General Motors decided not to go through with a proposed ignition-switch fix in the Chevrolet Cobalt nearly a decade ago due to costs, a House subcommittee found during the investigation into defects in around 2.6 million vehicles.

Both GM and the National Highway Traffic Safety Administration bypassed opportunities to fix the issue that has since been related to 13 deaths, Bloomberg Businessweek reported.

Documents from GM and the federal agency have unearthed "unsettling" information, said Republican Representative Tim Murphy, as reported by Reuters. A solution for the vehicle's ignition switch failure was canceled in 2005 by the automaker, while the NHTSA chose not to open a formal investigation into the defect in 2007.

At the time, federal officials opted out of the probe despite evidence that included four fatal crashes, 29 complaints and 14 other reports showing the defect stopped air bags from deploying properly, revealed a memo from a House subcommittee on Sunday, The New York Times reported.

The NHTSA failed to respond again in 2010, when the agency received more reports of disabled air bags.

The same memo showed that GM let a faulty ignition switch design go into production in 2002 in spite of warnings from the part supplier, Delphi, which told GM the switch fell short of specifications, according to the Times.

As part of the investigation, a House subcommittee has brought together some 200,000 pages of documents from GM as well as 6,000 pages from the NHTSA and will hold a hearing on Tuesday. The carmaker's recently appointed CEO, Mary Barra, is slated to testify along with David Friedman, acting administrator of the NHTSA.

Under Barra's direction and in the wake of the massive recall, GM seems to have grown unusually cautious, The Washington Post reported.

The carmaker recalled more than 1.5 million vehicles earlier this month to inspect brakes, air-bag wiring and other components. Additionally, 662,000 more vehicles were recalled this weekend for potential problems.

"For the first few days, it was the classic old-style GM: Say as little as possible and, above all, keep the chief exec as far away from it as you can. Then suddenly, overnight, everything changed," said Marina Whitman, a professor at the University of Michigan and a former economist at GM.

"It's pretty clear that Mary Barra had taken charge and said, 'This is not me.' "

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