Michael Millikin, general counsel of General Motors Co., best wear some asbestos pants Thursday when a U.S. Senate panel probes why his legal department failed to report a pattern of problems with an ignition switch that cost at least 13 people their lives.

Millikin takes the hot seat as the chairwoman of the hearings said she intends to focus questioning on GM’s legal department. His testimony also comes a day after The New York Times reported that newly released documents raise questions whether GM concealed facts about the ignition defect in its responses to safety regulators on fatal crashes.