U.S. C HEMICAL S AFETY AND HAZARD INVESTIGATION BOARD

 HAZARD INVESTIGATION

 Report No. 2001-01-H

 Issue Date: October 2002

 IMPROVING REACTIVE HAZARD MANAGEMENT

KEY ISSUES:

• REGULATORY COVERAGE 

• NFPA HAZARD RATING SYSTEM

• MANAGEMENT SYSTEM GUIDANCE

• INDUSTRY INITIATIVES
Reactives Hazard Investigation 10-17-02

Contents

EXECUTIVE SUMMARY.................................................................................................................1

1.0 INTRODUCTION................................................................................................................17

1.1 Objectives............................................................................................................................18

1.2 Scope...................................................................................................................................19

1.3 Investigative Process.............................................................................................................19

1.4 Background..........................................................................................................................20

1.5 Stakeholder Involvement.......................................................................................................21

1.6 Public Hearing......................................................................................................................22

2.0 UNDERSTANDING REACTIVE HAZARDS.......................................................................25

2.1 Definition.............................................................................................................................25

2.2 Characterization of Reactive Hazards.....................................................................................26

3.0 PROFILE AND CAUSES OF REACTIVE INCIDENTS........................................................28

Napp Technologies...............................................................................................................28

Bartlo Packaging, Inc............................................................................................................29

3.1 Data Sources and Methods....................................................................................................29

3.2 Data Limitations...................................................................................................................30

3.3 Assessment of Reactive Incidents..........................................................................................34
Reactives Hazard Investigation 10-17-02

3.3.1 Injuries and Fatalities................................................................................................34

3.3.2 Consequences...........................................................................................................36

Whitehall Leather Company..................................................................................................37

3.3.3 Property Damage......................................................................................................38

Concept Sciences, Inc...........................................................................................................39

3.3.4 Public Impact...........................................................................................................40

3.4 Profile of Affected Industries.................................................................................................40

3.5 Profile of Reactive Incidents..................................................................................................42

3.5.1 Chemical Classes......................................................................................................42

3.5.2 Type of Reactions.....................................................................................................42

3.5.3 Type of Equipment ...................................................................................................43

BP Amoco Polymers, Inc......................................................................................................45

3.6 Common Reactive Hazards and Causal Information................................................................46

3.6.1 Reactive Hazards......................................................................................................46

3.6.2 Causal Information...................................................................................................46

4.0 NFPA HAZARD RATING SYSTEM....................................................................................48

5.0 REGULATORY ANALYSIS................................................................................................53

5.1 OSHA..................................................................................................................................53
Reactives Hazard Investigation 10-17-02

5.1.1 Overview.................................................................................................................53

5.1.2 Process Safety Management......................................................................................54

5.1.2.1 Development of PSM Standard....................................................................54

5.1.2.2 Process Safety Information and Process Hazard Analysis ..............................55

5.1.3 General Duty Clause.................................................................................................57

5.1.4 Other PSM Initiatives...............................................................................................57

5.2 EPA.....................................................................................................................................59

5.2.1 Overview.................................................................................................................59

5.2.2 Accidental Release Prevention Requirements (40 CFR 68)..........................................60

5.2.3 General Duty Clause.................................................................................................61

6.0 MANAGEMENT SYSTEM GUIDANCE..............................................................................63

6.1 Hazard Identification ............................................................................................................64

6.1.1 Existing Sources of Data ...........................................................................................65

6.1.2 Chemical Incompatibility ..........................................................................................66

6.1.3 Thermal Hazards......................................................................................................67

6.1.4 Chemical Reactivity Testing......................................................................................68

6.1.5 Accessibility of Chemical Reactivity Test Data ..........................................................69

6.2 Hazard Evaluation................................................................................................................69
Reactives Hazard Investigation 10-17-02

6.2.1 Quantitative Methods................................................................................................70

6.2.2 Qualitative Methods..................................................................................................71

6.3 Management of Change ........................................................................................................72

6.4 Personnel Training and Procedures........................................................................................73

6.5 Summary .............................................................................................................................74

7.0 INDUSTRY INITIATIVES...................................................................................................76

7.1 Responsible Care Process Safety Code...................................................................................76

7.1.1 Guidance on Implementation......................................................................................78

7.1.2 SOCMA Guidance on Implementation.........................................................................79

7.2 NACD Responsible Distribution Process................................................................................79

8.0 ALTERNATIVES FOR IMPROVING REGULATORY COVERAGE....................................81

8.1 Improved Coverage Under OSHA PSM.................................................................................81

8.1.1 Highly Reactive Substance Classification...................................................................81

8.1.2 Coverage Based on Hazard Evaluations .....................................................................82

8.1.3 “Safety Case” ..........................................................................................................83

8.2 Improved Coverage Under EPA RMP....................................................................................84

8.3 Regulatory Relief Absent Catastrophic Consequences............................................................84

8.4 Improvements in OSHA PSM and EPA RMP Requirements ...................................................85
Reactives Hazard Investigation 10-17-02

8.4.1 Improved Process Safety Information........................................................................85

8.4.2 Improved Process Hazard Analysis...........................................................................85

8.4.3 Improved Reporting Requirements............................................................................86

8.5 Regulatory Initiatives Under Review by New Jersey..............................................................86

9.0 CONCLUSIONS.................................................................................................................87

10.0 RECOMMENDATIONS.....................................................................................................89

11.0 REFERENCES....................................................................................................................96

APPENDIX A: GLOSSARY...........................................................................................................99

APPENDIX B: SURVEYS............................................................................................................ 105

B.1 Industry Survey................................................................................................................. 105

B.2 SOCMA Survey................................................................................................................ 106

APPENDIX C: SITE VISITS........................................................................................................ 107

C.1 Company Profiles.............................................................................................................. 107

C.2 Analysis of Practices for Reactive Chemical Hazard Management........................................ 108

APPENDIX D: RESOURCES....................................................................................................... 123

D.1 Guidelines......................................................................................................................... 123

D.2 Future Guidance ................................................................................................................ 125

D.3 ASTM Codes and Standards............................................................................................... 127
Reactives Hazard Investigation 10-17-02

D.4 Select Resources on Reactive Hazards................................................................................ 127

APPENDIX E: HAZARD INVESTIGATION DATA SOURCES.................................................... 130

APPENDIX F: STATISTICAL REVIEW OF OCCUPATIONAL FATALITIES.............................. 133

APPENDIX G: IDENTIFYING HAZARDS USING CHEMICAL REACTIVITY TESTING........... 135
Reactives Hazard Investigation 10-17-02

Figures

1 Case Study: Fire and Explosion, Napp Technologies Inc., April 21, 1995*

2 Case Study: Fire and Explosion, BPS Inc., May 8, 1997*

3 Total Incidents by Year, 1980–2001.......................................................................................34

4 Explosion, Terra Industries, December 13, 1994*

5 Fire and Explosion, Shell Chemical Company, May 27, 1994*

6 Categorization of Consequences of Incidents..........................................................................36

7 Case Study: Chemical Reaction, Cargo Transfer, Whitehall Leather Company, June 4, 1999*

8 Incidents Resulting in Large Property Losses..........................................................................38

9 Case Study: Explosion, Concept Sciences, Inc., February 19, 1999*

10 Industry Profile, 1980–2001 ..................................................................................................41

11 Fire and Explosion, Chief Supply Corporation, March 26, 1997*

12 Explosion, Georgia Pacific, September 10, 1997*

13 Equipment Involved in Incidents, 1980–2001 .........................................................................44

14 Case Study: Thermal Decomposition, BP Amoco Polymers, Inc., March 13, 2001*

15 NFPA Instability Rating Analysis, 1980–2001........................................................................48

*These photographs are not available for website posting. They will be placed in the printed copy.
Reactives Hazard Investigation 10-17-02

Tables

1 Limitations of Common Public Databases..........................................................................32

2 Incidents With Three or More Fatalities.............................................................................35

3 Common Classes of Chemicals Involved in Reactive Incidents...........................................42

4 Analysis of Causal Information.........................................................................................47

5 NFPA-Defined Degrees of Instability Hazards...................................................................50

6 ACC Responsible Care Safety Management Practices........................................................77

D-1 Select Resources on Reactive Hazards............................................................................. 128

F-1 Review of Occupational Fatalities................................................................................... 134
Reactives Hazard Investigation 10-17-02

Acronyms and Abbreviations

ACC American Chemistry Council

AFL-CIO American Federation of Labor-Congress of Industrial Organizations

AIChE American Institute of Chemical Engineers

AIHA American Industrial Hygiene Association

ANSI American National Standards Institute

API American Petroleum Institute

APELL Awareness and Preparedness for Emergencies at Local Level (UNEP)

ARC Accelerating rate calorimeter (Arthur D. Little, Inc.)

ARIP Accidental Release Information Program (EPA)

ASSE American Society of Safety Engineers

ASTM American Society for Testing and Materials

BLS U.S. Bureau of Labor Statistics

BPS Bartlo Packaging, Inc.

°C Degrees Celsius

CAAA Clean Air Act Amendments of 1990

CAER Community awareness and emergency response (ACC Responsible Care)

cal/g Calorie per gram

CCPS Center for Chemical Process Safety

CDCIR The Community Documentation Centre on Industrial Risk (MAHB)

CFR Code of Federal Regulations

CHETAH Chemical Thermodynamic and Energy Release Evaluation (ASTM)

CHRIS Chemical Hazards Response Information System (USCG)

CIMAH Control of Industrial Major Accident Hazards (U.K.)

CIRC Chemical Incident Reports Center (CSB)
Reactives Hazard Investigation 10-17-02

Acronyms and Abbreviations (cont’d)

COMAH Control of Major Accident Hazards Involving Dangerous Substances (U.K., 

replaced CIMAH in 1999)

CSB U.S. Chemical Safety and Hazard Investigation Board

CSI Concept Sciences, Inc.

DOE U.S. Department of Energy

DSC Differential scanning calorimetry

DTA Differential thermal analysis

EC European Community

EHS Environmental health and safety

EHS Extremely hazardous substance

EPA U.S. Environmental Protection Agency

EPCRA Emergency Planning and Community Right-to-Know Act

EU European Union

°F Degrees Fahrenheit

FMEA Failure modes and effects analysis

GDC General Duty Clause (OSHA)

HA Hydroxylamine

HarsNet Hazard Assessment of Highly Reactive Systems Thematic Network

HASTE The European Health and Safety Database

HAZOP Hazard and operability

HSE Health and Safety Executive (U.K.)

HSEES Hazardous Substances Emergency Events Surveillance (MAHB)

IAFF International Association of Fire Fighters
Reactives Hazard Investigation 10-17-02

Acronyms and Abbreviations (cont’d)

IChemE Institution of Chemical Engineers (U.K.)

ICWU International Chemical Workers Union (now part of UFCW)

IMIS Integrated Management Information System (OSHA)

IPD Instantaneous power density

ISA Instrumentation, Systems, and Automation Society

MAHB Major Accident Hazard Bureau (European Communities)

MARS Major Accident Reporting System (MAHB)

MHIDAS Major Hazard Incident Data Service (HSE)

MOC Management of change

MSDS Material safety data sheet

MSV Management systems verification

NACD National Association of Chemical Distributors

NAICS North American Industry Classification System

NFIRS National Fire Incident Reporting System

NFPA National Fire Protection Association

NIST National Institute of Standards and Technology

NOAA National Oceanic and Atmospheric Administration

NRC National Response Center (USCG)

NTSB National Transportation Safety Board

OCAW Oil, Chemical, and Atomic Workers (now part of PACE)

OSHA Occupational Safety and Health Administration

PACE Paper, Allied-Industrial, Chemical & Energy Workers International Union

PHA Process hazard analysis

PSCMS Process Safety Code Measurement System (ACC)
Reactives Hazard Investigation 10-17-02

Acronyms and Abbreviations (cont’d)

psi Pound per square inch

PSI Process safety information

PSM Process safety management (OSHA)

QA Quality assurance

R&D Research and development

RDP Responsible Distribution Process (NACD)

redox Oxidation-reduction

RMP Risk management program (EPA)

SIC Standard industrial classification

SOCMA Synthetic Organic Chemical Manufacturers Association

SOP Standard operating procedure

TCDD Dioxin

TCP 2,4,5-Tricholorophenol

TCPA Toxic Catastrophe Prevention Act (New Jersey)

TGA Thermogravimetric analysis

TNO Netherlands Organisation for Applied Scientific Research

UFCW United Food and Commercial Workers International Union

UNEP United Nations Environmental Programme

UNITE Union of Needletrades, Industrial, and Textile Employees

USCG U.S. Coast Guard

USWA United Steelworkers of America

VSP Vent size packaging

W/mL Watt per milliliter
Reactives Hazard Investigation 10-17-02, page 1

Executive Summary

ES.1 Introduction

The capability of chemical substances to undergo reactions, or transformations in their structure, is 

central to the chemical processing industry. Chemical reactions allow for a diversity of manufactured 

products. However, chemical reactivity can lead to significant hazards if not properly understood and 

controlled. 

Reactivity1 is not necessarily an intrinsic property of a chemical substance. The hazards associated 

with reactivity are related to process-specific factors, such as operating temperatures, pressures, 

quantities handled, concentrations, the presence of other substances, and impurities with catalytic 

effects. 

Safely conducting chemical reactions is a core competency of the chemical manufacturing industry. 

However, chemical reactions can rapidly release large quantities of heat, energy, and gaseous 

byproducts. Uncontrolled reactions have led to serious explosions, fires, and toxic emissions. The 

impacts may be severe in terms of death and injury to people, damage to physical property, and 

effects on the environment. In particular, incidents at Napp Technologies in 1995 and Morton 

International in 1998 raised concerns about reactive hazards to a national level. These and other 

incidents across the United States2 underscore the need to improve the management of reactive 

hazards. 

 

1

 See Appendix A, Glossary, for a definition of “reactivity” and numerous other technical terms.

2

 For example: BPS, Inc., West Helena, Arkansas (1997), with three fatalities; Condea Vista, Baltimore, 

Maryland (1998), with five injured; Whitehall Leather Company, Whitehall, Michigan (1999), with one fatality; 

and Concept Sciences, Inc., Allentown, Pennsylvania (1999), with five fatalities and 14 injured.
Reactives Hazard Investigation 10-17-02, page 2

A variety of legal requirements and regulations govern the hazards associated with highly hazardous 

chemicals (including reactive chemicals), among which are regulations of the Occupational Safety 

and Health Administration (OSHA) and the U.S. Environmental Protection Agency (EPA). 

OSHA develops and enforces standards to protect employees from workplace hazards. In the 

aftermath of the reactive incident that caused the Bhopal tragedy,3 OSHA was concerned about the 

possibility of a catastrophe at chemical plants in the United States. Its own investigations in the mid1980s indicated a need to look beyond existing standards. 

Bhopal and a series of other major incidents underscored the need for increased attention to process 

safety management; OSHA began to develop a standard that would incorporate these principles. A 

proposed standard was published in 1990. Additionally, the Clean Air Act Amendments (CAAA) of 

1990 required OSHA to promulgate a standard to protect employees from the hazards associated with 

releases of highly hazardous chemicals, including reactive chemicals. 

In 1992, OSHA promulgated its Process Safety Management (PSM) Standard (29 CFR 1910.119). 

The standard covers processes containing individually listed chemicals that present a range of 

hazards, including reactivity, as well as a class of flammable chemicals. Reactive chemicals were 

selected from an existing list of chemicals identified and rated by the National Fire Protection 

Association (NFPA) because of their instability rating of “3” or “4” (on a scale of 0 to 4).4,5 

CAAA also required EPA to develop regulations to prevent the accidental release of substances, 

including reactives, that could have serious effects on the public or the environment. In 1996, EPA

 

3

 On December 4, 1984, approximately 40 metric tons of methyl isocyanate was accidentally released in Bhopal 

India. The incident resulted in an estimated 2,000 deaths within a short period (Lees, 1996; App. 5).

4

 OSHA used the 1975 version of NFPA 49, Hazardous Chemicals Data. 

5An NFPA instability rating of “4” means that materials in themselves are readily capable of detonation or 

explosive decomposition or explosive reaction at normal temperatures and pressures. A rating of “3” means 

that materials in themselves are capable of detonation or explosive decomposition or explosive reaction, but 

require a strong initiating source or must be heated under confinement before initiation.
Reactives Hazard Investigation 10-17-02, page 3

promulgated its Accidental Release Prevention Requirements: Risk Management Programs (RMP; 

40 CFR 68) in response to the congressional mandate. Although this standard established new 

measures with regard to public notification, emergency response, and accident reporting, its 

requirements for managing process safety are similar to those of the OSHA PSM Standard. For 

purposes of this regulation, EPA identified covered substances based on toxicity and flammability–

but not chemical reactivity. 

Professional and trade associations such as the American Institute of Chemical Engineers (AIChE), 

the American Chemistry Council (ACC), the Synthetic Organic Chemical Manufacturers Association 

(SOCMA), and the National Association of Chemical Distributors (NACD) provide voluntary 

chemical process safety guidance to their members. 

In 1985, AIChE established the Center for Chemical Process Safety (CCPS) in response to the Bhopal 

tragedy. Manufacturers, government, and scientific research groups sponsor CCPS, which has 

published extensive industry guidance in the area of process safety technology and management. 

CCPS recently produced a safety alert on reactive hazards, and a more comprehensive product is 

under development. 

ACC and SOCMA each have programs to promote good practices among member companies in the 

area of chemical process safety. Similarly, NACD promotes good distribution practices and 

dissemination of information to end-use customers on the proper handling of chemical products. 

This report, Hazard Investigation: Improving Reactive Hazard Management, by the U.S. Chemical 

Safety and Hazard Investigation Board (CSB), examines chemical process safety in the United 

States–specifically, hazardous chemical reactivity. Its objectives are to: 

• Determine the impacts of reactive chemical incidents. 

• Examine how industry, OSHA, and EPA currently address reactive chemical hazards. 
Reactives Hazard Investigation 10-17-02, page 4

• Determine the differences, if any, between small, medium, and large companies with 

regard to reactive chemical policies, practices, in-house reactivity research, testing, and 

process engineering. 

• Analyze the appropriateness of, and consider alternatives to, industry and OSHA use of 

the NFPA instability rating system for process safety management. 

• Develop recommendations for reducing the number and severity of reactive chemical 

incidents. 

ES.2 Investigative Process

CSB completed the following tasks:

• Analyzed reactive incidents by collecting and reviewing available data. 

• Surveyed current reactive hazard management practices in industry. 

• Visited companies to observe reactive hazard management practices. 

• Analyzed regulatory coverage of reactive hazards.

• Met with stakeholders to discuss the problem and approaches to improve the management 

of reactive hazards.

• Conducted a public hearing at which further stakeholder inputs were solicited on key 

findings and preliminary conclusions from the hazard investigation.

The data analysis included evaluating the number, impact, profile, and causes of reactive incidents. 

CSB examined more than 40 data sources (e.g., industry and governmental databases and guidance 

documents; safety/loss prevention texts and journals; and industry association, professional society, 
Reactives Hazard Investigation 10-17-02, page 5

insurance, and academic newsletters), focusing on incidents where the primary cause was related to 

chemical reactivity. 

For the purposes of this investigation, an “incident” is defined as a sudden event involving an 

uncontrolled chemical reaction–with significant increases in temperature, pressure, and/or gas 

evolution–that has caused, or has the potential to cause, serious harm to people, property, or the 

environment.

Through a survey of select small, medium, and large companies, information was gathered about 

good practices for reactive hazard management within the chemical industry. CSB also visited 

chemical industry facilities that have implemented programs for managing reactive hazards. 

ES.3 Key Findings 

1. The limited data analyzed by CSB include 167 serious incidents in the United States 

involving uncontrolled chemical reactivity from January 1980 to June 2001. Forty-eight of 

these incidents resulted in a total of 108 fatalities. The data include an average of six injuryrelated incidents per year, resulting in an average of five fatalities annually. 

2. Nearly 50 of the 167 incidents affected the public.6

3. Over 50 percent of the 167 incidents involved chemicals not covered by existing OSHA or 

EPA process safety regulations.7

 

6

“ Public impact” is defined as known injury, offsite evacuation, or shelter-in-place.

7

 OSHA PSM Standard (29 CFR 1910.119) and EPA Accidental Release Prevention Requirements: Risk 

Management Programs (RMP) Under the Clean Air Act, Section 112(r)(7) (40 CFR 68).
Reactives Hazard Investigation 10-17-02, page 6

4. Approximately 60 percent of the 167 incidents involved chemicals that either are not rated by 

NFPA or have “no special hazard” (NFPA “0”).8 Only 10 percent of the 167 incidents 

involved chemicals with NFPA published ratings of “3” or “4.”

5. For the purpose of the OSHA PSM Standard, NFPA instability ratings have the following 

limitations with respect to identifying reactive hazards:

• They were originally designed for initial emergency response purposes, not for 

application to chemical process safety.

• They address inherent instability only, not reactivity with other chemical substances (with 

the exception of water) or chemical behavior under nonambient conditions.

• NFPA Standard 499–on which the OSHA PSM-listed highly reactive chemicals are 

based–covers only 325 chemical substances, a very small percentage of the chemicals 

used in industry.10

• The OSHA PSM Standard lists 137 highly hazardous chemicals–only 38 of which are 

considered highly reactive based on NFPA instability ratings of “3” or “4.”

• The NFPA ratings were established by a system that relies, in part, on subjective criteria 

and judgment. 

 

8An NFPA instability rating of “0” means that materials in themselves are normally stable, even under “fire” 

conditions.

9

 NFPA 49, Hazardous Chemicals Data (1975 Edition). 

10 The Chemical Abstracts Service maintains data on over 200,000 chemicals that are listed under national and 

international regulations.
Reactives Hazard Investigation 10-17-02, page 7

6. As a result of the joint OSHA-EPA chemical accident investigation of the Napp Technologies 

incident in April 1995, a recommendation was made by EPA and OSHA to consider adding 

more reactive chemicals to their respective lists of chemicals covered by process safety 

regulations. To date, neither OSHA nor EPA process safety regulations have been modified 

to better cover reactive hazards.

7. Reactive hazards are diverse. The reactive incident data analyzed by CSB included:

• Over 40 different chemical classes (i.e., acids, bases, monomers, oxidizers, etc.), with no 

single dominating class. 

• Several types of hazardous chemical reactivity, with 36 percent attributed to chemical 

incompatibility, 35 percent to runaway reactions, and 10 percent to impact-sensitive or 

thermally sensitive materials.

• A diverse range of chemical process equipment–including reaction vessels, storage tanks, 

separation equipment, and transfer equipment. Storage and process equipment 

(excluding chemical reaction vessels) account for over 65 percent of the equipment 

involved; chemical reaction vessels account for only 25 percent.

Reactive incidents can result in a variety of consequences, including fire and explosions (42 

percent of incidents) as well as toxic gas emissions (37 percent). 

8. No one comprehensive data source contains the data needed to adequately understand root 

causes and lessons learned from reactive incidents or other process safety incidents. 

9. Incident data collected by OSHA and EPA provide no functional capability to track reactive 

incidents so as to analyze incident trends and develop preventive actions at a national level.
Reactives Hazard Investigation 10-17-02, page 8

10. Causes and lessons learned are reported in only 20 percent of the 167 incidents. (Industry 

associations, government agencies, and academia typically do not collect this information.) 

However, more than 60 percent of the incidents for which some causal information was 

available involved inadequate practices for identifying hazards or conducting process hazard 

evaluations; nearly 50 percent involved inadequate procedures for storage, handling, or 

processing of chemicals.11

11. Over 90 percent of the incidents analyzed by CSB involved reactive hazards that are 

documented in publicly available literature accessible to the chemical processing and 

handling industry.12

12. Although several computerized tools13 and literature resources are available to identify 

reactive hazards, surveyed companies do not generally use them. In some cases, these tools 

provide an efficient means of identifying reactive hazards without the need for chemical 

testing.

13. Surveyed companies share chemical data of a general nature for most chemicals (e.g., 

material safety data sheets [MSDS]) and good handling practices for some. However, 

detailed reactive chemical test data, such as thermal stability data–which can be valuable in 

identifying reactive hazards–are not typically shared.

14. Approximately 70 percent of the 167 incidents occurred in the chemical manufacturing 

industry. Thirty percent involved a variety of other industrial sectors that store, handle, or 

use chemicals in bulk quantities.

