Shelter in Place: Complete Guide to Staying Safe When You Can’t Leave

When authorities issue a shelter-in-place order, your instinct may be to grab your go-bag and leave. That instinct is wrong. Shelter-in-place orders exist because leaving puts you in greater danger than staying: whether from toxic chemicals in the air, radiological fallout, an active threat, or severe weather conditions where driving is more dangerous than your home. Understanding shelter-in-place supplies and procedures before an emergency is the difference between improvising under pressure and executing a practiced plan.

This guide covers every shelter-in-place scenario, the specific actions required for each, what supplies you need, and how to make decisions in real time.

Shelter in Place vs. Evacuate: How to Decide

The core decision framework is simple: follow official guidance if you receive it. Emergency managers issue shelter-in-place or evacuation orders based on real-time information you don’t have: the location and trajectory of a chemical plume, the path of a wildfire, or the projected flooding. When official guidance exists, follow it.

When you haven’t received guidance yet and must decide independently:

The key principle: a solid building protects you from many threats. Modern construction with closed doors, windows, and HVAC provides meaningful protection against airborne hazards: not perfect protection, but meaningful protection that far exceeds being caught outside or in a vehicle.

Shelter-in-Place Scenarios

Chemical / HAZMAT Events

Industrial accidents, train derailments, and chemical plant incidents can release toxic gases into the air. Your actions in the first few minutes are critical:

1. Go inside immediately: don’t stop to gather belongings from outside
2. Close all windows and doors
3. Turn off all HVAC systems (air conditioning, heating, fans, ventilation)
4. Move to your pre-selected interior room and seal gaps with plastic sheeting and tape
5. Tune to local emergency alerts (radio or phone)
6. Do not leave until authorities declare all-clear

Most chemical gases are heavier than air: upper floors provide some additional protection. However, the sealing of your chosen room matters more than floor selection.

Radiological Events

The most important thing to know about nuclear/radiological shelter-in-place: time, distance, and shielding all reduce exposure. The first 24 hours after a nuclear detonation produce the most dangerous fallout. After 24 hours, radiation levels from fallout decay to approximately 1/10th their initial intensity (the 7-10 rule).

• Move toward the center of the building and away from windows and exterior walls
• Basement is best: Below-grade rooms with concrete around you provide maximum shielding. A basement reduces radiation exposure by 90%+ compared to being outdoors.
• Middle floors of tall buildings are the second-best option if no basement exists
• Stay inside for at least 24 hours unless authorities direct otherwise
• Seal gaps with plastic and tape
• Turn off HVAC

Tornado and Severe Weather

Tornado shelter-in-place requires moving to the lowest floor, most interior room (no windows):

• Basement or lowest floor interior room (bathroom, closet, hallway)
• Away from all windows
• Cover yourself with a mattress or thick blankets if available
• Do not open windows (this does not equalize pressure: it wastes precious seconds)
• Abandon mobile/manufactured homes; find a nearby solid structure

Active Threat / Civil Unrest

Lock all entry points, move away from windows, silence your phone, and stay low. Shelter-in-place during active threat situations is part of Run-Hide-Fight guidance: when hiding is the appropriate response:

• Lock and barricade doors (desks, furniture against the door)
• Turn off lights
• Silence phone (not just vibrate: turn off notifications)
• Stay behind cover (solid walls, furniture), not just concealment
• Don’t open the door for anyone until all-clear from authorities

Selecting Your Safe Room

For chemical, radiological, and airborne hazard scenarios, select your shelter room in advance using these criteria:

• Interior location: As few exterior walls as possible, no windows preferred
• Above ground for chemical threats: Upper floors for heavier-than-air gases; basement for radiological threats
• Size: 10 square feet per person provides adequate air for several hours of sealed shelter
• Sealing feasibility: Fewer doors and windows = faster, more effective sealing
• Communication access: You need to receive alerts and updates

Good room choices: interior bathroom, large closet, laundry room, interior bedroom. Pre-measure the doorframe and window (if any) and pre-cut plastic sheeting to size. Label the rolls and store them in or near the room.

Sealing Your Home

For chemical and radiological shelter-in-place, sealing your chosen room significantly reduces contaminant penetration. This is not about achieving a perfect seal: it’s about reducing air exchange rate substantially.

What You Need

• 4-mil or thicker plastic sheeting (pre-cut to door and window sizes)
• Duct tape (2–4 rolls for a single room)
• Wet towels for door gap sealing (immediate, before plastic is applied)

Sealing Procedure

1. Turn off all HVAC before sealing
2. Bring everyone into the room with supplies
3. Place wet towels at the base of the door gap
4. Apply plastic sheeting over the door, taping all edges completely to the wall (not just the door frame)
5. If there are windows, cover them with plastic sheeting and tape all edges
6. Cover air vents with plastic sheeting and tape
7. Do not seal the room completely if you’re staying for more than 5–6 hours: you’ll need to manage CO2 buildup

Shelter-in-Place Supply List

Keep these items pre-staged in or near your designated shelter room:

Sealing Supplies

• Pre-cut 4-mil plastic sheeting (one piece per door/window)
• 4 rolls of heavy-duty duct tape
• Scissors or box cutter
• Wet towels (kept dry until needed: just regular towels)

