The Center for Chemical Process Safety (CCPS) was founded in 1985 to develop technology and management practices that mitigate or eliminate process safety incidents in the chemical and petrochemical industries. Since that time, CCPS has published more than 100 books and held dozens of international conferences, each representing the most advanced thinking in process safety. CCPS is supported by the contributions and voluntary participation of more than 200 companies globally. CCPS is also the world's largest provider of undergraduate engineering curriculum materials through its SAChE program, with more than 160 universities participating from around the world.

Preface xxv

Acknowledgments xxvii

Acronyms and Abbreviations xxix

1 Introduction 1

1.1 Building on the Past 1

1.2 Investigation Basics 2

1.2.1 The First Step 2

1.2.2 The Second Step 4

1.2.3 The Third Step 4

1.2.4 The Fourth step 4

1.2.5 The Fifth Step 5

1.2.6 The Sixth Step 5

1.3 Who Should Read This Book? 5

1.4 The Guideline's Objectives 6

1.5 The Guideline's Content and Organization 6

1.6 The Continuing Evolution of Incident Investigation 11

2 Overview of Chemical Process Incident Causation 13

2.1 Stages of a Process-Related Incident 14

2.1.1 Three Phase Model of Process-Related Incidents 14

2.1.2 Event Tree 14

2.1.3 Swiss Cheese Model 16

2.1.4 Importance of Latent Failures 17

2.2 Key Causation Concepts 18

2.2.1 Loss of Containment or Energy 18

2.2.2 Management System Failure 20

2.2.3 Human Factors 21

2.2.4 Multiple Causation 22

2.2.5 Events vs Root Causes 22

2.2.6 Controlling Risk 23

2.3 Summary 24

3 An Overview of Investigation Methodologies 26

3.1 History of Investigation Methodologies and Tools 29

3.1.1 One-on-One Interview 29

3.1.2 Brainstorming 29

3.1.3 What If Analysis 30

3.1.4 5-Whys 30

3.1.5 Process of Elimination 31

3.1.6 Timelines 31

3.1.7 Sequence Diagrams 31

3.1.8 Predefined Trees 33

3.2 Tools for Use in Preparation for Root Cause Analysis 34

3.2.1 Timelines 34

3.2.2 Sequence Diagrams 35

3.2.3 Scientific Method 35

3.2.4 Causal Factor Identification 36

3.3 Structured Root Cause Analysis Methodologies 37

3.3.1 Checklists 37

3.3.2 Predefined Trees 38

3.3.3 Team-Developed Logic Trees 39

3.4 Selecting an Appropriate Methodology 43

3.4.1 Methodologies Used by CCPS Members 46

4 Designing An Incident Investigation Management System 47

4.1 System Considerations 49

4.1.1 An Organization's Responsibilities 49

4.1.2 Workforce Responsibilities 51

4.1.3 Role of the Management System Developers 53

4.1.4 Integration with Other Functions and Teams 54

4.1.5 Involvement by Regulatory Agencies 55

4.2 Typical Management System Topics 58

4.2.1 Classifying Incidents 58

4.2.2 Specifying and Managing Documentation 59

4.2.3 Legal Considerations 60

4.2.4 Describing Team Organization and Functions 63

4.2.5 Electronic Process Data and Control Systems 64

4.2.6 Defining Training Requirements 65

4.2.7 Emphasizing Root Causes 69

4.2.8 Fostering a Blame-Free Policy 70

4.2.9 Developing Recommendations 70

4.2.10 Recommendation Responsibilities 71

4.2.11 Implementing the Recommendations and Follow-up Activities 72

4.2.12 Providing a Template for Formal Reports 73

4.2.13 Management System Review and Approval 73

4.2.14 Planning for Continuous Improvement 73

4.3 Management System 74

4.3.1 Initial Implementation- Training 75

4.3.2 Developing a Specific Investigation Plan 75

5 Initial Notification, Classification and Investigation of Process Safety Incidents 79

5.1 Internal Reporting 79

5.2 Incident Classification 81

5.2.1 Severity Classification 82

5.2.2 Local Jurisdiction 89

5.2.3 Other Options for Establishing Classification Criteria 89

5.3 Incident Notification 90

5.3.1 Corporate Notification 90

5.3.2 Agency Notification 91

5.3.3 Other Stakeholder Notification 91

5.3.4 Other Notifications 92

5.4 Type of Investigation 92

5.4.1 Which Investigation System to Use? 92

5.4.2 Investigation Approach 93

5.5 Summary 94

6 Building and Leading An Incident Investigation Team 96

6.1 Team Approach 96

6.2 Advantages of the Team Approach 97

6.3 Leading a Process Safety Incident Investigation Team 98

6.4 Potential Team Composition 100

6.5 Building a Team for a Specific Incident 104

6.5.1 Composition and Size of Investigation Team 104

6.6 Team Activities 106

6.7 Summary 108

7 Witness Management 110

7.1 Overview 110

7.1.1 Witness Issues Following a Major Occurrence 111

7.1.2 Investigation Team Priorities for Managing Witnesses 112

7.2 Identifying Witnesses 113

7.3 Witness Interviews 115

