Adult: 5,000 Millirems. The current federal occupational limit of exposure per year for an adult (the limit for a worker using radiation) is "as low as reasonably achievable; however, not to exceed 5,000 millirems" above the 300+ millirems of natural sources of radiation and any medical radiation.
Although radiation affects different people in different ways, it is generally believed that humans exposed to about 500 rem of radiation all at once will likely die without medical treatment.
500 - 1,000 mSv received in a short period will likely cause some observable health effects and received over a long period will increase your chances of getting cancer. Above 500 mSv we may see some changes in blood cells, but the blood system quickly recovers.
Radiation levels and their effects
Above 1000 mSv, severity of illness increases with dose. If doses greater than 1000 mSv occur over a long period they are less likely to have early health effects but they create a definite risk that cancer will develop many years later.
Levels of radiation at Chernobyl. The radiation levels in the worst-hit areas of the reactor building, including the control room, have been estimated at 300Sv/hr, (300,000mSv/hr) providing a fatal dose in just over a minute.
Gamma rays are the most harmful external hazard. Beta particles can partially penetrate skin, causing “beta burns”. Alpha particles cannot penetrate intact skin. Gamma and x-rays can pass through a person damaging cells in their path.
Whole body doses between 4000 mGy and 5000 mGv within a short time frame would kill 50% of those exposed, with 8000-10,000 mGy universally fatal. The doses received by the firefighters who died were estimated to range up to 20,000 mGy.
Cell phones emit radiation in the radiofrequency region of the electromagnetic spectrum. Second-, third-, and fourth-generation cell phones (2G, 3G, 4G) emit radiofrequency in the frequency range of 0.7–2.7 GHz. Fifth-generation (5G) cell phones are anticipated to use the frequency spectrum up to 80 GHz.
Is it bad to sleep with your phone beside you? Yes, usually speaking, it's not a good idea to sleep with your phone nearby. Sleep quality may suffer if you keep your phone close to your head while trying to slumber because it emits electromagnetic radiation.
X-Rays-single exposure
Medical procedures account for nearly all (96%) human exposure to man-made radiation. For example, a chest x-ray typically gives a dose of about 0.01 rem (10 millirem) and a full-body CT gives a dose of 1 rem (1,000 mrem), as shown in the table to the left.
Keep your cell phone at least 3 feet away from your bed to limit radio frequency exposure. Turn your cell phone off before you go to bed (if you don't rely on your phone's alarm clock)
How long can you stay in the Chernobyl Exclusion Zone? There are two exclusion zones in Chernobyl; a 10km inner and 30km outer Exclusion Zone. It is safe to stay in the outer Exclusion Zone overnight.
The official death toll directly attributed to Chernobyl that is recognized by the international community is just 31 people with the UN saying it could be 50. However, hundreds of thousands of “liquidators” were sent in to put out the fire at the nuclear power plant and clean up the Chernobyl site afterwards.
Chernobyl had a higher death toll than Fukushima
While evaluating the human cost of a nuclear disaster is a difficult task, the scientific consensus is that Chernobyl outranks its counterparts as the most damaging nuclear accident the world has ever seen.
On the morning of Sept. 30, 1999, at a nuclear fuel-processing plant in Tokaimura, Japan, 35-year-old Hisashi Ouchi and two other workers were purifying uranium oxide to make fuel rods for a research reactor.
Gamma rays are the strongest from of radiation.
Hisashi Ouchi Suffered History's Worst Radiation Burns — Then Doctors Kept Him Alive For 83 Excruciating Days Against His Will.
How large an area was affected by the radioactive fallout? Some 150,000 square kilometres in Belarus, Russia and Ukraine are contaminated and stretch northward of the plant site as far as 500 kilometres. An area spanning 30 kilometres around the plant is considered the “exclusion zone” and is essentially uninhabited.
When Will Chernobyl Be Safe? With that being said, the most dangerous place to be in Chernobyl is anywhere near the reactor - that area will take at least 20,000 years to disperse as far as radiation breakdown. Many will ask, "then how is it safe for tours to happen at Pripyat?"
Today, the Exclusion Zone is one of the most radioactively contaminated areas in the world and draws significant scientific interest for the high levels of radiation exposure in the environment, as well as increasing interest from tourists.
Current status. According to a report by the Worldwatch Institute on nuclear waste, Karachay is the most polluted (open-air) place on Earth from a radiological point of view.
Chernobyl animals are mutants ...
Scientists have noted significant genetic changes in organisms affected by the disaster: According to a 2011 study in Biological Conservation, Chernobyl-caused genetic mutations in plants and animals increased by a factor of 20.
While it naturally fades over time, this can sometimes take thousands of years. Scientists have previously said, due to the huge amount of contamination in the Chernobyl area, the exclusion zone will not be habitable for many, many years.
Don't charge any electrical devices, including phones and tablets, on your bed or under your pillow while you sleep as they could overheat and cause a fire. If possible, avoid charging devices unattended or overnight, and when necessary only charge them on a hard surface such as a desk.
Mistake: Sleeping with your cell phone
Cell phones pump out electromagnetic radiation whenever they're on - which means sleeping with one nearby boosts your exposure all night long. What to do? Put the phone on "airplane mode" (which shuts down the transceiver) or turn it off.