Including health hazards and physical hazards in your chemical risk assessment

Mar 16, 2020 Posted by Walter Ingles

When carrying out a risk assessment at your workplace it’s essential that you recognise both the health hazards as well as the physical hazards presented by the chemicals you use, store and handle. This blog takes a deep dive into chemical hazards and the key differences in the way these risks are assessed. Hazardous chemicals can be extremely complex as the way they are stored and handled often contributes to the hazards.

Assessing Chemical health hazards

When assessing chemical health hazards the main consideration is understanding the different situations where people could come into contact with the chemicals. You need to identify which of your workers is potentially at risk (plus other contractors, visitors or customers) and the extent of the exposure.

You will need to take into consideration:

  • Physical form and concentration of the substance (eg, liquid solvent 60% Toluene)

  • How the chemical could get into the body and affect human health (eg, inhalation)

  • The chemical and physical makeup of the substance (eg, toxicology)

  • Duration of exposure (eg, length of shift)

  • Other chemicals being used (eg, chlorine and ammonia together can create a toxic gas)

  • Individual health factors (eg, age, weight, allergies of individual workers)

REMEMBER: When chemicals are a health hazard they are often toxic to animals, plants, fish, and the environment. You’ll also need to consider this in your risk assessment.

Physical hazards

A chemical is a physical hazard if the chemical can burn (or support a fire), explode, or react dangerously (by itself or) when in contact with another substance. While chemical health hazards are primarily assessed on how they will impact human workers, physical hazards are assessed by how they are impacted by other materials and ignition sources. Let’s take a look at each of them below.

Fire hazards

When a chemical is identified as flammable, combustible or an oxidiser you’ll need to assess how the chemical could create a fire. This will include identifying and considering:

  • Flashpoint of flammable liquids

  • Location of existing chemical stores (are they away from heat, ignition sources, combustibles, vegetation, refuse and hazardous waste)

  • Correct segregation of Dangerous Goods by hazard class

  • Work practices and machines that generate heat, sparks, require a naked flame/burner

Explosion hazards

For explosion hazards, identify whether the explosive is an unstable material that can detonate, or a compressed gas. You’ll need to know the ways an explosion could occur:

  • Decomposition after a dropping a cylinder

  • The  detonation of nitroglycerine and TNT

Reactive hazards

When using or storing reactive chemicals you’ll need to know how they could react and the consequences of the reaction. This will include:

  • Temperatures, climate or conditions that could cause a spontaneous reaction

  • Incompatible substances or materials

Handling and storage hazards

Chemical hazards can be increased (or even created) through incorrect handling, poor housekeeping, and storage. A worker falls over while carrying an acetylene cylinder, a container of acid left on a benchtop, a worker mixing paint and solvent drops the tin, a gas bottle left unchained in the workshop: your risk assessment should evaluate your operating procedures, staff training program, and overall supervision.

Here are some handling and storage hazards to consider in your risk assessment:

Manual handling

  • Dropping gas cylinders over the side of a truck or rolling them along the ground

  • Attempting to carry gas bottles by the valve or cap instead of using a mechanical lifting device/trolley

  • Trying to manoeuvre or carry heavy chemical drums

  • Carrying chemicals in a glass (or other breakable container) and an unexpected door opening knocks the container from the hands of a worker

Decanting packaged chemicals

  • Pouring chemicals from larger containers into smaller containers by hand

  • Decanting chemicals into unlabelled containers

  • Mixing and measuring of chemicals carried out by an experienced or untrained worker

Chemical Storage

  • Stacking cardboard cartons of aerosol cans without anything to protect the stacks from collapsing

  • Leaving gas cylinders free-standing without restraining them with a strap or safety chain

  • Storing empty and full gas cylinders in the same area

  • Segregating chemicals incorrectly and allowing incompatible substances and materials to be stored together eg, storing acids and alkalis together


  • Leaving open containers of chemicals on sinks or benchtops

  • Failing to train (or adequately supervise) workers to only use chemicals for their intended purpose eg, using solvents as hand cleaner, using petrol to wipe down benchtops or equipment, using oxygen as a substitute for compressed air

  • Allowing staff to handle chemicals and then eat/smoke/take a break without washing hands or changing out of protective clothing

Housekeeping, storage, and handling hazards are generally created because staff don’t follow procedures, haven’t been trained properly, or don’t have sufficient supervision. All of this needs to be factored into your chemical risk assessment.

Next Steps

Now you know how to approach a risk assessment of both chemical health hazards and physiochemical hazards why not download our free eBook How to manage the risk of Hazardous Chemicals in the workplace to make sure nothing gets missed at your workplace. You’ll learn how a risk assessment fits into a compliant risk management plan and gain access to useful WHS tools including the Risk Management Matrix Template. Download and read it today.

How to manage the risk of hazardous chemicals in the workplace

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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