 

11The summation of causal factor statistics exceeds 100 percent because each major incident can, and often 

does, have more than one cause. 

12 See Section 6.1 for a list of selected literature.

13National Oceanic and Atmospheric Administration’s (NOAA) The Chemical Reactivity Worksheet, 

American Society for Testing and Materials’ (ASTM) CHETAH, and Bretherick’s Database of Reactive 

Chemical Hazards. 
Reactives Hazard Investigation 10-17-02, page 9

15. Only limited guidance on the management of reactive hazards throughout the life cycle of a 

chemical manufacturing process14 is currently available to industry through professional 

societies, standards organizations, government agencies, or trade associations. There are 

significant gaps in the following:

• Unique aspects of reactive hazards that should be examined during process hazard 

analysis (PHA), such as the need for reactive chemical test data, and methods to identify 

and evaluate worst case scenarios involving uncontrolled reactivity. 

• Integration of reactive hazard information into process safety information, operating 

procedures, training, and communication practices.

• Review of the impact on reactive hazards due to proposed changes in chemical processes. 

• Concise guidance targeted at companies engaged primarily in the bulk storage, handling, 

and use of chemicals to prevent inadvertent mixing of incompatible substances. 

16. Several voluntary industry initiatives, such as ACC’s Responsible Care and NACD’s 

Responsible Distribution Process(RDP), provide guidance on process safety management for 

chemical manufacturers and distributors. However, no voluntary industry initiatives list 

specific codes or requirements for reactive hazard management. 

17. The EPA RMP regulation and the European Community’s Seveso II directive both exempt 

covered processes from some regulatory provisions, if the facility documents the absence of 

catastrophic damage from process accidents under reasonable worst case conditions. The

 

14A recently initiated CCPS project, Managing Reactive Chemical Hazards, may address this gap in industry 

guidance. 
Reactives Hazard Investigation 10-17-02, page 10

State of New Jersey is also considering similar action in its proposed revisions of the Toxic 

Catastrophe Prevention Act (TCPA) regulations.

ES.4 Conclusions

1. Reactive incidents are a significant chemical safety problem. 

2. The OSHA PSM Standard has significant gaps in coverage of reactive hazards because it is 

based on a limited list of individual chemicals with inherently reactive properties. 

3. NFPA instability ratings are insufficient as the sole basis for determining coverage of reactive 

hazards in the OSHA PSM Standard. 

4. The EPA Accidental Release Prevention Requirements (40 CFR 68) have significant gaps in 

coverage of reactive hazards. 

5. Using lists of chemicals is an inadequate approach for regulatory coverage of reactive 

hazards. Improving reactive hazard management requires that both regulators and industry 

address the hazards from combinations of chemicals and process-specific conditions rather 

than focus exclusively on the inherent properties of individual chemicals.

6. Reactive incidents are not unique to the chemical manufacturing industry. They also occur in 

many other industries where chemicals are stored, handled, or used.

7. Existing sources of incident data are not adequate to identify the number, severity, and causes

of reactive incidents or to analyze incident frequency trends.

8. There is no publicly available database for sharing lessons learned from reactive incidents.

9. Neither the OSHA PSM Standard nor the EPA RMP regulation explicitly requires specific 

hazards, such as reactive hazards, to be examined when performing a process hazard analysis. 
Reactives Hazard Investigation 10-17-02, page 11

Given that reactive incidents are often caused by inadequate recognition and evaluation of 

reactive hazards, improving reactive hazard management involves defining and requiring 

relevant factors (e.g., rate and quantity of heat and gas generated) to be examined within a 

process hazard analysis. 

10. The OSHA PSM Standard and the EPA RMP regulation do not explicitly require the use of 

multiple sources when compiling process safety information. 

11. Publicly available resources15 are not always used by industry to assist in identifying reactive 

hazards.

12. There is no publicly available database to share reactive chemical test information.

13. Current good practice guidelines on how to effectively manage reactive hazards throughout 

the life cycle 16 of a chemical manufacturing process are neither complete nor sufficiently 

explicit.

14. Given the impact and diversity of reactive hazards, optimum progress in the prevention of 

reactive incidents requires both enhanced regulatory and nonregulatory programs.

 

15 NOAA’s The Chemical Reactivity Worksheet, ASTM’s CHETAH, and Bretherick’s Database of Reactive 

Chemical Hazards.

16“Life cycle” refers to all phases of a chemical manufacturing process–from conceptualization, process 

research and development (R&D), engineering design, construction, commissioning, commercial operation, and 

major modification to decommissioning.
Reactives Hazard Investigation 10-17-02, page 12

ES.5 Recommendations

Occupational Safety and Health Administration (OSHA)

1. Amend the Process Safety Management (PSM) Standard, 29 CFR 1910.119, to achieve more 

comprehensive control of reactive hazards that could have catastrophic consequences. 

• Broaden the application to cover reactive hazards resulting from process-specific 

conditions and combinations of chemicals. Additionally, broaden coverage of hazards 

from self-reactive chemicals. In expanding PSM coverage, use objective criteria. 

Consider criteria such as the North American Industry Classification System (NAICS), a 

reactive hazard classification system (e.g., based on heat of reaction or toxic gas 

evolution), incident history, or catastrophic potential. 

• In the compilation of process safety information, require that multiple sources of 

information be sufficiently consulted to understand and control potential reactive hazards. 

Useful sources include: 

- Literature surveys (e.g., Bretherick’s Handbook of Reactive Chemical Hazards, Sax’s

Dangerous Properties of Industrial Materials).

- Information developed from computerized tools (e.g., ASTM’s CHETAH, NOAA’s 

The Chemical Reactivity Worksheet).

- Chemical reactivity test data produced by employers or obtained from other sources 

(e.g., differential scanning calorimetry, thermogravimetric analysis, accelerating rate 

calorimetry). 

- Relevant incident reports from the plant, the corporation, industry, and government.

- Chemical Abstracts Service.
Reactives Hazard Investigation 10-17-02, page 13

• Augment the process hazard analysis (PHA) element to explicitly require an evaluation of 

reactive hazards. In revising this element, evaluate the need to consider relevant factors, 

such as:

- Rate and quantity of heat or gas generated.

- Maximum operating temperature to avoid decomposition.

- Thermal stability of reactants, reaction mixtures, byproducts, waste streams, and 

products.

- Effect of variables such as charging rates, catalyst addition, and possible 

contaminants.

- Understanding the consequences of runaway reactions or toxic gas evolution.

2. Implement a program to define and record information on reactive incidents that OSHA 

investigates or requires to be investigated under OSHA regulations. Structure the collected 

information so that it can be used to measure progress in the prevention of reactive incidents 

that give rise to catastrophic releases. 

U.S. Environmental Protection Agency (EPA) 

1. Revise the Accidental Release Prevention Requirements, 40 CFR 68 (RMP), to explicitly 

cover catastrophic reactive hazards that have the potential to seriously impact the public, 

including those resulting from self-reactive chemicals and combinations of chemicals and 

process-specific conditions. Take into account the recommendations of this report to OSHA 

on reactive hazard coverage. Seek congressional authority if necessary to amend the 

regulation.
Reactives Hazard Investigation 10-17-02, page 14

2. Modify the accident reporting requirements in RMP*Info to define and record reactive 

incidents. Consider adding the term “reactive incident” to the four existing “release events”

in EPA’s current 5-year accident reporting requirements (Gas Release, Liquid 

Spill/Evaporation, Fire, and Explosion). Structure this information collection to allow EPA 

and its stakeholders to identify and focus resources on industry sectors that experienced the 

incidents; chemicals and processes involved; and impact on the public, the workforce, and the 

environment. 

National Institute of Standards and Technology (NIST) 

Develop and implement a publicly available database for reactive hazard test information. Structure 

the system to encourage submission of data by individual companies and academic and government 

institutions that perform chemical testing.

Center for Chemical Process Safety (CCPS)

1. Publish comprehensive guidance on model reactive hazard management systems. At a 

minimum, ensure that these guidelines cover:

• For companies engaged in chemical manufacturing: reactive hazard management, 

including hazard identification, hazard evaluation, management of change, inherently 

safer design, and adequate procedures and training.

• For companies engaged primarily in the bulk storage, handling, and use of chemicals: 

identification and prevention of reactive hazards, including the inadvertent mixing of 

incompatible substances. 

2. Communicate the findings and recommendations of this report to your membership. 
Reactives Hazard Investigation 10-17-02, page 15

American Chemistry Council (ACC) 

1. Expand the Responsible Care Process Safety Code to emphasize the need for managing 

reactive hazards. Ensure that:

• Member companies are required to have programs to manage reactive hazards that 

address, at a minimum, hazard identification, hazard evaluation, management of change, 

inherently safer design, and adequate procedures and training.

• There is a program to communicate to your membership the availability of existing tools, 

guidance, and initiatives to aid in identifying and evaluating reactive hazards.

2. Develop and implement a program for reporting reactive incidents that includes the sharing of 

relevant safety knowledge and lessons learned with your membership, the public, and 

government to improve safety system performance and prevent future incidents.

3. Work with NIST in developing and implementing a publicly available database for reactive 

hazard test information. Promote submissions of data by your membership.

4. Communicate the findings and recommendations of this report to your membership.

Synthetic Organic Chemical Manufacturers Association (SOCMA)

1. Expand the Responsible Care Process Safety Code to emphasize the need for managing 

reactive hazards. Ensure that:

• Member companies are required to have programs to manage reactive hazards that 

address, at a minimum, hazard identification, hazard evaluation, management of change, 

inherently safer design, and adequate procedures and training.
Reactives Hazard Investigation 10-17-02, page 16

• There is a program to communicate to your membership the availability of existing tools, 

guidance, and initiatives to aid in identifying and evaluating reactive hazards.

2. Develop and implement a program for reporting reactive incidents that includes the sharing of 

relevant safety knowledge and lessons learned with your membership, the public, and 

government to improve safety system performance and prevent future incidents.

3. Work with NIST in developing and implementing a publicly available database for reactive 

hazard test information. Promote submissions of data by your membership.

4. Communicate the findings and recommendations of this report to your membership.

National Association of Chemical Distributors (NACD)

1. Expand the existing Responsible Distribution Process to include reactive hazard management 

as an area of emphasis. At a minimum, ensure that the revisions address storage and 

handling, including the hazards of inadvertent mixing of incompatible chemicals.

2. Communicate the findings and recommendations of this report to your membership.

International Association of Firefighters 

Paper, Allied-Industrial, Chemical & Energy Workers International Union 

(PACE)

The United Steelworkers of America

Union of Needletrades, Industrial, and Textile Employees (UNITE)

United Food and Commercial Workers International Union

American Society of Safety Engineers (ASSE)

American Industrial Hygiene Association (AIHA)

Communicate the findings and recommendations of this report to your membership. 
Reactives Hazard Investigation 10-17-02, page 17

1.0 Introduction

Safely conducting chemical reactions is a core competency of the chemical industry.17 However, 

chemical reactions can become uncontrolled, rapidly releasing large quantities of heat, energy, and 

gaseous byproducts. As highlighted below, uncontrolled reactions have led to serious explosions, 

fires, and toxic emissions. 

In April 1995, an explosion and fire at Napp Technologies, in Lodi, New Jersey, killed five 

employees, injured several others, destroyed a majority of the facility, significantly damaged nearby 

businesses, and resulted in the evacuation of 300 residents from their homes and a school (USEPAOSHA, 1997). Additionally, firefighting generated chemically contaminated water that ran off into a 

river. The property damage exceeded $20 million. 

Two years later, an explosion and fire at Bartlo Packaging (BPS, Inc.), in West Helena, Arkansas, 

killed three firefighters and seriously injured another. Hundreds of residents, including patients at a 

local hospital, were either evacuated or sheltered-in-place (USEPA-OSHA, 1999). Property damage 

was extensive. Major roads were closed; and Mississippi River was traffic halted for nearly 12 hours. 

An incident on April 8, 1998, at Morton International, Inc., in Paterson, New Jersey, resulted in nine 

injuries. Residents in a 10- by 10-block area around the plant sheltered-in-place for up to 3 hours, 

and an estimated 10,000 gallons of contaminated water ran off into a nearby river (USCSB, 2000). 

Six months later, an explosion and fire at Condea Vista, in Baltimore, Maryland, injured five and 

caused $14 million in damages (USCSB, 2001). In February 1999, an explosion at Concept Sciences, 

Inc. (CSI), in Allentown, Pennsylvania, killed five persons, including one worker at an adjacent 

business (USCSB, 2002a). Fourteen persons, including six firefighters, were injured. The facility

 

17 See Appendix A, Glossary, for definition of technical terms.
Reactives Hazard Investigation 10-17-02, page 18

was completely destroyed, and several other businesses in the vicinity suffered significant property 

damage. The blast also shattered windows of homes in a nearby residential area. In June 1999, a 

toxic release at Whitehall Leather in Whitehall, Michigan, killed one employee (NTSB, 2000).

Each of these incidents involved an uncontrolled chemical reaction. They vividly illustrate the tragic 

potential of reactive hazards and offer compelling reasons to improve reactive hazard management. 

1.1 Objectives

The U.S. Chemical Safety and Hazard Investigation Board (CSB) conducted this investigation of 

reactive hazard management in the United States to: 

• Determine the impacts of reactive chemical incidents. 

• Examine how industry, the Occupational Safety and Health Administration (OSHA), and 

the U.S. Environmental Protection Agency (EPA) currently address reactive chemical 

hazards. 

• Determine the differences, if any, between small, medium, and large companies with 

regard to reactive chemical policies, practices, in-house reactivity research, testing, and 

process engineering. 

• Analyze the appropriateness of, and consider alternatives to, industry and OSHA use of 

the National Fire Protection Association (NFPA) instability rating system for process 

safety management. 

• Develop recommendations for reducing the number and severity of reactive chemical 

incidents. 
Reactives Hazard Investigation 10-17-02, page 19

This report, Improving Reactive Hazard Management, supports the CSB goal of increasing awareness 

of reactive hazards and reducing the occurrence of reactive incidents. 

1.2 Scope

In addressing reactive hazard management in the United States, this investigation focuses on: 

• Chemical manufacturing–from raw material storage through chemical processing to 

product storage. 

• Other industrial activities involving bulk chemicals, such as storage/distribution, waste 

processing, and petroleum refining. 

Industrial activities involving transportation, pipelines, laboratories, minerals extraction, mining, 

explosives manufacturing, pyrotechnic manufacturing, or military uses are not considered. 

1.3 Investigative Process

The chemical industry evaluates the reactivity of a substance in a variety of ways. With input from 

key stakeholders, CSB developed the following definition of a reactive incident (synonymous with 

“reactive chemical incident”): 

A sudden event involving an uncontrolled chemical reaction–with significant 

increases in temperature, pressure, or gas evolution–that has caused, or has the 

potential to cause, serious harm to people, property, or the environment.18

 

18 The use of the term “sudden” is intended to imply that reactive incidents–though they may be slow to develop 

because of reactive chemistry effects over an extended time–have sudden consequences. 
Reactives Hazard Investigation 10-17-02, page 20

Using this definition, CSB analyzed data to attempt to determine the number, impact, profile, 

and causes of reactive incidents.

Hazards arising from reactive chemicals are covered by a variety of legal requirements and 

regulations, including regulations of OSHA and EPA. CSB examined these authorities and 

regulations to determine how reactive hazards are currently addressed.

Through site visits and a survey of select small, medium, and large companies (Appendices B and 

C)–and literature reviews of industry guidance documents–CSB gathered information on the strengths 

and limitations of reactive hazard management practices within the chemical industry. Industry 

facilities with programs for managing reactive hazards were selected for site visits. 

1.4 Background

On April 8, 1998, a runaway reaction during the production of Automate Yellow 96 dye initiated a 

sequence of events that led to an explosion and fire at the Morton International, Inc., plant in 

Paterson, New Jersey. On the day of the incident, flammable materials were released as the result of 

an uncontrolled rapid temperature and pressure rise in a 2,000-gallon kettle in which orthonitrochlorobenzene and 2-ethylhexylamine were being reacted. Nine employees were injured in the 

explosion and fire, including two seriously. Potentially hazardous materials were released into the 

community, and the physical plant was extensively damaged. 

The CSB Morton investigation showed that inadequate evaluation and communication of reactive 

hazards was one important factor in the root and contributing causes of the incident (USCSB, 2000). 

During the course of the investigation, stakeholders raised concerns and requested further 

investigation into reactive hazards–particularly in light of similar incidents since 1995. 
Reactives Hazard Investigation 10-17-02, page 21

Occasionally, in the course of conducting incident investigations, CSB is alerted to significant safety 

problems that are beyond the scope of any one particular incident investigation. The Morton 

investigation validated stakeholder concerns that reactive hazards merited a more systemic analysis. 

Therefore, CSB recommended in its report that a hazard investigation be conducted to study issues 

associated with the management of reactive hazards. A CSB hazard investigation examines 

numerous incidents to better understand the nature and causes of a generic safety problem. 

1.5 Stakeholder Involvement

CSB sought input from various stakeholders to gain insight into differing approaches on how to 

improve reactive hazard management. CSB staff met with industry, regulatory agencies, professional 

safety organizations, trade associations, trade unions, and public advocacy groups. 

The following stakeholders contributed to this investigation: 

• American Chemistry Council (ACC).

• Center for Chemical Process Safety (CCPS).

• Environmental Defense.

• U.S. Environmental Protection Agency (EPA).

• International Association of Firefighters.

• National Association of Chemical Distributors (NACD).

• National Fire Protection Association (NFPA).

• Occupational Safety and Health Administration (OSHA).

• Paper, Allied-Industrial, Chemical & Energy Workers International Union (PACE).

• Synthetic Organic Chemical Manufacturers Association (SOCMA).
Reactives Hazard Investigation 10-17-02, page 22

• The Chlorine Institute, Inc. 

• The United Steelworkers of America.

• Union of Needletrades, Industrial, and Textile Employees (UNITE).

• United Food and Commercial Workers International Union (UFCW).

• Working Group on Community Right-to-Know.

1.6 Public Hearing

A public hearing was held on May 30, 2002, at the Paterson, New Jersey, City Hall to communicate 

findings and conclusions from this hazard investigation and to gather input from interested parties 

prior to making final recommendations and issuing a final report. 

The following questions were published in the Federal Register and were the main focus of the public 

hearing:

• Is there a need to improve coverage of potentially catastrophic reactive hazards under the 

OSHA Process Safety Management (PSM) Standard? If so, what approaches should be 

pursued?

- What criteria could be used in the context of process safety regulations to classify 

chemical mixtures as “highly hazardous” due to chemical reactivity? 

- Should there be a minimum regulatory requirement for reactive hazard identification 

and evaluation that apples to all facilities engaged in chemical manufacturing?

- What are alternative regulatory approaches?
Reactives Hazard Investigation 10-17-02, page 23

• For processes already covered under the OSHA PSM Standard, do the safety 

management requirements of the standard adequately address reactive hazards? If not, 

what should be added or changed?

• Does the EPA Risk Management Program (RMP) regulation provide sufficient coverage 

to protect the public and the environment from the hazards of reactive chemicals? If not, 

what should be added or changed?

• What nonregulatory actions should OSHA and EPA take to reduce the number and 

severity of reactive chemical incidents?

Additional issues: 

• Suggested improvements to industry guidance or initiatives (e.g., Responsible Care

[ACC], Responsible Distribution Process[RDP; NACD]) to reduce the number and 

severity of reactive chemical incidents.

• Suggested improvements for sharing reactive chemical test data, incident data, and 

lessons learned.

• Other nonregulatory initiatives that would help prevent reactive incidents.

CSB staff presented the investigation findings and preliminary conclusions to the Board. The public 

hearing agenda also included panels representing industry, labor, the State of New Jersey, and 

technical experts in the field of chemical process safety. In addition, the hearing included eyewitness 

testimony from victims of reactive chemical incidents. Former Senator Frank Lautenberg (D-NJ) and 

Senator Jon Corzine (D-NJ) gave statements of support for the hazard investigation. Representatives 

from OSHA and EPA declined an invitation to participate. 
Reactives Hazard Investigation 10-17-02, page 24

Following the hearing, a 30-day period was opened to receive written public comments. All 

information gathered at the hearing and written public comments were carefully considered before the 

final report was approved by the Board. 
Reactives Hazard Investigation 10-17-02, page 25

2.0 Understanding Reactive Hazards

Reactive hazards are briefly defined and characterized below. However, neither Section 2.0 nor this 

report in its entirety is intended to substitute for any of the more extensive guides and references on 

this topic or to eliminate the need for expert analysis in dealing with reactive hazards. 

2.1 Definition 

Process safety management of reactive hazards involves the systematic identification, evaluation, and 

control of hazardous chemical reactivity at all phases of the process life cycle–from research and 

development (R&D) to pilot plant, commercial operation, change management, and 

decommissioning. It encompasses many types of industrial chemical operations–from storage and 

handling to chemical manufacturing and waste processing. 

CCPS (1989) defines a “hazard” as a chemical or physical condition that has the potential to cause 

harm to human life, property, or the environment. A “reactive hazard” has the potential to lead to a 

reactive incident (Section 1.3). 

There are several types of hazardous chemical reactivity. A reactive hazard may involve:

• Impact-sensitive or thermally sensitive materials (i.e., self-reactive chemicals)–When 

subjected to heat or impact, these chemicals may rapidly decompose, resulting in a 

potentially explosive release of energy. 

• Runaway reactions (i.e., self-reactive chemicals or mixtures)–In an out-of-control 

reaction involving a chemical or chemical mixture, the rate at which heat is generated 

exceeds the rate at which it is removed through cooling media and surroundings.
Reactives Hazard Investigation 10-17-02, page 26

• Chemical incompatibility between two or more substances–These hazards occur when a 

chemical is suddenly mixed or comes into contact with another chemical, resulting in a 

violent reaction.

Among governmental regulations, voluntary guidelines, or trade association codes of practice, there is 

no standard approach to classifying hazardous chemical reactivity. A variety of methods are used to 

address self-reactivity (e.g., decomposition reactions and some polymerization reactions) and 

chemical incompatibility. 

For the purposes of this investigation–rather than adopting any single definition of a “reactive 

chemical”–CSB focuses on the broadest range of practices to identify reactive hazards and to manage 

the risk of reactive incidents. A reactive chemical may include any pure substance or mixture that has 

the capability to create a reactive incident. CSB defines a reactive incident as a sudden event 

involving an uncontrolled chemical reaction–with significant increases in temperature, pressure, or 

gas evolution–that has caused, or has the potential to cause, serious harm to people, property, or the 

environment.

2.2 Characterization of Reactive Hazards

A reactive hazard exists when changes in chemical structure have the potential to generate heat, 

energy, and gaseous byproducts beyond that which can be safely absorbed by the immediate 

surroundings (Bretherick, 1999). If the rate of energy release is rapid enough and not adequately 

controlled, the consequences may be severe and include fires, explosions, or toxic emissions. 

Numerous types of chemical reactions pose potential hazards. Literature and incident data highlight 

the hazards of common industrial reactions, such as polymerization, decomposition, acid-base, 

oxidation-reduction (redox), and reactions with water. Polymerization and decomposition can be 

classified as “self-reactions” because they often involve just one chemical substance. However, other 
Reactives Hazard Investigation 10-17-02, page 27

substances acting unexpectedly–such as catalysts or contaminants–are often required to promote even 

these reactions. “Chemical incompatibility” requires that two or more substances come into contact. 

A reactive hazard may involve further, more complicated behavior when an intended chemical 

reaction releases enough heat and energy to initiate a second unintended reaction, usually a chemical 

decomposition. 

Therefore, chemical reactivity is not necessarily an intrinsic property of a single chemical substance. 

The severity of reactive hazards is influenced by process-specific factors, such as operating 

temperatures, pressures, quantities handled, chemical concentrations, impurities with catalytic effects, 

and compatibility with other chemicals onsite.

Section 6.0 and Appendix D discuss good practices and guidelines for reactive hazard management. 
Reactives Hazard Investigation 10-17-02, page 28

3.0 Profile and Causes of Reactive Incidents 

The purpose of the CSB data search and analysis was to better understand the impact of reactive incidents 

by evaluating their number, severity, and causes. Five recent reactive incidents–which illustrate the 

diversity of reactive hazards–are highlighted throughout this section. 

