But none match the specter of a nuclear explosion.
A small nuclear weapon on the ground can create a stadium-size fireball, unleash a city-crippling blastwave, and sprinkle radioactive fallout hundreds of miles away.
The good news is that the Cold War is over and a limited nuclear strike or a terrorist attack can be survivable (a direct hit notwithstanding).
The bad news: A new arms race is likely underway – and one that may add small, portable nuclear weapons to the global stockpile. Lawmakers and experts fear such "tactical" or battlefield-ready devices (and their parts) may be easier for terrorists to obtain via theft or sale.
"Terrorist use of an actual nuclear bomb is a low-probability event – but the immensity of the consequences means that even a small chance is enough to justify an intensive effort to reduce the risk," the Bulletin of the Atomic Scientists said in a September 2017 article, which outlines what might happen after terrorists detonate a crude device that yields a 10-kiloton, near-Hiroshima-size explosion in a city.
A nuclear terrorist attack of this magnitude is one of 15 major disaster scenarios planned for by FEMA and other US agencies. (The same scenario also includes a dirty bomb explosion, though such an event would be dramatically less harmful.)
As part of the planning effort, the Environmental Protection Agency maintains a series of manuals about how state and local governments should respond.
A companion document anticipates 99 likely questions during a radiation emergency – and scripted messages that officials can copy or adapt.
"Ideally, these messages never will be needed," the EPA says in its messaging document. "[N]evertheless, we have a responsibility to be prepared to empower the public by effectively communicating how people can protect themselves and their families in the event of a radiological or nuclear emergency."
Here are a handful of the questions the EPA anticipates in the event of a nuclear emergency, parts of statements you might hear or see in response, and why officials would say them.
"What will happen to people in the affected neighbourhoods?"
What they will say: "As appropriate: Lives have been lost, people have been injured, and homes and businesses have been destroyed. All levels of government are coordinating their efforts to do everything possible to help the people affected by this emergency.
As lifesaving activities continue, follow the instructions from emergency responders… The instructions are based on the best information we have right now; the instructions will be updated as more information becomes available."
Why: The worst thing to do in an emergency is panic, make rash decisions, and endanger your life and the lives of others. However, it's also incumbent on officials to be truthful. The first messages will aim to keep people calm yet informed and as safe as possible.
"What is radioactive material?"
What they will say: "Radioactive material is a substance that gives off radiation in the form of energy waves or energised particles."
Why: Nuclear bombs split countless atoms in an instant to unleash a terrifying amount of energy. About 15 percent of the energy is nuclear radiation, and too much exposure can damage the body's cells and healing ability, leading to a life-threatening condition called acute radiation sickness.
Without advanced warning, people can do little about the energy waves, also called gamma radiation, which are invisible and travel at light-speed.
But the energised particles – including radioactive fission products or fallout – travel more slowly, giving people time to seek shelter. The particles can also be washed off.
"Where is the radioactive material located?"
What they will say: "Radiation and environmental health experts are checking air, water and ground conditions in and around the release site to locate the areas with radioactive contamination."
"Stay tuned to radio or television, or visit [INSERT AGENCY WEBSITE HERE] for the latest information."
Why: If a nuclear bomb goes off near the ground (which is likely in a terrorist attack), the explosion will suck up debris, irradiate it, and spread it around as fallout.
Some of this material rapidly decays, emitting gamma and other forms of radiation in the process.
Fallout is most concentrated near a blast site. However, hot air from a nuclear fireball pushes finer-grade material high into the atmosphere, where strong winds can blow it more than 100 miles (161 km) away.
It may take days for radiation workers to track where all of it went, to what extent, and which food and water supplies it possibly contaminated.
"If I am in a car or truck, what steps should I take to protect myself and my loved ones?"
What they will say: "Cars and trucks provide little protection from radiation… Shut the windows and vents… Cover your nose and mouth… Go inside and stay inside… Tune in."
Why: Movies portray cars as protective cocoons and rapid escape vessels in emergencies. But after a nuclear blast they will likely become death traps.
Vehicles don't have nearly enough metal to meaningfully absorb radiation. You also won't be able to outrun the danger, as fallout can travel at speeds of 100 mph (161 km/h) in the upper atmosphere. Roads will also be choked with panicked drivers, accidents, blocked streets, and debris.
