Munich

A 12-year-long investigation into a possible nuclear link to childhood leukaemia in northern Germany took a bizarre turn last week. On 8 November, six members of an eight-strong expert commission resigned, accusing the local authorities of covering up a fire at an alleged secret nuclear lab.

The startling accusation got prime-time media attention throughout Germany. State officials immediately rejected it as a “weird conspiracy theory”, and announced that they would bring legal charges against Otmar Wassermann, a retired toxicologist at the University of Kiel who chaired the investigation.

The state government of Schleswig-Holstein in 1992 asked the commission to investigate the cause of an unusual cluster of leukaemia cases in the vicinity of the Krümmel nuclear power plant near Hamburg. Between 1989 and 1991, six cases of childhood leukaemia in the area put incidence about ten times higher than the German average. Today, the number of new cancer cases has dropped, but is still above average.

In 1996, a report from the Öko Institute — an independent environmental research institute critical of nuclear energy — ruled out a link to a reactor operated by the nearby GKSS research centre (see Nature 384, 398; 199610.1038/384398a0). Now the members of the Wassermann commission who resigned have added that the cluster cannot be blamed on the nuclear power plant either.

Wassermann claims to have found traces of radioactive products, including americium and plutonium isotopes, in soil near the GKSS centre. He says that the traces don't come from either Chernobyl fallout or from atomic bomb tests. Instead he suspects that the GKSS carried out “secret nuclear experiments” in the 1980s; a fire may then have released nuclear contamination that caused the cancer cluster, he says. An old aerial photo of the area shows a building that Wassermann takes to be a secret lab.

Hans-Friedrich Christiansen, a spokesman for the GKSS, denies that any kind of secret or unauthorized experiments have ever been carried out at the centre, and says that there has never been a large fire. The building in the photo could have been a bunker from the Second World War, he adds.

Erich Wichmann, an epidemiologist at the National Research Center for Environment and Health in Neuherberg, and a member of Wassermann's commission who did not resign, says that Wassermann's conclusions are too speculative. Moreover, he says, independent labs have since failed to find unusual radioactive substances in the area.

A government spokesman says that Schleswig-Holstein has spent €4.5 million (US$5.8 million) in 12 years to find the cause of the leukaemia cluster. The Wassermann commission was set to be wound up next February.