Napp Technologies

On April 21, 1995, an explosion and fire at Napp Technologies in Lodi, New Jersey, killed five 

employees and destroyed the facility (Figure 1).19 The plant was conducting a toll blending 

operation to produce a commercial gold precipitation agent. The chemicals involved were water 

reactive (i.e., aluminum powder, a combustible metal in the form of finely divided particles; and 

sodium hydrosulfite, a combustible solid). 

During the process operation, water was introduced into the blender, probably as a result of a 

mechanical failure. Operators noticed the production of heat and the release of foul-smelling gas. 

During an emergency operation to offload the blender of its reacting contents, the material ignited 

and a deflagration occurred. The most likely cause of this incident was the inadvertent 

introduction of water into water-reactive materials (USEPA-OSHA, 1997).

NFPA rates aluminum powder as “1” and sodium hydrosulfite as “2” for reactivity. Therefore, 

these chemicals are not included on the OSHA PSM list and are not regulated under that standard. 

The product of the mixture of aluminum powder and sodium hydrosulfite–a gold precipitation 

agent–is not rated by NFPA. However, a material safety data sheet (MSDS) on the chemical 

from the company contracting with Napp to produce the material gave it an NFPA rating of “3.” 

 

19 Photograph not available for website posting; it will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 29

The Napp incident raises questions regarding use of the NFPA rating system as the sole basis for 

regulating reactive hazards (see Section 5.1.3). 

Bartlo Packaging, Inc. 

This incident occurred on May 8, 1997 (Figure 2).20 BPS–a bulk storage and distribution facility 

in West Helena, Arkansas–was repackaging an organic pesticide, AZM50W. As it was being 

offloaded into a warehouse, employees noticed smoke coming from the building. City 

emergency response personnel were notified. A team of four West Helena firefighters was 

attempting to locate the source of the smoke when an explosion occurred. A collapsing 

cinderblock wall killed three of the firefighters, and one was injured.

The most likely cause of the incident was the decomposition of bulk sacks of the pesticide, which 

had been placed too close to a hot compressor discharge pipe, and the release of flammable 

vapors (USEPA-OSHA, 1999). This case history illustrates that severe reactive incidents can 

occur even at companies engaged in the simple storage and handling of chemicals. The facility 

was not covered by OSHA PSM, and AZM50W does not have an NFPA rating.

3.1 Data Sources and Methods 

CSB searched over 40 data sources for incidents that met its definition of a reactive incident (Section 2.1). 

The data search focused on recent incidents (since 1980) where the primary cause was related to chemical 

reactivity; however, the 1980 cutoff is not intended to diminish the important lessons learned from prior 

incidents. The search covered both chemical manufacturing (i.e., raw material storage, chemical 

processing, and product storage) and other industrial activities involving bulk chemicals, such as 

 

20 Photograph not available for website posting; it will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 30

storage/distribution, waste processing, and petroleum refining.21 For purposes of this incident search, 

only reactive incidents that caused serious consequences22 were examined. 

Sources of incident data include a variety of public -domain databases, technical literature, and news 

accounts (Appendix E). Sources are categorized in Appendix E as “reviewed only” if incident data did 

not meet the CSB definition of “reactive chemical incident” (Section 1.3). 

3.2 Data Limitations 

Although the statistics provided in Section 3.3 concerning the number and severity of reactive incidents 

are grave, existing sources of incident data are inadequate to identify the number, severity, frequency, and 

causes of reactive incidents. The following limitations affected CSB analysis of incident data: 

• No single data source provides a comprehensive collection of chemical incidents from which 

to retrieve or track reactive incident data. 

• Incident data collected by OSHA and EPA provide no functional capability to track the 

occurrence of reactive incidents with serious worker or public impacts;23 such data are a 

valuable resource for analyzing incident trends and developing prevention actions at a 

national level.

 

21 Incidents involving transportation, pipelines, laboratories, minerals extraction, mining, explosives manufacturing, 

pyrotechnic manufacturing, or military uses are beyond the scope of this investigation, in addition to events 

involving simple combustion (i.e., rapid reaction of fuel [liquid, vapor, or dust] with oxygen in air). 

22 Serious consequences are injuries or fatalities, significant property damage, environmental contamination, and 

offsite evacuation or shelter-in-place.

23 Research indicates that the OSHA Integrated Management Information System (IMIS) identified 70 percent of the 

reactive incidents in Section 3.3, but none were tracked as “reactive incidents.” Only 25 percent of the reactive 

incidents that occurred from June 1994 through June 1999 were reported to EPA. These reports are contained in the 

RMP 5-year accident histories sent to EPA prior to the June 1999 deadline for initial submissions.
Reactives Hazard Investigation 10-17-02, page 31

• No one comprehensive data source contains the data needed to adequately understand root 

causes and lessons learned from reactive incidents or other process safety incidents.24

Table 1 lists the limitations of some public databases. 

• It is difficult to identify causes and lessons learned in existing sources of process safety 

incident data because industry associations, government agencies, and academia generally do 

not collect this information. 

• Data sources contained incomplete and sometimes inaccurate incident information–for 

example, on numbers of injuries and community impacts. Descriptions of incidents and 

causal information were sometimes vague and incomplete.

• There are limited Federal or state requirements to report incidents unless they involve specific 

consequences.

The results of the CSB incident data analysis are acknowledged as representing only a sampling of recent 

reactive incident data. This limitation precludes CSB from drawing statistical conclusions on incidence 

rates or inferring trends in the number or severity of incidents. However, despite these limitations, the 

data can be used to illustrate the profile and causes of reactive incidents.

 

24 Only one publicly available database is designed to provide such information. The Accident Database from the 

Institution of Chemical Engineers (IChemE) contains lessons learned for one-fourth of the 12,000 incidents in the 

database.
Reactives Hazard Investigation 10-17-02, page 32

Table 1

Limitations of Common Public Databases

Data Source (a) Description Years Searched Strengths Limitations

USCG NRC 

Data on release 

notifications of oil and 

hazardous substance 

reports to NRC or EPA 

regional offices

1982-Present

Extensive range of incidents, 

including those resulting in a 

chemical release from a 

reactive incident

All states and localities 

included

Knowledge of incident limited at time 

of notification, leading to possible 

inaccuracies 

No requirement to follow up on reports 

to improve data quality

Relies on company compliance to 

notify (or third party)

Notificatio n requirement is driven by 

release of specified chemical above 

reportable quantity

Not designed to be a lessons-learned 

database

OSHA IMIS

Records of workplace 

inspections, including 

those prompted by 

accidents where a worker 

is injured

1984-Present

Information from OSHA field 

inspections, a third party

More accurate description of 

impacts on employees and

contractors

Keyword indexing allows for 

easy search and retrieval

Not comprehensive, limited to 

incidents selected by OSHA

Inspections without abstracts cannot be 

keyword searched; causal information 

unavailable

Designed to assist compliance 

enforcement, not to report on incident 

causes

Limited information from “State-Plan” 

states

Not designed to be a lessons-learned 

database

EPA ARIP

Responses to 

questionnaires sent by 

EPA from facilities that 

have had significant 

releases; purpose is to 

learn about causes and 

consequences of hazardous 

material incidents

1986-Present

Supplements NRC reports for 

more significant events

Additional information on

causal factors, consequences, 

and company safety programs

Data are easily analyzed for 

common causes

Includes all states and localities 

Survey relies on voluntary compliance

Not comprehensive; limited to select 

cases

Checklist approach limits value of 

information to understand root cause

Not designed to be a lessons-learned 

database
Reactives Hazard Investigation 10-17-02, page 33

EPA RMP*Info

Data about chemical 

releases resulting in 

specific impacts covered 

under RMP regulation (40 

CFR 68)

1994-Present

Provides further information 

about major events involving 

specific listed chemicals

More accurate data on impacts, 

causal factors, and corrective 

actions

Includes all states and localities 

Not comprehensive, limited to events 

resulting in major harm for a select 

group of chemicals

None of selected chemicals were listed 

due to reactivity

No requirements to include extensive 

description of incidents, including 

causes and lessons learned

Checklist approach limits respondent’s 

choices (no indicator for incidents 

resulting from reactive hazards)

Not designed to be a lessons-learned 

database

IChemE 

Accident 

Database

Reports about chemical 

incidents around the world 

from official government 

sources, the news media, 

and company reports 

1980 - Present

Scope is beyond incidents 

reported to or investigated by 

regulatory agencies or first 

responders

Contains lessons learned from 

3,000 incidents

Only one-fourth of the 12,000 

incidents in the database contain 

lessons-learned information

HSE MHIDAS

Information taken from 

public domain sources 

worldwide; however, 

majority of the 7,000 

incidents occurred either in 

UK or US

1985 - Present

Scope is beyond incidents 

reported to or investigated by 

regulatory agencies or first 

responders

No extensive description of incidents, 

including causes and lessons learned

U.S. Fire 

Administration 

NFIRS

Response data submitted 

by local fire departments 1980-Present

Includes fire and explosion 

incidents with no/little release, 

incidents resulting in property 

damage only, and near-misses if 

fire department was called

Limited state participation

Represents limited information 

available to fire department at time of 

response

Checklist approach limits respondent 

choices

Not designed to be a lessons-learned 

database

CSB CIRC

Initial reports about 

chemical incidents around 

the world from official 

government sources, news 

media, and eyewitnesses 

1998-Present

Scope is beyond incidents 

reported to or investigated by 

regulatory agencies or first 

responders

Includes domestic and 

international incidents

Not comprehensive, only select 

incidents included

Limited time span

Frequent reliance on media accounts 

limits the depth of initial reports

Not designed to be a lessons-learned 

database

(a) ARIP = Accidental Release Information Program; CIRC = Chemical Incident Reports Center; HSE = Health and Safety 

Executive, United Kingdom; IChemE = Institution of Chemical Engineers; IMIS = Integrated Management Information System; 

MHIDAS = Major Hazard Incident Data Service; NFIRS = National Fire Incident Reporting System; NRC = National Response 

Center; RMP = Risk Management Program.
Reactives Hazard Investigation 10-17-02, page 34

3.3 Assessment of Reactive Incidents 

Reactive incidents can severely affect workers and the public, as well as cause major economic losses and 

environmental damage. The limited data available to CSB includes 167 incidents over nearly 22 years, as 

summarized in Figure 3. 

 

0

2

4

6

8

10

12

14

16

18

20

80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01

Year

No. of Incidents

167 incidents since 

1980, an average of 8 

incidents per year

Figure 3. Total incidents by year, 1980–2001.

3.3.1 Injuries and Fatalities

Of the 167 reactive incidents, 48 caused a total of 108 fatalities. Since 1980, CSB data show an average 

of six injury-related incidents per year, resulting in an average of five fatalities per year. Table 2 provides 

data on 12 incidents with three or more fatalities (see also Figures 4 and 5).25 Appendix F presents a 5-

year summary of U.S. Bureau of Labor Statistics data on occupational fatalities.

 

25 Photographs not available for website posting; they will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 35

Table 2

Incidents With Three or More Fatalities

Location Date Fatalities

ARCO Chemical 

Channelview, TX (a) 07/05/90 17

Albright and Wilson 

Charleston, SC 06/17/91 9

IMC Fertilizer/Angus Chemical 

Sterlington, LA 05/01/91 8

NAPP Technologies 

Lodi, NJ 04/21/95 5

Concept Sciences 

Hanover Township, PA 02/19/99 5

Terra Industries 

Port Neal, IA 12/13/94 4

Bastian Plating 

Auburn, IN 06/28/88 4

Plastifax 

Gulfport, MS 06/02/82 3

Merck 

Barceloneta, Puerto Rico 06/12/86 3

Shell Chemical 

Belpre, OH 05/27/94 3

BPS Inc. 

West Helena, AR 05/08/97 3

BP Amoco 

Augusta, GA 03/13/01 3

(a) Although this incident involved combustion, an uncontrolled peroxide decomposition reaction created an 

oxygen-enriched atmosphere in a tank containing flammable liquids. This incident does not meet the “simple 

combustion” exclusion in the CSB reactive incident definition because it involved combustion in an oxygenenriched atmo sphere rather than oxygen in air. 
Reactives Hazard Investigation 10-17-02, page 36

3.3.2 Consequences 

In addition to causing injuries and fatalities to plant personnel and the public, reactive incidents can also 

result in environmental harm and equipment damage. These impacts may be due to fires, explosions, 

hazardous liquid spills, toxic gas releases, or any combination of such (Figure 6). Fires and explosions 

are the most frequent occurrence in CSB data, followed by toxic gas releases. 

Fire/explosion:

42%

Hazardous liquid spill:

5%

Fire/explosion and 

toxic release:

16%

Toxic gas release:

37%

Figure 6. Categorization of consequences of incidents.

167 total incidents
Reactives Hazard Investigation 10-17-02, page 37

Whitehall Leather Company

On June 4, 1999, the inadvertent mixing of two incompatible chemicals caused a toxic gas release 

at Whitehall Leather Company in Whitehall, Michigan (Figure 7).26 One person was killed, and 

another was injured.

A truck driver arrived at the facility to deliver a load of sodium hydrosulfide solution. The 

delivery took place on the night shift. During prior deliveries on this shift, the shift supervisor 

had received only “pickle acid.” (The material commonly known onsite as pickle acid was 

actually ferrous sulfate.) He assumed that the sodium hydrosulfide was pickle acid and directed 

the truck driver to unload at the facility’s pickle acid tank. Hydrogen sulfide gas was produced 

when the sodium hydrosulfide solution was unloaded into the ferrous sulfate tank. The truck 

driver was exposed to the gas and died; one Whitehall Leather employee was injured (NTSB, 

2000). 

The Whitehall Leather case demonstrates that reactive hazards other than thermal runaways in

reactors–such as inadvertent mixing of incompatible materials–can cause severe reactive 

incidents. Neither ferrous sulfate nor sodium hydrosulfide is rated by NFPA, and neither 

compound is an OSHA PSM-listed chemical.

 

26 Photograph not available for website posting; it will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 38

3.3.3 Property Damage

At least a dozen incidents in the CSB data resulted in property damage alone exceeding $10 million, with 

three cases in which loss exceeded $100 million (Figure 8).27 These numbers do not include further 

financial losses due to business interruption or lost market share.

$120

$105 $100

$80

$32

$25 $20 $20 $20 $16 $15 $14 $12 $12 $10 $10

$0

$20

$40

$60

$80

$100

$120

$140

$160

Port Neal, IA

Sterlington,

LA

Belpre, OH

Seadrift, TX

Alvin, TX

Philadelphia,

PA

Pasadena,

TX

Martinez, CA

Lodi, NJ

Chicago

Heights, IL

Torrance, CA

Baltimore,

MD

Channelview,

TX

Seadrift, TX

Greens

Bayou, TX

Charleston,

SC

12/94 05/91 05/94 03/91 01/92 03/82 03/00 01/97 04/95 02/81 11/87 10/98 07/90 07/80 07/81 06/91

Property Loss ($MM)

Figure 8. Incidents resulting in large property losses.

 

27 Property loss figures are quoted for the year in which they were incurred. The numbers in Figure 8 are not scaled 

to represent constant dollar valuation of loss.
Reactives Hazard Investigation 10-17-02, page 39

Concept Sciences, Inc. 

An explosion that occurred during the distillation of a solution of aqueous hydroxylamine (HA) 

and potassium sulfate killed four CSI employees and an employee of an adjacent business on 

February 19, 1999 (Figure 9,28 USCSB, 2002a). Fourteen people were injured. The CSI facility, 

in Hanover Township, Pennsylvania, was completely destroyed. Several local buildings in the 

industrial park were damaged, and windows were broken in nearby residences. 

On the day of the incident, CSI was in the process of producing its first full-scale batch of 50 wtpercent HA. After the distillation process was shut down, the HA contained in one of the process 

tanks explosively decomposed. The last recorded concentration of the HA solution in the tank 

was 86 wt-percent. HA has been shown to explosively decompose at high concentrations (i.e., 85 

wt-percent; Koseki and Iwata, 2001). 

The CSB investigation determined that CSI did not adequately evaluate the hazards of HA during 

process development. The explosive decomposition hazard of HA was not adequately translated 

into CSI’s process design, operating procedures, mitigation measures, or precautionary 

instructions for operators. This incident demonstrates the need for effective reactive hazard 

management throughout the many phases of the process life cycle–including development, 

design, construction, and startup. Furthermore, the offsite fatality dramatically illustrates that 

reactive incidents can affect the public.HA is not a listed chemical under the EPA RMP 

regulation. It is an OSHA PSM-listed chemical and has an NFPA rating of “3.”

 

28 Photograph not available for website posting; it will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 40

3.3.4 Public Impact 

Reactive incidents primarily cause onsite impacts, such as worker fatalities and injuries–and severe 

business impacts, including lost production and property damage. However, a significant number of 

incidents have led to public impacts,29 which include public harm (injury or fatality), offsite evacuation, 

or shelter-in-place. Nearly 50 of the 167 incidents in the CSB data affected the public. At least eight of 

the 12 reactive incidents listed in Table 2 had public impacts. One of these incidents (CSI) resulted in a 

public fatality. 

3.4 Profile of Affected Industries 

Analysis of CSB data shows that reactive incidents are not unique to the chemical manufacturing industry 

(Figure 10). Although about 70 percent of the 167 incidents occurred in the chemical industry, the 

remaining 30 percent occurred in other industries that use bulk quantities of chemicals–such as waste 

processing and petroleum refining. 

The BPS incident is an example of a severe reactive incident at a nonchemical manufacturing site. The 

fire and explosion at Chief Supply Corporation also occurred at a nonchemical manufacturing facility 

(Figure 11).30 

 

29 The definition of public impact is based on the criteria for reporting offsite incidents in the EPA RMP regulation 

(40 CFR 68.42a). “Public” includes anyone except employees or contractors at the facility.

30 Photograph not available for website posting; it will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 41

Chemical manufacturing:

66%

Other

34%

Unknown:

1%

Bulk storage/handling 

(not otherwise specified):

27%

Petroleum refining:

2%

Waste processing:

3%

Storage:

1%

Figure 10. Industry profile, 1980–2001.

167 total incidents
Reactives Hazard Investigation 10-17-02, page 42

3.5 Profile of Reactive Incidents 

3.5.1 Chemical Classes

The CSB data analysis shows that reactive incidents are not limited to any one chemical or to a few 

classes of chemicals. Table 3 lists common chemical classes involved in the 167 incidents. None of these 

classes represent a majority of incidents in the CSB data. 

Table 3

Common Classes of Chemicals Involved in Reactive Incidents 

Chemical Class No. of Incidents (a)

 Acid 38

 Oxidizer 20

 Monomer 15

 Water 14

 Base 12

 Organic peroxide 12

 Hypochlorite 10

 Alcohol 8

 Hydrocarbon 7

 Inorganic/metal 6

 Hydrosulfite 6

 Other classes 79

(a) Some incidents involved mo re than one class of chemicals.

3.5.2 Type of Reactions

A range of chemical reactions can cause reactive incidents. Over 90 percent of the 167 incidents analyzed 

by CSB involved reactive hazards that are documented in literature available to the chemical processing 

industry (see Section 7.1). The various types of reactions indicate the diversity of chemistry involved; for 
Reactives Hazard Investigation 10-17-02, page 43

example, an explosion at a Georgia Pacific resin factory–involving formaldehyde, phenol, and sulfuric 

acid–was caused by an exothermic runaway reaction (Figure 12).31. Nearly 75 percent of the incidents 

from the CSB data were caused by one of the following types of reactions:

• Decomposition (26 percent)

• Acid/base (11 percent)

• Water reactive (10 percent) 

• Polymerization (10 percent) 

• Oxidation (6 percent) 

• Decomposition initiated by another reaction (5 percent) 

• Oxidation-reduction (4 percent) 

• Chlorination, catalytic cracking, halogenation, hydrolysis, and nitration (each 1 percent).

Information was insufficient to determine type of reaction for the remaining 23 percent of incidents. 

3.5.3 Type of Equipment

A reactive incident can occur in most equipment used to store, handle, manufacture, and transport 

chemicals. The CSB data show that incidents occur in a variety of chemical processing and storage 

equipment–including reactors, storage tanks, and bulk storage drums (Figure 13). Twenty-five percent of 

the incidents involved reactor vessels; 22 percent, storage equipment (e.g., tanks, rail cars, and designated 

storage areas); 22 percent, other process equipment (e.g., holding tanks, mixers, and dryers); 13 percent, 

 

31 Photograph not available for website posting; it will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 44

waste, separation, and transfer equipment; and 10 percent, bulk storage drums. No particular equipment 

accounted for 8 percent of the data. 

These data contradict a common assumption that a majority of reactive incidents involve chemical reactor 

vessels. Chemical processing and storage equipment (excluding reactors) and bulk storage drums account 

for over 65 percent of the equipment involved in reactive incidents. The case histories highlighted 

throughout Section 3.0 are examples of reactive incidents that did not occur in reaction vessels. 

Transfer equipment:

5%

Reactor:

25%

Storage equipment:

22% Other process 

equipment:

22%

Separation equipment:

5%

Unknown:

8%

Stroage drum:

10%

Waste equipment:

3%

Figure 13. Equipment involved in incidents, 1980–2001.

167 total incidents
Reactives Hazard Investigation 10-17-02, page 45

BP Amoco Polymers, Inc.

On March 13, 2001, three people were killed as the result of a vessel failure and fire at the BP 

Amoco Polymers plant in Augusta, Georgia (Figure 14,32 USCSB, 2002b). The facility produces 

plastics. Startup operations in a process to produce Amodel–a nylon-family polymer–were 

suspended due to problems with equipment in a finishing line. During the aborted startup 

attempt, polymer was discarded into the polymer catch tank, a waste collection vessel. Cooling 

effects created a layer of hardened plastic 3 to 5 inches thick along the entire inner wall of the 

vessel, blocking all normal and emergency vents. However, the material in the core of the vessel 

remained hot and molten. It continued to react and decompose, generating gas that could not 

escape. Over several hours, the catch tank became pressurized. The failure occurred as workers 

attempted to open a cover on the vessel. 

The CSB investigation determined that BP Amoco was unaware of the hazardous reaction 

chemistry of the polymer because of inadequate hazard identification during process 

development. This lack of awareness is a commonly cited cause of reactive incidents within the 

CSB data. The BP Amoco incident also involved an endothermic (or heat consuming) reaction 

rather than the more commonly recognized exothermic (or heat producing) runaway chemical 

reaction.

 

32 Photograph not available for website posting; it will appear in the printed copy.
Reactives Hazard Investigation 10-17-02, page 46

3.6 Common Reactive Hazards and Causal Information 

Identifying common types of associated hazards and causes is an essential element of understanding the 

reactive incident problem. 

3.6.1 Reactive Hazards

A common perception is that reactive incidents are primarily the result of runaway reactions. In fact, 

analysis of data from the 167 incidents suggests that other types of reactive hazards should also be of 

concern. CSB data analysis identified three common types of reactive hazards (see Appendix A for 

definitions): 

• Chemical incompatibility 

• Runaway reaction

• Impact or thermally sensitive materials.

Of the 167 incidents, 36 percent are attributed to chemical incompatibility, 35 percent to runaway 

reactions, and 10 percent to impact or thermally sensitive materials. The hazard is unknown for 19 percent 

of the incidents. 

3.6.2 Causal Information 

Causal33 data are reported for only 37 of the 167 incidents. Analysis of this limited set of data revealed a 

variety of causes (Table 4). More than 60 percent of reactive incidents for which some causal information 

was available involved inadequate management systems for identifying or evaluating hazards. In the CSI 

 

33 The term “cause” within this section refers to inadequate process safety management practices. The causal 

information presented is not intended to be considered as root causes; no consistent root cause analysis methods 

were identified within the data.
Reactives Hazard Investigation 10-17-02, page 47

incident, even though the reactive hazard was known, an inadequate hazard evaluation was performed. 

Nearly 50 percent of the causal data also point to inadequate procedures for the safe storage, handling, or 

processing of chemicals (e.g., Whitehall Leather and BPS).

Table 4

Analysis of Causal Information 

Causes Frequency of Attribution

No. of Incidents Incidents With Causal 

Information (%) (a) (b)

Inadequate hazard identification 9 24

Inadequate hazard evaluation 16 43

Inadequate procedures for storage/handling of 

reactive chemicals 17 46

Inadequate training for storage/handling of reactive 

chemicals 10 27

Inadequate management of change (MOC) system 

to Identify/evaluate reactivity hazards 6 16

Inadequate process design for reactive hazards 6 16

Inadequate design to prevent human error 9 24

Inadequate company-wide communication of 

hazards 5 14

Inadequate emergency relief system design 3 8

Inadequate safe operating limits 3 8

Inadequate near miss/incident investigation 2 5

Inadequate inspection/maintenance/monitoring of 

safety critical devices in reactive chemical service 2 5

Previously unknown reactive hazards 1 3

(a) Causal data are reported for 37 of the 167 incidents.

