Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years | Hacker News Reader

Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

npr.org

155 points_bxg1101 comments

Jeezus Cripes, way over reaction. I have Fiestaware plates that put out over 30uSv/h / 3mR/h / 9200cpm. Unrefined uranium ore puts out waaaay less that. As long as you're not sleeping with the junk under your bed or working with it next to your desk all day long you're fine. Even then, it's still less exposure than air crews that fly every day receive. No one was harmed by this.

For the reference, I measured the levels with my basic dosimeter on one flight. Measurements topped at 72 uSv/h. Common reading during the flight was in the 50-60 uSv/h range.

What I found very interesting was that the levels were slightly lower in the air near the ground than on the ground where I landed.

Maybe that just means the ground is more radioactive than air?

This is the correct answer. There're tons of microparticles of radioactive monzonite (and other radioactive minerals) in the dirt. And if you're near a granite body, you will show even higher levels of radiation.

Downvoters need to pick up a geology book.

It’s entirely plausible that in practice nobody received a dangerous amount of radiation in this case, but...

> The report indicated radiation levels at "13.9 mR/hr" where the buckets were stored, and "800 mR/hr" on contact with the ore.

> [...] The commission lists a maximum safe dosage for the public, beyond natural radiation, is no more than 2 millirems per hour, or 100 per year.

https://www.azcentral.com/story/news/local/arizona/2019/02/1...

Actually: https://www.nde-ed.org/EducationResources/CommunityCollege/R...

Regulatory Limits for Occupational Exposure

Many of the recommendations from the ICRP and other groups have been incorporated into the regulatory requirements of countries around the world. In the United States, annual radiation exposure limits are found in Title 10, part 20 of the Code of Federal Regulations, and in equivalent state regulations. For industrial radiographers who generally are not concerned with an intake of radioactive material, the Code sets the annual limit of exposure at the following:

1) the more limiting of:

A total effective dose equivalent of 5 rems (0.05 Sv)

The sum of the deep-dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 50 rems (0.5 Sv).

2) The annual limits to the lens of the eye, to the skin, and to the extremities, which are:

A lens dose equivalent of 15 rems (0.15 Sv)

A shallow-dose equivalent of 50 rems (0.50 Sv) to the skin or to any extremity.

The shallow-dose equivalent is the external dose to the skin of the whole-body or extremities from an external source of ionizing radiation. This value is the dose equivalent at a tissue depth of 0.007 cm averaged over and area of 10 cm2.

The lens dose equivalent is the dose equivalent to the lens of the eye from an external source of ionizing radiation.

This value is the dose equivalent at a tissue depth of 0.3 cm.

The deep-dose equivalent is the whole-body dose from an external source of ionizing radiation. This value is the dose equivalent at a tissue depth of 1 cm.

The total effective dose equivalent is the dose equivalent to the whole-body.

Declared Pregnant Workers and Minors

Because of the increased health risks to the rapidly developing embryo and fetus, pregnant women can receive no more than 0.5 rem during the entire gestation period. This is 10% of the dose limit that normally applies to radiation workers. Persons under the age of 18 years are also limited to 0.5rem/year.

Non-radiation Workers and the Public

The dose limit to non-radiation workers and members of the public are two percent of the annual occupational dose limit. Therefore, a non-radiation worker can receive a whole body dose of no more that 0.1 rem/year from industrial ionizing radiation. This exposure would be in addition to the 0.3 rem/year from natural background radiation and the 0.05 rem/year from man-made sources such as medical x-rays.

> A total effective dose equivalent of 5 rems (0.05 Sv)

Most places moved to 20mSv now and use 50mSv for short term (100mSv is detectable chance of cancer developing). Average US worker exposure is ~2mSv/yr.[0]

[0] https://www.world-nuclear.org/information-library/safety-and...

While there is nothing to harm you, apparently, shouldn't it be still a goal for us humans to try to use materials which do not radiat at all?

How much impact does radiation has on our cancer rates we at the moment?

