It has long been known that many biblical scholars doubt that the stories written in the Old Testament are factual. The patriarchs, Abraham, Isaac and Jacob, didn’t exist, nor was there a man named Moses who, with his brother Aaron, led the Hebrew slaves out of Egypt, through a Wilderness for 40 years until they reached “The Promised Land.” Actually they doubt there ever was such an event as “The Exodus.”
These scholars are known as minimalists, and they have reams of arguments to prove that the biblical stories were created for political, religious, or literary reasons, or that they were simply myths. They also show that the texts were written by different hands at different times to finally form the books of the Bible, and that this final codification was accomplished at a much later time. But in the books of Exodus, Leviticus, and Numbers there are details, important details, that are difficult to overlook.
Referring to the Exodus of the Hebrews, the Bible reports that, when Moses left Egypt with his newly freed slaves, he did so at the behest, and under the guidance of, an all powerful presence who had earlier identified Himself to Moses as the Lord. The writings say that to continue with His guidance the Lord introduced a set of rules necessary for Him to communicate with Moses and Aaron. This communication was carried out in a portable tent and used throughout the Hebrews’ travels. The tent contained a gold-covered box, the Ark of the Covenant (otherwise known as the Ark of the Testimony), and communication was effected through a cloud which settled on the Ark. The Bible is specific when it speaks of the cloud’s presence:
“And the Lord said to Moses, ‘See I come to you in a thick cloud in order that the people may hear when I speak with you.’” (Exodus 19:9) … “…when Moses entered into the tent the pillar of cloud used to descend, and it stood at the door of the tent and He spoke with Moses…” (Exodus 33:9).
But early on there was a problem with this system. The Bible says that the cloud was dangerous:
“…And the Lord said to Moses, ‘Speak to Aaron your brother that he [does] not come at all times to the Holy Place [the sanctuary in the Tent] before the covering on the Ark that he doesn’t die, because in the cloud I will appear’…” (Leviticus 16:2).
There are many other references to the danger that is in the vicinity, and I explain them in detail and to the protections from them in Chapter 7 of my book Talking With God, but my only purpose here is to explain what happened relative to the age of the Bible.
To do this it’s necessary to answer the question “why was the cloud dangerous” and to get there we must turn to the Bible itself. First, what happens to a person who is exposed to the cloud? Upon exposure that person became a victim of what is translated a “plague of leprosy” (Hebrew nega tsaraath). These two Hebrew words actually indicate a sudden strike and stinging or burning, exactly what happens to the person when he or she gets burned. That exposed person would come to a priest who would make a diagnosis.
A detailed explanation of the symptoms, diagnosis, and treatment is laid out in Leviticus 13:2-46. If someone had visible changes in the skin or hair (such as rising patches or a bright spot), it indicated to the priest a possibility of a burn. If that flesh was raw and broken open, the person was unclean. If the burnt area changed to white, the person was clean. If the hair turned yellow and thin, then the person was unclean. When black hair grew in again, the person was clean. The burn could affect any part of the body or cover it completely. It could stay on the surface or penetrate deeper into the skin. Importantly, if the symptoms suggested the person was unclean, he or she was to be quarantined away from the community until they had recovered.
While the verses in Leviticus above explain the cloud’s effect on people, it could also be dangerous to inanimate things in a very marked way. 
Leviticus 14:34-48 explains that, after settlement in Canaan, the Israelites were to watch for plague appearing in their houses. The moment plague was spotted, manifesting as “hollow streaks, greenish or reddish, which in sight are lower than the wall” that house was to be quarantined and no one was allowed to enter for a week. If the plague spread, the affected section was to be removed and taken outside the city for disposal. If the same problem arose again, the priest would diagnose it as “fretting leprosy” and would mandate the destruction and disposal of the entire structure. Moreover, anyone entering the house would immediately become unclean, and those sleeping and eating in it (that is, the inhabitants), would have to wash their clothes.
It wasn’t only structures that could be affected, materials could be too. Leviticus 13:47-59 shows that garments could become “leprous” in the same manner as houses, requiring isolation of the garment and, if seriously affected, destruction by burning. Multiple washing was also required and, if the “plague” did not spread, the “leprous” area could be cut from the garment and disposed of.
Scholars have long considered the possibility that rather than a metaphysical malady, the conditions and contaminations described above (at least in people) might be related to diseases identified in the modern era. In 1873, Gerhard Henrik Armauer Hansen discovered a disease caused by a form of bacteria that came to be known by his name, Hansen’s Disease, which many claim was the biblical leprosy, although it didn’t exist at the time in the ancient Near East. Gregory Minh, an epidemiologist of the 19th century, studied what we term leprosy today extensively and established it to be contagious and therefore thought that it could not be a candidate for tsaraath. Reuven Kalisher and Yehuda L. Katzenelson echoed this idea, claiming that tsaraath was actually vitiligo, a long-term skin condition which makes patches of skin lose their pigment. As recently as 2016, dermatologists have been theorizing about the nature of tsaraath, claiming it could be everything from psoriasis to syphilis.
