting conditions at the site.

The explosion involved an indoor distillation column several stories tall.  The column consisted of a vertical stack of 48 silicon carbide trays, topped by a reflux tower, and assembled by bricklayers using a specialized mortar.  The bottom half of the column was surrounded by a masonry combustion chamber fueled by natural gas and carbon monoxide waste gas.  Horsehead typically operated columns of this type for up to 500 days, at which time the columns were dismantled and rebuilt using new trays.

The explosion on July 22, 2010, occurred just 12 days after the construction and startup of “Column B.” Column B was used to separate zinc – which flowed as a liquid from the bottom of the column – from lower-boiling impurities such as cadmium, which exited as a vapor from the overhead line.  The column, which operated at more than 1600 °F, normally has only small amounts of liquid metals in the various trays, but flooding of the column creates a very hazardous condition, the analysis noted.  Such flooding likely occurred on July 22, 2010.

“Under extreme pressure the tray wall(s) eventually failed, releasing a large volume of zinc vapor and superheated zinc that would flash to vapor, and this pressure pushed out the combustion chamber blast panels,” Mr. Hunter’s report concluded.  “The zinc spray and vapor now had access to large amounts of workplace air and this created a massive zinc flame across the workplace.”

After examining all the data, the report determined that the explosion likely occurred because of a partial obstruction of the column sump, a drain-like masonry structure at the base of the column that had not been replaced when the column was rebuilt in June 2010.  The previous column that used this sump had to be shut down prematurely due to sump drainage problems, the analysis found.  These problems were never adequately corrected, and various problems with the sump were observed during the July 2010 startup of the new Column B.  Over at least an hour preceding the explosion, DCS data indicate a gradual warming at the base of Column B, as liquid zinc likely built up and flooded the lower trays, while vapor flow to the overhead condenser ceased.

Ten minutes before the explosion, an alarm sounded in the control room due to a high rate of temperature change in the column waste gases, as zinc likely began leaking out of the column into the combustion chamber, but by then it was probably too late to avert an explosion, according to the analysis.  Control room operators responded to the alarm by cutting the flow of fuel gas to Column B but did not reduce the flow of zinc into the column.  The unsafe condition of Column B was not understood, and operators inside the building were not warned of the imminent danger.

The technical analysis determined that there was likely an underlying design flaw in the Column B sump involving a structure known as an “underflow” – similar to the liquid U-trap under a domestic sink.  The small clearance in the underflow – just 65 millimeters or the height on one brick – had been implicated in other zinc column explosions around the world, and likely allowed dross and other solids to partially obstruct the sump and cause a gradual accumulation of liquid zinc in the column.  Liquid zinc in the column causes a dangerous pressure build-up at the bottom and impairs the normal evaporation of vapor, which would otherwise cool the liquid zinc.  Instead the liquid zinc becomes superheated by the heat from the combustion chamber, with the pressure eventually rupturing the column and allowing the “explosive decompression.”

The report noted that the Column B sump had previously been used with a different type of column that had a much lower rate of liquid run-off through the sump, so the problem with the sump was only exacerbated when Column B was constructed to separate zinc from cadmium, increasing the liquid flow rate into the sump by a factor of four to five.

The report concluded that Horsehead may have missed several opportunities to avoid the accident, overlooking symptoms of a blocked column sump that were evident days before the accident.  “Missing these critical points indicates that, in large measure, hazardous conditions at Monaca had been ‘normalized’ and that process management had become desensitized to what was going on.  This raises the question whether sufficient technical support was provided to the plant on a regular basis,” according to Mr. Hunter.

The report noted that New Jersey-type zinc distillation columns have been involved in numerous serious incidents around the world.  In 1993 and 1994, two column explosions at a former French zinc factory killed a total of 11 workers.  An international committee of experts who investigated the incidents in France identified up to 10 other major incidents at other sites attributable to sump drainage problems.  The Monaca facility had suffered five documented column explosions prior to 2010, but none with fatalities, according to the CSB-commissioned report.

For more information, contact Daniel Horowitz at (202) 261-7613 or (202) 441-6074 cell.

Root Cause Analysis Tip: Protecting Your Root Cause Analysis from Discovery – Work Product and Motivation

Posted: March 10th, 2015 in Investigations, Root Cause Analysis Tips

Saw an interesting short piece on McGuireWoods web site. It describe a case between Chevron Midstream Pipelines and Sutton Towing LLC. 

It seems the court decided that a “legally chartered” root cause analysis that was performed at the direction of in-house Chevron attorneys was not different from normal root cause analysis that the company performed after any incident.

Why? Because of the motivation to perform this root cause analysis was the same as any other RCA. The judge relied on several pieces of evidence:

  • A Chevron engineer “who agreed in her deposition that the ‘primary purpose of a root cause analysis’ is to ‘prevent a similar accident from happening again in the future,'” and “that it is ‘part of the Chevron ordinary course of business to conduct a root cause analysis’ after an incident.” 
  • “Chevron Pipeline’s President’s statement in an employee newsletter that ‘[w]e are conducting root cause analyses of both incidents and will apply lessons learned. Our ultimate goal remains the same – an incident and injury-free workplace.’”
  • “Chevron’s failure to provide the court examples of Chevron’s ordinary root cause analyses — noting that Chevron’s argument that its ordinary ‘incident reviews’ were different from its ‘legally chartered’ investigation ‘would be more convincing if there was actually another root cause analysis from which to distinguish the legally chartered one.'”

As Thomas Spahn, attorney from McGuireWoods wrote:

“To satisfy the work product motivation element, companies must demonstrate that they did something different or special because they anticipated litigation — beyond what they ordinarily would do, or which they were compelled to do by external or internal requirements.”

Of course, we always recommend that the statements in an incident report be carefully written and accurate. The words used can make a huge difference if your report is introduced as evidence in court.

Remember, what you write may not be interpreted or used as you intended it after the fact. An even if you think your investigation is protected as part of an attorney’s work product, the court may not agree.

Monday Accident & Lessons Learned: Using Additional Safeguards as Corrective Actions

Posted: March 9th, 2015 in Accidents, Current Events, Pictures

Screen Shot 2015 02 19 at 1 19 23 PM

Whenever you deal with a hazard, someone has to decide how many safeguards are enough.

Moving oil by tank cars is probably not the safest method of transporting oil. Pipelines are probably preferable. But pipelines don’t go from every oil source to every refinery. (And getting new pipelines permitted can be difficult – as we know.)

Rail accidents bring up the question … Should we be working on preventing the root causes of rail accidents OR should we be coming up with better safeguards (better rail cars) OR should we be working on getting more pipelines built as a longer term solution? 

Here’s the article from the Journal News that got me thinking about this issue:

Safer tank cars on CSX oil train didn’t prevent blast

 What do you think? What corrective actions would be SMARTER and what is enough? Leave your comments here.

 

 

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