I mean, i would accept the risk of flying and getting a xray but i would probably try to choose my building materials differently if it would make sense.

> shouldn't it be still a goal for us humans to try to use materials which do not radiat at all?

At this late stage, that is probably an impossible goal to meet.

Pretty lacking on specifics. What was the actual radiation level measured? I would assume these were not buckets of pure uranium, but of uranium ore that is naturally all over the place in the West, and not terribly radioactive in its natural state.

True, it was a little vague. They mentioned the measured levels after the bucket was removed, but not before.

There is one quote that leads the reader to believe that the radiation was pretty strong:

> at levels he calculated to be 1,400 times the Nuclear Regulatory Commission's safe level for children.

Note that it doesn’t mention the timeframe that the children would have to be exposed to the buckets to get that number. It mentions 30 minutes earlier, but it’s unclear whether 30 minutes was used to get the “1400 times” figure.

Yeah, I've always found vague calculations of radiation exposure like this to be highly inaccurate, mostly because people can't into inverse square law and fuck up the units. I'll wait until the OSHA investigation to reveal more accurate information; my opinion is that it's the lifelong employees who hung around the area who should actually be worried, instead of some kid who went on a field trip there six years ago.

* 800 mR/hr if you physically touched the rocks

* 280-320 mR/hr if you physically touched the bucket(s)

* 13.9 mR/hr if you were within 5 ft

* 1.85 mR/hr inside the building more than 5 feet away. Also can be thought of as "0 mR/hr above background"

* 2.02 mR/hr outside, in the park, on a bright sunny day.

2.02 is "background". i.e. the levels everyone is getting from natural sources outside.

13.9 mR/hr is 139 microsievert (µSv) per hour

So, really its that being near the buckets was 139 µSv/hr. A child would get ~70 µSv in that half hour, in theory. If we believe Randall Munroe's (of xkcd fame) sourcing in https://xkcd.com/radiation/, then that means the kid got less than a round-trip flight from NY to LA sitting there for 30 minutes. "1400 times" sounds like one heck of a scare tactic. Not saying this was smart, but its overly alarmist.

Numbers are from a picture I found. Scroll down a section on "Takeaways from the report" where it summarizes the exposure. https://www.azcentral.com/story/news/local/arizona/2019/02/1...

You do get a lot more exposure if you’re working at the museum every day though.

Only if you spent hours within 5 feet of the bucket.

(That's what the comparison with sunlight is aboot)

They are cumulative, if you walk around the museum every day you could easily rack up hours with 5 feet.

Note that the South Rim of GCNP is at 7,000 feet (2100m) elevation. Also, next week, Feb 26, GCNP is 100 years old.

Note also that GCNP contains all kinds of radiation sources. I was there with my wife a year ago doing some backcountry hiking.

We went in via Horseshoe Mesa. There are signs near the campground on Horseshoe Mesa warning you to stay out of areas where there was mining activity. We shoved on from there because our permit for the night was for further down rather than any concern about radiation.

More titillating is the warning in the backcountry hiking guide for the Tonto Trail from the Bright Angel Trail to the Hermit Trail:

"There is water in the bed of Horn Creek about half the time, but unfortunately it is radioactive so don't drink it unless death by thirst is the only other option. The source of the radioactivity is a deposit of high quality uranium contained within a collapsed cave system geologists call a breccia pipe." [0]

[0] https://www.nps.gov/grca/planyourvisit/campsite-information....

The milliroentgen values are probably wrong - 800 mR/hr would be way too much, something I wouldn't recommend touching :-). The average background radiation is around 0.010 mR/hr - or 0.1µSv/hr.

From a screenshot at [1]

* 800 mR/hr if you touched the ore

* 280 mR/hr on the surface of the bucket (sealed)

* "0 above background" if you were 5 ft away from the bucket

* 2.5 mR/hr if you were touching the cabinet it was in

[1] - https://www.azcentral.com/story/news/local/arizona/2019/02/1...

