Lawyers representing U.S. supermarket chain Wal-Mart have fired back at comedian Tracy Morgan's personal injury lawsuit, insisting they have it on good authority the funnyman was not wearing a seatbelt when the car he was a passenger in collided with a truck earlier this year (14).

The former 30 Rock star was seriously injured in the resulting six-car accident in New Jersey and required hospital treatment and extensive recovery. His mentor James 'Jimmy MACk' MCNair lost his life in the crash.

Morgan has since filed suit against Wal-Mart executives, suggesting the company's driver Kevin Roper wasn't monitored for fatigue after driving hundreds of miles from his home in Jonesboro, Georgia before starting work for Wal-Mart on the day of the fatal accident, and that, therefore, the company was negligent.

But now Wal-Mart lawyers are hitting back, claiming that the comic's injuries and those of the others involved in the crash were caused, in whole or in part, "by plaintiffs' failure to properly wear an appropriate available seatbelt restraint device".

The supermarket chain's response to Morgan's suit reads: "By failing to exercise ordinary care in making use of available seatbelts, upon information and belief, plaintiffs acted unreasonably and in disregard of plaintiffs' own best interests."