How to Assess, Analyse and Control Chemical Hazards

Hazardous chemicals are chemicals that present physical or chemical hazards. Chemicals can react in a way that results in a fire, explosion or toxic gas release. These reactions can cause serious harm to both human and property if handled or stored inappropriately. All chemical materials can be hazardous to health under the wrong conditions such as inappropriate handling and storage. To be able to assess, analyse and control these chemical hazards, you need to understand the characteristics of the chemical and the factors under which they can cause ill health such as:

  1. the chemicals’ form (that is solid, liquid or gas – solids like metal and treated wood, liquids like ethanol, mists/liquid droplets sprayed into the air e.g aerosols, and gas such as vapor from heated substances or ultraviolet radiation. Chemical hazards can also be in form of dust and fibre particles such as asbestos and wooddust)
  2. how the chemical makes contact with the body (ingested, inhaled, absorped or injected into the body. They can be ingested through eating or drinking, inhaled through breathing it in, absorbed through the skin, eyes or other membranes and injected – that is, entry via a puncture or wound);
  3. the amount of chemical the body receives; and
  4. the toxicity of the chemical (that is, how poisonous the chemical is).

The first step is to assess the chemical hazard by inspecting the workplace for chemcials present and checking the records. While inspecting, you need to make a note or list of all the hazardous chemicals.

The next step will be the analysing each chemical to undertand the hazards they present. To achieve this, you need to get the material safety data sheet (MSDS) for each chemical. Obtaining the MSDS will provide you with the hazards presented by each chemical and will help you determine the 4 factors listed above. You must then prepare a detailed assessment report which should be accessible to all parties involved. Don’t forget to include preventive/control measures in your report (information on control has been provided below). There is no point telling employees what hazards they face without you providing them with knowledge on how to protect themselves.

Controlling chemical hazards.
No matter how hazardous a substance is, it can be used safely as long as adequate control measures have been put in place to prevent exposure to the chemicals. Many of you must have heard of “Hierarchy of Controls” and are quite familiar with them. However, I have heard of instances where in the NEBOSH exam, people have mistaken it for organisational hierarchy and written Director, Manager, etc. A friend of mine marks NEBOSH questions and he has seen this a few times. So for the sake of those who haven’t heard of Hierarchy of Controls or haven’t fully grasped its concept, I will try my best to demystify it.

There are 5 strategies/levels in the Hierarchy of Controls. You have to start with –

  1. Elimination. This is the best solution. You need to get rid of all potentially hazardous substances.
  2. Substitution. If it is impossible to get rid of all hazardous substances, then the next step should be you replacing a toxic substance with a less toxic substance. For example, instead of using the usual cleaning product, you should substitute it for biodegradables which are non-toxic and “green”.
  3. Engineering controls. This is used to control the hazard at source. Where substitution might not be ideal, you could use engineering controls as they control the hazard at source and reduce or even eliminate exposure to the chemical hazard. It is always best to use total enclosure if engineering control is the best option for you.
  4. Administrative controls. This involves using changes in work procedures and policies to reduce the time of exposure, the frequency and the severity of exposure to the hazards. This method does not eliminate the chemical hazard but rather introduces safer work procedures through policies, supervision, information and training. Despite all this, the method might not be as effective as the first 3 – this is because the success of administrative method depends highly on the employees as they have to obey the policies and use the information provided for the method to work. Regular supervision, recognition and rewards will help.
  5. Personal Protective Equipment (PPE). This is the most common method used today. PPE provides a barrier between the worker and the hazard. As in administrative controls, the hazards aren’t eliminated or reduced so high success with this method is dependent on appropriate use of the PPE.

You see that the first 3 methods requires you to do something while the last 2 requires you behave appropriately to reduce exposure to hazards. Ideally, the use of PPE should be the last resort but many never bother with the other methods and head straight for protective equipment. Before deciding to use PPE, you must carry out a risk assessment to determine the best control measure needed.

Confused about MSDS? Watch out for my next post on understanding material safety data sheet.

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