CHICAGO, Dec. 5 (Xinhua) -- A natural gas pipeline explosion in the central U.S. state of Illinois has killed two people and seriously injured two others, authorities said on Tuesday.
Farm workers were attempting to free a tractor stuck in a field in Lee Country, some 160 kilometers west of Chicago, when the underground pipeline exploded, said Lee County Sheriff John Simonton.
Two people were killed in the accident. One of the injured men is in critical but stable condition, while the other is in stable condition, said Simonton.
According to the energy company that owns the pipeline, the one that was struck is a 50-cm cross-country transmission pipe, which is usually buried 1.2 to 1.5 meters underground.
An investigation of the accident was underway.