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Here's Something To Think About...

Pick two places to meet after an emergency situation. One should be right outside your home and the other outside your neighborhood.

Frequently Asked Questions

Below are the answers to many frequently asked questions the Department of Homeland Security has received in response to information provided on We hope you find the additional information below helpful. Please note that these questions are designed to supplement information on, so please be sure to consult that guidance first.

Most importantly, as you consider family preparedness, we urge you to remember that the best thing you and your family can do during an emergency is to listen to messages from your local emergency managers, broadcast on radio or television. They will tell you when to shelter-in-place and when to leave the area. They will provide you with the best ways to protect yourself and your family. With that information, and the preparedness information provided on, you will be better able to take appropriate action quickly and decisively.

What type of event would require sheltering-in-place?

  • Emergency officials would likely advise individuals to shelter-in-place when the chemical is expected to dissipate in a short time period, there is not time to evacuate, or chemical fumes could quickly overtake you if you do not seek shelter immediately.
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Can you really shelter-in-place?

  • Studies have shown that taking steps to temporary seal off a room using common materials enhances the safety of a room against the impact of a chemical plume.
  • The temporary shelter created by a shelter-in-place room definitely provides more protection than basic sheltering, i.e. going indoors, closing windows and doors and shutting off HVAC systems.
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What room should you choose to shelter-in-place?

  • You should take into account which room will be the quickest room to seal in order to prevent chemicals from entering the area.
  • People often select a bathroom as they often are located in the interior of a home and tend to have few, if any windows. They also allow for the use of facilities while sheltering-in-place.
  • Other rooms that may be appropriate include other interior rooms, rooms with one small window, or rooms with no exterior doors.
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What room should we use if we don't have a room without windows?

  • The best room is the room with the fewest windows and doors. Since each opening will require time to seal it off, minimizing the number that you will need to seal will shorten the time it takes to reduce airflow into the room.
  • The room should be easy to get to and provide adequate space for family members.
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Why does the government recommend duct tape and plastic sheeting?

  • The items can be used to "shelter-in-place," creating a room with reduced air infiltration of chemical agents into an area.
  • They are resistant to permeation from chemical agents.
  • They provide the ability to rapidly exit from a temporary shelter-in-place once the plume has passed.
  • The items are readily available for the general public.
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Is there a particular type (brand) of duct tape that citizens should buy?

  • DHS recommends using duct tape with a minimum thickness of 10 mil (0.01 in).
  • DHS does not recommend particular brands.
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Can you use other types of tape?

  • If you do not have duct tape, any tape that will help seal off a room and hold down the plastic sheeting can be used.
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What is the most effective type of plastic sheeting?

  • DHS recommends using plastic sheeting with a thickness of 4 to 6 mil (0.004 in. - 0.006 in.) or greater.
  • For reference, commercially available sheeting is typically sold at 0.7, 1, 1.2, 1.5, 2, 2.5, 3, 4, 6 and 10 mil.
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Can you use garbage bags instead of plastic sheeting?

  • DHS does not recommend using plastic garbage bags instead of plastic sheeting as the thickness of the plastic is below the recommended 4 to 6 mil thickness.
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Will shrink-wrap plastic used for weatherproofing work?

  • DHS does not recommend using shrink-wrap plastic.
  • The double-faced tape to secure the shrink-wrap in place has not been tested with chemical agents.
  • Installing shrink-wrap plastic would take more time than using plastic sheeting and duct tape, due to the two steps required (adhesion to the frame using double sided tape and use of hair dryer to achieve a tight fit).
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Do these precautions work? How safe will we be? How effective is taping and sealing a room?

  • Studies have show that using duct tape and plastic sheeting to shelter-in-place during a chemical or biological attack provides additional protection to people sheltering-in-place beyond that provided for by the structure of the house alone.
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Is it 100% guaranteed to work?

  • While it isn't considered guaranteed, studies have shown that using duct tape and plastic sheeting to shelter-in-place during a chemical or biological attack provides additional protection to people sheltering in place beyond that provided for by the structure of the house alone.
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What is the science behind the recommendation to seal off rooms?

  • Duct tape was tested as part of a study on chemical protective clothing materials.
  • In this study, it was concluded that duct tape provided at least a temporary seal against permeation by stimulants of common chemical agents, including GB, VX, mustard and pesticides.
  • Depending on the chemical agent, duct tape resisted permeation by a liquid agent for 3 hours to more than 24 hours.
  • The study tested duct tape of 10 mil (0.01 in.) thickness.
  • Plastic sheeting was tested as part of a test using live chemical warfare agents conducted at the Chemical Defense Establishment in Porton Down, England in 1970.
  • Agents tested included H and VX. Varying thickness were tested, including 2.5 mil (0.0025 in.), 4 mil (0.004 in.), 10 mil (0.01 in.) and 20 mil (0.02 in.).
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When should someone evacuate versus sheltering-in-place?

