(CFP)

The mystery surrounding the controversial joint China-U.S. test of genetically-modified (GM) rice on school children in central China's Hunan Province unraveled as a researcher who conducted the test and two officials who had approved it were recently removed from their posts.

A joint statement released on December 6 by the trio's employers said that they had been disciplined for "violating relevant government regulations, scientific ethics and academic integrity."

The Chinese Center for Disease Control and Prevention (CDC) and the Hunan Provincial CDC demoted Yin Shi'an and Hu Yuming, respectively, and the Zhejiang Academy of Medical Sciences all but fired Wang Yin.

All three are co-authors of a paper published online in early August and in the American Journal of Clinical Nutrition in September, claiming that "beta carotene in 'golden rice' is as good as beta carotene in oil at providing vitamin A to children."

In late August, Greenpeace disclosed that the paper is based on findings from a test in which researchers fed the genetically engineered rice to 25 children aged 6 to 8 in Hunan.

The Ministry of Health later ordered the Chinese CDC to investigate whether children in Hunan were used as test subjects.

The investigation revealed that the test was conducted in 2008 on 80 students in Hengnan County, with 25 of them each being fed 60 grams of "golden rice" on June 2, 2008. Children, parents and school officials were not informed that the rice was genetically modified during or before the experiment.

The three Chinese institutions apologized in a joint statement.

Controversial research

"Golden rice" was invented in the 1990s through genetic engineering by Ingo Potrykus at the Swiss Federal Institute of Technology and Peter Beyer of the University of Freiburg in Germany.

The rice was developed to combat vitamin A deficiency. The World Health Organization estimated that each year up to 50,000 children go blind from vitamin A deficiency, half of whom dying within a year of losing their sight.

"Golden rice" has been shrouded in controversy since it was made public in the prestigious Science magazine in 2000. That year, Time magazine put the rice on its cover, hailed it as the "Grain of Hope" and declared, "This rice could save 1 million kids a year." Opponents questioned the potential health hazards of GM food.

In December 2002, the U.S. National Institute of Health (NIH) approved research aimed at finding out how efficiently beta carotene in "golden rice" can be converted to vitamin A once it's ingested. The project's leader is Tang Guangwen, a Chinese-born American scholar at Boston-based Tufts University.

The project lasted for several years. When its findings were published in August, Greenpeace questioned the ethics of testing GM rice on Chinese children in Hunan.

Greenpeace's exposure stirred up a media frenzy, raising concerns over the safety of GM food and sparking outrage over Chinese children being used as guinea pigs for the U.S.-sponsored research project.

Under public scrutiny, the three Chinese co-authors denied their involvement in the project. Wang told People's Daily that she was unaware of the paper. Yin said that researchers only gave the schoolchildren spinach and capsules, and he was not aware of the "golden rice" part of the project. However, Yin's account of the event was inconsistent with those of Tang. In September, the Chinese CDC had Yin suspended.