UNITED STATES — If a chemical spill, industrial release or hazardous-materials accident happens near your home, do not drive or walk towards it. Follow your local fire department and emergency management instructions immediately. They may direct you to SHELTER IN PLACE, sealing your home against outside air, or to EVACUATE using a specified route. These choices are different: do not substitute one for the other based on a social media post. If someone is in immediate danger, call 911. For possible poisoning or chemical exposure, Poison Control is 1-800-222-1222.
The Centers for Disease Control and Prevention (CDC) summarises chemical emergency response as: get away from a release, get contaminants off the body if exposed, and get help. The correct route, protective room and decontamination method depend on the chemical and current conditions.
12 things to do now — chemical emergency checklist
- Stay away from the release. Do not approach a derailed train, leaking industrial tank, truck or unknown cloud to identify what is spilling.
- Check official instructions for your exact location. Firefighters, police and local emergency managers determine whether you should shelter or evacuate.
- If told to shelter, get inside and bring pets with you. Close and lock doors and windows promptly.
- If sheltering, turn off systems bringing outside air indoors. Follow CDC directions for fans, air conditioners, furnaces, vents and a suitable interior safe room.
- Use your designated safe room if directed. CDC advises a room on the highest floor practicable, with few windows, that can be sealed from outside air, unless authorities specify another location.
- Seal openings using prepared supplies when instructed. Plastic sheeting, tape and towels may help reduce infiltration; do not delay getting indoors to make elaborate covers.
- If ordered to evacuate, leave on the indicated route. Do not drive through the release area or try a shortcut across an emergency closure.
- If outside near the plume, move away from it safely. Stay upwind when possible and follow official guidance rather than walking closer for a photograph.
- If chemical material is on your body, get away and get clean. Remove contaminated outer clothing and wash or shower following CDC and emergency-service instructions.
- Do not attempt to neutralise unknown chemicals. Do not mix products or scrub contaminated skin with household cleaners; particular chemicals can require special handling.
- Call for medical or poison guidance. Dial 911 for life-threatening symptoms, or 1-800-222-1222 for US Poison Control where appropriate.
- Stay informed and do not return until the all-clear. Even after a cloud disappears, air, surfaces or water may remain unsafe.
If an alert is active at your address, stop reading after this checklist and follow the issuing authority. A web article cannot identify the chemical, plume direction, safe evacuation route or duration of a release in real time.
Why the shelter-or-evacuate decision matters so much
The instinct to get into a car and leave is not always safe. For some industrial releases, driving out may mean entering a toxic cloud. Other incidents require leaving because the building is inside an explosion, fire or contamination zone. CDC’s June 2026 guidance stresses listening to police, fire services or local officials to determine which option is safer.
Shelter in place means entering a suitable building, reducing outside-air entry and remaining inside until further notice. It may last a few hours or longer depending on conditions. Evacuation means leaving the threatened area through an official route to a safer location or designated shelter. The instructions may change as responders learn more about the release.
The type of chemical, wind and weather, ground-level conditions and whether fire or explosion is present all affect the decision. Do not determine safety from smell alone. Some hazardous substances have little noticeable odour, while a strong odour does not by itself establish the concentration or exact toxicity.
A useful general rule is to follow the order for your exact address. A nearby neighbourhood may have been told to leave while yours was told to stay indoors. Do not copy a different town’s instructions simply because both are close to the same railway line or industrial facility.
How to shelter in place at home
CDC recommends choosing a room that can be sealed from outside air, preferably at the highest feasible point with few windows, and with access to water. If possible, prepare the room and required supplies before an emergency. During an actual alert, do not spend valuable time searching for the ideal room when a suitable room is close by.
Get everyone and pets indoors. Shut and lock windows and external doors. Turn off air-conditioning, mechanical ventilation, exhaust fans and heating systems that draw outside air into the building, as appropriate to their design and the official instructions. Close fireplace dampers and vents where applicable. Do not disable medically essential equipment or create another hazard without seeking emergency advice.