  • Local officials are the best source of information when determining whether to evacuate or shelter-in-place.
  • In the event of an emergency, individuals should listen to their radios and follow the directions of the emergency officials.
  • In general, sheltering-in-place is appropriate when conditions require that you seek immediate protection in your home, place of employment, school or other location when disaster strikes.
  • People should take steps to prepare in advance in case local officials direct you to evacuate. This includes having a disaster supply kit that is portable and can be taken with you.
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What should be taped and sealed in the room I choose?

  • Individuals should precut plastic to fit over the entire openings of windows and doors, including the frames. In addition, plastic should be cut to cover vents and ventilation fans.
  • Cut the plastic a minimum of 6" wider than the opening. This will make it easier to put up the sheets if needed.
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Do I need to disconnect water lines in order to tape over the opening?

  • No, you do not need to disconnect water lines. However, you should make sure that the area where the pipe comes through the wall is properly sealed to eliminate airflow with an appropriate sealant such as caulk.
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Do I need to tape over drains and faucets if I use my bathroom?

  • You do not need to tape drains or faucet openings. However, you should seal around water pipes coming through the wall into the room. This can be done in advance with caulk or other appropriate material to eliminate any air leaks.
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Should I cover the dryer vent to the outside?

  • You should cover any opening from the room. This includes a dryer vent if there is a washer/dryer located in your shelter-in-place room.
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How long can a family stay in a sealed room? Will we run out of air to breathe?

  • DHS recommends that individuals allow ten square feet of floor space per person in order to provide sufficient air to prevent carbon dioxide build up for up to 5 hours assuming a normal breathing rate while resting.
  • Many chemical releases would be diluted within a few hours, so the direction to shelter-in-place would likely be made for a short time period while a chemical cloud dissipates.
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If we bring plants into our shelter-in-place room will we be able to stay in the room longer if needed?

  • Bringing plants into the shelter-in-place room will not extend the time you can stay in the room.
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Should I seal up the room ahead of time?

  • DHS recommends that you precut plastic sheeting for any windows, doors, vents or openings and label them appropriately.
  • The plastic should then be stored with duct tape and scissors in the designated shelter-in-place room so that it can be quickly accessed and installed.
  • DHS does not recommend that you install the plastic sheeting in advance.
  • You can, however, make sure that any areas that can be permanently sealed such as where pipes come out of the wall or where trim meets the floor and walls, are properly caulked. This will also help reduce heating and cooling costs so is a good idea overall.
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Should I seal my whole house?

  • No, you are better off moving quickly to a designated shelter-in-place room and seal the room to reduce air flow from the outside into the room.
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Is using wet towels over your mouth or at the bottom of doors and windows effective?

  • You should cover your mouth and nose while seeking shelter, but it should not be relied on as a safety measure in place of getting to shelter immediately. Covering your mouth does not prevent exposure to chemical vapors, however it is effective for smoke and for aerosols (such as would be released in the immediate area of a biological attack).
  • In studies, using a dry folded handkerchief was the most effective filter for particulates or aerosols.
  • Using wet material such as a towel or handkerchief actually reduced the effectiveness or filtering from vapors. In addition, wet materials are more difficult to breathe through.
  • Placing a wet towel at the bottom of a door or window provides no protection against vapors entering a room.
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Can you use fans in a room after you seal it off?

  • The purpose of shutting off your home's furnace, air conditioning and fans is to reduce the airflow from the outside to the inside of your home.
  • Operating a fan within a sealed room will not bring air inside and, as such, can be used. Take precautions though, so that the fan does not affect the seals that prevent air from entering the room.
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Why do you shelter above ground for a chemical and biological attack vs. below ground for a radiological or nuclear attack? What floor of the house should the shelter-in-place room be located on?

  • In a chemical attack, the contaminants are typically distributed in an aerosol that is heavier than air near the release of the chemical. As such, it will settle to the ground.
  • However, as the vapor plume is carried down wind, the concern about settling in low-lying areas is reduced.
  • With this in mind, the best room for sheltering-in-place is the room that is the most convenient for your family to quickly get to and seal that is large enough to provide appropriate air for several hours.
  • With regards to a radiological or nuclear attack, the more shielding, distance and time you can take advantage of after such an attack, the less exposure you will face.
  • The additional distance from the blast of a nuclear weapon provided by being below ground also offers an increased level of protection.
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Can we shelter-in-place using a whole basement? Is the basement dangerous because the vapors will settle in low areas of the house?

