What is a HAZOP study? (Plus how to implement one at work)

By Indeed Editorial Team

Published 18 July 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Workplaces rely on various methods to identify and assess hazards. A hazard and operability study (HAZOP) is one such risk assessment method businesses can use to minimise hazards and prevent the likelihood of damage or injury occurring. Knowing what HAZOP is and how to use it can help you implement more stringent safety measures in the workplace. In this article, we discuss the concept of HAZOP and its components, explain the benefits of using it and offer some tips on implementing the system at work.

Related: Guide to risk assessment (with a risk assessment template)

What is HAZOP?

HAZOP is an acronym that means 'hazard and operability study'. It's a method that business leaders use to analyse hazards in workplaces and implement risk management protocols. The technique involves studying new and existing processes, operations and policies to determine what potential risks may arise. In the UK, the law states that it's important for risk assessments to be 'suitable and sufficient'. A health and safety executive is responsible for ensuring businesses comply with their standards, which vary by industry. When reviewing HAZOP methods, the following definitions are helpful to know:


Hazards can potentially cause harm and typically emerge in the workplace when deviations from the norm occur within business processes. It's important to prevent hazards from harming property and staff, so businesses use HAZOP methods to deal with them. HAZOP studies focus primarily on threats in terms of how to identify them and how to implement systems to uncover and mitigate the risks they can produce.

Related: What is a risk management framework? A comprehensive guide


Harm can result from unchecked hazards. Property damage, injuries to people and environmental damage are all forms of harm. Unidentified hazards can create risks for employees and businesses.


Risk is the probability of a person, environment or property suffering from harm because of an unchecked hazard. Hazards are one of the primary areas of focus in HAZOP studies, but they rarely calculate the likelihood of injury occurring. Instead, they identify which hazards can create risks. For example, if a business operates a furnace and there is a chance that the equipment can burn people, this is a hazard because it has the potential to cause harm and damage.

Related: How to become a health and safety inspector in 6 steps


These are the normal conditions in which a process operates. Safety experts use parameters in their assessments because they offer a tangible way to understand when businesses are operating safely or if they are at risk. The following are some typical parameters:

  • pressure

  • level

  • flow

  • speed

  • shutdown

  • reaction

  • operation

  • temperature

  • composition

  • maintenance

  • information

  • time

For example, a power plant may use equipment set at a particular temperature and pressure to move chemicals around the building. In that case, such parameters are important to the operation of the plant. As a result, these aspects may be an area of focus during a HAZOP study.


Deviations occur when people and equipment don't behave according to the standard parameters. Multiple factors can cause deviations, such as equipment failures, human error or environmental problems. This is an important aspect of these analyses because variation can produce hazards and risks.

Using the power plant example, if a safety expert notices a leaking pipe, this may cause a deviation in the machine's pressure. They then record the leaking pipe as a deviation that can be hazardous to the business and its employees.

Related: What is a risk rating and how do risk assessments use them?

Benefits of using a HAZOP study

HAZOP studies are beneficial for businesses by helping them identify potential hazards in equipment, processes, facilities and individual projects. The studies are also helpful for exposing risks relating to staff behaviour and performance at work. Businesses can reduce the risk of workplace injuries by analysing study results, increasing employee awareness of risks and showing how to mitigate them. In addition, risk management teams can implement new safety measures to keep the business and staff safe by identifying hazards.

Related: The importance of health and safety at work (with tips)

How to implement HAZOP in a business

Here are some steps you can follow to successfully implement the new initiative:

1. Create a HAZOP team

When building an effective HAZOP team, it's helpful to incorporate members from various professional backgrounds. This includes members with training in maintenance, engineering, operations and process design. Other professionals may also be useful depending on the environment of the HAZOP study. Professionals with previous experience using HAZOP can be particularly effective at identifying deviations.

2. Identify elements and parameters

To create a workplace HAZOP plan, professionals first identify all the steps in the business's operations and their standard operating parameters. This is necessary to determine potential hazards and how they may arise. Here are some examples of parameters for a company that manufactures cat toys:

  • the temperature of the molten plastic the machine injects into toy moulds

  • the volume of material per mould

  • the speed of the production machines as they operate

  • the environmental conditions in the room, such as humidity levels

  • the type of material to produce the cat toys

3. Describe potential deviations

The next stage is to consider all possible deviations from the routine parameters of workplace processes to identify potential hazards. Imagine a shift from these parameters and consider the result. For example, if a machine that manufactures cat toys operates at a certain speed and the speed suddenly changes, the deviation may disrupt production and create a risk. A HAZOP team identifying the problem can note the variation and evaluate the risk.

4. Identify hazards and potential problems

After identifying deviations, decide what potential hazards may occur and consider their impact. If the effect constitutes a hazard, make a note. It's important to uncover potential hazards to lower risks. Using the example of the cat toy production machines, contemplate what might happen if the machine began operating at a higher speed. This may lead to an overheating risk resulting in burns to employees' skin or a fire outbreak. So, for the deviation of an increase in machine speed, these are the associated hazards.

5. Review HAZOP results and evaluate safety protocols

Following the completion of the study, professionals can analyse the results and suggest how to address safety concerns and promote a safe workplace. This helps to reduce the chance of accidents or business disruptions due to hazards. In addition, these suggestions can promote new hazard-prevention measures and safety protocols. To illustrate, if a machine in a cat toy factory is prone to overheating, a risk assessment expert may suggest close supervision of the device, noting any deviations from the standard operation, and more frequent maintenance checks.

Related: Health and safety responsibilities for employees (with tips)

4 tips to effectively implement HAZOP

Consider the following tips when implementing a HAZOP study in the workplace:

Identify the objectives of the study

Most HAZOP studies have similar objectives, but some may differ due to the type of facility in which they occur. Here are a few example objectives for HAZOP studies:

  • Document all potential hazards.

  • Evaluate how safe operations are within a facility.

  • Identify any operational or environmental concerns.

  • Identify problems that may hinder the facility from its standard productivity levels.

  • Make recommendations on how to eliminate hazards or reduce the risk of hazardous materials.

Prepare and plan

It's important to plan the requirements of a HAZOP study to develop a system that effectively analyses potential hazards and risks. While planning this study, review the following:

  • Determine the best way to record data specific to the study.

  • Determine how much time a study may take.

  • Gather all documents from the facility regarding their current performance standards, management policies, operation and maintenance guidelines.

  • Obtain diagrams of the facility and its processes.

  • Ask for and review previous HAZOP reports from the facility.

  • Choose guide words to use during the study.

  • Identify the process parameters.

Identify deviations and potential causes

Looking at the various process parameters and deciding how best to categorise them is a handy way to uncover deviations and identify the cause of potential threats at work. Doing so helps risk assessors devise safety measures to prevent hazards from causing harm and disruption. For example:

  • low + temperature = low temperature

Here, the guide word is 'low', and the process parameter is 'temperature'. Using a guide word along with the parameter enables professionals to identify 'low temperature' as a deviation.

Related: How to perform a risk analysis (with tips)

Produce documentation of the study

When completing a hazard report, it's important to document all aspects of the examination and risk assessment and to include the assessor's conclusion. Professional assessors ensure proper measures are in place to mitigate potential risks and threats. They also advise on how to mitigate hazards and reduce risks if no safety measures exist.

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