If you're already in a car, find a safe place to pull it off the road, get out, and make a dash for the nearest building. Tuning in with a radio will help you listen for instructions on how, when, and where to evacuate a dangerous area to a shelter.
"If I am outside, what steps should I take to protect myself and my loved ones?"
What they will say: "Cover your nose and mouth… Don't touch objects or debris related to the release… Go inside and stay inside."
Why: Being outside is a bad place to be, since fallout sprinkles everywhere and can stick to your skin and clothes. Less fallout gets indoors, and materials like concrete, metal, and soil (e.g. in a basement) can block a lot of radiation from the stuff that sprinkles outside.
"If I am inside a building, what steps should I take to protect myself and my loved ones?"
What they will say: "Stay inside. If the walls and windows of the building are not broken, stay in the building and don't leave… If the walls and windows of the building are broken, go to an inside room and don't leave. If the building has been heavily damaged, quickly go into another building… Close doors and windows."
Why: The blastwave from a nuclear explosion can shatter windows for miles – and fallout can blow around, hence the need to contain yourself away from exposed areas. Be prepared to hunker down for up to 48 hours, as that's roughly how long it takes the most dangerous fallout radiation to dissipate.
"Is the air safe to breathe?"
What they will say: "Federal, state and local partners are monitoring [AREA] to determine the location and levels of radioactive material on the ground and in the air."
Why: There could be radioactive smoke and fallout in the air, but not breathing isn't really an option. To reduce your exposure risk, stay inside, shut the doors, and close the windows.
Turn off fans and air conditioners, or set them on recirculate. If you're outdoors, cover your nose and mouth and get inside a building as soon as possible.
"If people are told by health and emergency management officials to self-decontaminate, what does this mean?"
What they will say: "[T]ake several easy steps to remove any radioactive material that might have fallen onto clothes, skin or hair…. Remove your outer clothes… Wash off… If you cannot shower, use a wet wipe or clean wet cloth to wipe any skin that was not covered by clothing… Gently blow your nose and gently wipe your eyelids, eyelashes and ears with a clean wet cloth… Put on clean clothes… Tune in."
Why: Fallout continues to expose you to harmful radiation if it's stuck to you or inside your body. Anything that might be contaminated should be slipped into plastic bags, sealed off, and chucked outside (or as far away as possible from people).
Showering with a lot of soap can remove most fallout, but avoid conditioner – it can cause fallout to stick to your hair.
"What should I do about my children and family? Should I leave to find my children?"
What they will say: "If your children or family are with you, stay together. If your children or family are in another home or building, they should stay there until you are told it is safe to travel. You also should stay where you are… Schools have emergency plans and shelters."
Why: Every parent's instinct will scream to reconnect with his or her family, but patience is the best move. If you go outside, you'll risk exposure to radioactive fallout and other dangers, as the route may be perilous or even impassable.
Most importantly, it's hard to help your family after the dust settles if you are injured – or worse.
"Is it safe for me to let someone who might have been affected by the radiological incident into my home?"
What they will say: "If someone has radioactive dust on their clothes or body, a few simple steps can clean up or decontaminate the person."
Why: You can offer safe shelter to people caught outside – just have them decontaminate themselves as quickly as possible. This will protect everyone by keeping radioactive fallout at bay.
Have them remove and bag up their outer clothes, then take a shower with lots of soap and shampoo (or perform a thorough wipe-down).
"How do I decontaminate my pet?"
What they will say: "If you are instructed to stay inside, your pets should be inside too. If your pet was outside at the time of the incident, the pet can be brought inside and decontaminated."
Why: Pets, like people, can be contaminated by fallout and bring it indoors. This can endanger them and you.
To decontaminate your pet, cover your nose and mouth, put on gloves, and then wash your pet in a shower or bath with a lot of shampoo or soap and water.
Rinse your pet thoroughly and take a shower yourself afterward.
"When should I take potassium iodide?"
What they will say: "Never take potassium iodide (KI) or give it to others unless you have been specifically advised to do so by public health officials, emergency management officials, or your doctor."
Why: KI pills are among the last things people need immediately after a nuclear blast and aren't worth a mad dash to a pharmacy during the disaster, according to Brooke Buddemeier, a health physicist and radiation expert at Lawrence Livermore National Laboratory.
"Most people seem to think of the potassium iodide, or KI, pills as some type of anti-radiation drug. They are not," Buddemeier previously told Business Insider.
"They are for preventing the uptake of radioiodine, which is one radionuclide out of thousands of radionuclides that are out there."
