About 94 tons of liquefied carbon dioxide were used to destroy 1.4 million chickens in this season. After November last year it was recognized that there was a diffused infection with highly pathogenic avian influenza across the country. According to the Ministry of Agriculture, Forestry and Fisheries (MAFF), there were 222 affected cases. Gas manufacturers and distributors were pressed with supplying carbon dioxide for culling of infected poultry.

The infection with the avian influenza has so far spread not only among chickens but also wild birds. Following the recognition of ducks for food being infected with avian flu in Aomori Prefecture on November 28 last year, chickens and ducks of poultry were infected at 10 places in 7 prefectures including Niigata, Hokkaido, Miyazaki, Kumamoto, Gifu and Saga as of the end of February, and about 1.39 million poultry birds were destroyed. In a series of slaughter disposition at this time more than 94 thousand liters (approx. 94 tons) of liquefied carbon dioxide were estimated to have been used. In the site of disposition, cylinders with siphon tubes were required to supply liquefied carbon dioxide, and the gas suppliers had a hard time to procure such cylinders. In case that MAFF has recognized a bird as suspected to be affected with avian flu, the poultry owner must destroy all the poultry to prevent any spread of the flu virus. The slaughter disposition must be carried out in compliance with the Specific Domestic Animal Infectious Disease Quarantine Guidelines.　

In the guidelines it is mandatory to carry out the slaughter disposition using carbon dioxide or bubble bird-killing machine in the livestock farming house within 24 hours after being infected. Carbon dioxide is regarded to give anesthetic effects to birds and the inhalation of carbon dioxide is often used as a means for easy death. In case of poultry one cylinder containing 40ℓ is used to destroy 500 to 1000 birds. According to JIMGA, a total of about 2360 cylinders were used concerning the damage of avian flu this time. It is an issue now how to procure the cylinders with siphon tubes to be used for the purpose. The tubes connected to the cylinder valves are dipped on the liquid surface to let the liquid carbon dioxide come out directly. The cylinder is used for the production of snow dry ice, alkali treatment, and welding, but it is not so available now with limited users while an LGC is more popularly used. Nevertheless, it is a must to secure a certain number of the cylinder for a short time as mentioned above.

In Niigata Prefecture which has experienced avian flu damages at two times, a total of 550 thousand birds were destroyed all together for which more than 800 CO2 cylinders in total were used.

According to the High Pressure Gas Welding Material Association of Niigata Prefecture, nearly 100 cylinders with siphons were procured and they were repeatedly use in a sequence of delivery-collection-filling-delivery. Looking back the past cases, the domestic outbreak of avian influenza has been checked every other year since 2005. We have had a year to dispose more than a million birds at four times including this time. Once a case has occurred, a large-scale counter-measure would be required. There must be readiness throughout the year all the time from now on.