Workplace Solutions Hazard communication

‘Incidental’ vs. ‘emergency response’ releases

What’s the difference between an incidental release and a hazardous substance release that requires an emergency response?

Responding is Tricia S. Hodkiewicz, editor, J. J. Keller & Associates Inc., Neenah, WI.

According to 29 CFR 1910.120, OSHA’s Hazardous Waste Operations and Emergency Response (HAZWOPER) Standard, incidental hazardous substance releases can be absorbed, neutralized or otherwise controlled at the time of release by employees in the immediate release area or by maintenance personnel. Emergency response releases are the opposite. They result, or are likely to result, in an uncontrolled release, and response efforts are made by employees from outside the immediate release area or by other designated responders.

Because releases without emergency consequences are not covered by the emergency response provisions of the HAZWOPER standard, it is important to understand the difference between an “incidental” and an “emergency response” release. OSHA has stated that the distinction between the two has been a point of considerable inquiry. Perhaps this is because several factors make up the determination. Incidental releases often are limited in quantity, but the quantity of the release does not, by itself, determine if an incidental release has occurred. A small amount of a highly toxic substance may still pose an emergency, so you should look at the properties of the hazardous substance involved. Consider how toxic, volatile, flammable, explosive or corrosive the substance is. If the substance in the volume released does not pose a significant safety or health hazard to employees in the immediate vicinity, it may be an incidental release, but a few other factors should be examined before reaching that conclusion.

According to OSHA, the circumstances of the release impact what employees can and cannot do safely. Certainly if the release is sizable, it may be beyond what they can handle safely, but the agency also mentions confined-space and ventilation considerations. What employees actually face dictates whether incidental-release procedures can be followed or whether the release is more than incidental.

In addition, hazard-mitigating factors such as employee knowledge, personal protective equipment and standard operating procedures also must be taken into account. Let’s say your employees in the immediate vicinity of the release have advanced knowledge about the substance, routinely follow standard procedures using proper personal protective equipment, and have equipment readily available to absorb and clean it up. In this situation, the release is less likely to become an uncontrollable emergency in a short amount of time. The release would remain, in most cases, incidental.

If you consider the properties of the substance, the circumstances of the release and the mitigating factors, you should be able to make the distinction between an incidental release and one that is an emergency. To aid in this process, OSHA has provided a list of situations that it believes would “normally” require an emergency response effort, including:

  • High concentrations of toxic substances
  • A life- or injury-threatening situation
  • Immediately dangerous to life or health environments
  • Oxygen-deficient atmospheres
  • Fire or explosion hazards
  • A situation that requires an evacuation of the area
  • A danger in the area that requires immediate attention

Finally, note that some hazardous substance releases may pose such a significant safety or health threat that they require an emergency response regardless of the circumstances and mitigating factors.

Editor's note: This article represents the independent views of the author and should not be construed as a National Safety Council endorsement.

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