But is there anything in contemporary scientific literature that can offer us a more logical comparison to these symptoms in humans? A 106-page study entitled Some Effects of Ionizing Radiation on Human Beings begins thus:
“On March 1, 1954, an experimental thermonuclear device was exploded at the U. S. Atomic Energy Commission’s Eniwetok Proving Grounds in the Marshall Islands [see picture below]. Following the detonation, unexpected changes in the wind structure deposited radioactive materials on inhabited atolls.”  The radioactive material that floated over the various atolls, Rongelap, Ailinginae, Rongerik, and Utirik, contaminated the residents in varying degrees of intensity. Rongelap received the highest doses of radiation. About two-thirds of the people there “were nauseated during the first 2 days.”  On the most contaminated island, Rongelap, the fallout was described as a powdery material, which fell over a period of several hours and whitened the hair and adhered to the skin. “During the first 24–48 hours after exposure, about 25 percent of the Marshallese in the two higher exposure groups experienced itching and a burning sensation of the skin…these symptoms were present to a lesser extent in the Americans on Rongerik Atoll who were aware of the danger, took shelter in aluminum buildings, bathed and changed clothes. These precautions greatly reduced the subsequent development of skin lesions in this group.” 
Clearly, the act of bathing and changing clothes, along with the cover provided by the buildings, were instrumental measures for protecting the Americans from more severe exposure to radioactivity. These decontamination measures (of removing clothing and bathing) are amazingly spelled out in Leviticus 16:23-24 as instructions on how the priests are to wash themselves after exiting the tent where they were exposed to the cloud:
“Aaron shall come into the Tent of Meeting, and shall take off the linen garments which he put on when he went into the Holy Place, and shall leave them there. Then he shall bathe himself in water in a holy place, put on his garments…”
The construction of the Tabernacle itself also places the act of washing as central to survival. The bronze basin, placed between the Tent of Meeting and the altar was filled with water specifically for the priests to wash their hands and feet, so that “whenever they [the priests] enter the tent of meeting, they shall wash with water so that they will not die” (Exodus 30:20). In this instance, washing is directly related to remaining alive.
While the monograph on the Marshall Islands incident is a thorough study of the physiological aspects of radiation poisoning, I am most interested in the appearance of the skin lesions. As expected, the lesions varied in intensity depending on the amount of fallout. They developed mostly on exposed parts of the body not covered by clothing during the fallout. The majority of individuals developed many lesions, most of which were superficial. As to appearance, “in the early stages all lesions were characterized by hyperpigmented macules [discolored spots], papules [small elevations in the skin], or raised plaques [patches].” 
In the Rongelap group, 20% developed ulcerative lesions, which was more than on the other atolls. The lesions started out small, one to two millimeters, and then within a few days “tended to coalesce” into larger lesions, with a dry, leathery texture. 
As the report states: “The pigmented stage of the superficial lesions within several days was followed by dry, scaly desquamation [shedding, peeling] which proceeded from the center part of the lesion outward, leaving a pink to white thinned epithelium [tissue composed of contiguous cells that forms the epidermis or outer layer of skin]. As the desquamation proceeded outward, a characteristic appearance of a central depigmented [in this case whitened] area fringed with an irregular hyperpigmented zone was seen. Repigmentation began in the central area and spread outward over the next few weeks leaving the skin of relatively normal appearance.” 
In actual pictures of patients, areas that were touched by fallout rise up from the rest of the skin, even breaking into open sores. A few days later, the outer skin peels off, leaving white areas that heal. Eventually, the white areas repigment except if they were deeply affected, in which case they simply remain white, but otherwise are normal. Epilation (removal of hair) was caused primarily by “radiation from the fallout material on the skin…It was of a spotty nature and was confined almost entirely to the head region”. 
Pictures show hair loss and, near the bald spot, thinning and lighter colored hair. Regrowth of hair in all individuals commenced some time during the third month after exposure. “At the 6 months’ examination, complete regrowth of hair, normal in color, texture, and abundance had taken place.” 
There is remarkable similarity between the symptoms described in Leviticus 13:1–29 and those resulting from fallout:
“When a man will have in the skin of his flesh a rising or a patch (sappachath) or a bright spot, and it will become in the skin of his flesh the burn, then he will be brought to Aaron the priest or to one of his sons the priests.” (Leviticus 13:2)
Incidentally, I have translated sappachath here as “patch.” The usual translation is “scab,” but that is probably incorrect. A meaning more like the Marshallese patches (plaques) is more applicable. Leviticus 13:8 states, “If the mispachath be spread in the skin…it is a burning.” A scab would not spread, but a patch of some sort could. Some Bibles also translate the word as “rash.” Whether the Egyptian spḫꜣ (to purge or make skin sleek) is related is conjectural. The third meaning of Assyrian sapahu is “to spread” and would seem to fit the bill. Then there is the possibility of ulceration. Leviticus 13:12–13, among other places, points out that as long as the plague is white, even if the body is covered from head to foot, the patient is clean: 
“But on the day when it is seen in him raw flesh, he will be unclean, Or when the raw flesh turns, and it changes to white…And the priest will see him; and if the plague is turned to white, then the priest will pronounce clean the burning” (Leviticus 13:14–17, my emphasis). It now becomes obvious that negah tsaraath, which we’ve been translating simply as burn should actually indicate a radiation burn.
