Lawyers for the family of a limousine driver who died along with 19 others in an upstate New York accident and the owner of the vehicle are clashing over the cause of the deadliest U.S. transport accident in nearly a decade.

New York State police said the driver, 53-year-old Scott Lisinicchia, did not have the proper license to operate the 2001 Ford Excursion limousine that crashed in Schoharie, New York, on Saturday night and that the vehicle had failed inspection last month.

A lawyer for Prestige Limousine, which owned the vehicle, said the safety violations that led it to fail inspection last month were largely minor and did not cause the crash.