(b) Total greater than 100 percent because each incident may have more than one cause.
Reactives Hazard Investigation 10-17-02, page 48

4.0 NFPA Hazard Rating System

CSB analyzed incident data in terms of the chemicals published in NFPA Standards 49 and 325. The data 

show that only about 10 percent of the 167 known incidents involved chemicals that were rated NFPA 

“3” or “4” (Figure 15). NFPA “not rated” or “0” accounts for nearly 60 percent of the data.. (Both the 

BPS and the Morton incidents involved chemicals that were not rated by NFPA.) 

Not published in 

NFPA 49 or 325:

36%

NFPA 1:

11%

NFPA 4:

3% NFPA 3:

8%

NFPA 2:

20%

NFPA 0:

21%

Figure 15. NFPA instability rating analysis (formerly reactivity rating) of incident data, 1980–2001.
Reactives Hazard Investigation 10-17-02, page 49

The OSHA PSM Standard lists 137 highly hazardous chemicals–only 38 of which are considered highly 

reactive based on NFPA ratings “3” or “4”34 (as defined in NFPA 704, Standard System for the 

Identification of the Hazards of Materials for Emergency Response). 

Public and labor union concerns as the result of a number of reactive incidents have caused OSHA to 

consider PSM revisions. One alternative OSHA identified through a petition from unions (Section 5.1.3) 

is to add the remaining NFPA “3” and “4” chemic als and all NFPA “1” and “2” chemicals to the PSM 

list. However, this approach would address less than half of the chemicals involved in the 167 incidents 

examined by CSB.

NFPA developed Standard 704 as a tool for identification and evaluation of potentia l hazards during 

emergency response, not for application to chemical process safety. The instability rating is a part of this 

standard. It was not intended to be used to measure reactivity, but rather to measure the “inherent” 

instability of a pure substance or product under conditions expected for product storage. The instability 

rating does not measure the tendency of a substance or compound to react with other substances or any 

other process-specific factors, such as operating temperature, pressure, quantity handled, chemical 

concentration, impurities with catalytic effects, and compatibility with other chemicals onsite. 

NFPA 704 is a voluntary standard. Table 5 lists the five degrees of hazard defined in NFPA 704. The 

NFPA hazard rating system primarily relies on qualitative criteria and judgment to assign chemical

 

34 The PSM chemical list is based on ratings in NFPA 49 (1975). Six of the 137 PSM chemicals are listed twice. 

An NFPA instability rating of “4” means that materials in themselves are readily capable of detonation or explosive 

decomposition or explosive reaction at normal temperatures and pressures (13 of 131 PSM-listed chemicals have an 

NFPA “4” reactivity). A rating of “3” means that materials in themselves are capable of detonation or explosive 

decomposition or explosive reaction, but require a strong initiating source or must be heated under confinement 

before initiation (25 of 131 PSM-listed chemicals have an NFPA “3” reactivity).
Reactives Hazard Investigation 10-17-02, page 50

instability ratings, which may vary considerably from company-to-company. The instability rating 

system was so named in 1996 to clarify its intent; it was formerly known as the reactivity rating system. 

NFPA 49 lists the ratings for 325 chemicals–representing only a very small percentage of the chemicals 

used in industry.35

Table 5

NFPA-Defined Degrees of Instability Hazards

NFPA 

Instability 

No.

Stability Criteria Typically Includes Water Reactivity 

Criteria (a)

Instantaneous 

Power Density 

Criteria (b) 

4 Materials that in 

themselves are readily 

capable of detonation 

or explosive 

decomposition or 

explosive reaction at 

normal temperatures 

and pressures

Materials that are 

sensitive to 

localized thermal or 

mechanical shock at 

normal temperatures 

and pressures

Not applicable Greater than 

1,000 W/mL

3 Materials that in 

themselves are capable 

of detonation or 

explosive 

decomposition or 

explosive reaction, but 

require a strong 

initiating source or 

must be heated under 

confinement before 

initiation

Materials that are 

sensitive to thermal 

or mechanical shock 

at elevated 

temperatures and 

pressures

Materials that react 

explosively with water 

without heat or 

confinement; heat of 

mixing greater than 

600 cal/g

Less than 

1,000 but 

greater than 

100 W/mL

2 Materials that readily 

undergo violent 

chemical change at 

elevated temperatures 

and pressures

Materials that 

exhibit an exotherm 

at temperatures less 

than 200oC and 

materials that 

polymerize 

vigorously and 

evolve heat

Materials that react 

violently with water or 

form potentially 

explosive mixtures 

with water; heat of 

mixing less than 600 

but greater than 100 

cal/g

Less than 100 

but greater 

than 10 W/mL

 

35 The Chemical Abstracts Service maintains data on over 200,000 chemicals that are listed under national and 

international regulations.
Reactives Hazard Investigation 10-17-02, page 51

1 Materials that in 

themselves are 

normally stable, but 

can become unstable at 

elevated temperatures 

and pressures

Materials that 

exhibit an exotherm 

at temperatures 

greater than 200oC 

but less than 500oC

Materials that react 

vigorously with water, 

but not violently; heat 

of mixing less than 

100 but greater than 

30 cal/g

Less than 10 

but greater 

than 0.01 

W/mL

0 Materials that in 

themselves are 

normally stable, even 

under fire conditions

Materials that 

exhibit an exotherm 

at temperatures 

greater than 500oC 

when tested by 

differential scanning 

calorimetry (DSC)

Materials that do not 

react with water; heat 

of mixing less than 30 

cal/g

Less than 0.01 

W/mL

Source: NFPA 704.

(a) cal/g = calories per gram.

(b) W/mL = watts per milliliter.

The more recent editions of NFPA 704 provide some objective criteria (Table 5) for assignment of 

ratings. The degree of instability hazard is ranked based on “ease, rate, and quantity of energy release” of 

the substance (NFPA, 1996). Onset temperature, instantaneous power density (IPD; Hofelich et al., 

1997),36 and–in the case of water-reactive substances–the energy of reaction upon mixing are the 

parameters considered. Onset temperature was added in the 1990 edition of the standard, and the latter 

two criteria were added in 1996. These criteria are not intended to replace the primarily qualitative nature 

of the rating system, but to be used as a hazard recognition aid. Where data are available, NFPA currently 

prefers ratings based on IPD. 

 

36 IPD is calculated as the mathematical product of the energy of decomposition/reaction and the initial rate of 

reaction, determined at 482 degrees Fahrenheit (°F; 250 degrees Celsius [°C]).
Reactives Hazard Investigation 10-17-02, page 52

NFPA 49 is no longer issued in the NFPA Fire Code set, and the standard is no longer updated;37 

however, Standard 704 was updated in 2001. NFPA 49 information is available in the Fire Protection 

Guide to Hazardous Materials (NFPA, 1997). 

NFPA confirmed the intent of NFPA 704 and the instability rating system through correspondence with 

CSB staff. The committee clarified that the rating system is insufficient for use as the sole basis of 

determining reactivity for regulatory lists because it considers only one facet of chemical reactivity. 

NFPA staff reiterated this position in testimony given at the CSB public hearing on reactive chemical 

safety on May 30, 2002. 

 

37 Revision of NFPA 49 was withdrawn as a committee project in 1998.
Reactives Hazard Investigation 10-17-02, page 53

5.0 Regulatory Analysis

5.1 OSHA

5.1.1 Overview 

CSB found significant gaps in OSHA process safety regulations designed to protect workers from highly 

hazardous chemicals, including reactive hazards. OSHA standards cover the hazards of some classes of 

substances, such as flammable and combustible liquids; however, no OSHA standard specifically 

addresses reactive hazards. 

There are OSHA standards designed to protect employees from acute chemical hazards resulting from 

reactive incidents–including fires, explosions, and toxic releases. The Hazard Communication Standard 

(29 CFR 1910.1200) requires chemical manufacturers to evaluate chemicals produced or handled in their 

workplace and to communicate the hazards associated with the products they produce via labels and 

MSDSs. The standard also requires all employers to provide information to employees about the 

hazardous chemicals to which they could be exposed. The PSM Standard (29 CFR 1910.119) requires 

employers to prevent or minimize the consequences of catastrophic releases of highly hazardous 

chemicals, including highly reactive chemicals. 

Numerous other OSHA regulations apply to the chemical industry in general, but are not specific to 

reactive hazards. Where no specific OSHA standards apply, the OSHA General Duty Clause (GDC; 

Section 5(a)(1) of the 1970 Occupational Safety and Health Act) creates a legal obligation for an 

employer to address a known hazard, including a reactive hazard.
Reactives Hazard Investigation 10-17-02, page 54

5.1.2 Process Safety Management 

The CSB incident data were analyzed to determine whether the chemicals involved were considered 

“highly hazardous” under the OSHA PSM Standard. For the purposes of analyzing the data, CSB 

determined if a chemical was covered by OSHA PSM by identifying whether it was listed in PSM or was 

covered as a flammable chemical by OSHA definition.38 

All 167 incidents were included in the analysis, even if the incident predated the promulgation of PSM: 

• In 30 percent of the incidents, the chemicals were covered under PSM. 

• In 50 percent of the incidents, the chemicals were not PSM covered. 

• In 20 percent of the incidents, it could not be determined whether PSM-covered chemicals 

were involved.

CSB was unable to determine from the incident data if a process was PSM covered.39

5.1.2.1 Development of PSM Standard 

Following a series of very serious chemical accidents in the 1980s, OSHA began to develop the PSM 

Standard. The proposed standard was published in 1990, the same year that Congress enacted the Clean 

Air Act Amendments (CAAA). Section 304 of CAAA required OSHA to promulgate a chemical process 

safety standard to protect employees from hazards associated with accidental releases of highly hazardous 

chemicals in the workplace. It further required that OSHA develop and apply the standard to a list of 

 

38 Processes that are covered by the OSHA PSM Standard due to the presence of flammable substances may, in fact, 

have significant reactive hazards as well. An example is a polymerization reaction involving the flammable 

chemical 1,3-butadiene. Such processes are required to address all chemical hazards, including reactive hazards.

39 The CSB analysis is limited by incomplete knowledge of chemical concentrations, quantities, or other covered 

chemicals in the same process–all of which are relevant in determining whether a process is regulated under the 

PSM Standard. 
Reactives Hazard Investigation 10-17-02, page 55

highly hazardous chemicals. Congress specified that highly hazardous chemicals included “toxic, 

flammable, highly reactive, and explosive substances.”

OSHA relied on several established lists–including the New Jersey Toxic Catastrophe Prevention Act 

(TCPA), the Delaware Extremely Hazardous Substances Risk Management Act, the European 

Communities Seveso Directive (82/501/EEC), and NFPA Hazardous Chemicals Data (NFPA 49)–to 

develop its list of highly hazardous chemicals. OSHA chose to list the chemicals classified as reactive 

category “3” or “4” in NFPA 49 (1975 edition).

The OSHA PSM Standard lists 131 distinct chemicals with toxic or reactive properties.40 It includes 25 

chemicals with an NFPA rating of “3” and 13 chemicals with an NFPA rating of “4.” PSM applies to 

processes that involve listed chemicals at or above threshold quantities and to processes with flammable 

liquids or gases onsite in one location, in quantities of 10,000 pounds or more. Companies that 

manufacture explosives and pyrotechnics are also required to comply with the standard. 

The OSHA list has not been updated since the promulgation of PSM in 1992. It does not reflect changes 

in the list of chemicals and their ratings made by NFPA in 1991 and 1994. 

5.1.2.2 Process Safety Information and Process Hazard Analysis

The PSM Standard is a performance-oriented standard that requires the employer to prevent catastrophic 

releases from covered processes by executing a 14-element safety program. All processes with highly 

hazardous chemicals are required to have a management system that addresses each element of the 

standard. 

As supported by the CSB incident data, two elements are particularly relevant to reactive hazards–Process 

Safety Information (PSI; 29 CFR 1910.119 [d]) and Process Hazard Analysis (PHA; 29 CFR 1910.119 

 

40 Six of the 137 chemicals on the PSM list are not distinct (i.e., are listed under a synonym).
Reactives Hazard Investigation 10-17-02, page 56

[e]). Two commonly cited causes of reactive incidents, as shown by the data, are inadequate 

understanding of reactive chemistry or inadequate hazard evaluation (Section 3.0; Table 4). 

The PSM Standard requires that the following information be contained within the PSI element–physical 

data, reactivity data, corrosivity data, thermal and chemical stability data, and hazardous effects of 

potential inadvertent mixing of different materials. The standard does not specifically define what is to be 

included in any of these data categories, the level of detail required, or the method of compilation.41 It 

does, however, stipulate that an MSDS can be used to compile the data to the extent that it contains the 

information required. In 1996, OSHA issued a Hazard Information Bulletin cautioning that MSDSs do 

not always contain information about hazards from mixing or blending chemicals (OSHA, 1996). 

Another requirement of the PSM Standard is that the employer conduct process hazard analysis, which 

OSHA defines as “an organized and systematic effort to identify and analyze the significance of potential 

hazards associated with the processing or handling of highly hazardous chemicals.” The analysis must 

identify the hazards of the process and necessary safeguards; however, the standard does not explicitly 

define requirements for addressing reactive hazards.

It is evident that the PSM Standard has significant gaps in coverage of reactive hazards because it is based 

on a limited list of individual chemicals with inherently reactive properties.

 

41 Incident data in Section 3.0 illustrate that reactive hazards are broader than the “hazardous effects of potential 

inadvertent mixing of different materials.”
Reactives Hazard Investigation 10-17-02, page 57

5.1.3 General Duty Clause

The OSHA GDC states, “Each employer shall furnish to each of his [sic] employees employment and a 

place of employment which are free from recognized hazards that are causing or are likely to cause death 

or serious physical harm to his [sic] employees.” In the event that there is no OSHA standard to address a 

hazard, OSHA may use the GDC to enforce a legally binding requirement on an employer or impose a 

fine. To substantiate a GDC violation, several criteria must be met,42 including: 

• A condition or activity in the employer’s workplace presents a hazard to employees. 

• The cited employee or the employer’s industry recognizes the hazard. 

• The hazard is likely to cause death or serious physical harm. 

• There is a feasible means of eliminating or materially reducing the hazard.

To support a GDC citation, OSHA must establish employer or industry recognition of a hazard. Among 

other forms of evidence, industry recognition may be demonstrated by a consensus standard (NFPA, 

American National Standards Institute [ANSI], American Petroleum Institute [API], American Society 

for Testing and Materials [ASTM], etc.). Industry standards may also be used to identify feasible means 

of reducing the hazard. However, no industry consensus standard has been identified for the management 

of reactive hazards in support of a GDC citation.43

5.1.4 Other PSM Initiatives

As a result of the joint OSHA-EPA chemical accident investigation of the Napp Technologies incident in 

April 1995, a recommendation was made by both agencies to consider adding more reactive chemicals to 

 

42 OSHA response to CSB interrogatory for the reactive chemical hazard investigation, June 6, 2001.

43 OSHA response to CSB interrogatory for the reactive chemical hazard investigation, June 6, 2001.
Reactives Hazard Investigation 10-17-02, page 58

their respective lists of chemicals covered by process safety regulations. To date, however, neither OSHA 

nor EPA has modified process safety regulations to better cover reactive hazards.

Following the Napp incident, six labor unions44 petitioned OSHA for emergency revision of the PSM 

Standard, stating that it failed to cover reactive chemicals. In a followup letter, the labor unions asked 

OSHA to consider the following issues in any revision of the standard:

• Addition of NFPA category “1” and “2” reactives to the list of highly hazardous chemicals.

• Hazard evaluation, including the conditions for use of highly hazardous chemicals. 

• Adequacy of the NFPA ratings process. 

• Synchronization of the OSHA PSM and the EPA RMP lists; and expansion of worker/union 

involvement.

In February 1996, the Chemical Manufacturers Association (now ACC) and API submitted a letter to 

OSHA responding to issues raised by the labor unions. The letter indicated ACC support of PSM as an 

effective standard. It also reflected the opinion that expanding PSM in the ways proposed would greatly 

increase compliance costs without substantial benefits and that a large amount of the additional cost 

would fall on small businesses. ACC and API identified several alternatives for regulating reactives, but 

concluded that each presented technical difficulties, significant cost, and minimal benefit. For these 

reasons, both trade groups opposed any revisions to the PSM Standard. 

 

44 Union of Needletrades, Industrial, and Textile Employees (UNITE); United Steelworkers of America (USWA); 

Oil, Chemical, and Atomic Workers (OCAW); American Federation of Labor-Congress of Industrial Organizations 

(AFL-CIO); International Association of Fire Fighters (IAFF); and International Chemical Workers Union (ICWU). 

In 1999, OCAW merged with the United Paperworkers International Union to form the Paper, Allied-Industrial, 

Chemical & Energy Workers International Union (PACE). In 1996, ICWU merged with the United Food and 

Commercial Workers International Union (UFCW).
Reactives Hazard Investigation 10-17-02, page 59

OSHA did not undertake an emergency revision of the PSM Standard in response to the labor unions’ 

petition. In October 1997, OSHA and EPA issued a joint chemical accident investigation report on the 

Napp Technologies incident. Among the recommendations was that OSHA and EPA review the lists of 

substances subject to the PSM Standard and RMP regulation (40 CFR 68) to determine whether reactive 

substances should be added.

The OSHA regulatory agenda published on May 14, 2001, indicated that it intended to reconsider the 

reactives issue that year. However, in the regulatory agenda published on December 3, 2001, OSHA 

withdrew from consideration changes to the PSM Standard. A May 21, 2002, letter from John Henshaw, 

Assistant Secretary of Labor for OSHA, to CSB stated that issues related to reactives–though dropped 

from the current regulatory agenda–would be reconsidered and possibly raised in future regulatory 

agendas. 

5.2 EPA

5.2.1 Overview 

Similar to OSHA, EPA has no regulations specifically targeted to reactive hazard management. 

However, some legal requirements cover limited aspects of reactivity. The EPA RMP and GDC are two 

such requirements, as discussed in more detail below. EPA has made no decision on how to address 

reactivity because it has not yet identified a technically sound method for determining reactive 

substances.45

CSB incident data were analyzed with respect to coverage under the EPA RMP regulation: 

• In 20 percent of the incidents, the chemicals were covered under RMP.

 

45 EPA response to CSB interrogatory for the reactive chemical hazard investigation, May 31, 2001.
Reactives Hazard Investigation 10-17-02, page 60

• In 60 percent of the incidents, the chemicals were not RMP listed.

• In 20 percent of the incidents, it could not be determined whether RMP-listed chemicals were 

involved.

The 1990 CAAA required EPA to promulgate regulations to prevent the accidental release of substances 

that could cause death, injury, or serious adverse effects to human health or the environment. Congress 

directed EPA to regulate at least 100 substances and to take into account several factors when developing 

a chemical list, including “toxicity, reactivity, volatility, dispersibility, combustibility, or flammability of 

the substance, and amount of the substance.”

5.2.2 Accidental Release Prevention Requirements (40 CFR 68)

EPA promulgated the Accidental Release Prevention Requirements (40 CFR 68), which contain the list of 

regulated chemicals and requirements for facilities possessing more than a threshold quantity of a listed 

chemical in an individual process. Covered facilities are required to implement a risk management 

program and submit a risk management plan to EPA. 

When developing the list of substances, EPA considered only the inherent characteristics of a chemical 

that indicate a severe threat due to exposure. Well-defined criteria were used for toxicity and 

flammability. However, because of the complexities of site-specific factors and process conditions, EPA 

was unable to determine any inherent characteristic as an indicator of reactivity. EPA concluded that 

there was “insufficient technical information for developing criteria for identifying reactive substances.”46 

Consequently, the January 1994 RMP list of 130 chemicals does not contain any substances listed due to 

reactive hazards. 

 

46 EPA Response to CSB interrogatory for the reactive chemical hazard investigation, May 31, 2001.
Reactives Hazard Investigation 10-17-02, page 61

Unlike OSHA’s use of criteria for covering classes of chemicals, such as the criterion for flammable 

substances as a class, EPA has used only chemical lists for the RMP regulation. The authority provided 

by Congress in the CAAA for EPA to develop the Accidental Release Prevention Requirements is explicit 

on the use of a “List of Substances” (Section 112[r][3]) to identify the covered chemicals. 

The list of RMP-regulated chemicals has not been revised since the October 1997 recommendation by the 

OSHA-EPA joint chemical accident investigation team to review the lists of substances subject to the 

PSM Standard and RMP regulation to determine whether reactive chemicals should be added.

RMP requires covered processes to have a hazard assessment, a prevention program, and an emergency 

response program. The hazard assessment must evaluate the accidental release of regulated substances, 

including the worst case scenario. RMP contains requirements for prevention of accidental releases, 

which include the same basic elements as the OSHA PSM Standard. Therefore, the limitations described 

in Section 5.1.2.2 with respect to process safety information and process hazard analysis also apply to 

RMP.

It is evident that the EPA RMP has significant gaps in coverage of reactive hazards.

5.2.3 General Duty Clause

The EPA GDC is a statutory requirement found in Section 112(r)(1) of the 1990 CAAA. It reads as 

follows:

The owners and operators of stationary sources producing, processing, handling or storing [a 

chemical in 40 CFR 68 or any other EHS] have a general duty [in the same manner and to the 

same extent as the OSHA GDC] to identify hazards which may result from such releases using 

appropriate hazard assessment techniques, to design and maintain a safe facility taking such steps 

as are necessary to prevent releases, and to minimize the consequences of accidental releases 
Reactives Hazard Investigation 10-17-02, page 62

which do occur.

GDC applies to all stationary sources (fixed facilities) that handle, produce, process, or store regulated 

substances or extremely hazardous substances (EHS)47. It obligates facilities to identify and safely 

manage all hazards, including reactive hazards. Similar to OSHA, EPA can use its GDC enforcement 

authority to create legally binding requirements or enforce actions for hazards that have not been properly 

identified or managed. 

The EPA GDC is not limited solely to hazards addressed by industry standards; however, there are no 

standards for management of reactive hazards that can be used to enforce a general duty on industry.

The EPA GDC enforcement authority can be used in either a proactive (before an incident) or a reactive 

(after an incident) manner. EPA can use its order authority (CAA Section 112[r][9]) to enforce GDC in a 

case where it finds the possibility of imminent and substantial endangerment. EPA has used GDC order 

authority in only one situation for reactive hazards. 

 

47 The Senate Report on the 1990 CAAA stated that EHS includes substances specifically listed under EPA’s 

Accidental Release Prevention Requirements (40 CFR 68) and substances listed under Section 302 of the 

Emergency Planning and Community Right-to-Know Act (EPCRA). The definition also includes substances not 

necessarily listed that–due to their toxicity, reactivity, flammability, volatility, or corrosivity–may cause death, 

injury, or property damage as a result of short-term exposure upon release to the air. 
Reactives Hazard Investigation 10-17-02, page 63

6.0 Management System Guidance 

Inadequate process safety management practices are often cited as the cause of reactive incidents, as 

discussed in Section 3.0 (Table 4). Incident data underscore the critical importance of successfully 

implementing the following key elements throughout the life cycle 48 of a manufacturing process: 

• Hazard identification–structured approach to identifying and understanding the reactive 

hazards of chemicals used alone or in combination.

• Hazard evaluation–system for investigating reactive hazards, assessing the potential 

consequences of uncontrolled reactions, and establishing a safe design and operating basis. 

• Management of change (MOC)–procedure to re-evaluate reactive hazards when changes 

occur throughout the life cycle of a chemical process. 

• Personnel training and procedures–program that includes written operating procedures and 

consideration of the potential for human error in reactive systems.

CSB staff found a considerable amount of technical guidance for chemists and process engineers on how 

to identify reactive hazards during the R&D and design phases. This guidance covers chemical 

manufacturing processes and storage/handling situations.

 

48 “ Life cycle” refers to all phases of a chemical manufacturing process–from conceptualization, process R&D, 

engineering design, construction, commissioning, commercial operation, and major modification to 

decommissioning.
Reactives Hazard Investigation 10-17-02, page 64

However, only limited guidance is available on the following aspects of reactive hazards management:

• Use of reactive test data, including data from the reactive hazard evaluation.

