Radioactive junk at my house

We've been going through a relative's stuff, and helping her to downsize now that she's getting up there in age.  As part of the process of sorting through those possessions, my wife was given a box of ceramic dishes.  She thought that they were pretty and wanted to display them.

I saw my wife unpacking her treasure, and she mentioned that it was "Fiestaware or something similar".  That caught my attention right away.  It doesn't have the Fiesta stamp on the bottom, but it does share a very interesting characteristic with Fiestaware.

It's not a well-known fact, but many of these old dishes used a glaze that contains Uranium Oxide (UO2).  It was very common from the late 1930's through the early 1970's to use glazes containing Uranium Oxide to get the desired reddish-orange color.

Below, a Fiestaware plate coated with "radioactive red" glaze.

There was a brief hiatus making the red glaze during WWII due to the US government impounding all available Uranium ore, to provide raw material for the Manhattan Project - the atomic bomb.  After WWII, production of glazes resumed, using depleted Uranium.  Depleted Uranium is what remains after the fissile U-235 has been stripped out, leaving behind the non-fissile (but still radioactive!) U-238.

Other colors of ceramic glaze are known to be radioactive, including yellow and ivory colors.  Red has the most activity however, due to its higher Uranium content.

Fiesta is perhaps the best known of the radioactive dishes, but any dish manufactured within this time frame that is red or orange in color is almost certain to contain a significant amount of Uranium, and to potentially be hazardous to your health.


Back at home, I pulled out my trusty radiation detector, and took some readings.

Below:  Background radiation levels in my office.

With the detector resting on a platter, it gave a reading of nearly 2700 counts per minute!  The detector started clicking faster when I approached within about 5 ft of the dish.  In the below photo, the meter is in alarm and making noise, with the red light on the left illuminated.

 I switched to a different range.  This converts counts per minute into microSieverts per hour.  Sieverts are a unit of "biological equivalent dose" (tissue damage) in modern international units.  Outside the US, and within the US scientific community, Sieverts are commonly used.

Below:  Same plate, but with the scale changed to milliRem per hour.  This is an older unit of measurement for "biological equivalent dose" (tissue damage again).  These are the units that I am familiar with.  I'm both an American and an old-timer though.  Not many people use the milliRem unit these days. 

Slightly less activity on the orange pitcher, but it's still a lot!

 

Just for fun, let's see if we can determine if this stuff is:

1.  Super-Dangerous 
2. Completely harmless 
3. Somewhere in-between

For this, we need a rule-of-thumb about radiation and cancer and then we need to do a little second-grade math.

The rule of thumb is this:
1 Rem increases your likelihood of developing cancer by 0.05%.

Now let's do some basic math:

If you spent one year with this plate strapped to your body (unlikely), you would receive a dose of 1.743 milliRem/hr x 8760 hours in a year = 15,269 milliRem or 15.269 Rem.   That's pretty significant.  

Trained radiation workers are only allowed to receive 5 Rem/year, and it's rare that they get close to that amount.  The plate would give you 3 times the legal limit if you were in close proximity for an entire year.

Below:  Nuclear workers refueling a reactor.  The plate would give you 3x their allowable exposure. 

Continuing, with our rule of thumb:

15.269 Rem x 0.05% risk of cancer per Rem = 0.76% increased risk of developing cancer every year that keep the plate next to you.  This is due to the penetrating ionizing radiation that it continuously gives off - gamma rays and beta particles.

 Below is a table showing the average medical radiation dose needed for imaging, just to get an idea how many milliRem are routinely given to patients.

Medical Procedure Doses
Procedure	Dose (mRem)
X-Rays-single exposure
Pelvis	70
Abdomen	60
Chest	10
Dental	1.5
Hand/Foot	0.5
Mammogram (2 views)	72
Nuclear Medicine	400
CT
Full body	1,000
Chest	700
Head	200

The most exposure any of these medical imaging processes give you is a full-body CAT scan, which will give you 1000 milliRem, or 1 Rem.  The plate will give you 15 times that.  Unfortunately, Fiestaware will give you that tissue damage without providing any image.

There's more bad news about Fiestaware though.  If you eat acidic foods (tomato-based and citrus foods are acidic) off these dishes, and the acid may leach the Uranium out of the glaze, and you can be internally contaminated, which is a much bigger deal.  Uranium 238 emits alpha particles.  These are highly charged, massive particles.  Alpha particles have a very short flight range, and are normally stopped by the dead layer of your skin - if you happen to touch an alpha emitter.  But if you eat it, the alpha emitter is in direct contact with your stomach and intestines, and that's where an alpha emitter can do enormous damage to your DNA and cause cancer to develop.  So don't eat off these things! 

I think we might put the Fiestaware on display up above the kitchen cabinets, but I don't want to be any closer to it than that.  Right now it's out in the garage :)

I'm really pleased that I was able to get some use from the Geiger counter - and to see it actually prove something was radioactive.  The detector comes with some nice accessories:  CD to install software on your PC.  The software allows you to share your detector data onto an internet map.  You get three charging devices and a USB cable, and a little bag to store the detector in.  All for just 80 bucks.

The best part is it will tell you if your ceramic dishes are going to make you sick!