The Senate, acting against a backdrop of threatened chemical and biological attacks on U.S. troops in the Persian Gulf, gave final approval yesterday to legislation aimed at assuring compensation for Vietnam War veterans who were exposed to Agent Orange.

The legislation, stalled for years in a dispute over the health effects of the herbicide, was approved 99 to 0 by the Senate and sent to President Bush, who has indicated he will sign it. It had been approved unanimously by the House on Tuesday.

"It is ironic that as we are finally dealing with this issue there are men and women facing the threat of chemical and biological warfare in the Persian Gulf," said Sen. Thomas A. Daschle (D-S.D.), a Vietnam veteran and chief sponsor of the Senate bill.

"Veterans of the Vietnam War have waited over 20 years for a meaningful response to the complex issues surrounding their hidden wounds," Daschle added. "I can only hope that if veterans of the war with Iraq suffer their own hidden wounds, they will not have to endure that same fate."

Daschle and others said they believe Iraq's threat to use chemical and biological weapons against allied troops was a factor in breaking the deadlock that killed the bill, along with other veterans legislation, in the waning days of last year's session of Congress.

The bill codifies -- and thus makes permanent -- a directive by Veterans Affairs Secretary Edward J. Derwinski that extends disability benefits to Vietnam veterans suffering from two forms of cancer, non-Hodgkin's lymphoma and soft-tissue sarcoma, on the presumption that the diseases were caused by Agent Orange. It also provides coverage for those suffering from chloracne, a severe form of acne, that became apparent within one year after service in Vietnam; the current limit is three months.

The bill goes beyond Derwinski's directive in giving the National Academy of Sciences the key role in deciding whether other diseases resulted from exposure to Agent Orange and other herbicides used to clear jungles during the Vietnam war. The academy would review scientific evidence and report to the VA secretary, who would then decide which diseases qualify for compensation.

The bill also extends veterans' eligibility for free medical care for Agent Orange disability through December 1993. Current statutory requirements for care expired at the end of last year.

In yesterday's roll call, the only senator not voting was Alan Cranston (D-Calif.), chairman of the Veterans Affairs Committee and a key backer of the legislation, who is undergoing treatment for prostate cancer in California.

The House also passed, 399 to 0, legislation to provide special pay increases to retain and recruit physicians and dentists for the Veterans Administration, which has experienced a shortage of health care workers.

In addition, the Senate Armed Services Committee approved five measures to benefit military personnel, including ones that would raise combat pay from $110 to $150 a month retroactive to Aug. 1, 1990 and double the maximum life insurance benefit from $50,000 to $100,000 for active duty personnel and for veterans. The Senate is expected to consider the legislation next month.