7.3.1 Human Factors Related to Interviews 115

7.3.2 Collecting Information from Witnesses 118

7.3.3 Initial Witness Statements 120

7.3.4 Conducting the Interview 121

7.4 Conducting Follow-up Activities 134

7.5 Conducting Follow-up Interviews 135

7.6 Reliability of Witness Statements 135

7.7 Summary 135

8 Evidence Identification, Collection and Management 137

8.1 Overview 137

8.1.1 Developing a Specific Plan 138

8.1.2 Investigation Environment Following a Major Occurrence 139

8.1.3 Priorities for Managing an Incident Investigation Team 141

8.2 Sources of Evidence 144

8.2.1 Types of Sources 144

8.2.2 Physical Evidence and Data 147

8.2.3 Paper Evidence and Data 149

8.2.4 Electronic Evidence and Data 152

8.2.5 Position Evidence and Data 153

8.3 Evidence Gathering 156

8.3.1 Initial Site Visit 157

8.3.2 Identifying and Documenting Evidence 159

8.3.3 Tools and Supplies 162

8.3.4 Photography and Video 164

8.4 Timelines and Sequence Diagrams 168

8.4.1 Constructing a Timeline 168

8.4.2 Constructing a Sequence Diagram 174

8.5 Summary 176

9 Evidence Analysis and Causal Factor Determination 178

9.1 Scientific Method 178

9.2 Confirmation Bias 181

9.3 Evidence Analysis 181

9.3.1 Data Organization - Timelines 182

9.3.2 Use of Protocols 182

9.3.3 Mechanical Failure Analysis 184

9.3.4 Advanced Data Systems 187

9.4 Hypothesis Formulation 187

9.4.1 Fact/Hypothesis Matrix 188

9.5 Hypothesis Testing 190

9.5.1 Engineering Analysis 190

9.5.2 Computational Modeling 191

9.5.3 Reconstruction 191

9.5.4 Test the Items under Simulated Conditions 192

9.5.5 Testing of Human Input/Performance 192

9.6 Select the Final Hypothesis 193

9.6.1 Causal Factor Identification 193

9.6.2 Causal Factor Charting 198

9.6.3 Developing a Causal Factor Chart 200

9.7 Summary 202

10 Determining Root Causes-Structured Approaches 203

10.1 Concept of Root Cause Analysis 203

10.2 Case Histories 206

10.3 Methodologies for Root Cause Analysis 208

10.3.1 5 Whys Technique 208

10.3.2 Structured Root Cause Determination 212

10.4 Root Cause Determination Using Logic Trees 214

10.4.1 Gather Evidence and List Facts 215

10.4.2 Timeline Development 215

10.4.3 Logic Tree Development 215

10.5 Building a Logic Tree 219

10.5.1 Choosing the Top Event 220

10.5.2 Logic Tree Basics 220

10.5.3 Example-Chemical Spray Injury 228

10.5.4 What to Do if the Process Stalls 232

10.5.5 Guidelines for Stopping Tree Development 232

10.6 Example Applications 235

10.6.1 Fire and Explosion Incident-Fault Tree 235

10.6.2 Data-Driven Cause Analysis 239

10.6.3 Logic Tree Summary 241

10.7 Root Cause Determination Using Predefined Trees 242

10.7.1 Scenario Determination 244

10.7.2 Causal Factors 244

10.7.3 Predefined Tree 245

10.8 Using Predefined Trees 246

10.8.1 Predefined Tree Methodology 247

10.8.2 Example-Environmental Incident 248

10.8.2 Quality Assurance 255

10.8.3 Predefined Tree Summary 255

10.9 Checklists 256

10.9.1 Use of Checklists 257

10.9.2 Checklist Summary 258

10.10 Human Factors Applications 258

10.11 Summary 259

11 The Impact of Human Factors 261

11.1 Human Factors Concepts 262

11.2 Incorporating Human Factors into the Incident Investigation Process 267

11.2.1 Human Factors Before and During the Incident 268

11.2.2 Human Factors during the Causal Analysis 269

11.2.3 Human Factors in Developing Recommendations 275

11.2.4 After the Investigation 275

11.3 Other References 276

11.4 Summary 276

12 Developing Effective Recommendations 278

12.1 Key Concepts 278

12.2 Developing Effective Recommendations 280

12.2.1 Team Responsibilities 280

12.2.2 Attributes of Good Recommendations 280

12.3 Types of Recommendations 283

12.3.1 Inherently Safer Design 284

12.3.2 Layers of Protection 285

12.3.3 Commendation/Disciplinary Action 289

12.3.4 The "Further Action Required" Recommendation 289

12.4 The Recommendation Process 290

12.4.1 Select Each Cause 290

12.4.2 Perform a Completeness Test 290

12.4.3 Assessing the Effectiveness 291

12.4.4 Prepare to Present Recommendations 291

12.4.5 Review Recommendations with Management 293

12.4.6 Tracking and Closure of Recommendations 293

12.5 Summary 294

13 Preparing the Final Report 295

13.1 Report Scope 295

13.2 Interim Reports 296

13.3 Writing the Report 297

13.4 Sample Report Format 299

13.4.1 Executive Summary 300

13.4.2 Introduction 301

13.4.3 Background 301

13.4.4 Sequence of Events and Description of the Incident 302

13.4.5 Findings 302

13.4.6 Causal Factors 303

13.4.7 Root Causes 304

13.4.8 Recommendations 304

13.4.9 Noncontributory Factors 306