• Use of a protocol to identify reactive hazards (e.g., checklist or specific guidewords).

• Application of a chemical interaction matrix.

• Identification and evaluation of worst case scenarios involving uncontrolled reactivity.

• Integration of reactive hazard information into process safety information, operating 

procedures, training, and communication practices. 

• Evaluation of reactive hazards during MOC procedures. 

Companies engaged primarily in the bulk storage, handling, and use of chemicals are particularly in need 

of concise guidance on preventing the inadvertent mixing of incompatible substances. 

Additionally, as discussed earlier, though several computerized tools and literature resources are available 

to identify reactive hazards, the surveyed companies generally do not use them. Also, they typically do 

not share detailed reactive chemical test data. 

6.1 Hazard Identification

Understanding and identifying reactive hazards is a key component of process knowledge. It is often the 

first activity in managing reactive hazards and may occur early in product research or in process 

development. Ineffective hazard identification is commonly cited as a cause of reactive incidents. Where 
Reactives Hazard Investigation 10-17-02, page 65

some causal information is available from CSB’s data search,49 about 25 percent of incidents are 

attributed to this factor. 

The identification of reactive hazards is a prerequisite to conducting a hazard evaluation and developing 

safe design, operation, and maintenance practices (CCPS, 1992; pp. 9, 12). A variety of reactive hazard 

identification methods are currently used, including literature searches and screening tests (CCPS, 1995a, 

1995b; HSE, 2000; Barton and Rogers, 1997). No one technique is appropriate for all circumstances. 

6.1.1 Existing Sources of Data

Relevant sources of information for reactive hazard data include the following, as noted throughout this 

report and listed in Section 11.0:

• Bretherick’s Handbook of Reactive Chemical Hazards. 

• U.S. Coast Guard (USCG) Chemical Hazard Response Information System (CHRIS) 

Database. 

• NFPA 49, Hazardous Chemicals Data. 

• NFPA Fire Protection Guide to Hazardous Materials.

• Sax’s Dangerous Properties of Industrial Materials.

• National Oceanic and Atmospheric Administration (NOAA) The Chemical Reactivity 

Worksheet. 

 

49 Causal information is available in approximately 20 percent of the incidents identified by CSB.
Reactives Hazard Investigation 10-17-02, page 66

• Rapid Guide to Chemical Incompatibilities.

• ASTM Chemical Thermodynamic and Energy Release Program (CHETAH).

Responses to the CSB industry survey50 indicate that most companies consult a variety of information 

sources as a first step in compiling data on reactive hazards. However, respondents prefer literature 

sources and expert opinion over computerized tools such as CHETAH, The Chemical Reactivity 

Worksheet, or Bretherick’s Database of Reactive Chemical Hazards. Such programs can be used to 

predict the thermal stability of compounds, reaction mixtures, or potential chemical incompatibilities. In 

some cases, they provide an efficient means of identifying reactive hazards without having to conduct 

chemical testing. Survey responses showed that five of nine companies consider computer-based tools 

“not valuable.” Only two of the surveyed companies use The Chemical Reactivity Worksheet.51 

CSB data show that hazard information was available in existing literature for over 90 percent of the 

reactive incidents. 

6.1.2 Chemical Incompatibility

Approximately 36 percent of incidents in the CSB data are related to chemical incompatibility. CCPS 

provides information on managing chemical incompatibility hazards in guidelines for chemical reactivity. 

It emphasizes the need to systematically examine possible chemical incompatibilities and describes the 

use of interaction matrices (CCPS, 1995a, p. 7; 1995b, p. 108). 52,, 

53 This guidance applies to chemical 

manufacturers as well as to other industries. 

 

50 Appendix B describes the CSB industry survey. 

51 The survey did not seek to determine whether the participants had used the tools and concluded that they were of 

little value, or whether they had only a limited understanding of the potential benefits.

52 An interaction matrix indicates whether the combination of two or more materials yields an undesired 

consequence (see ASTM E2012-99, Standard Guide for Preparation of Binary Chemical Compatibility Chart).

53 Section 6.1.1 lists data sources for developing an interaction matrix.
Reactives Hazard Investigation 10-17-02, page 67

In many cases, it is not possible to identify hazards through intrinsic chemical properties because they 

may be caused by the interaction of process chemicals, either inadvertent or intentional. Such hazards are 

commonly encountered at facilities primarily engaged in the bulk storage, handling, and use of chemicals. 

There is limited guidance on segregation and isolation of incompatible substances, handling water- or airreactive chemicals, training, and MOC.

Seven of nine respondents use chemical interaction matrices to identify potential chemical 

incompatibilities. Most use a binary matrix (i.e., the mixing of only two chemical components at a time). 

Respondents indicated that literature or expert opinion are important sources of data for the matrix. 

Five of the seven respondents who use a matrix also use chemical testing results as a data source. A 

similar number review the matrix during qualitative hazard evaluation studies (i.e., hazard and operability 

[HAZOP] studies, “what-if,” checklist, etc.). 

CCPS (1995a; pp. 46-49) provides only limited discussion on when to conduct an incompatibility study 

or how to apply the results during a hazard evaluation. It suggests that the PHA team review the 

interaction matrix, but does not provide detailed guidance on this subject (CCPS, 1995b; p. 111). 

6.1.3 Thermal Hazards

From the data collected by CSB, 35 percent of the 167 incidents are attributed to runaway reaction 

hazards. CCPS (1995a, Ch. 2; 1995b, Ch. 3), HSE (2000; pp. 15-28), and IChemE (Barton and Rogers, 

1997; pp. 20-45) offer guidance on methods for identifying thermal hazards such as runaway reactions. 

In Guidelines for Safe Storage and Handling of Reactive Materials, CCPS (1995b; p. 58) outlines a 

materials assessment strategy for hazard identification that applies various recognition aids along with 

expert judgment and experience. The guidelines suggest evaluation of each substance stored or handled 

onsite. 
Reactives Hazard Investigation 10-17-02, page 68

6.1.4 Chemical Reactivity Testing

When there are gaps in literature or expert knowledge of reactive hazards, industry good practice 

guidelines (e.g., CCPS, 1995a; p. 13) recommend chemical testing prior to scaleup of a chemical 

manufacturing process. Chemical reactivity testing can be used either to aid in hazard identification 

during product research or to evaluate hazards during capital projects. Most survey participants view 

chemical testing as a valuable part of the hazard identification process. Appendix G presents more 

detailed information on testing. 

The survey participants were asked about their reactivity testing programs. Three of five companies 

visited by CSB use expert opinion to examine the need for testing. Seven of nine use a mix of in-house 

and contracted testing capabilities. Two respondents rely on literature surveys and expert opinion instead 

of chemical testing. Only two of 10 respondents to a recent SOCMA survey54 use reactive chemical test 

data to identify hazards. (SOCMA membership includes many small- and medium-sized companies.) 

Guidance on when to conduct testing is not consistent. When designing processes for conducting 

chemical reactions, CCPS (1995a; p. 13) suggests that all materials be subject to screening tests, even if 

no reactivity concerns are identified in the literature search and expert judgment. In other guidance, 

CCPS (1995b; p. 85) states that in designing storage and handling systems for reactive materials, prior 

experience, theoretical evaluations, and expert opinion may be used to determine the need for screening 

tests. 

 

54 SOCMA conducted a survey of reactive hazard management practices among its 300 member companies during 

the April 2001 Responsible Care conference. The survey consisted of a two-page questionnaire distributed at a 

working session on reactive chemical safety. Ten companies responded. A copy of the survey report was provided 

to CSB.
Reactives Hazard Investigation 10-17-02, page 69

6.1.5 Accessibility of Chemical Reactivity Test Data

Although no dedicated data repository for reactive chemical test results is generally available to industry 

or the public, a substantial amount of test data have been generated by the chemical industry. One 

company visited by CSB had compiled a database of over 60,000 reactive chemical test results. Survey 

participants were asked if such data are shared with other companies. 

CSB investigators determined that the surveyed companies share data of a general nature for most 

chemicals (i.e., data typically found on an MSDS) and good handling practices for some. This typically 

does not include reactive chemical test data. Several reasons were given for the absence of substantial 

data sharing, including:

• Potential liability concerns 

• Need for expert interpretation of reactivity data

• Reluctance to share trade secrets or confidential business information.

Currently, there is no mechanism to effectively share reactive chemical test data throughout industry. The 

feasibility of a publicly available test database has not yet been studied by industry or government. 

Reactive chemical experts at one company visited by CSB expressed an interest in working with the 

National Institute of Standards and Technology (NIST) to develop such a database. 

6.2 Hazard Evaluation

More than 40 percent of the 167 incidents from the CSB data search, where some causal information is 

available,55 are attributed to inadequate hazard evaluation. In several cases, the hazard was known, but its 

 

55 Causal information is available in approximately 20 percent of the incidents identified by CSB.
Reactives Hazard Investigation 10-17-02, page 70

potential magnitude was not–nor was the potential severity of the consequence. In other cases, the hazard 

evaluation did not properly identify initiating events. 

IChemE acknowledges that “there is no standard procedure for evaluating chemical reaction hazards” 

(Barton and Rogers, 1997; p. 120). The CSB survey further highlights the variety of approaches to 

reactive hazard evaluation; companies rely to varying degrees on quantitative and qualitative evaluation 

methods.

6.2.1 Quantitative Methods 

A prerequisite to any process hazard evaluation is adequate knowledge of the chemistry. Prior to 

specifying safe design and operating requirements, identified hazards must be evaluated to understand 

what can go wrong and the potential consequences. CCPS (1995a, p. 17; 1995b, p. 94) and IChemE 

(Barton and Rogers, 1997; p. 28) provide guidance on parameters for reactive hazard evaluation. 

Quantitative modeling techniques and calorimetry data are sometimes required along with extensive 

process-specific information.56 

Both HSE (2000; p. 34) and IChemE (Barton and Rogers, 1997; p. 107) emphasize the need to identify a 

worst case scenario involving uncontrolled reaction to ensure that safety systems are designed and 

maintained to provide adequate protection under all postulated circumstances. When identifying the 

worst case, IChemE provides a general recommendation to evaluate any scenario not protected by high 

 

56 Good practice guidelines illustrate how these parameters are typically examined for both normal and postulated 

abnormal conditions, such as variations in reactant quantity, concentration, agitation, sequence, time, failure of 

utilities, and instrumentation. Qualitative hazard evaluation protocols are not well suited for such complex chemical 

phenomena (e.g., the severity of an uncontrolled reaction under a loss of electrical power may not be apparent 

without sufficient test data).
Reactives Hazard Investigation 10-17-02, page 71

integrity shutdown systems.57 However, there is little guidance on how to systematically identify and 

evaluate a worst case scenario involving uncontrolled reaction.

6.2.2 Qualitative Methods 

Chemical reactivity information is gathered from data searches, calculations, and reactivity testing. 

Qualitative hazard evaluation is one commonly used approach to assessing process hazards, including 

reactive hazards (CCPS, 1992). 

Several qualitative approaches can be used to identify hazardous reaction scenarios, including process 

hazard analysis, checklists, chemical interaction matrices, and an experience-based review. CCPS 

(1995a; p. 176) describes nine hazard evaluation procedures that can be used to identify hazardous 

reaction scenarios–checklists, Dow fire and explosion indices, preliminary hazard analysis, “what-if” 

analysis, failure modes and effects analysis (FMEA), HAZOP study, fault tree analysis, human error 

analysis, and quantitative risk analysis. 

Although each of these methods can be useful in identifying reactive scenarios, none are designed 

specifically to address the reactive hazard. Existing good practice guidelines from CCPS (1992), HSE 

(2000), and IChemE (Barton and Rogers, 1997) do not adequately address how to manage the unique 

aspects of reactive hazards while performing hazard evaluations.

The CSB survey identified examples of modified or hybrid techniques to identify reactive hazard 

scenarios and ensure the implementation of adequate safeguards. For example, companies conducting 

reactions in batch chemical reactors often conduct HAZOP studies by evaluating deviations from

 

57 Instrumentation, Systems, and Automation Society (ISA) Standard 84, Application of Safety Instrumented 

Systems for the Process Industries, outlines the principles of high integrity shutdown systems.
Reactives Hazard Investigation 10-17-02, page 72

 procedural steps as opposed to deviations from intended equipment design. One company uses a “whatif” PHA protocol specifically designed to address reactivity hazards. 

Most survey respondents indicated that they perform reactive hazard evaluation studies during specific 

life-cycle phases of a process or product. These phases include process development, commercial process 

design, periodic re-evaluation, and before proposed modifications. The protocol for hazard evaluation of 

reactive systems varies from company-to-company. At a minimum, all surveyed companies employ 

qualitative hazard evaluations.58 

Industry guidance from CCPS (1995a; 1995b), HSE (2000), and IChemE (Barton and Rogers, 1997) 

contains little information on how and when to apply reactive chemical test data during a process hazard 

analysis. During site visits, CSB investigators encountered PHA teams that use test data to evaluate 

reactive hazards. In combination with input on reactive chemistry, the test data are used to assist in 

evaluating appropriate safe operating limits and potential consequences of an uncontrolled reaction. 

This practice supports the CSB observation that effective process hazard analysis for a reactive system is 

essentially more “data driven” than conventional process hazard analysis given the technical complexity 

of the reactive hazard. Three of the five visited companies use reactivity test data when conducting 

process hazard analysis; two use qualitative hazard evaluation methods only.

6.3 Management of Change

MOC is a systematic procedure for reviewing potential hazards of proposed changes to facilities. It 

applies to all hazardous materials regardless of reactivity; however, there are specific considerations for 

 

58 Qualitative hazard evaluation is commonly referred to as “process hazards analysis,” or PHA, which is used in 

OSHA PSM.
Reactives Hazard Investigation 10-17-02, page 73

reactive hazards. Inadequate MOC procedures are a contributing cause of several reactive incidents 

described in Section 3.0. 

For reactive processes, MOC applies to increases or decreases in process temperature, changes in raw 

material specifications, concentration changes, process time changes, and changes in materials of 

construction (HSE, 2000; p. 41). CCPS (1995a, p. 6; 1995b, p. 197) explains that chemical testing may 

be required to identify and evaluate new hazards from process changes.

Overall, there is a lack of specific guidance on how to evaluate reactive hazards during the MOC 

procedure. Existing guidelines from CCPS (1995a; 1995b), IChemE (Barton and Rogers, 1997), and 

HSE (2000) do not address how to maintain and update reactive hazard evaluation as part of the change 

approval procedure–nor do they address what type of change to process chemistry or product formulation 

necessitates a review and possible update of the reactive hazard evaluation.

6.4 Personnel Training and Procedures

Personnel training and performance–as a management systems element–focuses on development of 

process knowledge and documentation, including clearly defined technical information and operating 

procedures (CCPS, 1989). 

Incident data in Section 3.0 show that more than half of the reactive incidents, where some causal 

information is available, are attributed to inadequate operating procedures and training. These data 

illustrate the challenge of effectively communicating a practical, working knowledge of an often complex 

array of chemical and process information.

Personnel who work with reactive chemicals must understand the hazards they face and take precautions 

to ensure safety (HSE, 2000; p. 42). Training is required for both technical personnel (e.g., process 
Reactives Hazard Investigation 10-17-02, page 74

engineers, chemists) and operators and maintenance personnel. In the Morton case, plant personnel did 

not have a proper understanding of reactive hazards and were unaware of the potential for a runaway 

reaction. The Morton case and others described in Section 3.0 show that reactive hazard management 

requires a working knowledge of the complex intersection of chemical properties and process-specific 

conditions. 

Both IChemE (Barton and Rogers, 1997; p. 137) and HSE (2000; p. 42) briefly address operator training 

in systems that involve reactive hazards. None of the guidelines, however, address the transfer and 

communication of this information to technical personnel. There is little guidance on integrating reactive 

hazard information into operating procedures, training, and communication practices.

At one company visited by CSB, newly appointed production managers are required to demonstrate their 

knowledge of reactive hazards before a review committee. The basis for technical and managerial 

training is an established “operating discipline,” an up-to-date reference of process knowledge containing 

technical details, operational details, and process hazard information. This approach to ensuring technical 

and management personnel training is unique among survey participants. 

6.5 Summary

Guidance on safety management throughout the life cycle of a process is limited. CCPS (1989; 1994) 

provides a framework for a systems-based approach to managing chemical process safety. No 

organization provides comprehensive guidance on technical and management practices for reactive 

hazards that applies to all phases of the process life cycle, though CCPS (1995b; pp. 193-202) briefly 

describes how these management principles apply to reactive hazards. 

Good management practices include not only hazard identification and evaluation early in R&D, but also 

issues such as MOC throughout the life of the chemical manufacturing process. The existing body of 
Reactives Hazard Investigation 10-17-02, page 75

knowledge is largely focused on technical topics, such as calorimetry testing, engineering design, scaleup, 

and emergency venting. CCPS currently has a project underway that addresses technical and 

management practices for reactive hazards. 
Reactives Hazard Investigation 10-17-02, page 76

7.0 Industry Initiatives

Voluntary industry initiatives supplement regulatory requirements. The chemical industry has voluntarily 

undertaken several initiatives to provide guidance on chemical process safety, including processes 

involving reactive hazards. However, at present, no industry initiatives list specific codes or requirements 

for reactive hazard management. 

7.1 Responsible Care Process Safety Code

Approximately 70 percent of incidents in CSB data occurred in the chemical manufacturing industry. 

Both ACC and SOCMA have programs to promote good practices among their member companies in the 

area of chemical process safety.59 In 1989, ACC developed the Responsible Care Process Safety Code60

to prevent fires, explosions, and accidental chemical releases. The code and its accompanying resource 

guidelines include a series of recommended management practices. 

Responsible Care is intended to apply throughout the life cycle of a process–from conception and design 

through construction and startup, and continuing with long-term operation of the facility. The safety 

practices are divided into four areas, as listed in Table 6. Although many practices are similar to 

requirements of the OSHA PSM Standard, the Responsible Care Process Safety Code includes such 

additional elements as accountability, multiple safeguards, and performance measurement. The ACC and 

SOCMA bylaws obligate member companies to participate in Responsible Care, which includes making 

good faith efforts to implement the program elements. Companies are required to undergo a selfevaluation process; a third-party management systems verification (MSV) audit is optional. 

 

59 Currently, ACC has approximately 190 member and partner companies, representing 1,700 facilities. SOCMA–

with 300 member companies, representing 2,000 facilities–has been a Responsible Care Partner Association since 

1990. 

60 Approximately 30 chemical industry associations are Responsible Care Partner Associations.
Reactives Hazard Investigation 10-17-02, page 77

Table 6

ACC Responsible Care Safety Management Practices 

Management Leadership in Process Safety

 1 – Commitment

 2 – Accountability

 3 – Performance Measurement

 4 – Incident Investigation

 5 – Information Sharing

 6 – Community Awareness and Emergency Response (CAER) Integration

Process Safety Management of Technology

 7 – Design Documentation

 8 – Process Hazards Information

 9 – Process Hazard Analysis 

10 – Management of Change

Process Safety Management of Facilities

11 – Siting 

12 – Codes and Standards

13 – Safety Reviews

14 – Maintenance and Inspection

15 – Multiple Safeguards

16 – Emergency Management

Managing Personnel for Process Safety

17 – Job Skills

18 – Safe Work Practices

19 – Initial Training

20 – Employee Proficiency 

21 – Fitness for Duty

22 – Contractors
Reactives Hazard Investigation 10-17-02, page 78

7.1.1 Guidance on Implementation

ACC has published a resource guide to aid member companies in implementing the Responsible Care 

Process Safety Code (ACC, 1989). Although the guide provides suggestions on how to continually 

improve process safety, it does not prescribe how to comply with the code. It does not list specific 

requirements for reactive hazard management, but does require management systems to be developed–

several of which could apply to reactive hazards as determined by each member company. 

Currently, ACC highlights reactive hazard management only in the following areas: 

• Management Practice 7, Design Documentation, which emphasizes the need to develop and 

retain process description, chemistry, and “reaction data.”

• Management Practice 8, Process Hazards Information, which describes the need to maintain 

current, accessible information on material characteristics, including “reactivity.” 

Management Practice 12, Codes and Standards, discusses the need to identify, use, and comply with 

voluntary and consensus standards where applicable. 

ACC member companies are required to establish company-specific goals against which progress is 

measured toward the common vision of no accidents, injuries, or harm to the environment. An example 

of one such goal is to limit the annual number of process safety incidents below a target level. 

Member companies submit to ACC annual reports on process safety incidents that meet specific criteria.61 

The ACC Process Safety Code Measurement System (PSCMS), established in 1996, contains data on 

 

61 The criteria include any fire or explosion causing more than $25,000 in property damage; an episodic loss of 

containment incident of a chemical in excess of the threshold quantities listed in 40 CFR 355.40, Appendix A; an 

episodic loss of containment incident involving more than 5,000 pounds of a flammable substance; or any fire, 

explosion, or chemical release that involves one or more fatalities or serious injuries.
Reactives Hazard Investigation 10-17-02, page 79

type of incident (i.e., fire, explosion, toxic gas), number of injuries, etc., for 1,500 facilities–but no data 

on causes of incidents or lessons learned. 

PSCMS is primarily designed as a metric for tracking industry performance on process safety incidents; it 

is not intended to be a lessons-learned database. However, if expanded to include causes and lessons 

learned and if more widely distributed, the data could be useful in preventing similar incidents. 

7.1.2 SOCMA Guidance on Implementation

The Guide to Process Safety is designed to help with implementation of the Responsible Care Process 

Safety Code (SOCMA, 1999). The guide presents voluntary, proactive initiatives for the continuous 

improvement of process safety performance. 

The SOCMA process safety committee informally shares information on incidents at member facilities, 

but it does not offer a formal incident reporting mechanism such as the ACC PSCMS. 

7.2 NACD Responsible Distribution Process

Reactive incidents are not unique to the chemical manufacturing industry. Approximately 30 percent of 

incidents in CSB data occurred at industria l facilities that use or consume chemicals in bulk quantities.

NACD is an association of chemical distributor companies that purchase and take title of chemical 

products from manufacturers.62 Member companies process, formulate, blend, repackage, warehouse, 

transport, and market chemical products to industrial customers. NACD has developed the Responsible 

Distribution Process(RDP), which is similar in concept to the ACC Responsible Care code.

 

62 NACD has approximately 300 member companies and distributes to 750,000 industrial customers. 
Reactives Hazard Investigation 10-17-02, page 80

As a condition of NACD membership, each chemical distribution company is required have an active 

safety management program designed to continuously improve safety and reduce incidents. The RDP 

code has been in place since 1991 and includes risk management, compliance review and training, carrier 

selection, handling and storage, job procedures and training, waste management, emergency response and 

public preparedness, community outreach, and product stewardship.

NACD (1997) has published an RDP implementation guide to assist member companies in developing 

programs. A self-evaluation and a third-party onsite MSV audit are required. In the last 3 years, NACD 

has expelled 20 companies because of noncompliance. 

RDP does not contain explicit requirements for reactive hazard management, though several elements 

may apply. For example, the handling and storage element requires; 

. . . procedures for loading and unloading chemicals at the member company’s facilities that result 

in protection of personnel, a reduction in emissions to the environment, and ensures that 

chemicals are loaded and unloaded into and out of proper storage facilities. 

This element implicitly applies to reactive hazards in terms of inadvertent mixing of incompatible 

materials. 

The RDP handling and storage element also requires “a program for providing manufacturer guidance and 

information to customers, warehouses, terminals and carriers on procedures for loading, unloading, and 

storing chemicals.” Again, this element implicitly applies to the communication of good practices for 

reactive hazards–from the manufacturer to the end use customer. The product stewardship element of 

RDP includes similar requirements. 
Reactives Hazard Investigation 10-17-02, page 81

8.0 Alternatives for Improving Regulatory Coverage

There is considerable debate over the need to extend regulatory coverage of reactive hazards. Testimony 

provided at the CSB public hearing on May 30, 2002, and elsewhere indicates a general consensus that 

there are concerns with the number and range (i.e., addressing reactive mixtures of substances as well as 

single substances) of reactive hazards covered under the OSHA PSM Standard and EPA RMP regulation. 

However, there is no consensus on how the problems should be addressed–for example, by regulatory 

means, by voluntary efforts such as ACC’s Responsible Care program, or by a combination of 

approaches. 

