Chemical Hazard Control (HOC) Strategies
Hazardous substances can be used safely in workplaces if adequate control strategies are used to prevent exposure to those chemicals.
A control strategy includes any device, procedure, piece of equipment, system, etc., that is used to keep hazardous chemicals from contacting workers at harmful levels. Traditionally, a prioritized "Hierarchy of Controls" (HOC) has been used to implement feasible and effective exposure controls to protect workers. We encourage the use of the HOC model as described within the ANSI/ASSP Z10, Occupational Health and Safety Management Systems, to control hazards. The six strategies are discussed below.
The first three HOC strategies focus on addressing the hazard directly to eliminate or reduce exposure and risk.
- Elimination: The best solution is to totally eliminate hazardous substances in the workplace.
- Substitution: Substitution is the next-best solution. Replace a toxic substance with a less-toxic substance. If you can't get rid of the toxic substances, you may be able to replace them with substances that are at least less toxic. For more information on safer alternative chemicals to use in the workplace, see the ChemHAT Chemical Hazard and Alternatives Toolbox.
- Engineering Controls: Redesign or modify processes that use toxic chemicals to eliminate or reduce exposure to the chemical hazard itself.
The next three HOC strategies aim to modify behaviors in order to reduce exposure to the hazard.
- Warnings. Use container labels and signs to warn employees about the dangers of the chemicals they are using.
- Work Practice Controls: Change work procedures to reduce the duration, frequency, and severity of exposure to the chemical hazard. The chemical hazard, itself, is not eliminated or reduced using this strategy. The primary focus is to incorporate safer work practices through written safety policies, rules, supervision and training. And that's a problem because you may have to regularly supervise employees as they perform a task. These controls work only so long as employees "behave" properly.
- Personal Protective Equipment (PPE): The use of PPE is probably the most common strategy, and mandatory when working with hazardous chemicals. PPE forms a barrier between worker and hazard. Once again, the chemical hazard is neither eliminated nor reduced, and a high reliance is placed on appropriate use of PPE for this strategy to be successful.
Remember, the first question to ask is, "How can I eliminate, reduce, or engineer out the hazard?" Hopefully you'll be able to eliminate the hazard or reduce it to the point where safe behaviors or PPE won't be necessary.
Interim Measures
Using a lower priority hazard control method over another higher priority control strategy may be appropriate for providing interim (temporary) protection until the hazard is abated permanently. If you can't eliminate the hazard entirely, the interim control measures will likely be a combination of control methods used together. OSHA believes that feasible interim measures are always available if higher-level control methods are not possible.
Knowledge Check Choose the best answer for the question.
2-6. What HOC strategy would be the first to consider when trying to reduce exposure to hazardous chemicals?
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