As lawmakers press General Motors and regulators over their decade-long failure to correct a defective ignition switch, a new review of federal crash data shows that 303 people died after the air bags failed to deploy on two of the models that were recalled last month.

The review of the air bag failures from 2003 to 2012, by the Friedman Research Corporation, adds to the mounting reports of problems that went unheeded before General Motors announced last month that it was recalling more than 1.6 million cars worldwide because of the defective switch. G.M. has linked 12 deaths to the faulty switch in the two models analyzed, the 2005-7 Chevrolet Cobalts and 2003-7 Saturn Ions, as well as four other models.

The review by Friedman Research, a company that analyzes vehicle safety data, looked at cases in which the air bags failed to deploy, but it did not try to evaluate what caused the crashes.

The Center for Auto Safety, a private watchdog group in Washington, commissioned the study, and, in a letter to the National Highway Traffic Safety Administration, criticized the agency for not detecting the air bag failures, as well as the defective ignition switch.