Basically unless you were having a very prolonged and loving relationship with the bucket, you were exposed to nothing of consequence. That doesn’t excuse the morons who kept this stuff, and if a kid took a souvenir home or there had been a fire it could have been a lot worse. They may have also had unacceptable levels of radon. If I worked there I’d want to know more, but just as a visitor I’d shrug and get on with life.

I’m wondering why they used R instead of Sv though. It’s a single source with a single quality factor, and were only concerned with the impact on humans.

Roentgens are historical units of exposure, it's simply what a lot of older meters read.

Roentgens can be assumed to safely equal RADs (although they don't, conversion is less than 1 for kV), the historical unit for "Radiation Absorbed Dose." For photons this would be equal to REM "Radiation Equivalent Man."

All old units; conversion to S.I., 100 rad = 1 Gray (J/Kg), 100 rem = 1 Sievert.

Essentially, who ever wrote the report was old and conservative.

The occupational risk is also essentially nil. This is much ado about nada.

assuming inhalation if dust was not an issue..

5gal buckets are designed to be handled by all manner of people who don't have enough time to give a crap and still get to their destination without leaking.

A properly sealed 5gal bucket will remain air tight even if it's bouncing around inside a tote in the bed of a truck on rural gravel roads for ~10mo (the tote flooded at some point but the bucket wound up dry).

Sitting in a cabinet the risk of dust making it out of the bucket would have been nonexistent so long as the lid was on it.

I assumed it was open so people can look at the ore

Time to whip out the XKCD radiation chart[1], which gives us measures around:

* One chest CT per hour for touching the ore (or about 9 hours touching the ore to reach your annual max dosge)

* One head CT per hour for touching the bucket

* nothing for 5ft away

* One chest XRay per hour touching the cabinet (less than a cross-country flight LA <-> NYC)

[1] https://xkcd.com/radiation/

I've seen this chart and yet it's always fascinating.

A dental X-ray is like eating 50 bananas, and half of what you would get over the course of a normal day.

50 bananas is an interesting quantity in that it is conceivable you could eat that many in short order, but I'd be worried about someone who did (but not because of the radiation).

The record for bananas eaten in 1 sitting is 30:

https://recordsetter.com/world-record/bananas-eaten-sitting/...

And the record most in 1 minute is “only” 8.

That sounds like a challenge for Matt Stonie

The CT scan is the interesting one. I've talked to some researchers about CT scans, and how they do increase cancer risks. It's not very much, but for serious long-term conditions you might get several CT scans per year and that could increase your cancer risk. When looking up studies the numbers are pretty low, usually under 10%, but it is an interesting risk to be weight against diagnosing and treating the underlying condition.

The physcists we have had come in to check x-ray gear can generally do a conversion to banana equivalent dose in their head when asked. Seem to check out as accurate too.

assuming the X-ray equipment is not faulty. I need to mention any specific famous cases of that not being true...

>Stephenson said the containers were stored next to a taxidermy exhibit, where children on tours sometimes stopped for presentations, sitting next to uranium for 30 minutes or more. By his calculation, those children could have received radiation dosages in excess of federal safety standards within three seconds, and adults could have suffered dangerous exposure in less than a half-minute.

>The Nuclear Regulatory Commission measures radiation contamination in millisieverts per hour or per year. According to Stephenson, close exposures to the uranium buckets could have exposed adults to 400 times the health limit — and children to 4,000 times what is considered safe.

https://www.usatoday.com/story/travel/news/2019/02/18/grand-...

If they had just let them sit there for 4 and a half billion years they would be half gone :-).

If you hike around the Grand Canyon you are going to be exposed to Uranium. There are a lot of mines in and around the place (see here: https://www.grandcanyontrust.org/grand-canyon-uranium). It really isn't something to worry about unless you want to live their and/or eat food that has been contaminated.

The f*ed up part is the impact on the fetus. The dosage level before harm or death for kids is 10x smaller than for adults. For babies in the womb it is way smaller than that.

These folks may have covered up something that resulted in the miscarriage, or birth defects of the child of any pregnant woman who stood near that closet for just a few minutes.

