The suit, filed in a Brooklyn federal court in New York, seeks class action status on behalf of some 100,000 veterans suffering from illnesses including memory loss, deterioration of the central nervous system and chronic fatigue.
The case seeks unspecified damages and a court order forcing the defendants to pay for medical monitoring of the veterans and their children.
Among accusations in the suit is a charge that the defendants violated international laws barring the use of chemical weapons.
The plaintiffs say that they were exposed to sarin nerve gas, mustard gas and other chemical agents manufactured and obtained by Saddam Hussein's government.
They said they were exposed to the chemicals when United States and allied forces blew up hundreds of Iraqi ammunition dumps.
During the war US and allied forces are known to have used depleted uranium weapons against Iraqi targets.
This radioactive material causes severe illnesses similar to those cited by the plaintiffs.
The Defendants include 11 companies that supplied chemicals and equipment to Iraq and 33 banks that helped finance the transactions. Most of the defendants are based overseas but do business in New York.
Some lawyers involved in the case had earlier filed a 1994 suit in Texas on behalf of Gulf War veterans injured by chemical agents.
Plaintiffs' lawyers said the Brooklyn case includes defendants whose identities were recently revealed in Iraqi disclosures made to United Nations weapons inspectors.