The U.S. Government Accountability Office is expected to issue the report on Wednesday.
It comes a month after a 20-inch line owned by NiSource subsidiary Columbia Gas Transmission ruptured in West Virginia , triggering a massive fire. The Dec. 11 inferno destroyed four homes, damaged several others and charred a section of Interstate 77.
No one was seriously injured.
U.S. Sen. Jay Rockefeller has scheduled a hearing of the Senate Commerce Committee that he chairs to look into pipeline safety. The field hearing will be held Jan. 28.