BONN, Germany -- As Germany belatedly moves to lend military assistance to the U.S.-backed front against Iraq, evidence is mounting here of vast West German involvement in building up Iraq's chemical, biological and nuclear weapons systems, with exports continuing even after the Iraqi invasion of Kuwait Aug. 2.
A confidential briefing to the West German Bundestag's Economic Committee by Economics Minister Helmut Haussmann in late August portrayed West German involvement in major areas of Iraqi weapons development. A source on the committee said the level of cooperation was "worse than we expected."
And a report released last week by the Simon Wiesenthal Center in Los Angeles found that of 207 companies that cooperated with Iraq in building up its chemical, biological and nuclear weapons programs, 86 were German.
"The question is, if the Germans hadn't been there, where would the Iraqis be?" asked one Western diplomat. "I don't think they'd be very far, because the Germans provided the high technology."
Mr. Haussmann's briefing, taken with the Wiesenthal Center's report, suggests deep German involvement in six major areas of Iraqi weapons production:
* To advance Iraq's nuclear capability, three German companies supplied Iraq with critical parts to build gas centrifuges for the cheap production of enriched uranium. The technology was held only by the Dutch and the Germans.
The advantages of the gas centrifuges, each of which spins out only a minuscule amount of enriched uranium, lie in their low cost and relatively low profile. "You don't have to spend $30 billion building a nuclear processing plant like in the United States," a Western diplomat said. In addition, parts for the gas centrifuges can be bought from a number of suppliers, making their final use less evident to outside monitors.
* At least four companies were instrumental in building Iraq's chemical weapons complexes, which already have produced mustard gas (the blistering agent used on Kurdish civilians in July 1988 and against Iran), cyanide, sarin, tabun and prussic acid (which eats away at gas masks). The most important of these complexes is near the holy city of Samarra, north of Baghdad.
* One principal contractor and at least seven smaller firms helped build the Saad-16 facility in Mosul, a vast center for the research and development of nuclear and chemical weapons and delivery systems.
* Five companies were involved in upgrading Iraq's Soviet-made Scud-B missiles, modernizing them to deliver chemical weapons with increased range and accuracy.
The Wiesenthal Center report concludes that "while there is no firm evidence that Iraq has managed to develop chemical warheads for its medium-range ballistic missiles, there can be no doubt that this is one of Iraq's top priorities."
* Six companies were involved in supplying components for Iraq's 495-foot supercannon, which it has not succeeded in completing.
* One company was chiefly responsible for building the Taji complex, which produces artillery and other weapons.
"Iraq . . . is self-sufficient in the production of ammunition for its tanks and artillery. There is also a capacity for producing ballistic missiles and artillery rockets," an August 1990 report by the Stockholm International Peace Research Institute concluded.
In addition, West German companies have supplied Iraq with small amounts of the mycotoxins TH-2 and T-2, which are used in developing the agents of biological warfare, according to the Wiesenthal report.
The technology of a German company that produced fuel-air explosivebombs under contract with Egypt until 1988 also is reported to have found its way to Iraq. The small bombs are easy to produce and are said to be as destructive as a small atomic bomb.
Last Tuesday, German prosecutors announced they had arrested seven people Aug. 17 on suspicion of supplying Iraq the technology to make chemical and other weapons. Among those arrested were Peter Leifer, a managing director of Water Engineering Trading GmbH of Hamburg, and Ewald Langer, an TC engineer with the Pilot Plant GmbH of Dreieich, Germany.
The two companies had been named as major offenders in the supply of chemical weapons to Iraq as early as November 1987, when Bonn began its investigation with a search of 29 companies and private businessmen.
But sources said the investigations had been hampered by conflicting messages from government circles over whether the trade with Iraq should be stopped.
"When you sold anything, even a pesticide plant, to the Iraqis, it was held in a positive sense here, and it was allowed to get way out of hand," said a diplomat.
There was also an overriding belief in business circles that if West German companies did not provide the technology or parts, French or British firms would.
And until the Iran-Iraq war ended in 1988, many Western governments saw the regime of Iraqi President Saddam Hussein as a kind of shield against the advance of Iran's Moslem fundamentalism.