Saturday, 21 July 2012

The Last Hurdle?

The clouds sit heavily on the shoulders of the mountains, their legs dangling down into the valleys and their toes wriggling among the trees. I have been told that Japan has the largest percentage of forested area of any industrial nation, which is a very fine thing. When the nuclear disaster occurred last year, however, the fallout contaminated wide areas of forest with radioactive materials such as Iodine 131, Cesium 134, and Cesium 137. Radioactive Iodine only has a short half life of a week or so, and has mostly dissipated by now. However, radioactive Cesium 134 has a half life of 13 years, while Cesium 137 has a half life of 30 years, and remains in the environment and becomes part of the food chain. Various government bodies have therefore introduced safe limits and testing guidelines for many food and food related products. The limit, for example, of radioactive Cesium in logs for growing Shiitake mushrooms is 100 becquerels per kilogram. In Ichikai, the amount measured was 117bq/kg, prohibiting the harvest of mushrooms in that area. The same applied for Mashiko, Haga, Mohka and a number of other places in Tochigi prefecture. Here in Minakami, there was no detectable trace of radioactive material in the Shiitake logs. HOORAY!

As I mentioned in an earlier blog, the limits imposed by the Ministry of Agriculture, Forestry and Fisheries on wood and charcoal for food preparation (including pottery, as it used for food serving and preparation) are much stricter, with a maximum limit of 40 bq/kg for firewood and 280 bq/kg for charcoal. This is because radioactive materials concentrate in the ash after burning, and the resulting ash must be safe for human consumption. For example, let's say you bake a pizza in a wood oven; if it gets ash on it, that ash goes into your mouth too, along with the radioactive materials. So, in order to ensure the safety of the pizza, you need to control the safety of the wood. In the same way, ash in a wood kiln sticks to the pots and melts into a glass, and therefore theoretically so do the radioactive materials. There is evidence that Cesium volatilises at 671C and would therefore become a gas which goes up the chimney and into the air again, which is equally horrifying. The only way to prevent this is to control the amount of radioactive material in the original fire wood. The MAFF has made it the responsibility of the wood producers and suppliers to test the wood, however, I am not taking any chances. 

As you know, I fire my kiln with recycled firewood. The wood I use comes into Japan as boxes of tobacco from the US for Japan Tobacco. It is therefore untreated with chemicals in accordance with safety regulations. In accordance with the Japanese industrial waste laws, it is then passed on to a licensed recycling company, in our case a wood supplier in Mashiko. He then bundles it into neat packages and it can be used in my kiln. I asked the wood supplier to provide certification that the wood was tested for radioactive materials and proven safe, and he in turn asked JT, who provided us with the above documentation, stating that the wood was maximum 0.15microsieverts of radiation, and well within the safe limits. SO, with confidence I fired my first test firing with my safe and wonderful wood! After the pots came out I checked them with my own handy dandy Geiger counter (never leave home without it!) and it told me that the pots were less than 0.05 microseiverts and unmeasurable with this equipment. HOORAY!!!

But wait....lets just double check everything before we sell these beautiful vessels. The MAFF says less than 40bequerels/kg for firewood. JT tells me it is 0.15microsieverts.... do you see the problem? Microsieverts is a measure of radioactivity, and Becquerels is a measure of the concentration of radiactive materials. To put it in really easy to understand terms, if faeces was a radioactive material, the stench coming off it would be radioactivity. The paperwork from JT only tells me how stinky the wood is, and MAFF needs to know how much poo is stuck to it...becquerels and microsieverts measure two different things.   

After unsatisfactory attempts to get the wood retested in becquerels by JT and the wood guy, I have discussions with the Mashiko Ceramic Institute and the Mashiko pottery Co-operative only to discover that they are unable to test for radioactive materials. ("If you have paperwork from JT that should be OK..shouldn't it?") It is very difficult to get them to understand that there is a significant difference. They tell me if I want it tested for Radioactive materials I'll have to do it myself, and point me at a testing facility in Chiba. After two days of telephone conversations I am informed that a simple test will cost me 33,600 yen, but that will not satisfy the criteria of the MAFF. A proper test will cost me 100,000 yen. At what point should I start to despair?

I contact the Gunma prefectural office of environment and forestry in Numata, our neighbouring town. I explain in detail the problem I have, and ask them what I should do? They tell me to prepare a 1 litre sample of saw dust according to the outlines on the MAFF homepage, bring it to them and they will test it for me for FREE! HOORAY!!!

On a clean sheet of plastic (free of potential contaminants) I cut ten separate bundles of wood taken at random from the wood stack with my freshly cleaned chainsaw. I gather 1 kg (which is actually more than 1 litre, but better too much than not enough!) and double bag it in two new plastic bags. I then took it straight to the Prefectural office in Numata and the very kind gentleman took my details and the sample and will contact me when the results come through. They have a back up of tests, so it will take ten days to two weeks, is that OK? YES!!!

So, if you were wondering why you can't buy my new pots yet, and why there has been this deafening silence, now you know. Probably the most important word in the mingei philosophy is "Kenzen", which means healthy or wholesome. When I make my pots, I make them for my loved ones to use. I will not compromise on safety, and until I can confidently provide art which is healthy and wholesome, we will just have to be patient. As I have said before, my vessels are a collaboration with nature, and through them I strive to enrich peoples every day lives every day. The more beautiful the process, the more beautiful the result. I will not be firing again until I have the official test results. In the meantime I will be making lots of pots in preparation for my renaissance exhibition. It has been a very long run, and hopefully this is the last hurdle.


  1. looking forward to seeing the finished pots properly!
    Hope all goes well and is good.

  2. Nothing simple about wood firing anymore! Here we mostly worry about moisture content and carbon emissions...I admire that you are not daunted by this challenge!

  3. you are a very honorable man, my fingers are crossed for a good result!

  4. I hope you jump the last hurdle with flying colours. Best wishes.

  5. So glad to hear you and your family are doing well on your incredible journey. I suppose that in the face of all of life's uncertainties, all we can do is continue on. I hope other potters in Japan are as diligent as you are in ensuring the safety of their vessels.

  6. I truly like to reading your post. Thank you so much for taking the time to share such a nice information.
    Geiger Counter

  7. Such thoroughness is not only admirable, but humbling at the same time. I feel like your due diligence will make all the difference in ensuring your confidence about the safety of your wares. Very impressive!

  8. As someone who was trained in Tochigi in the 70's and who went mushrooming with my colleagues in the hills I find what you are saying frightening and a terrible wake up call. Thank you for sharing your experience with such honesty-Burt Cohen