The Senate agreed Wednesday to let the government regulate security for now at chemical manufacturing plants, a first step in improving protection against potential terrorist attacks.

The limited authority for the Homeland Security Department was approved as the Senate debated the agency's proposed $32.7 billion spending bill for the budget year that begins Oct. 1.

In an election year when homeland security looms as a prominent issue, the Senate also agreed to bolster U.S. borders against illegal immigrants and reduce airport delays by lifting a ban on hiring more than 45,000 security screeners. But Republican lawmakers blocked Democrats' proposals to increase spending for rail security programs and big-city counterterror grants.

Experts believe the chemical industry is a top target of terrorist organizations. Congress for years has considered -- though never approved -- ways to regulate the chemical industry akin to other potentially vulnerable targets like nuclear power facilities and commercial airports. Both the House and Senate are considering legislation to make this authority permanent, though Senate aides said approval may not come until next year.

"The potential devastation demands that we take steps now to secure these chemical facilities," said Sen. Robert Byrd, D-W.Va. "There's been enough talk. It's time to act."

The Senate proposal would give the department the power to regulate the industry as it sees fit for now.

Earlier this year, Homeland Security Secretary Michael Chertoff called for regulatory power that largely would let the industry decide on protections and leave inspections to private auditors. Critics said the proposal was a toothless fix.

Currently, chemical companies voluntarily secure their facilities.

The Senate also approved several programs to boost border security, including $50 million for more police and equipment for border communities, and to step up surveillance on the Canadian border to counter heavy attention on stopping illegal immigration at the Mexican border.

"The northern border has a high risk of terrorists coming across it," said Sen. Judd Gregg, R-N.H. "Therefore we cannot ignore that border."

In another high-profile debate, senators agreed this week to scrap the Federal Emergency Management Agency and rebuild it in an attempt to avoid future disaster response failures like those highlighted in Hurricane Katrina's aftermath.

The new agency, which would remain part of Homeland Security, would combine emergency preparedness and response missions and could report directly to the president during catastrophes. Its blueprint was the result of a seven-month investigation led by Sens. Susan Collins, R-Maine and Joseph Lieberman, D-Conn., who beat back an attempt to pull FEMA out of Homeland Security that was offered by Sen. Hillary Rodham Clinton, D-N.Y.

Senators hope to wrap up the mammoth spending bill at the end of the week; the House last month approved its own $32 billion version.