There are significant differences in the laws authorizing the OSHA PSM Standard and the EPA RMP 

regulation. Because EPA specifically lists substances covered under RMP and does not establish classes 

of substances, this report separately discusses alternatives for OSHA (Section 8.1) and EPA (Section 8.2). 

(Section 8.3 briefly discusses regulatory relief absent catastrophic consequences, and Section 8.4 suggests 

improvements within the requirements of the existing PSM Standard and RMP regulation to enhance 

hazard identification and hazard evaluation.) 

8.1 Improved Coverage Under OSHA PSM 

8.1.1 Highly Reactive Substance Classification

One approach to improve management of reactive hazards is to extend OSHA PSM coverage to a class of 

“highly reactive substances,” similar to the way the existing standard defines a class of “flammable 

liquids or gases.” “Highly reactive substances” would include single components as well as 

multicomponent substances; coverage would apply to all chemical processes (as defined by OSHA PSM). 

For example, a criterion based on the heat of reaction would specify coverage if the quantity exceeded a 
Reactives Hazard Investigation 10-17-02, page 82

certain level (e.g., 100 cal/g). Alternatively, multiple criteria such as heat of reaction and total pressure 

may be a better indicator of reactivity.

With relevant criteria, the highly reactive substance classification would cover the most likely process 

deviations and inadvertent mixing scenarios leading to injury; however, it may not take into account all 

process-specific conditions, such as inadvertent mixing of unexpected chemicals or addition of an 

unexpected catalyzing agent.

Highly reactive substance classification could also include regulatory relief, as discussed in Section 8.3.

8.1.2 Coverage Based on Hazard Evaluations

A performance-based system–rather than a list of “reactive chemicals”–is suggested as another alternative 

for extending regulatory coverage of reactive hazards. Such a system would consider the risk of reactive 

chemicals, site-specific (extrinsic) factors such as siting and proximity, and conditions that create 

potentially reactive situations. Objective criteria such as the North American Industry Classification 

System (NAICS) codes, accident history, or number of employees could be used to establish coverage. 

The process hazard analysis required by OSHA PSM is an example of a performance-based approach; it 

allows for a variety of hazard analysis methodologies. A performance-based system requires experts to 

identify and evaluate all relevant reactive hazards of a process and to determine the complexity of the 

hazards analysis. If the hazard evaluation demonstrates the possibility of a catastrophic consequence, the 

process has regulatory coverage. This approach to hazard evaluation allows for both a comprehensive 

analysis and flexibility in implementation; however, if applied to reactive hazards, it requires expertise for 

implementation and regulatory evaluation.
Reactives Hazard Investigation 10-17-02, page 83

8.1.3 “Safety Case” 

A safety case approach along the lines of the Seveso63 requirements is another possible alternative for 

determining regulatory coverage. The safety case requires a detailed explanation of why a process is safe 

to operate. Again, objective criteria such as NAICS codes, thermodynamic properties, or some 

combination of those criteria previously discussed are used to establish coverage. 

The concept of a safety case comes from the requirements of the European Union/European Community 

(EU/EC) Seveso Directive (82/501/EC) and, in particular, regulations that the United Kingdom and other 

member states used to implement that directive. United Kingdom regulations (Control of Industrial 

Major Accident Hazards [CIMAH], 1984; replaced by Control of Major Accident Hazards Involving 

Dangerous Substances [COMAH] in 1999) require that major hazardous facilities produce a safety report 

or safety case.64 The requirement for a safety case is initiated by a list of chemicals and a class of 

flammables. Like the hazard analysis approach (Section 8.1.2), experts identify the reactive hazards of 

the process; if analysis shows that the proposed process is safe, it may be excluded from additional 

regulatory requirements. 

The objective of a safety case is to demonstrate to the regulatory authority that a company is fully aware 

of the hazards associated with its operations and that they are conducted in a safe manner, such that 

employees and the public are not exposed to undue risks. The regulatory authority must examine the 

safety case and communicate the results of its examination to the facility, usually within a “reasonable 

period of time.” 

 

63 On July 9, 1976, in Meda, Italy, near Seveso, a chemical reactor incident caused a release of dioxin (TCDD), 

which is a highly toxic chemical. The regulatory requirements developed as a result of this incident are referred to 

as the Seveso Directive. 

64 The concept of a safety case exists within the context of a licensing regime. Licensing mechanisms exist in the 

United States, but compliance with workplace safety requirements is not a prerequisite for license. 
Reactives Hazard Investigation 10-17-02, page 84

The safety case may be prescriptive or performance based. Although this approach is comprehensive, if 

applied to reactive hazards, it requires that regulatory agencies have expertise to assess the adequacy of 

the analysis.

8.2 Improved Coverage Under EPA RMP

Significant differences in the laws authorizing the OSHA PSM Standard and the EPA RMP regulation 

may affect the means by which EPA can revise coverage of processes containing reactive hazards. EPA 

maintains that it is required to specifically list substances covered under RMP and cannot establish classes 

of substances. For this reason, EPA individually lists flammables, rather than adopting the “class” 

approach to flammables used by OSHA.

Two states have successfully implemented or are considering a list-based approach to address coverage of 

reactive hazards that affect the public. Delaware uses the same overpressurization criterion as OSHA for 

determining the quantity of a listed substance that is covered. New Jersey is expected to include the 

criterion in its revision of the Toxic Catastrophe Prevention Act (TCPA). 

To most effectively improve reactive hazard management, coverage under the OSHA PSM Standard and 

the EPA RMP regulation should be more compatible. EPA should seek the authority needed to allow it to 

address reactive hazard coverage in a manner compatible with any revised OSHA approach.

8.3 Regulatory Relief Absent Catastrophic Consequences

Physical processing conditions and even small amounts of extraneous materials (contaminants) that may 

have catalytic properties affect both the rate at which energy is released from an “intended reaction” and 

the potential damage. For this reason, many processes–which could be otherwise covered–may not 

present a catastrophic risk to workers under reasonable worst case scenarios. Moreover, even if the 
Reactives Hazard Investigation 10-17-02, page 85

reaction “runs away,” there may be no catastrophic injury to workers because the process is designed to 

handle reasonable worst case scenarios or offers effective passive mitigation measures, such as 

containment, diking, blast walls, and adequate emergency relief systems. 

Regulations could encourage inherently safer design and mitigation by granting exemptions where such 

measures are proven to prevent catastrophic incidents. 

8.4 Improvements in OSHA PSM and EPA RMP Requirements

8.4.1 Improved Process Safety Information

The PSI element of both the OSHA PSM Standard and the EPA RMP regulation can be improved by 

requiring the inclusion of all existing information on chemical reactivity. Examples of such information 

are chemical reactivity test data, such as DSC, thermogravimetric analysis (TGA), or accelerating rate 

calorimetry; and relevant incident reports from the plant, the corporation, industry, and government. 

OSHA and EPA should require the facility to consult such resources as Bretherick’s Handbook of 

Reactive Chemical Hazards, Sax’s Dangerous Properties of Industrial Materials, and computerized tools 

(e.g., CHETAH, The Chemical Reactivity Work Sheet). 

8.4.2 Improved Process Hazard Analysis

In both the OSHA PSM Standard and the EPA RMP regulation, the PHA element does not currently 

specify the factors that must be considered to effectively manage reactive hazards. Present requirements 

should be augmented to explicitly require an evaluation of such factors as rate and quantity of heat 

generated; maximum operating temperature to avoid decomposition; thermostability of reactants, reaction 

mixtures, byproduct waste streams, and products; effect of charging rates, catalyst addition, and possible 

contaminants; and understanding the consequences of runaway reactions or toxic gas evolution.
Reactives Hazard Investigation 10-17-02, page 86

8.4.3 Improved Reporting Requirements

OSHA PSM-covered facilities are required to investigate “each incident which resulted in, or could 

reasonably have resulted in a catastrophic release of a highly hazardous chemical in the workplace” (29 

CFR 1910.119 [m] [1]). At the conclusion of an incident investigation, the company is required to 

prepare a report on the factors that contributed to the incident. At present, OSHA does not require 

submittal of these incident reports. However, mandatory submission of the reports would increase 

available data and thus improve the capability of identifying or tracking reactive incidents.

8.5 Regulatory Initiatives Under Review by New Jersey

The New Jersey Department of Environmental Protection and Energy is presently considering amendment of 

its TCPA to establish coverage of reactive hazards that might affect the public. The State has asked for 

stakeholder input on the following proposition (paraphrased):

Processes having a reactive hazard with a heat of reaction of 100 calories per gram will be 

regulated under the NJ TCPA when the quantity of reactive hazard contained in the process 

equals or exceeds the threshold quantity calculated to result in a 2.3 psi overpressure wave 

endpoint at a distance of 100 meters or a lesser distance to the source boundary.

New Jersey is also considering whether it should have varying compliance requirements for covered 

processes. Less stringent requirements are proposed for covered processes where the reactive hazard 

substance is only stored in shipping containers and handled, with no emptying or filling. The State is 

proposing that a covered process could escape regulation under TCPA if the facility provides evidence 

that the reactive hazard substance is not capable of producing an explosion or deflagration overpressure. 
Reactives Hazard Investigation 10-17-02, page 87

9.0 Conclusions

1. Reactive incidents are a significant chemical safety problem. 

2 The OSHA PSM Standard has significant gaps in coverage of reactive hazards because it is based 

on a limited list of individual chemicals with inherently reactive properties.

3. NFPA instability ratings are insufficient as the sole basis for determining coverage of reactive 

hazards in the OSHA PSM Standard. 

4. The EPA Accidental Release Prevention Regulations (40 CFR 68) have significant gaps in 

coverage of reactive hazards. 

5. Using lists of chemicals is an inadequate approach for regulatory coverage of reactive hazards. 

Improving reactive hazard management requires that both regulators and industry address the 

hazards from combinations of chemicals and process-specific conditions rather than focus 

exclusively on the inherent properties of individual chemicals. 

6. Reactive incidents are not unique to the chemical manufacturing industry. They also occur in 

many other industries where chemicals are stored, handled, or used. 

7. Existing sources of incident data are not adequate to identify the number, severity, and causes of 

reactive incidents or to analyze incident frequency trends.

8. There is no publicly available database for sharing lessons learned from reactive incidents.

9. Neither the OSHA PSM Standard nor the EPA RMP regulation explicitly requires specific 

hazards, such as reactive hazards, to be examined when performing a process hazard analysis. 

Given that reactive incidents are often caused by inadequate recognition and evaluation of 
Reactives Hazard Investigation 10-17-02, page 88

reactive hazards, improving reactive hazard management involves defining and requiring relevant 

factors (e.g., rate and quantity of heat and gas generated) to be examined within a process hazard 

analysis. 

10. The OSHA PSM Standard and the EPA RMP regulation do not require the use of multiple 

sources when compiling process safety information.

11. Publicly available resources65 are not always used by industry to assist in identifying reactive 

hazards. 

12. There is no publicly available database to share reactive chemical test information. 

13. Current good practice guidelines on how to effectively manage reactive hazards throughout the 

life cycle 66 of a chemical manufacturing process are neither complete nor sufficiently explicit.

14. Given the impact and diversity of reactive hazards, optimum progress in the prevention of 

reactive incidents requires both enhanced regulatory and nonregulatory programs.

 

65 NOAA’s The Chemical Reactivity Worksheet, ASTM’s CHETAH, and Bretherick’s Database of Reactive 

Chemical Hazards.

66 “ Life cycle” refers to all phases of a chemical manufacturing process–from conceptualization, process R&D, 

engineering design, construction, commissioning, commercial operation, and major modification to 

decommissioning.
Reactives Hazard Investigation 10-17-02, page 89

10.0 Recommendations

Occupational Safety and Health Administration (OSHA)

1. Amend the Process Safety Management Standard (PSM), 29 CFR 1910.119, to achieve more 

comprehensive control of reactive hazards that could have catastrophic consequences. 

(2001-01-H-R1)

• Broaden the application to cover reactive hazards resulting from process-specific conditions 

and combinations of chemicals. Additionally, broaden coverage of hazards from self-reactive 

chemicals. In expanding PSM coverage, use objective criteria. Consider criteria such as the 

North American Industry Classification System (NAICS), a reactive hazard classification 

system (e.g., based on heat of reaction or toxic gas evolution), incident history, or 

catastrophic potential. 

• In the compilation of process safety information, require that multiple sources of information 

be sufficiently consulted to understand and control potential reactive hazards. Useful sources 

include: 

- Literature surveys (e.g., Bretherick’s Handbook of Reactive Chemical Hazards, Sax’s 

Dangerous Properties of Industrial Materials).

- Information developed from computerized tools (e.g., ASTM’s CHETAH, NOAA’s The 

Chemical Reactivity Worksheet).
Reactives Hazard Investigation 10-17-02, page 90

- Chemical reactivity test data produced by employers or obtained from other sources (e.g., 

differential scanning calorimetry, thermogravimetric analysis, accelerating rate 

calorimetry). 

- Relevant incident reports from the plant, the corporation, industry, and government.

- Chemical Abstracts Service. 

• Augment the process hazard analysis (PHA) element to explicitly require an evaluation of 

reactive hazards. In revising this element, evaluate the need to consider relevant factors, such 

as:

- Rate and quantity of heat or gas generated.

- Maximum operating temperature to avoid decomposition.

- Thermal stability of reactants, reaction mixtures, byproducts, waste streams, and 

products.

- Effect of variables such as charging rates, catalyst addition, and possible contaminants.

- Understanding the consequences of runaway reactions or toxic gas evolution.

2. Implement a program to define and record information on reactive incidents that OSHA 

investigates or requires to be investigated under OSHA regulations. Structure the collected 

information so that it can be used to measure progress in the prevention of reactive incidents that 

give rise to catastrophic releases. (2001-01-H-R2)
Reactives Hazard Investigation 10-17-02, page 91

 U.S. Environmental Protection Agency (EPA) 

1. Revise the Accidental Release Prevention Requirements, 40 CFR 68, to explicitly cover 

catastrophic reactive hazards that have the potential to seriously impact the public, including 

those resulting from self-reactive chemicals and combinations of chemicals and process-specific 

conditions. Take into account the recommendations of this report to OSHA on reactive hazard 

coverage. Seek congressional authority if necessary to amend the regulation. (2001-01-H-R3)

2. Modify the accident reporting requirements in RMP* Info to define and record reactive incidents. 

Consider adding the term “reactive incident” to the four existing “release events” in EPA’s 

current 5-year accident reporting requirements (Gas Release, Liquid Spill/Evaporation, Fire, and 

Explosion). Structure this information collection to allow EPA and its stakeholders to identify 

and focus resources on industry sectors that experienced the incidents; chemicals and processes 

involved; and impact on the public, the workforce, and the environment. (2001-01-H-R4) 

National Institute of Standards and Technology (NIST) 

Develop and implement a publicly available database for reactive hazard test information. Structure the 

system to encourage submission of data by individual companies and academic and government 

institutions that perform chemical testing. (2001-01-H-R5)

Center for Chemical Process Safety (CCPS)

1. Publish comprehensive guidance on model reactive hazard management systems. (2001-01-HR6) At a minimum, ensure that these guidelines cover:
Reactives Hazard Investigation 10-17-02, page 92

• For companies engaged in chemical manufacturing: reactive hazard management, including 

hazard identification, hazard evaluation, management of change, inherently safer design, and 

adequate procedures and training.

• For companies engaged primarily in the bulk storage, handling, and use of chemicals: 

identification and prevention of reactive hazards, including the inadvertent mixing of 

incompatible substances. 

2. Communicate the findings and recommendations of this report to your membership. (2001-01-HR7) 

American Chemistry Council (ACC) 

1. Expand the Responsible Care Process Safety Code to emphasize the need for managing reactive 

hazards. (2001-01-H-R8) Ensure that:

• Member companies are required to have programs to manage reactive hazards that address, at 

a minimum, hazard identification, hazard evaluation, management of change, inherently safer 

design, and adequate procedures and training.

• There is a program to communicate to your membership the availability of existing tools, 

guidance, and initiatives to aid in identifying and evaluating reactive hazards.

2. Develop and implement a program for reporting reactive incidents that includes the sharing of 

relevant safety knowledge and lessons learned with your membership, the public, and government 

to improve safety system performance and prevent future incidents. (2001-01-H-R9)
Reactives Hazard Investigation 10-17-02, page 93

3. Work with NIST in developing and implementing a publicly available database for reactive 

hazard test information. Promote submissions of data by your membership. (2001-01-H-R10)

4. Communicate the findings and recommendations of this report to your membership.

(2001-01-H-R11)

Synthetic Organic Chemical Manufacturers Association (SOCMA)

1. Expand the Responsible Care Process Safety Code to emphasize the need for managing reactive 

hazards. (2001-01-H-R12) Ensure that:

• Member companies are required to have programs to manage reactive hazards that address, at 

a minimum, hazard identification, hazard evaluation, management of change, inherently safer 

design, and adequate procedures and training.

• There is a program to communicate to your membership the availability of existing tools, 

guidance, and initiatives to aid in identifying and evaluating reactive hazards.

2. Develop and implement a program for reporting reactive incidents that includes the sharing of 

relevant safety knowledge and lessons learned with your membership, the public, and government 

to improve safety system performance and prevent future incidents. (2001-01-H-R13)

3. Work with NIST in developing and implementing a publicly available database for reactive 

hazard test information. Promote submissions of data by your membership. (2001-01-H-R14)

4. Communicate the findings and recommendations of this report to your membership.

(2001-01-H-R15)
Reactives Hazard Investigation 10-17-02, page 94

National Association of Chemical Distributors (NACD)

1. Expand the existing Responsible Distribution Process to include reactive hazard management as 

an area of emphasis. At a minimum, ensure that the revisions address storage and handling, 

including the hazards of inadvertent mixing of incompatible chemicals. (2001-01-H-R16)

2. Communicate the findings and recommendations of this report to your membership. 

(2001-01-H-R17)

International Association of Firefighters 

Communicate the findings and recommendations of this report to your membership. (2001-01-H-R18)

Paper, Allied-Industrial, Chemical & Energy Workers International Union (PACE)

Communicate the findings and recommendations of this report to your membership. (2001-01-H-R19)

The United Steelworkers of America

Communicate the findings and recommendations of this report to your membership. (2001-01-H-R20)

Union of Needletrades, Industrial, and Textile Employees (UNITE)

Communicate the findings and recommendations of this report to your membership. (2001-01-H-R21)

United Food and Commercial Workers International Union

Communicate the findings and recommendations of this report to your membership. (2001-01-H-R22)

American Society of Safety Engineers (ASSE)

Communicate the findings and recommendations of this report to your membership. (2001-01-H-R23)
Reactives Hazard Investigation 10-17-02, page 95

American Industrial Hygiene Association (AIHA)

Communicate the findings and recommendations of this report to your membership. (2001-01-H-R24)

By the

U.S. Chemical Safety and Hazard Investigation Board

Carolyn W. Merritt

Chair

John S. Bresland

Member

Gerald V. Poje, Ph.D.

Member

Isadore Rosenthal, Ph.D.

Member

Andrea Kidd Taylor, Dr. P.H.

Member

October 8, 2002
Reactives Hazard Investigation 10-17-02, page 96

11.0 References

American Chemistry Council (ACC), 2001. Responsible Care: Good Chemistry at Work.

Barton, John, and Richard Rogers, 1997. Chemical Reaction Hazards, A Guide to Safety, Rugby, U.K.: 

Institution of Chemical Engineers (IChemE). 

Bretherick, Leslie, P. G. Urben, and Martin J. Pitt, 1999. Bretherick’s Handbook of Reactive Chemical 

Hazards, Sixth Edition, Vol. 1, Butterworth-Heinemann.

Center for Chemical Process Safety (CCPS), 2001. Safety Alert, Reactive Material Hazards, American 

Institute of Chemical Engineers (AIChE).

CCPS, 1995a. Guidelines for Chemical Reactivity Evaluation and Application to Process Design, 

AIChE.

CCPS, 1995b, Guidelines for Safe Storage and Handling of Reactive Materials, AIChE.

CCPS, 1992. Guidelines for Hazard Evaluation Procedures, 2

nd Edition With Worked Examples, AIChE.

CCPS, 1989. Technical Management of Chemical Process Safety, AIChE.

Chemical Manufacturers Association (now American Chemistry Council [ACC]), 1989. Process Safety 

Code. 

CONSAD Corporation, 1998. Analytical Support and Data Gathering for an Economic Analysis of the 

Addition of Selected Reactive Chemicals Within the Scope of the OSHA Process Safety Management 

Standard, December 15, 1998.

HarsBook, 2001. Thematic Network on Hazard Assessment of Highly Reactive Systems (HarsNet), 

BET2-0572, Industrial and Materials Technologies Programme of the European Commission.

Health and Safety Executive (HSE), 2000. Designing and Operating Safe Chemical Reaction Processes, 

Rugby, U.K.: HSE Books.

Hofelich, T. C., B. A. Prine, and N. E. Scheffler, 1997. “A Quantitative Approach to Determination of 
Reactives Hazard Investigation 10-17-02, page 97

NFPA Reactivity Hazard Rating Parameters,” Process Safety Progress, Vol. 16, No. 3, Fall 1997, 

pp. 121-125.

Grewer, T., 1994. Thermal Hazards of Chemical Reactions, Industrial Safety Series, Vol. 4, Elsevier 

Science.

Koseki, Hiroshi, and Y. Iwata, 2001. “Study on Risk Evaluation of Hydroxylamine/Water Solution,” 

Proceedings, Be yond Regulatory Compliance, Making Safety Second Nature, Mary Kay O’Connor 

Process Safety Center, Texas A&M University, October 2001.

Lewis, Richard J., 1996. Sax’s Dangerous Properties of Industrial Materials, Ninth Edition, Van 

Nostrand Reinhold. 

Melham G.A., and E.S. Shanlet, 1995. “On the Estimation of Hazard Potential for Chemical Substances,” 

International Symposium on Runaway Reactions and Pressure Relief Design, AIChE.

National Association of Chemical Distributors (NACD), 2002. Responsible Distribution Process Code of 

Management Practice, April 2002. 

National Fire Protection Association (NFPA), 2001a. Fire Protection Guide to Hazardous Materials, 13th

edition.

NFPA, 2001b. System for the Identification of the Hazards of Materials for Emergency Response, NFPA 

704.

NFPA, 1994. Hazardous Chemical Data, NFPA 49.

National Transportation Safety Board (NTSB), 2000. Hazardous Materials Accident Brief, Whitehall, 

Michigan, Chemical Reaction During Cargo Transfer, June 4, 1999.

Occupational Safety and Health Administration (OSHA), 1996. Hazard Information Bulletin, Water 

Reactive Chemicals, Hazardous Materials Not Covered Under 29 CFR 1910.119, July 3, 1996.

Pohanish, Richard P., and Stanley A. Greene, 1997. Rapid Guide to Chemical Incompatibilities, John 

Wiley & Sons, Inc.

Stoessel, F., 1993. “What is Your Thermal Risk?” Chemical Engineering Progress, AIChE, October 
Reactives Hazard Investigation 10-17-02, page 98

1993.

Synthetic Organic Chemical Manufacturers Association (SOCMA), 1999. Guide to Process Safety, 2

nd

Edition.

United Nations 1999. Recommendations on the Transport of Dangerous Goods, Test and Criteria (the 

Orange Book), 3rd Edition.

U.S. Chemical Safety Board (USCSB), 2002a. Case Study, The Explosion at Concept Sciences: Hazards 

of Hydroxylamine, No. 1999-13-C-PA, March 2002.

USCSB, 2002b. Investigation Report, Thermal Decomposition Incident, BP Amoco Polymers, Inc., 

Augusta, Georgia, March 13, 2001, No. 2001-03-I-GA, June 2002.

USCSB, 2001. Safety Bulletin, Management of Change, No. 2001-04-SB, August 2001.

USCSB, 2000. Investigation Report, Chemical Manufacturing Incident, Morton International, Inc., 

Paterson, New Jersey, April 8, 1998, No. 1998-06-I-NJ.

U.S. Environmental Protection Agency (USEPA), 2000. “Case Study: Waste Fuel/Oxidizer Reaction 

Hazards,” Prevention of Reactive Chemical Explosions, EPA 550-F00-001, Office of Solid Waste 

and Emergency Response, April 2000.

