Washington ? The Senate gave final approval Wednesday to a $401.3 billion defense bill that gives the Pentagon greater control over its civilian work force and eases environmental restrictions on the military.

The bill authorizing 2004 defense programs now goes to President Bush for his signature.

Democrats joined Republicans in the 95-3 vote, despite their objections to the broader Pentagon authority. They stressed the measure would provide new benefits to both active duty soldiers and veterans.

But the bill was opposed by Sen. Robert Byrd, D-W.Va., who said it “transfers vast, unchecked powers to the Defense Department while avoiding any break with the business-as-usual approach to increasing defense spending.”

The bill is $1.5 billion more than the amount request by Bush and about 2.2 percent more than Congress approved last year. It was approved by the House on Friday in a 362-40 vote.

It raises salaries for soldiers by an average of 4.15 percent and extends increases in combat and family separation pay.

It would also partially reverse a policy set in the 1890s of reducing disabled veterans’ retirement benefits by $1 for every dollar received in disability pay. The change would be phased in over 10 years and mainly help the more seriously disabled — about a quarter-million veterans. It will cost $22 billion.

The Pentagon will have greater flexibility in hiring, firing and promoting civilian employees. It says current rules force it to use military personnel for jobs better suited for civilians. Democrats and unions say the bill hurts workers by weakening job protections, overtime rules and other rights.

The bill also lifts a decade-old ban on research into low-yield nuclear weapons and authorizes $15 million for continued research into the Robust Nuclear Earth Penetrator, capable of destroying deep underground bunkers.

The military construction bill is $1.4 billion below last year’s level, but $200 million over Bush’s request. Lawmakers added more than 100 projects for military facilities in their home districts that Bush had not requested.