• Some releases are incidental in some cases and emergencies in others, depending on factors like the surroundings of the release and the equipment and personnel available to address it.

The properties of hazardous substances (such as toxicity, volatility, flammability, explosiveness, corrosiveness, etc.), as well as the circumstances of the release itself (such as quantity, confined space considerations, ventilation, etc.), have an impact on what employees can handle safely and what procedures should be followed.

Other factors may mitigate the hazards associated with a release and its remediation, such as:

• The training or experience of the employees in the immediate work area,
• The response and personal protective equipment (PPE) at hand, and
• The pre-established standard operating procedures for response.

Some engineering control measures can also be activated to assist in controlling and stopping the release.

These considerations combine to define the distinction between incidental releases and releases that require an emergency response. The distinction is site-specific, and its impact is a function of the emergency response plan (ERP).

For example, a spill of the solvent toluene in a facility that manufactures toluene may not require an emergency response because of the advanced knowledge of the nearby personnel and the equipment available to absorb and clean up the spill. However, the same spill inside a furniture refinishing shop whose personnel have had only basic hazard communication training on toluene may require an emergency response by more highly trained personnel. The furniture shop’s ERP would call for evacuation for all but the most minor spills, but at the chemical facility, evacuation and emergency response would be necessary only for much larger spills.

A fuel spill from an overturned aircraft would likely be emergency response due to the significant and uncontrolled hazards posed by the aircraft and jet fuel. Personnel would be conducting operations such as firefighting, passenger rescue, and working to stop the release of jet fuel. However, a fuel spill from a tanker truck that can be absorbed, neutralized, or otherwise controlled by employees in the immediate release area using absorbent pads may qualify as an incidental release if there are no significant health or safety hazards. (Note: If the release of jet fuel is covered by 40 CFR 300, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), an employer may be required by the Environmental Protection Agency (EPA) to follow the Hazardous Waste Operations and Emergency Response Standard.)