Control Exposure to Hazardous Chemicals at the Source - Safetip #156

Safety Tip and Best Practice
January 23, 2019

This week’s Safetip is about controlling workplace exposure to hazardous chemicals at the source whenever possible.

Use the Hierarchy of Controls

Exposure to hazardous chemicals at the workplace can cause risks of illnesses or health issues, including eye irritation, skin irritation, respiratory issues, cancer, and other diseases. Personal protective equipment is not the best solution. In fact, it’s the least effective method. NIOSH’s hierarchy of controls shows the most effective control methods for hazards, including workplace exposure to chemicals:

Hierarchy of Controls

The control methods at the top of the graphic are more effective and protective than those at the bottom. However, they can also be potentially costlier and less feasible. Organizations must aim to implement the most effective control methods that are possible under the circumstances.

Eliminate, Substitute, or Isolate


In the context of chemical exposure, the best way to protect workers is to address exposure at the source. Using the hierarchy of controls, the most effective method is “elimination” where the process or task is either completely removed, or changed to no longer make use of chemicals. However, in the context of workplace exposure to chemicals, this control method may be difficult to implement sometimes.


The second most effective control method, “substitution”, is much more feasible that elimination. In this case, the chemical is substituted for a less hazardous one, or the same chemical is used in a different form to reduce exposure. Here are some examples:

  • Replacing a chemical in powder form with the same chemical in pellet form.
  • Mixing a material with water to prevent dust from being created.
  • Replacing an organic solvent with a water-detergent solution.
  • Using steam cleaning instead of solvent degreasing.

Engineering Controls

If elimination and substitution are not feasible, then consider engineering controls to isolate workers from the hazardous chemicals, enclose the process, or reduce exposure. Engineering controls consist of changes to a plant, work area, equipment, job activity or process to minimize hazards. Engineering controls don’t remove the hazard, but they reduce or eliminate exposure by preventing chemicals from coming in contact with workers. Here are some examples:

  • Installing a local exhaust ventilation system to remove air contaminants.
  • Spraying water over a dusty surface to keep dust levels down (“Wet method”).
  • Using electric motors instead of diesel ones to eliminate diesel exhausts.
  • Using automation (e.g. mechanical arms) to handle or move hazardous materials.

In conclusion, follow the hierarchy of controls, and select the most effective and feasible methods for controlling exposure to hazardous chemicals at the source.

Each week we publish a Safetip where we share a safety tip or best practice that contributes to safety excellence. Visit Enablon Insights again next Wednesday for a new Safetip!

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Jean-Grégoire Manoukian

Content Thought Leader