In the chosen room, use prepared plastic sheeting and duct tape to seal windows, vents and gaps if the authority directs that level of protection. CDC identifies plastic sheeting, duct tape, towels and scissors as part of a chemical-emergency shelter kit. People who cannot carry out physical sealing should tell responders or carers about their needs.
Keep your phone, portable radio, water, medications and power supplies in the room. Monitor official updates rather than repeatedly opening the door or going outside to judge the smell. If someone develops severe symptoms, call 911 and explain that you are sheltering because of a chemical release.
What if your home has a basement?
The CDC chemical shelter guidance generally prefers a high floor for the safe room when possible. Some toxic gases can collect near the ground, but do not treat this as a universal chemical rule. A specific local order may identify a different location because of the actual substance, fire or building characteristics.
Follow the incident commander’s guidance. Avoid moving between floors repeatedly or entering a hazardous area to test air. If you are uncertain about which room to choose, seek the safest available indoor location while continuing to monitor the local alert.
What if you live in a high-rise apartment?
Building management may provide floor-specific instructions and secure central air intakes. Do not assume a condominium corridor, lift lobby or car park has cleaner air than the flat. Stay in the directed area, shut accessible openings and report residents who need assistance.
For a person using an oxygen concentrator, dialysis equipment or an electrically powered medical device, identify emergency backup needs. Do not turn essential equipment off solely because a general checklist says to stop ventilation. Ask emergency dispatch or the relevant medical professional about safe operation.
How to evacuate during a hazardous chemical release
If local authorities order evacuation, leave promptly on the designated route. CDC recommends preparing several routes in advance, a small go-kit and a way for family members to communicate when separated. Actual incident routes override your preferred road or map application.
Take medicines, identification, a phone, charger and essentials for babies or pets if already accessible. Avoid bulky possessions and delay. Wear long trousers, a long-sleeved top and enclosed footwear if recommended and available. Do not drive through barriers or a visible release plume.
Shelters may have differing policies for pets. Ask local emergency management which facilities can receive them, but do not delay human evacuation to solve every pet logistics question. Bring animals only when safe; if someone remains behind or a pet cannot be collected, tell responders.
If a child is at school and already sheltered under official instructions, do not enter a restricted evacuation corridor to collect the child. Contact the school through its authorised channel and follow incident guidance. The safest reunion may occur once emergency operations have stabilised.
What to do if the chemical is already on your skin or clothes
CDC instructs people exposed to a chemical release to get away from the area, remove contaminated material and get clean as quickly as possible. When feasible, undress and shower promptly, ideally within the first ten minutes, following the actual official guidance for the chemical. Removing contaminated outer clothes can remove much of the material.
Keep contaminated clothing separate from clean belongings and other people. Avoid pulling contaminated garments over the face if a safer method of removal is available. Do not handle another person’s contaminated clothing without appropriate protection. A responder may direct you to a specific decontamination site.
Do not add bleach, acids, alkalis or another chemical to an unknown substance in an attempt to neutralise it. Some chemicals require special decontamination procedures, so follow responders or Poison Control if you know or suspect a specific substance.
If a chemical reaches your eyes or causes burning, obtain urgent guidance from emergency personnel or Poison Control. Report what happened, the approximate time, any product label or name already known, and current symptoms. Do not rub an irritated eye or insert contact lenses to check whether vision improves.
After decontamination, medical evaluation may still be necessary because some effects arise from inhalation or delayed injury. A lack of obvious skin irritation does not rule out exposure.
When to call 911 and when to call Poison Control
Call 911 for severe breathing difficulty, collapse, seizures, major burns, an immediate rescue need or other life-threatening symptoms. State the incident location, what type of exposure is suspected, how many people are affected and whether they have been removed from the release area.
