Student Book: 1. Session Objectives

CAUSAL TREE ANALYSIS 

STUDENT BOOK 1. Session Objectives Define the term accident and its general effects Define when to investigate and how to collect information for and use information from the investigation Define the term Causal Tree and its advantages and challenges Describe how to complete the four steps of Causal Tree including: How to list facts How to construct a Causal Tree (the necessary and sufficient test) How to target unacceptable facts How to decide upon appropriate actions to prevent recurrences Practice completing the four steps of a Causal Tree from example scenarios  

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2. What is is an accident?  n unexpected unexpected or undesirable undesirable event event that results or or could have resulted resulted in an in!ury or property damage 3. What types o accidents a!e possib"e? "alls to: same level lower level  

Caught: in# on# or  between ob!ects   

Contact with: chemicals electricity heat cold radiation     

$verexertion from: lifting pulling pushing   

%truc& against by: stationary or moving ob!ects protruding ob!ects  

 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

sharp or !agged ob!ects 'ubbed or irritated by: friction pressure vibration 

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odily reaction from: voluntary motion involuntary motion  

#. What a!e the costs$eects o an accident? mployee*"amily pain and suffering $rgani+ation ,or&ers Compensation Costs o 'eplacement labor costs o $ut of spec material o -orale o Production .uipment repair*replacement o Production stopped or slowed down o $%H# D$T# P# etc/ complaints*inspections o  

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%. Why do yo& 'ant to (no' 'hy an accident occ&!s? Prevent further non0conformances Protect employees %ave company money*protect !obs   

). *o' do yo& identiy the ca&ses o an accident? Perform an investigation +. When do yo& pe!o!, the investi-ation?  s soon as possible after it occurs "irst priority is to treat anyone in!ured and to protect other people from the accident source  

. Which incidents do yo& investi-ate? 'eportable in!uries and illnesses %erious spills or releases "irst aid cases 1ear misses with serious potential    

/. What types o ino!,ation sho&"d yo& co""ect? ac&ground 2nformation o ,here and when the incident occurred o ,ho and what were involved o ,itnesses 

 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

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 ccount of 2ncident %e.uence of events o xtent of damage o 2ncident type o o  pparent cause(s)

10. What types o ino!,ation sho&"d yo& !epo!t?  nalysis of accident  ctions ta&en or not ta&en# wor&place*environmental conditions# o management*supervisory policies# personal factors# etc/ 'ecommendations to prevent recurrence 2mmediate steps to prevent recurrence today o 3ong0term solutions that ensure systems modified to prevent future o recurrences "ollow0up to ensure actions successfully completed o 

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11. Witness nte!vie' Tips Consider preparing .uestions ahead of time 2nterview witnesses separately xplain purpose of investigation4 put witness at ease o  ccident prevention# not to establish fault  s& open0ended .uestions to get preliminary information 5se .uestions that begin with what# how# or why 3isten*Pay attention4 let the witness spea& freely4 be courteous and polite Ta&e notes without distracting the witness 5se .uestions starting with who# when# or which to focus in on details 5se s&etches and diagrams when appropriate to assist the witness mphasi+e areas of direct observation4 avoid hearsay e sincere4 do not argue with the witness 2f you don6t get helpful responses to open0ended .uestions# try using multiple choice .uestions such as what did you do first# stop the machine# call your supervisor# or try to clear it7 2f the witness gives unclear or imprecise answers# try to as& more specific .uestions o "or example if someone said he was going fast# what does fast mean7   

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12. What othe! types o evidence sho&"d yo& co""ect as pa!t o the investi-ation? Pictures 3abel them carefully as to when they were ta&en# from what o angle# and what do you thin& they show -aps and s&etches DC% information -easurements 

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 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

$thers7 13. *o' do yo& p!event !ec&!!ences o the incident? 1ote that most accidents may have 89 or more individual events that can be listed as causes/ "ortunately# most accidents can be prevented simply by eliminating one or more of the causes/ 

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1#. What is a a&sa" T!ee and can it ca&se an a""e!-ic !eaction? -ethod for analy+ing accident causes Team approach o 3ogic based o ey assumptions  n accident results from a combination of several causes o $ur goal is to identify causes and determine how to prevent further o accidents# not to find fault or to finger point 

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1% What a!e the e"e,ents o a a&sa" T!ee? Collect data "acts developed without interpretation or value !udgements o Develop logic tree 5se necessary and sufficient test o %elect organi+ational# human# and material targets Decide on appropriate actions and who will responsible for accomplishing them 

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1). What a!e the advanta-es o doin- a&sa" T!ee? "act based "ormal logic structure 5ses theory of multiple causes 'e.uires multi0element action plan 1ot finger pointing exercise Promotes concept of shared responsibility for accidents and corrective actions      

1+. What a!e the cha""en-es o &sin- a&sa" T!ee? Temptation to pre!udge facts Difficult to avoid drawing conclusions while building fact list %ome people have trouble initially converting to a structured logic system 'e.uires open participation in investigations 'e.uires broader acceptance of responsibility for accidents   

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1. Ove!vie' o the 4ethod  ssemble a team Develop a list of facts Construct a Causal Tree   

 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

2dentify target facts and select corrective actions 1/. Step 51 6 7sse,b"e a tea, 

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S&pe!viso! nj&!ed 8i avai"ab"e9 Health and %afety 'ep/* ca&sa" t!ee aci"itato!  ,itnesses $thers experienced in the !ob $ther departments (engineering# maintenance# etc/) %afety committee member $utside experts