I think the folks who covered it up for 8 months, or the morons who (threw the rocks in a hole and brought the nuclear-contaminated buckets back) should lose all their power and position. That is an amazingly bad decision.

Lucky thing some kid walked around with a geiger counter. He recorded the levels, so the numbers that officials are hiding, he knows them. His counter can be tested and certified by a decent national lab, and the exact and calibrated level of the radiation determined. And those contaminated buckets tell something about the material that was in them.

Ore shmore. It is a radioactive substance that gives off dangerous levels of alpha, beta, and gamma radiation, as well as nuclear byproducts like radon and other gaseous nuclear isotopes.

Get more than the "top paragraph summary" that NPR did on the original AZ Central article by reading it in its entirety.

https://www.azcentral.com/story/news/local/arizona/2019/02/2...

> Lucky thing some kid walked around with a geiger counter. He recorded the levels, so the numbers that officials are hiding, he knows them. His counter can be tested

Neither the linked article nor your's said anything about what kind of "geiger counter" this kid had; whether it was something picked up off ebay, an old civil defence unit, or some kit or custom made thing from Electronic Goldmine (a native AZ electronics surplus and education kit supplier - https://www.goldmine-elec-products.com/)...

It's very well possible that the kid has no real numbers; that is completely unknown.

I'd be willing to bet you could walk into an old mining bar in Flagstaff and have more exposure to natural radiation used in the building materials than you'd experience from these buckets of old ore. Natural radiation sources like these are all over the place in Arizona.

The only real danger I could see and understand, though, is whether these buckets were covered or open; could someone or a kid have "dug through them" with their hands, or been in closer proximity to the material inside - where the dust or whatnot could be left on their hands to be ingested or inhaled in some manner.

That would be a much different situation than merely being near it for a small amount of time.

> where the dust or whatnot could be left on their hands to be ingested or inhaled in some manner.

This by far would be my number one concern. Proximity doesn't seem to be much to worry about (238-Uranium has an alpha decay and doesn't travel far in air). But inhaling or ingesting radioactive material completely changes the danger level.

> Natural radiation sources like these are all over the place in Arizona.

Or... Grand Central Station. But... you have to consider context, which a lot of reporters don't. Consider this quote.

"It's worth noting that if Grand Central Station were a nuclear power plant, it would be shut down for exceeding the maximum allowable annual dose of radiation for employees."[0]

Yikes! We can trace down the dosage level to 120mrem/yr[1] (1.2mSv), which we can indeed see is on the order of average dosages for radiation workers [2] or 1/20th of the allowable dosage! BUT we can look at [2] more and see that 100mSv is "Lowest annual level at which increase in cancer risk is evident (UNSCEAR)" (threshold model).

So when I see articles like this I'm always a tad hesitant to even read them. They frequently focus on the first part of the last paragraph and give no indication to what these things mean. Or even worse, are misleading like that gizmodo article (I would in fact call this dangerous reporting). Radiation quotas are purposefully (and I agree with this) put to be far below what one might also call "safe" (I'd _upper bound_ "safe" as <100mSv/yr but think most would agree 20mSv is "safe"). Yeah, we should pay attention and not expose ourselves to radiation unnecessarily, but let's also be realistic about the danger (especially when we're in such dire need if we're going to solve our climate problem).

[0] https://io9.gizmodo.com/grand-central-station-is-radioactive...

[1] https://www.pbs.org/wgbh/pages/frontline/shows/reaction/inte...

[2] https://www.world-nuclear.org/information-library/safety-and...

[3] https://jciv.iidj.net/map/ (just for fun, now that we have some understanding of what these numbers mean).

Hysteria like this is why it's almost impossible to have rational conversations about things like radiation or nuclear power.

> ...something that resulted in the miscarriage, or birth defects of the child of any pregnant woman who stood near that closet for just a few minutes.

If we really are talking about a couple of buckets of uranium ore, then no, standing near them for a few minutes will not cause miscarriages or birth defects. Even the AZ Central article, in the midst of its fear mongering, says, "Just 5 feet from the buckets, there was a zero reading." The rest of the article is no more helpful, giving not nearly enough context to the cited measurement for readers to draw any conclusions.

