When should a first responder refer to the ERG's Table of Initial Isolation and Protective Action Distances?

• A. Whenever the material entry in the ID Number and Name Indexes is highlighted and fire IS NOT involved
• B. Whenever there is a fire involved
• C. Only for large spills
• D. Only when there is no hazard present

Answer: (C)

The main idea being tested is when to use the ERG’s Table of Initial Isolation and Protective Action Distances. This table is a quick, conservative guide for deciding how far to isolate the area and what protective actions to recommend when a release could create a significant hazard for people beyond the immediate scene. It’s intended for large releases where the potential for widespread exposure is real, so establishing a safe perimeter early helps protect responders and the public while more information is gathered.

For small spills, the risk is typically limited and can often be managed with standard scene safety and containment steps without needing the table’s distance guidance. So the table is most appropriate to consult when the spill potential is large enough to require substantial protective actions, which is why the correct approach is to refer to it for large spills.