Chapter 28. Hazardous-Material Incidents and Shelter-in-Place Instructions
A hazardous-material incident may involve chemicals, fuel, smoke, toxic gases, industrial substances, agricultural products, or other dangerous materials released during a transportation accident, facility emergency, fire, equipment failure, or intentional act. Depending on the substance, wind direction, location, and expected duration, authorities may instruct residents to evacuate—or to remain indoors and shelter in place.
Residents of Pleasanton, Dublin, Livermore, San Ramon, Danville, Sunol, and surrounding Tri-Valley and Bay Area communities should understand both actions. Leaving is not automatically the safest response. If hazardous material is moving through outdoor air, evacuating could place residents directly in the affected area, increase exposure, congest roads needed by emergency responders, or send drivers toward the release.
Follow the Protective Action Ordered
Fire departments, law-enforcement agencies, hazardous-material teams, public-health officials, and emergency-management authorities evaluate the incident before recommending protective action. They may consider:
- The identity and concentration of the material
- Whether it is a gas, vapor, liquid, powder, smoke, or another substance
- Wind direction and speed
- The location and size of the release
- The expected movement of the hazardous plume
- Available evacuation routes
- The time required to move residents safely
- Whether nearby buildings provide temporary protection
A shelter-in-place instruction means residents should enter or remain inside an appropriate building and reduce their exposure to outdoor air. It does not necessarily mean that every room is completely sealed or that the building will remain safe indefinitely. It is a temporary protective measure used while authorities control the incident, monitor conditions, or arrange further action.
An evacuation order means the area is unsafe for residents to remain. Follow the specific instruction issued for your location rather than assuming that a response appropriate for another neighborhood applies to yours.
Enter a Suitable Building
If authorities issue shelter-in-place instructions, go indoors immediately. Bring children and pets inside when this can be done without entering a contaminated or restricted area. Close and lock exterior doors and windows. Locking them may help create a tighter seal.
Choose an interior room with as few windows, exterior doors, and ventilation openings as possible. Move emergency supplies into the room, including:
- Drinking water
- Essential medication
- Phones and charging equipment
- A battery-powered or hand-crank radio
- Flashlights
- Pet supplies
- Basic sanitation items
- Materials for temporarily covering openings if directed
If household members are at work, school, childcare, or another facility, do not automatically drive through the affected area to collect them. Those locations may have their own emergency plans and may already be sheltering safely. Follow official reunification instructions.
Reduce the Entry of Outside Air
When officials instruct you to do so, turn off systems that draw outdoor air into the building. These may include:
- Central heating and air-conditioning systems
- Whole-house fans
- Window or portable air conditioners
- Bathroom and kitchen exhaust fans
- Clothes dryers
- Fireplace dampers
- Other mechanical ventilation systems
Set systems to recirculate indoor air only if authorities recommend that setting and the system can operate without bringing in outside air. Building ventilation systems differ, so households should learn in advance how their equipment works.
Officials may also direct residents to cover vents and gaps around doors or windows temporarily with plastic sheeting and tape. Prepare these materials before an incident and store them with emergency supplies. Do not spend excessive time attempting to make a room perfectly airtight. Follow the instructions given for the specific emergency.
Ready.gov provides additional information about hazardous-material incidents and sheltering indoors.
Monitor Current Official Messages
Hazardous-material conditions can change quickly. A shelter-in-place instruction may later be expanded, reduced, replaced by an evacuation order, or ended with an official all-clear.
Keep monitoring:
- Wireless Emergency Alerts
- City and county emergency notifications
- Local fire and law-enforcement agencies
- A battery-powered radio
- Official government websites and social-media accounts
- Instructions issued through schools, workplaces, or building managers
Do not rely solely on neighborhood messages, unofficial maps, photographs, visible smoke, or odor. Some dangerous substances cannot be seen or smelled, while an odor may remain after the most serious danger has passed.
Avoid unnecessary telephone calls to 911. Use 911 for life-threatening emergencies, active exposure, fire, serious symptoms, or immediate danger.
Avoid the Affected Area
Do not go outside to investigate, take photographs, watch emergency operations, or determine where the odor originated. Keep away from barricades, emergency vehicles, spill sites, drainage systems, and visibly contaminated areas.
Never touch, smell, taste, move, or clean an unidentified substance. Do not enter a contaminated area to retrieve belongings or pets. Driving may carry you into the hazardous plume, and vehicles are generally less protective than substantial buildings.
If you are already driving when an alert arrives, close the windows and vents and set the ventilation system to recirculate. Leave the affected area only along the route authorities specify, or enter the nearest suitable building when instructed. Do not stop beneath bridges, inside tunnels, or where your vehicle obstructs emergency access.
Respond to Possible Exposure
If a chemical contacts your skin or clothing, move away from the source and follow official decontamination instructions. Removing contaminated outer clothing may eliminate much of the chemical, but different substances require different responses. Do not improvise with cleaners, bleach, neutralizing chemicals, or household remedies.
Call 911 for severe breathing difficulty, chest pain, unconsciousness, seizures, confusion, significant burns, or another medical emergency. Poison Control can be reached in the United States at 1-800-222-1222 for exposure guidance. The CDC explains what to do during a chemical emergency.
A suspected natural-gas leak inside a building generally requires leaving immediately, not sealing yourself inside. Avoid switches, flames, phones, vehicles, or anything that could create a spark; call 911 and the gas utility from a safe location.
Wait for the Official All-Clear
Remain sheltered until authorities announce that it is safe to leave or provide new instructions. Do not open windows or restart ventilation merely because the odor disappears.
After the all-clear, officials may direct residents to ventilate buildings, avoid certain outdoor areas, dispose of contaminated items, obtain medical evaluation, or continue monitoring updates. Follow those directions carefully. CDC guidance emphasizes waiting for instructions from police, fire, or other local officials before leaving a shelter-in-place location during a chemical emergency.
Helpful Hint
Do not evacuate automatically during every emergency. Leaving may increase exposure if authorities have issued shelter-in-place instructions. Enter a suitable building, reduce the entry of outside air as directed, and monitor official messages.
Important Safety Reminder
Shelter-in-place and evacuation instructions are specific to the incident and location. Follow the current order issued for your area, remain away from the release, and do not leave shelter until authorities provide an all-clear or direct you to evacuate.
Important Preparedness and Safety Notice
This chapter provides general preparedness education, not real-time emergency instructions. Conditions, evacuation zones, routes, shelters, road closures, and public-safety directions can change rapidly. During an emergency, consult current information from authorized public agencies and follow all instructions issued by emergency officials. Call 911 for an immediate threat to life, active fire, serious injury, crime in progress, or another urgent emergency.
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