> It is a radioactive substance that gives off dangerous levels of alpha, beta, and gamma radiation, as well as nuclear byproducts like radon and other gaseous nuclear isotopes.

Radon yes, and as I learned from another HN thread regarding this same story, radon can be generated at much higher rates than I ever realized. However this is highly unlikely to affect anyone who didn't spend extended periods of time in an enclosed (or sub-grade) space with the ore.

Gamma radiation here wouldn't be significant. Alpha radiation is stopped by mere inches of air. As with alpha, beta radiation is only hazardous if the material is inhaled or ingested. And aside from radon, there are no gaseous elements in uranium's decay chain.

I suppose, if the rocks were chalky and they were taken out the bucket and played with frequently, there could be some kind of inhalation risk. On the other hand, mineral dust is heavy, and typically settles out of the air too quickly to be a significant inhalation hazard. We see something similar with lead, where leaded dust from paint and vinyl mini-blinds is mainly a hazard to babies and little kids who can get their faces right in it, or eat things off floors and window sills.

Otherwise, it's hard for me to imagine how this material could have posed a health hazard to visitors.

Years ago, I was working in a biochem lab, and helping a state senator's staff draft legislation. The state capitol building was classic granite and marble. So one day, I brought in a Geiger counter. Everyone freaked ;)

did you test your kitchen counter?

Well, at that point, my kitchen counter was Formica over plywood, so not much of a radiation source. But I did test my wife's Mexican pottery, and some pretty enamelwork and art glass. Freaked her too ;)

But yes, much granite does contain substantial K-40 (as do we) and some (probably less than 10%) is a substantial source of radon. Also thoron, but it's too short-lived to accumulate. You can buy test kits designed to measure radon production rate from surfaces. The radon gets captured on activated charcoal. You return the kit(s) to the provider, and they send you results.

Discussed yesterday:

https://news.ycombinator.com/item?id=19195087

Not nearly as interesting as the radioactive boyscout story:

https://harpers.org/archive/1998/11/the-radioactive-boy-scou...

David Hahn sadly passed away at 39:

https://arstechnica.com/science/2016/11/this-fall-the-radioa...

It would be amazing and not unlike his character to have staged his death.

The boysout and the smoke detector nuclear experiment is one of those really amazing and interesting stories.

Geeze, I wanted to look up him, thinking he'd have gotten an engineering scholarship or something. Looks like he served in the military, but afterwards he got addicted to drugs and died in his late 30s. ... .. Geeze that's fucking tragic.

Which takes me back to a shower thought I had a long time ago: How do you know you don't need a geiger counter unless you have one?

Somebody else has one?

Realistically though most things aren’t radioactive in a meaningful way.

Yep! I carry a Gamma Scout in my car: https://www.gamma-scout.com/EN/GammaFAQ.php

I had the same thought, and wanted to check some strange ore from the desert. Eventually I soldered my own Geiger counter, thanks to the fabulous Safecast project. This is it: https://blog.safecast.org/bgeigie-nano/

It cost ~$650, but that's because it uses a very high-end geiger tube, and can detect alpha and beta in addition to gamma radiation. Comparable commercial devices do apparently cost a couple thousand.

Low and behold, the desert rocks weren't radioactive. However, taking the counter on an airplane was quite shocking, and gave the cabin crew real concern.

> ...taking the counter on an airplane was quite shocking, and gave the cabin crew real concern.

Concern about radiation exposure or concern about the mysterious-looking device you whipped out mid flight? ;)

I hadn't heard of Safecast before. Very interesting! Nice data sets there, too.

They've issued a correction clarifying that it is Uranium ore, not straight Uranium.

This paragraph didn't make sense to me: "Photos provided to the newspaper by Stephenson show technicians arriving in June 2018 to take away the buckets of uranium ore. The technicians reportedly dumped the buckets at an old uranium mine 2 miles away, then for some reason brought the buckets back to the building."