  • If your basement offers the easiest location to tape and seal all windows and doors, then it may be the best location for your family even though it is below ground.
  • Since each opening will require time to seal it off, minimizing the number that you will need to seal will shorten the time it takes to reduce airflow into the room.
  • The room should be easy to get to and provide adequate space for family members.
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What should I do when the plume has passed by? How long will I need to/How long should I stay in the shelter-in-place room?

  • You should remain in your sealed room until local authorities notify you that it is safe. Pay close attention to all official warnings and instructions to proceed.
  • You should include a battery-powered radio with extra batteries in your emergency supply kit that you store in your shelter-in-place room for this purpose.
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Will my house be contaminated with chemicals?

  • If the plume passed over your house there is a potential for contamination, especially to fabrics, carpets, and other materials, although it is unlikely to pose a significant threat. Local officials will advise you if your house is safe and what actions to take after a chemical emergency.
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Is it safe to touch objects in the house? Outside the house?

  • Unless there was contamination by a liquid form of the chemical, objects in or out of the house should not pose a significant health risk, however one should take precaution and not touch or handle items or surfaces that were potentially exposed to the vapor cloud, especially outside the house.
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Why do you recommend having three days worth of supplies if you'll only be sheltering for a short time?

  • Disasters can sometimes make it unsafe for people to leave their residence for a period after the disaster hits.
  • The need for long-term sheltering-in-place, e.g. having a three-day supply of food and water, is important for families preparing for emergencies where supplies to stores, electricity and water are disrupted.
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What should I do if I'm outdoors when a chemical attack occurs?

  • If the release is outdoors and you are near the contaminated area, seek shelter inside a building.
  • If you are not in the contaminated area, move away from suspected areas of contamination and avoid moving downwind of the area of the attack.
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What should I do if I'm not at home when a chemical attack occurs?

  • If you are indoors and the release is outdoors, shelter-in-place in your location until notified by authorities that it is safe to leave the building.
  • If you are indoors and the release is in your building - go outside if you can avoid passing through contaminated areas. Otherwise, go to your shelter-in-place location or move as far away from the contaminated area as possible.
  • As in all emergencies, follow instructions from local emergency officials to determine when it is safe to evacuate.
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What if I can't get to a shelter-in-place location that can be sealed?

  • Move quickly to a small room with the least amount of windows and outdoor walls. Use any material in the area to block air from easily flowing into the room. This can include packing tape, rugs, plastic bags, newspaper or clothing. These are not the preferred materials for sealing a room, but would be better than no protective measures.
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What should I do if I'm in my car when a chemical attack occurs?

  • If you are in a car and are not in the immediate contaminated area, close windows, turn off vents and drive away from the area. Avoid going downwind of the area.
  • If you are in the contaminated area, seek shelter immediately. If you cannot get into a building to shelter, stay in your car with the windows rolled up, engine off, and vents closed.
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What should I do if I've been exposed to a chemical attack?

  • Remove all clothing and other items in contact with the body. Cut contaminated clothing off that needs to be removed over the head to avoid contact with eyes, nose and mouth. If possible, put contaminated items in a plastic bag and seal.
  • Wash hands thoroughly with soap and water.
  • Remove contacts or glasses. Put glasses in a pan of household bleach to decontaminate. Flush eyes with lots of water.
  • Gently wash face and hair with soap and water and thoroughly rinse with water.
  • Decontaminate area of the body likely to have been contaminated. Blot - do not swab or scrape) with a cloth soaked in soapy water and rinse with clear water. Change into uncontaminated clothes.
  • Listen to local authorities for specific instructions.
  • If possible, proceed to a medical facility for screening.
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How can I help those who have been exposed to a chemical attack?

  • Help them through the steps outlined above, using extreme caution not to expose yourself to the chemical agent.
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What does the government recommend as to the use of gas masks or protective hoods? Why doesn't DHS include information on gas masks and hoods as part of its recommendations?

  • The use of gas masks and hoods by the public during a chemical threat is not recommended due to legitimate safety concerns.
  • Improper use of masks and hoods as well as a false sense of security as to their effectiveness could pose a threat to public safety.
  • For example, it is difficult to obtain a proper seal with the mask if you have facial hair such as a beard or long sideburns.
  • Protective masks do not fit small children.
Note: Studies are ongoing and technology is evolving in the area of protective masks and hoods. We will continue to update the public as new products and information become available.

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