A recant study by Nicholas Smith, from the Tokyo office of Jardine Fleming, a stockbroking firm, found that more than 100 of the 1,500 or so incinerators in Japan failed to meet the country's (already lax) dioxin emissions criteria. Japanese law allows 80 billionths of a gram of dioxin per cubic metre of air -- 800 times greater than typical standards in Western Europe and North America. Only eight incinerators in Japan actually meet the international norm. And one, in Hyogo, continues to spew out dioxin at 10,000 times the concentration allowed elsewhere.

All that poison floating around in the air may pass unnoticed. But when it falls to earth and contaminates the soil and groundwater, it becomes harder to ignore. A wake-up call for Japanese industry -- on the scale of the Love Canal incident in America in 1980 -- came in April when the soil surrounding an incinerator in Nosecho, a residential suburb north of Osaka, was found to contain a staggering 8,500 picograms of dioxin per gram of soil. This has given Nosecho the unpleasant distinction of having the highest recorded dioxin concentration in the world.

The outcry over the toxic waste that contaminated the soil at Love Canal in New York state prodded the American Congress into establishing a trust fund (the "Superfund") -- financed by a levy on the oil and chemical industries -- to clean up such sites. In the same way, Nosecho has focused public anger on industrial polluters in Japan. Rather than being hauled over the coals, sensible firms have started to publish ugly details about the frightening condition of some of their sites.

Next a consumer-electronics giant, Matsushita, reported harmful carcinogen levels in the groundwater beneath four of its factories in the Osaka area. The level of the cancer agent tetrachlorethylene -- used for cleaning semiconductors -- at one of the plants was 9,400 times the permissible limit. At another plant, in Hokkaido, the groundwater contamination was 5,200 times the maximum. The company suspects that the groundwater beneath 80 of its 112 plants in Japan may be contaminated with harmful compounds.

Such findings have come to light more than a year after Japan's amended Water Pollution Prevention Act came into effect. But the recent rush to reveal all has been prompted as much by the "Nosecho effect" as by the retroactive nature of the legislation, which forces the original polluter to clean up affected site.

Other forces are at work, too. Japanese manufacturers have been adopting the international ISO 14,000 standard of environmental good housekeeping faster than those of any other country. By February, some 730 industrial sites in Japan had become fully compliant, compared with 525 in Britain and a mere 110 in America.

Half of the Japanese plants that have complied with the new ISO standard are in the electronics sector. Being top exporters, Japanese electronics firms have been understandably nervous about having their goods barred from countries that are signatories to the ISO 14,000

All of which is creating a handy new line of business for Japan's environmental- protection industry. Soil remediation in particular is seen as having huge potential. Kurita Water Industries, one of Japan's leading environmental- engineering firms, started building its soil remediation skills over a decade ago. It has carried out more than 400 surveys and soil purification schemes to date. As for Japan's filthy incinerators, the remedial business could be even more promising. Jardine Fleming's Mr Smith reckons that rebuilding all the faulty incinerators in Japan could cost a whopping \9.2 trillion ($66 billion).

Many suspect that the opportunities currently being exploited by the clean-up industry in Japan are merely the tip of an iceberg. Now that two of the country's most respected industrial names, Toshiba and Matsushita have voluntarily surveyed their sites for toxic problems -- and gone public with their findings -- many more Japanese companies are expected to follow suit. The pressure for them to do so is increasing as they shut old smokestack factories and redevelop the land for other uses.

But the remedial work is not just required at big manufacturers. The Environment Agency of Japan points to the plethora of small plating shops as the country's worst offender in terms of toxic waste, followed (surprisingly) by dry-cleaners, hairdressers and public bath-houses. Big industries such as chemicals and electronics follow close behind. So far, only a fraction of the small backstreet offenders have had their land surveyed. There is still a lot of nasty stuff out there in the Japanese soil. And an awful lot of work will be needed to clean it up.