Everything you need to gather before going inside for 24–48 hours of nuclear shelter-in-place, including water, food, medications, and communications.
Effective nuclear shelter-in-place has two components: the building itself (shielding mass, sealable gaps) and the supplies that allow you to remain inside without opening doors or windows for the critical first 24–48 hours. The fallout dose rate declines dramatically over this period — a person who remains inside for 24 hours after a detonation receives a fraction of the dose of a person who goes outside even briefly during the peak fallout period.
This guide covers what to have ready and where to source each category of supply, with the understanding that the best time to gather supplies is now — not after a detonation, when you may have only minutes before fallout arrives.
The fundamental challenge of nuclear shelter-in-place is that you cannot open doors or windows to replenish supplies once fallout is arriving. This means:
The gap between the detonation and fallout arrival is typically 15 minutes to an hour depending on your distance from the detonation point and wind conditions. If you are at home when the detonation occurs, you may have a brief window to gather critical items — but do not use this window unless you are confident you can complete gathering and sealing before fallout arrives.
Water is the single most critical supply. Tap water from sealed municipal pipes is safe to drink even after a nuclear event — the contamination concern is with surface water and with water that is exposed to fallout particles. Pipes are sealed systems; the water inside them at the time of the detonation is uncontaminated.
WARNING: Act quickly when the detonation occurs. If the municipal water supply loses pressure (common after a major detonation due to infrastructure damage), you cannot fill containers from the tap. Fill all available containers immediately.
How much water:
What to fill:
Pre-stocked water: Maintain at least 12 litres of bottled or stored water per person in your home at all times. This eliminates the scramble to fill containers immediately after a detonation.
During the shelter period, the food priority is simple: caloric adequacy and nutrition from sealed containers. You are not cooking elaborate meals — you are maintaining energy and morale.
Food requirements for shelter:
What to avoid during shelter:
Estimated food quantities for 48 hours (per adult):
| Category | Amount | Notes |
|---|---|---|
| Canned goods | 4–6 cans | ~400–600 kcal per can |
| Crackers/dry food | 500g | Snacking and meal supplement |
| Protein bars or similar | 4–6 bars | ~200–300 kcal each |
| Comfort/treat items | As available | Morale is a real survival factor |
This is the category where most shelter plans fail. People with chronic conditions who do not have a supply of their medications on hand cannot safely shelter for 48 hours without risking medical complications.
Chronic condition medications that cannot be interrupted:
Potassium Iodide (KI): If you have access to KI tablets (available over-the-counter in many countries, distributed by some civil defence programmes), include them in your shelter kit. KI protects the thyroid from radioactive iodine-131 in fallout, but must be taken before or within a short time after exposure. Dosage varies by age — see the KI dosing guide for children and adults. Take only on instruction from official emergency authorities — unnecessary administration has risks.
Medications to include in shelter kit:
| Category | What to Stock |
|---|---|
| Pain/fever | Paracetamol/acetaminophen, ibuprofen |
| Anti-nausea | Promethazine, ondansetron if available (ARS causes nausea) |
| Allergy/antihistamine | Diphenhydramine or similar |
| Diarrhoea | Oral rehydration salts (ORS), loperamide |
| First aid | Bandages, antiseptic, tweezers, scissors |
| Thyroid protection | KI if available and appropriate |
| Personal prescriptions | Full supply for at least 72 hours |
A battery-powered or hand-crank radio is the most important information device in nuclear shelter-in-place. Mobile phone networks will be overloaded or non-functional. The internet may be unavailable. Emergency broadcasts on AM/FM and NOAA Weather Radio are the primary channel for:
A radio that does not require electricity from the grid — battery or hand-crank — is essential. At least one spare set of batteries should be kept with the radio.
WARNING: Do not rely on smartphone apps, social media, or internet streaming for emergency information during a nuclear event. Networks will be disrupted; battery life is limited; and social media during acute nuclear events is heavily populated with misinformation that can lead to fatal decisions.
If the detonation has damaged infrastructure, power may be out. Keep:
Candles work but produce combustion products and pose fire risk in a sealed shelter. Prefer battery lighting.
A 48-hour shelter-in-place without opening windows presents sanitation challenges.
Toilet use: The flush toilet remains functional as long as water pressure is maintained in the supply pipe. Use normally. If water pressure fails, a bucket flush (pour water directly into the bowl) works with approximately 6 litres of stored water per flush.
No-flush backup: Maintain a camping toilet, chemical toilet, or lined bucket with lid as backup. Heavy-duty rubbish bags and kitty litter or sawdust can create a functional emergency toilet.
Hygiene: Antibacterial wipes allow hand and body cleaning without using much water. This is particularly important after decontamination (removing outer clothing and washing skin).
Waste management: During sealed shelter, keep waste bags closed and in a designated corner of the shelter. Do not open exterior doors to take out rubbish — this can wait.
Include pets in your shelter plan. Animals that were outdoors during fallout deposition should be decontaminated before entering the shelter space.
Pet decontamination:
Pet supplies for shelter:
The ideal scenario is that all shelter supplies are already assembled and your shelter room is identifiable in advance. The "just-in-time" alternative — gathering supplies in the minutes after a detonation — is feasible but risky.
If you must gather quickly (post-detonation):
The entire gathering process should take less than 5 minutes. Pre-identify where everything is now so you are not searching during an emergency.
| Category | Minimum for 48 hrs (4 people) | Pre-stocked? |
|---|---|---|
| Water | 32+ litres (8 litres/person) | Maintain 12+ litres bottled at all times |
| Food | Sealed cans + dry food for 2 days | Keep 3-day supply in pantry |
| Medications | Full supply + extra | Review quarterly |
| KI tablets | 1 per family member (if available) | Available OTC; check local availability |
| Battery radio | 1 with spare batteries | Check batteries annually |
| Flashlights | 2+ with spare batteries | Check batteries annually |
| Power bank | 1 fully charged | Charge monthly |
| First aid kit | Complete kit | Review annually |
| Sanitation supplies | Wipes, backup toilet option | Maintain |
| Pet supplies | 48–72 hrs food and water | Maintain |
The time to assemble shelter supplies is now, not after the detonation. A preparedness mindset that treats this as routine insurance — not a paranoid extreme — produces the supplies and knowledge needed to survive a scenario that, while rare, is not impossible.
Take Supplies for Nuclear Shelter-in-Place with you — no internet needed when it matters most.
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