Safetip #27: 7-Step Process for Chemical Substitution

May 04, 2016
By Jean-Grégoire Manoukian

This week’s Safetip is about the substitution of hazardous chemicals. In order to control risks, sometimes it may be necessary to eliminate certain hazardous chemicals, or processes that make use of hazardous chemicals. But when “elimination” is not feasible, “substitution” should be considered, which is the second most effective control in the hierarchy of controls.

To successfully substitute a hazardous chemical, you need to effectively investigate alternatives. The Health and Safety Executive (HSE) in the U.K. has come up with a seven-step process when considering substitution. An adapted version of the process is outlined on the website of the Canadian Centre for Occupational Health & Safety:

1) Identify hazards and assess risks

Decide whether the current substance is a hazard (potential to harm human health or the environment). Is there a significant risk involved in storing, using or disposing of the substance?

2) Identify alternatives

Investigate a number of options. Compare all of the hazard assessment information. Compare the different states of the chemical (e.g. will a granular form create less dust than a powder form?). If you are a supplier, you may need to select options according to your customers’ needs and those of your own workers.

3) Think about what could happen if you use the alternatives

It is important to gather all the available information before this step so you can make a realistic assessment. You must also consider the way employees use the alternative chemical and how likely they are to be exposed to it. Choosing an alternative chemical may require changes in:

  • The way the work is done.
  • The kind of equipment or parts needed to be compatible with the substitute chemical.
  • The ventilation system that may be required.
  • The disposal methods.
  • Regulatory requirements that may apply.

4) Compare alternatives

Compare the alternatives with each other, and with the substance currently being used. For example, think about the following:

  • Is the substitute chemical going to explode or poison people?
  • Will it only affect people who work with it, or could it affect other people in the area?

Remember to consider how and where the alternative will be used.

5) Decide whether to substitute

This step is the most difficult, according to the HSE. Consult with the workers who will be handling the material directly for their input. It may be a good idea to introduce the substitute chemical as part of a trial, or in a small quantity to begin with.

6) Introduce the substitute

Plan the change in material or process carefully. Train and educate all the workers involved.

7) Assess the change

Check to see if the substitution has produced the intended results by:

  • Monitoring the health of workers.
  • Monitoring the level of contaminants in the air.
  • Determining if regulatory requirements associated to the new chemical, if applicable, have been fulfilled.

Finally, if eliminating or substituting the chemical is not feasible, keep in mind that you may be able to reduce the risks from chemical exposure hazards through other controls, such as engineering controls, administrative controls, or personal protective equipment (PPE). But even for these types of controls, a thorough assessment of feasibility, effectiveness and costs should be made.