The US Poison Control number is 1-800-222-1222. It provides guidance for possible poisoning or toxic exposure. CDC lists Poison Control, 911 and hospital care as potential routes to help depending on the circumstances. Do not use an ordinary telephone consultation to delay emergency response when somebody is severely ill.
Report only what is known: whether there was a cloud, liquid splash, eye exposure or inhalation, whether clothing was contaminated, and symptoms such as coughing or dizziness. A guess based on an online photograph can mislead responders. The exact chemical may be determined by the fire department or hazardous-materials specialists.
If an animal has been exposed, keep yourself safe and ask a veterinarian or relevant emergency authority for advice. Do not bring a contaminated pet into a clean shelter room without following the decontamination instructions available for that situation.
If the incident happened on a road or railway near your home
A vehicle accident or train derailment may involve multiple hazardous materials, fire or mechanical hazards. Do not walk to the roadside to inspect placards or identify a tanker. Emergency responders need space, and wind or slope may carry a plume unpredictably.
If you are driving nearby and see a hazardous spill, stay out of a closed road or visible release area. Follow police traffic control rather than stopping to film. A car is not airtight and may not offer suitable shelter. CDC expressly warns that ordinary vehicles can be inadequate during chemical shelter-in-place emergencies.
If your home is directly adjacent to a closed road, confirm whether the authorities want residents to shelter or move. The release may affect your own road differently from one several blocks away. Avoid speculative messages stating that a particular school or bridge is “definitely safe.”
Children, schools, older adults and disabilities
Children may be tempted to look out a window or go outside to see a dramatic cloud. Explain that the safest immediate activity is staying in the designated room and following adults. Keep infants’ feeding supplies, appropriate medicines and an adult supervisor in the shelter.
Older adults, people who need mobility assistance, people with asthma and those who require medical devices may face particular difficulties. Make an individual plan before an incident: access to an appropriate room, medicines, communications and help if evacuation is later directed. Report specific medical needs when calling emergency services.
For schools, care homes and workplaces, shelter protocols should identify who closes ventilation, who verifies attendance, who communicates with emergency authorities, and when an evacuation route can be used. An individual teacher should not override a fire-service order because a family member demands pickup.
A person with communication impairments may need accessible alerts and direct assistance. Some local agencies provide text or other accessible emergency channels, but availability varies. Review local options before an incident and keep a backup means of contacting a trusted helper.
Can an N95 mask protect against a chemical gas?
Do not assume so. An N95-type particulate respirator is designed to filter certain airborne particles, not every gas or vapour involved in a chemical release. A mask that helps with smoke dust is not permission to enter a toxic plume or disregard evacuation orders.
Respirator selection for industrial chemicals depends on identifying the substance, concentration and oxygen conditions and requires appropriate equipment and training. The public should prioritise getting to the appropriate safe place and following official instructions, not purchasing an improvised mask during an emergency.
Avoid social-media advice suggesting a wet towel, perfume, essential oils or household chemicals can make a toxic gas harmless. These do not replace protection or professional assessment.
What if the smell disappears or the plume looks lighter?
Do not assume the danger has ended. An invisible chemical may remain present, a wind shift can bring more contaminated air, or responders may still be monitoring the scene. Only the responsible authorities can decide when a shelter order or evacuation restriction can be lifted.
When an all-clear is issued, officials may provide instructions about opening windows, changing ventilation filters, cleaning contaminated objects, accessing drinking water or returning to a building. Follow those directions rather than resuming normal activities immediately.
If authorities have directed decontamination, do not re-enter the home with contaminated clothing simply because the general shelter order has ended. Follow the specific sequence provided by responders.
Common situations and the safest decision
A truck spills an unknown liquid on a road beside your block
Stay away and notify emergency services if the spill is not already being handled. Check official local instructions. If authorities order sheltering, enter a safe room and isolate outside air as directed. Do not step outside to photograph the liquid.
