The Obama administration's call for tighter federal oversight of oil and gas pipelines in the wake of a deadly California gas explosion is raising alarms about the safety of the nation's aging infrastructure.

But Congress is unlikely to act this year with midterm elections looming. And tough new laws could take years if some lawmakers have their way.

The Obama administration is asking Congress to increase from $1 million to $2.5 million the maximum fine for the most serious violations involving deaths, injuries or major environmental harm related to oil and gas pipelines.

The plan also would pay over the next four years for an additional 40 inspectors and safety regulators at the U.S. Pipeline and Hazardous Material Safety Administration, which is directly responsible for inspecting interstate pipelines and has only 100 inspectors to do it. Oversight of intrastate lines is left to local regulators, who have in most cases left the inspections to utilities.

Pipeline safety advocates welcomed the Obama plan, but said it fell far short of addressing the problems facing the nation's millions of miles of pipeline.

"It didn't go anywhere where we wanted it to go," said Carl Weimer, executive director of the Pipeline Safety Trust, a Bellingham, Wash., advocacy group.

"It's low-hanging fruit," Weimer told FoxNews.com, adding he doesn't think the energy industry will oppose the plan. "If you increase mileage that needs to be inspected, then you'll be in fight" with the energy industry, he said.

The White House proposal follows several accidents, including an oil spill from a pipeline owned by a Canadian company near Marshall, Mich., that sent an estimated 820,000 to 1 million gallons spewing into the Kalamazoo River in late July. Another spill from a pipeline by the same company, Enbridge Inc., was reported within the last week in suburban Chicago.

But the massive fire in San Bruno, Calif., a suburb of San Francisco, has captured the most attention. Federal investigators said they were examining whether Pacific Gas & Electric workers followed proper emergency procedures after a gas transmission line exploded into an inferno that killed at least four people and destroyed nearly 40 homes.

Congress is expected to recess for midterm elections within the next three weeks, making it unlikely a bill could be enacted within the next two months. Rep. James Oberstar, D-Minn., chairman of the House Transportation and Infrastructure Committee, said he wants the proposal at least approved by the pipeline subcommittee by then.

"I do think there is urgency," Oberstar said.

Some earlier proposals to improve pipeline safety have languished on Capitol Hill over concerns by energy companies.

Weimer said Capitol Hill aides told him they wanted a stronger proposal and that they'd "rather do it well than fast."

Pipeline safety experts characterized the administration's proposal as a step in the right direction -- but maybe not enough.

"It's good to give them an extra club if they use it," said pipeline engineer Richard Kuprewicz, whose company, Accufacts Inc., offers pipeline safety consultations to communities.

"They may issue a half-million dollar fine, but there's an appeal process and in the end it can be a real small number," he said.

In the meantime, the head of the National Transportation Safety Board said PHMSA is too accepting of assurances from industry that its equipment and practices are safe.

Deborah Hersman's comments echoed what safety advocates have long called for -- a pipeline agency that needs to be less cozy with industry and staffed with more inspectors to enforce stricter regulations.

Hersman said the NTSB, which is investigating the California blast and two other pipeline accidents, is concerned that PHMSA relies too heavily on documents submitted by the companies it regulates, rather than its own on site verification of practices and procedures.

"We want PHMSA to be on the ground doing the inspections," Hersman said. "We think it's PHMSA's responsibility to trust but verify."

PHMSA employees told lawmakers last year that during the Bush administration the agency was effectively run by a handful of lobbyists.

The Associated Press contributed to this report.