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Workplace Accident Investigations: The Definitive Guide

Workplace Accident Investigations: The Definitive Guide

When conducting workplace accident investigations, take these steps to correct the situation and prevent similar incidents in the future.

Every seven seconds, an employee is injured on the job. That adds up to 4.6 million workplace accidents in the US every year.

One way employers can cut this number down is to conduct thorough, timely accident investigations. Finding out the root cause and taking corrective action can keep one workplace accident from turning into dozens. Use our step-by-step guide to workplace accident investigations to help you prevent injuries on the job.

Don't miss any essential steps. Keep our workplace incident investigation checklist handy to ensure your investigation goes smoothly.


What is a Workplace Accident?

A workplace accident is "a discrete occurrence in the course of work which leads to physical or mental harm." Accidents may cause harm to workers and witnesses, but also damage to the employer's property.

A near miss, or a workplace incident that could potentially cause harm but didn't, should be taken just as seriously as a harmful accident. For instance, if a box fell from a shelf and barely missed a worker's head, you should conduct an investigation to reduce the risk of a serious accident in the future.

Employers should be extra vigilant about the three injury events that result in the most lost work days:

  • overexertion (e.g. heavy lifting, repetitive motions)
  • contact with objects and equipment (e.g. worker struck by, caught in or compressed by objects or equipment)
  • slips, trips and falls (e.g. falls on the same level, falls to a lower level)

RELATED: The Complete Guide to Workplace Incident Investigations

Workplace Accident Causes

The primary goal of accident investigations is to find the root cause. An accident may result from one of the following causation categories or from a combination of a few.


A task-related root cause involves the actual work the employee was doing. Did they follow standard work procedures? Had work conditions changed in a way that made the normal procedures unsafe? Did the worker use the proper tools or equipment for the job? Were safety devices working correctly?

Example: A construction worker building a house jumps from one level to another instead of climbing down a ladder and sprains his ankle.


A material-related accident is caused when equipment or materials are faulty or dangerous. Did a piece of equipment fail? If yes, why? Is the equipment poorly designed or outdated? Were hazardous substances involved in the accident and were they clearly marked? Should personal protective equipment (PPE) have been used? If so, was it used and used properly?

Example: A shelf collapses and heavy objects fall onto a worker, crushing her foot.


The physical work environment and changes to it could also cause an accident. What were the weather conditions at the time of the accident? Was it noisy? Were toxic fumes, dusts or gases in the air? Did the work area have excessive clutter? Was it too hot or cold? Did the workspace have adequate light?

Example: A workspace is poorly lit, causing a worker to trip over an electrical cord she couldn't see. As a result, she sprains her ankle.


Sometimes an accident's root cause comes from the employee's education, experience, or physical or mental condition. Was the worker experienced or at least adequately trained in the work they were doing? Were they physically capable of doing the task? Did they feel sick, tired or stressed out?

Example: An employee is tasked with lifting objects that are too heavy for them, resulting in a serious back strain.


Finally, management systems and styles may lead to workplace accidents. Did the employee's manager communicate safety rules to them? Were procedures written down and enforced? Was the employee trained to do their specific tasks? Was adequate supervision provided? Did management perform regular equipment maintenance and inspections?

Example: An employee's manager does not inform him that employees must wear eye protection when entering a certain area. When the employee enters this area alone later, metal shavings fly into his eye, causing permanent blindness.

Workplace Accident Investigations - Step by Step

When a workplace incident occurs, gather a knowledgeable team to conduct the accident investigation. Your health and safety committee, as well as employees who have experience in the work the injured party was performing, should be part of the investigation. If possible, include the employee's supervisor.

Not all workplace accidents result in an injury or property damage. Use our near miss reporting form to log these.

1. Administer First Aid

Employee safety should be your number-one priority, so always start by administering first aid. You can address smaller injuries like scrapes or splinters in the workplace with a first aid kit. For more serious accidents, call 911 to get the employee the medical attention they need.

The only exception to this is if administering first aid would put you or the injured person in danger. For instance, if a worker is trapped in a confined space, trying to enter the area puts you at risk. Instead, wait for emergency workers to arrive.

2. Secure the Scene

Next, secure the scene of the accident. Clear other employees from the area and rope it off. If possible, remove sources of immediate danger (e.g. put out a fire or turn off a machine). Try to keep the scene as intact as possible to ensure an accurate investigation. While providing medical care and removing imminent hazards may disturb the scene, minimize their effects when you can.