I'm guessing they mean "dumped" the contents of "the buckets"

https://n.pr/2XfmoZh NPR correction

My mother still has old uranium glassware in her home. Not really sure if it's dangerous or not but it's pretty cool to see in person.

Radiologically, Uranium glass is virtually harmless. However I believe Uranium glass often contains a lot of lead as well, similar to the lead crystal glassware a lot of people own. Lead crystal glass is mostly harmless but not totally harmless, if you leave anything alcoholic or acidic in it long enough, it will leach a significant amount of lead. Used briefly on occasion it's not really a big deal.

It’s important to down the drink fast to reduce the risk of poisoning?

It's not quite that serious. It's fine to serve yourself with a lead crystal but you shouldn't be storing wine in a lead crystal decanter or something like that.

https://en.wikipedia.org/wiki/Lead_glass#Safety

Uranium ore is mostly alpha particle radiation. Clothing and aluminum foil are generally sufficient to block alpha particle radiation. Uranium metal can be up 28% beta particle, which can be blocked by sandbags or a thick brick wall. Depleted uranium contains almost no beta particle radiation. Uranium ore lacks the purity of uranium metal and usually more beta particles than depleted unranium but not much more though it’s purity and composition are naturally variant.

Because of that uranium is radioactive and that radioactivity is harmful, but is not the primary harm, unless you are allergic to uranium at which point the radiation is the primary harm. Also, sensitivity to radiation varies wildly by person. Uranium is a high density metal that has some dissolution capability into water, like lead, which means heavy metal poisoning. Uranium is more dense than lead and thus more poisonous but less poisonous than osmium. Under certain conditions uranium can be (or become) very brittle and break apart into a fine dust that can be respirated.

> Uranium is more dense than lead and thus more poisonous

I think there’s a little more to heavy metal toxicity than that...

How so?

https://en.m.wikipedia.org/wiki/Metal_toxicity It appears as there if is little correlation between metal density and toxicity

Weird, your source says the opposite.

> Toxic metals sometimes imitate the action of an essential element in the body, interfering with the metabolic process resulting in illness. Many metals, particularly heavy metals are toxic

Metal toxicity is the correlation between density and reactivity.

Iron and manganese are limited exceptions where iron is about 84% of hemoglobin, which is about 80% of red blood cells, but its toxic (though in larger doses) matches almost exactly the implications of other metal toxicity.

> Weird, your source says the opposite.

No, it doesn't. Your quote truncates a sentence that supports GP's point.

The remainder of that sentence does not suggest anything about density. But, I will ask your expert opinion: What makes metals toxic and what makes heavy metals more or less toxic than other metals?

"Toxicity is a function of solubility."

First sentence of third paragraph in linked wiki page.

I mentioned that specifically in my original comment.

No, you said that uranium (which you say is toxic because of its density) "has some dissolution capability."

It pleases me you can read. For a second I was about to lose faith in humanity.

Gold is nearly twice as dense as Lead, but it's completely safe.

Metallic gold is pretty inert. Ionic gold, on the other hand, is toxic.

Gold is toxic if consumed regularly. The symptoms of gold poisoning are no different than other forms of metal poisoning. The primary difference between gold and uranium is that gold isn't very reactive and so it has virtually no contact toxicity. Also, some people are allergic to gold, which does manifest contact toxicity.

Metallic gold is completely safe to consume. You'd have to be taking deliberately prepared compounds to suffer from toxicity.

* https://en.wikipedia.org/wiki/Gold#Toxicity

> Although the gold ion is toxic, the acceptance of metallic gold as a food additive is due to its relative chemical inertness, and resistance to being corroded or transformed into soluble salts (gold compounds) by any known chemical process which would be encountered in the human body.

