General Motors Co. changed the design of ignition switches in certain midsize cars in 2003 and 2004 after discovering that the force of a swinging, heavy key chain could turn the vehicles off, but company officials didn't treat the problem as a safety issue and order a recall of the vehicles until June 2014, according to a document filed with federal regulators on Friday, reported The Wall Street Journal.

The document provides more details on GM's June 30 recall of 7.6 million midsize cars. Among the recalled cars are 2000 to 2005-model Chevrolet Impalas. GM says it knows of two accidents, involving three fatalities, in which air bags in a 2003 and a 2004 Impala failed to deploy. It is not known whether the ignition switches in those cars had slipped out of the run position, GM spokesman Alan Adler said Friday.

While GM changed the ignition switch designs of other midsize cars made in that period to make it harder for keys to rotate out of the run position, Mr. Adler said the ignition switch of 2000-2005 Impalas wasn't changed in that way.

GM's chronology of the events leading to the June 30 recall also highlights the difference in the way the company is responding now to potential safety defects compared to a decade ago.

In 2003, the GM document states, company officials learned of a customer complaint that a Pontiac Grand Am would shut off intermittently. A GM brand quality manager visited the dealership, and asked the car's owner to demonstrate the problem. The customer had a key ring "containing approximately 50 keys and a set of brass knuckles," the document states. When the car drove over a speed bump at 30 to 35 miles an hour, it shut down, the chronology states.

On May 22, 2003, GM issued a voice mail to dealers warning them to pay attention to the mass attached to key rings. On July 24, 2003, GM ordered a change in the design of the ignition switches used in Chevrolet Malibus, Pontiac Grand Ams and Oldsmobile Aleros. The change increased the force required to rotate the keys, and a new part number was issued.

In March 2004, a separate order was made to change the "detent plungers" in the ignition switches installed on Pontiac Grand Prix midsize cars, the chronology states. In this case, GM didn't change the part number, the chronology states.

More than a decade later, on May 22, 2014, an official of the National Highway Traffic Safety Administration questioned GM officials about a 2003 service bulletin issued for the Malibu, Grand Am and Alero.

Since the disclosure of the delay in recalling the Cobalt and other small cars, GM has been fined $35 million by NHTSA and is under investigation by federal prosecutors, two congressional committees and other federal and state regulators.