Radioiodine makes up about 0.2 percent of overall exposure. The pills are useful for longer-terms concerns about contaminated water and food supplies, and blocking radioiodine from concentrating in people's metabolism-regulating thyroid glands.
"Is taking large amounts of iodized salt a good substitute for potassium iodide?"
What they will say: "No. Iodized salt will not protect your thyroid."
Why: Table salt, or sodium chloride, has some iodine added in to prevent deficiencies that lead to conditions like goiter.
But the amount of iodine in table salt is trivial, and eating even a tablespoon or so is a great way to throw up any useful iodine.
"Is the water safe to use?"
What they will say: "[U]ntil we have drinking water test results, only bottled water is certain to be free of contamination. Tap or well water can be used for cleaning yourself and your food… Boiling tap water does not get rid of radioactive material."
Why: Radioactive fallout can dissolve into or remain suspended in water, just like salt or dust.
That's not good, since radioactive particles can do more harm inside of your body than outside of it. Bottled water gets around this problem – though you do need to wipe containers down in case they have been dusted with fallout.
"Is the food safe to eat?"
What they will say: "Food in sealed containers (cans, bottles, boxes, etc.) and any unspoiled food in your refrigerator or freezer is safe to eat… Don't eat food that was outdoors from [TIME, DATE] in [AREA]."
Why: Food that isn't contained might have radioactive fallout in it. You'll need to wipe down cans, cookware, utensils, and anything else that might touch what goes into your mouth.
"Can people eat food from their gardens or locally-caught fish and game?"
What they will say: "People in [AREA] are instructed not to eat [FOOD FROM THEIR GARDENS, LOCAL FISH, LOCAL WILDLIFE]."
Why: Anything that's outside – fruit, vegetables, and animals included – may have radioactive fallout particles on or in them after a nearby nuclear blast.
Until the scope of contamination is known, food from outdoor sources should be considered potentially hazardous. Avoid food that could be been exposed to fallout. If that's not possible, wash it to try to rinse off as much contamination as possible.
"I am pregnant. Is my baby in danger?"
What they will say: "[M]ost radiation releases will not expose the foetus to levels high enough to cause harmful health effects or birth defects… Once dose levels to the expectant mother and foetus have been determined, your physician can consult with other medical and radiation professionals to identify potential risks (if any) and provide appropriate counseling."
Why: There are few things more terrifying for an expectant parent than thinking something could be wrong with the baby, but a foetus is somewhat protected from radiation by the uterus and placenta, according to the CDC.
A mother could still inhale or ingest radioactive fallout, though, so doctors will need to check the mother's abdomen to figure out a foetus's exposure. Once a dose is determined, it's possible to see if it's enough to cause any health effects, including birth defects.
"Is it safe to breastfeed?"
What they will say: "The nutritional and hydration benefits from breastfeeding far outweigh any risk from radiation."
Why: Fallout is again the main concern here: What goes into a mother can end up in her breast milk. Officials may encourage families to temporarily switch to formula and pump-and-dump milk (to keep production going during the emergency).
It's also a good idea to wipe down formula bottles and pumping equipment to minimise fallout contamination. But if no formula is available, depriving a baby of sustenance is the worst option.
"I am seeing a lot of information and instructions on Internet blogs about what to do. Should I follow that advice?"
What they will say: "Check official sources first. You can find the latest information at [INSERT WEBSITE HERE].
Blogs, social media and the Internet in general can provide useful information, but only if the source is known and trustworthy."
Why: Misinformation spreads rapidly in the aftermath of disasters, and some people may intentionally distribute rumours or false information.
It's best to stick to official websites, hotlines, TV, and radio broadcasts, and use multiple sources to verify information you're unsure about.
"How can the public help?'
What they will say: "Don't abandon your car… Don't go near the release site… Use text messaging… Don't go to the hospital, police stations or fire stations unless you have a medical emergency… Stay tuned…"
Why: In the aftermath of a nuclear disaster, the most helpful thing most people can do is to stay out of the way. This helps first responders get to people that need help.
Cars in the middle of the road slow down emergency vehicles, and going to the release or blast site is extremely perilous, at best.
Relying on text messages helps keep phone lines from overloading (and open to 911 calls), and limiting hospital visits to serious injuries or medical conditions helps free up resources for those who need the most aid.
This article was originally published by Business Insider.
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