Unburned fuel from rockets launched at the Baikonur Cosmodrome in Kazakhstan is causing serious illnesses in children who live near the site, a leading science journal said on Wednesday.

Researchers from Vector, the State Research Centre of Virology and Biotechnology in Novosibirsk, showed in an unpublished study that children in areas of Siberia where the fuel is sprayed during take-off suffer serious health problems.

“The level of some diseases such as endocrine and blood disorders in polluted areas is more than twice the regional average, they say,” according to the journal Nature.

Baikonur, which is used by the Russian space agency, Rosaviakosmos, the European Space Agency (ESA) and NASA, is the launch pad for many missions to the International Space Station and a source of income for the Russian government.

An unnamed expert in the country’s space industry told the journal that profit from an individual commercial launch could be as much as $25 million.

Nature, a peer-review journal, said it published the report as a news story because it has important implications.

“The first detailed epidemiological study of people living under the flight path suggests that the rocket fuel is indeed causing health problems,” it said in an editorial.

Vector scientist Sergey Zykov estimates dozens of litres of unburned fuel from spent rocket stages containing toxic substances are sprayed over several kilometres during a launch.

“Most other major bases used by NASA and ESA, such as Cape Canaveral in Florida, send rockets out over the ocean,” the journal said.

When Nature approached Rosaviakosmos about the study, it rejected the findings. Other scientists who have raised the issue told the journal they had been arrested or harassed. Local environmental groups have also campaigned against the pollution.

“Despite using Baikonur for launches, neither NASA nor ESA accepts responsibility for the problems associated with the site,” the journal said.

NASA admitted it was aware of the pollution but said Rosaviakosmos has made “positive progress” in reducing the quantity of fuel released. ESA said it is not responsible for the rockets because it is only buying the service of the cosmodrome.

The Vector scientists discovered the increased rate of illness when they compared the health records of 1,000 children from the Altai Republic, a region in southern Siberia, in 1998-2000 with 330 records from an unpolluted region nearby.

“Grouping all cases of disease together, Zykov’s team concluded that children from the worst affected area were up to twice as likely to require medical attention during the three years studied and needed to be treated twice as long,” Nature added.