Asking questions after an incident involving hazardous chemicals

Apr 29, 2019 Posted by Walter Ingles

Incidents involving hazardous chemicals open up a whole range of questions: what really happened? Why? Who? How? This blog is all about asking questions — not just the questions to ask, but better ways to ask them. Use this blog as you create your own checklist of questions to use during your HAZCHEM incident investigation.

REMEMBER: The scene of an incident involving hazardous chemicals may still contain spilled fuel, smoke, fumes, dusts, and other chemical residues. Keeping people safe and securing the incident site should always be prioritised over asking questions and beginning the investigation.

Questions at the scene of the incident

The first questions in your investigation will arise as you appraise the scene of the incident and gather physical evidence. These questions drive your efforts to piece together what happened and aren’t necessarily asked to another person. You will be considering:

  • Which people were directly involved in the incident?
  • Were there other workers or bystanders not directly involved who witnessed the incident?
  • Who needs to complete an incident report?
  • What machinery, tools, or equipment was being used at the time of the incident?
  • Do any of these items look damaged, broken, substandard, or defective?
  • Did any of these items fail?
  • What hazardous chemicals were involved?
  • Is the Register of Hazardous Chemicals accessible and up-to-date?
  • Were chemicals labelled and stored correctly?
  • Are there any incompatible chemicals/materials still in the area?
  • What is the condition of chemical containers?
  • What PPE or safety device was being used at the time?
  • Was the PPE suited to the job or task?
  • Did the PPE or safety equipment fail in any way?
  • Were there any makeshift tools or implements being used?
  • What is the state of housekeeping at the scene?
  • How does the scene look from different angles of the worksite?
  • Where was the sun shining at the time?
  • Was the workplace in lockdown or fully operational?
  • Were any of the workers in a restricted area without clearance?

REMEMBER: This list of questions is not intended to be exhaustive, but to open up ideas for your own checklist.

Questions for witnesses

As your investigation continues you’ll be talking to witnesses, and focusing your enquiries around ‘what caused the incident’ rather than ‘who is to blame’. Before conducting an interview you should have read the incident report already completed by the witness. And possibly revised the testimony of other people you have spoken to.


Need to run a full investigation?  Take a look at our blog post on how to run an effective hazchem incident investigation in 4 steps.


Background questions

Begin your interview with a series of background questions to set the context of how the witness were involved in the incident. These questions should be broad in scope allowing the witness to initially relay their version of the incident without interruption. You could simply begin with:

  • Can you explain what happened on the day of the incident: what you were doing, what you saw, and how you were involved? Please start at the time you commenced your shift, right through the actual incident including the emergency response, site shutdown and evacuation.

Getting to specifics

Once you have allowed them to describe their version of the incident, you can begin to get more specific about what happened, and why? Questions like:

  • Where were you at the time of the incident?
  • Can you show me exactly where you were standing, sitting, squatting?
  • What actual job procedure were you carrying out at the time?
  • Can you recreate what you were doing?
  • What instructions had you received from your supervisor?
  • What chemicals or Dangerous Goods were you using at the time?
  • Were you doing anything differently to standard procedure? If you were, then why?
  • Were you using any PPE at the time? If so, what condition was it in?
  • Can you outline any specifics about workplace conditions that day?
    • What was the weather doing that day?
    • How was the lighting?
    • What was the state of housekeeping?
    • Was it extra noisy that day? What could you hear?
    • Was there smoke? Could you smell chemicals while you worked?
  • What happened once the worker was injured?
  • Was there any problems giving assistance (eg, first aid kits fully stocked, SDS missing)?
  • Did you know what to do during the site evacuation?

Leading questions

When asking questions to confirm specifics, you might find yourself using a lot of leading questions. Leading questions suggest an answer to the witness, and should be avoided. Here’s a couple of examples.

Leading question Possible re-frame

Were you wearing your thermal protection gloves when you changed the LPG cylinder?

What were you wearing when you changed the LPG cylinder?

So you were wearing the latex gloves that your supervisor handed to you before diluting the hydrofluoric acid?

Where did you get the latex gloves you used when diluting the acid?


Reframing ‘blame’ focused questions?

Sometimes in our quest to find the truth, the questions we choose are based on efficiency. Whilst practical in nature, they can be perceived as insensitive and ‘blame-focused’. The real problem is that people can become guarded if they think they are going to get into trouble, so they often limit their answers instead of opening up. Let’s consider the following real-world example:

A laboratory worker was wearing latex gloves while diluting hydrofluoric acid. The gloves were defective and some of the acid contacted their fingers. The worker ignored the injury, but two days later (in severe pain),  reported the injury. Because the acid had already penetrated the skin, the worker’s fingers were permanently damaged.

You want to open a line of questioning to find out why the worker was using defective gloves and the reasons for not reporting the incident. In this real-world example the worker actually didn’t understand the properties of the acid and didn’t understand the severity of their injury. But if you ask questions that make the worker feel threatened, or foolish  you may never get to that truth.

Here’s a few examples for consideration:

Blame-focused question Possible re-frame

Why did you use those gloves instead of the chemical resistant gloves that were available?

Did you know that chemical resistant gloves were available for this procedure?

Who else has been using those gloves?

Is it common practice to use latex gloves for this procedure?

Why don’t you know how to use the safety shower?

Have you ever used the safety shower before? When was the last time you turned it on or used it?

Haven’t you had any training?

Have you used this chemical before? Can you show me the Safety Data Sheet for this chemical? When was the last time you received training? You might also check training records before following this line of questioning.

Why didn’t you report the injury immediately?

Were you in pain when the acid leaked onto your fingers? Was there a reason you didn’t tell your supervisor this happened?

Where was your supervisor while all this was happening?

Was your supervisor working in the lab that day?

  • REMEMBER: Blame-focused questions appear like you already have a notion of what happened and who is at fault. Workers can easily pick up on this and help follow a line of questioning that shifts the blame to someone else.

Questions for the evaluation team

Finally the evaluation team will be asking bigger picture questions to establish which systems failed, and what processes could be implemented to prevent recurrences. Here are some examples to use as a starting point:

  • What system failed?
  • Why do we use this system?
  • What does this system specifically achieve?
  • Do we still need to do this?
  • What could we do instead?
  • Is there another way we could do this?
  • Would it make a difference if we did this at a different time?
  • Would it be more effective to do this in a different location?
  • Are there any triggers that could alert us to an impending system failure?
  • Is there a chemical hazard here that was missed in our last risk assessment?

Next steps

The questions you ask during a HAZCHEM incident investigation will always vary according to the chemicals being used at the time, and the severity of the incident. Our blog is intended to get you thinking about the questions you ask, and how you ask them. For a more detailed look at the incident investigation process why not download our free eBook Key steps in a HAZCHEM incident investigation. Read it today for another step in HAZCHEM safety.

Key Steps in a HAZCHEM Incident Investigation

Walter Ingles

Walter Ingles Compliance Specialist

Walter is STOREMASTA’s Dangerous Goods Storage Specialist. He helps organisations reduce risk and improve efficiencies in the storage and management of dangerous goods and hazardous chemicals.

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