Safetip #7: Control Chemical Exposure at the Source

December 09, 2015

In this week’s Safetip, we take a look at workplace chemical exposure, and how exposure should be controlled at the source, whenever possible.

Follow the Hierarchy of Controls

Exposure to hazardous workplace chemicals can create risks of skin irritation, respiratory issues, eye irritation, etc. To protect workers from potential health effects, a number of controls can be put in place designed to reduce risks from chemical exposure hazards. There are different types of controls. Each has its own level of effectiveness, implementation costs, and level of process changes.

The following representation from NIOSH shows the hierarchy of controls:

Hierarchy Controls

While “elimination” is the most effective control, eliminating a process that makes use of hazardous chemicals may be very costly and difficult to implement for existing processes. If the process cannot be eliminated, the next best thing is to control chemical exposure at the source, in order to protect workers in an effective way. We will focus on three types of controls in this post: Substitution, Engineering Controls, and Administrative Controls.

Substitute for a Safer Chemical

If you can’t completely eliminate the process, the next most effective control is to substitute a hazardous chemical for a safer one. It is important to make sure that the substitute chemical is not harmful, and to control and monitor exposures to make sure that the replacement chemical is below occupational exposure limits (OELs).

You can also consider using the same chemical in a different form. For example, a material in powder form that may be an inhalation hazard can be substituted in favor of the same material that is also available in pellet form.

Finally, it’s important to emphasize that substituting chemicals requires research and experimentation. It is not an exercise that should be taken lightly. The EPA’s Safer Choice program provides a list of safer alternatives for many workplace chemicals. In addition, OSHA provides a toolkit for employers that want to make the transition to safer chemicals.

Implement Engineering Controls

If you can’t substitute the hazardous chemical for a safer one, the next most effective way to control chemical exposure is to implement engineering controls, which aim to prevent hazardous chemicals from coming in contact with the worker. Engineering controls are built into the design of a plant, equipment or process to minimize the hazard. They are a very reliable way to control exposure as long as the controls are designed, used and maintained properly.

Engineering controls can involve enclosing or isolating the process. Isolating the source of chemical exposure can be done through separate rooms or buildings, and closed doors. If using a separate room is not possible, certain operations can be completely enclosed in other ways to protect workers, such as splash guards, hoods over machine operations using cutting fluids, fume hoods, etc. Other types of engineering controls besides enclosure and isolation include: 1) Process control: changing the way an activity or process is done to reduce the risk, and 2) Ventilation: adding or removing air, such as removing or diluting an air contaminant.

Implement Administrative Controls

Administrative controls are the least effective controls, after Personal Protective Equipment (PPE). They are less costly to implement, but can be costly to sustain in the long-term. Administrative controls aim to reduce exposure to chemical hazards by improving the efficiency of processes and procedures. For example, shorter work times in contaminated areas can be scheduled. Other methods include:

  • Scheduling operations for times when few workers are present (evenings, weekends).
  • Rotating job assignments that limit the amount of time an individual worker is exposed to a chemical.
  • Work-rest schedule that limits the length of time a worker is exposed to a chemical.
  • Restricting access only to a limited number of essential employees.

It’s very important to note that administrative controls do not remove or reduce the actual hazard. As a result, many EHS professionals do not favor administrative controls because they can be difficult to implement and maintain, and they are not a reliable way to reduce exposure.

Additional Resources

Here are links to additional resources on controlling chemical exposure, some of which were used for this post:

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