A train derailment produces a visible cloud several kilometres away
A cloud’s appearance does not establish which side of town is safe. Follow fire and local emergency alerts for your address. Evacuate only using an authorised route if ordered, or shelter indoors if instructed.
A child comes indoors after touching an unknown chemical puddle
Keep other people away from the material. Follow CDC advice to remove contaminated clothing and get clean, accounting for the possibility that the substance may need special handling. Contact Poison Control or 911 according to symptoms and official instructions.
A resident feels dizzy during a shelter-in-place order
Keep the person away from possible contamination and contact emergency medical services or Poison Control promptly, depending on severity. Tell the dispatcher the location and active shelter instructions. Do not ignore serious symptoms simply because your building has closed its windows.
The mistakes to avoid
- Do not assume every release calls for evacuation. Some incidents are safer to shelter through.
- Do not ignore an evacuation order because indoor air currently smells normal.
- Do not turn on outside-air ventilation while ordered to seal the home.
- Do not use a car as a guaranteed airtight shelter.
- Do not drive into the plume to collect a child who is already safely sheltered elsewhere.
- Do not use household products to neutralise unknown chemicals on skin or clothing.
- Do not assume an N95 protects against all gases.
- Do not use a social-media photograph to identify an unknown release.
- Do not return before an official all-clear.
- Do not let pets, children or curious spectators approach contaminated ground.
Prepare before an industrial or transportation emergency
- Sign up for local emergency alerts and know your county or city’s official emergency website.
- Identify a suitable indoor chemical shelter room and how to isolate outdoor-air intake.
- Keep pre-cut plastic sheets, tape, towels and scissors if recommended for your building.
- Maintain a household go-kit with medications, water, phone power and essential documents.
- Keep a separate pet plan and necessary supplies.
- Agree how the family will communicate if school and home are in different alert zones.
- Review accessible evacuation requirements for anyone with limited mobility or medical equipment.
- Save 911 and Poison Control 1-800-222-1222.
- Understand the difference between sheltering in place and evacuation.
- Practise following an official alert without going outside to investigate.
Frequently asked questions
Should I leave my house if there is a chemical spill nearby?
Follow local emergency instructions. CDC says some chemical emergencies require sheltering in place, while others require evacuation. The safest choice depends on the actual release.
What room should I use during a chemical shelter order?
CDC generally recommends a room that can be sealed from outside air, with few windows, at a high level where practical, and with water access, unless local authorities provide more specific guidance.
Should I turn on the air conditioner?
If ordered to shelter in place, follow official instructions about turning off systems that bring outdoor air indoors. Do not create a separate medical or building hazard while doing so.
Is a cloth mask or N95 enough protection?
No. A particulate mask does not necessarily protect from chemical gases and vapours. Do not use it to enter the release area.
What should I do if chemical material gets on me?
Move away from the source and follow CDC and responder decontamination guidance; promptly remove contaminated clothing and wash or shower where appropriate, then seek medical or Poison Control advice.
What is the US poison assistance number?
1-800-222-1222. For severe symptoms or immediate danger, call 911.
When is it safe to open the windows again?
When local authorities issue the all-clear and any ventilation instructions. Do not judge solely by the disappearance of smell or visible clouds.
The decision sequence to remember
Get away from the release. Follow the official SHELTER or EVACUATE instruction. Keep contaminated material away from the body and clean it off safely. Call 911 or Poison Control when needed. Wait for the all-clear.
Related survival guide: What to Do When You Smell Gas at Home in Great Britain.
Official US sources
- CDC — What to Do in a Chemical Emergency, updated July 2026
- CDC — Sheltering in Place for a Chemical Emergency, June 2026
- CDC — Evacuating During a Chemical Emergency
- CDC — Getting Clean After Chemical Exposure
- Poison Control — Get help for possible poisoning
Independent public-safety guide. Reviewed 6 November 2026. The actual local incident, chemical and emergency orders determine the safest actions.