The biblical description parallels the Marshallese situation perfectly, because when their skin turned white, the islanders were well on their way back to normalcy.
As to a radiation burn on the head, note that “if its appearance is deeper than the skin, and [there] be in it yellow, thin hair, then the priest will pronounce him unclean; it is a scall; it is a radiation burn of the head or the beard” (Leviticus 13:30). The priest must quarantine him if it is not obvious that it is more than skin deep and might spread.
The comparison of the effects (and symptoms) reported in Leviticus and those in the Marshall Islands incident, I believe, strikingly shows that there is a direct correlation, demonstrating that the cloud had all the characteristics of being radioactive. It had the same effect on the Hebrews as the radioactive fallout did on the Islanders, as illustrated by this table:
Bible (Leviticus 13)
Effect on Skin
|Unclean: rising, scab, patch, bright spot—reddish-white, inflammation, flesh raw, broken open.
Clean: skin eventually changed to white.
|Lesions appeared in discolored spots, elevations in the skin, and ulcerations in highly exposed people. Skin turned to white and eventually became normal.
|Unclean: turned “yellow” and thin from plague (scall).
Clean: if plague stopped and black hair returns.
|Fallout caused hair loss. Remaining hair thinner, lighter color. After 6 months normal color hair returned.
|Garments were washed after exposure to plague.||Americans washed clothes and bathed to get rid of contamination.|
The people reporting at Biblical times couldn’t have known anything about radioactivity and radiation. They must simply have been describing what they observed, and yet they did accurately explain symptoms and treatment known only thousands of years later at the time of what was observed on the Marshall Islands and experienced in other contemporary radiation research.
The question is, then, when did the observers do the observing?
From the minimalists’ point of view, it was either never or, at best, very late in biblical history. Some say it was in the Persian Period (5th to 4th century BCE) and others in the Hellenistic Period (3rd to 2nd centuries BCE), and still further re-datings are formulated by scholars each year. It would be easy to debate whether the scientific work of archaeologists excavating sites such as Khirbet Qeiyafa (see picture below), Tell es-Safi (Gath), and the City of David, and the reading of ancient languages on artifacts thousands of years old, as with the Merneptah, Mesha, and Tel Dan stelae, or the well attested appearance of King Hezekiah of Judah in extra-biblical sources in the 8th to 7th centuries BCE, did or did not prove the existence of of biblical events and figures, but that wouldn’t take us back to the time the Bible tells us of the Exodus and the observations of the observers.
There are really only two answers as to when this all took place. The first is that the observations and events did indeed happen exactly as so completely described those many years ago in Leviticus, and the second is that the happenings regarding nuclear science could not have been known in Levitical times, so therefore the minimalists are right, the scientists and archaeologists are wrong, and the books of the Bible could only have been written at a the time when radioactivity and radiation were understood. So then, if the latter was the case, and we take the Marshall Islands comparison as our base, does that mean the Bible could only have been written (by unknown hands?) sometime in the 1950s?
If that poses a problem in the face of all the logic interred in the written biblical history, then what could the answer be?
 Note that, for simplicity, I use “clean” and “unclean” as written previously, but will go into more detail on these words below. I also simply use “plague” and “leprosy,” realizing that the Hebrew remains nega and nega tsaraath, “a burn” and “burning.”
 Cronkite, E. P., V. P. Bond, and C. L. Dunham. Some Effects of Ionizing Radiation on Human Beings: A Report on the Marshallese and Americans Accidentally Exposed to Radiation from Fallout and a Discussion of Radiation Injury in the Human Being. Washington, D.C.: United States Atomic Energy Commission, 1956, III
 Ibid., 27
 Ibid., 28
 Ibid., 33
 The terms “clean” and “unclean” are the traditional translations of Hebrew tahor and tame, respectively. Clean was a technical term for the condition wherein the danger of the cloud’s radiation was a) minimized because people and things were properly protected, or b) removed by washing, sacrifice, etc. One could also be clean simply because there was no radiation present. To be clean was to be in a state or condition free of radiation and not a radiation attractor. This state allowed for the Lord to safely dwell amid the people. Unclean was a technical term for the condition wherein the danger of the cloud’s radiation was maximized because people and things were not properly protected. A person or thing could also be unclean because radiation was present. In this state it was unsafe for the Lord to dwell amid the people. A person or thing could also actively spread material or create a condition that could attract radiation from the cloud, preventing the Lord from dwelling amid the people because of the danger. For a detailed explanation, see Isaacs, Roger David. Talking With God: The Radioactive Ark of the Testimony. 1st ed. Chicago: Sacred Closet Books, 2010, 7-11.
*With contribution from Adam R. Hemmings