USEPA, 1999. “Case Study: Phenol-Formaldehyde Reaction Hazards,” How to Prevent Runaway 

Reactions, EPA-550-F99-004, Office of Solid Waste and Emergency Response, August 1999.

USEPA, 1997. Explosion Hazards From Ammonium Nitrate, EPA 550-F97-002d, Office of Solid Waste 

and Emergency Response, December 1997.

USEPA-Occupational Safety and Health Administration (OSHA), 1999. Joint Chemical Accident 

Investigation Report on BPS, Inc., West Helena, Arkansas, April 1999.

USEPA-OSHA, 1997. Joint Chemical Accident Investigation Report, Napp Technologies, Inc., Lodi, 

New Jersey, October 1997.
Reactives Hazard Investigation 10-17-02, page 99

APPENDIX A: Glossary

Adiabatic calorimetry: Chemical testing technique that determines the self-heating rate and pressure data 

of a chemical under near-adiabatic conditions. (“Adiabatic” refers to any change in which there 

is no gain or loss of heat.) This measurement technique conservatively estimates the conditions 

for, and consequences of, a runaway reaction.

Acid-base reaction: Chemical reaction involving the transfer of a hydrogen ion from an acidic substance 

to a basic substance.

Blast: Potentially damaging pressure or shock wave produced by an explosion.

Catalyst: Substance that usually increases the rate of a chemical reaction without changing its own 

composition. 

Chemical incompatibility: Type of reactive hazard that occurs when a chemical is mixed or comes in 

contact with other chemicals, or process materials, resulting in an uncontrolled and often violent 

reaction.

Chemical reaction: Interaction of substances in which they undergo change of composition and 

properties due to changes in molecular structure of the constituent atoms or molecular fragments.

Chlorination: Reaction of substances with chlorine whereby chlorine atoms are chemically integrated 

into the original chemical molecule.

Contaminant: Any substance that enters a process where it is not normally found.

Decomposition: Chemical reaction that leads to the breakdown or decomposition of a chemical into 

smaller molecules or elements, often with the liberation of energy and product gases.
Reactives Hazard Investigation 10-17-02, page 100

Differential scanning calorimetry (DSC): Chemical testing technique that is used to establish 

approximate temperature ranges in which a substance undergoes an exothermic decomposition 

and to determine the energy output of those reactions; may also be used to study endothermic 

processes, such as melting. DCS data provide very simple and approximate reaction kinetics. 

Differential thermal analysis (DTA): Chemical testing technique that produces similar data to DSC. 

DTA uses temperature differences to generate test results; DSC has largely replaced the DTA 

technique as a screening tool for obtaining chemical hazard test data. 

Endothermic reaction: Chemical reaction that absorbs heat. 

Explosion: Sudden release of energy that causes a blast or shock wave; may lead to personal injury or 

structural damage.

Exothermic reaction: Chemical reaction that liberates heat.

Halogenation: Chemical reaction of substances with a halogen–typically, fluorine, chlorine, and 

bromine. See “chlorination.”

Hazard: Chemical or physical condition that has the potential to cause harm to human life, property, or 

the environment. 

Hazard evaluation: Systematic process to investigate hazards, assess potential consequences, and 

establish a design and operating basis for safety.

Hazard and operability analysis (HAZOP): A qualitative hazard analysis technique to identify and 

evaluate process hazards and potential operating problems; focuses on a detailed and systematic 

examination of process deviations and their consequences.
Reactives Hazard Investigation 10-17-02, page 101

Human factors: Discipline concerned with designing machines, operations, and work environment to 

match human capacities and limitations.

Hydrolysis: Chemical reaction of a substance with water; may lead to undesired runaway reactions and 

generation of gaseous molecules, such as hydrogen, hydrogen chloride, and alkanes.

Impact or thermally sensitive material: Material that decomposes rapidly when subjected to heat or 

impact, resulting in a potentially explosive release of energy.

Layers of protection: Multiple, redundant, or diverse safeguards to prevent an incident from occurring 

regardless of the initiating event or the performance of any single safeguard.

Management system: Structured, systematic method to implement an identified set of activities with 

assigned responsibilities and accountability.

Mixing calorimetry: Technique used to measure heat evolved upon instantaneous mixing of two or more 

chemicals; usually designed to be rapid (15 to 45 minutes), operating over the range of -50 to 200 

degrees Celsius (°C).

Monomers: Chemicals that are the simple starting units from which polymers are made; they are reactive 

and sometimes unstable under ambient conditions.

Nitration: Chemical reaction of a substance in which the nitro group (-NO2) is introduced into the 

molecule; often accomplished under highly reactive conditions using mixtures of nitric and 

sulfuric acids at high temperatures. Byproducts of the reaction may have explosive properties; if 

reaction control is lost, may lead to vigorous and strongly exothermic runaway reactions due to 

oxidation of the reactants. 

Oxidation: Chemical reaction in which the oxidation state of a molecule increases due to the abstraction 
Reactives Hazard Investigation 10-17-02, page 102

of electrons; often occurs when oxygen or other oxidizing material combines with the reacting 

substance.

Oxidation-reduction (REDOX): Chemical reaction in which an element loses (oxidation) or gains 

(reduction) an electron.

Oxidizer: Material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or 

initiate combustion.

Polymer: Large chemical molecule made up of repeating smaller units (e.g., polyethylene is a synthetic 

polymer made up of repeating ethylene units).

Polymerization: Chemical reaction in which one or more relatively simple molecules (monomers) 

combine to form a more complex compound (polymer). 

Process hazard analysis: Organized effort to identify and evaluate hazards associated with chemical 

processes; normally involves the use of qualitative techniques to identify and assess the 

significance of hazards.

Process-specific factors: Conditions such as temperature, pressure, quantities handled, chemical 

concentrations, catalytic effects, and addition rates.

Process life cycle: All phases of a process from its conception through chemical and process research 

and development (R&D), engineering design, construction, commissioning, commercial 

operation, major modification, and decommissioning.

Public: Any person other than employees or contractors at or near a facility.

Public impact: Known injury to the public, offsite evacuation, or shelter-in-place.
Reactives Hazard Investigation 10-17-02, page 103

Reactive incident: Sudden event involving an uncontrolled chemical reaction–with significant increases 

in temperature, pressure, or gas evolution–that has caused, or has the potential to cause, serious 

harm to people, property, or the environment.

Reactive chemical process safety: Systematic identification, evaluation, and control of reactive hazards 

at all phases of the production life cycle–from R&D to pilot plant, change management, and 

decommissioning; and for all types of operations–from storage or manufacturing to packaging or 

waste processing. 

Reactive hazard: Reactive properties and physical conditions of a single chemical or mixture that have 

the potential to generate heat, energy, and gaseous byproducts that have the potential to do harm.

Reactivity: Tendency of substances to undergo chemical change.

Reaction calorimetry: Chemical testing technique that determines thermodynamic and kinetic 

information on a desired reaction under conditions closely similar to those of a larger-scale plant; 

measures heat flow (production of desired process) and product generation (without knowledge of 

heat of reaction), and facilitates isothermal and temperature-ramped experiments.

Root cause: Primary reason why an incident occurred, developed through systematic analyses.

Runaway reaction: Reaction that is out of control because the heat generation rate exceeds the rate at 

which heat is removed to cooling media and surroundings. 

Self-reactivity: Chemical reaction that involves only one chemical substance.

Thermal gravitational analysis (TGA): Chemical testing technique that precisely measures weight loss 

(due to gas forming reactions) as a function of temperature and time.
Reactives Hazard Investigation 10-17-02, page 104

Toll manufacturer: Facility that blends, mixes, processes, or packages chemicals.

Worst case scenario: The most severe postulated scenario involving an uncontrolled reaction.

Water reactive: Substance that reacts with water, often producing a vigorous exothermic reaction.
Reactives Hazard Investigation 10-17-02, page 105

APPENDIX B: Surveys

B.1 Industry Survey

The U.S. Chemical Safety and Hazard Investigation Board (CSB) conducted a survey of companies that 

store, handle, and process chemicals. The objective of the survey was to examine current management 

practices with regard to reactive hazard management. Survey responses served primarily to highlight 

good practices, but also to point out areas for potential improvement. The survey questionnaire is posted 

on the CSB website at http://www.chemsafety.gov/info/Reactives.Survey.Final.pdf.

The survey was designed, administered, and analyzed by CSB staff with the support of EQE International, 

a consulting company with expertise in chemical process safety. Questions focused on the application of 

systematic programs, procedures, and practices for reactive chemicals management at the site level. 

Respondents were asked to provide details about good management practices in all phases of the 

manufacturing life cycle, including research and development (R&D), engineering, capital projects, 

commissioning, plant operations, and management of change (MOC). Where possible, respondents were 

asked to provide information about actual, routine practices.

The nine surveyed companies volunteered to participate. Industry trade associations (American 

Chemistry Council [ACC], National Association of Chemical Distributors [NACD], Synthetic Organic 

Chemical Manufacturers Association [SOCMA]) and professional societies (Center for Chemical Process 

Safety [CCPS]) were asked to identify possible survey candidates–small, medium, and large sites or 

companies with reactive chemical hazard management programs or practices in place. As such, the 

survey was not intended to represent the practices of the chemical industry as a whole; in fact, the survey
Reactives Hazard Investigation 10-17-02, page 106

 respondents more likely represent the “upper tier” of companies/facilities handling reactive chemicals 

and managing the related hazards.

To supplement the industry survey, CSB staff conducted five selected site visits at industry facilities that 

have implemented programs for managing reactive hazards. The first-hand information gathered in these 

visits provided an understanding of the challenges involved in developing a systematic management 

program for reactive hazards.

All nine survey participants were primarily engaged in chemical manufacturing, representing synthetic 

organic chemicals, pharmaceuticals, specialty chemicals, fine organics, polymers, agrochemicals, and 

contract manufacturing. Most considered their site to use many reactive chemicals and highly reactive 

chemicals. Interpretation of the term “highly reactive” was left to the participant. Seven of the nine 

survey respondents were member companies of ACC; four of nine were member companies of SOCMA; 

and five of nine were CCPS sponsors. 

Considering the limitations of the industry survey–including the small number of respondents–it is 

important to correspondingly recognize that the conclusions are also limited. Although representative 

small, medium, and large companies and sites were surveyed, the conclusions of this investigation do not 

support a differentiation among the practices of small versus large companies. 

B.2 SOCMA Survey

SOCMA conducted a survey of members during its April 2001 Responsible Care Conference on 

Managing Reactive Chemicals. However, eight of the 10 respondents represented facilities with less than 

100 employees. 
Reactives Hazard Investigation 10-17-02, page 107

APPENDIX C: Site Visits

C.1 Company Profiles

Company A is a major pharmaceutical manufacturer with worldwide operations. The U.S. Chemical 

Safety and Hazard Investigation Board (CSB) staff visited a site with both pilot-plant facilities and 

pharmaceutical manufacturing operations. The company is continually developing new and innovative 

chemistry, which results in frequent changes in the chemicals handled and manufacturing techniques 

used. 

Company B is a diversified chemical manufacturing company with worldwide operations. CSB staff 

visited the corporate headquarters, which also houses extensive chemical manufacturing operations. The 

site also has an extensive thermal hazards testing capability. CSB met with corporate staff, site 

manufacturing personnel, and thermal hazards chemists. The Company B testing laboratory evaluates a 

range of chemicals. 

Company C is a small custom chemical manufacturer. Contract manufacturing accounts for its entire 

business. CSB staff visited a small manufacturing site with several batch chemical manufacturing 

operations. The nature of custom chemical manufacturing translates into very frequent changes in 

chemicals handled and processed.

Company D is a large pharmaceutical manufacturer with worldwide operations. CSB staff visited a pilotplant facility and thermal hazards laboratory. Pilot-plant operations included the use of several batch 

chemical reactors. Like Company A, this company also frequently changes chemicals handled and 

manufacturing techniques.
Reactives Hazard Investigation 10-17-02, page 108

Company E is a large chemical manufacturer with worldwide operations. CSB staff visited a mediumsized manufacturing site. Operations included storage and handling/processing of monomers, as well as 

extensive batch polymerization. The site uses standardized manufacturing methods and typically handles 

a specific set of chemicals.

C.2 Analysis of Practices for Reactive Chemical Hazard Management

C.2.1 Company A (Major Pharmaceutical Manfacturer) 

C.2.1.1 Program Philosophy

• Reactive chemical hazard management is one element of an overall process safety program, 

but is emphasized through thermal hazards analysis.

• Capabilities and practices are driven by the business need for rapid scaleup and high product 

quality.

• The corporate environmental health and safety (EHS) group provides technical resources 

(including expertise in reactive chemicals).

• The corporate research and development (R&D) facility has sophisticated thermal hazards 

capability/expertise.

C.2.1.2 Hazard Identification and Testing Program

• The company employs a phased approach to identify hazards, as outlined below:
Reactives Hazard Investigation 10-17-02, page 109

Company A, Hazard Identification

Stage Activity

Research Literature search

Pilot plant (process 

development)

Screening test prior to pilot plant

Production Additional tests as indicated by process 

hazard analysis (PHA)

• Scaleup to pilot plant is the key step in identifying and controlling reactivity hazards.

• A checklist approach is used to gather process safety information (PSI) prior to scaleup to 

pilot plant.

- Basic process/chemical data–material safety data sheet (MSDS), special handling 

requirements, pressure, temperature, gaseous byproducts, and waste streams; includes a 

list of potentially hazardous chemic al interactions.

- Reaction safety–thermal test data, hazardous bond groups, and exothermic reactions.

- Powder handling/milling–dust explosion issues.

• The company is beginning to use chemical interaction matrices as an input to PHA review.

• The company has a well-equipped laboratory for thermal hazards screening and sophisticated 

reaction calorimetry.
Reactives Hazard Investigation 10-17-02, page 110

• Small quantities and the high cost of making the product limit the amount of material 

available for R&D testing. 

• Differential scanning calorimetry (DSC) and dust explosion tests are usually conducted 

before a new chemical goes into the pilot-plant phase.

• Thermal hazards data are accessible through the company intranet.

C.2.1.3 Hazard Evaluation 

• The company conducts process hazards evaluation of all new or modified products/processes.

• PHA techniques involve a combination of “what if” for unit operations and hazard and 

operability (HAZOP) for both equipment- and procedural-based deviations. 

• Thermal hazards testing staff play a key role on the PHA team. 

• The thermal hazards laboratory, in consultation with pilot-plant engineering, typically assess 

emergency venting scenarios and requirements for runaway reaction hazards.

• Over 1,300 equipment configuration changes per year account for extensive use of 

management of change (MOC).

C.2.1.4 Risk Reduction/Controls

• PHA forms the basis for identifying needed controls. 

• Small-scale batch equipment is typically “over designed” for multipurpose use.
Reactives Hazard Investigation 10-17-02, page 111

• The company has in place numerous checks and balances to prevent human error; quality 

assurance (QA)-driven processes require validation (secondary checks/rechecks) of operator 

actions, sampling/analysis, etc. 

C.2.1.5 Communications and Training

• The pharmaceutical industry has no official EHS trade group that develops codes of practice 

equivalent to Responsible Care.

• The company recognizes the need for better and more formal sharing of lessons learned and 

for support of an improved industry incident database. 

C.2.2 Company B (Diversified Chemical Manufacturer)

C.2.2.1 Program Philosophy

• The reactives program focuses on preventing uncontrolled chemical reactions that have the 

potential to cause loss or injury or environmental harm. 

• Reactive hazards are addressed separately and uniquely from other process safety factors.

• The reactives program involves the interaction of several diverse technical experts to study 

the chemistry and process, looking for risk reduction opportunities; in-house expertise is 

available to handle reactive chemical issues.

• The company perceives its reactives program as adding value rather than being regulatory 

driven.
Reactives Hazard Investigation 10-17-02, page 112

• Value is defined as having a competitive advantage; reducing damage to the facility, 

property, and equipment; reducing injuries; and being accepted as a good member of the 

community.

• The company advocates an outside-in approach, using reviewers from outside the technology 

or business to help identify hazards that may have been overlooked.

• Program philosophy focuses on identifying potential accident scenarios. 

• The reactives program emphasizes both self-reactivity (instability) and binary reactivity.

• The company strongly supports owner responsibility on the part of the production leader–

knowing reactive chemicals and their process hazards, participating in the establishment and 

maintenance of corporate memory, and demonstrating a fundamental understanding of 

reactive chemical hazards within the facility within 90 days of any new assignment.

• Corporate guidelines require that individuals develop an understanding of reactive hazards 

based on data collection, hazard evaluation, training, etc.

• Corporate standards, approved by the EHS board, are established for audit/review; 

performance-based training; MOC, which is approved by the area production leader; and 

training, which addresses worst case scenarios, cardinal rules, and lines of defense.

• There are corporate guidelines for application of the reactive chemicals program, formation 

of a reactive chemicals team, project reviews, and chemicals testing.
Reactives Hazard Investigation 10-17-02, page 113

• Key deliverables are capital project reviews; new production leader reviews; existing facility 

hazard reviews on a 3- to 5-year cycle; research facility reviews; and a formal training and 

awareness program.

• The company offers as key resources a global standard, how-to guidelines, testing 

laboratories/expertise, and computerized tools for review.

• The company offers multidisciplinary support through research, manufacturing, 27 

technology centers, and EHS. 

• Technology centers provide critical functions in establishing corporate memory, documenting 

findings and implementing preventive measures, submitting data to CCPS, sharing operating 

knowledge across the company, and establishing effective process technologies.

C.2.2.2 Hazard Identification and Testing Program

• Key elements of reactive hazard identification are owner-initiated review, chemistry review, 

review of unit operations, review of scenarios, definition of required testing, records testing, 

and interpretation of results for owner.

• Testing centers are geographically distributed and include contractor support.

• Testing includes screening (e.g., literature research, mixing calorimetry, thermodynamic 

calculations, estimation of heats of reaction, DSC, flash point calculations), quantitative 

assessment (e.g., accelerated rate calorimetry, specialized calorimetry), and scaleup (vent size 

packaging [VSP], modeling, reaction calorimetry).
Reactives Hazard Investigation 10-17-02, page 114

• The program focuses on binary and higher levels of reactivity in addition to self-reactivity 

(instability).

• An incompatibility-mixing chart facilitates the prediction of reactive mixing hazards. 

• The reactive testing laboratories cover fire, dust, kinetics, high energy, and thermodynamics. 

C.2.2.3 Hazard Evaluation 

• The company hazard review process was revised in June 1997 to combine reactive chemicals, 

loss prevention, distribution risk review, EHS review for safety and loss, project risk review, 

and technology center review.

• Each major company site has a hazard review committee to administer the standard and 

guideline. The committee includes representatives from process safety, chemistry, reactive 

chemistry, manufacturing, process engineering, pilot-plant operations, and the technology 

center.

• The outside-in approach brings people without specific knowledge of a process into reviews.

• Flowcharts are used for process overview; analysis of causes and consequences, lines of 

defense, and testing data requirements; and review of hazard checklist, schedule, and 

followup on recommendations.

• Review of work progress includes scenarios for inadvertent mixing, reaction loss-of-control, 

and instability of materials.
Reactives Hazard Investigation 10-17-02, page 115

C.2.2.4 Risk Reduction/Controls

• The need for additional controls is identified through design standards, reactive chemicals 

process hazard analysis, and technology centers. 

C.2.2.5 Communications and Training

• The communications/training challenge is to retain learning from incidents in corporate 

memory to prevent recurrence.

• The key premises of corporate memory are to never have to pay for an incident more than 

once, to learn from history and leverage across all plants and technologies, and to derive 

benefit from the experience of other companies. 

• Eighty percent of incidents are due to known chemistry hazards; it has been 6 years since the 

company’s last “unknown” chemistry incident.

• Technical centers provide small sites access to data and technical expertise for reactive 

chemicals.

• The company maintains global databases for 60,000+ tests, prior incident data for 22 years, 

and databases of all credible reactive chemical scenarios with key lines of defense for all 

technologies.

• Small sites generally have little/no capability in R&D, process engineering, reactive chemical 

testing, and chemistry.

• A global reactive chemical newsletter is published regularly and read by over 4,000 

employees worldwide.
Reactives Hazard Investigation 10-17-02, page 116

C.2.3 Company C (Custom Chemical Manufacturer)

C.2.3.1 Program Philosophy

• Management considers reactive hazard management as a subset of process safety 

management.

• The company has specific procedures for reactive chemicals hazard management.

• Management takes a proactive approach in terms of Occupational Safety and Health 

Administration (OSHA) and U.S. Environmental Protection Agency (EPA) requirements. 

The company applies the PSM Standard and the Risk Management Program (RMP) 

regulation to processes that normally do not require coverage (under threshold quantities) 

because it makes good business sense.

• Management focuses on safety-oriented programs to prevent business interruptions.

• Reactive hazards play a significant role in deciding whether to manufacture new chemicals 

onsite.

• Although the company has very limited safety resources onsite, management perceives safety 

as added value and hires individuals from organizations with a good safety culture. The 

management commitment to safety is clearly evident in each aspect of the safety program.

• When a customer requests production of a chemical, the steering committee reviews the 

inquiry and determines the initial feasibility of production; within 1 to 2 weeks, the 

committee renders a go-no go decision to the customer. Process safety plays a significant 

role in the decision process. 
Reactives Hazard Investigation 10-17-02, page 117

C.2.3.2 Hazard Identification and Testing Programs

• The customer requesting production of a chemical provides reactive hazard information 

(literature reviews, thermal test data, etc.).

• If the information is insufficient to assess reactive hazards, additional data are requested, such 

as thermal screening test data. 

• When considering development of a new process for a customer, a team is formed to assess 

potential hazards (including reactive) and to determine the technically feasibility of 

production. 

• Potential hazards (flammability, corrosivity, etc.) are reviewed to identify concerns regarding 

the storage and handling of reactive chemicals, and information is obtained from raw material 

suppliers (e.g., technical bulletins). Flashpoint, DSC, or differential thermal analysis (DTA) 

testing is typically done by the customer.

• If potential reactive hazards are identified within a proposed process, the customer is asked to 

provide additional test data. The company only occasionally contracts testing services. 

C.2.3.3 Hazard Evaluation

• Expert opinion is essential in the hazard evaluation process. 

• A hazard evaluation is performed before assessing the technical feasibility of a new process. 

Chemical handling/storage criteria, critical process conditions, quality measurements, thermal 

hazards, and post-campaign cleanup are considered in the introduction of any new 

process/product.
Reactives Hazard Investigation 10-17-02, page 118

• Once a new process is identified as feasible, it goes through a process hazard analysis 

(usually HAZOP) to evaluate issues such as reactive chemistry.

• Hazard evaluations are conducted in a team environment that typically includes a process 

engineer, EHS staff, a chemist, maintenance, a production operator, and the customer.

• Design reviews are conducted to refine requirements. Hazards are introduced to plant 

operators following laboratory work, EHS review, capital requirements review, and process 

hazard analysis. Reactivity is addressed during process hazard analysis and the initial review.

• A HAZOP is performed on all new chemicals following process review, preliminary 

equipment review, and development of preliminary standard operating procedures (SOP). 

“What-if” and checklists are typically used to review a process without process design and 

chemistry changes. 

• Process chemistry changes are evaluated for quality and EHS impacts.

• MOC and SOPs are vehicles for approving and communicating change.

C.2.3.4 Risk Reduction/Controls

• Process hazard analysis leads to risk reduction/control recommendations.

• Risk reduction/control is primarily accomplished through design measures, SOPs, and 

training.
Reactives Hazard Investigation 10-17-02, page 119

C.2.3.5 Communication and Training

• Once a new chemical is introduced into the plant, employees receive on-the-job training on 

the new production process, which covers safe operating limits, process controls, emergency 

situations, etc.

• Operators have levels of expertise. The most experienced operators (level 3) generally 

perform the majority of the process-related functions. Entry-level operators are not assigned 

this work, and level 2 operators perform these functions with supervision. 

C.2.4 Company D (Large Pharmaceutical Manufacturer)

C.2.4.1 Program Philosophy

• Reactive chemical hazard management is one element of an overall process safety program 

and is emphasized through thermal hazards evaluation.

• The program is driven by previous incidents, concern for the community, and business 

factors.

C.2.4.2 Hazard Identification and Testing

• Hazard identification is built into the design process.

• Testing is conducted regardless of supplier information.

• The program includes a preliminary screening test, team-based screening, reactive evaluation, 

and process hazard analysis. 

