Some of the nation’s most prominent plaintiffs firms, many of them veterans of litigation against Toyota Motor Corp. and with ignition-defect lawsuits pending against General Motors Co., have a fresh target: Air bag manufacturer Takata Corp.

Takata has come under scrutiny from federal regulators and Congress over a defect that could cause its air bags to explode, pelting drivers with metal shrapnel. About 7.8 million U.S. cars and trucks made by 10 auto companies have been recalled.