Congressional staff investigating the widening General Motors ignition switch recall of 2.2 million vehicles said Sunday there are indications GM approved the design of the switches in 2002 even though the company knew they did not meet specifications. Executives with Delphi, the Troy, Mich.-based supplier of the part, told investigators that GM accepted the switches now under recall despite knowing they did not meet the company's specifications. That disclosure, along with others in a memo to committee members Sunday, raises more troubling questions about why GM and federal regulators didn't act sooner to address a long-standing problem. The defective ignition switches have been linked to 13 deaths and 31 crashes. Several families of people who died in crashes are considering lawsuits and at least one class action regarding the vehicles has been filed as well. Sunday's memo from investigators for the House Energy and Commerce Committee comes as GM CEO Mary Barra is to testify before the Oversight and Investigations Subcommittee at a hearing Tuesday on Capitol Hill. GM is recalling Chevrolet Cobalts and HHRs, Saturn Ions and Skys and Pontiac G5s and Solstices to replace switches that can be inadvertently jostled out of position, potentially causing air bags not to deploy in the event of a crash. But the recall was ordered more than a decade after the first indications of switch problems. As early as 2001, during pre-production of the Ion, GM knew there were issues with the ignition switches, according to the company's time line of events leading to the recall. STORY: GM CEO should learn from past Hill debacles STORY: GM recalls new pickups, SUVs Greg Martin, a spokesman for GM, said the company is cooperating fully with congressional investigators to ensure they have a "full understanding" of GM's decisions. He did not directly address the claim that GM may have known the switches didn't meet specifications, however. Delphi executives did not return calls and e-mails for comment. As part of the investigation, committee staff collected 235,000 pages of documents from GM and its regulators at the National Highway Traffic Safety Administration (NHTSA). Investigators held closed-door briefings with officials from GM, NHTSA and GM's suppliers, Delphi and Continental, which produced the sensing module triggering air bag deployment. U.S. Rep. Tim Murphy, R-Pa., who chairs the Oversight and Investigations Subcommittee said the information collected through documents and briefings "paint an unsettling picture." NHTSA is under fire for not moving more quickly to force a recall. Federal regulators had received hundreds of complaints of cars stalling over the years and, as early as 2005, ordered an investigation into a crash where a 16-year-old girl died in a Cobalt, and the air bags did not deploy. According to e-mails, in September 2007, a top official in NHTSA's Office of Defects Investigation proposed a deeper look into "frontal air bag non-deployment in the 2003-2006 Chevrolet Cobalt/Saturn Ion," saying there was "a pattern of reported non-deployments," Sunday's memo said. GM, however, said it did not see a pattern and officials at the Office of Defects Investigation determined later that year that there was no discernible trend to the incidents and decided against a more formal investigation. Both Barra and David Friedman, NHTSA's acting administrator, will be questioned this week about the recall and why it took so long. Subcommittee members — including full committee Chairman Fred Upton, R-Mich., want to know whether GM's internal procedures are robust enough to catch defects and why the company would have approved switches that did not meet its own specifications. "Lives are at stake, and we will follow the facts where they take us as we work to pinpoint where the system failed," said Upton, who sponsored legislation in 2000 intended to ensure federal regulators had the data needed to detect safety issues earlier. "We now know the problems persisted over a decade, the red flags were many, and yet those responsible failed to connect the dots." Much of the 12-page memo put out by the committee staff Sunday reiterated information already made public but the 235,000 pages of documents — as well as briefings — did contain some new developments. Executives from Delphi told committee staff in a briefing that GM signed off on what's known as a Production Part Approval Process, or PPAP, document in February 2002 for the switch "even though sample testing of the ignition switch was below the original specifications set by GM." STORY: GM recall tests CEO Barra's top executives STORY: GM missed 'red flags' on deadly ignition switches It was not immediately known why Delphi would have provided a part that did not meet specifications, why GM would have accepted it or whether it was considered a potential problem at the time. Committee members are expected to pursue answers from GM as to why it would have accepted the part — especially since Cobalt engineers, in court depositions made public since the recall, have said themselves vehicles shouldn't have been sold if parts didn't meet specifications. Delphi executives also told committee staff that it was GM which finally requested a change to the part in 2006, which largely addressed the problem in some 2007 model year vehicles and those thereafter. However, because some of the original switches were sold as after-market parts, GM can't be sure how many of those may have eventually ended up in other model year cars — leading to last week's expansion of the recall. Even that decision to fix the part, however, appeared to run into difficulty, according to congressional investigators. Records indicated that in 2005 — after GM opened an internal probe into issues reported with the switches — the company considered addressing the problem with a design change. But a GM engineer said it would be "close to impossible to modify the present ignition switch." Even so, GM personnel signed off on a change largely addressing the problem just the following year. It wasn't until 2013 when internal investigators at GM even figured out that the part had been ordered changed by at least one of its own engineers. Delphi executives told the committee that although that 2006 change led to "a significant increase in ... performance" it was still below GM's original specifications. There also were indications that NHTSA considered a defect investigation in 2010 but again decided not to pursue it. Tuesday's House hearing, which is set for 2 p.m. EDT, is just part of what is likely to be a long week for GM and federal regulators. A Senate subcommittee will hold a hearing on the recall Wednesday and NHTSA is expected to receive answers to 107 questions it put to GM about the timing of the recall Thursday. GM, however, could still have protection on any claims against it for crashes involving the vehicles prior to July 2009. As part of its bankruptcy reorganization, product claims were separated from the new company's liabilities. Lawyers, however, could try to get that shield removed if it can be shown that GM executives knowingly misled the bankruptcy court about the threat posed by the switches. The U.S. Department of Justice is also said to be investigating GM's handling of the recall.