20. Step 52 6 Deve"op a "ist o acts 3ist the facts one at a time o Do not ma&e value !udgements o  void negative reactions; o Do not interpret them 

21. Ti,ed :&i; 8 >

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Ea,p"e 52F

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$nly one outlet in office Cord ran from des& to wall Tripped on cord "ell

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 A systematic, logical approach to understanding and controlling accident causes

8

CAUSAL TREE ANALYSIS  Ea,p"e 53F

7

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1ot loo&ing in direction of travel umped into piping %ore shoulder  %craped forehead

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8

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Ea,p"e 5#F

7 >act AistF

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,rench slipped off nut ruised hand 1ot wearing gloves Hand hit pump base

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 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

Ea,p"e 5%F

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"act 3ist:

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Truc& loaded late Pump would not start Delivery to customer late Power failure

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"act 3ist: Deer on road Car could not stop Car hit deer  Car driving on road

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 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

2.*o' do identiy ta!-ets o! co!!ective action? "ind solutions to prevent the recurrence of the same or similar incidents/ ,hich facts are acceptable and which need to be avoided or prevented in the future7 

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2/.@&"es o th&,b 'hen se"ectin- Gta!-et actsH 3oo& for permanent solutions ,hen feasible# engineer out ha+ards o 1o ris& shifting 

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30.

Ta!-ets o! Eective So"&tions Targets are divided into three boxes: 

o o o

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31.

-aterial "actors $rgani+ational "actors Human "actors

Typically have at least one recommendation in each box Putting targets*recommendations in the right boxes is not as important as identifying all of them/ Don6t forget that you may have more than one recommendation action for each target box

Ea,p"es o O!-ani;ationa" So"&tions 2mprove preplanning process Clarify assignments or responsibilities 5pgrade training*share learning with other employees stablish or clarify procedure Change inspection fre.uencies or re.uirements Change preventative maintenance re.uirements     

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Ea,p"es o 4ate!ia" So"&tions -odify e.uipment design (materials of construction# si+e# etc/)  dd guarding  dd or change instrumentation and controls settings 2nstall ventilation4 reduce noise4 increase lighting    

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Ea,p"es o *&,an So"&tions 'e0train on procedure*!ob 2mprove ha+ard recognition s&ills 'esolve conflicting demands 2mprove clarity of directions -ore focus on implementing good practices related to &ey behaviors  dapt better body position Proper tool or e.uipment use 

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 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS  3#.

What sho&"d the action p"an "oo( "i(e?

"act Targeted

3%.

Preventative %olution

'esponsible Person

Date

Which acts 'o&"d yo& ta!-et?

>A/ SU44N U 6 AetIs -o th!o&-h a e' ea,p"es !o, sta!t to inish Ea,p"e 51 Dee! ncident

%id wo&e up at B:>9 -/ He had not heard his A:99 - alarm/ He &new it was not acceptable to be late to wor&/ He .uic&ly got dressed# brushed his teeth and hair# and rushed off to wor&/ (This was his usual way to wor&/) To ma&e up for lost time# he drove his car @< miles per hour on the road# even though the speed limit for the road was ?< miles per hour/ 2t was raining at that time and therefore the roads were wet/ s he was driving# he saw a deer on the road/ He could not stop his car and now ambi is motherless/ "act 3ist:

 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

Causal Tree:

Targets for Prevention

-aterial

$rgani+ational

Human

 ction 2tem

'esponsible Person

 A systematic, logical approach to understanding and controlling accident causes

Target Date

CAUSAL TREE ANALYSIS  Ea,p"e 52 The >i"te! ncident

 n 'C ngineer in!ured his right hand/ He cut his hand while cutting through a nylon strap with a poc&et &nife/ This in!ury re.uired seven stitches to close the wound4 therefore this is an $%H0recordable in!ury/ ,hen the engineer observed that filters he had ordered for a second plant had been delivered to the wrong plant# he decided to transport them to the correct plant in his truc&/ He loaded them into his truc& and used a ratchet strap as a rope to tie them down/ The ratchet had bro&en off the strap previously/ ,hen arrived at the second plant a few minutes later# he decided to use the Fuc&E poc&et &nife in his poc&et to cut through the strap/ He had used this &nife from time to time in the past to open boxes# etc/ He used his right hand to hold the filters away from the strap as he was cutting upward through the strap with his left hand/ ecause his &nife blade was dull# he had to apply extra force to cut through the strap/ ,hen the &nife cut through the strap# his momentum allowed the blade to contact his right hand/ 2ronically he had a pair of leather gloves in the front of his truc&/ The plant did not have any rules regarding the use of poc&et &nives/

Causal Tree

 A systematic, logical approach to understanding and controlling accident causes

CAUSAL TREE ANALYSIS 

Targets for Prevention

-aterial

$rgani+ational

Human

 ction 2tem

'esponsible Person

Target Date

Ea,p"e 53 The >o!-otten B"ind ncident

 t approximately :99 P-# the pipeline between the compressor and the downstream heat exchanger was over pressuri+ed causing a blind that was left in the line to tear apart/ The inner section of the blind separated from the outer ring between the flanges and impacted the tubes inside the downstream heat exchanger/ "ortunately no one was in!ured/ There was substantial damage to the downstream heat exchanger and several valves/ They had to be replaced before the plant could be started up/ 2n total# ?B hours of production were lost/ xample G> $n the evening of uly =