This is true of known natural metabolic processes, but not true with connection to certain drug interactions. Gold is not chemically inert and can be converted into an ion or gold salt, even within the body, when mixed with other reactive non-toxic chemicals. Gold metal is popularly consumed in trace amounts of certain alcoholic beverages and there are many medications that should not be taken in connection with alcohol for many different metabolic altering processes. I am not sure if it has been thoroughly tested, but a combination of gold and nangarin could also result in potentially toxic consequences, which is why certain fruits are forbidden with consumption of certain other chemicals/drugs.

This is exceedingly rare though, since platinum group metals are so expensive, but the same conditions are observed with other platinum group metals. Silver is more toxic than gold because it is more reactive, but the behaviors are similar. A major symptom of advanced toxicity from platinum group metals is a changing of skin color towards the metallic color of the metal toxin.

For the purposes of human consumption, metallic gold is inert. I've probably eaten on the order of a gram in the last decade. It ends up in the toilet.

* https://www.nuclear-power.net/gold-affinity-electronegativit...

Gold has a far lower ionization energy than you are giving it credit for, which means it is capable of becoming toxic with relatively minor interactions. The safe for consumption statement implies interactions natural to human physiology are not likely to make gold toxic, but that doesn't account for other things humans consume that do trigger reactions not normal to human physiology.

Like gold we generally believe fruit juice is safe for consumption. Fruit juice is even classified as safe for consumption, like gold, by the FDA. This was proven to be not completely true when the price of grapefruit production fell in the 1980s. Certain chemical interactions with fruit juice will make you sick and in extreme cases will kill you. This phenomenon was only discovered because of numerous associated deaths.

* https://en.wikipedia.org/wiki/Grapefruit%E2%80%93drug_intera...

I remember visiting the Toronto science centre in the 1970s and just pickingup a block of uranium for comparison with a block of aluminium and perhaps other ones. They wanted to teach kids about density.

Glad they didn't use plutonium, which is toxic!

Uranium is toxic too, but I bet that was depleted uranium, which isn't all that radioactive and the bigger danger is its regular toxicity:

https://en.wikipedia.org/wiki/Depleted_uranium

Can any of the down voters add a comment? Is this inaccurate?

I didn't downvote, but I was surprised to read in that link that "DU used in US munitions has 60% of the radioactivity of natural uranium". I knew already that the US fired a lot of it at Iraqis not long ago and it's still killing them. That wiki page links to this 2013 story:

"Official Iraqi government statistics show that, prior to the outbreak of the First Gulf War in 1991, the rate of cancer cases in Iraq was 40 out of 100,000 people. By 1995, it had increased to 800 out of 100,000 people, and, by 2005, it had doubled to at least 1,600 out of 100,000 people. ..."My colleagues and I have all noticed an increase in Fallujah of congenital malformations, sterility, and infertility," he said. ... the Fallujah health crisis represented "the highest rate of genetic damage in any population ever studied". ... Doctors in Fallujah are continuing to witness the aforementioned steep rise in severe congenital birth defects, including children being born with two heads, children born with only one eye, multiple tumours, disfiguring facial and body deformities, and complex nervous system problems. Today in Fallujah,...many families are too scared to have children..."

https://www.aljazeera.com/indepth/features/2013/03/201331517...

We were nowhere near the Grand Canyon.

As correctly pointed out by other readers, this is a non-issue and complete overreaction. All feeding into misconceptions and irrational fear of radiation.

The "safety professional" was out of his depth and clearly undereducated about the risks of radiation and uranium ore in particular.

Hence, the true risk of a "dirty bomb" -- is psychological, i.e. it would be a weapon of mass disruption (not destruction), triaging a "worried well" would be expensive and time consuming.

> Hence, the true risk of a "dirty bomb" -- is psychological

I imagine there are some radiation-sources which are harmless outside the body because the dead cells of your skin would easily absorb and block them, but would wreak havoc if they were ingested or inhaled as dust.

Sometimes this is presented as a question where you have three or four cookies, which emit things like alpha/beta/gamma radiation and possibly neutrons, and you have to decide which cookie to eat, which to put into your pocket, which to put in a lead box, etc.

