Speaking at a hearing of the Truth and Reconciliation Commission, Daan Goosen described a search for an unnamed European scientist alleged to know about a bacteria that would only harm blacks.
The information came from the military attache at the South African Embassy in London in 1983 or 1984, Goosen said.
Goosen said his research into scientific literature and journals led him to believe it could be a feasible project, but he backed out of a planned trip to London to find the scientist because he feared it could be a trap.
Goosen said he had conducted the research on orders from Dr. Wouter Basson, an army physician who set up a sophisticated network of front companies to research biological and chemical weapons. Goosen headed a covert military research laboratory under Basson's control.
"A thing like this can be used to maintain peace," Goosen said. "Peace means being the strongest power."
He admitted that hindsight showed his work was not ethical. But he said the prospect of keeping order amid an increasingly resistant black population during apartheid's most turbulent time gave impetus to Basson's work.
"I was not thinking rationally at the time. Today I know I was wrong. You can't do that to people, it is just not justifiable," Goosen said.
Since Monday, the panel that is investigating apartheid-era crimes has also been hearing scientists describe working in a poison factory that put deadly substances into drinks and cigarettes that were passed onto apartheid hit squads.
The scientists said that government agents considered poisoning Nelson Mandela and failed in an attempt to poison anti-apartheid cleric Frank Chikane, now a top adviser to Deputy President Thabo Mbeki.
Police forensic scientist Lothar Neethling testified Thursday that Basson researched using drugs confiscated by police as a method of riot control.
Neethling said he supplied Basson with up to 200,000 tablets of the depressant mandrax, 5,000 tablets of LSD and 250 kilograms of marijuana plants. The research aimed to turn the drugs into gas and put them inside grenades. It failed to produce a viable product, Neethling said.
The Truth Commission was set up by Mandela in 1995, a year after South Africa's first all-race elections swept the African National Congress into power and ended apartheid.
On Wednesday, the ANC compared the former apartheid government with Adolf Hitler's Third Reich, which used scientists to devise ways of exterminating millions of Jews, Gypsies and others.
Written by Paul Harris