"For the sake of good environmental policy, it is necessary to have freedom of expression which forms public opinion." These are the words of Sweden's environment minister, part of a press release issued in March 1999, following the arrest of several Greenpeace activists who were in Tokyo protesting PCBs in children's toys.

Greenpeace protesters display a banner at the Ikebukuro Incinerator and "Health Plaza."

The minister's sentiment is by no means revolutionary. Throughout the developed world it is understood that freedom of expression nourishes democracy. Individual and community health are threatened whenever the marketplace of ideas is starved of information.

In Japan, however, this self-evident truth remains nascent. Japanese authorities run a selective democracy that accommodates useful opinions, while muffling those that run counter to the status quo. Rightwing sound trucks regularly cruise the streets blasting martial music and marginal propaganda, disturbing the peace with impunity. Just last week, a major political party parked a truck outside my home and harangued local residents for 30 minutes at decibel levels that shook the house.

In contrast, twice in the past two years professional climbers working with Greenpeace have scaled buildings in Tokyo and unfurled banners protesting dangerous and widespread health threats: first PCBs, then dioxin. Despite peaceful methods, timely and essential messages, and no harm to persons or property, the climbers in both cases were arrested and held for 11 days.

In the most recent protest, four Greenpeace activists were arrested May 9 after scaling a waste disposal complex in Ikebukuro, Tokyo, that boasts the world's tallest incinerator. For three hours before descending, the protesters displayed a banner reading "Burn first, safety second, Tokyo -- dioxin capital."

According to a May 1999 U.N. Environment Program report on dioxins and furans, Japan is responsible for at least 40 percent of the annual emissions of dioxins generated worldwide.

The activists were immediately arrested and jailed under Japan's daiyo-kangoku system (detention in police cells), which allows suspects to be held up to 23 days in police custody without an indictment. On their 11th day the climbers were charged with trespassing, told to pay a fine of 70,000 yen and released by the Tokyo District Court.

Granted, they were trespassing, which is illegal. However, considering the content of their message, and the peacefulness of their protest, the form and duration of their detention was unusually severe. In similar protests worldwide, Greenpeace activists have never been held so long. Of course, this is Japan, but that's my point. Why is Japan so selectively intolerant of just environmentalists' free speech?

Whatever the reasons for their treatment, the climbers were all amazed by the conditions of their confinement and the numerous hours and days the police and prosecutors dedicated to their case.

The day after their release from prison, I talked with two of the climbers before they left Japan: Marleen van Poeck, from Belgium, and Alan Baker, of the U.K.

Van Poeck joined Greenpeace in 1995, and is a trained cave climber and explorer. Baker has been with Greenpeace for 10 years and has spent years training other Greenpeace climbers. He is a rock-climbing instructor trained in mountain rescue. As Baker said, "We knew what we were doing."

Japanese were not included in the climbing team because they lacked skill, and because of the stigma attached to being arrested in Japan. All participants in Greenpeace actions must be willing to face arrest, Baker explained, adding that several Japanese were eager to take part. Even a moderately skilled climber could have made the ascent, since there are ladders up both sides of the building.

The building was chosen because it could be climbed without damaging the structure, and pictures could be taken of the banner with the incinerator in the background. The climbers were on the building for three hours with a banner measuring 10 by 8 meters. The whole event involved four climbers, according to van Poeck, and 120 police officers.

Baker and van Poeck were genuinely surprised to be arrested. "Generally in Europe," Baker noted, "they just want to write your name down and get rid of you." Other countries, Baker said, "are trying to avoid the kind of global media attention that Tokyo attracted with these arrests."

"The problem remains and has to be protested," said van Poeck. "The intention isn't to get arrested."

Still, Baker admitted, "One of the best things for us was the arrest and all the uproar. It put this issue out globally."

What right do foreigners have to protest Japan's domestic problem?

"It's everyone's problem," Baker replied. "There are thousands of incinerators in Japan producing dioxin, and they are not just polluting Ikebukuro, they are polluting the planet. Anything you buy here has got three times more packaging than it needs. Japan could cut its incineration by two-thirds if it cut down on packaging and had more recycling."

As soon as the activists were arrested, they were taken to separate stations. Baker was jailed with a Nigerian and two Japanese. Van Poeck was taken to Tachikawa Police Station and put in a cell with a Korean, two Japanese, a Colombian and a Polish woman.

"The biggest impression it left me with after seeing other foreigners in jail," said van Poeck, "is that it makes a hell of a lot of difference if you've got a strong country or organization behind you." Her Polish cellmate had been in jail for months with minimal embassy contact. The Nigerian with Baker had never been visited.

"We weren't treated badly by any of the detectives or prison staff," Baker assured me, "no different from anybody else. It's just that the system is archaic and brutal -- being lead around with 20 other guys handcuffed together on a rope, forced to sit together without talking for nine hours."

It became clear early in the ordeal that "the police were very keen to target the Japanese Greenpeace office," said van Poeck. "On the day after the arrest I admitted to all the facts," she said. "From then on I was questioned every single day on matters only related to the Japanese office."

Baker was interrogated for three days. "The amount of time and money wasted on arresting us was phenomenal," Baker said.

Sanae Shida, executive director of Greenpeace Japan, is particularly concerned that the Japanese media have scarcely taken up this issue, one that involves deadly toxins, suppression of freedom of expression and the human-rights abuses of the police-station detention system. "Most of the media don't seem to care," she said. "They accept the system simply because it's 'the system.' "

Perhaps the next Greenpeace banner should read, "The system's killing you, but speak out at your peril."

Next column, the latest dioxin findings, here and abroad.