CHICAGO, July 10 (Xinhua) -- Human error caused a natural gas pipeline explosion in U.S. Illinois state last year, which left two people dead, two others injured, an official investigation has concluded.
Federal investigators said that "third-party damage," in other words, human error, was the reason for the accident, local media reported on Tuesday.
On December 5, two farmers, with the help of two other workers, were installing drainage tile on land they had leased for years in Nachusa, some 150 kilometers west of Chicago, when the tiling plow ruptured a high-pressure natural gas pipeline.
The father and son farmers died in the blast and two workers survived with injuries.
Federal investigators found that the farmers failed to report their digging work in advance, as required by law, to relevant authorities, who could have informed them of the potential danger about the underground gas pipeline.
"It is possible that this incident might have been prevented if such a notice was provided," said the investigation report.
Beside the casualties, the report put the damage at 888,700 U.S. dollars.