Given everything people say about the 2008 crash, destroying the housing market in a few key places seems like it would have a bigger effect than outright killing a few hundred people, unless it's a made-for-television spectacle like the WTC. Dirty bombs are totally a weapon against real estate prices lol

On a purely radiation focused scale, sure. But this is a big deal, as it’s an indicator of the lack of effective management and controls surrounding it.

Where did it come from?

Why was it stored where it was stored?

Why did employees just dump the material?

They're rocks that someone undoubtedly collected from the surrounding area. Radioactive rocks, emitting low levels of mostly self-shielded radiation. Not great, but not a disaster deserving of national news.

I got the impression that they might be some old dirt ore from the 1950s - back then, there were a ton of articles in magazines like Popular Science and Popular Mechanics (check 'em out on Google Books and the like) about the "new gold rush - for uranium ore".

Lots of people from all over drove out to the southwest with bucket and shovels, and tried to find this stuff in a (probably misguided) attempt to "strike it rich".

I'm sure more than a few just left their buckets of dirt sitting around Flagstaff and GCNP area - and they were found and moved around - and...

...here we are.

May or may not be true in this case - but I'm sure it has happened (and I am certain more buckets wait to be found).

Depending on the radiation level the public may have benefited via radiation hormesis. With only the given data it's hard to know if this was a net health menace or boon.

The radiation hormesis theory[1] isn't widely accepted and shouldn't be used as a policy mechanism until there is much more known about its legitimacy and limitations.

[1] https://en.wikipedia.org/wiki/Radiation_hormesis

Also, if one abandons the idea that dose response is linear, there is the possibility that the slope is even larger in the low dose regime than LNT would predict. The conservative approach would then be to adopt stricter limits, not looser ones.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6043938/

Nothing there contradicts what I wrote.

The notion seems to be the alternative to LNT is "radiation is not as bad at low doses as LNT". But there are many alternatives, all consistent with the evidence, and some would have the effect at low doses be worse.

Radiation is not a criminal defendant that requires proof beyond reasonable doubt to be regulated.

Expensively regulating something well below any detectable effect could have negative consequences regardless of whether or not it is a criminal defendant. For instance, nuclear power plants are very nearly carbon free, yet they're expensive in part because of the Linear No-Threshold model of radiation dose at very low doses. If they were cheaper and we were fully decarbonized in 1995, we could avoid the other more detectable effects of global warming.

Airline workers are exposed to more radiation than "radiation workers."

No regulations, and no alarmist theories of risk.

-- Not saying it shouldn't be regulated, just that the regulations are inordinately strict and out of line with the evidence.

It's weird you think you're making an argument there.

The problem is that radiation effects at low doses are very difficulty to detect. They could be very bad per unit of radiation and we could not now rule that out.

You're assuming that an unknown risk is _worth_ spending money on to regulate. Don't know if there are boogey men, better protect against them. Costs be damned.

Your mindset is that the risk has to proven, as in a court of law, before it can be regulated.

This is Lawyer Science, not actual science.

Science is not the regulation of the unknown. So, I dont understand your position at all.

And not court of law, by evidence and observation, i.e. science.

LNT is lawyer science, low dose radiation risk (cancer induction) is stochastic. There is already a high prevalence of cancer in society. To protect against possible litigation we eliminate sources as a possible induction points.

However, iff you developed a radiation induced cancer there's very little way to determine if your (mulitple) DNA errors were induced by cosmic rays or that time you walked past a bucket of naturally occurring radiation or due to those flights you took from Colorado to Brazil.

The dose makes the poison, we protect (and waste inordinate amounts of time and money) against low levels -- because we're ignorant to the precise pathways of cancer induction.

Science informs regulation, but regulation is the product of politics.

I'm also surprised that others were quick to shoot the hormesis messenger. This is very well established mechanism of action.

Priming DNA repair pathways acts as a protection from further exposures.

However, and this is my take -- there are people in the population that are more sensitive to the sun. These same people are probably more sensitive to ionizing radiation, LNT protects all, including the most sensitive. That being said, it's taken to an extreme, and allows for sensationalism and fear mongering.

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