During the first phase of high economic growth in the 1950s, the greatest environmental pollution problem was caused by dust and other airborne particulate matter. The main source ofenergy at that time was coal. Dust-collectors and other methods of particulate-matter controlwere either not provided or not working, and all of the chimneys belched forth black smoke.This situation continued into the next decade, so that by 1961 a major iron and steel complex inYahata, northern Kyushu, was pouring 27 tons of particulate matter per day into the city's air,and in Kawasaki City, situated in the Tokyo Bay industrial area, the amount was 23 tons. Alongwith the black smoke there was also a great amount of red smoke that spread over the sky. Afterthe close of the Second World War, production technologies changed and the oxygen blastfurnace was introduced. This made it possible to produce a better quality steel, but the reactionby-products included a great deal of particulate iron oxide, which was scattered far and wide.Soon after that the LD oxygen blast furnace was invented in Austria, and this produced evenbetter quality steel by blowing oxygen into the furnace. However, this method also caused therelease of a large amount of red smoke and iron oxide particulates, but Japanese industrialapplications of the furnace did not include the use of dust-collectors. Because of this the amountof pollution from red smoke particulate matter greatly increased.Many industrial workers were exposed to the industrial dusts in the atmosphere, and as a resultdeveloped various lung disorders. These problems were found most widely among mine workersand those who were involved in tunnel construction. In 1955, the government was forced todevise special protective measures in order to protect the miners from such occupationalhazards. In the same year the Tokyo Metropolitan Government issued orders that made itmandatory to control heavy smoke and dust production. This...