If the employee is killed or critically injured on the job, file a report with the Occupational Safety and Health Administration (OSHA), your union (if applicable), your workplace's health and safety committee and the local police as soon as possible.

RELATED: Top 10 Ways to Prevent Workplace Accidents

3. Collect Evidence

Perform this step as soon as you can after the incident. The less time that passes before you start the accident investigation, the easier it is to observe the scene's conditions as they were at the time of the accident.

Collect physical evidence that may help you uncover the accident's root cause. Record the scene visually using video or still photos. Study the conditions and environment. Finally, take copious notes so you don't forget any details. Remember that fact-finding, not fault-finding, is your goal.

If you use a case management system to log your workplace accident investigations, you'll spend more time analyzing and less time filing paperwork. You can keep all the relevant information, photos, evidence and supporting documents right in the case file. Not having to search for the data you need ensures you can correct and prevent hazards faster.

4. Conduct Interviews

In addition to collecting evidence, you should also identify witnesses. Interviewing witnesses provides insight into the accident that may not be apparent during your physical investigation. While you also need to interview the injured employee, they may feel too shaken up to provide accurate information right away.

When interviewing witnesses, ask questions such as:

  • What did you witness?
  • What was the date and time of the accident?
  • Where exactly did it happen?
  • Do you know the cause of the accident?
  • What was the person doing at the time of the accident? What were they supposed to be doing?
  • Have you seen a similar accident happen before? If so, how often?
  • Who else witnessed the accident?
  • Was the employee trained and/or experienced doing the task they were performing?
  • What tools, equipment or machinery was the worker using?
  • Is any PPE required for this task? Was the worker using this PPE?
  • When was the last time the supervisor checked on the work area?

5. Identify the Root Cause

The primary goal of every workplace accident investigation is to find the root cause. If you know what led to the accident, you can prevent it from happening again. Keep in mind that the accident may have multiple causes. For instance, an employee was not properly trained and was working with hazardous substances.

Root causes must be:

  • specific underlying causes
  • reasonably identified (don't take up too much time to identify)
  • under management's control
  • able to have effective recommendations generated to prevent them from recurring

To perform a root cause analysis, investigative teams should start with data collection, then create a chart of causal factors by analyzing the details of the accident. A causal factor chart is a sequence diagram that describes the events leading up to an accident, plus the conditions surrounding these events, allowing investigators to determine the root causes.

Learn about different tools you can use to perform a root cause analysis to get to the bottom of the problem with our free cheat sheet.

6. Prepare an Investigation Report

During the accident investigation you've collected evidence, interviewed involved parties and analyzed that information to find the incident's root cause. Now you have to communicate it all to management.

If the thought of creating a final report fills you with dread, use case management software with one-click reporting capabilities. This gathers data from the accident's case file, compiles it into a pre-formatted template and creates an easily sharable, professional report with one click. Request a demo to see this feature in action here.

Download our workplace accident investigation report template to ensure you record and report on all the key details.

7. Recommend and Implement a Corrective and Preventive Action (CAPA) Plan

Your final accident investigation report should include recommendations to prevent future incidents. Develop a Corrective and Preventive Action (CAPA) plan for management to implement that will mitigate risk. Your plan should consider the accident's root cause and include concrete steps to take that will address it.

Corrective actions are immediate fixes to the accident's causes. These could include replacing a faulty piece of equipment, giving the employee better training or changing their work tasks.

On the other hand, preventive actions avert similar accidents in the future. Examples might be reviewing and changing your health and safety procedures, scheduling more regular equipment inspections or making PPE mandatory.

8. Follow Up

Even the strongest CAPA plan won't prevent workplace accidents if it isn't enforced. Follow up with the recommendations after a few weeks, then a few months to ensure they're being implemented. If the changes don't seem to be making a difference, consider revising the CAPA plan and its timeline to maximize results.


How do you investigate accidents in the workplace?

To investigate accidents in the workplace, you need to follow a step-by-step process, which includes administering medical care, securing the scene, collecting evidence, conducting interviews, identifying the root cause, preparing an investigation report, implementing a Corrective and Preventive Action (CAPA) plan, and following up on the recommendations.

What workplace incidents must be investigated?

Workplace incidents that must be investigated include accidents causing physical or mental harm to workers, damage to employer's property, and near misses, which are incidents that could potentially cause harm but did not.

What are the 5 key questions to ask in accident investigations?

The 5 key questions to ask in accident investigations are:

  1. What did you witness?
  2. What was the date and time of the accident?
  3. Where exactly did it happen?
  4. Do you know the cause of the accident?
  5. What tools, equipment, or machinery was the worker using?