Communication and Monitoring

• Battery-powered or hand-crank NOAA weather radio
• Fully charged smartphone with emergency alerts enabled
• Extra phone battery/power bank
• Paper list of emergency contacts

Water and Food

• 1 gallon per person per day (minimum 3-day supply accessible)
• Non-perishable food for 3 days per person
• Manual can opener
• Eating utensils

Sanitation

• Bucket with lid (emergency toilet)
• Heavy-duty garbage bags
• Toilet paper
• Hand sanitizer
• Baby wipes

First Aid and Medications

• Complete first aid kit
• 7-day supply of all prescription medications
• Pain relievers, antihistamines
• Any medical devices (glucose meter, inhaler, EpiPen)

Comfort and Function

• Flashlights with extra batteries
• Blankets or sleeping bags
• Books, cards, offline entertainment for children
• Activities for children (reduces anxiety significantly)

Air Quality and Filtration

Your home HVAC system’s filter does not protect against most chemical agents. Standard HVAC filters are designed for particulate matter: they won’t stop chlorine, ammonia, or other gas-phase chemicals. The most effective protection is sealed containment combined with minimizing air exchange.

For households in high-risk areas (near industrial facilities, rail corridors, military installations), consider upgrading your permanent HVAC filter to a MERV 13+ filter, which provides meaningful protection against certain particulate radiological threats and some heavier aerosols. This won’t replace sealing during an active event but provides passive protection during low-level exposures.

N95 respirators can bridge the gap if you need to move through a potentially contaminated area briefly. They do not replace sealed shelter but provide meaningful protection for short-duration exposures to particulate hazards. Keep one per person in your shelter kit. Note: standard N95s do not protect against gas-phase chemical threats: only full-face respirators with appropriate cartridges provide protection there.

Water and Food During Shelter-in-Place

During most shelter-in-place events, your home water supply remains safe: the threat is airborne, not to your plumbing. However, in radiological and some chemical events, well water should be treated as potentially contaminated until tested. Municipal water from ground-fed systems generally remains safe during airborne events.

Practical guidance:

• Fill your bathtub immediately when a shelter-in-place order is issued: before contamination becomes possible and before water pressure may drop
• A WaterBOB or AquaPod bathtub liner keeps bathtub water cleaner and accessible for up to 4 weeks
• Keep tap water running for drinking and cooking unless authorities specifically say not to
• In radiological events: cover food and water, avoid produce that was outdoors during the fallout period

For food, prioritize shelf-stable items that don’t require extensive cooking: heat generates smells that can affect air quality in a sealed room. Crackers, peanut butter, canned goods, granola bars, and dried fruit are practical shelter-in-place food choices.

Power Considerations

Shelter-in-place scenarios often coincide with power outages. Prepare for power loss as a companion condition to any shelter-in-place scenario:

• Do not use generators inside: Carbon monoxide is silent and fatal. Generators must run outside, at least 20 feet from any window or door. During chemical shelter-in-place, you cannot run a generator safely because opening windows/doors defeats the sealed environment.
• Battery power banks: Large capacity power banks (20,000+ mAh) can keep phones charged for multiple days without a generator
• Battery-powered lighting: LED lanterns and headlamps rated for 100+ hours are sufficient for most shelter-in-place durations
• Heat in winter: A sealed interior room retains body heat reasonably well for short durations. Add sleeping bags and blankets. Do not use propane heaters in a sealed room: carbon monoxide risk.
• Cooling in summer: Battery-powered fans provide comfort but no cooling. Hydration and wet cloth on pulse points are your primary tools.

Monitoring and Communication

Staying informed during shelter-in-place is critical: you need to know when the threat passes and it’s safe to leave.

Primary Alert Sources

• Wireless Emergency Alerts (WEA): Automatically pushed to your phone by cell towers for imminent threats. Ensure WEA is enabled in your phone settings (Settings → Notifications → Emergency Alerts).
• NOAA Weather Radio All Hazards: Broadcasts continuous weather and hazard information 24/7. A battery-powered weather radio is your primary information source when cell service is degraded.
• Local AM radio: Emergency broadcast stations operate on generator backup during power outages. Tune to your local emergency broadcast station (listed in your community’s emergency plan).

Communicating Your Status

• Text your out-of-area contact as soon as shelter-in-place begins
• Text is more reliable than voice calls during emergencies: networks handle text traffic far better than voice
• Update your out-of-area contact every 2–3 hours so rescue workers have current information if needed

When and How to Leave Safely

Do not leave your shelter until you receive an official all-clear from authorities. “I’m getting bored” and “I’m guessing it’s probably fine now” are not reasons to unseal your shelter room.

When the all-clear is issued:

1. Remove plastic sealing from doors and windows
2. Open windows and doors to ventilate: allow 15–30 minutes of ventilation before using home normally
3. Check on neighbors, especially elderly or disabled individuals who may need assistance
4. In radiological events: shower with soap and water (do not use conditioner: it binds particles to hair), bag and store the clothing you wore
5. In chemical events: if you experienced any exposure symptoms (burning eyes, throat irritation, difficulty breathing), seek medical attention even after the all-clear

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