General Motors may be in hot water over a 2.6-million vehicle recall that has been related to 13 deaths, but the National Highway Traffic Safety Administration is in the spotlight as well for reportedly ignoring the issue for nearly a decade.

The agency has defended its efforts but acknowledged that changes should be made to the limited budget for defect investigations, The Detroit News reported.

In a U.S. Senate hearing on Wednesday, Acting NHTSA Administrator David Friedman said the agency's defect investigations unit comprises just 51 people and uses a mere $10.1 million of the NHTSA's $800 million budget. The amount of money used to examine auto defects has remained flat for around 10 years.

"Do you believe that $10 million is adequate to spend in this country for defects investigation for the entire automobile industry?" asked Sen. Claire McCaskill, D-Mo., chairwoman of the Subcommittee on Consumer Protection, as quoted by The Detroit News. "We need to have the resources and the expertise at NHTSA to find these defects."

GM is being investigated by the Justice Department; CEO Mary Barra has also stated that the company is doing an internal investigation to see why the problem was overlooked for so long.

A separate probe will be launched into the NHTSA to investigate why the agency didn't look into the ignition switch problem related to the GM recall, said Transportation Department Inspector General Calvin Scovell III.

The investigation will "determine what NHTSA knew of this safety defect, when it knew it and what actions NHTSA took to address it," said Scovell, as quoted by The Detroit News.

In 2007, an NHTSA investigator requested a formal investigation of Chevrolet Cobalt vehicles after reports of four fatal crashes, but the probe was canceled by his superiors.

The recalled vehicles can have ignition switch problems that cause the car to turn off while still moving and stop the airbags from deploying properly. While the ignition switches are apparently sensitive to heavy key chains and bumps, many are wondering why the air bags are affected.

GM officials have said the shifting ignition keys can cut off the power to the air bags, but Friedman said Wednesday that the issue could also be found in the algorithm written by the automaker, The Detroit News reported.

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