Protective Actions
Protective actions are the steps taken to preserve the health and safety of emergency responders and the public during an incident involving releases of hazardous materials.
Table 1 — [Initial Isolation and Protective Action Distances](/hazmat/protective-distance) (Green Section) predicts the size of the area that could be affected by a cloud of toxic gas. People in this area should be evacuated and/or sheltered-in-place.
The Three Actions
Isolate
Isolate hazard area and deny entry — keep everybody away from the area if they are not directly involved in emergency response operations. Unprotected emergency responders should not be allowed to enter the isolation zone. This is the first step for any protective actions that follow.
Evacuate
Move all people from a threatened area to a safer place. To perform an evacuation there must be enough time for people to be warned, get ready, and leave. If there is enough time, evacuation is the best protective action.
- Begin evacuating people nearby and those who are outdoors in direct view of the scene.
- When additional help arrives, expand the area to be evacuated downwind and crosswind to at least the extent recommended in the ERG.
- Even after people move to the recommended distances, they may not be completely safe. They should not be permitted to gather at those distances.
- Send evacuees to a definite place, by a specific route, far enough away so they will not have to relocate again if the wind shifts.
Shelter-in-place
People should seek shelter inside a building and remain inside until the danger passes. Maintain communications with sheltered-in-place people so that they are advised of changing conditions.
Used either when:
- evacuating the public would cause greater risk than staying where they are, or
- an evacuation cannot be safely performed.
Direct the people inside to:
- close all doors and windows
- shut off all ventilating, heating, and cooling systems
- stay far from windows to avoid shattered glass and projectile metal fragments in the event of a fire or explosion
- seal cracks around doors, windows, and vents with duct tape or wet cloths
- tune in to local media and remain inside until told it is safe to leave
- breathe through a wet cloth until an all-clear has been communicated
Vehicles can offer some protection for a short period if the windows are closed and ventilation is shut off, but vehicles are not nearly as effective as buildings for in-place protection.
Choosing Between Evacuation and Shelter-in-place
The right action depends on the situation. Consider:
The hazardous materials
- degree of health hazard
- chemical and physical properties
- amount involved
- containment / control of release
- rate of vapor movement
The population threatened
- location
- number of people
- time available to evacuate or shelter-in-place
- ability to control evacuation or shelter-in-place
- building types and availability
- special institutions or populations (nursing homes, hospitals, prisons)
The weather conditions
- effect on vapor and cloud movement
- potential for change
- effect on evacuation or shelter-in-place
Evacuate vs. Shelter-in-place — quick guide
| Consider evacuation when | Consider shelter-in-place when |
|---|---|
| Vapors are flammable. | Vapors are toxic and people are likely to be exposed by evacuating. |
| Buildings cannot be closed tightly. | Buildings can be quickly sealed by closing windows and ventilation. |
| Vapors are continuously generated, will hug the ground, or will take a long time to clear. | Vapors will quickly rise or dissipate. |
| For anyone outdoors. | For anyone already indoors. |
| There are few people to evacuate. | There are too many people to evacuate for current resources. |
| The threat seems stable but long-lasting. | Circumstances are changing too quickly to evacuate safely. |
> Every hazmat incident is different. Actions to protect the public must be carefully selected. Officials must continue to gather information and monitor the situation until the threat is removed.