• The reactive hazard evaluation protocol is nonprescriptive; the type and quantity of testing is 
Reactives Hazard Investigation 10-17-02, page 120

based on judgment.

• National Fire Protection Association (NFPA) ratings are used for original screening; no 

chemicals with NFPA ratings of 3 or 4 are used at the site.

• The company has a full range of reactive chemical test equipment onsite.

C.2.4.3 Hazard Evaluation

• A complete evaluation is conducted during process development, including testing and 

system evaluation of process aberrations.

• A multidisciplinary team approach is used during all phases of evaluation.

• A binary interaction matrix is developed for all materials in the process, including air and 

rust.

• The PHA method is case dependent, focused on procedure, and required for every pilot-plant 

run.

• Process hazard analysis considers equipment failure, human factors–including errors of 

omission and commission, and previous incidents.

C.2.4.4 Risk Reduction and Controls

• Risk is identified at various stages in the process.

• Special setups are used to control risk.

• The process hazard analysis identifies operator training needs.
Reactives Hazard Investigation 10-17-02, page 121

• Risk assessment is qualitative.

C.2.4.5 Communications and Training

• Incident data are kept in a local database and shared both site- and company-wide.

• There is no formal pharmaceutical industry trade group that dicusses safety issues.

C.2.5 Company E (Large Chemical Manufacturer)

C.2.5.1 Program Philosophy

• Reactive chemicals hazard management is part of the overall process safety program, which 

is applied regardless of regulatory coverage.

• Codes of practice developed at the corporate level promote standardization throughout the 

company.

C.2.5.2 Hazard Identification and Testing

• Reactive chemical testing is done at the corporate level.

• The company maintains a list of chemicals that are considered to be highly hazardous based 

on such characteristics as flash point (less than 100°F), self reactivity, water reactivity, 

boiling point, and toxicity.

C.2.5.3 Hazard Evaluation

• Plants are periodically audited against rigid corporate guidelines for safe operation.

• Multidisciplinary teams conduct process hazard analyses.
Reactives Hazard Investigation 10-17-02, page 122

• Exceptions to corporate guidelines are made by committee.

• Process hazard analyses are conducted in accordance with formal procedure, with piping and 

instrumentation diagrams for reference.

C.2.5.4 Risk Reduction and Controls

• The company generates a standard MSDS for all raw materials and products.

• Corporate guidelines dictate procedures for safe limits of operation and response to a 

runaway reaction.

• Color-coded buckets and storage locations protect against inadvertent mixing of incompatible 

chemicals.

• An interaction matrix is available on the intranet. 

C.2.5.5 Communications and Training

• The company offers comprehensive training on plant safety policies.
Reactives Hazard Investigation 10-17-02, page 123

APPENDIX D: Resources

D.1 Guidelines

There are extensive writings on reactive hazard management. The term “guidelines” is used herein to 

refer to good practices that are nonmandatory and are developed through industry consortia, committees, 

professional societies, and other bodies. 

CSB analysis included guidelines that focus primarily on the process safety of reactive chemicals; other 

good practices that might include some elements of reactive process safety were not included. 

D.1.1 CCPS Guidelines Series

In 1985, the American Institute of Chemical Engineers (AIChE) established the Center for Chemical 

Process Safety (CCPS) to aid in the prevention or mitigation of catastrophic chemical accidents. CCPS 

publishes a series of Guidelines books and bulletins on good management and engineering practices, 

including the following on reactive hazard management:

• Guidelines for Chemical Reactivity Evaluation and Application to Process Design, 1995 

This publication describes the principles for evaluating chemical reactivity as an element of 

chemical process design. It outlines methods for identifying reaction hazards and 

establishing safe operating conditions. Special emphasis is placed on state-of-the-art theory 

and testing methods, as well as inherent safety principles. The intended audience is those 

involved in R&D, pilot-plant, process design, and (to a lesser degree) commercial plant 

operations. The guidelines focus on technical issues; they are not intended to be a manager’s 

guide to reactive hazard management. 
Reactives Hazard Investigation 10-17-02, page 124

• Guidelines for Safe Storage and Handling of Reactive Materials, 1995

This book summarizes current industry practices for design and operation of reactive 

chemical storage and handling systems. Special emphasis is placed on the engineering design 

of storage and handling systems. The intended audience is primarily process engineers or 

others with technical responsibility–not managers. The guidelines do not cover chemical 

reactions, mixing, or blending. 

• Safety Alert, Reactive Material Hazards, 2001

This 10-page bulletin offers an introduction to reactive material hazards. It is organized 

around four key questions: Do you handle reactive materials? Can you have reactive 

interaction? What data do you need to control these hazards? What safeguards do you need 

to control these hazards?

D.1.2 Other Guidance

Other international publications offer guidance on the topic of reactive hazard management, such as:

• Chemical Reaction Hazards, A Guide to Safety, 1997

The purpose of this guidebook, written by Barton and Rogers for the Institution of Chemical 

Engineers (IChemE), is to provide a basis for good practice in assessing reactive hazards. It 

is written for those responsible for design and operation of chemical plants. It addresses 

hazards from uncontrolled exothermic activity in batch and semibatch chemical reaction 

systems as well as associated process equipment.
Reactives Hazard Investigation 10-17-02, page 125

• Designing and Operating Safe Chemical Reaction Processes, 2000

The intent of this book, published by the Health and Safety Executive (HSE) of the United 

Kingdom, is to guide programs for small- and medium-sized chemical manufacturing 

companies using batch and semibatch manufacturing processes. Its intended audience is 

those directly responsible for the development, design, and operation of chemical plants and 

processes, particularly process chemists and process engineers. The objectives of the HSE 

guidance are to:

- Increase awareness of potential reactive hazards. 

- Assist in the assessment of risks.

- Provide a systematic approach for the design, operation, and control of chemical 

reactions in batch and semibatch processes.

- Advise on safe management procedures.

- Advise on maintenance, training, and information needs to prevent and control reactive 

hazards.

D.2 Future Guidance 

At least two efforts are currently underway to develop additional guidance in the area of reactive hazard 

management: 

• CCPS project on the management of reactive chemical hazards

As the result of a number of recent incidents caused by inappropriate handling of reactive 

chemicals, CCPS initiated a project in 2001 to develop additional management guidelines for 

reactive hazards. A CCPS technical steering committee documented the urgent need for 
Reactives Hazard Investigation 10-17-02, page 126

comprehensive “best practice” guidelines.

The audience is expected to be process safety professionals, engineers, chemists, and other 

technical personnel who generate data and design processes that involve reactive chemicals. 

Manufacturing personnel who operate such facilities are also expected to benefit through 

improved understanding of risks. 

• Hazard Assessment of Highly Reactive Systems Thematic Network (HarsNet).

HarsNet is a thematic network project sponsored by the European Commission’s Industrial 

and Materials Technologies Program. It is coordinated through the Instituto Químico de 

Sarrià, with participation by government organizations, universities, major companies (e.g., 

Dow, BASF, and CIBA), and private testing services. 

The objectives of HarsNet are to: 

- Analyze existing methodologies for thermal hazard assessment and prevention.

- Prepare guidelines for thermal hazard assessment and prevention.

- Disseminate knowledge and methodologies to small- and medium-sized enterprises.

- Provide technical support to small- and medium-sized enterprises.

HarsNet maintains that reactive chemical testing and analysis is too complex for most smalland medium-sized companies because of the wide spectrum of processes and equipment 

involved. The project seeks to provide an industry guide for estimating the thermal hazard of 

a chemical synthesis without sophisticated testing and analysis.
Reactives Hazard Investigation 10-17-02, page 127

D.3 ASTM Codes and Standards

The American Society for Testing and Materials (ASTM) is a not-for-profit organization that provides a 

forum for the development and publication of voluntary consensus standards for materials, products, 

systems, and services.67 One ASTM committee (E27) develops standardized physical and chemical test 

methods on the hazard potential of chemicals, including but not limited to reactive hazards. The 

committee has developed standard analytical methods for calorimetry studies in addition to a standard 

guide for determining binary chemical compatibility (ASTM, 2000). 

ASTM also distributes the computer program CHETAH (Chemical Thermodynamic and Energy Release 

Evaluation), a tool for predicting both thermodynamic properties and certain reactive hazards associated 

with a pure chemical, a mixture of chemicals, or a chemical reaction.

D.4 Select Resources on Reactive Hazards

A variety of tools and resources are available to aid in the recognition of reactive hazards. Table D-1 

provides a list and brie f description of selected literature resources and computerized tools. 

 

67 ASTM standards are developed voluntarily and used voluntarily. They become legally binding only when a 

government body makes them so or when they are cited in a contract
Reactives Hazard Investigation 10-17-02, page 128

Table D-1

Select Resources on Reactive Hazards

Title Contents Source

Bretherick’s Handbook of Reactive 

Chemicals

Summaries of reactivity, 

incompatibility, and other 

dangerous properties of individual 

substances either alone or in 

combination; case histories

Butterworth-Heinemann 

Sax’s Dangerous Properties of 

Industrial Materials

Summaries of reactivity, 

incompatibility, and other 

dangerous properties; applicable 

standards and recommendations; 

hazard rating

VanNostrand Reinhold (Lewis) 

Rapid Guide to Chemical 

Incompatibilities

Summaries of known effects of 

dangerously reactive substances

Wiley and Sons (Pohanish and 

Greene)

The Chemical Reactivity 

Worksheet

Database of reactivity information

for more than 4,000 common 

chemicals; includes information on 

special hazards of each chemical 

and whether a chemical reacts with 

air, water, or other materials; 

predicts the reactivity between two 

chemicals

National Oceanic and 

Atmospheric Administration 

(NOAA)

CASREACT Database of abstracts related to 

reaction chemistry, including 

hazard/safety information

American Chemical Society 

(Chemical Abstract Service) 

Chemical Hazards Response 

Information System (CHRIS) 

Database on chemical and physical 

properties; guides to compatibility 

of chemicals

U.S. Coast Guard (USCG)

Material Safety Data Sheets 

(MSDS)

Data on chemical and physical 

properties, and other dangerous 

properties

Chemical manufacturer

Guidelines for Chemical Reactivity 

Evaluation and Application to 

Process Design

Fundamentals for identification and 

evaluation of reactive hazards

CCPS

Guidelines for Safe Storage and 

Handling of Reactive Materials

Design of storage and handling 

systems for reactive chemicals

CCPS

Reactive Material Hazards, What 

You Need to Know

Introduction to reactive issues CCPS

Safety and Runaway Reactions Articles on reactive hazards Institute for Systems 

Informatics and Safety 

Chemical Reaction Hazards, A 

Guide to Safety

Fundamentals of reactive hazards IChemE (Barton and Rogers)

Designing and Operating Safe 

Chemical Reaction Processes

Safe design and operation of plants 

and processes for chemical 

reactions

HSE

Safety of Reactive Chemicals and Evaluation of reactive hazards and Elsevier (Yoshida, Wada, and 
Reactives Hazard Investigation 10-17-02, page 129

Title Contents Source

Pyrotechnics case histories Foster)

CRC Handbook of Chemistry and 

Physics

Data on chemical properties, 

especially thermochemistry, 

kinetics, and molecular structure

CRC Press (Lide)

Encyclopedia of Chemical 

Technology

Articles on chemical manufacturing 

of either single substances or groups 

of substances.

Wiley and Sons ( Kirk-Othmer)

Chemistry of Hazardous Materials Fundamentals of hazardous 

properties

Brady, Prentice-Hall (Meyer)

Ashford’s Dictionary of Industrial 

Chemicals

Hazardous properties of particular 

chemicals

Wavelength Publications

A Comprehensive Guide to the 

Hazardous Properties of Chemical 

Substances

Correlates the chemical structure of 

compounds to their hazardous 

properties

Wiley and Sons (Patnaik)

Sittig’s Handbook of Toxic and 

Hazardous Chemicals and 

Carcinogens

Data on chemical properties and 

chemical incompatibility 

William Andrew Publishing

Hazardous Chemicals Desk 

Reference

Chemical property data on safe 

handling and storage, applicable 

standards and recommendations, 

hazard rating

Wiley and Sons (Lewis)

NFPA 491M Manual of Hazardous 

Chemical Reactions

Data on hazardous chemical 

reactions

National Fire Protection 

Association (NFPA)

NFPA 43 B Storage of Organic 

Peroxide Formulations

Hazards of peroxides NFPA

NFPA 49 Hazardous Chemicals 

Data

Chemical hazard information, 

including reactivity data

NFPA

NFPA 325 Fire Hazard Properties 

of Flammable Liquids, Gases, and 

Volatile Solids

Chemical hazard information, 

including reactivity ratings

NFPA

NFPA 430 Storage of Liquid and 

Solid Oxidizers

Hazards of oxidizers NFPA
Reactives Hazard Investigation 10-17-02, page 130

Appendix E: Hazard Investigation Data Sources

Title Source CSB Action

Process Safety Incident Database Center for Chemical Process 

Safety (CCPS)/American 

Institute of Chemical Engineers 

(AIChE)

Proprietary - unavailable

National Response Center (NRC) Data U.S. Coast Guard (USCG) Retrieved information

Integrated Management Information System (IMIS) Occupational Safety and Health 

Administration (OSHA)

Retrieved information

The Accident Database Institution of Chemical 

Engineers (IChemE)

Retrieved information

Accidental Release Information Program (ARIP) U.S. Environmental Protection 

Agency (EPA) 

Retrieved information

RMP*Info (Five-Year Accident History Data) EPA Retrieved information

Major Hazard Incident Data Service (MHIDAS) Health and Safety Executive, 

United Kingdom (HSE)

Retrieved information

Chemical Incident Reports Center (CIRC) U.S. Chemical Safety and 

Hazard Investigation Board 

(CSB)

Retrieved information

Fire Incident Data Organization Database National Fire Protection 

Association (NFPA)

Retrieved information

Reports of Chemical Safety Occurrences at U.S. 

Department of Energy (DOE) facilities 

DOE Retrieved information

Process Safety Code Measurement System American Chemistry Council 

(ACC)

Reviewed only

National Fire Incident Reporting System U.S. Fire Administration Reviewed only

TNO Process Safety and Dangerous Goods (FACTS) Netherlands Organisation for 

Applied Scientific Research

Reviewed only

Major Accident Reporting System (MARS) European Communities Major 

Accident Hazard Bureau 

(MAHB)

Reviewed only

Mary Kay O'Connor Process Safety Center Database Texas A&M University Reviewed only

Hazardous Substances Emergency Events Surveillance 

(HSEES) 

 MAHB Reviewed only
Reactives Hazard Investigation 10-17-02, page 131

Title Source CSB Action

The Community Documentation Centre on Industrial 

Risk (CDCIR)

 MAHB Reviewed only

Awareness and Preparedness for Emergencies at Local 

Level (APELL) 

United Nations Environmental 

Programme (UNEP)

Reviewed only

Acute Hazardous Events Database EPA Reviewed only

Census of Fatal Occupational Injuries (CFOI) U.S. Bureau of Labor Statistics Reviewed only

Process Safety Database American Petroleum Institute 

(API)

Reviewed only

The European Health and Safety Database (HASTE) European Foundation for the 

Improvement of Living and 

Working Conditions

Reviewed only

Various Chlorine Related Incident Reports Chlorine Institute Retrieved information

Hazardous Materials Incident Reports National Transportation Safety 

Board (NTSB)

Retrieved information

Fire Incident Reports NFPA Retrieved information

Annual Loss Prevention Symposium (CD ROM) CCPS Retrieved information

Bretherick's Handbook of Reactive Chemical Hazards, 

6th Ed.

Butterworth-Heinemann Retrieved information

Loss Prevention in the Process Industries F. P. Lees Retrieved information

Large Property Damage Losses in the Hydrocarbon 

Chemical Industries, A Thirty-Year Review, 18th Ed.

Marsh and McLennan Retrieved information

NAPP Technologies Chemical Accident Investigation 

Report

EPA/OSHA Retrieved information

Prevention of Reactive Chemical Explosions EPA Retrieved information

How to Prevent Runaway Reactions EPA Retrieved information

Tosco Avon Refinery Chemical Accident Investigation 

Report

EPA Retrieved information

Surpass Chemical Company Chemical Accident 

Investigation Report

EPA Retrieved information

Incidents in the Chemical Industry Due to Thermal 

Runaway Reactions

Barton and Nolan Retrieved information
Reactives Hazard Investigation 10-17-02, page 132

Title Source CSB Action

Lessons From Disaster T. Kletz Reviewed only

What Went Wrong? T. Kletz Reviewed only

Chemical Process Safety, Lessons Learned from Case 

Histories

R. Sanders Reviewed only

Explosions in the Process Industries IChemE Reviewed only

Chemical Reaction Hazards, A Guide to Safety, 2nd Ed. IChemE Reviewed only

NFPA 491 Guide for Hazardous Chemical Reactions NFPA Reviewed only

Proceedings of the 2nd International Symposium on 

Runaway Reactions, Pressure Relief Design, and Effluent 

Handling

CCPS Reviewed only

Occurrence and Impact of Unwanted Chemical 

Reactions, Journal of Loss Prevention in the Process 

Industries 1

B. Rasmussen Reviewed only

Origins of Unwanted Reactions, Report M-2631 B. Rasmussen Reviewed only

Unwanted Chemical Reactions in the Chemical Process 

Industry

B. Rasmussen Reviewed only

Intl. Conference and Workshop on Process Industry 

Incidents

CCPS Reviewed only

Chemical Reaction Hazards and the Risk of Thermal 

Runaway

HSE Reviewed only

Safety of Reactive Chemicals and Pyrotechnics, 

Industrial Safety Series, Volume 5

Yoshida, et al. Reviewed only

Safety and Runaway Reactions Mitchison and Snyeder Reviewed only

Safety of Chemical Batch Reactors and Storage Tanks Benuzzi and Zaldivar Reviewed only
Reactives Hazard Investigation 10-17-02, page 133

APPENDIX F: Statistical Review of Occupational Fatalities

The U.S. Chemical Safety and Hazard Investigation Board (CSB) reviewed Bureau of Labor Statistics 

(BLS) data (1996–2000) on occupational fatalities to determine the significance of the reactive incident 

problem in the context of chemical process safety.68 Table F-1 summarizes this information. 

Table F-1

Review of Occupational Fatalities

Year 1996 1997 1998 1999 2000 Total

Total occupational fatalities 6,112 6,218 6,026 6,023 5,915 30,294

Fatalities in the chemical manufacturing 

industry (a)

40 62 91 78 41 272

Fatalities in the chemical manufacturing 

industry due to fire, explosion, and toxic 

substances (b)

16 23 46 46 16 147

Fatalities from reactive incidents in data 

collected by CSB

2 8 0 10 1 21

Fatalities from reactive incidents in the 

chemical manufacturing industry in data 

collected by CSB

0 3 0 7 (c) 1 11

(a) Chemical manufacturing industry (SIC Division D Group 28).

(b) Incidents that resulted in fires, explosions, and toxic releases are assumed to be process safety incidents.

(c) In addition to occupational fatalities, there was also one public fatality from a reactive incident during 1999. 

 

68 It is important to note that CSB analyzed BLS fatality data only within SIC Division D Group 28 (chemical 

manufacturing and allied products). Thus, the data presented in table F-1 is conservative in that it does not include 

fatalities that occurred to contractors or to personnel in other industries, such as petroleum refining, rubber products, 

paper products. Contractor fatalities are documented within BLS according to the services the contract company 

provides. For example, in the ARCO incidents there were 17 fatalities, 5 ARCO employees (a chemical 

manufacturer under SIC Group 28) and 12 contractors (who had been working at the facility for several years). The

fatalities to the ARCO employees were recorded under SIC Division D Group 28. However, the 12 contractor 

fatalities were not attributed to the chemical manufacturing industry rather they were grouped under the construction 

SIC. Thus, these 12 contractor fatalities would not have been included in our analysis of BLS data.
Reactives Hazard Investigation 10-17-02, page 134

As described in Section 3.1, CSB data represent only a sampling of reactive incidents and should not be 

directly compared to BLS data, which offer a more complete accounting of occupational fatalities. 

Nonetheless, CSB data provide an indication that a significant number of fatalities from process safety 

incidents involve reactive hazards. 
Reactives Hazard Investigation 10-17-02, page 135

APPENDIX G: Identifying Hazards Using Chemical 

Reactivity Testing

This appendix, which briefly illustrates how testing can be an integral part of a reactive hazard 

management system, is provided to facilitate the discussion of alternative criteria for improving 

regulatory coverage in Section 8.0. It does not describe in detail testing methods, theory, or practical 

application. Further information on these topics is provided in Grewer (1994), CCPS (1995a; 1995b), 

IChemE (Barton and Rogers, 1997), and HSE (2000). The Glossary (Appendix A) briefly defines each 

analytical test.

Screening is typically used to indicate when more detailed testing is necessary. The Center for Chemical 

Process Safety (CCPS, 1995b; p. 90) explains that the objective of thermal stability screening is to obtain 

data on the possibility of exothermic (heat generating) reaction for mixtures or self-reaction for single 

substances. Screening calorimeters measure the energy produced by a reaction and the temperature at 

which energy is liberated. Differential screening calorimetry (DSC) is considered to be the primary 

screening test, though differential thermal analysis (DTA) is also used. Thermogravimetric analysis 

(TGA) can also be used to screen for stability at high temperature through precise weight loss 

measurements. 

Screening techniques are relatively cost-effective and require only a small chemical sample; however, 

they do not measure gas evolution or maximum pressure rise. A material is generally considered to be 

thermally stable if the temperature at which energy from reaction is first observed is at least 100 degrees 

Celsius (oC) above the maximum operating temperature of a process event under upset conditions (CCPS; 

1995b; p. 93).

CCPS (1995b; p. 94) recommends more sensitive and sophisticated methods if screening calorimetry 
Reactives Hazard Investigation 10-17-02, page 136

shows thermal instability at or near the temperature range of large-scale storage or processing. The next 

logical choice is adiabatic calorimetry,69 which uses a larger sample and more advanced technology. This 

technique is more sensitive to detecting the onset temperature70 for exothermic reactions, adiabatic 

temperature rise, and rate of reaction; it also can measure pressure rise in a closed vessel, an important 

parameter in reaction scaleup. Compared to screening calorimetery, this sophisticated technique more 

accurately measures the overall energy of reaction, though the tests tend to be more costly and time 

intensive. 

A common theme of industry guidelines is that every test result must be individually interpreted because 

of limitations and variations in conditions, and the complexity of the instrument. Factors such as sample 

size, container material, and heating rate can greatly affect results. Therefore, personnel with appropriate 

training and experience should be consulted both before testing and for interpretation of results. 

CCPS offers guidance on when to conduct testing for hazard identification. CCPS (1995a; p. 13) 

suggests that when designing processes for conducting chemical reactions, all materials should be subject 

to screening tests even if no reactivity concerns are identified in the literature search or by expert 

judgment. In other guidance, CCPS (1995b; p. 85) states that that prior experience, theoretical 

evaluations, and expert opinion may be used to determine whether screening tests are necessary in 

designing storage and handling systems for reactive materials. 

One of the factors that may be important in this determination is the possible rate of reaction. Theoretical 

evaluations can determine a large potential energy of reaction, but they do not determine how fast or slow 

that energy can be released. The rate of reaction can be the critical factor in determining the severity of 

 

69 In this context, the term “adiabatic” refers to calorimetry conducted under conditions that minimize heat losses to 

the surrounding environment to better simulate conditions in the plant, where bulk quantities of stored or processed 

material tend to minimize cooling effects. This class of calorimetry includes the accelerating rate calorimeter 

(ARC), from Arthur D. Little, Inc., and PHI-TEC from Hazard Evaluation Laboratory Ltd.

70 Onset temperature is the lowest temperature at which the test first observes an exothermic (heat liberating) 

reaction.
Reactives Hazard Investigation 10-17-02, page 137

the reactive hazard (CCPS, 1995b; p. 86). When such uncertainties arise, an expert opinion may be 

needed to determine whether chemical testing is necessary. 

Five of nine respondents to the CSB survey frequently use both screening and more sophisticated 

approaches, including adiabatic calorimetry, to determine the thermal stability or compatibility of process 

materials. Seven of nine respondents use screening alone for chemical reactivity testing. The most often 

used testing objectives are:

• To determine the onset temperature of a runaway reaction using calorimetry.

• To determine thermal stability using screening tests.

• To determine gas evolution and maximum pressure rise.