Components of Fires, Explosions, or Chemical Releases

Natural gas, petroleum oil or hydrocarbons including gasoline, diesel, heating oil, and jet fuel, LNG, LPG, coal, ethanol biofuels, chemicals, fertilizers, reactive gases, metals, electrical systems, equipment, and warehousing activities may be components of industrial or utility fires, explosions, or chemical releases.

The Importance of the Site Inspection

After a fire, explosion, or chemical release, a site inspection by a qualified expert witness enables counsel to effectively represent the interests of clients be it plaintiff or defense. The site inspection helps build a solid foundation to determine and substantiate the liability and responsibility for the incident, the resulting damages, and restitution. It may also provide information about potential punitive, and/or criminal consequences. Failure to perform an effective and very credible site inspection can adversely impact the subsequent litigation.

A well-planned site inspection by a Certified Fire & Explosion Investigator (CFEI) enables scientific analysis of the event and facilitates gathering and preservation of critical evidence. Using data analysis and sound methodology, a CFEI utilizes critical knowledge and determines to the best scientific degree possible, the physical dynamics of the event.

The site inspection should strive for diligent scientific and engineering analysis, and performance of the scientific method independent of other parties, be they private individuals or authorities, such as the OSHA (Occupational Safety & Health Administration) and the CSB (Chemical Safety Board).


As described by the National Fire Protection Association (NFPA) in publication 921 Guide for Fire and Explosion Investigations 2017 in its Application, “This document is designed to produce a systematic, working framework or outline by which effective fire and explosion investigation and origin and cause analysis can be accomplished.”[i]

Goals, Expectations, and Benefits of an Effective Site Investigation

The first expectation of an effective site inspection is that the F&EI expert will “Assess the Scene” by asking questions and noting observations.

  • Was the site secured?
  • Did spoliation of evidence occur?
  • Documenting observations and first impressions.
  • The noting of pressure waves and effects.
  • Determining release of emissions including particulate, chemicals, combustion and explosion by products.

The second expectation of an effective site inspection is the collection of physical evidence–searching for ALL forms of:

  • Fuels and combustible materials
  • Oxidants including air and oxidizing chemicals
  • Ignition and ignition sources
  • A sustaining mechanism for the oxidation

And physical evidence sampling, including:

  • Sampling method
  • Preservation of samples
  • Preservation of chain of custody
  • Time until analysis is performed (sample integrity, degradation)

Thirdly, it’s important that an effective SI include a plan for collection of technical evidence, such as:

  • Process equipment
  • Instrumentation & measurement systems
  • Electronic data recording
  • Manually-written operator logs

Witness Statements

The SI should include accurate witness statements and other relevant information to include:

  • Site drawings
  • Design documents for building structures and equipment
  • Videos and images of the event as recorded
  • Site reconstruction if feasible


The F&EI expert will also independently analyze all evidence and information utilizing the scientific method, including activities such as:

  • Evaluation of potential possibilities and theories of ignition, propagation, and flame spread
  • Root cause of the event and energy progression
  • Physical impressions/indentations and pressure waves
  • Fluid mechanics and heat transfer
  • Resulting injuries/impacts to personnel and human life
  • Resulting damages and losses to property
  • Environmental impacts, exposures and risk assessment
  • Primary vs secondary or consequential effects


An incomplete site inspection by an oil and gas expert witness can lead to more questions than answers and can weaken the representation of the client’s interests. A comprehensive site investigation should not “cut corners” or be quickly completed as collection of the evidence is the foundation for the client. Results and interpretations may differ, and uncertainties in the analysis can result in as many different opinions as there are number of investigators on the site. Conversely, an effective site investigation provides an accurate and fair representation of the client’s interests.

About the Author

John A Williams, PhD, PE, CFEI, MBA, ASA, AIChE Fellow is an energy technology expert witness, fire & explosion investigator, and appraiser for EPS. Dr. Williams performs technology assessments, forensic investigations, and financial appraisals in oil & gas production, oil refining, power generation (boilers, steam, turbines, electricity production), fuels (gas, oil, coal, biomass), chemicals, plastics, steelmaking, glassmaking, biotechnology and renewable energy (waste-to-energy, gasification, biofuels, ethanol, cellulosics, wind, solar) facilities. Forensic investigation expertise includes fires, explosions, chemical releases, dust, industrial accidents, and equipment failures. A licensed Professional Engineer, Dr. Williams has over 39 years of engineering experience and has led EPS a full-service engineering firm for 25 years. Dr. Williams has been elected a Fellow of the Institute of Chemical Engineers (AIChE) and has been an Instructor for the AIChE since 1996. Dr. Williams is Certified Fire & Explosion Investigator (CFEI) by the National Association of Fire Investigators (NAFI) and an Accredited Senior Appraiser by the American Society of Appraisers (ASA).